Abstract:
Systems and methods are provided for delivering and mechanically detaching embolic coils. The systems disclosed herein comprise a mechanical detachment mechanism to intravascularly release an embolic coil. The methods disclosed herein comprise a various triggering mechanisms to detach embolic coils.

Description:
CROSS-REFERENCE 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/343,528, filed May 31, 2016, and U.S. Provisional Application No. 62/343,542, filed May 31, 2016, which are incorporated herein by reference in their entireties. 
     
    
     BACKGROUND 
       [0002]    A number of vascular disorders are treated by an intravascular delivery of an implant that is either positioned or deployed within a vessel of a body of an individual. For example, an intravascular stent used for treating peripheral artery disease may be deployed in a stenotic region of a blood vessel in order to improve blood flow past the stenosis in the vessel. For further example, an embolic coil may be placed or deployed within an intracerebral aneurysm in order to occlude the aneurysm thus preventing blood flow into the aneurysm and thus preventing a rupture of the aneurysm. 
       SUMMARY 
       [0003]    Described herein are systems and methods for delivering an intravascular implant. The systems and methods described herein use an intravascular approach for delivering an implant into the intravascular system of a patient. In some embodiments of the systems and methods described herein, the systems and methods comprise a mechanical detachment system that is configured to deploy an intravascular implant, such as an embolic coil, at a target location within the vascular system of a patient when a user manually deploys the implant. 
         [0004]    In some embodiments of the systems and methods described herein, the systems and methods are used for the delivery of an embolic coil to an intracranial aneurysm and are configured to provide manually triggered deployment of an embolic coil within the intracranial aneurysm. 
         [0005]    The systems and methods described herein improve upon traditional implant detachment systems, such as, for example, embolic coil detachment systems, in a number of ways: 
         [0006]    Prevention of Undesired Thrombotic Events 
         [0007]    One example of how the systems and methods described herein improve on traditional systems and methods for delivering embolic coils is by preventing undesired thrombotic events. 
         [0008]    Many traditional systems and methods for delivering embolic coils to cerebral aneurysms employ electrolytic detachment mechanisms, which have been shown to cause generation of gas bubbles at the detachment zone. The formation of gas bubbles intravascularly leads to the formation of blood clots, which may lead to thromboembolic complications. Furthermore, if the clot remains attached to a micro-catheter tip or to the end of an embolic coil, there is a risk that the clot will grow in size and/or embolize during repeated embolic coil detachment procedures. This presents an increased risk of the generation of blood clots which can travel to small vessels and occlude these vessels leading to anoxic injury. 
         [0009]    Decrease in Detachment Time 
         [0010]    Another example of how the systems and methods described herein improve on traditional systems and methods of delivering embolic coils is by decreasing the time to detach the total number of embolic coils. 
         [0011]    The systems and methods described herein take significantly less time to detach and deploy an embolic coil as compared to traditional electrolytic systems. The systems and methods described herein comprise mechanical components that actuate rapid deployment whereas electrolytic systems require time to heat an embolic coil system in order to detach and deploy a coil. As, in most cases, delivery of multiple embolic coils into one cerebral aneurysm is often necessary, the reduction in procedure time by the systems and methods described herein presents a significant advantage. 
         [0012]    Prevention of Detachment Failure 
         [0013]    Yet another example of how the systems and methods described herein improve on traditional systems and methods of delivering embolic coils is by preventing a failed detachment of an embolic coil. 
         [0014]    Traditional electrolytic detachment systems and methods have been shown to have a significant detachment failure rate. Detachment failure may occur due to electrical equipment failure and/or failure to properly induce a current through the device and the patient. Because the systems and methods described herein employ mechanical components rather than electrical components, the failure rate is significantly lower than that of the traditional electrolytic deployment systems. 
         [0015]    Described herein is an embolic coil delivery system for delivering and deploying an embolic coil at an aneurysm comprising:
       i. a conduit having a deployment location from which the embolic coil is deployed and a first radiopaque marker:   ii. a detachment system configured to fit within the conduit and to be slideably advanced and withdrawn within the conduit, the detachment system comprising:
           a. a detachment mechanism comprising:
               1) a tab comprising a memory material and having a first position and a second position, wherein the memory material is configured to move the tab from the first position to the second position;   2) a primary member configured and positioned to engage with the tab so that the tab is in the first position when engaged with the primary member and is moved to the second position by the memory material when the primary member is no longer engaged with the tab;   3) an anchoring element coupled to the embolic coil and configured and positioned to engage with the tab in the first position so that the embolic coil is coupled to the detachment system when the tab is in the first position, and wherein the anchoring mechanism is configured and positioned to not engage with the tab in the second position so that the embolic coil is deployed when the tab is in the second position;   4) a radiopaque marker coupler;   
               b. a second radiopaque marker that is mechanically coupled with the radiopaque marker coupler and is positioned to align with the first radiopaque marker when the detachment mechanism is positioned at the deployment location.   
