Patent Publication Number: US-2022226008-A1

Title: Clot retrieval system

Description:
BACKGROUND 
     Technical Field 
     The present invention relates to a deployable system for removing a blood clot or other object from a lumen of an animal. 
     Background of the Invention 
     Acute ischemic strokes develop when a blood clot (thrombus) blocks an artery supplying blood to the brain. Needless to say, when a blood clot creates such a blockage, time in removing the clot is critical. 
     The removal of intracranial obstructions is limited by several factors, such as the distance of the intracranial obstruction from the femoral access site, the tortuosity (twists and turns in the artery as it enters the base of the skull) of the cervical and proximal intracranial vasculature, the small size of the vessels and the extremely thin walls of intracranial vessels, which lack a significant muscular layer. These limitations require a device to be small and flexible enough to navigate through tortuous vessels within a guide catheter and microcatheter, expand after delivery at the site of occlusion and be retrievable into the microcatheter and yet be strong enough to dislodge strongly adherent thrombus from the vessel wall. In addition, the device should distally entrap or encase the thrombus to prevent embolization to other vessels and to completely remove the occlusion. The device should be retrievable without the need for proximal occlusion of the vessel, which carries risk of further ischemia and risk of vessel injury. The device should be simple to use and be capable of multi-use within the same patient treatment. The device should not be abrasive and should not have sharp corners exposed to the endothelial layer of the vessel wall. 
     Currently available intravascular thrombus and foreign body removal devices lack several of these features. Currently available devices include the MERCI™ RETRIEVER clot retriever device marketed by Concentric Medical, Inc. (Mountainview, Calif.), the PENUMBRA™ system marketed by Penumbra Inc. (Alameda, Calif.) to retrieve clots, and the newer stent retrieval devices TREVO™ (Stryker, Kalamazoo, Mich.) and SOLITAIRE™ (eV3 Endovascular Inc., Plymouth, Mass., which is a subsidiary of Covidien). All the devices are ineffectual at removing organized hard thrombus that embolize to the brain from the heart and from atherosclerotic proximal vessels. These “hard” thrombi constitute the majority of strokes which are refractory to medical treatment and are therefore referred for removal by mechanical means through an endovascular approach. The MERCI retrieval system is comprised of coiled spring-like metal and associated suture material. The method of use is deployment distal to the thrombus and by withdrawing the device through the thrombus, the thrombus becomes entangled in the coil and mesh and then is retrieved. The MERCI system requires occlusion of the proximal vessel with a balloon catheter and simultaneous aspiration of blood while the thrombus is being removed. Most of the time, the device fails to dislodge the thrombus from the wall of the vessel and often, even when successfully dislodging the thrombus, the thrombus embolizes into another or the same vessel due to the open ended nature of the device. 
     The next attempt at a thrombus removal system was the PENUMBRA. The PENUMBRA is a suction catheter with a separator that macerates the thrombus which is then removed by suction. The device is ineffective at removing hard, organized thrombus which has embolized from the heart, cholesterol plaque from proximal feeding arteries and other foreign bodies. 
     The SOLITAIRE and TREVO systems are self-expanding non-detachable stents. The devices are delivered across the thrombus which is then supposed to become entwined in the mesh of the stent and which is then removed in a manner similar to the MERCI system. Again, these devices are ineffectual at treating hard thrombus. In fact, the thrombus is often compressed against the vessel wall by the stent which temporarily opens the vessel by outwardly pressing the clot against the vessel wall. Upon retrieval of the devices, the clot remains or is broken up into several pieces which embolize to vessels further along the vessel. 
     Thus, there is a need for new, easy-to-use, easy-to-manufacture, safe surgical devices for removing obstructions, such as blood clots, from internal lumens of humans and other animals in a timely manner. 
     BRIEF SUMMARY 
     The present disclosure provides several systems for removing obstructions and other objects within a blood vessel or other lumen of an animal. The system may be deployed in the lumen from a distal end of a catheter and, in some embodiments, includes a pull wire having a proximal end and a distal end; a distal body attached to the pull wire, the distal body comprising an interior, an exterior, a proximal end, a distal end, a plurality of proximal memory metal strips located at the proximal end, a proximal hub located in the distal body interior, and a distal hub located distal relative to the proximal hub. The distal body has a relaxed state wherein the distal body has a first height and width and a collapsed state wherein the distal body has a second height and width, the second height less than said first height, the second width less than the first width. The system further includes a catheter having an interior, a proximal end leading to the interior and a distal end leading to the interior, the catheter comprised of a biocompatible material and configured to envelope the distal body when the distal body is in the collapsed state. Each of the proximal memory metal strips has a proximal end and a distal end and preferably, in the relaxed state, each of the proximal ends of the proximal memory metal strips is located proximal relative to the proximal hub. Preferably, in the relaxed state, the proximal ends of the proximal memory metal strips are configured to move towards each other and towards the pull wire when an operator moves the proximal hub distally and closer to the stationary distal hub (i.e., when the operator decreases the distance between the hubs). Preferably, in the relaxed state, the proximal ends of the proximal memory metal strips are configured to move away from each other and away from the pull wire by moving the proximal hub proximally away from the stationary distal hub (i.e., when the operator increases the distance between the hubs). 
     Optionally, the system further includes a plurality of memory metal connector strips, the plurality of memory metal connector strips each having a proximal end attached to a proximal memory metal strip and a distal end attached to the proximal hub. Optionally, the connector strips are integral with the proximal hub (i.e., optionally, the connector strips and the proximal hub are formed from the same piece of memory metal). Optionally, the proximal hub is a tube having an aperture and the pull wire passes through the aperture. Optionally, in the relaxed state, the proximal hub is slideable along the pull wire (i.e., at least a segment of the pull wire). Optionally, in the relaxed state, the proximal memory metal strips are distributed substantially evenly about a perimeter of the distal body. Optionally, the distal hub is a tube having an aperture. Optionally, the distal hub is attached to the pull wire such that the distal hub is not slideable along the pull wire. Optionally, the distal body further comprises a lead wire extending distally from the distal hub. Optionally, the distal body comprises a basket comprised of a plurality of memory metal strips distal relative to the proximal memory metal strips. Optionally, the distal hub, the proximal hub, and the distal basket are comprised of a nitinol having the same material composition. Optionally, the distal body further comprises an x-ray marker. Optionally, the proximal memory metal strips form a claw, the claw having a closeable proximal end formed by the proximal ends of the proximal memory metal strips. Optionally, between 2 and 4 proximal memory metal strips form the claw. Optionally, the distal body, in the relaxed state, has a tapered shape in which the distal body height and width decrease from the proximal end to the distal end. Optionally, the distal body, in the relaxed state, has a bullet shape. Optionally, the proximal hub and the distal hub are generally cylindrical in shape and each has an outer diameter and an inner diameter that forms the apertures of the proximal and distal hubs, the outer diameters of the proximal and distal hubs are substantially the same size, and the inner diameters of the proximal and distal hubs are substantially the same size. Optionally, the outer diameters of the proximal and distal hubs are from about 0.011 inches to about 0.054 inches, and the inner diameters of the proximal and distal hubs are from about 0.008 inches to about 0.051 inches. Optionally, the pull wire is generally cylindrical and the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Optionally, the proximal memory metal strips have a length of between about 10 and about 60 millimeters. Optionally, the first height and first width of the distal body are between about 2 millimeters (mm) and about 6 millimeters. Optionally, the proximal memory metal strips are configured to a separate a clot from a blood vessel wall. 
     The present invention also provides a method of removing an object from an interior lumen of an animal, the lumen having an interior wall forming the lumen. In some embodiments, the method includes: 
     a) providing a system comprising: i) a pull wire having a proximal end and a distal end; ii) a distal body attached to the pull wire, the distal body comprising a proximal end, a distal end, and a claw, the claw comprised of a plurality of memory metal strips, the distal body having a relaxed state wherein the distal body has a first height and width and a collapsed state wherein the distal body has a second height and width, the second height less than said first height, the second width less than said first width; and iii) a catheter having an interior, a proximal end leading to the interior and a distal end leading to the interior, the catheter comprised of a biocompatible material and configured to envelope the distal body when said distal body is in said collapsed state; 
     b) positioning the system in the lumen; 
     c) deploying the distal body from the distal end of the catheter; 
     d) allowing the height and width of said distal body to increase; and 
     e) moving the memory metal strips towards each other and the pull wire so as to capture the obstruction. Optionally, the claw and the memory metal strips are located at the proximal end of said distal body and the distal body is deployed distal to said object. Optionally, the proximal memory metal strips have a proximal end forming the proximal end of the claw and a distal end, and the method includes moving the proximal ends of the memory metal strips towards each other and the pull wire so as to capture the obstruction. Optionally, the distal body further comprises a proximal hub located in the distal body interior, and a distal hub located distal relative to the proximal hub, each of the memory metal strips has a proximal end and a distal end, each of the proximal ends of the memory metal strips is located proximal relative to the proximal hub, and the proximal ends of the memory metal strips are configured to move towards each other and towards the pull wire by moving the proximal hub distally and closer to the distal hub, and the proximal ends of the memory metal strips are configured to move away from each other and away from the pull wire by moving the proximal hub proximally and away from the distal hub, and the method further comprises moving the proximal hub distally and closer to the distal hub so as to capture the obstruction in the claw. Optionally, the interior lumen is an intracranial artery and the obstruction is a blood clot. Optionally, the method further comprises using the clot to move the proximal hub toward the distal hub and exert tension on the proximal memory metal strips. Optionally, the method further comprises using a tube to move the proximal hub toward the distal hub and exert tension on the proximal memory metal strips. 
     The present invention also provides a method of manufacturing a system for removing objects within an interior lumen of an animal. In some embodiments, the method includes: a) 
     providing a single tube comprised of a memory metal, the single tube having an exterior, a hollow interior, a wall separating the exterior from the hollow interior, a proximal portion comprising an aperture leading to the hollow interior, a distal portion comprising an aperture leading to the hollow interior, and a middle portion between the proximal portion and the distal portion; 
     b) cutting the wall of the middle portion with a laser; 
     c) removing the pieces of the middle portion cut by the laser to form a proximal tube, a middle portion comprising a plurality of memory metal strips attached to the proximal tube and a distal tube; 
     d) altering the shape of the middle portion; 
     e) allowing the middle portion to expand relative to the distal tube and the proximal tube; 
     f) cutting the memory metal strips to form a first segment comprising the proximal tube and a proximal segment of the memory metal strips, and a second segment comprising the distal tube and a distal segment of the memory metal strips; and 
     g) joining the proximal segments to the distal segments such that the distal segments form the proximal end of a distal body, such that the proximal tube is located inside an interior of said distal body, and such that the proximal tube is located distal relative to the proximal end. 
     Optionally, the method further includes placing a pull wire through the proximal tube such that the proximal tube is slideable along at least a segment of the pull wire. Optionally, the method further includes attaching the pull wire to the distal tube. Optionally, the step of joining the proximal segments to the distal segments comprises welding the proximal segments to the distal segments. Optionally, after the step of joining the proximal segments to the distal segments, the proximal end forms a claw comprised of between 2 and 4 memory metal strips, the claw memory metal strips configured to move towards each by moving said proximal tube distally and closer to the distal tube, and the claw memory metal strips configured to move away from each other by moving the proximal tube proximally and away from said distal tube. Optionally, the method further includes not altering the shape of the proximal and distal portions while altering the shape of the middle portion. Optionally, the method further includes cooling the proximal portion, the middle portion, and the distal portion after step D) and, after cooling, the proximal and distal portions have substantially the same size as the proximal and distal portions had prior to step A). Optionally, the method of allowing said middle portion to expand comprises heating the middle portion. Optionally, the method of altering the shape of the middle portion comprises using a mandrel. Optionally, the mandrel is tapered. Optionally, the proximal portion and the distal portion are not cut by the laser. Optionally, prior to cutting the memory metal tube, the memory metal tube has an outer diameter that is from about 0.011 inches to about 0.054 inches and an inner diameter that is from about 0.008 inches to about 0.051 inches. 
     In an alternate embodiment, the present disclosure provides a system for removing objects from an interior lumen of an animal that includes: 
     a pull wire having a proximal end and a distal end;
 
a distal body attached to the pull wire, the distal body comprising an interior, a proximal end, a distal end, a distal body length extending from the proximal end to the distal end, a proximal hub (preferably in the form of a tube) forming the proximal end of the distal body, a basket comprised of a plurality of cells formed by a plurality of basket strips, a plurality of proximal strips, and, optionally a distal hub (preferably in the form of a tube) forming a distal end of the basket, the basket comprising a basket interior, each proximal strip having a proximal end attached to the proximal hub, and a distal end attached to a cell, the distal body having a relaxed state wherein the distal body has a first height and a first width, and a collapsed state wherein the distal body has a second height and a second width, the second height less than the first height, the second width less than the first width; and
 
a catheter having an interior, a proximal end leading to the interior and a distal end leading to the interior, the catheter comprised of a biocompatible material and configured to envelope the distal body when the distal body is in the collapsed state,
 
wherein, in the relaxed state, the basket comprises a first pair of distal crowns not attached to another cell of the basket and pointing generally in the distal direction, the first pair of distal crowns located approximately the same distance from the proximal hub and approximately 180 degrees relative to each other (e.g., between about 150 degrees and about 180 degrees relative to each other), and further wherein the basket further comprises a second pair of distal crowns not attached to another cell of the basket and pointing generally in the distal direction, the second pair of distal crowns located distally relative to, and approximately 90 degrees relative to, the first pair of distal crowns (e.g., each distal crown of the second pair of distal crowns is located approximately 60 degrees to 90 degrees relative to a distal crown of the first pair of distal crowns), the distal crowns in the second pair of distal crowns located approximately the same distance from the proximal hub and further wherein each of the distal crowns in the first and second pair of distal crowns comprises an x-ray marker, the x-ray maker more visible under x-ray as compared to the basket strips when the distal body is located in a cranial blood vessel inside the body of a human and the x-ray is taken from outside the human&#39;s body. When it is said that the first pair of distal crowns are located approximately the same distance from the proximal hub, it will be understood that if one of the first pair of distal crowns is located X distance from the proximal hub, the other of the first pair of distal crowns is located X distance plus or minus (+/−) 3 mm from the proximal hub, more preferably X distance plus or minus (+/−) 0.5 mm from the proximal hub. Similarly, when it is said that the second pair of distal crowns are located approximately the same distance from the proximal hub, it will be understood that if one of the second pair of distal crowns is located Y distance from the proximal hub, the other of the first pair of distal crowns is located Y distance plus or minus (+/−) 3 mm from the proximal hub, more preferably Y distance plus or minus (+/−) 0.5 mm from the proximal hub. Optionally, instead of a distal hub, the basket includes an open distal end.
 
     Optionally, the x-ray markers are comprised of a material different than the material forming the basket strips. Optionally, in the relaxed state, the basket interior is substantially hollow. Optionally, in the relaxed state, the distal body does not have another x-ray marker that is located approximately the same distance from the proximal hub as the first pair of x-ray markers and the distal body does not have another x-ray marker that is located approximately the same distance from the proximal hub as the second pair of x-ray markers. In other words, the first and second pair of x-ray markers are the only markers their respective distances from the proximal hub. Optionally, each distal crown in the first and second pair of distal crowns forms part of an enlarged cell and further wherein the surface area of each enlarged cell in the relaxed state is greater than the surface area of each of the other individual cells of the basket and further wherein the enlarged cells are configured to allow a thrombus to pass therethrough and into the basket interior. Optionally, in the relaxed state, the distal body does not have another free distal-pointing crown that is located approximately the same distance from the proximal hub as the first pair of distal crowns and the distal body does not have another free distal-pointing crown that is located approximately the same distance from the proximal hub as the second pair of distal crowns. Optionally, the basket strips are comprised of a memory metal. Optionally, each of the distal crowns in the first pair and second pair of distal crowns curve radially inward toward the basket interior in the relaxed state, wherein the distal crowns of the first pair of distal crowns are configured to contact each other when an exterior, external compressive force (such as a thrombus) is exerted on a distal crown of the first pair of distal crowns when the distal body is in the relaxed state, and further wherein the distal crowns of the second pair of distal crowns are configured to contact each other when an exterior, external compressive force (such as a thrombus) is exerted on a distal crown of the second pair of distal crowns when the distal body is in the relaxed state. Optionally, the proximal hub is located approximately in the center of the first height and first width in the relaxed state. For example, preferably the proximal hub is located within 0.5 mm of the center of first width and the first height. Optionally, the catheter is comprised of a polymeric material (i.e., one or more polymeric materials such as silicone, PVC, latex rubber or braided nylon). Optionally, the pull wire is comprised of a biocompatible metallic material (e.g., a biocompatible metal or a biocompatible metal alloy). Optionally, the proximal end of a first proximal strip is located at least about 65 degrees (e.g., between about 65 and about 180 degrees) relative to the distal end of the first proximal strip, wherein the proximal end of a second proximal strip is located at least about 65 degrees (e.g., between about 65 and about 180 degrees) relative to the distal end of the second proximal strip, and further wherein the first and second proximal strips intersect adjacent and distal to the proximal hub (e.g., within about 0 and about 4 mm of the proximal hub). Optionally, each distal crown forms part of a cell that further comprises a proximal crown pointing generally in the proximal direction and connected to a memory metal strip (e.g., a proximal strip comprised of a memory metal or a basket strip comprised of a memory metal). In other words, the proximal crowns are not free. Optionally, the basket, the proximal hub and the proximal strips are comprised of a memory metal, wherein the proximal hub comprises a proximal end and a distal end, and further wherein the proximal strips are integral with the distal end of the proximal hub. Optionally, the length of the distal body from the proximal hub to the distal hub (not including any lead wire) is from about 20 mm to about 65 mm. Optionally, the system is used in a method of removing a blood clot from a blood vessel of an animal the method comprising the steps of: 
     a) providing the system;
 
b) positioning the system in the lumen;
 
c) deploying the distal body from the distal end of the catheter;
 
d) allowing the height and width of the distal body to increase;
 
e) irradiating the distal body with x-rays;
 
f) moving the clot into the distal basket interior; and
 
g) moving the distal body proximally out of the blood vessel.
 
     Optionally, the method further comprises irradiating the distal body with x-rays at at least two different angles. Optionally, at least one x-ray marker attached to the distal crowns is distal to the clot when the distal body is deployed from the distal end of the catheter. Optionally, the method further comprises applying contrast dye proximally and distally to the clot. Optionally, the method further comprises providing a suction catheter having a proximal end and a distal end, and attaching the distal end of the suction catheter to the clot by applying suction to the suction catheter. Optionally, the method further comprises aspirating by hand a pre-determined volume of fluid from the suction catheter using a syringe and then locking the syringe at the pre-determined volume. Optionally, the method further comprises delivering the suction catheter adjacent to the clot by advancing the catheter over the pull wire. 
     In yet another embodiment, the system includes: 
     a pull wire having a proximal end and a distal end;
 
a distal body attached to the pull wire, the distal body comprising an interior, a proximal end, a distal end, a distal body length extending from the proximal end to the distal end, a proximal hub (preferably in the form of a tube) forming the proximal end of the distal body, a basket comprised of a plurality of cells formed by a plurality of basket strips, a plurality of proximal strips, and optionally a distal hub (preferably in the form of a tube) forming a distal end of the basket, the basket comprising a basket interior, each proximal strip having a proximal end attached to the proximal hub, and a distal end attached to a cell, the distal body having a relaxed state wherein the distal body has a first height and a first width, and a collapsed state wherein the distal body has a second height and a second width, the second height less than the first height, the second width less than the first width; and
 
a catheter having an interior, a proximal end leading to the interior and a distal end leading to the interior, the catheter comprised of a biocompatible material and configured to envelope the distal body when the distal body is in the collapsed state,
 
wherein, in the relaxed state, the basket comprises a first pair of distal crowns not attached to another cell of the basket and pointing generally in the distal direction, the first pair of distal crowns located approximately the same distance from the proximal hub and approximately 180 degrees relative to each other (e.g., between about 150 degrees and about 180 degrees relative to each other), and further wherein the basket further comprises a second pair of distal crowns not attached to another cell of the basket and pointing generally in the distal direction, the second pair of distal crowns located distally relative to, and approximately 90 degrees relative to, the first pair of distal crowns (e.g., each distal crown of the second pair of distal crowns is located approximately 60 degrees to 90 degrees relative to a distal crown of the first pair of distal crowns), the distal crowns in the second pair of distal crowns located approximately the same distance from the proximal hub, wherein each distal crown of the first and second pair of distal crowns form a cell, each cell further comprising a proximal crown pointing generally in the proximal direction and connected to a memory metal strip, wherein each of the distal crowns in the first pair and second pair of distal crowns curve radially inward toward the basket interior in the relaxed state, wherein the distal crowns of the first pair of distal crowns are configured to contact each other when an exterior, external compressive force (e.g., a thrombus) is exerted on a distal crown of the first pair of distal crowns when the distal body is in the relaxed state, and further wherein the distal crowns of the second pair of distal crowns are configured to contact each other when an exterior, external compressive force (e.g., a thrombus) is exerted on a distal crown of the second pair of distal crowns when the distal body is in the relaxed state. When it is said that a proximal crown pointing generally in the proximal direction and is connected to a memory metal strip, it is meant that the proximal crown is either connected to a basket strip or a proximal strip comprised of a memory metal (e.g., nitinol). When it is said that the first pair of distal crowns are located approximately the same distance from the proximal hub, it will be understood that if one of the first pair of distal crowns is located X distance from the proximal hub, the other of the first pair of distal crowns is located X distance plus or minus (+/−) 3 mm from the proximal hub, more preferably X distance plus or minus (+/−) 0.5 mm from the proximal hub. Similarly, when it is said that the second pair of distal crowns are located approximately the same distance from the proximal hub, it will be understood that if one of the second pair of distal crowns is located Y distance from the proximal hub, the other of the first pair of distal crowns is located Y distance plus or minus (+/−) 3 mm from the proximal hub, more preferably Y distance plus or minus (+/−) 0.5 mm from the proximal hub. Optionally, instead of a distal hub, the basket includes an open distal end.
 
     Optionally, the proximal hub is located approximately in the center of the first height and first width in the relaxed state. For example, preferably the proximal hub is located within 0.5 mm of the center of first width and the first height. Optionally, the catheter is comprised of a polymeric material (i.e., one or more polymeric materials such as silicone, PVC, latex rubber or braided nylon). Optionally, the pull wire is comprised of a biocompatible metallic material (e.g., a biocompatible metal or a biocompatible metal alloy). Optionally, in the relaxed state, the basket interior is substantially hollow. Optionally, the proximal end of a first proximal strip is located at least about 65 degrees (e.g., between about 65 and about 180 degrees) relative to the distal end of the first proximal strip, wherein the proximal end of a second proximal strip is located at least about 65 degrees (e.g., between about 65 and about 180 degrees) relative to the distal end of the second proximal strip, and further wherein the first and second proximal strips intersect adjacent and distal to the proximal hub (e.g., within about 0 mm and about 4 mm of the proximal hub). Optionally, each distal crown in the first and second pair of distal crowns forms part of an enlarged cell and further wherein the surface area of each enlarged cell in the relaxed state is at least twice as large as the surface area of each other individual cell of the basket and further wherein the enlarged cells are configured to allow a thrombus to pass therethrough and into the basket interior. Optionally, the pull wire is attached to the proximal hub. Optionally, the basket, the proximal hub and the proximal strips are comprised of a memory metal, wherein the proximal hub comprises a proximal end and a distal end, and further wherein the proximal strips are integral with the distal end of the proximal hub. Optionally, the distal body further comprises a lead wire extending distally from the distal hub, the lead wire having a length of from about 3 mm to about 10 mm. Optionally, the distal hub, the proximal hub, and the basket are comprised of a nitinol having the same material composition and further wherein the proximal and the distal hubs are tubular and generally cylindrical in shape and each has an outer diameter and an inner diameter, the inner diameter forming apertures of the proximal and distal hubs and further wherein the outer diameters of the proximal and distal hubs are substantially the same size and further wherein the inner diameters of the proximal and distal hubs are substantially the same size. Optionally, the length of the distal body from the proximal hub to the distal hub (not including any lead wire) is from about 20 mm to about 65 mm. 
     Optionally, the system is used in a method of removing a blood clot from a blood vessel of an animal the method comprising the steps of: 
     a) providing the system;
 
b) positioning the system in the lumen;
 
c) deploying the distal body from the distal end of the catheter;
 
d) allowing the height and width of the distal body to increase;
 
e) irradiating the distal body with x-rays;
 
f) moving the clot into the distal basket interior; and
 
g) moving the distal body proximally out of the blood vessel.
 
     Optionally, the method further comprises irradiating the distal body with x-rays at at least two different angles. 
     In other embodiments the present disclosure provides a system for removing objects within an interior lumen of an animal, the system comprising: 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from the proximal end to the distal end; 
     a coaxial sheath having a hollow interior, an open proximal end leading to the interior, and an open distal end leading to the interior, the coaxial sheath enveloping the pull wire, the coaxial sheath slideable along at least a segment of the pull wire; 
     a distal basket comprising an interior, a proximal end, a distal end, a distal basket length extending from the distal basket proximal end to the distal basket distal end, a distal basket height perpendicular to the distal basket length, a plurality of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, and a plurality of distal cells distal to the proximal cells; 
     a plurality of proximal strips, each proximal strip having a proximal end extending from the coaxial sheath, a distal end attached to a proximal crown of a proximal cell and a length extending from the proximal end to the distal end; and 
     a catheter having a hollow interior, a proximal end leading to the interior and a distal end leading to the interior, the catheter comprised of a biocompatible material, 
     the distal basket comprised of a memory metal and having: 
     a relaxed state in which the distal end of the coaxial sheath is located at a first position along the pull wire, the first position located a first distance proximal to the proximal crowns, and in which the distal basket, as measured at the proximal-most crown, has a first height, 
     a proximal collapsed state in which the distal end of the coaxial sheath is located at a second position along the pull wire, the second position located a second distance proximal to the proximal crowns, and in which the distal basket, as measured at the proximal-most crown, has a second height, the second distance greater than the first distance, the second height less than the first height, and 
     a distal collapsed state in which the distal end of the coaxial sheath is located at a third position along the pull wire, the third position distal to the proximal crowns and located in the basket interior, and in which the distal basket, as measured at the proximal-most crown, has a third height, the third height less than the first height, 
     wherein the catheter is configured to envelope the distal basket when the distal basket is in the proximal collapsed state; 
     wherein the distal basket is configured to move from the relaxed state to the proximal collapsed state by moving the distal end of the coaxial sheath proximally to the second position while keeping the distal basket at a fixed location along the pull wire; and 
     wherein the distal basket is configured to move from the relaxed state to the distal collapsed state by moving the distal end of the coaxial sheath distally to the third position while keeping the distal basket at a fixed location along the pull wire. 
     Optionally, each proximal crown comprises a proximal tip and further wherein each proximal strip is configured to cover a proximal tip when the distal basket is in the distal collapsed state. Optionally, each proximal crown comprises an eyelet and further wherein each proximal strip passes through an eyelet. Optionally, the distal end of each proximal strip comprises a loop attaching the proximal strip to an eyelet. Optionally, each proximal crown has an interior surface facing the distal basket interior and an exterior surface opposite the interior surface and further wherein each proximal strip contacts an exterior surface of a proximal crown in the proximal collapsed state and in the distal collapsed state. Optionally, the pull wire extends through the distal basket interior and further wherein the proximal crowns are configured to move towards each other and towards the pull wire when the distal basket moves from the relaxed state to the distal collapsed state and when the distal basket moves from the relaxed state to the proximal collapsed state. Optionally, the proximal crowns are configured to remain a fixed distance from the distal end of the distal basket when the distal basket moves from the relaxed state to the distal collapsed state. Optionally, the coaxial sheath is a braided catheter comprised of a plurality of braids, and further wherein the proximal segments of the braids are wound together to form the braided catheter and further wherein an unwound distal segment of each braid forms a proximal strip. Optionally, at least one proximal crown further comprises an x-ray marker. Optionally, the proximal ends of the proximal strips are integral with the coaxial sheath. Optionally, the proximal ends of the proximal strips are attached to the coaxial sheath. Optionally, the system comprises between two and four proximal strips and the proximal strips are spaced substantially evenly apart. Optionally, the proximal strips have a length of from about 5 millimeters to about 40 millimeters in the relaxed state. Optionally, the pull wire extends through the basket interior from the distal basket proximal end to the distal basket distal end. Optionally, the coaxial sheath interior has a size and shape, and further wherein the size and shape of the coaxial sheath interior are configured to prevent a segment of the pull wire located in the basket interior and distal relative to the distal end of the coaxial sheath from moving through the coaxial sheath interior. Optionally, the distal end of the distal basket comprises a distal tube having an open proximal end and an open distal end, the distal tube comprised of a memory metal. Optionally, the distal basket and the distal were prepared from the same memory metal tube. Optionally, the second and third position along the pull wire each comprise an x-ray marker. Optionally, the distal tube is attached to the pull wire such that the distal tube is not slideable along the pull wire. Optionally, all proximal crowns of the proximal cells are attached to a proximal strip. Optionally, the distal basket further comprises a lead wire extending distally from the distal basket. Optionally, the proximal strips and the distal basket have a different material composition. Optionally, the proximal strips are comprised of a polymer. Optionally, the polymer is selected from the group consisting of fluorinated ethylene propylene, polytetrafluoroethylene, and tetrafluoroethylene. Optionally, the proximal strips are comprised of a material selected from the group consisting of plastic, rubber, nylon, suture material, and braided catheter material. 
     Optionally, the system is used in a method of removing a clot from a blood vessel of an animal, the blood vessel having an interior wall forming the blood vessel, the method comprising the steps of: 
     a) providing the system, wherein the coaxial sheath is located in the catheter interior and the distal basket is located in the catheter interior in a collapsed state; 
     b) positioning the catheter in the blood vessel; 
     c) deploying the distal basket from the distal end of the catheter so that the proximal crowns of the proximal cells are distal to the clot; 
     d) allowing the distal basket to move to the relaxed state; 
     e) moving the coaxial sheath distally to a fourth position, the fourth position located distally beyond the proximal crowns and in the basket interior but proximal to the third position (this third position is not sufficiently distal to the proximal crowns to place tension on the proximal strips; thus, the crowns do not begin to move towards each other and the pull wire); 
     f) capturing the clot in the distal basket interior; 
     g) moving the coaxial sheath further distally into the basket interior (i.e., to or near) the third position so that the distal basket height, as measured at the proximal-most crown, decreases and the proximal crowns move toward each other and the pull wire; and 
     h) moving the system proximally out of the blood vessel. 
     In still further embodiments, the present disclosure provides a system for removing objects within an interior lumen of an animal, the system comprising: 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from the proximal end to the distal end; 
     a coaxial sheath having an open proximal end and an open distal end, the coaxial sheath enveloping the pull wire, the coaxial sheath slideable along at least a segment of the pull wire; 
     a distal basket comprising an interior, a proximal end, a distal end, a distal basket length extending from the distal basket proximal end to the distal end, a distal basket height perpendicular to the distal basket length, a plurality of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, and a plurality of distal cells distal to the proximal cells; 
     a plurality of proximal strips, each proximal strip having a proximal end extending from the coaxial sheath, a distal end attached to a crown of a proximal cell and a length extending from the proximal end to the distal end; and 
     a catheter having a hollow interior, a proximal end leading to the interior and a distal end leading to the interior, the catheter comprised of a biocompatible material, 
     the distal basket comprised of a memory metal, 
     wherein each proximal crown of each proximal cell comprises an eyelet and further wherein each proximal strip passes through an eyelet. 
     The present disclosure also provides additional modular, easy-to-manufacture platform of systems for retrieving hard clots and other objects in animal lumens. In some embodiments, the system includes a proximal tube, a distal tube, and a plurality of memory metal strips between the proximal and distal tubes. The plurality of memory metal strips form a wide range of basket designs. Preferably, the proximal tube, memory metal strips, and distal tube are derived from a standard, off-the-shelf single tube of memory metal (e.g., a memory metal alloy such as nitinol), with the proximal tube and distal tube having the same inner diameter and outer diameter as the native tube from which they were derived and with the basket formed by cutting the middle portion of the native tube and expanding and shape-setting this cut portion. Preferably, the proximal tube and distal tube have an outer diameter that is from about 0.02 inches to about 0.03 inches (e.g., about 0.027 inches) so that the device fits inside a standard microcatheter and an inner diameter that is from about 0.01 inches to about 0.02 inches. Preferably, there are no welded parts between the proximal tube and distal tube, which makes the system easy and cheap to reliably manufacture. The system also includes one or more catheters for deploying the system, a pull wire that passes through the hollow interior of the proximal tube, and a coaxial tube. Preferably, the system includes two catheters—a guide catheter and a microcatheter. The coaxial tube envelopes the pull wire, is slideable along at least a segment of the pull wire, and is attached to the proximal hub. The coaxial tube allows a user to move the proximal hub toward and away from the distal hub while keeping the distal hub stationary. Movement of the proximal hub toward and away from the distal hub causes conformational changes in the basket, including (depending on the basket design and the location of the proximal tube), collapsing the basket, expanding the basket, strengthening the basket, and moving the basket around the clot. The plurality of memory metal strips attached to the proximal hub include a plurality of proximal tether memory metal strips, which have a proximal end attached to the distal end of the proximal tube. The length and thickness of the proximal tether memory metal strips vary in the different embodiments described herein, which allows the surgical user to select from the various embodiments in the platform based on the features needed for the particular operation (e.g., vessel anatomy and hardness of the clot). 
     In some embodiments, the present disclosure provides a method of manufacturing a system for removing objects within an interior lumen of an animal that includes: 
     a) providing a single tube comprised of a memory metal, the single tube having an exterior, a hollow interior, a wall separating the exterior from the hollow interior, a proximal portion comprising an aperture leading to the hollow interior, a distal portion comprising an aperture leading to the hollow interior, and a middle portion between the proximal portion and the distal portion;
 
