Abstract:
An endoscopic surgical device for retrieving objects, such as for example, severed human tissue, foreign objects or impacted food bolus, from within a subject is disclosed. The device includes a body and handle movable relative to the body, a tubular member fixed to the body, a link having a first end fixed to the handle and a second end remote from the body, and a net including a loop and a net element. The loop is expandable and collapsible by action of the handle relative to the body. The loop retains an expanded configuration when deployed to allow for the capture certain objects that were otherwise difficult to capture because of positioning, location, or object characteristics. The loop may be constructed of flat wire and form a polygon shape when deployed. Structure at the distal end of the loop may propel and retain the loop into an open position when in use in narrow organs such as the esophagus.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application claims the benefit of U.S. Provisional Patent Application No. 60/574,072, entitled “Retrieval Device,” filed May 25, 2004, which is hereby incorporated in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a retrieval device and more particularly to a endoscopic retrieval device for retrieving objects from within a human subject. 
     BACKGROUND OF THE INVENTION 
     Endoscopic retrieval or removal devices are known in the art and are conventionally used to recover objects from inside a human subject. Such objects may include severed human tissue, foreign objects, or food bolus. Some typical devices include forceps or clasps to grab objects. Certain devices of this type are not well-suited for retrieving rounded or blunt foreign objects such as coins, marbles and batteries because they are difficult to hold secure. Further, if a foreign object is dropped near the trachea during the removal process the results can be catastrophic for the patient. 
     Devices using netting have been developed to capture rounded or blunt objects. U.S. Pat. No. 6,814,739 to Secrest et al., which is incorporated herein by reference in its entirety, discloses a device for retrieving an object from within a subject. In the use of devices having netting, and it is believed in the use of other devices, physicians have experienced difficulty in recovering certain objects, such as for example, impacted food bolus from the esophagus. A bolus is a mass of masticated or chewed food. In some cases, the bolus becomes impacted in the esophagus due to disease states, and other disorders and consequently, does not pass into the stomach. An object of this type may be more difficult to position over or be more heavier than the human tissue or foreign object for which these type of devices were designed. This problem is especially apparent when working in relatively tight places within the body. As a result, netting support collapses and does not retain its shape in a deployed position when holding the captured object. 
     To solve these and other problems, the present invention uses a flat wire to make the loop that supports the retrieval net. The flat wire provides a wider net capacity to entrap the bolus and is firmer, more rigid and less likely to collapse. As such, the loop maintains its shape in use, particularly when used in narrow lumens like the esophagus. The flat wire can be formed into a polygon shape, is more likely to be resistant to collapse and can include distal tip structure designed to further resist collapse and promote expansion. 
     SUMMARY OF THE INVENTION 
     In an illustrated embodiment of the invention, a device for retrieving objects, such as for example, impacted food bolus, foreign objects, and severed human tissue, is disclosed. The device is for use within an instrument channel of an endoscope during endoscopic medical procedures. 
     The device includes a body, a handle fixed to and movable relative to the body, an elongated tube fixed to the body, a link extending substantially through the tube and having a first end fixed to the handle and a second end remote from the body, and a net including a loop and a net element. The loop is expandable and collapsible by action of the handle relative to the body. 
     The loop retains an expanded configuration when deployed, allowing for relatively heavy objects to be disposed within the net element. The loop may be constructed from, for example, a stainless steel flat wire or other suitable material having a tensile strength greater than 300,000 psi. 
     The present invention is an improvement over prior art designs because the loop supporting the net is less likely to collapse under the weight of an object such as an impacted food bolus. Moreover, the wire opens wider than prior art designs when used in narrow lumens like the esophagus. The device allows for the capture of relatively heavy objects and reduces the risk associated with the procedure. Once an object is secured within the net element, the wire loop advantageously resists collapse. 
     Further features and advantages of the invention will become apparent from the following detailed description made with reference to the accompanying drawings. 
     The Detailed Description of the Invention merely describes preferred embodiments of the invention and is not intended to limit the scope of the claims in any way. Indeed, the invention as described by the claims is broader than and unlimited by the preferred embodiments, and the terms in the claims have their full ordinary meaning. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a retrieval device constructed in accordance with an embodiment of the present invention; 
         FIG. 2  is a cross-sectional fragmentary view of the distal portion of the device illustrated in  FIG. 1 , showing a net in a stored position within a tube; 
         FIG. 3  is an alternative view of the portion illustrated in  FIG. 2 , showing the net in a deployed position outside of the tube; 
         FIG. 4  is an exploded perspective view of the designated circular section of  FIG. 1 , showing detail of the net element and the distal end of the loop; 
         FIG. 5  is a exploded fragmentary top view of the net of a retrieval device, showing an alternative structure of the distal end of the loop; 
         FIG. 6  is a exploded fragmentary top view of the net of a retrieval device, showing yet another alternative structure of the distal end of the loop; and 
         FIG. 7  is a perspective view of a distal portion of the device illustrated in  FIG. 4 , showing a food bolus captured within the net. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     A device for retrieving an object from within a human subject is disclosed. The device is designed for use within an endoscope and may be used for retrieving relatively heavy objects within relatively tight lumens, such as for example, impacted food bolus from the esophagus. In discussing the device, the terms distal and proximal are used with respect to the operator&#39;s hand. In other words, when the device is used within the auxiliary channel of an endoscope or similar device, the proximal and distal orientation are relative to the surgeon or operator of the device. 