               
 
         [0024]    In some embodiments of the delivery system, the detachment system comprises a flexible tube that surrounds the detachment system and fixedly couples the radiopaque marker coupler and the radiopaque marker. In some embodiments of the delivery system, the first radiopaque marker partially surrounds the conduit so that when the detachment mechanism is advanced within the conduit and the first radiopaque marker aligns with the second radiopaque marker, the second radiopaque marker is radiographically visible. In some embodiments of the delivery system, the tab comprises a memory metal material. In some embodiments of the delivery system, the detachment mechanism further comprises a primary member that detachably couples with the tab so that when the primary member and the tab are coupled, the tab is in the first position and when the primary member and the tab are decoupled, the tab moves to the second position. In some embodiments of the delivery system, the tab moves to the second position when the primary member is drawn away from the tab. In some embodiments of the delivery system, the detachment system includes a segment that is configured to manually detach from the detachment system, and wherein the primary member is coupled to the segment so that when the segment is manually detached and withdrawn away from the detachment system, the primary member is drawn away from the tab so that the tab moves to the second position and deploys the coil. In some embodiments of the delivery system, the segment comprises oblong cuts around its outer diameter that are configured to fracture the segment when a bending force is applied to the segment. In some embodiments of the delivery system, the primary member is coupled with a hand-held detachment device configured to clamp the primary member such that the primary member is drawn away from the tab when the grip is drawn away from the conduit, and wherein the grip comprises a viewing window that shows when the primary member is drawn away from the tab. 
         [0025]    Also described herein is a method for deploying an embolic coil in an intracranial aneurysm comprising: directing a conduit through one or more blood vessels of the patient to the aneurysm, the conduit comprising a first radiopaque marker and a deployment location; advancing a detachment system through the conduit while the conduit is within the blood vessel, the detachment system comprising a radiopaque marker coupler, a second radiopaque marker, and a detachment mechanism comprising a tab having a first position and a second position; deploying the embolic coil within the aneurysm using the detachment system; wherein the radiopaque marker coupler and the second radiopaque marker couple mechanically; wherein when the detachment mechanism is positioned at the deployment location, the first radiopaque marker and the second radiopaque marker align; wherein the embolic coil is coupled to an anchoring element; wherein when the tab is in the first position, the anchoring element engages the tab thus coupling the embolic coil to the detachment system; and wherein the anchoring element does not engage the tab in the second position thus decoupling the embolic coil from the detachment system and thus deploying the embolic coil in the intracranial aneurysm. In some embodiments of the method, the detachment system comprises a flexible tube that surrounds the detachment system and fixedly couples the radiopaque marker coupler and the radiopaque marker. In some embodiments of the method, the first radiopaque marker partially surrounds the conduit so that when the detachment system is advanced within the conduit and the first radiopaque marker aligns with the second radiopaque marker, the second radiopaque marker is radiographically visible. In some embodiments of the method, the tab comprises a memory metal material. In some embodiments of the method, the detachment mechanism further comprises a primary member that detachably couples with the tab so that when the primary member and the tab are coupled, the tab is in the first position, and when the primary member and the tab are decoupled, the tab moves to the second position. In some embodiments of the method, the step of deploying comprises decoupling the primary member from the tab by drawing the primary member away from the tab. In some embodiments of the method, the conduit includes a segment that is configured to manually detach from the conduit, and wherein the primary member is coupled to the segment so that when the segment is manually detached and withdrawn away from the conduit, the primary member is drawn away from the tab so that the tab moves to the second position and deploys the embolic coil. In some embodiments of the method, the segment comprises oblong cuts around its outer diameter that are configured to fracture the segment when a bending force is applied to the segment. In some embodiments of the method, the primary member is coupled with a hand-held detachment device configured to clamp the primary member such that the primary member is drawn away from the tab when the grip is drawn away from the conduit, and wherein the grip comprises a viewing window that shows when the primary member is drawn away from the tab. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    The novel features of the subject matter disclosed herein are set forth with particularity in the appended claims. A better understanding of the features and advantages of the subject matter disclosed herein will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the subject matter disclosed herein are utilized, and the accompanying drawings of which: 
           [0027]      FIG. 1  shows an illustration of the anatomical path of travel of a delivery system. 