b) cutting the wall of the middle portion with a laser;
 
c) removing the pieces of the middle portion cut by the laser to form a basket system comprising a proximal tube comprising a hollow interior extending through said proximal tube, said proximal tube having a proximal end and a distal end, a distal tube comprising a hollow interior extending through said distal tube, and a middle portion located between said proximal tube and said distal tube and comprising a plurality of proximal tether memory metal strips, each proximal tether memory metal strip having a proximal end attached to the distal end of the proximal tube and a distal end;
 
d) altering the shape of the middle portion;
 
e) allowing the middle portion to expand relative to the distal tube and the proximal tube to form a basket that includes a plurality of cells;
 
f) optionally, inserting a pull wire through said proximal tube interior so that said proximal tube is slideable along at least a portion of said pull wire, said pull wire having a proximal end and a distal end; and
 
g) optionally, attaching said pull wire to said distal hub.
 
     In other embodiments, instead of steps f) and g) noted above, the method includes inserting a pull wire comprising a proximal end, a distal end, a stop located adjacent to said distal end, through said proximal tube interior, said stop having a width and/or height that is greater than said proximal tube interior, said stop located distal relative to said proximal tube interior, so that said proximal tube is slideable distally until the proximal hub reaches said stop, said pull wire not contacting said distal tube. In such embodiments, the pull wire does not contact the distal hub. Rather in these embodiments, the method further includes attaching a leader wire to said distal tube 
     In some embodiments, either of the above methods further include h) providing a coaxial tube, said coaxial tube comprising a hollow interior receiving said pull wire, a proximal end, and a distal end, and i) attaching said distal end of said coaxial tube to said proximal tube. In some embodiments, the method of attaching said distal end of said coaxial tube to said proximal tube comprises welding said distal end of said coaxial tube to said proximal tube. In other embodiments, the method of attaching said distal end of said coaxial tube to said proximal tube comprises shrink wrapping said distal end of said coaxial tube to said proximal tube. In other embodiments, the method of attaching said distal end of said coaxial tube to said proximal tube comprises gluing said distal end of said coaxial tube to said proximal tube. 
     Optionally, after step e, the basket further comprises a row of proximal cells, each proximal cell defined by a plurality of memory metal strips and comprising a proximal crown located at a proximal end of the cell and pointing in the proximal direction and a distal crown located at a distal end of the cell and pointing in the distal direction and further wherein each of said proximal crowns of said proximal cells is attached to a distal end of a proximal tether memory metal strip. Optionally, after step e, the basket further comprises a row of distal cells located distal to said proximal cells and connected to said distal crowns of said proximal cells, each distal cell defined by a plurality of memory metal strips and comprising a proximal crown located at a proximal end of the cell and pointing in the proximal direction and a distal crown located at a distal end of the cell and pointing in the distal direction, and further wherein the number of distal cells is twice the number of proximal cells. Optionally, after step e, the basket further comprises a row of distal crowns distal to said proximal crowns and pointing in the distal direction and further wherein the number of distal crowns in said row is twice the number of proximal crowns attached to said proximal tether memory metal strip. 
     Optionally, after step e, the basket system further comprises a row of strut memory metal strips, each strut memory metal strip having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, the basket comprises no welded components and said proximal tether memory metal strips are integral with said proximal cell crowns. 
     Optionally, after step e, the basket system comprises between two and four proximal tether memory metal strips. Optionally, the method further comprises not altering the shape of the proximal and distal portions while altering the shape of the middle portion. Optionally, the method further comprises cooling the proximal portion, the middle portion, and the distal portion after step D) and, after cooling, the proximal and distal portions have substantially the same size as the proximal and distal portions had prior to step A). Optionally, the method of allowing said middle portion to expand comprises heating the middle portion. Optionally, the method of altering the shape of the middle portion comprises using a mandrel. Optionally, the mandrel is tapered. Optionally, the proximal portion and the distal portion are not cut by the laser. Optionally, prior to cutting the memory metal tube, the memory metal tube has an outer diameter that is from about 0.011 inches to about 0.054 inches and an inner diameter that is from about 0.008 inches to about 0.051 inches. Optionally, after step e), the proximal tube and distal tube have an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally, the method further includes placing said basket inside a catheter comprised of a biocompatible material. Optionally, the method further includes the steps of placing the basket inside a lumen of an animal and using the basket to retrieve an object located inside said lumen. 
     The present disclosure also provides several systems for removing objects within an interior lumen of an animal. In some embodiments, the system includes: 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end; 
     a distal basket attached to said pull wire, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a proximal hub located at said proximal end of the distal basket, said proximal hub comprising a hollow interior, said pull wire passing through said proximal hub hollow interior, said proximal hub slideable along at least a segment of the pull wire, a plurality of proximal tether memory metal strips, a plurality of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, each proximal tether memory metal strip having a proximal end attached to said proximal hub, a distal end attached to a crown of a proximal cell and a length extending from said proximal end to said distal end, a plurality of distal cells distal to the proximal cells, and a distal hub located at said distal end of said distal basket and comprising a hollow interior, 
     said distal basket having 
     a relaxed state in which said proximal hub is located a first distance proximal to said proximal crowns and wherein said distal basket has a first height, as measured at the proximal-most crown, 
     a gaping state in which said proximal hub is located a second distance from said proximal crowns and wherein has a second height, as measured at the proximal-most crown, said second height greater than said first height, said second distance less than said first distance, 
     a proximal collapsed state in which said proximal hub is located a third distance proximal to said proximal crowns and wherein said distal basket has a third height, as measured at the proximal-most crown, said third distance greater than said first distance, said third height less than said first height, 
     a catheter having a hollow interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said distal basket when said distal basket is in said proximal collapsed state; 
     wherein said distal basket is configured to move from said relaxed state to said gaping state by moving said proximal hub distally relative to said distal hub; and 
     wherein said distal basket is configured to move from said expanded state to said proximal collapsed state by moving said proximal hub proximally relative to said distal hub. 
     In some embodiments, the proximal tether memory metal strips have a thickness of between about 25% and 75% of the memory metal strips forming the proximal cell of the distal basket. In these embodiments, translation of the proximal hub toward the stationary distal hub deforms the tethers instead of the distal basket. In other embodiments, the proximal tether memory metal strips are as thick or thicker than the memory metal strips forming the proximal cells of the distal basket (e.g., between about 100% and 175% of the thickness of the memory metal strips forming the proximal cells of the basket). In these embodiments with thicker proximal tether memory metal strips, the proximal tether memory metal strips resist deforming when the proximal hub is translated distally toward the stationary distal hub and instead the proximal tether memory metal strips are bowed out laterally, dissecting through or around the clot and centering, buttressing and strengthening the opening of the basket. Generally, in both embodiments, moving the proximal hub towards the distal hub when the basket is in the relaxed state causes the proximal crowns of the proximal cells to move apart from each other, thereby expanding the opening of the distal basket. Preferably, in the embodiments with the thin tethers, in the relaxed state, the tethers have a length of from about 3 mm to about 10 mm, and in the embodiments with the thick tethers, the tethers have a length of from about 10 mm to about 20 mm. 
     Optionally, the distal basket further comprises a distal collapsed state in which said proximal hub is located distal to said proximal crowns and wherein said distal basket has a fourth height, as measured at the proximal-most crown, said fourth height less than said first height and, wherein said catheter is configured to envelope said distal basket when said distal basket is in said distal collapsed state, and further wherein said distal basket is configured to move from said gaping state to said distal collapsed state by moving said proximal hub distally relative to said distal hub. Optionally, the system further includes a coaxial tube, said coaxial tube configured to be received in said catheter, said coaxial tube having a proximal end, a distal end attached to said proximal hub, and a hollow interior, said pull wire passing through said coaxial tube hollow interior, said coaxial tube slideable along at least a segment of said pull wire. In some embodiments with the thin proximal memory metal strips, the combined length of two of said proximal tether memory metal strips is within about 2 mm of said second height. In other embodiments with the thin proximal memory metal strips, the combined length of two of said proximal tether memory metal strips is within about 2 mm of said second height multiplied by a factor of two. Optionally, said pull wire extends from said distal basket proximal end to said distal basket distal end. Optionally, said pull wire is not in contact with said distal hub. Optionally, in said gaping state, said proximal hub is located parallel to said proximal crown. Optionally, said pull wire and said proximal hub are offset from the center of the distal basket height, as measured at the proximal-most crown. Optionally, all proximal crowns of said proximal cells are attached to a proximal tether memory metal strip. In other embodiments, the system has four proximal cells, each proximal cell having a proximal crown, and not all (e.g., only two) of the proximal crowns are attached to a proximal tether memory metal strip. Optionally, said distal basket further comprises a plurality of strut memory metal strips and plurality of distal cells defined by a plurality of distal memory metal strips, said distal cells comprising a proximal crown located at a proximal end of said distal cells and a distal crown located at a distal end of said distal cells, said strut memory metal strips having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, the distal basket comprises between two and four proximal tether memory metal strips. Optionally, said proximal memory metal strips are integral with said proximal hub. Optionally, said proximal hub is a tube, wherein said interior of said proximal hub has a size and shape, and further wherein said size and shape of said proximal hub interior are configured to prevent a segment of said pull wire distal relative to said proximal hub from moving through proximal hub interior. Optionally, said distal hub is a tube. Optionally, said distal hub is attached to said pull wire such that said distal hub is not slideable along said pull wire. Optionally, said distal basket further comprises a lead wire extending distally from said distal hub. Optionally, said distal hub, said proximal hub, and said basket are comprised of a nitinol having the same material composition. Optionally, said distal basket further comprises an x-ray marker. Optionally, said proximal and said distal hubs are generally cylindrical in shape and each has an outer diameter and an inner diameter, the inner diameter forming apertures of the proximal and distal hubs and further wherein the outer diameters of the proximal and distal hubs are substantially the same size and further wherein the inner diameters of the proximal and distal hubs are substantially the same size. Optionally, the outer diameters of the proximal and distal hubs are from about 0.011 inches to about 0.054 inches, and further wherein the inner diameters of the proximal and distal hubs are from about 0.008 inches to about 0.051 inches. Optionally, the proximal tube and distal tube have an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally, the pull wire is generally cylindrical and further wherein the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Optionally, the first height of the distal basket is between about 2 millimeters and about 8 millimeters. Optionally, said proximal tether memory metal strips rotate about said pull wire longitudinal axis such that a distal end of a proximal tether memory metal strip is located between about 90 and about 270 degrees relative to said proximal end of the same proximal tether memory metal strip. 
     The present disclosure also provides a method of removing an object from an interior lumen of an animal, said lumen having an interior wall forming said lumen. In some embodiments, the method includes: 
     a) providing the system described above;
 
b) positioning the system in said lumen, said basket located in said catheter in a collapsed state;
 
c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction;
 
d) allowing said distal basket to move to said relaxed state;
 
e) moving said proximal hub distally relative to said distal hub so that said distal basket height, as measured at the proximal-most crown, increase;
 
f) moving said distal basket over said obstruction; and
 
g) removing said distal basket and said obstruction from said lumen.
 
     Optionally, the interior lumen is an intracranial artery and said obstruction is a blood clot. Optionally, the method further comprises using said blood clot to move said proximal hub distally relative to said distal hub and allow said distal basket to move to said gaping state. Optionally, the method further comprises using a coaxial tube to push said proximal hub distally relative to said distal hub and allow said distal basket to move to said gaping state. Optionally, the method further includes, after step e, moving said proximal hub relative to said distal hub so that said distal basket height, as measured at the proximal-most crown, decrease. Optionally, after step e, said pull wire and said proximal hub are offset with respect to the center of said distal basket height, as measured at the proximal-most crown, as measured at the proximal-most crown, and the center of said lumen. 
     The present disclosure also provides a system for removing objects within an interior lumen of an animal, the system comprising: 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end; 
     a proximal basket attached to said pull wire, said proximal basket comprising a proximal end, a distal end, a proximal basket length extending from said proximal basket proximal end to said distal end, a proximal basket height perpendicular to said proximal basket length and said pull wire longitudinal axis, a proximal tube located at said proximal end of the proximal basket, said proximal tube comprising a hollow interior, said pull wire passing through said hollow interior and said proximal tube slideable along at least a segment of said pull wire, a plurality of rows of cells, each cell defined by a plurality of memory metal strips, each cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, 
     a distal basket attached to said pull wire, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a distal tube located at said distal end of the distal basket, said distal tube comprising a hollow interior, a plurality of rows of cells, each cell defined by a plurality of memory metal strips, each cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, 
     a plurality of tether memory metal strips, each tether memory metal strip having a proximal end attached to a distal crown of a cell located at the distal end of said proximal basket and a distal end attached to a proximal crown of a cell located at the proximal end of said distal basket, 
     said proximal basket having 
     a relaxed state wherein said proximal basket has a first height, as measured at the distal-most crown, and said proximal hub is located a first distance proximal to said distal hub; 
     a collapsed state wherein said proximal basket has a second height, as measured at the distal-most crown, said second height less than said first height; 
     a gaping state wherein said proximal basket has a third height, as measured at the distal-most crown, and said proximal hub is located a second distance proximal to said distal hub, said third height greater than said first height and said second distance less than said first distance, said proximal basket configured to move from said expanded state to said gaping state by pushing said proximal tube distally relative to said distal tube; 
     said distal basket having 
     a relaxed state wherein said distal basket has a first height and 
     a collapsed state wherein said distal basket has a second height, said second height less than said first height, and 
     a catheter having an interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said distal and said proximal basket when said baskets are in said collapsed state. 
     Optionally, said proximal tether memory metal strips rotate about said pull wire longitudinal axis such that a distal end of a proximal tether memory metal strip is located between about 90 and about 270 degrees relative to said proximal end of the same proximal tether memory metal strip. 
     In some embodiments, the system does not include a proximal hub and the system includes soft cords in place of or in addition to the proximal memory metal strips. For example, in one embodiment, the system includes: 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end;
 
a coaxial tube having a proximal end, a distal end and a hollow interior, said pull wire passing through said coaxial tube hollow interior, said coaxial tube slideable along at least a segment of said pull wire;
 
a distal basket attached to said pull wire and said coaxial tube, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a plurality of cords, a plurality of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, each cord having a proximal end attached to said coaxial tube, a distal end attached to a crown of a proximal cell and a length extending from said proximal end to said distal end, a plurality of distal cells distal to the proximal cells, and a distal hub located at said distal end of said distal basket and comprising a hollow interior,
 
said distal basket having
 
a relaxed state in which said coaxial tube is located a first distance proximal to said proximal crowns and wherein said distal basket, as measured at the proximal-most crown, has a first height,
 
a proximal collapsed state in which said coaxial tube is located a second distance proximal to said proximal crowns and wherein said distal basket, as measured at the proximal-most crown, has a second height, said second distance greater than said first distance, said second height less than said first height,
 
a catheter having a hollow interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said coaxial tube and said distal basket when said distal basket is in said proximal collapsed state; wherein said distal basket is configured to move from said relaxed state to said proximal collapsed state by moving said coaxial tube proximally relative to said distal hub.
 
     Optionally, the distal basket further comprises a distal collapsed state in which said coaxial tube is located distal to said proximal crowns and wherein said distal basket, as measured at the proximal-most crown, has a third height, said third height less than said first height, wherein said catheter is configured to envelope said distal basket when said distal basket is in said distal collapsed state, and further wherein said distal basket is configured to move from said relaxed state to said distal collapsed state by moving said coaxial tub distally relative to said distal hub. Optionally said cord is comprised of a material selected from the group consisting of plastic, rubber, nylon, suture material, braided catheter material, platinum coils, and ultrafine nitinol. Optionally, said cords are integral with said coaxial sheath. Optionally, said cords are glued to said coaxial sheath. Optionally, said cords are shrink wrapped to said coaxial sheath. Optionally, said cords have a thickness of about 0.004 to about 0.1 inches (more preferably, from about 0.004 to 0.018 inches). Optionally, said cords in said relaxed state, have a length of about 3 to about 20 mm. Optionally, said pull wire extends from said distal basket proximal end to said distal basket distal end and said pull wire is attached to said distal hub. Optionally, all proximal crowns of said proximal cells are attached to a cord. Optionally, the basket comprises four proximal cells, each proximal cell having a proximal crown, and not all (e.g., only two) of the proximal crowns are attached to a cord. Optionally, said distal basket further comprises a plurality of strut memory metal strips and plurality of distal cells defined by a plurality of distal memory metal strips, said distal cells comprising a proximal crown located at a proximal end of said distal cells and a distal crown located at a distal end of said distal cells, said strut memory metal strips having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, the distal basket comprises between two and four cords. Optionally, said distal hub is attached to said pull wire such that said distal hub is not slideable along said pull wire. Optionally, said distal basket further comprises a lead wire extending distally from said distal hub. Optionally, said distal hub and said basket are comprised of a nitinol having the same material composition. Optionally, said distal basket and/or said coaxial tube further comprises an x-ray marker. Optionally, said distal hub is generally cylindrical in shape and has an outer diameter and an inner diameter, the inner diameter forming the aperture of the distal hub and further wherein the outer diameter of the distal hub from about 0.011 inches to about 0.054 inches, and further wherein the inner diameter of the distal hub is from about 0.008 inches to about 0.051 inches. Optionally, the distal tube has an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally, the pull wire is generally cylindrical and further wherein the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Optionally, the first height of the distal basket, as measured at the proximal-most crown, is between about 2 millimeters and about 8 millimeters. Optionally, said cords are soft. 
     In some embodiments, the present disclosure provides a method of removing an object from an interior lumen of an animal, said lumen having an interior wall forming said lumen, the method comprising the steps of: 
     a) providing the system described above;
 
b) positioning the system in said lumen, said basket located in said catheter in a collapsed state;
 
c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction;
 
d) allowing said distal basket to move to said relaxed state;
 
e) moving said coaxial tube distally relative to said distal hub so that said coaxial tube moves distally to the proximal-most crown;
 
f) moving said distal basket, said pull wire and said coaxial tube proximally so that said distal basket moves over said obstruction;
 
g) moving said coaxial sheath distally relative to said distal hub so that said distal basket height, as measured at the proximal-most crown, decreases and said coaxial tube is closer to said distal hub as compared to the proximal-most crown; and
 
h) removing said distal basket and said obstruction from said lumen.
 
     In other embodiments, the method includes 
     a) providing the system described above;
 
b) positioning the system in said lumen, said basket located in said catheter in a collapsed state;
 
c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction;
 
d) allowing said distal basket to move to said relaxed state;
 
e) moving said coaxial tube distally relative to said distal hub so that said coaxial tube moves distally to the proximal-most crown;
 
f) moving said distal basket, said pull wire and said coaxial tube proximally so that said distal basket moves over said obstruction;
 
g) moving said coaxial sheath proximally relative to said distal hub so that said distal basket height, as measured at the proximal-most crown, decreases;
 
h) moving said catheter distally relative to said distal hub so that said catheter re-sheaths said coaxial sheath and partially re-sheaths said cords, thereby decreasing said distal basket height, as measured at the proximal-most crown;
 
i) removing said distal basket and said obstruction from said lumen.
 
     Optionally, said interior lumen is an intracranial artery and said obstruction is a blood clot. 
     In other embodiments that do not include a proximal hub, the system includes 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end;
 
a coaxial tube having a proximal end, a distal end and a hollow interior, said pull wire passing through said coaxial tube hollow interior, said coaxial tube slideable along at least a segment of said pull wire;
 
a distal basket attached to said pull wire and said coaxial tube, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a plurality of proximal tether memory metal strips, a plurality of cords, a plurality of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, each proximal tether memory metal strip having a proximal end attached to said coaxial tube and a distal end, each cord having a proximal end attached to a distal end of a proximal tether memory metal strip and a distal end attached to a crown of a proximal cell and a length extending from said proximal end to said distal end, and a plurality of distal cells distal to the proximal cells, and a distal hub located at said distal end of said distal basket and comprising a hollow interior,
 
said distal basket having
 
a relaxed state in which said distal basket, as measured at the proximal-most crown, has a first height,
 
a collapsed state in which said distal basket, as measured at the proximal-most crown, has a second height, said second height less than said first height,
 
a catheter having a hollow interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said coaxial tube and said distal basket when said distal basket is in said collapsed state.
 
     Optionally, said cord is comprised of a material selected from the group consisting of plastic, rubber, nylon, suture material, braided catheter material, platinum coils and ultrafine nitinol. Optionally, said proximal tether memory metal strips are integral with said coaxial sheath. Optionally, said cords are glued to said proximal tether memory metal strips. Optionally, said cords are shrink wrapped to said proximal tether memory metal strips. Optionally, said cords have a thickness of from about 0.004 and about 0.1 inches (more preferably about 0.004 to about 0.018 inches) and said cords have a length of from about 3 mm to about 10 mm in said relaxed state. Optionally, said pull wire extends from said distal basket proximal end to said distal basket distal end and said pull wire is attached to said distal hub. Optionally, all proximal crowns of said proximal cells are attached to a cord. Optionally, the basket comprises four proximal cells, each proximal cell having a proximal crown, and not all (e.g., only two) of the proximal crowns are attached to a cord. Optionally, said distal basket further comprises a plurality of strut memory metal strips and plurality of distal cells defined by a plurality of distal memory metal strips, said distal cells comprising a proximal crown located at a proximal end of said distal cells and a distal crown located at a distal end of said distal cells, said strut memory metal strips having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, the distal basket comprises between two and four cords. Optionally, said distal hub is attached to said pull wire such that said distal hub is not slideable along said pull wire. Optionally, said distal basket further comprises a lead wire extending distally from said distal hub. Optionally, said distal hub and said basket are comprised of a nitinol having the same material composition. Optionally, said distal basket and/or said coaxial tube further comprises an x-ray marker. Optionally, said distal hub is generally cylindrical in shape and has an outer diameter and an inner diameter, the inner diameter forming the aperture of the distal hub and further wherein the outer diameter of the distal hub is from about 0.011 inches to about 0.054 inches, and further wherein the inner diameter of the distal hub is from about 0.008 inches to about 0.051 inches. Optionally, the distal tube has an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally the pull wire is generally cylindrical and further wherein the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Optionally, the first height of the distal basket, as measured at the proximal-most crown, is between about 2 millimeters and about 8 millimeters. Optionally, the cords are soft. 
     In some embodiments, the above system is used in a method of removing an object from an interior lumen of an animal, said lumen having an interior wall forming said lumen that includes 
     a) providing the above system;
 
b) positioning the system in said lumen, said basket located in said catheter in a collapsed state;
 
c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction, said coaxial sheath is proximal to said obstruction, said proximal tether memory metal strips are proximal to said obstruction, and said cords are adjacent to said obstruction;
 
d) allowing said distal basket to move to said relaxed state;
 
e) moving said coaxial tube distally relative to said distal hub so that said proximal tether memory metal strips move distally relative to the proximal-most crown and said obstruction is sandwiched between said proximal tether memory metal strips and said proximal crowns of said proximal cells;
 
f) removing said distal basket and said obstruction from said lumen.
 
     Optionally said interior lumen is an intracranial artery and said obstruction is a blood clot. 
     In still further embodiments, the system includes a first wire that is attached to the proximal tube (but not the distal tube) and a second wire that is attached to the distal tube (but not the proximal tube). Preferably, in such embodiments, the system includes two catheters—a guide catheter and a microcatheter. The plurality of memory metal strips attached to the proximal hub include a plurality of proximal tether memory metal strips, which have a proximal end attached to the distal end of the proximal tube. In some embodiments, the present disclosure provides a method of manufacturing a system for removing objects within an interior lumen of an animal comprising: 
     a) providing a single tube comprised of a memory metal, the single tube having an exterior, a hollow interior, a wall separating the exterior from the hollow interior, a proximal portion comprising an aperture leading to the hollow interior, a distal portion comprising an aperture leading to the hollow interior, and a middle portion between the proximal portion and the distal portion;
 
b) cutting the wall of the middle portion with a laser;
 
c) removing the pieces of the middle portion cut by the laser to form a basket system comprising a proximal tube comprising a proximal end, a distal end, and a hollow interior extending through said proximal tube, a distal tube comprising a hollow interior extending through said distal tube, and a middle portion located between said proximal tube and said distal tube and comprising a plurality of proximal memory metal tether strips, each proximal memory metal tether strip having a proximal end attached to the distal end of said proximal tube and a distal end,
 
d) altering the shape of the middle portion;
 
e) allowing the middle portion to expand relative to the distal tube and the proximal tube;
 
f) attaching a first wire to the proximal tube; and
 
g) attaching a second wire to the distal tube.
 