     Referring now to the drawings,  FIG. 1  is a perspective view of a retrieval device  10  constructed in accordance with an embodiment of the present invention. The device includes a support base or elongated body  14 . The body includes a ring  16  at a proximal end. The device  10  also includes a handle  18  having two rings  20 . The handle  18  is mounted over an interior section  15  of the body  14  and is movable relative to the body in the direction A 1  as illustrated. For example, an operator may place a finger in each of the rings  20  and thumb of the same hand in the body ring  16 . By moving one&#39;s fingers in the direction A 1 , an operator can move the handle  18  relative to the body  14 . In contrast, the handle can be slid a direction opposite A 1  by pulling one&#39;s finger&#39;s towards one&#39;s thumb. 
     The device includes an elongated inducer member or tubular member  24  having a first end  26  fixed to the body  14  and a second end  28 . The tubular member  24  and the body are a fixed support assembly for the moving parts of the device. The tubular member  24  may be any suitable small diameter tube formed of a non-reactive low-friction plastic material, such as for example, polytetrafluouroethylene. The tubular member  24  defines a passage with an opening  30  at the tubular member second end  28 , as best seen in  FIG. 2  which shows cross-sectional view of a distal portion of the device  10 . 
     A motion transmitting link  34  is connected to the handle  18 . The link  34  has a first end  36  fixed to the handle  18  and a second end  38  remote from the body  14 . As shown in the drawings, the link extends substantially through the tubular member  24  passage. The link may be constructed of any suitable rigid material. 
     Still referring to  FIG. 1 , the device also includes a net  50 . The net is used by the operator to capture and retrieve objects from within a human subject. The net  50  includes a loop  52  and a net element  54  secured to the loop  52 . The loop may be inserted through a mouth section of the net or otherwise connected in any conventional manner known in the art. As shown in several Figures, a net tether  57  at the distal end of the net anchors the net element  54  to the loop  52  at a distal end  53  of the loop. 
     As discussed, the net is designed for movement between two positions.  FIGS. 1 and 2  shows the net  50  in these two possible positions.  FIG. 1  shows the net  50  in a deployed position. In this position, the net has a length L 1  and a width W 1 . The ratio of L 1  and a width W 1  is less than prior art designs, meaning the device has increased width capacity.  FIG. 2  is a cross-sectional view of a distal portion of the device  10 , showing the net in a stored position within the tube  24 . In this position, the net has a length L 2  which is considerably longer than L 1 . As shown in  FIG. 2 , the net  50  is disposed adjacent the link  34  second end  38  for deployment and retrieval through the tubular member passage opening  30 . By movement of the handle  18  relative to the body  14 , the net is movable between either the deployed or stored positions. 
     Referring now to  FIG. 3 , the net  50  is illustrated in a deployed position and fully expanded outside of the tube  24  second end  28 . The net element  54  may be constructed of any suitable light weight material, such as for example, nylon mesh string  56 , as best seen in  FIG. 4 . The net element  54  has a centrally located object receiving pouch section  58 . To be discussed further in greater detail, captured objects rest within this section as shown in  FIG. 7 . 
     As discussed, the net  50  includes a loop  52 . The loop  52  acts as a support for the net  50  when deployed. The loop  52  is resiliently movable between a collapsed position shown in  FIG. 2  to an expanded position shown in  FIG. 3  by operator action of the handle relative to the body. A distal end  53  includes structure to resist collapse during use. 
     Referring now to  FIG. 4 , an exploded perspective view of the designated circular section of  FIG. 1  is shown. In the embodiment shown, the loop  52  is a flat wire constructed of a resilient material, such as for example, 304 stainless steel. The loop material may be constructed from a material having a tensile strength greater than 300,000 psi. 
     Referring again to  FIG. 3 , the loop  52  includes collapse-resistant bends  60 , with the straight segments between the bends  60  forming a polygon shape. As apparent from  FIG. 3 , a maximum width W 1  of the loop  52  is defined by two opposing linear segments of the polygon. As shown, the two opposing linear segments are also parallel. In regard to these two linear segments, the distance along a longitudinal axis of the loop  52  from a distal most point of each linear segment to a distal most point of the loop is less than the distance from a proximal most point of each linear segment to a proximal most point of the loop. In other words,  FIG. 3  illustrates a majority of each of the two opposing linear segments disposed closer to the distal end of the loop  52  as compared to the proximal end of the loop  52 . This positioning is apparent from their relative placement along the length L 1  of the loop  52 . 