           [0028]      FIG. 2  shows an illustration of an exemplary embodiment of a delivery system for delivering and deploying an intravascular implant such as an embolic coil. 
           [0029]      FIG. 3  shows an illustration of an exemplary embodiment of a detachment system which comprises an embolic coil that is detachably coupled to the detachment system. 
           [0030]      FIG. 4  shows an illustration of an embodiment of a distal end of a detachment system as an embolic coil is deployed from a detachment system. 
           [0031]      FIG. 5  shows an exemplary illustration of an embodiment of an expansion tube. 
           [0032]      FIGS. 6A-6B  show an illustration of a mechanism for manually deploying an intravascular implant using a hand-held detachment device. 
           [0033]      FIG. 7  shows an illustration of a close-up view of a cross-section of the hand-held detachment device which shows clamping cams griping a grip tube of the detachment system. 
           [0034]      FIGS. 8A-8B  show illustrations of what a user sees in a viewing window, wherein the viewing window is a feature of some embodiments of the hand-held detachment device as described. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    Described herein are systems and methods for delivering and deploying an intravascular implant to an intravascular target such as, for example, delivering one or more embolic coils to an intracranial aneurysm and deploying the one or more embolic coils within the aneurysm. 
         [0036]    A delivery system as described herein comprises a conduit such as a traditional catheter or micro-catheter and a detachment system that is configured to be slideably advanced within the catheter. The catheter of the delivery system described herein is configured to be advanced through a blood vessel of a patient to a target location. For example,  FIG. 1  shows an illustration of the anatomical path of travel of a catheter  1014 . The catheter  1014  may be inserted into a femoral artery of a patient (using, for example, Seldinger technique) and advanced up through the aorta  1050  of the patient, from there the catheter may be advanced up through a carotid artery  1060  to an intracranial target location such as an intracranial aneurysm where an intravascular implant may be deployed in order to, for example, occlude the aneurysm thus preventing aneurysm rupture. The conduit of the delivery system is thus configured to deliver the detachment system described herein to a target location. In some embodiments, the delivery system as described herein does not include a conduit, but rather the detachment system is delivered directly to a target location. 
         [0037]    Delivery System 
         [0038]      FIG. 2  shows an illustration of an exemplary embodiment of a delivery system  2000  for delivering and deploying an intravascular implant (not shown) such as an embolic coil. Other non-limiting examples of implants suitable for use with the systems, devices, and methods described herein include, for example, occluding coils and intravascular stents. 
         [0039]    A delivery system  2000  comprises a conduit such as a standard catheter  2014  or micro-catheter (or other conduit) and a detachment system  2004 . In the exemplary embodiment shown in  FIG. 2 , the conduit of the delivery system  2000  comprises a catheter  2014 . The detachment system  2004  comprises an elongate body that is configured to be slideably positioned (i.e. advanced and withdrawn) within the catheter  2014  and, in some embodiments, the detachment system  2004  is delivered via the catheter  2014  to a target location such as, for example, an intracranial aneurysm. That is, in embodiments of the delivery system that include a catheter  2014 , the catheter  2014  with the detachment system  2004  within it is typically delivered to a target location by a user, wherein a target location may comprise, for example, an intracranial aneurysm or, for example, an atherosclerotic lesion. In other embodiments, the detachment system  2004  is delivered directly to a target location. 
         [0040]    Detachment System 
         [0041]    The detachment system  2004  comprises a proximal end  2017  and a distal end  2016 , which are each configured to include different functional elements of the detachment system  2004 . In general, the proximal end  2017  of the detachment system  2004  remains outside of the patient during the use of the delivery system  2000 , and the proximal end  2017  of the detachment system  2004  generally includes features that allow a user to manually direct the detachment system  2004  and control the deployment of an implant. The proximal end  2017  of the detachment system  2004  is configured to provide a mechanism for manually deploying an implant at a target location by a user of the delivery system  2000 . In general, the distal end  2016  includes a detachment mechanism  2005  that is configured to release or deploy an intravascular implant at a target location and a radiopaque marker  2006  that is positioned to align with a radiopaque marker on the distal end of the catheter  2014  when the detachment system  2004  is within a proper position relative to the catheter  2014  for implant deployment. 