     Optionally, after step e, the basket system further comprises a row of proximal cells, each proximal cell defined by a plurality of memory metal strips and comprising a proximal crown located at a proximal end of the cell and pointing in the proximal direction and a distal crown located at a distal end of the cell and pointing in the distal direction and further wherein each of said proximal crowns of said proximal cells is attached to a distal end of a proximal tether memory metal strip. 
     Optionally, after step e, the basket system further comprises a row of distal cells located distal to said proximal cells and connected to said distal crowns of said proximal cells, each distal cell defined by a plurality of memory metal strips and comprising a proximal crown located at a proximal end of the cell and pointing in the proximal direction and a distal crown located at a distal end of the cell and pointing in the distal direction, and further wherein the number of distal cells is twice the number of proximal cells. Optionally, after step e, the basket system further comprises a row of strut memory metal strips, each strut having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, after step e, the basket system further comprises a row of distal crowns located distal to said proximal crowns and pointing in the distal direction, and further wherein the number of distal crowns in said row is twice the number of proximal crowns attached to said proximal tether memory metal strips. Optionally, the step of attaching said first wire to said proximal tube comprises placing said first wire inside said aperture of said proximal tube and gluing said first wire to said proximal tube. Optionally, the step of attaching said first wire to said proximal tube comprises placing said first wire inside said aperture of said proximal tube and welding said first wire to said proximal tube. Optionally, the step of attaching said first wire to said proximal tube comprises shrink wrapping said first wire to said proximal tube. Optionally, after step e, the basket system comprises between two and four proximal tether memory metal strips. Optionally, the method further comprises not altering the shape of the proximal and distal portions while altering the shape of the middle portion. Optionally, the method further comprises cooling the proximal portion, the middle portion, and the distal portion after step D) and, after cooling, the proximal and distal portions have substantially the same size as the proximal and distal portions had prior to step A). Optionally, the method of allowing said middle portion to expand comprises heating the middle portion. Optionally, the method of altering the shape of the middle portion comprises using a mandrel. Optionally, the mandrel is tapered. Optionally, the proximal portion and the distal portion are not cut by the laser. Optionally, prior to cutting the memory metal tube, the memory metal tube has an outer diameter that is from about 0.011 inches to about 0.054 inches and an inner diameter that is from about 0.008 inches to about 0.051 inches. Optionally, after step e), the proximal tube and distal tube have an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally, the method further includes placing said basket inside a catheter comprised of a biocompatible material. 
     The present disclosure also provides a system for removing objects within an interior lumen of an animal. In some embodiments, the system includes 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end;
 
a distal basket attached to said pull wire, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a proximal tube located at said proximal end of the distal basket, said proximal tube comprising a hollow interior, a plurality of proximal tether memory metal strips, a row of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction, each proximal tether memory metal strip having a proximal end attached to said proximal tube, a distal end attached to a crown of a proximal cell and a length extending from said proximal end to said distal end, a row of distal crowns located distal to said proximal cells pointing in the distal direction, and further wherein the number of distal crowns in said row is twice the number of proximal crowns attached to said proximal tether memory metal strips, and a distal tube located at said distal end of said distal basket,
 
said distal basket having
 
a relaxed state wherein said distal basket has a first height and
 
a collapsed state wherein said distal basket has a second height, said second height less than said first height, and
 
a catheter having an interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said distal body when said distal basket is in said collapsed state.
 
     Optionally, said proximal tether memory metal strips rotate about said pull wire longitudinal axis such that a distal end of a proximal tether memory metal strip is located between about 90 and about 270 degrees relative to said proximal end of the same proximal tether memory metal strip. Optionally, said proximal tether memory metal strips and said proximal cell memory metal strips each have a thickness and further wherein said thickness of said proximal tether memory metal strips is between about 100 to about 175 percent of the thickness of the proximal cell memory metal strips. Optionally, the length of said proximal tether memory metal strips is about 10 mm to about 20 mm in the relaxed (and the length of the remainder of the basket is about 10 to about 20 mm in the relaxed state so that the total basket length is between about 20 to about 40 mm in the relaxed state). Optionally, said distal end of said pull wire is attached to said proximal tube. Some or all of the proximal crowns of said proximal cells may be attached to a proximal tether memory metal strip. Optionally, said distal basket further comprises a row of strut memory metal strips, each strut memory metal strip having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, the distal basket comprises between two and four proximal tether memory metal strips. Optionally, said proximal tether memory metal strips are integral with said proximal tube. Optionally, said distal body further comprises a lead wire extending distally from said distal tube. Optionally, said distal tube, said proximal tube, and said basket are comprised of a nitinol having the same material composition. Optionally, said distal body further comprises an x-ray marker. Optionally, said proximal and said distal tubes are generally cylindrical in shape and each has an outer diameter and an inner diameter, the inner diameter forming the apertures of the proximal and distal tubes and further wherein the outer diameters of the proximal and distal tubes are substantially the same size and further wherein the inner diameters of the proximal and distal tubes are substantially the same size. Optionally, the outer diameters of the proximal and distal tubes are from about 0.011 inches to about 0.054 inches, and further wherein the inner diameters of the proximal and distal tubes are from about 0.008 inches to about 0.051 inches. Optionally, the pull wire is generally cylindrical and further wherein the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Optionally, the first height is between about 2 millimeters and about 8 millimeters. 
     The present disclosure also provides a method of removing an object from an interior lumen of an animal, said lumen having an interior wall forming said lumen, the method comprising the steps of: 
     a) providing the system described above;
 
b) positioning the system in said lumen, said basket located in said catheter in said collapsed state;
 
c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction;
 
d) allowing said distal basket to move to said relaxed state;
 
e) moving said distal basket over said obstruction; and
 
f) removing said distal basket and said obstruction from said lumen.
 
     Optionally, said interior lumen is an intracranial artery and said obstruction is a blood clot. 
     In other embodiments, the system includes: 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end;
 
a proximal basket attached to said pull wire, said proximal basket comprising an interior, an exterior, a proximal end, a distal end, a proximal basket length extending from said proximal basket proximal end to said distal end, a proximal basket height perpendicular to said proximal basket length and said pull wire longitudinal axis, a proximal tube located at said proximal end of the proximal basket, said proximal tube comprising a hollow interior, a plurality of rows of cells, each cell defined by a plurality of memory metal strips, each cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction,
 
a distal basket attached to said pull wire, said distal basket comprising an interior, an exterior, a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a distal tube located at said distal end of the distal basket, said distal tube comprising a distal tube aperture, a plurality of rows of cells, each cell defined by a plurality of memory metal strips, each cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction,
 
a plurality of tether memory metal strips, each tether memory metal strip having a proximal end attached to a distal crown of a cell located at the distal end of said proximal basket and a distal end attached to a proximal crown of a cell located at the proximal end of said distal basket, said proximal basket having
 
a relaxed state wherein said proximal basket has a first height and
 
a collapsed state wherein said proximal basket has a second height, said second height less than said first height and said second width less than said first width,
 
said distal basket having
 
a relaxed state wherein said distal basket has a first height and a first width and
 
a collapsed state wherein said distal basket has a second height and a second width, said second height less than said first height, and
 
a catheter having an interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said distal and said proximal basket when said baskets are in said collapsed state.
 
     Optionally, said tether memory metal strips rotate about said pull wire longitudinal axis such that a distal end of a tether memory metal strip is located between about 90 and about 270 degrees relative to said proximal end of the same proximal tether memory metal strip. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a side, elevation view of a memory metal tube prior to being cut by a laser. 
         FIG. 1B  illustrates a side, elevation view of the memory metal tube of  FIG. 1A  being cut by a laser. 
         FIG. 2A  illustrates a side, elevation view of the memory metal tube of  FIG. 1B  after being cut by a laser; in  FIG. 2A , the tube is shown as though it were flat for purposes of illustrating the cut pattern only. 
         FIG. 2B  illustrates a side, perspective view of the memory metal tube of  FIG. 1B  after being cut by a laser. 
         FIG. 2C  illustrates another side, perspective view of the memory metal tube of  FIG. 1B  after being cut by a laser; in  FIG. 2C , the tube is rotated as compared to  FIG. 2B . 
         FIGS. 3A-3H  illustrate a method of manufacturing a distal body of one embodiment of the present invention using the laser cut memory metal tube of  FIGS. 1 and 2 ; in  FIGS. 3A-3H , the basket portion of the distal body is not shown for simplicity of illustration. 
         FIGS. 4A-4D  illustrate the welding steps of the method of manufacturing shown in  FIG. 3 ; in  FIGS. 4A-4D , the basket portion of the distal body is not shown for simplicity of illustration. 
         FIGS. 5 and 6  illustrate different locations that connector strips may be welded to the proximal memory metal strips. 
         FIG. 7  illustrates a side, elevation view of a catheter and the distal body of  FIG. 6 . 
         FIG. 8  illustrates a side, elevation view of a deployable system of one embodiment of the present invention being used to capture a blood clot; in  FIG. 8 , the basket portion of the distal body is not shown for simplicity of illustration. 
         FIG. 9  illustrates a side, elevation view of a claw of one embodiment of the present invention being closed by a claw actuator tube; in  FIG. 9 , the basket portion of the distal body is not shown for simplicity of illustration. 
         FIG. 10  illustrates a side, elevation view of a deployable system of one embodiment of the present invention being used to capture a blood clot; in  FIG. 10 , the basket portion of the distal body is not shown for simplicity of illustration. 
         FIG. 11  illustrates a first, perspective view of a distal body of an alternate embodiment of the present invention; the distal body is in what is referred to herein as “Orientation  1 ”. 
         FIG. 12A  illustrates a second, perspective view of the distal body of  FIG. 11 ; the distal body is in what is referred to herein as “Orientation  2 ”. 
         FIG. 12B  illustrates a proximal, elevation view of the proximal strips of the distal body of  FIG. 11 . 
         FIG. 13  illustrates a close-up, perspective view of two unattached distal-pointing crowns of the distal body of  FIG. 11 . 
         FIG. 14A  illustrates a native memory metal tube used to manufacture the distal body of  FIG. 11 ; the native tube has been rolled out flat and the lines in the tube indicate where the tube has been cut by a laser. 
         FIG. 14B  illustrates a first, perspective view of the distal body manufactured from the native tube of  FIG. 14A ; the distal body is in Orientation  1 . 
         FIG. 14C  illustrates a second, perspective view of the distal body manufactured from the native tube of  FIG. 14A ; the distal body is in Orientation  2 . 
         FIGS. 15A-G  illustrate stepwise use of the distal body of  FIG. 11  in retrieving a soft clot; the distal body is in Orientation  1 . 
         FIGS. 16A-H  illustrate stepwise use of the distal body of  FIG. 11  in retrieving a hard clot; the distal body is in Orientation  1 . 
         FIGS. 17A-G  illustrate stepwise use of the distal body of  FIG. 11  in retrieving a soft clot; the distal body is in Orientation  2 . 
         FIGS. 18A-G  illustrate stepwise use of the distal body of  FIG. 11  in retrieving a hard clot; the distal body is in Orientation  2 . 
         FIGS. 19A-N  illustrate stepwise use of the distal body of  FIG. 11  in retrieving a deformable, cohesive adherent clot; the distal body is in Orientation  2 . 
         FIG. 20A  illustrates a view of a native memory metal tube used to manufacture a distal body of yet another embodiment of the present invention; the native tube has been rolled out flat, the lines in the tube indicate where the tube has been cut by a laser, and the distal body of  FIGS. 20A-20C  is slightly shorter than the distal body of  FIGS. 11-19  and is meant for use in tortuous blood vessels. 
         FIG. 20B  illustrates a first, perspective view of the distal body manufactured from the native tube of  FIG. 20A ; the distal body is in Orientation  1 . 
         FIG. 20C  illustrates a second, perspective view of the distal body manufactured from the native tube of  FIG. 20A ; the distal body is in Orientation  2 . 
         FIG. 21  shows a perspective view of a clot retrieval system that includes the distal body of  FIGS. 20B-C  being delivered in a blood vessel using a delivery catheter. 
         FIG. 22  shows a perspective view of the distal body of  FIG. 21 , after deployment of the distal body and retraction of the delivery catheter, in a blood vessel. 
         FIG. 23  shows a perspective view of the distal body of  FIG. 21 ; as compared to  FIG. 22 , the distal body has been moved proximally and tension has been exerted on the pull wire. 
         FIG. 24  shows a perspective view of a suction catheter that is being delivered over the pull wire of the system of  FIG. 21 . 
         FIG. 25  shows a perspective view of the distal end of the suction catheter of  FIG. 24  being pushed into a clot; a syringe is sucking the clot to the suction catheter because the user has pulled back on the lever of the syringe. 
         FIG. 26  shows a perspective view of the distal end of the suction catheter of  FIG. 24  being pushed into a clot; in  FIG. 26 , the user has locked the syringe lever at the desired volume. 
         FIG. 27  shows a perspective view of the system of  FIG. 24 ; in  FIG. 27 , the suction catheter has partially sucked the distal body and clot into the suction catheter. 
         FIG. 28  shows a perspective view of the system of  FIG. 24 ; in  FIG. 28 , the suction catheter has completely sucked the distal body and clot into the suction catheter. 
         FIG. 29  shows a perspective view of the system of  FIG. 24 ; the system, and captured clot, is being removed proximally from the vessel. 
         FIG. 30A  illustrates a front, perspective view of a system of another embodiment of the present invention that includes a delivery catheter, a coaxial tube slideable along a pull wire, and proximal strips that extend from the distal end of the coaxial tube and are attached to a distal basket; in  FIG. 30A , the distal basket is in the relaxed state. 
         FIG. 30B  illustrates a front, perspective view of the system of  FIG. 30A ; in  FIG. 30B , the system is in a partially collapsed state due to distal movement of the catheter. 
         FIG. 30C  illustrates a proximal, elevation view of the proximal strips of the system of  FIG. 30A . 
         FIG. 30D  illustrates a proximal, elevation view of an alternate embodiment of  FIGS. 30A and 30B  that includes two proximal strips. 
         FIG. 30E  illustrates a proximal, elevation view of an alternate embodiment of  FIGS. 30A and 30B  that includes four proximal strips. 
         FIG. 31A  illustrates a front, perspective view of the system of  FIG. 30A ; in  FIG. 31A , the system is between the proximal collapsed state and the relaxed state. 
         FIG. 31B  illustrates a front, perspective view of the system of  FIG. 30A ; in  FIG. 31A , the system is in the distal collapsed state. 
         FIG. 32A-F  illustrates a front, perspective view of the system of  FIG. 30A  and stepwise use of the system in retrieving a clot in a human intracranial artery. 
         FIG. 33  illustrates a front, perspective view of an alternate embodiment of the system of  FIGS. 31-32  in which the proximal ends of the proximal strips are attached to the distal end of the coaxial sheath. 
         FIG. 34  illustrates a front, perspective view of an alternate embodiment of the system in which the coaxial sheath is a braided catheter comprised of a plurality of braids and further wherein the distal segment of each braid forms a proximal strip. 
         FIG. 35A-C  illustrate a front, perspective view of an embodiment of the system of  FIGS. 30-34  in which the proximal strips cover the proximal tip of the proximal crowns; in particular,  FIG. 35A  is an exploded view,  FIG. 35B  shows the proximal strip attached to the proximal crown via a loop and an eyelet, and  FIG. 35C  shows how the proximal strips bend backwards to cover the proximal tips when the distal body is in the distal collapsed state. 
         FIGS. 36A-36D  illustrate a side, perspective view of a stepwise sequence of making an embodiment of the basket system of the present invention. 
         FIGS. 37A-37B  illustrate a side, perspective view of stepwise deployment and use of a basket system with proximal tether memory metal strips that are about the same length as the rest of the basket (as measured from the proximal-most crown to the distal tube). 
         FIGS. 38A-38E  illustrate a side, perspective view of stepwise deployment and use of the basket system of  FIGS. 37A-37B  in a blood vessel to retrieve a clot. 
         FIG. 39A  illustrates a side, perspective view of the basket system of  FIGS. 37A and 37B ; as shown, all proximal crowns of the proximal cells are attached to a proximal tether memory metal strip. 
         FIG. 39B  illustrates an alternative embodiment in which one proximal crown of a proximal cell is not attached to a proximal tether memory metal strip. 
         FIG. 40  illustrates a side, perspective view of a basket system with relatively thick proximal tether memory metal strips; in this  FIG. 40 , as shown, the proximal tether memory metal strips are thicker than the memory metal strips forming the proximal-most crown. 
         FIG. 41  illustrates a side, perspective view of a basket system with a proximal basket and a distal basket. 
         FIG. 42  illustrates a side, perspective view of a basket system with a proximal basket and a distal basket in which the proximal tether memory metal strips rotate 180 degrees about both the longitudinal axis of the proximal tether memory metal strips and about the longitudinal axis of the pull wire. 
         FIGS. 43A-43B  illustrate a side, perspective view of a basket system in which the proximal tether memory metal strips rotate 90 degrees about both the longitudinal axis of the proximal tether memory metal strips and about the longitudinal axis of the pull wire. 
         FIG. 43C  illustrates a front, elevation view of the basket system of  FIGS. 43A-43B . 
         FIGS. 43D and 43E  illustrate a front, elevation view and a side, perspective view of a basket system in which the proximal tether memory metal strips rotate 180 degrees about both the longitudinal axis of the proximal tether memory metal strips and about the longitudinal axis of the pull wire. 
         FIGS. 44A-44E  illustrate a side, perspective view of stepwise deployment and use of a basket system with a proximal basket and a distal basket in a blood vessel to retrieve a clot. 
         FIGS. 45A-45D  illustrate a side, perspective view of a stepwise sequence of making an embodiment of the basket system of the present invention. 
         FIGS. 46A-46E  illustrate a side, perspective view of stepwise deployment and use of a basket system with relatively thin and short proximal tether memory metal strips. 
         FIGS. 47A-47H  illustrate a side, perspective view of stepwise deployment and use of the basket system of  FIGS. 46A-46E  in a blood vessel to retrieve a clot. 
         FIGS. 48A-48B  illustrate a side, perspective view of stepwise deployment and use of a basket system with relatively thick and short proximal tether memory metal strips. 
         FIGS. 49A-49C  illustrate a side, perspective view of stepwise deployment and use of a basket system with three relatively thin and short proximal tether memory metal strips; the system is deployed in a blood vessel to retrieve a clot. 
         FIG. 50A  illustrates a side, perspective view of a basket system with relatively thin and short proximal tether memory metal strips; in  FIG. 50A , all proximal crowns of the proximal cells are attached to a proximal tether memory metal strip. 
         FIG. 50B  illustrates a side, perspective view of a basket system with relatively thin and short proximal tether memory metal strips; in  FIG. 50B , one proximal crowns of a proximal cell is not attached to a proximal tether memory metal strip. 
         FIG. 50C  illustrates a front view of a basket system with two proximal tether memory metal strips. 
         FIG. 50D  illustrates a front view of a basket system with three proximal tether memory metal strips. 
         FIG. 50E  illustrates a front view of a basket system with four proximal tether memory metal strips. 
         FIG. 51  illustrates a side, perspective view of a basket system with relatively thin and short proximal tether memory metal strips; in this  FIG. 51 , as shown, the proximal tether memory metal strips are not as thick as the memory metal strips forming the proximal-most crown; further, the thickness of the memory metal strips gradually decreases from the proximal-most crown along the basket length to the distal hub. 
         FIG. 52  illustrates a side, perspective view of a basket system with relatively thin, short proximal tether memory metal strips. 
         FIGS. 53A-53C  illustrate a side, perspective view of stepwise deployment and use of a basket system with relatively long and thin proximal tether memory metal strips; the system is used in a blood vessel to retrieve a clot. 
         FIGS. 54A-54C  illustrate a side, perspective view of a basket system with a proximal basket connected to a distal basket by proximal tether memory metal strips. 
         FIGS. 55A-55B  illustrate a side, perspective view of a basket system in which the proximal tether memory metal strips rotate 90 degrees about both the longitudinal axis of the proximal tether memory metal strips and about the longitudinal axis of the pull wire. 
         FIG. 55C  illustrates a front, elevation view of the basket system of  FIGS. 55A-55B . 
         FIGS. 55D and 55E  illustrate a front, elevation view and a side, perspective view of a basket system in which the proximal tether memory metal strips rotate 180 degrees about both the longitudinal axis of the proximal tether memory metal strips and about the longitudinal axis of the pull wire. 
         FIG. 56  illustrates a side, perspective view of a basket system with relatively thick and short proximal tether memory metal strips. 
         FIG. 57A-E  illustrates a side perspective view of deployment a basket system in which the proximal tether memory metal strips are thicker than the memory metal strips forming the proximal cells of the distal basket. 
         FIGS. 58A-58B  illustrates a side perspective view of a basket system with relatively long cords, instead of proximal tether memory metal strips. 
         FIGS. 59A-59B  illustrates a side perspective view of a basket system with relatively short cords, instead of proximal tether memory metal strips. 
         FIGS. 60A-F  illustrate a perspective view of deployment of the basket system of  FIGS. 59A-59B . 
         FIG. 61  illustrates a side perspective view of a basket system with cords and proximal tether memory metal strips. 
         FIGS. 62A-62C  illustrate a perspective view of deployment of the basket system of  FIG. 61 . 
         FIG. 63  illustrates a right side perspective view of a mandrel used to prepare unattached distal-pointing crowns that curve radially toward the basket interior. 
         FIG. 64  illustrates a right side elevation view of the mandrel of  FIG. 63 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIGS. 1-10 , the present disclosure provides a deployable system, generally designated by the numeral  10 , for removing an obstruction such as a blood clot  12  or other object from a blood vessel  14  or other interior lumen of an animal. In addition to a blood clot  12 , the obstruction may be, for example, extruded coils during aneurysm treatment, intravascular embolic material such as onyx or other obstructions requiring mechanical intravascular removal from small distal vessels. In the drawings, not all reference numbers are included in each drawing for the sake of clarity. 
     Referring further to  FIGS. 1-10 , the deployable system  10  includes a pull wire  16  that has a proximal end (not shown) and a distal end  20 . Optionally, the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Preferably, the pull wire  16  is comprised of a biocompatible metallic material. 
     The system  10  further includes a distal body  22 , which is attached to the pull wire  16 . The distal body  22  has a proximal end  24 , a distal end  26 , an interior  28 , and an exterior  30 . The distal body  22  has a collapsed state, wherein the distal body  22  has a first height and width and is configured to fit into a catheter  50  (see  FIG. 10A ), and a relaxed state wherein the distal body  22  has a different height  32  and width and is configured to expand to about the height and width of a human blood vessel  14  when the distal body  22  is deployed from the catheter  50  (see  FIGS. 10B-G ). The distal body  22  further includes a proximal hub  74  and a distal hub  76  that is located distal relative to the proximal hub  74 . In some embodiments, the distal body  22  includes a plurality of strips  40  comprised of a memory metal (e.g., a memory metal alloy such as nitinol) that form the proximal end  24  of the distal body  22 . Optionally, the proximal memory metal strips  40  each have a distal end  44  and a proximal end  42  that forms an openable and closeable claw  46 . Optionally, the proximal memory metal strips  40  are attached to the proximal hub  74  through connector memory metal strips  48 . In such embodiments, the proximal hub  74  may be slideable along at least a segment of the pull wire  16 , in contrast to the distal hub  76 , which is optionally fixed to the pull wire  16  and not slideable along the pull wire  16 . Moving the proximal hub  74  distally and closer to the distal hub  76  (i.e., shortening the distance  88  between the proximal hub  74  and distal hub  76  by moving the proximal hub  74  distally while keeping the distal hub  76  stationary) exerts tension on the connector memory metal strips  48  and, in turn, the proximal memory metal strips  40 . This tension, in turn, causes the proximal ends  42  of the proximal memory metal strips  40  to move radially toward each other and the pull wire  16 . As the proximal ends  42  of the proximal memory metal strips  40  move radially toward each other and the pull wire  16 , the claw  46  (formed by the proximal memory metal strips  40 ) is brought from the open position to at least a partially closed position, which in turn, separates the obstruction  12  from the wall of the human lumen  14  and captures the obstruction  12 . See  FIG. 3H ,  FIG. 8 ,  FIG. 9F , and  FIGS. 10F and 10G . Conversely, preferably, movement of the proximal hub  74  proximally and away from the distal hub  76  (i.e., increasing the distance  88  between the hubs  74  and  76 ) releases the tension in the proximal memory metal strips  40 , which in turn, causes the proximal ends  42  of the proximal memory metal strips  40  to move away from each other and the pull wire  16 , opening the claw  46 . The claw  46  and proximal hub  74  form several functions. First, as described, closing of the claw  46  captures the obstruction  12 . Second, closing the claw  46  retracts the claw  46  from the wall of the lumen  14  so that the claw  46  does not scrape against (and damage) the lumen wall while capturing the obstruction  12 . Third, closing the claw  46  reduces the height and width of the distal body  22 , which allows the distal body  22  to be re-sheathed in the catheter  50 , which may be desired, for example, if the operator seeks to re-deploy the distal body  22  in another location in the body (which may be the case if the operator originally deploys the distal body  22  in the wrong location in the lumen  14 ). For purposes of the present invention, “closing the claw” embraces both partially closing the claw  46  (where the proximal ends  42  of the proximal memory metal strips  40  do not contact the pull wire  16 ) and fully closing the claw  46  (where the proximal ends  42  contact the pull wire  16 ). 
     The claw  46  may be comprised of any number of proximal memory metal strips  40 . Preferably, however, between 2 and 4 proximal memory metal strips  40  comprise the claw  46  (it being understood that the connector strips  48 , if present, merely serve to tether the claw  46  to the proximal hub  74 ). Preferably, the proximal memory metal strips  40  have a length of between about 10 and about 60 millimeters. The proximal memory metal strips  40  can be thought of as arms of the claw  46 . 
     In some embodiments, the connector strips  48  are integral with the proximal hub  74  (i.e., formed from the same piece of memory metal). In other embodiments, the proximal hub  74  may be welded to the connector strips  48 . Optionally, in the relaxed state, the proximal memory metal strips  42  are distributed substantially evenly about a perimeter of the distal body  22 . 
     Optionally, the distal body  22  includes a lead wire  52  extending distally from the distal body  22 . Optionally, the lead wire  52  extends distally from the distal hub  76 . If present, the lead wire  52  may be used to facilitate movement of the system  10  in the lumen  14 . 
     Optionally, the distal body  22  includes a basket  54  distal to the proximal memory metal strips  40 , the basket  54  comprised of a plurality of memory metal strips  56  distal relative to the proximal memory metal strips  40 . The distal memory metal strips  56  may, for example, form a basket  54  with a plurality of mesh openings  58 . Optionally, the size of the mesh openings  58  in the basket  54  when the distal body  22  is in its relaxed state is less (preferably significantly less) than the diameter of an average-sized ischemic blood clot  12  so that the blood clot  12  does not escape from the distal basket  54  after being captured by the distal body  22 . Optionally, the basket  54  has an open proximal end  60  and a substantially closed distal end  62 , which is formed by distal tube  76 . Optionally, the distal and proximal hubs  74  and  76  and the distal basket  54  are comprised of a nitinol having the same material composition. Optionally, the size of the mesh openings  58  decreases from the proximal end  60  of the basket  54  to the distal end  62 . The distal basket  54  is best seen in  FIG. 2  and can be comprised of a different number of cell patterns. The distal basket  54  is not shown in  FIGS. 3-10  for ease of illustrating the other components in the system  10 . 
     Optionally, the proximal hub  74  and the distal hub  76  are cylindrical tubes comprising substantially circular apertures that span the length of the hubs  74  and  76  and the hubs  74  and  76  have approximately the same inner diameter  72  and the same outer diameter  70 . Preferably, the inner diameter  72  is at least slightly larger than the diameter of the pull wire  16  so that the pull wire  16  can slide through the proximal hub  74 . In some embodiments, the outer diameters  70  of the proximal and distal hubs  74  and  76  may be from about 0.011 inches to about 0.054 inches and the inner diameters  72  of the proximal and distal hubs  74  and  76  may be from about 0.008 inches to about 0.051 inches. 
     Optionally, the distal body  22  further comprises an x-ray marker  64  that is more visible under x-ray as compared to the proximal memory metal strips  40  when the distal body  22  is located in a cranial blood vessel inside the body of a human and the x-ray is taken from outside the human&#39;s body. If the connector strips  48  are welded to the proximal memory metal strips  40 , the x-ray markers  64  may be, for example, located at the welding site. In some cases, the increased thickness at the welding site may in of itself comprise the x-ray marker  64 . Preferably, the x-ray marker  64  is comprised of a radiopaque material. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with radiopaque filler, and the like. Preferably, the proximal memory metal strips  40  are comprised of nitinol and the x-ray marker  64  is comprised of a material having a density greater than the nitinol. 
     A catheter  50  with an open proximal end (not shown) and an open distal end  66  initially envelopes the system  10 . As used herein, the term “catheter” generally refers to any suitable tube through which the system  10  can be deployed. Preferably, the catheter  50  is sterile and comprised of a biocompatible material (i.e., a material that does not irritate the human body during the course of a 45 minute operation that involves using the system  10  to remove a clot  12  from an intracranial blood vessel  14 ). The catheter  50  can be any suitable shape, including but not limited to generally cylindrical. Preferably, the catheter  50  is a microcatheter. For purposes of the present invention, when it is said that the catheter  50  envelopes the system  10 , it will be understood that the catheter  50  envelopes at least one component of the system  10  (preferably, the distal body  22 , the lead wire  52 , and the pull wire  16 ). In some embodiments, the catheter  50  is about 2.5 French in diameter. Optionally, the catheter  50  is delivered to the region of the lumen  14  that has the obstruction  12  as follows: a guide wire is delivered to the obstruction region past the obstruction  12 ; the catheter  50  is delivered over the guide wire; the guide wire is removed; and the system  10  is delivered with its pull wire  16  and lead wire  52  through the catheter  50 . Optionally, the pull wire  16  is used to push the system  10  through the catheter  50  as well as to retrieve the distal body  22  after capturing the obstruction  14  as described below. The system  10  may utilize a plurality of catheters  50 , such as, for example, a wider catheter that travels to the brain and a very flexible, smaller diameter microcatheter that is delivered from the first catheter and travels through the small arteries of the brain. Preferably, the catheter  50  is comprised of a biocompatible, polymeric material (i.e., one or more polymeric materials such as silicone, PVC, latex rubber or braided nylon). 
     Optionally, in the relaxed, opened-claw state, the distal body  22  or optionally just the distal basket  54  has a tapered shape (e.g., substantially conical or bullet in shape) so that the distal body  22  or just the distal basket  54  tapers from the distal body  22  or the distal basket&#39;s 54 proximal end to the distal end. 
     The proximal end of the system  10  is shown at the left end of  FIGS. 1 and 3-10  and the distal end of the system  10  is shown at the right end of  FIGS. 1 and 3-10  because a principal use of the system  10  is to remove a blood clot  12  from a human intracranial artery  14 , in which case the system  10  generally will enter the artery  14  at its proximal end by the surgeon entering the patient&#39;s body near the groin and pushing the catheter  50  towards the brain. The diameter of human arteries  14  generally decrease from their proximal end to their distal end. However, when used in other types of lumens, the distal body  22  may be located proximally relative to the catheter  50  as the term proximally and distally are used in that lumen. 
     The surgeon may deploy the distal body  22  by, for example, moving the catheter  50  proximally so as to unsheathe the distal body  22  or by pushing the distal body  22  out of the catheter  50 . 
     Use of the system  10  will now be described to remove a blood clot  12  from an intracranial artery  14  of a human ischemic stroke patient, however, it will be appreciated that the system  10  may be used to remove other objects from other interior lumens. 
     A catheter  50 , which contains the collapsed distal body  22  is positioned in the lumen  14  distal to the clot  12 . See  FIG. 10A . 
     The distal body  22  is deployed from the catheter  50  and the height and width of the distal body  22  expand to about the height and width of the blood vessel  14 . See  FIG. 10B . 
     The catheter  50  is pulled proximally and a claw-actuator tube  90  is deployed into the blood vessel  14 . See  FIG. 10C . 
     The distal body  22  is moved proximally so that the clot  12  is located in the interior  28  of the distal body  22 . See  FIGS. 10D and 10E . 
     The claw-actuator tube  90  is moved distally, which pushes the proximal hub  74  distally so that the distance  88  between the proximal hub  74  and the distal hub  76  (which is fixed to the pull wire  16  and kept stationary) decreases. Distal movement of the proximal hub  74  exerts tension on the connector and proximal memory metal strips  40  and  48 , which in turn, closes the claw  46 . See  FIG. 10F . (The claw actuator tube  90  should float on the pull wire  16 —i.e., have an aperture extending the tube&#39;s length that has a diameter larger than the diameter of the pull wire  16 —and the aperture of the claw actuator tube  90  should be smaller than the diameter of the proximal hub  74  so that the claw actuator tube  90  pushes the proximal hub  74 ). 
     The system  10  is withdrawn proximally and removed from the body. See  FIG. 10G . 
     To test the efficacy of the system  10 , a distal body  22  with a distal basket  54 , proximal and distal hubs  74  and  76 , and a claw  46  comprised of three proximal memory metal strips  42  was tested in a flow model that included a tube and a moist cotton ball located in the tube. The cotton ball was used to simulate a blood clot. The system  10  was deployed distal to the cotton ball. The claw  46  was closed by moving the proximal hub  74  distally to capture the cotton ball. The system  10  and cotton ball were withdrawn proximally in the tube. 
     In some embodiments, the distal body  22  is prepared by a process that includes one or more of the following steps, as illustrated in  FIGS. 1-4   
     a) providing a single tube  68  comprised of a memory metal such as nitinol, the single tube  68  having an exterior, a substantially hollow interior, a wall separating the exterior from the substantially hollow interior, an open proximal end  74 , an open distal end  76 , a middle portion  78  between the open proximal end  74  and the open distal end  76  (see  FIG. 1A );
 