     Other features of the invention are apparent from  FIG. 3 . As previously stated, the polygon shape of the support loop defines a pair of lengthwise extending parallel linear wire segments that define a maximum width W 1  of the support loop  52 . Additional linear wire segments which extend distally from an end of each of the parallel wire segments taper distally to connect with the spiral wire structure. Additional linear wire segments which extend proximally from an end of each of the parallel wire segments taper proximally to connect within the introducer passage opening. 
     The loop  52  is illustrated having a first and a second support loop portion in  FIG. 3 . The first support loop portion is “V” shaped and flares outwardly in a distal direction from the elongated hollow tube  24 , with a pair of lengthwise parallel wire segments at a widest portion W 1  of the “V” shape. The second support loop portion is “V” shaped and flares outwardly in a proximal direction from the spiral spring  64  to connect with a distal end of each parallel wire segment of the lengthwise parallel wire segments. The collapse resistant bends  60  and the linear wire segments located between the spiral spring and each of the parallel wire segments are oriented to “V” inward, as seen in  FIG. 4 , into the net. Also, the second support loop portion is shorter along a net length L 1  than the first support loop portion. 
     The illustrated device in  FIGS. 2 and 3  includes several features that promote expansion and prohibit collapse when an object is held within the net element or the device is used in a relatively tight lumen. The loop  52  includes several collapse-resistant bends  60 . The location of the bends  60  act as memory points and are retained by the loop through multiple deployments. These bends are constructed such that the loop forms a polygon shape when deployed. As shown, the loop  52  forms a general hexagon shape. It is believed that the polygon shape is more resilient and less likely to collapse when an object is held within the net or when retrieving an object within a narrow lumen. It should be understood by those with ordinary skill in the art that the polygon shape shown in  FIG. 3  is for exemplary purposes only, and other polygon shapes can be used in the practice of the present invention. 
     As best shown in  FIG. 4 , the loop  52  further includes a 360 degree curved portion  64  disposed at a distal end  53  of the loop. It is believed that this curved portion  64  acts as a spring tip to further prohibits collapse when an object is held within the net. It is also believed that this spring tip  64  acts to promotes polygon segments  65   a ,  65   b  to remain apart during deployment. This feature is beneficial in tight lumens, such as for example, the esophagus. 
     Several other embodiments include alternative shapes and structures of the distal end of the loop.  FIG. 5  shows the distal end of the support wire in an alternative shape. The loop  52  is bent to form a protruding tip  68 . It is believed that this shape promotes polygon segments  69   a ,  69   b  to remain apart during deployment and use. 
     Referring to  FIG. 6 , an exploded fragmentary view of other alternative structure of the distal end  53  of the loop  52  is shown. As in the embodiment shown in  FIG. 5 , the distal end of the loop  52  is bent into a protruding tip  68 . Over the spring tip  68 , a tip cap member  70  is press fit or connected by another suitable technique. The tip  70  may be constructed of plastic or any other suitable material. The tip  70  includes an aperture  72  therethrough as a distal end. As shown, the net anchor  57  is placed through the aperture and tied off to secure the net element  54  to the loop  52 . A corresponding anchor  59  can be used to tie off the net element  54  to the link  34  on the proximal side of the wire loop connector. 
     In an exemplary operation of the device, the patient is intubated with an endoscope. The device  10  is inserted through an auxiliary channel of the endoscope, either before or after intubation. The device is inserted with the net  50  in a stored position as shown in  FIG. 2 . The surgeon utilizing the optical features of the endoscope will identify the object for removal. After identification, the surgeon with manipulate the handle  18  with respect to the base  14  to deploy the net  50  into the position shown in  FIG. 1 . 
     The surgeon will manipulate the object into the receiving pouch  58  by one of a variety of techniques, including the use of additional endoscopic tools. The surgeon may manipulate the snare over the top of the object and enclose the net, or manipulate the snare under the object and enclose the net. Further, the surgeon may use the net as a scoop, relying on the increased lateral stability of the device over prior art designs. Once the object is within the pouch, the surgeon may manipulate the handle with respect to the body to slightly close the net around the object.  FIG. 7  is a perspective view of a distal portion of the device illustrated in  FIG. 4 , showing a food bolus captured within the net. In this position, the loop retains an expanded configuration with an object  80  retained within the pouch section  58 . The endoscope now may be removed from the patient with risk of loss of the food bolus greatly reduced as compared to prior art devices. 
     While several embodiments of the invention has been illustrated and described in considerable detail, the present invention is not to be considered limited to the precise construction disclosed. Various adaptations, modifications and uses of the invention may occur to those skilled in the arts to which the invention relates. It is the intention to cover all such adaptations, modifications and uses falling within the scope or spirit of the claims filed herewith.