         [0042]    Detachment system  2004  comprises a detachment mechanism  2005  at its distal end  2016 . In some embodiments of the delivery system  2000 , the detachment system  2004  comprises a detachment mechanism and forms an elongate body comprising a series of respectively optional interconnected tubes comprising an optional shrink tube  2002 , an optional connecting tube  2010 , an optional expansion tube  2026 , and an optional grip tube  2012 . The optional interconnected tubes  2002 ,  2010 , and  2026 , and  2012  are each respectively configured to provide different qualities or features to the detachment system  2004 . A shrink tube  2002  comprises a flexible material such as a polymer, and is configured to cover and/or surround at least a portion of the distal end  2016  of the detachment system  2000  while providing flexibility to maneuver through bends in the vasculature system. The shrink tube  2002  also maintains a tight coupling between the radiopaque marker  2006  and the detachment mechanism  2005  via mechanical coupling between the radiopaque marker  2006  and a radiopaque marker coupler  2008 . A connecting tube  2010  may optionally be connected to the shrink tube  2002  and comprises a relatively rigid material (as compared to the shrink tube  2002 ) that provides rigidity to portions of the distal  2016  end and/or proximal end  2017  so that the detachment system  2004  is more easily advanced and withdrawn within the catheter  2014 . An expansion tube  2026  is optionally connected to the connecting tube  2010 , and provides a segment with an expanded diameter (as compared to the optional shrink tube  2002  and connecting tube  2010 ) providing ease of handling relative to the relatively small diameter optional shrink tube  2002  and connecting tube  2010 . In some embodiments of the detachment system  2004 , and expansion tube  2026  facilitates deployment of an implant from the detachment mechanism  2005  by facilitating manual withdrawal of a primary member  2018 . An optional grip tube  2012  provides a hand grip for a user, and in some embodiments of the detachment system  2004  it is replaced by a hand-held detachment device. A connecting wire  2011  connects the distal portion of the detachment system. 
         [0043]    In some embodiments of the delivery system  2000 , a detachment mechanism  2005  entirely comprises a memory metal material such as, for example, nitinol. In some embodiments of the detachments system  2004 , only the detachment mechanism  2005  comprises a memory metal material such as nitinol. In some embodiments of the detachment mechanism  2005 , the detachment mechanism  2005 , not including the primary member  2018  (which comprises a different material), comprises a memory material such as nitinol. In some embodiments of the detachment mechanism  2005 , the detachment mechanism  2005 , not including the radiopaque marker  2006  (which comprises a different material), comprises a memory material such as nitinol. In some embodiments of the detachment mechanism  2005 , the detachment mechanism  2005 , not including the primary member  2018  and the radiopaque marker  2006  (which comprise a different material), comprises a memory material such as nitinol. 
         [0044]    The distal end of the detachment system  2004  includes a radiopaque marker  2008 , and the distal end of the catheter  2014  includes a radiopaque marker (not shown). Non-limiting examples of metals suitable for use as either the radiopaque marker  2008  of the detachment system  2004  or the radiopaque marker on the catheter include noble metals or alloys such as platinum, platinum-tungsten, platinum iridium, silver, or gold. In some embodiments of the delivery system  2000 , the radiopaque marker  2008  of the detachment system  2004  and the radiopaque marker on the catheter  2014  are positioned so that they align with one another so when a detachment mechanism  2005  is positioned at a deployment location  2009 . In some embodiments of the delivery system  2000 , the radiopaque marker  2008  of the detachment system  2004  and the radiopaque marker of the catheter  2014  are positioned so that they align at a location about 30 mm proximal to the deployment location  2009 . 