b) cutting the wall of the middle portion  78  with a laser  80  (see  FIG. 1B );
 
c) removing the pieces of the middle portion  78  cut by the laser  80  to form a proximal tube  74 , a distal tube  76  and a middle portion  78  comprising a plurality of memory metal strips  82  attached to the proximal tube  74 ;
 
d) altering the shape of the middle portion  78  using a mandrel and allowing the middle portion  78  to expand relative to the distal tube  76  and proximal tube  74  to form the distal basket  54 ;
 
e) quenching the middle portion  78  at room temperature;
 
f) removing the mandrel from the middle portion  78  (see  FIGS. 2 and 3A );
 
g) mechanically or chemically electropolishing the middle portion  78  to remove oxides;
 
h) cutting the memory metal strips  82  to form a first segment  84  comprising the proximal tube  74  and a proximal segment of the memory metal strips  82  and a second segment  86  comprising the distal tube  76  and a distal segment of the memory metal strips  82  (see  FIG. 3B ); and
 
i) joining the proximal segments to the distal segments such that the distal segments form the proximal end  24  of the distal body  22 , such that the proximal tube  74  is located inside the interior  28  of the distal body  22 , and such the proximal tube  74  is located distal relative to the distal body proximal end  24  (see  FIGS. 3C-3E ).
 
     In some embodiments, the method further includes placing the pull wire  16  through the proximal tube  74  so that the proximal tube  74  is slideable along at least a segment of the pull wire  16 . 
     In some embodiments, the method further includes attaching the pull wire  16  to the distal tube  76  so that the distal tube  76  is not slideable along the pull wire  16  but instead the distal tube  76  moves with the pull wire  16 . 
     In some embodiments, after step i, the proximal end  24  of the distal body  22  forms a claw  46  comprised of between 2 to 4 proximal memory metal strips  40 , the claw proximal memory metal strips  40  configured to move towards each other and the pull wire  16  by moving the proximal tube  74  distally and toward the distal tube  76  (i.e., decreasing the distance  88  between the tubes  74  and  76 ) and the claw memory metal strips  40  configured to move away from each other and away from the pull wire (i.e., increasing the distance  88  between the tubes  74  and  76 ) by moving the proximal tube  76  proximally and away from the distal tube  76  (as described previously). 
     In some embodiments, the middle portion  78  is expanded by heating the mandrel and the middle portion  78  by, for example, placing the mandrel and the middle portion  78  in a fluidized sand bath at about 500° C. for about 3 to about 7 minutes. As the middle portion  78  is heated, the heating causes the crystalline structure of the memory metal tube  68  to realign. Preferably, the mandrel is tapered (e.g., substantially conical or bullet in shape) so that the distal basket  54  formed from the middle portion  78  tapers from the proximal end  60  to the distal end  62 . Preferably, the proximal and distal ends of the tube  74  and  76  are not shape set by the mandrel and are not cut by the laser  80  so that the proximal and distal ends  74  and  76  do not change in shape and only slightly expand in size under heating and return to the size of the native tube  68  after the heat is removed. Preferably, the laser cuts are programmed via a computer. To ensure that the laser cuts only one surface of the tube wall at the time (and not the surface directly opposite the desired cutting surface), the laser  80  is preferably focused between the inner and outer diameter of the desired cutting surface and a coolant is passed through the memory metal tube  68  so that the laser  80  cools before reaching the surface directly opposite the desired cutting surface. 
     The portions of the wall not cut by the laser  80  create the distal basket  53 , proximal and distal tubes  74  and  76 , and memory metal strips  40 ,  48  and  56 , as described. 
     Preferably, the memory metal selected for the native tube  68  has a heat of transformation below average human body temperature (37° C.) so that the distal body  22  has sufficient spring and flexibility after deployment from the catheter  50  in the human blood vessel  14 . 
     In some embodiments, the native tube  68  (and hence the distal and proximal tubes  74  and  76 ) have an outer diameter of less than about 4 French, e.g., a diameter of about 1 to about 4 French. In some embodiments, the diameter of the pull wire  16  is between about 0.008 inches and about 0.051, as noted above, and in such embodiments, the diameter of the pull wire  16  may be approximately equal to the inner diameter  72  of the native nitinol tube  68 . 
     Without being bound by any particular theory, it is believed that manufacturing the distal body  22  from a single memory metal tube  68  provides ease of manufacturing and safety from mechanical failure and provides tensile strength necessary for the system  10  to remove hard thrombus  12  and other obstructions. 
     The Embodiments of FIGS.  11 - 29   
       FIGS. 11-29  illustrate an alternate embodiment 200 that includes one or more of the following additional features, as described below: twisting proximal strips/tethers  252 , unattached/free distal-pointing crowns  258  that optionally curve inward and have x-ray markers  244 , and enlarged openings/drop zones  262  in the basket  246  immediately distal to the unattached, distal-pointing crowns  258  that allow the obstruction or other object  270  to enter the distal basket interior  222 . 
     More specifically, as shown in  FIGS. 11-29 , the system  200  may include a pull wire  202  having a proximal end  204  and a distal end  206 , as described above, a distal body  216  attached to the pull wire  202 , the distal body  216  comprising an interior  222 , a proximal end  218 , a distal end  220 , a distal body length  226  extending from the proximal end  218  to the distal end  220 , a distal body height  224 , a proximal hub  228  (preferably in the form of a tube and which has a proximal end  230  and a distal end  232 ) forming the proximal end  218  of the distal body  216 , a basket  246  comprised of a plurality of cells/openings  248  formed by a plurality of basket strips  291  that preferably are comprised of a memory metal, optionally a distal hub  236  that forms the distal end  220  of the basket  246  (preferably in the form of a tube that has a proximal end  238  and a distal end  240 ), and a plurality of proximal strips  252  (preferably the proximal strips  252  are comprised of a memory metal), each proximal strip  252  having a proximal end  254  attached to the proximal hub/tube  228 , and a distal end  256  attached to a cell  248  (more specifically a proximal-pointing crown of a cell  248  located at the proximal end of the basket  246 ), the basket comprising a basket interior  292 , the distal body  216  having a relaxed state wherein the distal body  216  has a first height and width, a collapsed state wherein the distal body  216  has a second height and width, the second height less than the first height, the second width less than the first width; and a delivery catheter  208  for delivering the distal body  216 , as described above, having an interior  210 , a proximal end  212  leading to the interior  210  and a distal end  214  leading to the interior  210 , the delivery catheter  208  comprised of a biocompatible (preferably polymeric) material and configured to envelope the distal body  216  when the distal body  216  is in the collapsed state. Optionally, the basket interior  292  is substantially hollow—i.e., unlike U.S. Patent Publication No. 2013/0345739, the basket interior  292  does not contain an inner elongate body. Optionally, instead of a distal hub  236 , the basket  246  includes an open distal end. Optionally, at least two cells  250  of the basket  246  comprise a proximal crown  260  pointing generally in the proximal direction and a distal crown  258  pointing generally in the distal direction, and the distal crowns  258  of the at least two cells  250  are not attached to another cell  248  of the basket  246 . In other words, the distal crowns  258  of at least two cells  250  are free floating and are not attached to any strip except for the strips forming part of the at least two cells  250 ; such distal crowns  258  are referred to below as unattached, distal-pointing crowns  258 . Preferably, the distal tips of the unattached, distal-pointing crowns  258  terminate at an x-ray marker  244 . (Cells labeled with the numerals  250 ,  250 A,  250 B,  250 C, and  250 D refer to the at least two cells that include a proximal crown  260  pointing generally in the proximal direction and an unattached, distal-pointing crown  258 , cells labeled with the numerals  262 ,  262 A,  262 B,  262 C, and  262 D refer to the enlarged cells/drop zones adjacent to (preferably immediately distal to) an unattached, distal-pointing crown  258 , and cells designated with numeral  248  refer to generally the cells of the basket  246 ). (When it is said that the enlarged cells/drop zones  262  are preferably immediately distal to an unattached, distal-pointing crown  258 , it will be understood that at least a portion of an enlarged cell/drop zone  262  is immediately distal to an unattached, distal-pointing crown  258 , and that a portion of the enlarged cell/drop zone  262  may be proximal to an unattached, distal-pointing crown  258 , as shown in  FIGS. 11-12  due to the shape of the enlarged cells/drop zones  262 ). It will be understood that part number  250  refers generally to one or more of the at least two cells, whereas part numbers  250 A,  250 B,  250 C, and  250 D refer to a specific one of the at least two cells. Similarly, it will be understood that part number  262  refers generally to one or more of the enlarged cells/drop zones, whereas part numbers  262 A,  262 B,  262 C, and  262 D refer to a specific one of the enlarged cells/drop zones. Similarly, it will be understood that part number  258  refers generally to one or more of the unattached, distal-pointing crowns, whereas part numbers  258 A,  258 B,  258 C, and  258 D refer to a specific one of the unattached, distal-pointing crowns. 
     Optionally, at least two of the unattached, distal-pointing crowns  258  are located approximately 180 degrees (e.g., about 150 to about 180 degrees) relative to each other and approximately the same distance from the proximal hub/tube  228 , as best seen in  FIG. 12A . Optionally, the basket  246  comprises a first pair of unattached, distal-pointing crowns  258 A and  258 B, each of the first pair of unattached, distal-pointing crowns  258 A and  258 B is located approximately the same distance from the proximal hub/tube  228  and approximately 180 degrees relative to each other, and the basket  246  further comprises a second pair of unattached, distal-pointing crowns  258 C and  258 D located distally relative to, and approximately 90 degrees (e.g., between about 60 and about 90 degrees) relative to, the first pair of unattached, distal-pointing crowns  258 A and  258 B. Optionally, the second pair of unattached, distal-pointing crowns  258 C and  258 D form cells  250 C and  250 D that are adjacent to, but offset from, the cells  250 A and  250 B formed by the first pair of unattached, distal-pointing crowns  258 A and  258 B. (In other words, optionally, the center of cell  250 A is about 90 degrees relative to the centers of cells  250 C and  250 D and optionally the center of cell  250 B is also about 90 degrees relative to the centers of cells  250 C and  250 D). Optionally, at least one of (and preferably all) the unattached, distal-pointing crowns  258 A,  258 B,  258 C or  258 D comprise an x-ray marker  244  that is more visible under x-ray as compared to the basket strips  291  when the distal body  216  is located in a cranial blood vessel  266  inside the body of a human and the x-ray is taken from outside the human&#39;s body. Preferably, the x-ray marker  244  is a radiopaque material. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with radiopaque filler, and the like. Preferably, the basket strips  291  are comprised of nitinol and the x-ray marker  244  is comprised of a material having a density greater than the nitinol. In some embodiments, the x-ray markers  244  comprise a heavy metal welded to the unattached, distal-pointing crowns  258 . Optionally, the unattached, distal-pointing crowns  258  curve subtly towards the interior  222  of the distal basket  246 , which decreases the likelihood that the unattached, distal-pointing crowns  258  will rub against and damage the vessel wall  268 . Optionally, the basket  246  comprises at least two cells proximal to the at least two cells  250  that include the unattached, distal-pointing crowns  258 . Optionally, the unattached, distal-pointing distal crowns  258  are located about at least 5 mm (e.g., about 5 to about 30 mm) from the proximal hub/tube  228 . Optionally, the unattached, distal-pointing crowns  258  are located at least about 5 mm from the distal hub/tube  236 . Optionally, the unattached, distal-pointing crowns  258  of the at least two cells  250  also each form part (namely a portion of the proximal boundary) of an enlarged cell  262  (which is the entry point of hard thrombus  270 B into the basket interior  222 ) and further wherein the surface area of the enlarged cells  262  in the relaxed state is greater than the surface area of the other cells of the basket  246  in the relaxed state. Optionally, the unattached, distal-pointing crowns  258  serve several functions: 1) they form flex points of the basket  246 , which makes it easier for the system  200  to navigate the curves of the blood vessels  266  of the brains; 2) through the use of x-ray markers  244  on the unattached, distal-pointing crowns  258 , they allow the operator to locate the enlarged cells  262  of the basket  246  that form the point at which hard thrombuses  270 B enter the basket  246 ; and 3) they allow the operator to ratchet or force the object  270  into the basket  246  by moving the unattached, distal-pointing crowns  258  proximally and distally relative to the object  270 . (As explained below, the numeral  270  refers to clots/thrombuses and other objects generally, and  270 A refers to a soft clot,  270 B refers to a hard clot and  270 C refers to a deformable, cohesive, adherent clot). Optionally, the proximal end  254  of a proximal strip  252  is located about 65-180 degrees (preferably approximately 180 degrees) relative to the distal end  256  of the same proximal strip  252 , as best seen in  FIG. 12B . In other words, preferably the proximal end  254  of a first proximal strip  252  is attached to the 12 o&#39;clock position on the proximal tube  228  and the distal end  256  of the first proximal strip  252  (which terminates at a proximal cell  248  of the basket  246 ) is located at the 6 o&#39;clock position (i.e., 180 degrees from the start position), and the proximal end  254  of a second proximal strip  252  is attached to the 6 o&#39;clock position on the proximal tube  228  and the distal end  254  (which terminates at a cell  248  of the basket  246 ) of the second proximal strip  252  is located at the 12 o&#39;clock position (i.e., 180 degrees from the start position). This twisting feature serves two functions: 1) it allows the proximal strips  252  to surround the object  270 ; and 2) it allows the manufacturer to insert a mandrel into the basket  246  during the shape-setting procedure. Optionally, the pull wire  202  is attached to the proximal tube  228  (e.g., by gluing, welding or the like). Preferably, the pull wire  202  does not extend through the distal basket interior  222 . Optionally, the proximal strips  252  are integral with the distal end  232  of the proximal tube  228  and the entire distal body  216  is created from a single tube  264  of a memory metal. Optionally, the proximal crowns  260  of the at least two cells  250  that include the unattached, distal pointing-crowns  258  are each attached to another cell  248  of the basket  246 . In other words, preferably the basket  246  does not have any free-floating proximal-pointing crowns, as free-floating proximal-pointing crowns could damage the vessel  266  when the distal body  216  is pulled proximally. Optionally, the system  200  further comprises a lead wire  286  extending distally from the distal tube  236 , the lead wire  286  having a length of from about 3 mm to about 10 mm. Optionally, the distal hub/tube  236 , the proximal hub/tube  228 , and the basket  246  are comprised of a nitinol having the same material composition. In other words, as with the prior embodiment of  FIGS. 1-10 , optionally the entire distal body  216  is manufactured from a single tube of nitinol  264 . Optionally, the proximal and distal hubs/tubes  228  and  236  comprise an x-ray marker  244  that is more visible under x-ray as compared to the basket strips  291  when the distal body  216  is located in a cranial blood vessel  266  inside the body of a human and the x-ray is taken from outside the human&#39;s body. Preferably, the x-ray marker  244  is a radiopaque material. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with radiopaque filler, and the like. Preferably, the basket strips  291  are comprised of nitinol and the x-ray marker  244  is comprised of a material having a density greater than the nitinol. In some embodiments, the proximal and distal hubs/tube interiors  234  and  242  may comprise tantalum welded or otherwise attached to the interior  234  and  242  of the proximal and distal hubs/tubes  228  and  236 . Optionally, the proximal and the distal tubes  228  and  236  are generally cylindrical in shape and each has an outer diameter and an inner diameter, the inner diameter forming apertures of the proximal and distal tubes  228  and  236  and further wherein the outer diameters of the proximal and distal tubes  228  and  236  are substantially the same size and further wherein the inner diameters of the proximal and distal tubes  228  and  236  are substantially the same size. Optionally, the outer diameters of the proximal and distal tubes  228  and  236  are from about 0.011 inches to about 0.054 inches, and further wherein the inner diameters of the proximal and distal tubes  228  and  236  are from about 0.008 inches to about 0.051 inches. Optionally, the pull wire  202  is generally cylindrical and further wherein the diameter of the pull wire  202  is between about 0.008 inches and about 0.051 inches. Optionally, the distal body  216  has a length of between about 10 and about 60 millimeters. Optionally, the first height  224  and first width  226  of the distal body  216  are between about 2 millimeters and about 6 millimeters. 
     The present disclosure also provides a method of removing a clot or other object  270  from an interior lumen  266  of an animal, the method comprising the steps of: 
     a) providing the system  200  of  FIGS. 11-29 , wherein at least two cells  250  of the basket  246  comprise a proximal crown  260  pointing generally in the proximal direction and a distal crown  258  pointing generally in the distal direction, and the distal crowns  258  of the at least two cells  250  are not attached to another cell  248  of the basket  246  (i.e., free-floating), and further wherein at least one of the unattached, distal-pointing crowns  258  comprises an x-ray marker  244 ; 
     b) positioning the system  200  in the lumen  266 ; 
     c) deploying the distal body  216  from the distal end  214  of the delivery catheter  208 ; 
     d) allowing the height and width  224  and  226  of the distal body  216  to increase; 
     e) irradiating the x-ray marker  244  with x-ray radiation and 
     f) moving the object  270  into the distal basket interior  222 . 
     Optionally, the object  270  enters the distal basket interior  222  adjacent to (preferably adjacent and immediately distal to) at least one of the unattached, distal-pointing crowns  258 —i.e., in the enlarged cells/drop zones  262 . In some embodiments, the distal body  216  is deployed so that at least one (e.g., preferably the two proximal  258 A and  258 B) of the unattached, distal-pointing crowns  258  is distal to the object  270 . As explained below, the x-ray markers  244  of the unattached, distal-pointing crowns  258  are used to locate the distal body  216  relative to the clot or other object  270 . It will be appreciated that clots  270  can generally be located in blood vessels  266  by injecting a contrast dye, for example, into the blood vessel  266  proximal and distal to the believed area of obstruction and viewing on an x-ray where the fluid stops moving in the blood vessel  266 . It will also be appreciated that if the object  270  is not a blood clot but is a radio-opaque object, the object  270  may be viewed on an x-ray. 
       FIGS. 11 and 14B  illustrate a first, perspective view of one embodiment of a distal body  216  with twisting proximal strips  252 , unattached distal-pointing crowns  258  that subtly curve inward and have x-ray markers  244 , and enlarged openings/drop zones  262  in the basket  246  that allow the obstruction or other object  270  to enter. In  FIGS. 11 and 14B , the distal body  216  is in Orientation  1 . (To prepare a basket  246  with unattached distal-pointing crowns  258  that curve inward toward the basket interior  292 , a mandrel  900  such as that illustrated in  FIGS. 63 and 64  may be used. The mandrel  900  includes a generally cylindrical body  901  with tapered proximal and distal ends  902  and  903  that slope like the ends of a pencil. The cylindrical body  901  includes two grooves  904  that extend around the circumference of the cylindrical body  901 . The grooves  904  include tapered portions  905  that slope towards the distal end  903 , which are designed to shape the unattached distal-pointing crowns  258 . The grooves  904  are generally in the shape of a truncated cone, as shown in  FIGS. 63-64 ). The two proximal, unattached distal-pointing crowns  258 A and  258 B are located approximately the same distance from the proximal hub/tube  228  and are oriented approximately 180 degrees relative to each other. The two distal, unattached distal-pointing crowns  258 C and  258 D are located approximately the same distance from the proximal hub/tube  228  as each other (and distal to the two proximal, unattached distal-pointing crowns  258 A and  258 B) and are oriented approximately 180 degrees relative to each other and approximately 90 degrees to the proximal, unattached distal-pointing crowns  258 A and  258 B. The two proximal enlarged openings/drop zones  262 A and  262 B distal to the proximal, unattached distal pointing crowns  258 A and  258 B are located approximately the same distance from the proximal hub/tube  228  and the centers of the two proximal enlarged openings/drop zones  262 A and  262 B are oriented approximately 180 degrees relative to each other. (As noted above, preferably, the proximal, unattached distal-pointing crowns  258 A and  258 B form part of the proximal boundary of the proximal, enlarged cells/drop zones  262 A and  262 B, and the distal, unattached distal-pointing crowns  258 C and  258 C form part of the proximal boundary of the distal, enlarged cells/drop zones  262 C and  262 D). The two distal, enlarged openings/drop zones  262 C and  262 D distal to the distal, unattached distal pointing crowns  258 C and  258 D are located approximately the same distance from the proximal hub/tube  228  and the centers of the distal, enlarged openings/drop zones  262 C and  262 D are oriented approximately 180 degrees relative to each other and approximately 90 degrees relative to the proximal enlarged openings/drop zones  262 A and  262 B.  FIGS. 12A and 14C  illustrate a second view of the distal body  216  of  FIG. 11  (Orientation  2 ).  FIG. 13  is a close-up view of two unattached, distal-pointing crowns  262 . The lines in  FIG. 14  show how a nitinol tube  264  is cut with a laser to create the distal body  216  shown in  FIG. 14B  and  FIG. 14C . It will be appreciated that  FIG. 14B  is a simplified view of the distal body  216  and orientation shown in  FIG. 11  and  FIG. 14C  is a simplified view of the distal body  216  and orientation shown in  FIG. 12A . 
     As described below,  FIGS. 15-19  describe how the distal body  216  is used to retrieve, soft clots  270 A, hard clots  270 B, and deformable, cohesive adhesive clots  270 C in a human intracranial artery  266 . (In  FIGS. 15-19 , the center of the artery  266  is denominated by the dashed line). As explained below, the distal body  216  has four rows of x-ray markers namely, 1) a first row of one x-ray marker, which is located inside the proximal tube denominated by the numeral  228 ,  244 ; 2) a second row of two x-ray markers, which are located at the two proximal, unattached distal-pointing crowns (the two markers are oriented 180 degrees relative to each other) denominated by the numerals  258 A,  244  and  258 B,  244 ; 3) a third row of two x-ray markers, which are located at the two distal, unattached distal-pointing crowns (these two markers are oriented 180 degrees relative to each other and 90 degrees relative to the two proximal, unattached distal-pointing crowns) denominated by the numerals  258 C,  244  and  258 D,  244 ; and 4) a fourth row of one x-ray marker, which is located inside the distal tube denominated by the numeral  236 ,  244 . (It will be appreciated that the first number in the sequence describes the position of the x-ray marker and the second number,  244 , represents the fact that the item is an x-ray marker). As explained below, upon deploying the distal body  216  so that the two proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244  are immediately distal to the clot  270 , the surgeon interventionalist (i.e., operator of the distal body  216 ) detects the four rows of x-ray markers using x-ray radiation from a first vantage point and from a second vantage point that is offset from the first vantage point (e.g. 90 degrees). Next, the surgeon moves the distal body  216  proximally relative to the clot  270  and takes additional x-rays from the first and second vantage points. As explained in greater detail below, the surgeon uses the x-ray markers of the proximal and distal, unattached distal-pointing crowns, namely  258 A,  244 ;  258 B,  244 ;  258 C,  244 ; and  258 D,  244  (more specifically, the convergence or lack thereof of the proximal and distal, unattached distal-pointing crowns  258 A,  244 ;  258 B,  244 ;  258 C,  244 ; and  258 D,  244  as shown on the x-ray) to determine whether the clot  270  is located inside the distal body interior  222  or whether the clot  270  is collapsing the distal body  216 . 
     More specifically,  FIGS. 15A-G  illustrate stepwise use of the distal body  216  in retrieving a soft clot  270 A in a human intracranial artery  266 . (The distal body  216  in  FIGS. 15A-15G  is in Orientation  1 ). First, as always, the surgeon determines the location of the clot  270 A in the vessel  266  using, for example, a contrast dye injected proximal and distal to the clot  270 A. Next, the delivery catheter  208 , which is enveloping the distal body  216 , is positioned in the blood vessel  266  so that the two proximal, unattached distal-pointing crowns  258 A and  258 B are immediately distal to the clot  270 A. See  FIG. 15B . The distal body  216  is then deployed from the delivery catheter  208  by moving the catheter  208  proximally. The soft clot  270 A, which is unable to collapse the distal body  216 , then enters the distal body interior  222 . See  FIG. 15C . However, at this time, the surgeon is unaware that the clot  270 A has entered into the distal body interior  222 . Thus, without moving the distal body  216 , the surgeon irradiates the four rows of x-ray markers at a first vantage point (i.e., from the front of the distal body  216  in the orientation shown in  FIGS. 15A-G ; i.e., into the page). As shown in  FIG. 15D , the first vantage point shows four rows of x-ray markers. The first row is a single point, which represents the x-ray marker located in the proximal tube  228 ,  244 ; the proximal tube x-ray marker  228 ,  244  always appears as a single point. The second row is a single point, which represents the x-ray marker located at the front, proximal, unattached distal-pointing crown  258 B,  244 ; the reason that this second row of markers is a single point is that the rear x-ray marker of the second row  258 A,  244  is hidden from view because it is directly behind the front x-ray marker of the second row  258 B,  244 . The third row has two points, which represents the two x-ray markers located at the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244 ; the reason that this third row of markers has two points is that neither marker in the third row  258 C,  244  and  258 D,  244  is hidden from view on the x-ray at this angle—rather, one marker  258 C,  244  is located above the other marker  258 D,  244 —and as shown in  FIG. 15C , the distal body  216  is not collapsed at the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244 . The fourth row is a single point, which represents the x-ray marker located in the distal tube  236 ,  244 ; the distal tube x-ray marker  236 ,  244  always appears as a single point. Without moving the distal body  216 , the surgeon then irradiates the four rows of x-ray markers from a second vantage point 90 degrees offset from the first vantage point (i.e., from the bottom of the distal body  216  in the orientation shown in  FIG. 15A ). As shown, the first row is, as always, a single point, which represents the x-ray marker located in the proximal tube  228 ,  244 . The second row has two points, which represents the two x-ray markers located at the proximal, unattached distal-pointing crown  258 A,  244  and  258 B,  244 ; the reason that this second row of markers shows up as two points is that neither marker  258 A,  244  and  258 B,  244  in the second row is hidden from view on the x-ray at this offset angle—rather, one marker  258 B,  244  is located above the other marker  258 A,  244 —and the distal body  216  is not collapsed at the proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244 . The third row is a single point, which represents the x-ray marker located at the bottom, distal, unattached distal-pointing crown  258 D,  244 ; the reason that this third row of markers is a single point is that the top x-ray marker of the third row  258 C,  244  is directly behind the bottom x-ray marker of the third row  258 D,  244 , and thus, hidden from view. The fourth row is, as always, a single point, which represents the x-ray marker located in the distal tube  236 ,  244 . The surgeon, thus, concludes that neither the x-ray markers at the second row  258 A,  244  and  258 B,  244  nor the x-ray markers at the third row  258 C,  244  and  258 D,  244  (i.e., the x-ray markers at both the proximal and distal unattached distal pointing-crowns) have converged. As shown in  FIG. 15E , the surgeon then moves the distal body  216  proximally relative to the soft clot  270 A so that the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244  are immediately distal to the clot  270 A and then the surgeon irradiates the four rows of x-ray markers again from the first vantage point and the second vantage point. As shown in  FIG. 15F , the results are the same as  FIG. 15D . With the results from  FIGS. 15D and 15F , the surgeon concludes that neither x-ray markers at the second row  258 A,  244  and  258 B,  244  nor the x-ray markers at the third row  258 C,  244  and  258 D,  244  (i.e., the x-ray markers at both the proximal and distal unattached distal pointing-crowns) converged at either the original position of the distal body  216  ( FIGS. 15C and 15D ) or the position after moving the distal body  216  proximally ( FIGS. 15E and 15F ), and, thus, the distal body  216  was expanded in the vessel  266  in both positions. Thus, the surgeon concludes that the clot is a soft clot  270 A that has entered into the distal body interior  222  and the surgeon removes the distal body  216  and the soft clot  270 A, captured by the distal body  216 , by moving the distal body  216  proximally out of the vessel  266 , as shown in  FIG. 15G . 
       FIGS. 16A-H  illustrate stepwise use of the distal body  216  in retrieving a hard clot  270 B in a human intracranial artery  266 . (In  FIGS. 16A-H , the distal body  216  is in Orientation  1 ). First, as always, the surgeon determines the location of the clot  270 B in the vessel  266  using, for example, a contrast dye injected proximal and distal to the clot  270 B. Next, the delivery catheter  208 , which is enveloping the distal body  216 , is positioned in the blood vessel  266  so that the two proximal, unattached distal-pointing crowns  258 A and  258 B are immediately distal to the clot  270 B. See  FIG. 16B . The distal body  216  is then deployed from the delivery catheter  208  by moving the catheter  208  proximally. The hard clot  270 B, which is located above the distal body  216 , collapses the distal body  216 , as shown in  FIG. 16C . However, at this time, the surgeon is unaware that the clot  270 B has collapsed the distal body  216 . Thus, without moving the distal body  216 , the surgeon irradiates the x-ray markers at a first vantage point (i.e., from the front of the distal body  216 ; i.e., into the page). As shown in  FIG. 16D , the first vantage point shows four rows of x-ray markers. The first row is, as always, a single point, representing the x-ray marker located in the proximal tube—i.e.,  228 ,  244 . The second row is a single point, which represents the x-ray marker located at the front, proximal, unattached distal-pointing crown  258 B,  244 ; the reason that this second row of markers is a single point is that the rear x-ray marker of the second row  258 A,  244  is hidden from view because it is directly behind the front x-ray marker of the second row  258 B,  244 . The third row has two points, which represents the two x-ray markers located at the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244 ; the reason that this third row of markers has two points is that neither marker in the third row is hidden from view on the x-ray at this angle—rather, one marker  258 C,  244  is located above the other marker  258 D,  244 —and as shown in  FIG. 16C , the distal body  216  is not collapsed at the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244 . The fourth row is, as always, a single point, representing the x-ray marker located in the distal tube  236 ,  244 . Without moving the distal body  216 , the surgeon then irradiates the markers from a second vantage point 90 degrees offset from the first vantage point (i.e., from the bottom of the distal body  216 ). As shown, the first row is, as always, a single point, which represents the x-ray marker located in the proximal tube  228 ,  244 . The second row has two points, which represents the two x-ray markers located at the proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244 ; the reason that this second row of markers shows up as two points is that neither marker in the second row is hidden from view on the x-ray at this offset angle—rather, one marker  258 B,  244  is located above the other marker  258 A,  244 —and although the distal body  216  is collapsed at the proximal, unattached distal-pointing crowns as shown in  FIG. 16C , the second row of x-ray markers have not converged because the clot  270 B is on top of the second row of x-ray markers. The third row is a single point, which represents the x-ray marker located at the bottom, distal, unattached distal-pointing crown  258 D,  244 ; the reason that this third row of markers is a single point is that the top x-ray marker of the third row  258 C,  244  is directly behind the bottom x-ray marker of the third row  258 D,  244 , and thus, hidden from view. The fourth row is, as always, a single point, which represents the x-ray marker located in the distal tube  236 ,  244 . The surgeon, thus, concludes that neither the second row  258 A,  244  and  258 B,  244  nor the third row  258 C,  244  and  258 D,  244  of x-ray markers (i.e., the x-ray markers at both the proximal and distal unattached distal pointing-crowns) has converged. As shown in  FIG. 16E , the surgeon then moves the distal body  216  proximally so that the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244  are immediately distal to the clot  270 B and the surgeon then irradiates the x-markers again from the first vantage point. As shown in  FIG. 16F , the first row is, as always, a single point, representing the x-ray marker located in the proximal tube  228 ,  244 . The second row is a single point, which represents the x-ray marker located at the front, proximal, unattached distal-pointing crown  258 B,  244 ; the reason that this second row of markers is a single point is that the rear x-ray marker of the second row  258 A,  244  is hidden from view because it is directly behind the front x-ray marker of the second row  258 B,  244 . The third row has only one point because the clot  270 B, which is on top of the third row of x-ray markers  258 C,  244  and  258 D,  244  (i.e., the markers at the distal, unattached distal-pointing crowns), has pushed the third row of x-ray markers  258 C,  244  and  258 D,  244  together. The fourth row is, as always, a single point, representing the x-ray marker located in the distal tube  236 ,  244 . Without moving the distal body  216 , the surgeon then irradiates the markers from a second vantage point 90 degrees offset from the first vantage point (i.e., from the bottom of the distal body). As shown, the first row is, as always, a single point, which represents the x-ray marker located in the proximal tube  228 ,  244 . The second row has two points, which represents the two x-ray markers located at the proximal, unattached distal-pointing crown  258 A,  244  and  258 B,  244 ; the reason that this second row of markers shows up as two points is that neither marker in the second row is hidden from view on the x-ray at this offset angle and the distal body  216  is not collapsed at the proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244 . The third row is a single point, which represents the x-ray marker located at the bottom, distal, unattached distal-pointing crown  258 D,  244 ; the reason that this third row of markers is a single point is that the bottom x-ray marker of the third row  258 D,  244  is directly in front of the top x-ray marker of the third row  258 C,  244 , and thus, the top x-ray marker of the third row  258 C,  244  is hidden from view. The fourth row is, as always, a single point, which represents the x-ray marker located in the distal tube  236 ,  244 . Knowing that the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244  have converged as shown in  FIG. 16F , the surgeon moves the distal body  216  proximally and the hard clot  270 B falls into the distal body interior  222  in the enlarged cell/drop zone  262 C immediately distal to the top, distal, unattached distal-pointing crown  258 C. See  FIG. 16G . To confirm that the hard clot  270 B has entered the distal body interior  222 , the surgeon takes x-rays from the first and second vantage points. The results are shown in  FIG. 16H . As compared to  16 F, the front x-ray view of  FIG. 16H  shows that the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244  are not converged, and, thus, the surgeon concludes that the hard clot  270 B has entered the distal body interior  222 . The surgeon then removes the distal body  216  and the hard clot  270 B, captured by the distal body  216 , by moving the distal body  216  proximally out of the vessel  266 . 
       FIGS. 17A-G  illustrate stepwise use of the distal body  216  in retrieving a soft clot  270 A in a human intracranial artery  266 . (In  FIGS. 17A-G , the distal body  216  is in Orientation  2 ). First, as always, the surgeon determines the location of the clot  270 A in the vessel  266  using, for example, a contrast dye injected proximal and distal to the clot  270 A. Next, the delivery catheter  208 , which is enveloping the distal body  216 , is positioned in the blood vessel  266  so that the two proximal, unattached distal-pointing crowns  258 A and  258 B are immediately distal to the clot  270 A. See  FIG. 17B . The distal body  216  is then deployed from the catheter  208  by moving the catheter  208  proximally. The soft clot  270 A, which is unable to collapse the distal body  216 , then enters the distal body interior  222 . See  FIG. 17C . However, at this time, the surgeon is unaware that the clot  270 A has entered into the distal body interior  222 . Thus, without moving the distal body  216 , the surgeon irradiates the x-ray markers at a first vantage point (i.e., from the front of the distal body; into the page). As shown in  FIG. 17D , the first vantage point shows four rows of x-ray markers. The first row is, as always, a single point, representing the x-ray marker located in the proximal tube  228 ,  244 . The second row has two points, which represents the two x-ray markers located at the proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244 ; the reason that this second row of markers has two points is that neither marker in the second row is hidden from view on the x-ray at this angle—rather, one marker  258 A,  244  is located above the other marker  258 B,  244 —and as shown in  FIG. 17C , the distal body  216  is not collapsed at the proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244 . The third row has a single point, which represents the x-ray marker located at the front (in Orientation  2 ), distal, unattached distal-pointing crown  258 C,  244 ; the reason that this third row of markers is a single point is that the rear (in Orientation  2 ) x-ray marker  258 D,  244  of the third row is hidden from view because it is directly behind the front x-ray marker  258 C,  244  of the third row. The fourth row is, as always, a single point, representing the x-ray marker located in the distal tube  236 ,  244 . Without moving the distal body, the surgeon then irradiates the markers from a second vantage point 90 degrees offset from the first vantage point (i.e., from the bottom of the distal body, as shown in this view). As shown, the first row is, as always, a single point, which represents the x-ray marker located in the proximal tube  228 ,  244 . The second row is a single point, which represents the x-ray marker located at the bottom (in Orientation  2 ), proximal, unattached distal-pointing crown  258 B,  244 ; the reason that this second row of markers is a single point is that the top (in Orientation  2 ) x-ray marker of the second row  258 A,  244  is directly behind the bottom x-ray marker of the second row  258 B,  244 , and thus, hidden from view. The third row has two points, which represents the two x-ray markers located at the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244 ; the reason that this third row of markers shows up as two points is that neither marker in the third row is hidden from view on the x-ray at this offset angle and the distal body  216  is not collapsed at the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244 . The fourth row is, as always, a single point, which represents the x-ray marker located in the distal tube  236 ,  244 . The surgeon, thus, concludes that neither the second row  258 A,  244  and  258 B,  244  nor the third row of x-ray markers  258 C,  244  and  258 D,  244  (i.e., the x-ray markers at both the proximal and distal unattached distal pointing-crowns) has converged. As shown in  FIG. 17E , the surgeon then moves the distal body  216  proximally relative to the clot  270 A so that the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244  are immediately distal to the clot  270 A and then the surgeon irradiates the x-markers again from the first vantage point and the second vantage point. As shown in  FIG. 17F , the results are the same as  FIG. 17D . With the results from  FIGS. 17D and 17F , the surgeon concludes that neither the second row  258 A,  244  and  258 B,  244  nor the third row of x-ray markers  258 C,  244  and  258 D,  244  (i.e., the x-ray markers at both the proximal and distal unattached distal pointing-crowns) were converged at either the original position of the distal body  216  ( FIGS. 17C and 17D ) or the position after moving the distal body  216  proximally ( FIGS. 17E and 17F ), and, thus, the distal body  216  was expanded in the vessel  266  in both positions. Thus, the surgeon concludes that the clot  270 A is a soft clot  270 A that has entered into the distal body interior  222  and the surgeon removes the distal body  216  and the soft clot  270 A, captured by the distal body  216 , by moving the distal body  216  proximally out of the vessel  266 , as shown in  FIG. 17G . 
       FIGS. 18A-G  illustrate stepwise use of the distal body  216  in retrieving a hard clot  270 B in a human intracranial artery  266 . (In  FIGS. 18A-G , the distal body  216  is in Orientation  2 ). (As described below, the primary differences between  FIGS. 18A-G  and  FIGS. 16A-G  is that the clot  270 B enters the distal body interior  222  in an enlarged cell/drop zone  262 A immediately distal to one of the proximal, unattached distal-pointing crowns  258 A in  FIGS. 18A-G , as compared to  FIGS. 16A-G  where the clot  270 B enters the distal body interior  222  in an enlarged cell/drop zone  262 C immediately distal to one of the distal, unattached distal-pointing crowns  258 C). First, as always, the surgeon determines the location of the clot  270 B in the vessel  266  using, for example, a contrast dye injected proximal and distal to the clot  270 B. Next, the delivery catheter  208 , which is enveloping the distal body  216 , is positioned in the blood vessel  266  so that the two proximal, unattached distal-pointing crowns  258 A and  258 B are immediately distal to the clot  270 B. See  FIG. 18B . The distal body  216  is then deployed from the catheter  208  by moving the catheter  208  proximally. The hard clot  270 B, which is located above the distal body  216 , collapses the distal body  216 , as shown in  FIG. 18C . However, at this time, the surgeon is unaware that the clot  270 B has collapsed the distal body  216 . Thus, without moving the distal body  216 , the surgeon irradiates the x-ray markers at a first vantage point (i.e., from the front of the distal body in Orientation  2 ; into the page). As shown in  FIG. 18D , the first vantage point shows four rows of x-ray markers. The first row is, as always, a single point, representing the x-ray marker located in the proximal tube  228 ,  244 . The second row has only one point because the clot  270 B, which is on top of the second row of x-ray markers  258 A,  244  and  258 B,  244  (i.e., the markers at the proximal, unattached distal-pointing crowns), has pushed them together. The third row has only one point, which represents the x-ray marker located at the front (in Orientation  2 ), proximal, unattached distal-pointing crown  258 C,  244 ; the reason that this third row of markers is a single point is that the rear (in this view) x-ray marker of the third row  258 D,  244  is hidden from view because it is directly behind the front x-ray marker of the third row  258 C,  244 . The fourth row is, as always, a single point, representing the x-ray marker located in the distal tube  236 ,  244 . Without moving the distal body, the surgeon then irradiates the markers from a second vantage point 90 degrees offset from the first vantage point (i.e., from the bottom of the distal body  216 ). As shown, the first row is, as always, a single point, which represents the x-ray marker located in the proximal tube  228 ,  244 . The second row has a single point because the top (in Orientation  2 ) x-ray marker of the second row  258 A,  244  is located behind the bottom (in Orientation  2 ) x-ray marker  258 B,  244  and thus, the top x-ray marker of the second row  258 A,  244  is hidden from view. The third row has two points, which represents the x-ray markers located at the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244 ; in this x-ray view neither of the x-ray markers of the third row is hidden from view. The fourth row is, as always, a single point, which represents the x-ray marker located in the distal tube  236 ,  244 . The surgeon, thus, concludes that the second row of x-ray markers  258 A,  244  and  258 B,  244  (i.e., the x-ray markers at the proximal, unattached distal pointing-crowns) has converged. As shown in  FIG. 18E , the surgeon then moves the distal body  216  proximally so that the distal, unattached distal-pointing crowns  258 C,  244  and  258 D,  244  are immediately distal to the clot  270 B. Unbeknownst to the surgeon, the clot  270 B enters the distal body interior  222  immediately distal to the top (in Orientation  2 ), proximal unattached distal-pointing crown  258 A and the distal body  216  is no longer collapsed. The surgeon then irradiates the x-markers again from the first vantage point. As shown in  FIG. 18F , the first row is, as always, a single point, representing the x-ray marker located in the proximal tube  228 ,  244 . The second row has two x-ray markers because the distal body  216  is not collapsed and neither the top (in Orientation  2 )  258 A,  244  nor the bottom  258 B,  244  (in Orientation  2 ) x-ray marker of the second row (i.e., the marker at the proximal, unattached distal-pointing crowns) is hidden from view. The third row has only one point because the rear (in Orientation  2 ), distal unattached distal-pointing crown  258 D,  244  is hidden behind the front (in Orientation  2 ), distal, unattached distal pointing-crown  258 C,  244 . The fourth row is, as always, a single point, representing the x-ray marker located in the distal tube  236 ,  244 . Without moving the distal body  216 , the surgeon then irradiates the markers from a second vantage point 90 degrees offset from the first vantage point (i.e., from the bottom of the distal body  216 ). As shown, the first row is, as always, a single point, which represents the x-ray marker located in the proximal tube  228 ,  244 . The second row has a single point because the x-ray marker at the top (in Orientation  2 ), proximal, unattached distal-pointing crown  258 A,  244  is hidden behind the bottom (in Orientation  2 ), proximal, unattached-distal pointing crown  258 B,  244 . The third row has two points because neither the front nor the rear x-ray markers at the distal, unattached, distal-pointing crowns  258 C,  244  and  258 D,  244  is hidden from view. The fourth row is, as always, a single point, which represents the x-ray marker located in the distal tube  236 ,  244 . Based on the information from  FIGS. 18D and 18F , the surgeon concludes that the clot  270 B has entered into the distal body interior  222 . The surgeon then removes the distal body  216  and the hard clot  270 B, captured by the distal body  216 , by moving the distal body  216  proximally out of the vessel  266 , as shown in  FIG. 18G . Upon comparing  FIGS. 16A-G  and  FIGS. 18A-G  it will be appreciated that the orientation of the enlarged cells/drop zone  262 A-D relative to the orientation of a hard clot  270 B determine which enlarged cell/drop zone  262 A,  262 B,  262 C, or  262 D, the hard clot  270  enters the distal body interior  222  through. For example, in  FIG. 16C , the hard clot  270 B is located above the distal body  216 , and thus, the hard clot  270 B must enter through the enlarged cell/drop zone located at the top of the distal body, which in the orientation of the distal body shown in  FIGS. 16A-G , is the enlarged cell/drop zone  262 C immediately distal to the top, distal, unattached, distal-pointing crown  258 C. In  FIG. 18C , the hard clot  270 B is again located above the distal body and, thus, the hard clot  270 B must enter through the enlarged cell/drop zone located at the top of the distal body. However, in  FIG. 18C , the enlarged cell/drop zone located at the top of the distal body  216 , in the orientation of the distal body  216  shown in  FIGS. 18A-G , is the enlarged cell/drop zone  262 A immediately distal to the top, proximal, unattached, distal-pointing crown  258 A. 
       FIGS. 19A-N  illustrate stepwise use of the distal body  216  in retrieving a deformable cohesive, adherent clot  270 C—i.e., a clot that is difficult to break up and is tightly adhered to the vessel wall  268 —in a human intracranial artery  266 . (In  FIGS. 19A-N , the distal body  216  is in Orientation  2 ). First, as always, the surgeon determines the location of the clot  270 C in the vessel  266  using, for example, a contrast dye injected proximal and distal to the clot  270 C. Next, the delivery catheter  208 , which is enveloping the distal body  216 , is positioned in the blood vessel  266  so that the two proximal, unattached distal-pointing crowns  258 A and  258 B are immediately distal to the clot  270 C. See  FIG. 19B . The distal body  216  is then deployed from the catheter  208  by moving the catheter  208  proximally. The deformable, cohesive adherent clot  270 C, which is located above the distal body  216 , collapses the distal body  216 , as shown in  FIG. 19C . However, at this time, the surgeon is unaware that the clot  270 C has collapsed the distal body  216 . Thus, without moving the distal body  216 , the surgeon irradiates the x-ray markers at a first vantage point (i.e., from the front of the distal body; i.e., into the page). As shown in  FIG. 19D , the first vantage point shows four rows of x-ray markers. The first row is, as always, a single point, representing the x-ray marker located in the proximal tube  228 ,  244 . The second row has a single point, corresponding to the top (in Orientation  2 ) and bottom (in Orientation  2 ), proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244 , which have converged because the clot  270 C is collapsing the distal body  216 . The third row has a single point, which represents the x-ray marker located at the front (in Orientation  2 ), distal, unattached distal-pointing crown  258 C,  244 ; the x-ray marker located at the rear, distal, unattached distal-pointing crown  258 D,  244  is hidden from view. The fourth row is, as always, a single point, representing the x-ray marker located in the distal tube  236 ,  244 . Without moving the distal body  216 , the surgeon then irradiates the markers from a second vantage point 90 degrees offset from the first vantage point (i.e., from the bottom of the distal body). As shown, the first row is, as always, a single point, which represents the x-ray marker located in the proximal tube  228 ,  244 . The second row has a single point, which corresponds to the bottom (in Orientation  2 ), proximal, unattached distal-pointing crown  258 B,  244 ; the top (in Orientation  2 ), proximal, unattached distal-pointing crown  258 A,  244  is located behind the bottom, proximal, unattached distal-pointing crown  258 B,  244  and hidden from view. The third row has two points, which correspond to the front (in Orientation  2 )  258 C,  244  and rear  258 D,  244  (in Orientation  2 ), distal, unattached distal-pointing crowns, neither of which is blocked in this view. The fourth row is, as always, a single point, which represents the x-ray marker located in the distal tube  236 ,  244 . As shown in  FIG. 19E , the surgeon then moves the distal body  216  proximally (i.e., slightly withdraws the distal body  216 ). The surgeon then irradiates the x-markers again from the first and second vantage points. As shown in  FIG. 19F , the results are exactly the same as in  FIG. 19D . Based on the observation that the proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244  have converged at both the original position ( FIGS. 19C and 19D  in which the proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244  are immediately distal to the clot  270 C) and the second position ( FIGS. 19E and 19F ), the surgeon concludes that the clot  270 C is a deformable cohesive, adherent clot  270 C. The surgeon then oscillates the distal body  216  proximally and distally a small distance (e.g., about 1 mm to about 2 mm) in the vessel  266 , and the clot  270 C begins to enter the distal body  216 , as shown in  FIG. 19G . The surgeon then irradiates the x-markers again from the first and second vantage points. As shown in  FIG. 19H , the results are exactly the same as in  FIG. 19D  and  FIG. 19F  except that the second row of markers  258 A,  244  and  258 B,  244  (at the proximal, unattached distal-pointing crowns) are beginning to move apart. The surgeon then moves the distal body  216  proximally again, as shown in  FIG. 19I . The surgeon then irradiates the x-markers again from the first and second vantage points. As shown in  FIG. 19J , the results are exactly the same as in  FIGS. 19D and 19F , as the clot  270 C has caused the second row of markers  258 A,  244  and  258 B,  244  to re-converge. The surgeon then oscillates the distal body  216  proximally and distally a small distance (e.g., about 1 mm to about 2 mm) in the vessel  266 , and the clot  270 C begins to further enter the distal body interior  222 , as shown in  FIG. 19K . The surgeon then irradiates the x-markers again from the first and second vantage points. As shown in  FIG. 19L , the results are the same as in  FIG. 19H . The surgeon then moves the distal body  216  again proximally, and, instead of collapsing the second row of markers  258 A,  244  and  258 B,  244 , the clot  270 C fully enters the distal body interior  222 , as shown in  FIG. 19M . The surgeon then irradiates the x-markers again from the first and second vantage points. As shown in  FIG. 19N , the results show that the second row of markers  258 A,  244  and  258 B,  244  (at the proximal, unattached distal-pointing crowns) have moved apart. Satisfied that the x-ray markers in the second row  258 A,  244  and  258 B,  244  (at the proximal, unattached distal-pointing crowns) are sufficiently far apart and that the x-ray markers in the third row (at the distal, unattached distal-pointing crowns)  258 C,  244  and  258 D,  244  have stayed far apart, the surgeon concludes that the deformable cohesive, adherent clot  270 C has been sufficiently captured by the distal body  216  and the surgeon then removes the distal body  216  and the clot  270 C, captured by the distal body  216 , by moving the distal body  216  proximally out of the vessel  266 . 
     Several observations can be made from  FIGS. 15-19 , as indicated above. For example, the x-ray markers at the proximal and distal, unattached distal-pointing crowns  258 A-D,  244  provide the surgeon feedback concerning the interaction between the distal body  216  and the clot  270  in the blood vessel  266 . In addition, the guiding principle of a soft clot  270 A is that the soft clot  270 A does not collapse the distal body  216 , and thus, x-ray markers at the proximal and distal, unattached distal-pointing crowns  258 A-D,  244  always appear as two points except when a marker is hidden behind another marker (due to the view). When it comes to a hard clot  270 B, the hard clot  270 B is generally able to enter the distal body interior  222  without needing to oscillate the distal body  216  proximally and distally (unlike a deformable cohesive, adherent clot  270 C). However, to capture the hard clot  270 B, the hard clot  270 B must be oriented properly relative to the enlarged cell/drop zones  262 A,  262 B,  262 C, or  262 D. (This is the reason that the distal body  216  has four enlarged cells/drop zones: one enlarged cells/drop zone at 0 degrees  262 B, one enlarged cells/drop zone at 90 degrees  262 C, one enlarged cells/drop zone at 180 degrees  262 A and one enlarged cells/drop zone at 270 degrees  262 D). As a guiding principle, an enlarged cell/drop zone  262 A,  262 B,  262 C, or  262 D is properly oriented to the clot  270 B when the x-ray markers at the proximal, unattached distal-pointing crowns  258 A,  244  and  258 B,  244  or the distal, unattached distal pointing crowns  258 C,  244  and  258 D,  244  are together at both a first x-ray view and a second x-ray view 90 degrees relative to the first x-ray view, and the hard clot  270 B can enter the enlarged cell/drop zone  262 A,  262 B,  262 C, or  262 D by moving the distal body  216  proximally. See  FIGS. 16F and 18D . Finally, the guiding principal of retrieval of deformable cohesive, adherent clots  270 C is that oscillation of the distal body  216  causes the deformable cohesive, adherent clots  270 C to gradually enter the distal basket interior  222  over time. 
       FIGS. 20A, 20B and 20C  show a distal body  216  that is similar to the distal body  216  of  FIGS. 14A, 14B and 14C  except that the distal body  216  of  FIGS. 20A, 20B and 20C  is slightly shorter and its unattached, distal-pointing crowns  258 A,  258 B,  258 C, and  258 D are closer to the proximal tube  228 . The shortened distal body  216  of  FIGS. 20A, 20B and 20C  is particularly adapted for tortuous blood vessels  266 .  FIG. 21-29  show stepwise deployment of the distal body  216  of  FIGS. 20A, 20B and 20C  in use with a manual (i.e., hand-operated), volume-dependent (i.e. volume locked) suction catheter  272  that is locked at between about 10 to about 60 cubic centimeters (cc). Optionally, the suction catheter  272  has an outer diameter of between about 0.05 inches and about 0.09 inches and its outer diameter is substantially larger than the outer diameter of the delivery catheter  208 . The clot  270  is located in the vessel  266  through the use of, for example, contrast dye injected proximal and distal to the clot  270 . As shown in  FIG. 21 , a delivery catheter  208  containing the distal body  216  of  FIGS. 20A, 20B and 20C  is positioned in the tortuous vessel  266  distal to the clot  270 . The delivery catheter  208  is withdrawn, deploying the distal body  216 . See  FIG. 22 . The distal body  216  is moved proximally relative to the clot  270  and tension is exerted on pull wire  202 . See  FIG. 23 . While maintaining tension on the pull wire  202 , a suction catheter  272  having a proximal end  274  and a distal end  276  is delivered over the pull wire  202  that is attached to the distal body  216 . See  FIG. 24 . (The reason for exerting tension on the pull wire  202  is that the pull wire  202  serves as the guide/track for the movement of the suction catheter  272  and without tension, the suction catheter  272  and pull wire  202  could end up in the ophthalmic artery  288 ). The distal end  276  of the suction catheter  272  is positioned against the clot  270 . A syringe  278  is attached to the suction catheter  272  using a rotating hemostatic valve  290 , which allows the surgeon to aspirate while a pull wire  202  is in the system. The surgeon aspirates the syringe  278  by pulling back on the lever  280  to a mark on the base  282  corresponding to between about 10 and about 60 cubic centimeters of fluid. The surgeon then locks the lever  280  (and attached plunger) into place, leaving the suction catheter  272  under suction. The surgeon captures the clot  270  in the distal body  216  using the techniques described in  FIGS. 15-19 . The distal body  216  and clot  270  become captured by the suction catheter  272 . See  FIGS. 27 and 28 . The surgeon then removes the suction catheter  272  and the distal body  216  and the clot  270 , captured by the suction catheter  272 , by moving the suction catheter  272  proximally out of the vessel  266 . See  FIG. 29 . It is believed that the suction catheter  272  would be helpful in the event that a small portion of the clot  270  breaks off when retrieving the clot  270  using the distal body  216 . 
     To examine effectiveness of the systems  200 , the systems  200  of  FIGS. 11-20 , without the use of a suction catheter  272 , were used to retrieve soft and hard clots  270 A and  270 B induced in a pig weighing between 30 to 50 kg. The weight of the pig was chosen so that the size of its vessels  266  would be approximate to the size of a human vessel. The pig was anesthetized. Several hard clots  270 B were prepared by mixing pig blood and barium and incubating the mixture for 2 hours. Several soft clots  270 A were prepared by mixing pig blood, thrombin and barium and incubating the mixture for 1 hour. The clots  270 A and  270 B, each of which had a width of 4 to 6 mm and a length of 10 to 40 mm, were then inserted into a vessel  266  having a diameter of 2 to 4 mm. (Only one clot  270 A and  270 B was located in the vessel  266  at a time). Angiograms were then performed to confirm occlusion. After waiting ten minutes after confirming occlusion, the distal bodies  216  of  FIGS. 11-20  were then delivered distal to the clots  270 A and  270 B as described above and were used to retrieve the clots  270 A and  270 B as described in  FIGS. 11-19 . In each case, the distal bodies  216  were successful in retrieving the clots  270 A and  270 B. 
     The Embodiments of FIGS.  30 - 35   
       FIGS. 30-35  illustrate additional embodiments of object retrieval system. Optionally, the system  300  of  FIGS. 30-35  includes: 
     a pull wire  308  having a proximal end  310 , a distal end  312  and a pull wire longitudinal axis  314  extending from the proximal end  310  to the distal end  312 ; 
     a coaxial sheath/tube  316  having a hollow interior, an open proximal end  318  leading to the hollow interior, and an open distal end  320  leading to the hollow interior, the coaxial sheath  316  enveloping the pull wire  308 , the coaxial sheath  316  slideable along at least a segment of the pull wire  308 ; 
     a distal basket  322  comprising an interior  324 , a proximal end  326 , a distal end  328 , a distal basket length  330  extending from the distal basket proximal end  326  to the distal basket distal end  328 , a distal basket height  332  perpendicular to the distal basket length  330 , a plurality of proximal cells  336  defined by a plurality of proximal cell memory metal strips  338 , each proximal cell  336  comprising a proximal crown  340  located at the proximal end of the proximal cell  336  and pointing generally in the proximal direction and a distal crown  342  located at the distal end of the proximal cell  336  and pointing generally in the distal direction, and a plurality of distal cells  350  distal to the proximal cells  336 ; 
     a plurality of proximal strips  352 , each proximal strip  352  having a proximal end  354  extending from the coaxial sheath distal end  320 , a distal end  356  attached to a proximal crown  340  of a proximal cell  336  and a length  358  extending from the proximal end  354  to the distal end  356 ; and 
     a delivery catheter  360 , as described above, and having a hollow interior  366 , a proximal end  362  leading to the interior  366  and a distal end  364  leading to the interior  366 , the delivery catheter  360  comprised of a biocompatible material. 
     Optionally, the distal basket  322  is comprised of a memory metal and has: 
     a relaxed state in which the distal end  320  of the coaxial sheath  316  is located a first distance proximal to the proximal crowns  336  and wherein the distal basket  322 , as measured at the proximal-most crown  336 , has a first height, 
     a proximal collapsed state in which the distal end  320  of the coaxial sheath  316  is located a second distance proximal to the proximal crowns  336  and wherein the distal basket  322 , as measured at the proximal-most crown  336 , has a second height, the second distance greater than the first distance, the second height less than the first height, and 
     a distal collapsed state in which the distal end  320  of the coaxial sheath  316  is located distal to the proximal crowns  336  and in the basket interior  324  and wherein the distal basket  322 , as measured at the proximal-most crown  336 , has a third height, the third height less than the first height, 
     wherein the delivery catheter  366  is configured to envelope the distal basket  322  when the distal basket  322  is in the proximal collapsed state; 
     wherein the distal basket  322  is configured to move from the relaxed state to the proximal collapsed state by moving the distal end  320  of the coaxial sheath  316  proximally relative to the proximal crowns  336 ; and 
     wherein the distal basket  322  is configured to move from the relaxed state to the distal collapsed state by moving the distal end  320  of the coaxial sheath  316  distally beyond the proximal crowns  336  and into the distal basket interior  324 . 
     Optionally, each proximal crown  340  comprises a proximal tip  344  and further wherein each proximal strip  352  is configured to cover a proximal tip  344  when the distal basket  322  is in the distal collapsed state. See  FIG. 35C , where the proximal strip  352  is folding back on itself to cover the proximal tip  344 . Optionally, each proximal crown  340  comprises an eyelet  370  and further wherein each proximal strip  352  passes through an eyelet  370 . Optionally, the distal end  356  of each proximal strip  352  comprises a loop  372  attaching the proximal strip  352  to an eyelet  370 . Optionally, each proximal crown  340  has an interior surface  348  facing the distal basket interior  324  and an exterior surface  350  opposite the interior surface  348  and further wherein each proximal strip  352  contacts an exterior surface  350  of a proximal crown  340  in the proximal collapsed state and the distal collapsed states, as best seen in  FIGS. 35A-C . Without being bound to any particular theory, it is believed that threading the proximal strips  352  through the eyelets  370  as shown in  FIGS. 35A-35C , helps protect the proximal crowns  340  (in particular, the proximal tips  344  of the proximal crowns  340 ) from damaging the vessel wall  306  when the proximal crowns  340  move towards each other and the pull wire  308  when the distal basket  322  moves to the distal collapsed state and the proximal collapsed state. Optionally, the pull wire  308  extends through the distal basket interior  324  and further wherein the proximal crowns  340  are configured to move towards each other and towards the pull wire  308  when the distal basket  322  moves from the gaping state to the distal collapsed state. Optionally, the proximal crowns  340  are configured to remain a fixed distance from the distal end  328  of the distal basket  322  when the distal basket  322  moves from the relaxed state to the distal collapsed state. In other words, preferably, the distal basket length  330  does not change when the distal basket  322  moves from the distal basket relaxed state to the distal basket. Optionally, the coaxial sheath  316  is a braided catheter comprised of a plurality of braids and further wherein the proximal segments of the braids are wound/woven together to form the braided catheter and further wherein an unwound/unwoven distal segment of each braid forms a proximal strip  352 , as shown in  FIG. 34 . Optionally, at least one component of the system  300  (e.g., the proximal crown  340  or the distal tube  334 ) comprises an x-ray marker  374  that is more visible under x-ray as compared to the other components when the distal basket  322  is located in a cranial blood vessel  304  inside the body of a human and the x-ray is taken from outside the human&#39;s body. Preferably, the x-ray marker  374  is a radiopaque material. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with radiopaque filler, and the like. Preferably, the non x-ray marker components are comprised of nitinol and the x-ray marker  374  is comprised of a material having a density greater than the nitinol. In some embodiments, as shown in  FIGS. 30A, 30B, 31A, 31B, 32A -F, the proximal ends  354  of the proximal strips  352  are integral with the coaxial sheath  316 . In other embodiments, as shown in  FIG. 33 , the proximal ends  354  of the proximal strips  352  are attached to the coaxial sheath  316 . Optionally, the system  300  comprises between two and four proximal strips  352  and the proximal strips  352  are spaced substantially evenly apart (e.g., if there are two proximal strips  252 , the strips are located about 180 degrees relative to each other, as shown in  FIG. 30D ; if there are three proximal strips  252 , the strips are located about 120 degrees relative to each other, as shown in  FIG. 30C ; and if there are four proximal strips  252 , the strips are located about 1200 degrees relative to each other, as shown in  FIG. 30E ). Optionally, the proximal strips  352  have a length  358  of from about 5 mm to about 40 mm in the relaxed state. Optionally, the pull wire  308  extends through the basket interior  324  from the distal basket proximal end  326  to the distal basket distal end  328 . Optionally, the coaxial sheath interior has a size and shape, and further wherein the size and shape of the coaxial sheath interior are configured to prevent a segment  376  of the pull wire  308  located in the basket interior  322  and distal relative to the distal end  320  of the coaxial sheath  316  from moving through the coaxial sheath interior. In other words, optionally the pull wire  308  has a stop  376  that consists of a knot or other enlargement. Optionally, the distal end  328  of the distal basket  322  comprises a distal tube  334  having an open proximal end and an open distal end, the distal tube  334  comprised of a memory metal. Optionally, the distal tube  334  is attached to the pull wire  308  so that the distal tube  334  is not slideable along the pull wire  308 . This allows the entire distal basket  322  to be fixed to (i.e., not slideable along) the pull wire  308 . Optionally, wherein all proximal crowns  340  of the proximal cells  336  are attached to a proximal strip  352 , which is designed to minimize damage to the vessel wall  306 . Optionally, the distal basket  322  further comprises a lead wire  378  extending distally from the distal basket  322 . Optionally, the proximal strips  352  and the distal basket  322  have a different material composition. In other words, whereas the proximal strips  352  are designed to be soft, preferably, the distal basket  322  is comprised of a memory metal such as nitinol. Optionally, the proximal strips  352  are comprised of a polymer, which as used herein includes a co-polymer. Optionally, the polymer is selected from the group consisting of fluorinated ethylene propylene, polytetrafluoroethylene, and tetrafluoroethylene. Optionally, the proximal strips  352  are comprised of a material selected from the group consisting of plastic, rubber, nylon, suture material, and braided catheter material. 
     Optionally, as illustrated in  FIGS. 32A-32F , the system  300  is used in method of removing a clot  302  from a blood vessel  304  of an animal, the blood vessel  304  having an interior wall  306  forming the blood vessel  304 , the method comprising the steps of: 
     a) providing the system  300 , wherein the coaxial sheath  316  is located in the catheter interior  366  and the distal basket  322  is located in the catheter interior  366  in a collapsed state; 
     b) positioning the catheter  360  in the blood vessel  304  (see  FIG. 32A ); 
     c) deploying the distal basket  322  from the distal end  364  of the catheter  360  so that the proximal crowns  340  of the proximal cells  336  are distal to the clot  302 ; 
     d) allowing the distal basket  322  to move to the relaxed state (see  FIG. 32B ; the coaxial sheath  316  is in the first position along the pull wire  308 ); 
     e) moving the distal end  320  of the coaxial sheath  316  distally along the pull wire  308  to the fourth position (see  FIG. 32C ; note that the proximal crowns  340  have remained in the same location and that the distal basket height  332 , as measured at the proximal-most crown  340 , has not decreased yet; preferably, an x-ray marker  374  on the pull wire  308  allows the surgeon to locate the fourth position); 
     f) moving the distal basket  322  and the coaxial sheath  316  proximally and capturing the clot  302  in the distal basket interior  324  (see  FIG. 32D ); 
     g) moving the coaxial sheath  316  further distally along the pull wire (i.e., at or near the third position; preferably, an x-ray marker  374  on the pull wire  308  allows the surgeon to locate the third position) so that the distal basket height  332 , as measured at the proximal-most crown  340 , decreases and the proximal crowns  340  move toward each other and towards the pull wire  308  (see  FIGS. 32D and 32E ; it will be appreciated that the proximal crowns  340  collapse like a claw in  FIGS. 31B, 32D and 32E  due to tension exerted on the crowns  340  by the proximal strips  352 , similar to the mechanism described in  FIGS. 3-10 ); and 
     h) moving the system  300  proximally out of the blood vessel  304 . 
     The Embodiments of FIGS.  36 - 44   
       FIGS. 36-44  further illustrate other embodiments of a modular, easy-to-manufacture platform of systems for retrieving hard clots and other objects in animal lumens. In some embodiments, the system includes a proximal tube, a distal tube, and a plurality of memory metal strips between the proximal and distal tubes. The plurality of memory metal strips form a wide range of basket designs. Preferably, the proximal tube, memory metal strips, and distal tube are derived from a standard, off-the-shelf single tube of memory metal (e.g., nitinol), with the proximal tube and distal tube having the same inner diameter and outer diameter as the native tube from which they were derived and with the basket formed by cutting the middle portion of the native tube and expanding and shape-setting this cut portion. Preferably, the proximal tube and distal tube have an outer diameter that is from about 0.02 inches to about 0.03 inches (e.g., about 0.027 inches) so that the device fits inside a standard microcatheter and an inner diameter that is from about 0.01 inches to about 0.02 inches. Preferably, there are no welded parts between the proximal tube and distal tube, which makes the system easy and cheap to reliably manufacture. The system also includes one or more catheters for deploying the system, and a first wire that is attached to the proximal tube and a second wire that is attached to the distal tube. Preferably, the system includes two catheters—a guide catheter and a microcatheter. The plurality of memory metal strips attached to the proximal hub include a plurality of proximal tether memory metal strips, which have a proximal end attached to the distal end of the proximal tube. 
     The present disclosure also provides a system for removing objects within an interior lumen of an animal. In some embodiments, the system includes 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end; 
     a distal basket attached to said pull wire, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a proximal tube located at said proximal end of the distal basket, said proximal tube comprising a hollow interior, a plurality of proximal tether memory metal strips, a row of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction, each proximal tether memory metal strip having a proximal end attached to said proximal tube, a distal end attached to a crown of a proximal cell and a length extending from said proximal end to said distal end, a row of distal crowns located distal to said proximal cells pointing in the distal direction, and further wherein the number of distal crowns in said row is twice the number of proximal crowns attached to said proximal tether memory metal strips, and a distal tube located at said distal end of said distal basket, 
     said distal basket having 
     a relaxed state wherein said distal basket has a first height and 
     a collapsed state wherein said distal basket has a second height, said second height less than said first height, and 
     a catheter having an interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said distal body when said distal basket is in said collapsed state. 
     Optionally, said proximal tether memory metal strips rotate about said pull wire longitudinal axis such that a distal end of a proximal tether memory metal strip is located between about 90 and about 270 degrees relative to said proximal end of the same proximal tether memory metal strip. Optionally, said proximal tether memory metal strips and said proximal cell memory metal strips each have a thickness and further wherein said thickness of said proximal tether memory metal strips is between about 100 to about 175 percent of the thickness of the proximal cell memory metal strips. Optionally, the length of said proximal tether memory metal strips is about 10 mm to about 20 mm in the relaxed state (and the length of the remainder of the basket is about 10 to about 20 mm in the relaxed state so that the total basket length is between about 20 to about 40 mm in the relaxed state). Optionally, said distal end of said pull wire is attached to said proximal tube. Some or all of the proximal crowns of said proximal cells may be attached to a proximal tether memory metal strip. Optionally, said distal basket further comprises a row of strut memory metal strips, each strut memory metal strip having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, the distal basket comprises between two and four proximal tether memory metal strips. Optionally, said proximal tether memory metal strips are integral with said proximal tube. Optionally, said distal body further comprises a lead wire extending distally from said distal tube. Optionally, said distal tube, said proximal tube, and said basket are comprised of a nitinol having the same material composition. Optionally, said distal body further comprises an x-ray marker. Optionally, said proximal and said distal tubes are generally cylindrical in shape and each has an outer diameter and an inner diameter, the inner diameter forming the apertures of the proximal and distal tubes and further wherein the outer diameters of the proximal and distal tubes are substantially the same size and further wherein the inner diameters of the proximal and distal tubes are substantially the same size. Optionally, the outer diameters of the proximal and distal tubes are from about 0.011 inches to about 0.054 inches, and further wherein the inner diameters of the proximal and distal tubes are from about 0.008 inches to about 0.051 inches. Optionally, the pull wire is generally cylindrical and further wherein the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Optionally, the first height is between about 2 millimeters and about 8 millimeters. 
     The present disclosure also provides a method of removing an object from an interior lumen of an animal, said lumen having an interior wall forming said lumen, the method comprising the steps of: 
     a) providing the system described above;
 