         [0045]    In some embodiments of the delivery system  2000 , a detachment system  2004  includes a radiopaque marker coupler  2008  at a radiopaque marker location. The radiopaque marker coupler  2008  is a portion of the detachment system  2004  that is configured to couple with a radiopaque marker  2006 . That is, a radiopaque marker  2008  of the detachment system  2004  typically comprises a metal such as, for example, platinum, platinum-tungsten, platinum iridium, silver, or gold. Because the remaining portions of the detachment mechanism  2005  (except in some embodiments the primary member  2018  is not) comprise a memory material such as nitinol, coupling the radiopaque marker  2008  to the detachment mechanism  2005  is not easily achievable with typical methods such as welding due to differences between the materials (i.e. between the radiopaque marker  2008  and the memory material of the detachment mechanism  2005 ). As such, a radiopaque marker coupler  2008  is configured to couple with a radiopaque marker  2006  mechanically without the need for the two elements to be welded or similarly fused. In some embodiments of the detachment system  2004 , a radiopaque marker coupler  2008  have complimentary shapes that are configured so that the two components couple together by fitting together as shown in  FIG. 2 . That is, in some embodiments of the detachment system  2004 , a radiopaque marker coupler  2008  is a component of the detachment mechanism  2005  that has an alternating tooth pattern (as shown) with elevations and indentations or alternatively, for example, a saw-tooth pattern, and likewise the radiopaque marker  2009  has a complimentary alternating tooth pattern (as shown) with elevations and indentations or alternatively, for example, a saw-tooth pattern so that the two components, the radiopaque marker coupler  2008  and the radiopaque marker coupler  2009 , fit together wherein an elevation of one component fits an indentation of the complimentary component. In some embodiments of the detachments system  2004 , a flexible shrink tube  2002  tightly surrounds these two coupled components, the radiopaque marker coupler  2008  and the radiopaque marker coupler  2009 , so that they are fixedly coupled together. 
         [0046]    In order for the detachment system  2004  to properly deploy an implant such as an embolic coil within an aneurysm (i.e. the target), the detachment mechanism  2005  must be advanced to a deployment location  2013  along the catheter  2014 . The deployment location  2013  may be a different location along the catheter  2014  depending on the type of implant deployed. For example, in some embodiments of the delivery system  2000 , for proper deployment of an embolic coil or other implant within an aneurysm or other target location, the embolic coil or other implant is advanced entirely out of the aperture  2009  of the catheter  2014 . For example, in some embodiments of the delivery system  2000 , for proper deployment of an embolic coil or other implant within an aneurysm or other target location, the embolic coil is advanced partially out of the aperture  2009  of the catheter  2014 . For example, in some embodiments of the delivery system  2000 , for proper deployment of an embolic coil or other implant within an aneurysm or other target location, the detachment mechanism is advanced entirely out of the aperture  2009  of the catheter  2014 . In some embodiments of the delivery system  2000 , for proper deployment of an embolic coil or other implant within an aneurysm or other target location, the detachment mechanism  2005  is advanced partially out of the aperture  2009  of the catheter. As shown in the exemplary embodiment shown in  FIG. 2 , a detachment mechanism  2005  in the illustrated embodiment, is positioned within the distal portion of the catheter  2014  for proper deployment of an implant and as such the deployment location  2013  in the embodiment shown in  FIG. 2  is located at the distal end of the catheter  2014 . 
         [0047]    That is, as shown in  FIG. 2 , the distal end  2016  of the catheter defines a deployment location  2013 , which is a position or zone to where the detachment system  2004  (and thus the detachment mechanism  2005  at the distal end of the detachment system) must be advanced in order to achieve successful deployment of an implant. For example, in embodiments of the delivery system wherein the detachment system  2004  remains entirely within the distal end of the catheter  2014  in order to achieve proper deployment of an implant, the deployment location  2013  is located where the detachment system  2004  is positioned within the distal end  2016  of the catheter. For example, in embodiments of the delivery system wherein the detachment system  2004  is partially out of the aperture  2009  at the distal end  2016  of the catheter and partially within the distal end  2016  of the catheter in order to achieve proper deployment of an implant, the deployment location is located partially outside of the aperture  2009  and partially within the catheter where the detachment system  2004  is positioned. For example, in embodiments of the delivery system wherein the detachment system  2004  is completely out of the aperture  2009  in order to achieve proper deployment of an implant, the deployment location is located where the detachment system  2004  is positioned outside of the catheter. 