b) positioning the system in said lumen, said basket located in said catheter in said collapsed state;
 
c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction;
 
d) allowing said distal basket to move to said relaxed state;
 
e) moving said distal basket over said obstruction; and
 
f) removing said distal basket and said obstruction from said lumen.
 
     Optionally, said interior lumen is an intracranial artery and said obstruction is a blood clot. 
     In further embodiments, the system includes: 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end;
 
a proximal basket attached to said pull wire, said proximal basket comprising an interior, an exterior, a proximal end, a distal end, a proximal basket length extending from said proximal basket proximal end to said distal end, a proximal basket height perpendicular to said proximal basket length and said pull wire longitudinal axis, a proximal tube located at said proximal end of the proximal basket, said proximal tube comprising a hollow interior, a plurality of rows of cells, each cell defined by a plurality of memory metal strips, each cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction,
 
a distal basket attached to said pull wire, said distal basket comprising an interior, an exterior, a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a distal tube located at said distal end of the distal basket, said distal tube comprising a distal tube aperture, a plurality of rows of cells, each cell defined by a plurality of memory metal strips, each cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction,
 
a plurality of tether memory metal strips, each tether memory metal strip having a proximal end attached to a distal crown of a cell located at the distal end of said proximal basket and a distal end attached to a proximal crown of a cell located at the proximal end of said distal basket,
 
said proximal basket having
 
a relaxed state wherein said proximal basket has a first height and
 
a collapsed state wherein said proximal basket has a second height, said second height less than said first height and said second width less than said first width,
 
said distal basket having
 
a relaxed state wherein said distal basket has a first height and a first width and
 
a collapsed state wherein said distal basket has a second height and a second width, said second height less than said first height, and
 
a catheter having an interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said distal and said proximal basket when said baskets are in said collapsed state.
 
     Optionally, said tether memory metal strips rotate about said pull wire longitudinal axis such that a distal end of a tether memory metal strip is located between about 90 and about 270 degrees relative to said proximal end of the same proximal tether memory metal strip. 
     More particularly, with reference to  FIGS. 36-44  the present disclosure provides a deployable system, generally designated by the numeral  410 , for removing an obstruction such as a blood clot  417  or other object from a blood vessel  488  or other interior lumen of an animal. In addition to a blood clot  417 , the obstruction may be, for example, extruded coils during aneurysm treatment, intravascular embolic material such as onyx or other obstructions requiring mechanical intravascular removal from small distal vessels. In the drawings, not all reference numbers are included in each drawing for the sake of clarity. 
     One example of a deployable basket system  410  is shown in  FIGS. 37A-37B, 38A -E and  39 A. As shown in  FIGS. 31A-31E, 32G-32H and 35A , the system  410  includes a pull wire  443  having a proximal end  445 , a distal end  444  and a pull wire longitudinal axis  446  extending from said proximal end  445  to said distal end  444 . Optionally, the diameter of the pull wire  443  is between about 0.008 inches and about 0.051 inches. 
     The system  410  further includes a distal basket  411  attached to said pull wire  443 , said distal basket  411  comprising a proximal end  469 , a distal end  465 , a distal basket length  467  extending from said distal basket proximal end  469  to said distal end  465 , a distal basket height  461  perpendicular to said distal basket length  467  and said pull wire longitudinal axis  446 , a proximal hub  439  located at said proximal end  469  of the distal basket  411  and comprising a hollow interior  441 , said distal end  444  of said pull wire  443  attached to said proximal hub  439 , a plurality of proximal tether memory metal strips  457 , a plurality of proximal cells  436  defined by a plurality of proximal cell memory metal strips  466 , each proximal cell  436  comprising a proximal crown  438  located at the proximal end of the proximal cell  436  and pointing generally in the proximal direction and a distal crown  424  located at the distal end of the proximal cell  436  and pointing generally in the distal direction, each proximal tether memory metal strip  457  having a proximal end  455  attached to said proximal hub  439  (preferably said proximal hub distal end  440 ), a distal end  453  attached to a crown of a proximal cell  438  and a length  455  extending from said proximal end  455  to said distal end  453 , a plurality of distal cells  422  distal to the proximal cells  436 , and a distal hub  425  located at said distal end  465  of said distal basket, comprising a hollow interior  427  and attached to a proximal end of a leader wire  431 . Preferably, the proximal hub  439  and distal hub  425  are hollow tubes formed from the same tube of memory metal, as described below. In some embodiments, the basket  411  includes a first row of two crowns (i.e., the proximal crowns  438  of the proximal cells  436 ) and then subsequent repeating rows of twice as many crowns as compared to the number of proximal crowns  438  (i.e., four crowns) along the basket length  467 . 
     The system further includes a guide catheter  430  and a microcatheter  432 , which is wider and shorter than the guide catheter  430 , so that the microcatheter  432  can fit inside the guide catheter  430 . The microcatheter  432  has a hollow interior  415 , a proximal end  416  leading to said interior  415  and a distal end  414  leading to said interior  415 . The microcatheter  432  is comprised of a biocompatible material. For purposes of  FIGS. 36-44 , the terms “guide catheter”, “microcatheter” and “catheter” generally refers to any suitable tube through which the system  410  can be deployed. Preferably, the catheters are sterile and comprised of a biocompatible material (i.e., a material that does not irritate the human body during the course of a 45 minute operation that involves using the system  410  to remove a clot  417  from an intracranial blood vessel  488 ). The catheter can be any suitable shape, including but not limited to generally cylindrical. For purposes of the present invention, when it is said that the catheter envelopes the system  410 , it will be understood that the catheter envelopes at least one component of the system  410  (preferably, the distal basket  411 , the lead wire  431 , which is a wire that extends distally from the pull wire  443 , and the pull wire  443 ). In some embodiments, the microcatheter  32  is about 2.5 French in diameter. Optionally, the catheter is delivered to the region of the lumen that has the obstruction  417  as follows: a guide wire is delivered to the obstruction region past the obstruction  417 ; the catheter is delivered over the guide wire; the guide wire is removed; and the system  410  is delivered with its pull wire  443  and lead wire  431  through the catheter. Optionally, the pull wire  443  is used to push the system  410  through the catheter as well as to retrieve the distal basket  411  after capturing the obstruction  417  as described below. The system  410  may utilize a plurality of catheters as described above, such as, for example, a wider catheter that travels to the brain and a very flexible, smaller diameter microcatheter that is delivered from the first catheter and travels through the small arteries of the brain. 
       FIG. 37A  shows the distal basket  411  collapsed inside a microcatheter  432 . The distal basket  411  is in what&#39;s referred to as the collapsed state. In this state, the system  410  is able to be located inside the microcatheter  432  and the basket height  461  is collapsed. For purposes of  FIGS. 36-44 , the basket height  461  generally refers to the height at a particular location (e.g., at the proximal-most crown  438  of the distal basket  411  or the distal-most crown  500  of the proximal basket  433 ), it being understood that the height of the distal basket  411  and proximal basket  433  may vary along the distal basket length  467  and the length of the proximal basket  433 . 
     As shown in  FIGS. 36-44 , the distance  463  between the proximal hub  439  and distal hub  425  (i.e., the basket length  467 ) is generally longer in the collapsed state, as compared to the relaxed state. 
       FIG. 37B  shows the same basket system as  FIG. 37A , except that the basket  411  has been deployed from the distal end  414  of the microcatheter  432  by pulling the microcatheter  432  proximally. As shown in  FIG. 37B , the basket  411  is now in a relaxed state and the basket height  461  has increased. In the relaxed state exemplified, the basket length  467  and the distance  463  between the proximal and distal hubs  439  and  425  has decreased slightly as the basket  411  has relaxed. Optionally, the length of said proximal basket  467  is between about 20 and about 40 mm and the length  454  of said proximal tether memory metal strips  457  are between about 10 and about 20 mm in the relaxed state. 
       FIG. 38  illustrates use of the basket system shown in  FIG. 37  in an intracranial artery  488 . As shown in  FIG. 38A , first the guide catheter  430  is deployed proximal to the clot  417 . The microcatheter  432  is then advanced distally beyond the clot  417 . The basket  411  is collapsed inside the microcatheter  432 . Next, as shown in  FIG. 38B , the microcatheter  432  is moved proximally to deploy the basket  411  so that the proximal tether memory metal strips  457  are distal to the clot  417 . The basket  411  is now in the relaxed state. Next, as shown in  FIG. 38C , the user moves the basket  411  proximally over the clot  417 . 
       FIG. 39A  shows a close-up view of the proximal end of the basket  411 , including the proximal tube interior  441 , the attachment of the proximal tether memory metal strips  457  at the distal end  455  of the proximal hub  439 , and the proximal crowns  438  of the proximal cells  436 . In  FIG. 39A , all proximal crowns  438  of the proximal cells  436  are attached to a proximal tether memory metal strip  457 .  FIG. 39B  illustrates an alternative embodiment in which two proximal crowns  438   a  of a proximal cell  436  (the top and bottom crowns  438   a ) are attached to a proximal tether memory metal strip  457  and one proximal crown  438   b  of a proximal cell  436  is not attached to a proximal tether memory metal strip  457 . 
       FIG. 40  illustrates a similar to basket system  410  to the above systems. In  FIG. 40 , the proximal tether memory metal strips  457  are relatively thick (e.g., about 150% of the thickness of the proximal cell memory metal strips  466 ). 
     It will be noted that the proximal end of the system  410  is shown at the bottom end of  FIGS. 36-44  and the distal end of the system  410  is shown at the top end of  FIGS. 36-44  because a principal use of the system  410  is to remove a blood clot  417  from a human intracranial artery  488 , in which case the system  410  generally will enter the artery  488  at its proximal end by the surgeon entering the patient&#39;s body near the groin and pushing the catheter  432  towards the brain. The diameter of human arteries  488  generally decrease from their proximal end to their distal end. However, when used in other types of lumens, the distal basket  411  may be located proximally relative to the catheter  432  as the term proximally and distally are used in that lumen. 
       FIG. 41  illustrates another embodiment of a basket system  411  with a proximal basket  433  and a distal basket  411 . In this embodiment, the system  411  includes a proximal hub  439  (similar to the prior embodiments). The difference is that the tether memory metal strips  457  actually join the proximal basket  433  and the distal basket  411 . More particularly, the proximal basket  433  is comprised of a plurality of proximal cells  436  attached to the proximal hub  439  and a plurality of distal cells  422  and the distal basket is comprised of a plurality of proximal cells  436  attached to the proximal hub  439  (preferably to the proximal end  499  of the distal hub  425 ) and a plurality of distal cells  422  and the tether memory metal strips  457  join a distal crown  423  of a distal cell  422  of the distal basket  411  with a proximal crown  438  of a proximal cell  436  of the proximal basket  433 . 
       FIG. 42  illustrate an embodiment of the tether memory metal strips  457  rotating about said pull wire longitudinal axis  446  such that the distal end  453  of a proximal tether memory metal strip  457  is located between about 90 and about 270 degrees relative to said proximal end  455  of the same proximal tether memory metal strip  457 . In addition, the proximal tether memory metal strips  457  may rotate around their longitudinal axis  454  such that a distal end  453  of a proximal tether memory metal strip  457  rotates about 90 degrees around this tether longitudinal axis  454  from the distal end  453  to the proximal end  455  of the same proximal memory metal strip  457 .  FIGS. 43B and 43C  illustrates an exemplary embodiment, where the proximal end  455 A of the first proximal tether memory metal strip  457 A is located attached to the proximal tube  439  at the 12 o&#39;clock position and the distal end  453 A of the same proximal tether memory metal strip  457 A is attached to a proximal-most crown  439  at the 9 o&#39;clock position. In addition, the second proximal tether memory metal strip  457 B is located attached to the proximal tube  439  at the 6 o&#39;clock position and the distal end  453 B of the same proximal tether memory metal strip  457 B is attached to the other proximal-most crown  439  at the 3 o&#39;clock position.  FIGS. 43D and 43E  illustrate an exemplary embodiment of 180 degree rotation, where the proximal end  455 A of the first proximal tether memory metal strip  457 A is located attached to the proximal tube  439  at the 12 o&#39;clock position and the distal end  453 A of the same proximal tether memory metal strip  457 A is attached to a proximal-most crown  439  at the 6 o&#39;clock position. In addition, the second proximal tether memory metal strip  457 B is located attached to the proximal tube  439  at the 6 o&#39;clock position and the distal end  453 B of the same proximal tether memory metal strip  457   b  is attached to the other proximal-most crown  439  at the 12 o&#39;clock position. 
       FIGS. 44A-44E  illustrate a side, perspective view of stepwise deployment and use of a basket system  410  with a proximal basket  433  and a distal basket  411  in a blood vessel to retrieve a clot  417 . As shown, the distal basket  411  is deployed proximal to said clot  417  and said proximal basket  433  is deployed at said clot  417  so that said proximal basket  433  is at level of the clot. After allowing some time for clot debris to penetrate the proximal basket  433 , the basket system  433  is moved proximally toward said microcatheter  432 . See  FIGS. 44B and 44C . As shown in  FIG. 44D , the clot  417  falls moves medially into the void or space  498  between the proximal basket  433  and distal basket  411 . The system  410  continues to move proximally. The clot  477  is then located inside the distal basket  411 . See  FIG. 44E . The proximal basket  433  optionally has a length in the relaxed state of preferably from about 10 to about 20 mm, as measured from the proximal-most crown to the distal-most crown. 
     The proximal basket  433  is used to deploy the system  411  across the obstruction  417  and is the initial site where the clot  417  enters through the struts  452 . As the basket system  411  is pulled/dragged proximally, the site of the proximal tether memory metal strip  457  gives a relative “open” area  498  for the clot  417  to fall into in the lumen of the vessel  488 . The distal basket  411  captures the clot  417  that has entered into the system  410  either through the basket cell openings or at the level of proximal tether memory metal strips  457  and prevents embolization into distal vessels  480 . Preferably, the proximal basket  433  has two distal crowns  500  at the distal end of the proximal basket  433  that are attached to the proximal end  455  of the proximal tether memory metal strips  457  and then one or more rows of proximal cells  501 , with four cells in each row. 
     In some embodiments, the basket system  410  is prepared by a process that includes one or more of the following steps, as illustrated in  FIG. 36 : 
     a) providing a single tube  468  comprised of a memory metal such as nitinol, the single tube  468  having an exterior, a substantially hollow interior, a wall  482  separating the exterior from the substantially hollow interior, an open proximal end  474 , an open distal end  476 , a middle portion  478  between the open proximal end  474  and the open distal end  476  (see  FIG. 36A );
 
b) cutting the wall of the middle portion  478  with a laser  480  (see  FIG. 36B );
 
c) removing the pieces of the middle portion cut by the laser  480  to form a basket system  410  comprising a proximal tube  439  comprising a hollow interior  441  extending through said proximal tube  439 , said proximal tube having a proximal end  442  and a distal end  440 , a distal tube  425  comprising a hollow interior  441  extending through said distal tube  425 , and a middle portion  478  located between said proximal tube  439  and said distal tube  425  and comprising a plurality of proximal tether memory metal strips  457 , each proximal tether memory metal strip  457  having a proximal end  455  attached to the distal end  440  of the proximal tube  439  and a distal end  453 ;
 
d) altering the shape of the middle portion  478  using a mandrel and allowing the middle portion  478  to expand relative to the distal tube  476  and proximal tube  474  to form a distal basket  411  that includes a plurality of cells  422  and  436 ;
 
e) quenching the middle portion  478  at room temperature;
 
f) removing the mandrel from the middle portion  478 ;
 
g) mechanically or chemically electropolishing the middle portion  478  to remove oxides (see  FIG. 36C );
 
h) inserting a pull wire  443  to said proximal tube  439 ; and
 
i) attaching a leader wire  431  to said distal hub  425  (see  FIG. 36D ).
 
     In some embodiments, the middle portion  478  is expanded by heating the mandrel and the middle portion  478  by, for example, placing the mandrel and the middle portion  478  in a fluidized sand bath at about 500° C. for about 3 to about 7 minutes. As the middle portion  478  is heated, the heating causes the crystalline structure of the memory metal tube  468  to realign. Preferably, the mandrel is tapered (e.g., substantially conical or bullet in shape) so that the portion of the distal basket  411  formed from the middle portion  478  tapers from the proximal-most crown  438  to the distal end  466 . Preferably, the proximal and distal ends of the tube  474  and  476  are not shape set by the mandrel and are not cut by the laser  480  so that the proximal and distal ends  474  and  476  do not change in shape and only slightly expand in size under heating and return to the size of the native tube  468  after the heat is removed. Preferably, the laser cuts are programmed via a computer. To ensure that the laser cuts only one surface of the tube wall at the time (and not the surface directly opposite the desired cutting surface), the laser  480  is preferably focused between the inner and outer diameter of the desired cutting surface and a coolant is passed through the memory metal tube  468  so that the laser  480  cools before reaching the surface directly opposite the desired cutting surface. 
     The portions of the wall not cut by the laser  480  create the proximal and distal tubes  474  and  476  as well as the other components of the distal basket  411 , and memory metal strips  457  and  466 , as described. 
     Preferably, the memory metal selected for the native tube  468  has a heat of transformation below average human body temperature (37° C.) so that the distal basket  411  has sufficient spring and flexibility after deployment from the catheter  432  in the human blood vessel  88 . 
     In some embodiments, the native tube  468  (and hence the distal and proximal tubes  474  and  476 ) have an outer diameter of less than about 4 French, e.g., a diameter of about 1 to about 4 French. In some embodiments, the diameter of the pull wire  443  is between about 0.008 inches and about 0.051, as noted above, and in such embodiments, the diameter of the pull wire  443  may be approximately equal to the inner diameter  472  of the native nitinol tube  468 . 
     Without being bound by any particular theory, it is believed that manufacturing the distal basket  411  from a single memory metal tube  468  provides ease of manufacturing and safety from mechanical failure and provides tensile strength necessary for the system  410  to remove hard thrombus  417  and other obstructions. 
     Optionally, after step e, the basket  411  further comprises a row  448  of proximal cells  436 , each proximal cell  436  defined by a plurality of memory metal strips  466  and comprising a proximal crown  438  located at a proximal end of the cell  436  and pointing in the proximal direction and a distal crown  424  located at a distal end of the cell and pointing in the distal direction and further wherein each of said proximal crowns  438  of said proximal cells  436  is attached to a distal end  453  of a proximal tether memory metal strip  457 . Optionally, after step e, the basket  410  further comprises a row  447  of distal cells  422  located distal to said proximal cells  436  and connected to said distal crowns  424  of said proximal cells  436 , each distal cell  422  defined by a plurality of memory metal strips  466  and comprising a proximal crown  437  located at a proximal end of the cell  422  and pointing in the proximal direction and a distal crown  423  located at a distal end of the cell  422  and pointing in the distal direction, and further wherein the number of distal cells  422  is twice the number of proximal cells  436 . Optionally, after step e, the basket system  410  further comprises a row  449  of strut memory metal strips  452 , each strut memory metal strip  452  having a proximal end  451  attached to a distal crown  424  of a proximal cell  436  and a distal end  450  attached to a proximal crown  437  of a distal cell  422 . Optionally, the basket  411  comprises no welded components and said proximal tether memory metal strips  457  are integral with said proximal cell crowns  438 . 
     Optionally, after step e, the basket system  411  comprises between two and four proximal tether memory metal strips  457 . Optionally, prior to cutting the memory metal tube  468 , the memory metal tub  468  has an outer diameter  486  that is from about 0.011 inches to about 0.054 inches and an inner diameter  484  that is from about 0.008 inches to about 0.051 inches. Optionally, after step e), the proximal tube  439  and distal tube  425  have an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally, the method further includes placing said basket  411  inside a catheter  432  comprised of a biocompatible material. Optionally, the method further includes the steps of placing the basket  411  inside a lumen  488  of an animal and using the basket to retrieve an object  417  located inside said lumen  488 . 
     The Embodiments of FIGS.  45 - 62   
       FIGS. 45-62  illustrate additional embodiments of a modular, easy-to-manufacture platform of systems for retrieving hard clots and other objects in animal lumens. In some embodiments, the system includes a proximal tube, a distal tube, and a plurality of memory metal strips between the proximal and distal tubes. The plurality of memory metal strips form a wide range of basket designs. Preferably, the proximal tube, memory metal strips, and distal tube are derived from a standard, off-the-shelf single tube of memory metal (e.g., nitinol), with the proximal tube and distal tube having the same inner diameter and outer diameter as the native tube from which they were derived and with the basket formed by cutting the middle portion of the native tube and expanding and shape-setting this cut portion. Preferably, the proximal tube and distal tube have an outer diameter that is from about 0.02 inches to about 0.03 inches (e.g., about 0.027 inches) so that the device fits inside a standard microcatheter and an inner diameter that is from about 0.01 inches to about 0.02 inches. Preferably, there are no welded parts between the proximal tube and distal tube, which makes the system easy and cheap to reliably manufacture. The system also includes one or more catheters for deploying the system, a pull wire that passes through the hollow interior of the proximal tube, and a coaxial tube. Preferably, the system includes two catheters—a guide catheter and a microcatheter. The coaxial tube envelopes the pull wire, is slideable along at least a segment of the pull wire, and is attached to the proximal hub. The coaxial tube allows a user to move the proximal hub toward and away from the distal hub while keeping the distal hub stationary. Movement of the proximal hub toward and away from the distal hub causes conformational changes in the basket, including (depending on the basket design and the location of the proximal tube), collapsing the basket, expanding the basket, strengthening the basket, and moving the basket around the clot. The plurality of memory metal strips attached to the proximal hub include a plurality of proximal tether memory metal strips, which have a proximal end attached to the distal end of the proximal tube. The length and thickness of the proximal tether memory metal strips vary in the different embodiments described herein, which allows the surgical user to select from the various embodiments in the platform based on the features needed for the particular operation (e.g., vessel anatomy and hardness of the clot). 
     In some embodiments, the disclosure provides a system for removing objects within an interior lumen of an animal that includes 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end; 
     a distal basket attached to said pull wire, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a proximal hub located at said proximal end of the distal basket, said proximal hub comprising a hollow interior, said pull wire passing through said proximal hub hollow interior, said proximal hub slideable along at least a segment of the pull wire, a plurality of proximal tether memory metal strips, a plurality of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, each proximal tether memory metal strip having a proximal end attached to said proximal hub, a distal end attached to a crown of a proximal cell and a length extending from said proximal end to said distal end, a plurality of distal cells distal to the proximal cells, and a distal hub located at said distal end of said distal basket and comprising a hollow interior, 
     said distal basket having 
     a relaxed state in which said proximal hub is located a first distance proximal to said proximal crowns and wherein said distal basket has a first height, as measured at the proximal-most crown, 
     a gaping state in which said proximal hub is located a second distance from said proximal crowns and wherein has a second height, as measured at the proximal-most crown, said second height greater than said first height, said second distance less than said first distance, 
     a proximal collapsed state in which said proximal hub is located a third distance proximal to said proximal crowns and wherein said distal basket has a third height and a third width, as measured at the proximal-most crown, said third distance greater than said first distance, said third height less than said first height, 
     a catheter having a hollow interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said distal basket when said distal basket is in said proximal collapsed state; 
     wherein said distal basket is configured to move from said relaxed state to said gaping state by moving said proximal hub distally relative to said distal hub; and 
     wherein said distal basket is configured to move from said expanded state to said proximal collapsed state by moving said proximal hub proximally relative to said distal hub. 
     Optionally, the distal basket further comprises a distal collapsed state in which said proximal hub is located distal to said proximal crowns and wherein said distal basket has a fourth height, as measured at the proximal-most crown, said fourth height less than said first height, wherein said catheter is configured to envelope said distal basket when said distal basket is in said distal collapsed state, and further wherein said distal basket is configured to move from said gaping state to said distal collapsed state by moving said proximal hub distally relative to said distal hub. Optionally, the system further includes a coaxial tube, said coaxial tube configured to be received in said catheter, said coaxial tube having a proximal end, a distal end attached to said proximal hub, and a hollow interior, said pull wire passing through said coaxial tube hollow interior, said coaxial tube slideable along at least a segment of said pull wire. In some embodiments, said proximal tether memory metal strips and said proximal cell memory metal strips each have a thickness and further wherein said thickness of said proximal tether memory metal strips is between about 25 to about 75 percent of the thickness of the proximal cell memory metal strips. In such embodiments, the length of the proximal tether memory metal strips is between about 3 mm to about 10 mm in the relaxed state. In some embodiments with thin proximal tether memory metal strips, the combined length of two of said proximal tether memory metal strips is within about 2 mm of said second height. In other embodiments with thin proximal tether memory metal strips, the combined length of two of said proximal tether memory metal strips is within about 2 mm of said second height multiplied by a factor of two. 
     In other embodiments, the proximal tether memory metal strips are as thick or thicker than the memory metal strips forming the proximal cells and in such embodiments, the length of the proximal tether memory metal strips may be between about 10 mm and about 20 mm in the relaxed state. 
     Optionally, said pull wire extends from said distal basket proximal end to said distal basket distal end. Optionally, said pull wire is not in contact with said distal hub. Optionally, in said gaping state, said proximal hub is located parallel to said proximal crown. Optionally, said pull wire and said proximal hub are offset from the center of the distal basket height, as measured at the proximal-most crown. Optionally, all proximal crowns of said proximal cells are attached to a proximal tether memory metal strip. Optionally, said distal basket further comprises a plurality of strut memory metal strips and plurality of distal cells defined by a plurality of distal memory metal strips, said distal cells comprising a proximal crown located at a proximal end of said distal cells and a distal crown located at a distal end of said distal cells, said strut memory metal strips having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, the distal basket comprises between two and four proximal tether memory metal strips. Optionally, said proximal memory metal strips are integral with said proximal hub. Optionally, said proximal hub is a tube, wherein said interior of said proximal hub has a size and shape, and further wherein said size and shape of said proximal hub interior are configured to prevent a segment of said pull wire distal relative to said proximal hub from moving through proximal hub interior. Optionally, said distal hub is a tube. Optionally, said distal hub is attached to said pull wire such that said distal hub is not slideable along said pull wire. Optionally, said distal basket further comprises a lead wire extending distally from said distal hub. Optionally, said distal hub, said proximal hub, and said basket are comprised of a nitinol having the same material composition. Optionally, said distal basket further comprises an x-ray marker that is more visible under x-ray as compared to the other components when the distal basket is located in a cranial blood vessel inside the body of a human and the x-ray is taken from outside the human&#39;s body. Preferably, the x-ray marker is a radiopaque material. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with radiopaque filler, and the like. Preferably, the components are comprised of nitinol and the x-ray marker is comprised of a material having a density greater than the nitinol. Optionally, said proximal and said distal hubs are generally cylindrical in shape and each has an outer diameter and an inner diameter, the inner diameter forming apertures of the proximal and distal hubs and further wherein the outer diameters of the proximal and distal hubs are substantially the same size and further wherein the inner diameters of the proximal and distal hubs are substantially the same size. Optionally, the outer diameters of the proximal and distal hubs are from about 0.011 inches to about 0.054 inches, and further wherein the inner diameters of the proximal and distal hubs are from about 0.008 inches to about 0.051 inches. Optionally, the proximal tube and distal tube have an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally, the pull wire is generally cylindrical and further wherein the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Optionally, the first height is between about 2 millimeters and about 8 millimeters. Optionally, said proximal tether memory metal strips rotate about said pull wire longitudinal axis such that a distal end of a proximal tether memory metal strip is located between about 90 and about 270 degrees relative to said proximal end of the same proximal tether memory metal strip. 
     The present disclosure also provides a method of removing an object from an interior lumen of an animal, said lumen having an interior wall forming said lumen. In some embodiments, the method includes: 
     a) providing the system described above; 
     b) positioning the system in said lumen, said basket located in said catheter in a collapsed state; 
     c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction; 
     d) allowing said distal basket to move to said relaxed state; 
     e) moving said proximal hub distally relative to said distal hub so that said distal basket height, as measured at the proximal-most crown, increase; 
     f) moving said distal basket over said obstruction; and 
     g) removing said distal basket and said obstruction from said lumen. 
     Optionally, the interior lumen is an intracranial artery and said obstruction is a blood clot. Optionally, the method further comprises using said blood clot to move said proximal hub distally relative to said distal hub and allow said distal basket to move to said gaping state. Optionally, the method further comprises using a coaxial tube to push said proximal hub distally relative to said distal hub and allow said distal basket to move to said gaping state. Optionally, the method further includes, after step e, moving said proximal hub relative to said distal hub so that said distal basket height, as measured at the proximal-most crown, decrease. Optionally, after step e, said pull wire and said proximal hub are offset with respect to the center of said distal basket height, as measured at the proximal-most crown, as measured at the proximal-most crown, and the center of said lumen. 
     The present disclosure also provides a system for removing objects within an interior lumen of an animal, the system comprising: 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end; 
     a proximal basket attached to said pull wire, said proximal basket comprising a proximal end, a distal end, a proximal basket length extending from said proximal basket proximal end to said distal end, a proximal basket height perpendicular to said proximal basket length and said pull wire longitudinal axis, a proximal tube located at said proximal end of the proximal basket, said proximal tube comprising a hollow interior, said pull wire passing through said hollow interior and said proximal tube slideable along at least a segment of said pull wire, a plurality of rows of cells, each cell defined by a plurality of memory metal strips, each cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, 
     a distal basket attached to said pull wire, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a distal tube located at said distal end of the distal basket, said distal tube comprising a hollow interior, a plurality of rows of cells, each cell defined by a plurality of memory metal strips, each cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, 
     a plurality of tether memory metal strips, each tether memory metal strip having a proximal end attached to a distal crown of a cell located at the distal end of said proximal basket and a distal end attached to a proximal crown of a cell located at the proximal end of said distal basket, said proximal basket having 
     a relaxed state wherein said proximal basket has a first height as measured at the distal-most crown, and said proximal hub is located a first distance proximal to said distal hub; 
     a collapsed state wherein said proximal basket has a second height, as measured at the distal-most crown, said second height less than said first height; 
     a gaping state wherein said proximal basket has a third height, as measured at the distal-most crown, and said proximal hub is located a second distance proximal to said distal hub, said third height greater than said first height and said second distance less than said first distance, said proximal basket configured to move from said expanded state to said gaping state by pushing said proximal tube distally relative to said distal tube; 
     said distal basket having 
     a relaxed state wherein said distal basket has a first height and 
     a collapsed state wherein said distal basket has a second height, said second height less than said first height, and 
     a catheter having an interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said distal and said proximal basket when said baskets are in said collapsed state. 
     Optionally, said proximal tether memory metal strips rotate about said pull wire longitudinal axis such that a distal end of a proximal tether memory metal strip is located between about 90 and about 270 degrees relative to said proximal end of the same proximal tether memory metal strip. 
     In some embodiments, the system does not include a proximal hub and the system includes soft cords in place of or in addition to the proximal memory metal strips. For example, in one embodiment, the system includes: 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end; 
     a coaxial tube having a proximal end, a distal end and a hollow interior, said pull wire passing through said coaxial tube hollow interior, said coaxial tube slideable along at least a segment of said pull wire; 
     a distal basket attached to said pull wire and said coaxial tube, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a plurality of cords, a plurality of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, each cord having a proximal end attached to said coaxial tube, a distal end attached to a crown of a proximal cell and a length extending from said proximal end to said distal end, a plurality of distal cells distal to the proximal cells, and a distal hub located at said distal end of said distal basket and comprising a hollow interior, 
     said distal basket having 
     a relaxed state in which said coaxial tube is located a first distance proximal to said proximal crowns and wherein said distal basket, as measured at the proximal-most crown, has a first height, 
     a proximal collapsed state in which said coaxial tube is located a second distance proximal to said proximal crowns and wherein said distal basket, as measured at the proximal-most crown, has a second height, said second distance greater than said first distance, said second height less than said first height, 
     a catheter having a hollow interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said coaxial tube and said distal basket when said distal basket is in said proximal collapsed state; 
     wherein said distal basket is configured to move from said relaxed state to said proximal collapsed state by moving said coaxial tube proximally relative to said distal hub. 
     Optionally, the distal basket further comprises a distal collapsed state in which said coaxial tube is located distal to said proximal crowns and wherein said distal basket, as measured at the proximal-most crown, has a third height, said third height less than said first height, wherein said catheter is configured to envelope said distal basket when said distal basket is in said distal collapsed state, and further wherein said distal basket is configured to move from said relaxed state to said distal collapsed state by moving said coaxial tub distally relative to said distal hub. Optionally said cord is comprised of a material selected from the group consisting of plastic, rubber, nylon, suture material, and braided catheter material. Optionally, said cords are integral with said coaxial sheath. Optionally, said cords are glued to said coaxial sheath. Optionally, said cords are shrink wrapped to said coaxial sheath. Optionally, said cords have a thickness of from about 0.001 to about 0.1 inches (more preferably about 0.004 to about 0.018 inches) and have a length of from about 3 mm to about 20 mm in said relaxed state. Optionally, said pull wire extends from said distal basket proximal end to said distal basket distal end and said pull wire is attached to said distal hub. Optionally, all proximal crowns of said proximal cells are attached to a cord. Optionally, the basket comprises four proximal cells, each proximal cell having a proximal crown, and not all (e.g., only two) of the proximal crowns are attached to a cord. Optionally, said distal basket further comprises a plurality of strut memory metal strips and plurality of distal cells defined by a plurality of distal memory metal strips, said distal cells comprising a proximal crown located at a proximal end of said distal cells and a distal crown located at a distal end of said distal cells, said strut memory metal strips having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, the distal basket comprises between two and four cords. Optionally, said distal hub is attached to said pull wire such that said distal hub is not slideable along said pull wire. Optionally, said distal basket further comprises a lead wire extending distally from said distal hub. Optionally, said distal hub and said basket are comprised of a nitinol having the same material composition. Optionally, said distal basket and/or said coaxial tube further comprises an x-ray marker that is more visible under x-ray as compared to the other components when the distal basket is located in a cranial blood vessel inside the body of a human and the x-ray is taken from outside the human&#39;s body. Preferably, the x-ray marker is a radiopaque material. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with radiopaque filler, and the like. Preferably, the components are comprised of nitinol and the x-ray marker is comprised of a material having a density greater than the nitinol. Optionally, said distal hub is generally cylindrical in shape and has an outer diameter and an inner diameter, the inner diameter forming the aperture of the distal hub and further wherein the outer diameter of the distal hub from about 0.011 inches to about 0.054 inches, and further wherein the inner diameter of the distal hub is from about 0.008 inches to about 0.051 inches. Optionally, the distal tube has an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally, the pull wire is generally cylindrical and further wherein the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Optionally, the first height of the distal basket, as measured at the proximal-most crown, is between about 2 millimeters and about 8 millimeters. Optionally, said cords are soft. 
     In some embodiments, the present disclosure provides a method of removing an object from an interior lumen of an animal, said lumen having an interior wall forming said lumen, the method comprising the steps of: 
     a) providing the system described above; 
     b) positioning the system in said lumen, said basket located in said catheter in a collapsed state; 
     c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction; 
     d) allowing said distal basket to move to said relaxed state; 
     e) moving said coaxial tube distally relative to said distal hub so that said coaxial tube moves distally to the proximal-most crown; 
     f) moving said distal basket, said pull wire and said coaxial tube proximally so that said distal basket moves over said obstruction; 
     g) moving said coaxial sheath distally relative to said distal hub so that said distal basket height, as measured at the proximal-most crown, decreases and said coaxial tube is closer to said distal hub as compared to the proximal-most crown; and 
     i) removing said distal basket and said obstruction from said lumen. 
     In other embodiments, the method includes 
     a) providing the system described above; 
     b) positioning the system in said lumen, said basket located in said catheter in a collapsed state; 
     c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction; 
     d) allowing said distal basket to move to said relaxed state; 
     e) moving said coaxial tube distally relative to said distal hub so that said coaxial tube moves distally to the proximal-most crown; 
     f) moving said distal basket, said pull wire and said coaxial tube proximally so that said distal basket moves over said obstruction; 
     g) moving said coaxial sheath proximally relative to said distal hub so that said distal basket height, as measured at the proximal-most crown, decreases; 
     h) moving said catheter distally relative to said distal hub so that said catheter re-sheaths said coaxial sheath and partially re-sheaths said cords, thereby decreasing said distal basket height, as measured at the proximal-most crown; 
     i) removing said distal basket and said obstruction from said lumen. 
     Optionally, said interior lumen is an intracranial artery and said obstruction is a blood clot. 
     In other embodiments that do not include a proximal hub, the system includes 
     a pull wire having a proximal end, a distal end and a pull wire longitudinal axis extending from said proximal end to said distal end; 
     a coaxial tube having a proximal end, a distal end and a hollow interior, said pull wire passing through said coaxial tube hollow interior, said coaxial tube slideable along at least a segment of said pull wire; 
     a distal basket attached to said pull wire and said coaxial tube, said distal basket comprising a proximal end, a distal end, a distal basket length extending from said distal basket proximal end to said distal end, a distal basket height perpendicular to said distal basket length and said pull wire longitudinal axis, a plurality of proximal tether memory metal strips, a plurality of cords, a plurality of proximal cells defined by a plurality of proximal cell memory metal strips, each proximal cell comprising a proximal crown located at the proximal end of the proximal cell and pointing generally in the proximal direction and a distal crown located at the distal end of the proximal cell and pointing generally in the distal direction, each proximal tether memory metal strip having a proximal end attached to said coaxial tube and a distal end, each cord having a proximal end attached to a distal end of a proximal tether memory metal strip and a distal end attached to a crown of a proximal cell and a length extending from said proximal end to said distal end, and a plurality of distal cells distal to the proximal cells, and a distal hub located at said distal end of said distal basket and comprising a hollow interior, 
     said distal basket having 
     a relaxed state in which said distal basket, as measured at the proximal-most crown, has a first height, 
     a collapsed state in which said distal basket, as measured at the proximal-most crown, has a second height, said second height less than said first height, 
     a catheter having a hollow interior, a proximal end leading to said interior and a distal end leading to said interior, said catheter comprised of a biocompatible material and configured to envelope said coaxial tube and said distal basket when said distal basket is in said collapsed state. 
     Optionally, said cord is comprised of a material selected from the group consisting of plastic, rubber, nylon, suture material, and braided catheter material. Optionally, said proximal tether memory metal strips are integral with said coaxial sheath. Optionally, said cords are glued to said proximal tether memory metal strips. Optionally, said cords are shrink wrapped to said proximal tether memory metal strips. Optionally, said cords have a thickness of from about 0.004 to about 0.1 inches (more preferably about 0.004 inches to about 0.018 inches) and further wherein said cords have a length of from about 3 mm to about 20 mm in said relaxed state. Optionally, said pull wire extends from said distal basket proximal end to said distal basket distal end and said pull wire is attached to said distal hub. Optionally, all proximal crowns of said proximal cells are attached to a cord. Optionally, the basket comprises four proximal cells, each proximal cell having a proximal crown, and not all (e.g., only two) of the proximal crowns are attached to a cord. Optionally, said distal basket further comprises a plurality of strut memory metal strips and plurality of distal cells defined by a plurality of distal memory metal strips, said distal cells comprising a proximal crown located at a proximal end of said distal cells and a distal crown located at a distal end of said distal cells, said strut memory metal strips having a proximal end attached to a distal crown of a proximal cell and a distal end attached to a proximal crown of a distal cell. Optionally, the distal basket comprises between two and four cords. Optionally, said distal hub is attached to said pull wire such that said distal hub is not slideable along said pull wire. Optionally, said distal basket further comprises a lead wire extending distally from said distal hub. Optionally, said distal hub and said basket are comprised of a nitinol having the same material composition. Optionally, said distal basket and/or said coaxial tube further comprises an x-ray marker that is more visible under x-ray as compared to the other components when the distal basket is located in a cranial blood vessel inside the body of a human and the x-ray is taken from outside the human&#39;s body. Preferably, the x-ray marker is a radiopaque material. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with radiopaque filler, and the like. Preferably, the components are comprised of nitinol and the x-ray marker is comprised of a material having a density greater than the nitinol. Optionally, said distal hub is generally cylindrical in shape and has an outer diameter and an inner diameter, the inner diameter forming the aperture of the distal hub and further wherein the outer diameter of the distal hub from about 0.011 inches to about 0.054 inches, and further wherein the inner diameter of the distal hub is from about 0.008 inches to about 0.051 inches. Optionally, the distal tube has an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally the pull wire is generally cylindrical and further wherein the diameter of the pull wire is between about 0.008 inches and about 0.051 inches. Optionally, the first height of the distal basket, as measured at the proximal-most crown, is between about 2 millimeters and about 8 millimeters. Optionally, the cords are soft. 
     In some embodiments, the above system is used in a method of removing an object from an interior lumen of an animal, said lumen having an interior wall forming said lumen that includes 
     a) providing the above system; 
     b) positioning the system in said lumen, said basket located in said catheter in a collapsed state; 
     c) deploying said distal basket from said distal end of said catheter so that said proximal crowns of said proximal cells are distal to said obstruction, said coaxial sheath is proximal to said obstruction, said proximal tether memory metal strips are proximal to said obstruction, and said cords are adjacent to said obstruction; 
     d) allowing said distal basket to move to said relaxed state; 
     e) moving said coaxial tube distally relative to said distal hub so that said proximal tether memory metal strips move distally relative to the proximal-most crown and said obstruction is sandwiched between said proximal tether memory metal strips and said proximal crowns of said proximal cells; 
     f) removing said distal basket and said obstruction from said lumen. 
     Optionally said interior lumen is an intracranial artery and said obstruction is a blood clot. 
     With reference to  FIGS. 45-62  the present disclosure provides a deployable system, generally designated by the numeral  610 , for removing an obstruction such as a blood clot  617  or other object from a blood vessel  688  or other interior lumen of an animal. In addition to a blood clot  617 , the obstruction may be, for example, extruded coils during aneurysm treatment, intravascular embolic material such as onyx or other obstructions requiring mechanical intravascular removal from small distal vessels. In the drawings, not all reference numbers are included in each drawing for the sake of clarity. 
     One example of a deployable basket system  610  is shown in  FIGS. 46A-46E, 47G-47H and 50A . As shown in  FIGS. 46A-46E, 47G-47H and 50A , the system  610  includes a pull wire  643  having a proximal end  645 , a distal end  644  and a pull wire longitudinal axis  646  extending from said proximal end  645  to said distal end  644 . Optionally, the diameter of the pull wire  643  is between about 0.008 inches and about 0.051 inches. 
     The system  610  further includes a distal basket  611  attached to said pull wire  643 , said distal basket  611  comprising a proximal end  669 , a distal end  665 , a distal basket length  667  extending from said distal basket proximal end  669  to said distal end  665 , a distal basket height  661  perpendicular to said distal basket length  667  and said pull wire longitudinal axis  646 , a proximal hub  639  located at said proximal end  669  of the distal basket  611 , said proximal hub  639  comprising a hollow interior  641 , said pull wire  643  passing through said proximal hub hollow interior  641 , said proximal hub  639  slideable along at least a segment of the pull wire  643 , a plurality of proximal tether memory metal strips  657 , a plurality of proximal cells  636  defined by a plurality of proximal cell memory metal strips  666 , each proximal cell  636  comprising a proximal crown  638  located at the proximal end of the proximal cell  636  and pointing generally in the proximal direction and a distal crown  624  located at the distal end of the proximal cell  636  and pointing generally in the distal direction, each proximal tether memory metal strip  657  having a proximal end  655  attached to said proximal hub  639 , a distal end  663  attached to a crown of a proximal cell  638  and a length  655  extending from said proximal end  655  to said distal end  653 , a plurality of distal cells  622  distal to the proximal cells  636 , and a distal hub  625  located at said distal end  665  of said distal basket and comprising a hollow interior  627 . Preferably, the proximal hub  639  and distal hub  625  are hollow tubes formed from the same tube of memory metal, as described below. In some embodiments, the basket  611  includes a first row of two, three, or four crowns (i.e., the proximal crowns  638  of the proximal cells  638 ) and then subsequent repeating rows of twice as many crowns as compared to the number of proximal crowns  638  (i.e., four, six, or eight crowns) along the basket length  667 . 
     The system further includes a guide catheter  630  and a microcatheter  632 , which is wider and shorter than the guide catheter  630 , so that the microcatheter  632  can fit inside the guide catheter  630 . The microcatheter  632  has a hollow interior  615 , a proximal end  616  leading to said interior  615  and a distal end  614  leading to said interior  615 . The microcatheter  632  is comprised of a biocompatible material. As used herein, the terms “guide catheter”, “microcatheter” and “catheter” generally refers to any suitable tube through which the system  610  can be deployed. Preferably, the catheters are sterile and comprised of a biocompatible material (i.e., a material that does not irritate the human body during the course of a 45 minute operation that involves using the system  610  to remove a clot  617  from an intracranial blood vessel  688 ). The catheter can be any suitable shape, including but not limited to generally cylindrical. For purposes of the present invention, when it is said that the catheter envelopes the system  610 , it will be understood that the catheter envelopes at least one component of the system  610  (preferably, the distal basket  611 , the lead wire  631 , which is a wire that extends distally from the pull wire  643 , and the pull wire  643 ). In some embodiments, the microcatheter  632  is about 2.5 French in diameter. Optionally, the catheter is delivered to the region of the lumen that has the obstruction  617  as follows: a guide wire is delivered to the obstruction region past the obstruction  617 ; the catheter is delivered over the guide wire; the guide wire is removed; and the system  610  is delivered with its pull wire  643  and lead wire  631  through the catheter. Optionally, the pull wire  643  is used to push the system  610  through the catheter as well as to retrieve the distal basket  611  after capturing the obstruction  617  as described below. The system  610  may utilize a plurality of catheters as described above, such as, for example, a wider catheter that travels to the brain and a very flexible, smaller diameter microcatheter that is delivered from the first catheter and travels through the small arteries of the brain. 
     Preferably, a coaxial tube  618 , which has a hollow interior  620  and is slideable along at least a portion of the pull wire  643  is attached to the proximal hub  639 . 
       FIG. 46A  shows the distal basket  611  collapsed inside a microcatheter  632 . The distal basket  611  is in what&#39;s referred to as the proximal collapsed state. In this state, the system  610  is able to be located inside the microcatheter  632  and the basket height  661  is collapsed. For purposes of the present invention, the basket height  661  generally refers to the height at a particular location (e.g., at the proximal-most crown  638  of the distal basket  611  or the distal-most crown  623  of the proximal basket  633 ), it being understood that the height of the distal basket  611  and proximal basket  633  may vary along the distal basket length  667  and the length of the proximal basket  633 . 
     In  FIG. 46A , the proximal hub  639  is located a maximum distance from the distal hub  625 . The distance from the proximal hub  639  to the distal hub  625  changes by exerting force on the proximal hub  639 , as described herein, and the distance is shown in the drawings using the numeral  663 . This distance is also generally equal to the length of the basket  667 , as shown. 
       FIG. 46B  shows the same basket system as  FIG. 46A , except that the basket  611  has been deployed from the distal end  614  of the microcatheter  632  by pulling the microcatheter  632  proximally. As shown in  FIG. 46B , the basket  611  is now in a relaxed state and the basket height  661  has increased. In the relaxed state exemplified, the proximal tube  639  is located a short distance  629  proximal to the proximal-most crown  638 . In addition, the basket length  667  and the distance  663  between the proximal and distal hubs  639  and  625  has decreased as the basket  611  has relaxed. In addition, the user has moved the coaxial tube  618  proximally relative to the pull wire  643  as shown by the line in the lower part of  FIG. 46B , which indicates that the distance between the proximal stop  664  and the coaxial tube proximal end  621  has increased from  FIG. 46A  to  FIG. 46B . The present invention may utilize a variety of stops, such as a proximal stop  664 , which is any barrier that prevents the coaxial tube  618  from moving proximally beyond the proximal stop  664 . In some forms, the proximal stop  664  is merely an enlargement or x-ray marker  658  in the pull wire  643  that is taller and/or wider than the open coaxial tube interior  620  (i.e., the inner diameter of the coaxial tube  618 ). Instead of stops or in addition to stops, the pull wire  643  may be etched to provide guidance to the surgeon on the distance to push and pull the coaxial tube  618 . 
       FIG. 46C  exemplifies what is referred to as the gaping state of the basket  611 . To move the basket  611  from the relaxed state to the gaping state, a user merely pushes the proximal hub  639  distally towards the stationary distal hub  625 . This causes the proximal tether memory metal strips  657  to increase the height  661  of the distal basket  611  at the proximal-most crown  638 . The proximal tether memory metal strips  657  of the embodiment shown in  FIGS. 46, 47 and 50  are relatively short. The proximal tether memory metal strips  657  are relatively thin compared to the memory metal strips  666  that make up the proximal cells  636 , which makes the proximal tether memory metal strips  657  easy to bend. Preferably, in the gaping state of short, relatively thin proximal tether memory metal strips  657 , the proximal memory metal strips  657  are substantially perpendicular (e.g., about 75 to about 105 degrees) relative to the longitudinal axis of the pull wire  646 . 
       FIG. 46D  exemplifies what is referred to as the distal collapsed state. To move the basket  611  from the gaping state to the distal collapsed state, a user merely pushes the proximal hub  639  distally towards the stationary distal hub  625 . This causes the proximal tether memory metal strips  657  to reduce the height  661  of the distal basket at the proximal-most crown  638 , which in certain embodiments, allows the user to recapture the system  610  in the microcatheter  632 . This is particularly helpful if the system  610  was deployed at the wrong location. Preferably, the pull wire  643  includes a distal stop  660 , which prevents the proximal hub  39  from moving too far distally and breaking. 
       FIG. 46E  also exemplifies the proximal collapsed state. To move the basket  611  from the relaxed state to the proximal collapsed state, a user merely pulls the proximal hub  639  away from the stationary distal hub  625 . This causes the proximal tether memory metal strips  657  to reduce the height  661  of the distal basket at the proximal-most crown  638 , which in certain embodiments, allows the user to recapture the system  610  in the microcatheter  632 . This is particularly helpful if the system  610  was deployed at the wrong location. Preferably, the pull wire  643  includes a middle stop  655 , which prevents the proximal hub  639  from moving too far proximally. 
       FIG. 47  illustrates use of the basket system shown in  FIG. 46  in an intracranial artery  688 . As shown in  FIG. 47A , first the guide catheter  630  is deployed proximal to the clot  617 . The microcatheter  632  is then advanced distally beyond the clot  617 . The basket  611  is collapsed inside the microcatheter  632 . Next, as shown in  FIG. 47B , the microcatheter  632  is moved proximally to deploy the basket  611  distal to the clot  617 . The basket  611  is now in the relaxed state. Next, as shown in  FIG. 47C , the user continues to move the microcatheter  632  proximally. Then, as shown in  FIG. 47D , the basket  611  is moved closer to the clot  617  by a user pulling the pull wire  643  and coaxial tube  618  proximally at the same time. Then, as shown in  FIG. 47E , the user uses the coaxial tube  618  to move the proximal hub  639  toward the distal hub  625  so that the basket  611  is in the gaping state. The gaping state is particularly important, as it believed to allow the basket  611  to capture the clot  617  without having the clot  617  collapse the basket  611 . Then, as shown in  FIG. 47F , the basket  611  is moved proximally over the clot  617 . Then, as shown in  FIG. 47G , the coaxial tube  618  is moved further proximally to close the proximal end  669  around the clot  617 . The system  611  is moved proximally by moving the pull wire  643  and the coaxial tube  618  proximally simultaneously. 
       FIG. 50A  shows a close-up view of the proximal end of the basket  611 , including the proximal tube interior  641 , the attachment of the proximal tether memory metal strips  657  at the distal end  655  of the proximal hub  639 , and the proximal crowns  638  of the proximal cells  636 . In  FIG. 50A , all proximal crowns  638  of the proximal cells  636  are attached to a proximal tether memory metal strip  657 .  FIG. 50B  illustrates an alternative embodiment in which two proximal crowns  638   a  of a proximal cell  636  (the top and bottom crowns  638   a ) are attached to a proximal tether memory metal strip  657  and one proximal crown  638   b  of a proximal cell  636  is not attached to a proximal tether memory metal strip  657 .  FIGS. 50C-50E  illustrate that the basket system may include, for example, between 2 and 4 proximal tether memory metal strips  657 . 
       FIG. 56  illustrates a side, perspective view of a basket system  610  with relatively thick and short proximal tether memory metal strips  657  (i.e., the proximal tether memory metal strips  657  are slightly thicker than the memory metal strips  666  making up the proximal cells  636 . 
     In,  FIG. 57  the proximal tether memory metal strips  657  are thicker than the memory metal strips  666  forming the proximal cells  636  of the distal basket  611 . In these embodiments with thicker proximal tether memory metal strips  657 , the proximal tether memory metal strips  657  resist deforming when the proximal hub  635  is translated distally toward the stationary distal hub  629  and instead the proximal tether memory metal strips  657  are bowed out laterally, dissecting through or around the clot  617  and centering, buttressing and strengthening the opening of the basket  611 . In particular, as illustrated in  FIG. 57A , the basket  611  is deployed distal to the clot  617 . The basket  611  is move distally so that the clot  617  partially collapses the proximal tether memory metal strips  657 . See  FIG. 57B . The proximal hub  614 C is moved distally to slice the proximal tether memory metal strips  657  through the clot  617 . See  FIG. 57C . The basket  611  is moved proximally to ensnare the clot  617 . See  FIG. 57 . The tether proximal memory metal strips  657  are partially withdrawn into the microcatheter  632  and the system is removed from the body. See  FIG. 57E . 
       FIG. 51  illustrates a similar to basket system  610  to  FIGS. 46, 47 and 50 . In  FIG. 51 , the proximal tether memory metal strips  657  are relatively thin and short and the proximal memory metal strips making up the remainder of the basket are thickest at the proximal-most crown  38  and decrease gradually along the distal basket length  667 . 
       FIG. 52  illustrates a similar to basket system  610  to  FIGS. 46, 47, 50, and 51 . Again, the proximal tether memory metal strips  657  are relatively thin and short. In this embodiment, the length  654 A of the first proximal memory metal strip  657 A and the length  654 B of the second proximal memory metal strip  657 B are equal to the height  661  of the basket  611  in the relaxed state, as measured at the proximal-most crown  638 , plus or minus two mm. Thus, if for example, the height of the vessel  688  is 4 mm and the length of the proximal tether memory metal strips is 3 mm, the height  661  of the basket  611  as measured at the proximal-most crown  638  could be 4 mm. This is believed to allow the basket  611  in the gaping state to fill the vessel  688 . 
       FIG. 48  illustrates another embodiment of the basket system  610 . In this embodiment, the pull wire  643  does not extend through the entire basket  611  but rather ends at distal stop  660 . As compared to the embodiment of  FIGS. 46, 47 and 50 , the proximal tether memory metal strips  657  of the embodiment of  FIG. 48  are about the same thickness as the thickness  656  of the proximal cell memory metal strips  666 , which makes the basket  611  relatively rigid and the proximal tether memory metal strips  657  relatively inflexible, which may be desired for certain applications. As shown, moving the basket  611  from the relaxed state (see  FIG. 48A ) to the gaping state by moving the coaxial tube  618  proximally does not greatly enhance the basket height  661  in this embodiment due to the rigidity. 
       FIGS. 49A-49C  illustrate stepwise deployment and use of a basket system  610  with three relatively thin and short proximal tether memory metal strips  657 ; the system  610  is deployed in a blood vessel  688  to retrieve a clot  617 . 
       FIG. 53  illustrates another embodiment of the basket system  610 . In this embodiment, the proximal tether memory metal strips  657  are relatively thin (like the embodiment of  FIGS. 46, 47 and 50 ) but longer than the  FIGS. 46, 47, and 50  prior embodiment. This length allows the basket  611  to open asymmetrically around the clot  617  (see  FIG. 53C ), which is helpful if the microcatheter  632  and pull wire  643  are pushed against the vessel  688  wall by the clot  617 . As shown in  FIG. 53B , the length  654 A of the first proximal tether memory metal strip  657 A also may be two times the height  661  of the basket  611 , as measured at the proximal-most crown  638  plus or minus 2 mm and the length  654 B of the second proximal tether memory metal strip  657 B may be two times the height  661  of the basket  611  plus or minus 2 mm. Thus, for example, if the vessel  688  has a height of 4 mm and the length  654 A and  654 B of the proximal tether memory metal strips  657 A and  657 B are 7 mm each, the height  661  of the distal basket  611  as measured at the proximal-most crown may be set to for example 4 mm in the relaxed state. 
     It will be noted that the proximal end of the system  610  is shown at the bottom end of  FIGS. 45-62  and the distal end of the system  610  is shown at the top end of  FIGS. 45-62  because a principal use of the system  610  is to remove a blood clot  617  from a human intracranial artery  688 , in which case the system  610  generally will enter the artery  688  at its proximal end by the surgeon entering the patient&#39;s body near the groin and pushing the catheter  632  towards the brain. The diameter of human arteries  688  generally decrease from their proximal end to their distal end. However, when used in other types of lumens, the distal basket  611  may be located proximally relative to the catheter  632  as the term proximally and distally are used in that lumen. 
       FIG. 54  illustrates another embodiment of a basket system  611 . In this embodiment, the system  611  includes a proximal hub  639  that is slideable towards a distal hub  625  (similar to the prior embodiments). The difference is that the tether memory metal strips  657  actually join the proximal basket  633  and the distal basket  611 . More particularly, the proximal basket  633  is comprised of a plurality of proximal cells  636  attached to the proximal hub  639  and a plurality of distal cells  622  and the distal basket is comprised of a plurality of proximal cells  636  attached to the proximal hub  639  and a plurality of distal cells  622  and the tether memory metal strips  657  join a distal crown  623  of a distal cell  622  of the distal basket  611  with a proximal crown  638  of a proximal cell  636  of the proximal basket  633 . As shown, in  FIG. 54B , movement of the proximal hub  639  toward the distal hub  625  increases the height  634  of the proximal basket  633  as measured at the distal-most crown  623  of the distal basket  611 . 
       FIGS. 55  A and  55 B illustrate an embodiment of the proximal tether memory metal strips  657  rotating about said pull wire longitudinal axis  646  such that the distal end  653  of a proximal tether memory metal strip  657  is located between about 90 and about 270 degrees relative to said proximal end  655  of the same proximal tether memory metal strip  657 . In addition, the proximal tether memory metal strips  657  may rotate around their longitudinal axis  654  such that a distal end  653  of a proximal tether memory metal strip  657  rotates about 90 and about 270 degrees around this tether longitudinal axis  654  from the distal end  653  to the proximal end  655  of the same proximal memory metal strip  657 .  FIG. 55C  illustrates an exemplary embodiment, where the proximal end  655 A of the first proximal tether memory metal strip  657 A is located attached to the proximal tube  639  at the 12 o&#39;clock position and the distal end  653 A of the same proximal tether memory metal strip  657 A is attached to a proximal-most crown  639  at the 9 o&#39;clock position. In addition, the second proximal tether memory metal strip  657 B is located attached to the proximal tube  639  at the 6 o&#39;clock position and the distal end  653 B of the same proximal tether memory metal strip  657   b  is attached to the other proximal-most crown  639  at the 3 o&#39;clock position.  FIGS. 55D and 55E  illustrate a similar embodiment with the proximal tether memory metal strips  657 A and  657 B rotating 180 degrees.  FIG. 55D  illustrates an exemplary embodiment, where the proximal end  655 A of the first proximal tether memory metal strip  657 A is located attached to the proximal tube  639  at the 12 o&#39;clock position and the distal end  653 A of the same proximal tether memory metal strip  657 A is attached to a proximal-most crown  639  at the 6 o&#39;clock position. In addition, the second proximal tether memory metal strip  657 B is located attached to the proximal tube  639  at the 6 o&#39;clock position and the distal end  653 B of the same proximal tether memory metal strip  657   b  is attached to the other proximal-most crown  639  at the 12 o&#39;clock position. 
     In some embodiments, the basket system  610  is prepared by a process that includes one or more of the following steps, as illustrated in  FIG. 45 : 
     a) providing a single tube  668  comprised of a memory metal such as nitinol, the single tube  668  having an exterior, a substantially hollow interior, a wall  682  separating the exterior from the substantially hollow interior, an open proximal end  674 , an open distal end  676 , a middle portion  678  between the open proximal end  674  and the open distal end  676  (see  FIG. 45A ); 
     b) cutting the wall of the middle portion  678  with a laser  680  (see  FIG. 45B ); 
     c) removing the pieces of the middle portion cut by the laser  680  to form a basket system  610  comprising a proximal tube  639  comprising a hollow interior  641  extending through said proximal tube  639 , said proximal tube having a proximal end  642  and a distal end  640 , a distal tube  625  comprising a hollow interior  641  extending through said distal tube  625 , and a middle portion  678  located between said proximal tube  639  and said distal tube  625  and comprising a plurality of proximal tether memory metal strips  657 , each proximal tether memory metal strip  657  having a proximal end  655  attached to the distal end  640  of the proximal tube  639  and a distal end  653 ; 
     d) altering the shape of the middle portion  678  using a mandrel and allowing the middle portion  678  to expand relative to the distal tube  676  and proximal tube  674  to form a basket that includes cells  623  and  636 ; 
     e) quenching the middle portion  678  at room temperature; 
     f) removing the mandrel from the middle portion  678 ; 
     g) mechanically or chemically electropolishing the middle portion  678  to remove oxides (see  FIG. 45C ); 
     h) inserting a pull wire  643  through said proximal tube interior  641  so that said proximal tube  639  is slideable along at least a portion of said pull wire  643 , said pull wire  643  having a proximal end  645  and a distal end  644 ; and 
     i) attaching said pull wire  643  to said distal tube  625  so that the distal tube  625  is not slideable along the pull wire  643  but instead the distal tube  625  moves with the pull wire  643  (see  FIG. 45D ). 
     In other embodiments, steps h) and i) above replaced with the steps of inserting a pull wire comprising a proximal end, a distal end, a stop located adjacent to said distal end, through said proximal tube interior, said stop having a width and/or height that is greater than said proximal tube interior, said stop located distal relative to said proximal tube interior, so that said proximal tube is slideable distally until the proximal hub reaches said stop, said pull wire not contacting said distal tube; and attaching a leader wire to said distal tube. 
     In some embodiments, the middle portion  678  is expanded by heating the mandrel and the middle portion  678  by, for example, placing the mandrel and the middle portion  678  in a fluidized sand bath at about 500° C. for about 3 to about 7 minutes. As the middle portion  678  is heated, the heating causes the crystalline structure of the memory metal tube  668  to realign. Preferably, the mandrel is tapered (e.g., substantially conical or bullet in shape) so that the portion of the distal basket  611  formed from the middle portion  678  tapers from the proximal-most crown  638  to the distal end  666 . Preferably, the proximal and distal ends of the tube  674  and  676  are not shape set by the mandrel and are not cut by the laser  680  so that the proximal and distal ends  674  and  676  do not change in shape and only slightly expand in size under heating and return to the size of the native tube  668  after the heat is removed. Preferably, the laser cuts are programmed via a computer. To ensure that the laser cuts only one surface of the tube wall at the time (and not the surface directly opposite the desired cutting surface), the laser  680  is preferably focused between the inner and outer diameter of the desired cutting surface and a coolant is passed through the memory metal tube  668  so that the laser  680  cools before reaching the surface directly opposite the desired cutting surface. 
     The portions of the wall not cut by the laser  680  create the proximal and distal tubes  674  and  676  as well as the other components of the distal basket  611 , and memory metal strips  657  and  666 , as described. 
     Preferably, the memory metal selected for the native tube  668  has a heat of transformation below average human body temperature (37° C.) so that the distal basket  611  has sufficient spring and flexibility after deployment from the catheter  632  in the human blood vessel  688 . 
     In some embodiments, the native tube  668  (and hence the distal and proximal tubes  674  and  676 ) have an outer diameter of less than about 4 French, e.g., a diameter of about 1 to about 4 French. In some embodiments, the diameter of the pull wire  643  is between about 0.008 inches and about 0.051, as noted above, and in such embodiments, the diameter of the pull wire  43  may be approximately equal to the inner diameter  672  of the native nitinol tube  668 . 
     Without being bound by any particular theory, it is believed that manufacturing the distal basket  611  from a single memory metal tube  668  provides ease of manufacturing and safety from mechanical failure and provides tensile strength necessary for the system  610  to remove hard thrombus  617  and other obstructions. 
     In some embodiments, the method further includes providing a coaxial tube  618 , said coaxial tube  618  comprising a hollow interior  620  receiving said pull wire  643 , a proximal end  621 , and a distal end  619 , and attaching said distal end  619  of said coaxial tube  643  to said proximal tube  625 . In some embodiments, the method of attaching said distal end  619  of said coaxial tube  618  to said proximal tube  625  comprises welding said distal end  619  of said coaxial tube  618  to said proximal tube  625 . In other embodiments, the method of attaching said distal end  619  of said coaxial tube  618  to said proximal tube  625  comprises shrink wrapping said distal end  619  of said coaxial tube  618  to said proximal tube  625 . In other embodiments, the method of attaching said distal end  619  of said coaxial tube  618  to said proximal tube  625  comprises gluing said distal end  619  of said coaxial tube  618  to said proximal tube  625 . 
     Optionally, after step e, the basket  611  further comprises a row  648  of proximal cells  636 , each proximal cell  636  defined by a plurality of memory metal strips  666  and comprising a proximal crown  638  located at a proximal end of the cell  636  and pointing in the proximal direction and a distal crown  624  located at a distal end of the cell and pointing in the distal direction and further wherein each of said proximal crowns  638  of said proximal cells  636  is attached to a distal end  653  of a proximal tether memory metal strip  657 . Optionally, after step e, the basket  610  further comprises a row  647  of distal cells  622  located distal to said proximal cells  636  and connected to said distal crowns  624  of said proximal cells  636 , each distal cell  622  defined by a plurality of memory metal strips  666  and comprising a proximal crown  637  located at a proximal end of the cell  622  and pointing in the proximal direction and a distal crown  623  located at a distal end of the cell  622  and pointing in the distal direction, and further wherein the number of distal cells  622  is twice the number of proximal cells  636 . Optionally, after step e, the basket system  610  further comprises a row  649  of strut memory metal strips  652 , each strut memory metal strip  652  having a proximal end  651  attached to a distal crown  624  of a proximal cell  636  and a distal end  650  attached to a proximal crown  637  of a distal cell  622 . Optionally, the basket  611  comprises no welded components and said proximal tether memory metal strips  657  are integral with said proximal cell crowns  638 . 
     Optionally, after step e, the basket system  611  comprises between two and four proximal tether memory metal strips  657 . Optionally, prior to cutting the memory metal tube  668 , the memory metal tub  668  has an outer diameter  686  that is from about 0.011 inches to about 0.054 inches and an inner diameter  684  that is from about 0.008 inches to about 0.051 inches. Optionally, after step e), the proximal tube  639  and distal tube  625  have an outer diameter that is from about 0.02 inches to about 0.03 inches and an inner diameter that is from about 0.01 inches to about 0.02 inches. Optionally, the method further includes placing said basket  611  inside a catheter  632  comprised of a biocompatible material. Optionally, the method further includes the steps of placing the basket  611  inside a lumen  688  of an animal and using the basket to retrieve an object  617  located inside said lumen  688 . 
     In other embodiments, as shown in  FIGS. 58-60 , the basket system  610  does not include a proximal hub  639  and the system  610  includes a plurality of cords  703  (e.g., 2-4 cords  703 ) instead of or in addition to said proximal tether memory metal strips  657 . For example,  FIG. 15-17  shows a first set of embodiments, where soft cords made of rubber, nylon, suture material, braided catheter material, platinum coils, and ultrathin nitinol for example, are used. The cords  703  have a proximal end  704  attached to the distal end  619  of the coaxial tube  618  and a distal end  705  attached to a proximal crown  638  of a proximal cell  636 .  FIG. 58  illustrates one embodiment in which the cords  703  are relatively long.  FIG. 59  illustrates another embodiment in which the cords  703  are relatively short. 
     In some embodiments, the system  610  is used in a method that includes 
     a) providing the system  610 ;
 