         [0048]    In general, the proximal end  2017  of catheter  2002  is coupled to one or more features that provide a user with manual control over the advance of the implant to the target and deployment of the implant at or in the target. In some embodiments of the delivery system  2000 , the proximal end  2017  of the catheter  2002  is coupled with an expansion tube  2026 . The expansion tube  2026  is configured to have a larger diameter than the relatively small diameter of the micro-catheter  2002 . The expansion tube  2026  is generally configured so that it may couple the delivery system  2000  to other elements. For example, in some embodiments of the delivery system  2000 , the expansion tube  2026  couples to a grip tube  2012  at the most proximal end  2017  of the delivery system  2000 . The grip tube  2012  provides a user with a manual grip to advance and/or withdraw the detachment system in order to guide the detachment system through the vasculature of a patient. In some embodiments of the delivery system  2000 , the expansion tube  2026  includes one or more oblong cuts or breaks within its material in order to facilitate a manual fracturing of the expansion tube  2026  so that the expansion tube  2026  is divided. Manually dividing the expansion tube  2026  provides a mechanism for withdrawing the fractured portion of the expansion tube  2026  away from the detachment system in a proximal direction, which is used in some embodiments of the delivery system  2000  to manually trigger deployment of an implant. In some embodiments of the delivery system  2000 , the expansion tube  2026  couples with an external detachment device that is configured to manually trigger deployment of an implant using the detachment system  2004   
         [0049]    Detachment Mechanism 
         [0050]    In some embodiments of the systems, devices, and methods described herein, a detachment mechanism  2005  is positioned at the distal end  2016  of the detachment system  2004 , and the detachment system  2004  along with the catheter  2014  form the delivery system  2000 . 
         [0051]    In some embodiments, a detachment mechanism  2005  comprises a primary member  2018 , an anchoring member, and a tab, which are configured and positioned to actuate the detachment mechanism  2005  causing the release and/or deployment of an intravascular implant. 
         [0052]    A primary member  2018  as shown in  FIG. 2  is configured in some embodiments so that it is long enough to extend the length of the delivery system  2000  when the deployment mechanism  2005  is at the deployment location  2009 . 
         [0053]    A number of additional features of embodiments of the detachment mechanism  2005  are now described with additional reference to  FIG. 3  as well as further reference to  FIG. 2 : 
         [0054]      FIG. 3  shows an illustration of an exemplary embodiment of a detachment mechanism  3005  which comprises an embolic coil  3022  (or other implant) that is detachably coupled to the detachment mechanism  3005 . 
         [0055]    The detachment mechanism  3005  comprises elements that are configured to cause the deployment of an intravascular implant  3022 . In some embodiments, the detachment mechanism  3005  includes a tab  3016 , an optional primary member  3018 , and an optional anchoring element  3020 . 
         [0056]    A tab  3016  of a detachment mechanism  3005  is configured to have at least two configurations or positions, at least a first configuration or position and a second configuration or position. In a first configuration or position of the tab  3016 , an embolic coil  3022  is held or coupled with the tab  3016 , and in a second configuration or position of the tab  3016  releases or decouples from an embolic coil  3022 . In some embodiments of detachment system, a tab  3016  is either a portion of or integral with a housing  3024 . In some embodiments of the delivery system  3000 , a tab  3016  comprises a memory metal or other memory material such as nitinol. A housing  3024  is configured to contain at least a portion of an embolic coil  3022  and, in some embodiments, an anchoring element  3020  that is coupled with the embolic coil  3022 . 
         [0057]    In some embodiments of the detachment mechanism  3005 , a tab  3016  of a detachment mechanism  3005  detachably couples with a distal portion of a primary member  3018 . In these embodiments, while coupled with the primary member  3018 , the tab  3016  is in a first position wherein the tab  3016  is depressed or deflected towards the interior of the housing  3024 . When the tab  3016  is deflected towards the interior of the housing  3024  in its first position, it is positioned to couple directly with either an embolic coil  3022  that is at least partially within the housing  3024  or, in some embodiments, couple indirectly with an embolic coil  3022  by coupling with an anchoring element  3020  that in some embodiments is coupled with an embolic coil  3022 . By virtue of coupling to the tab  3016  in its first position, the embolic coil  3022  is held within the housing  3024  of the detachment system  3016 . 
         [0058]    In some embodiments of the detachment mechanism  3005 , an embolic coil  3022  (or other intravascular implant) is coupled with an anchoring element  3020  that is configured to couple with a tab  3016 . In these embodiments, an anchoring element is configured to releasably couple with a tab  3016  when the tab  3016  is in the first position and deflected towards the interior of the housing. For example, in some embodiments of the delivery system  3000 , as shown in  FIG. 3 , an anchoring element  3020  comprises a sphere or ball and when the tab  3016  is in its first position, it hooks or latches the ball  3020  so that the ball  3020  is held within the housing  3024  and thus the embolic coil  3022  is held by the detachment mechanism  3014 . 
         [0059]    In embodiments of the detachment mechanism  3005  that include a primary member  3018 , when the primary member is coupled with the tab  3016  it holds the tab  3016  in the first position of the tab  3016  so that the tab  3016  is deflected towards the interior of the housing  3024 . When the primary member  3018 , in these embodiments, is decoupled from the tab by being, for example, withdrawn in a proximal direction, the tab  3016  moves away from the interior of the housing  3024  to move to a second position. In embodiments where the tab  3016  comprises a memory material, the material of the tab  3016  facilitates its movement away from the interior of the housing  3024  when decoupled from the primary member  3018 . In some embodiments of the system  3000 , a primary member is withdrawn proximally by a user when the detachment system is positioned near a target location such as, for example, an intracranial aneurysm. A primary member  3018  may, for example, comprise a wire that extends out of the proximal end  3017  of the catheter  3002  to a location where the wire may be pulled proximally by a user thus decoupling the primary member  3018  and the tab  3016 . 
         [0060]    In some embodiments of the detachment system  3004 , an expansion tube  3026  is configured to fracture so that at least a portion of the expansion tube  3026  may be withdrawn in a proximal direction away from the rest of the detachment system. In some of these embodiments, a primary member  3018  is coupled with an expansion tube  3026  so that when the expansion tube  3026  is fractured and withdrawn in a proximal direction, the primary member  3018  is decoupled from the tab  3016  so that the tab  3016  moves from the first position to the second position and causes the release of the embolic coil  3022 . In some embodiments of the delivery system  3000 , a primary member  3018  comprises a wire that spans the length of the detachment system and extends out to a hand-held detachment device. In these embodiments, the hand-held detachment device includes a manually operated clamp that is configured to grip the primary member  3018  and withdraw it in a proximal direction thus decoupling the primary member  3018  from the tab  3016  so that the tab  3016  moves from the first position to the second position and causes the release of the embolic coil  3022 . 
         [0061]      FIG. 4  shows an illustration of an embodiment of a distal end of a detachment mechanism  4005  showing how an intravascular implant is deployed from a detachment system  4014 . As described with reference to  FIG. 2 , a tab  4016  has at least a first position and a second position. In the second position of a tab  4016 , the tab  4016 , as shown in  FIG. 4 , is positioned so that it is not deflected towards the interior of a housing  4024  but rather positioned away from the interior of the housing  4024 . Primary member  4018  is shown being withdrawn away from and thus decoupled from the tab  4016 . As such, an anchoring element  4020  is no longer held by the detachment system  4014  and an embolic coil (not shown in  FIG. 4 ) is released or deployed at a target location. 
         [0062]    Expansion Tube 
         [0063]      FIG. 5  shows an exemplary illustration of an embodiment of an expansion tube  5026 . As described with reference to  FIGS. 1 and 2 , some embodiments of detachment system include an expansion tube  5026  at the proximal end  2017  of the system. In some of these embodiments, an expansion tube  5026  includes one or more cuts  5030  at least partially surrounding the diameter of the expansion tube  5026  so that the cuts  5030  are positioned and/or configured to facilitate a fracture of the expansion tube  5026  when a bend is applied to the expansion tube  5026  by a user. Also shown in  FIG. 5  is a primary member  5018  within the expansion tube  5026 . In some embodiments of the delivery system  2000 , an expansion tube  5026  may be further coupled at its proximal end  2017  to a hand-grip (not shown in  FIG. 5 ) that is configured to allow a user to control the advancement and withdrawal of the catheter as well as control over the manual deployment of an implant. As described with reference to  FIGS. 1-2 , a primary member  5018 , in some embodiments of detachment system, is connected to either an expansion tube  5026  or a hand-grip. When the expansion tube  5026  is fractured, the fractured portion of the expansion tube  5026  (and some embodiments along with a hand-grip) is able to be withdrawn away from the catheter in a proximal direction. In some embodiments of detachment system, when the expansion tube  5026  is fractured so that detachment system separates into a distal piece and a proximal piece that are able to be withdrawn from one another, the primary member  5016  is no longer held against the tab  2016 , so that the tab moves to a second position (facilitated by the memory material), which exerts a force on the primary member  5016  driving it proximally. 