b) positioning the system  610  in said lumen  688 , said basket  611  located in said catheter  632  in a collapsed state (see  FIG. 60A );
 
c) deploying said distal basket  611  from said distal end  614  of said catheter  632  so that said proximal crowns  638  of said proximal cells  636  are distal to said obstruction  617 ;
 
d) allowing said distal basket  611  to move to said relaxed state (see  FIG. 60B );
 
e) moving said coaxial tube  618  distally relative to said distal hub  625  so that said coaxial tube  618  moves distally to the proximal-most crown  638  (see  FIG. 60C );
 
f) moving said distal basket  611 , said pull wire  643  and said coaxial tube  618  proximally simultaneously so that said distal basket  611  moves over said obstruction  617  (see  FIG. 60D );
 
g) moving said coaxial sheath  618  distally relative to said distal hub  625  so that said distal basket height  661 , as measured at the proximal-most crown  638 , decreases and said coaxial tube  618  is closer to said distal hub  625  as compared to the proximal-most crown  638  (see  FIG. 60E ); and
 
h) removing said distal basket  611  and said obstruction  617  from said lumen  688  (see  FIG. 60F ).
 
     In other embodiments, steps g-h above are replaced with the steps below: 
     g) moving said coaxial sheath  618  proximally relative to said distal hub  625  so that said distal basket height  661 , as measured at the proximal-most crown  661 , decreases;
 
h) moving said catheter  632  distally relative to said distal hub  625  so that said catheter  632  re-sheaths said coaxial sheath  618  and partially re-sheaths said cords, thereby decreasing said distal basket height  661 , as measured at the proximal-most crown  638 ;
 
i) removing said distal basket  611  and said obstruction  617  from said lumen  688 .
 
     As shown, an advantage of this embodiment is that the cords  703  move distally to the proximal-most crowns  638  so they do not obstruct entry way of the clot  617  into the distal basket  611 . 
     In other embodiments, as shown in  FIGS. 61 and 62 , the system  610  includes cords  703  and proximal tether memory metal strips  657 . In such embodiments, the proximal tether memory metal strips  657  have a proximal end  655  attached to the distal end  619  of the coaxial tube  618 . The cords have a proximal end attached to the distal end  653  of the proximal memory metal strips  657  and a distal end attached to a proximal crown  638  of a proximal cell  636 . 
     In some embodiments, the system  610  is used in a method of removing an object from an interior lumen  688  of an animal, said lumen  688  having an interior wall forming said lumen  688  that includes: 
     a) providing the system  610 ; 
     b) positioning the system  610  in said lumen  688 , said basket  611  located in said catheter  632  in a collapsed state; 
     c) deploying said distal basket  611  from said distal end  614  of said catheter  632  so that said proximal crowns  638  of said proximal cells  636  are distal to said obstruction  617 , said coaxial sheath  618  is proximal to said obstruction  617 , said proximal tether memory metal strips  657  are proximal to said obstruction  617 , and said cords are adjacent to said obstruction  617 ; 
     d) allowing said distal basket  611  to move to said relaxed state (see  FIG. 62A ); 
     e) moving said coaxial tube  618  distally relative to said distal hub  625  and moving said basket  611  proximally so that said proximal tether memory metal strips  657  move distally relative to the proximal-most crown  638  and said obstruction  617  is sandwiched between said proximal tether memory metal strips  657  and said proximal crowns  638  of said proximal cells  636  (see  FIG. 62B ); and 
     f) removing said distal basket  611  and said obstruction  617  from said lumen  688 . 
     Having now described the invention in accordance with the requirements of the patent statutes, those skilled in the art will understand how to make changes and modifications to the disclosed embodiments to meet their specific requirements or conditions. Changes and modifications may be made without departing from the scope and spirit of the invention, as defined and limited solely by the following claims. In particular, although the system has been exemplified for use in retrieving blood clots, the system may be used to retrieve other objects from animal lumens. In addition, the steps of any method described herein may be performed in any suitable order and steps may be performed simultaneously if needed. 
     Terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.