         [0064]    Hand-Held Detachment Device 
         [0065]      FIGS. 6A-6B  show an illustration of an alternative mechanism for manually deploying an intravascular implant using a hand-held detachment device  6032 .  FIG. 6A  shows a perspective view of a hand-held detachment device  6032  which includes a housing  6034  and an actuator switch  6036 . Also shown is a primary member  6018 , which in the illustrated embodiment comprises a wire, passing into the interior of the hand-held detachment device  6032 . While not shown in  FIGS. 6A-6B , the hand-held detachment device  6032  is located at the proximal end  2017  of detachment system is configured to allow a user to manually withdraw the primary member  6018  in a proximal direction thus deploying the implant as described.  FIG. 6B  shows a cross-sectional view of a hand-held detachment device  6032  which includes cam clamps  6038   a  and  6038   b  along with spring  6040 . In operation, a user engages actuator  6036  which causes clamping cams  6038   a  and  6038   b  to withdraw in a proximal direction. In some embodiments of the delivery system  2000 , the clamping cams grip the grip tube at the distal end  2016  of the delivery device  2000  which in these embodiments is connected to the primary member so that when the clamping cams  6038   a  and  6038   b  are withdrawn in a proximal direction the primary member is withdrawn in a proximal direction as well resulting in the tab changing from a first position to a second position as described. Spring  6040  provides resistance to prevent inadvertent activation of the clamping cams  6038   a  and  6038   b  and thus inadvertent deployment of the intravascular implant. 
         [0066]      FIG. 7  shows an illustration of a close-up view of a cross-section of the hand-held detachment device  6032  which shows clamping cams  7038   a  and  7038   b  griping a grip tube  7012  of the delivery system  7000 . Clamping cams  7038   a  and  7038   b  are activated by the actuator switch  7036 , which causes proximal movement of the clamping camps  7038   a  and  7038   b  by, for example, being slid in a proximal direction by a user. In some embodiments of the hand-held detachment device  7032 , the actuator switch  7036  causes the clamping cams  7038   a  and  7038   b  to both grip the grip tube  7012  and move proximally. In these embodiments, the clamping cams  7038   a  and  7038   b  only grip the grip tube  7012  when the actuator switch  7036  is engaged as a safety feature to prevent inadvertent withdrawal of the primary member. 
         [0067]      FIGS. 8 a    and  8 B show illustrations of what a user sees in a viewing window  8042 , wherein the viewing window  8042  is a feature of some embodiments of the hand-held detachment device as described. A viewing window  8042  is configured to show a user a visual confirmation that the grip tube  8012  has been withdrawn proximally by the hand-held detachment device. In  FIG. 8A , a viewing window  8042  shows an expansion tube  8024  and grip tube  8012  indicating that the grip tube  8012  has not been withdrawn in a proximal direction and the primary member is therefore coupled to the tab of the detachment system. In  FIG. 8B , a viewing window  8042  shows an expansion tube  8024  only indicating that the grip tube  8012  has been withdrawn in a proximal direction and the primary member is decoupled from the tab of the detachment system. 
         [0068]    The steps of an exemplary method for deploying an intravascular implant at a target location, using any of the embodiments of the systems described herein, is as follows: Providing a user with a delivery system  2000  as shown in  FIG. 2  which comprises a catheter  2002  and a detachment system  2004 . 
         [0069]    The steps of an exemplary method for deploying an intravascular implant at a target location, using any of the embodiments of the systems described herein, is as follows: Receiving a delivery system  2000  as shown in  FIG. 2  which comprises a catheter  2002  and a detachment system  2004 . Advancing the delivery system  2000  to an anatomical target location such as an intracranial aneurysm. Advancing the detachment system  2014  within the catheter  2002  so that the implant is advanced into the target location (i.e. the embolic coil is advanced within the aneurysm). Determining that the detachment system  2014  is in the detachment location by radiographically visualizing an alignment of an alignment of a first radiopaque marker on the catheter and a second radiopaque marker on the detachment system  2014 . Alternatively or additionally, determining that the detachment system  2014  is in the detachment location by sensing a resistance to further advancement of the detachment system  2014  caused by the interlocking system coupling the catheter  2002  and the detachment system  2014  at the location of the first radiopaque marker. Alternatively or additionally, determining that the detachment system  2014  is in the detachment location by viewing the absence of a visible grip tube within a viewing window of a hand-held detachment device. 
         [0070]    The steps of an exemplary method for deploying an intravascular implant at a target location, using any of the embodiments of the systems described herein, is as follows: Moving, by the withdrawal of a primary member from a tab of a detachment system, the tab from a first position in which it is coupled to an embolic coil or an anchoring element coupled to an embolic coil to a second position in which the tab decouples from either the embolic coil or the anchoring element thereby deploying the embolic coil. 
         [0071]    The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. 
         [0072]    The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.