Interlocking Loop Connection / Detachment System for Deploying Vascular Implant Devices - Patent application

Abstract

To provide a release / removal mechanism for an implant device that is easy to manufacture and use. [Solution] In a system and method for deployment of an implant device, the implant device includes a first loop at its proximal end and the deployment tool has a second loop attached to its distal end. A release wire slidably disposed within the deployment tool extends through the first and second loops and has a distal end that releasably couples the implant device to the deployment tool and a proximal portion that extends from the proximal end of the deployment tool and is held by a retraction device. The retraction device is operable to hold the proximal end of the deployment tool and pull the release wire proximally through the deployment tool until the distal end of the release wire is withdrawn from the first and second loops, separating the implant device from the deployment tool.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 62 / 584,047, filed November 9, 2017, the disclosure of which is incorporated herein by reference in its entirety. Federally funded research and development Not applicable.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to the deployment of vascular implants, such as vaso-occlusive devices, and related methods. More particularly, the present disclosure relates to systems, devices and methods for the deployment and release of vascular implant devices at a target vascular site. [Background technology]

[0003] In certain implant procedures, such as those used to occlude a vascular cavity or other body lumen, an implant device is inserted into the body and released at a target site within the lumen. For example, a vascular occlusion implant device may be inserted into a blood vessel to close or seal the blood vessel or to close a cardiac defect. To insert the implant device, the implant device may be advantageously removably or releasably coupled to the end of a deployment tool and deployed within the blood vessel via a delivery device, such as a microcatheter. After placement of the implant device at the target site, the implant device is released or detached from the deployment tool by an appropriate release mechanism, and the deployment tool is free to be withdrawn.

[0004] It is important that release or removal of the implant device occur with minimal application of axial force to the implant device to minimize movement of the device from its optimal position at the target vascular site. To this end, release mechanisms have been devised that use, for example, heat fusible links that break in response to the application of thermal energy, for example via an electric current. Other release mechanisms use links that are severed by a shearing or cutting instrument. While these mechanisms may achieve, to varying degrees, the objective of minimizing the transmission of axial force to the implant device, they are often complex and costly to manufacture and / or cumbersome to use.

[0005] Furthermore, conventional endovascular implant deployment tools require engagement of a release wire through all phases of motion required to separate the implant from the deployment tool, however this means that in addition to the release wire being pulled back by actuation of the deployment tool, the release wire can also be pushed by the deployment tool.

[0006] It therefore remains a goal of the related art to provide a release / removal mechanism for an implant device that is easy to manufacture and easy to use while still meeting the required clinical standards. Summary of the Invention

[0007] The present disclosure relates to embodiments of a system for separating a deployed implant device from a deployment tool to which the implant device is coupled during deployment, where the deployment tool having the implant device attached to its distal end is passed through an intravascular microcatheter to reach a vascular target site. The disclosed embodiments include a retraction device for engaging and withdrawing a release wire having a distal end that releasably couples the implant device to a deployment tool, and a system for releasably coupling the implant device to the distal end of the deployment tool. Certain embodiments of the disclosed detachment system use interlocking loops to couple the implant device to a deployment tool.

[0008] In one aspect, the present disclosure relates to an interlocking loop coupling / detachment system configured to allow a user to detach or release a vascular implant device from a deployment tool through a single motion on a retraction device. More specifically, the systems disclosed herein include an interlocking loop coupling mechanism for releasably coupling the implant device to the deployment tool by a release wire, and a release wire retraction device that retracts the release wire to separate the implant device from the deployment tool without applying significant axial forces to the implant device.

[0009] The single action retraction device of the present disclosure can avoid reinsertion of the release wire because the retraction device does not act on the release wire at all stages of movement. Instead, the retraction device only acts on the release wire during retraction of the release wire, and the retraction device can be reset for use with a different deployment tool and implant device. While the systems and methods described herein are particularly useful for the intravascular deployment of vascular occlusive implants, they may also be useful for the deployment of stents, coils, plugs and other implant devices for therapeutic or diagnostic benefit to a patient.

[0010] In one aspect, a system for deploying a vascular implant according to the present disclosure includes: an implant assembly having a proximal end and a distal end, the first loop being attached to the proximal end of the implant assembly; a deployment tool having a proximal end and a distal end, the second loop being attached to the distal end of the deployment tool; a release wire slidably disposed within the deployment tool and having a proximal end and a distal end, the distal end of the release wire extending through the first and second loops to releasably couple the implant assembly to the deployment tool, and the proximal end of the release wire extending proximally from the proximal end of the deployment tool; a release wire retraction device operable to (a) hold a proximal end of the deployment tool, (b) releasably grasp a proximal end of the release wire, and (c) pull the release wire proximally through the deployment tool until a distal end of the release wire is withdrawn from the first and second loops and the implant assembly is separated from the deployment tool. It is equipped with:

[0011] In another aspect, a method of coupling and detaching an implant device from a deployment tool is disclosed. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view with partial cutaway of a release wire retraction device for use with an interlocking loop implant coupling system according to one aspect of the present disclosure. [Diagram 2] FIG. 13 is a partial cross-sectional view of the retraction device in a first, unclamped, unactuated state. [Diagram 3] FIG. 13 is a partial cross-sectional view of the retraction device in a second clamped, unactuated state. [Figure 4] FIG. 13 is a partial cross-sectional view of the retraction device in a third clamped, actuated state. [Diagram 5] FIG. 13 is a partial cross-sectional view of the retraction device in a fourth, unclamped, actuated state. [Figure 6] FIG. 13 is a partial cross-sectional view of a pullback device in a fifth reset state. [Figure 7] FIG. 13 is a partial cross-sectional view of a pullback device in a sixth reset state. [Figure 8]FIG. 13 is a partial cross-sectional view of an interlocking loop coupling / detachment system configured to decouple a deployed implant device from a release wire prior to activation. [Figure 9] FIG. 9 is a side view of the distal end of the interlocking loop coupling system and implant device of FIG. 8. [Figure 10] FIG. 13 is a partial cross-sectional view of the interlocking loop coupling system after separation. [Figure 11] FIG. 13 is a side view of the distal end of the interlocking loop coupling system and implant device after separation. [Figure 12] 8A-8C show exemplary guide tracks for a guide arm around a cam ramp of the retraction device of FIGS. 1-7. [Figure 13] 1A-1C show an embodiment of a coupling system having a release wire ferrule and a stop tube. [Figure 14] FIG. 14 is a cross-sectional view taken along line AA in FIG. [Figure 15] FIG. 14 is a cross-sectional view taken along line BB in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of a presently preferred embodiment of an interlocking loop implant connection / detachment system with a release wire retraction device provided in accordance with aspects of the present disclosure. It is not intended to represent the only manner in which the presently disclosed components, assemblies and methods can be constructed or used. The description explains the features and steps for constructing and using the presently disclosed components, assemblies and methods embodiments in conjunction with the illustrated embodiments. However, it should be understood that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the present disclosure. As shown elsewhere herein, like element numbers are intended to indicate like or similar elements or features.

[0014] 1-7 show partial cutaways of an exemplary embodiment of a retraction device 10 for an interlocking loop implant connection / detachment system according to the present disclosure, showing half of a housing 100 and cross-sectional views of a guide assembly 200, an actuator 300 and a release wire guide 400. In some embodiments, the guide assembly 200 and the actuator 300 may be integrally formed as a unit. Alternatively, the guide assembly 200 and the actuator 300 may be separate, mechanically connected components. Guide assembly 200 and actuator 300 may be understood to be symmetrical along an axis extending from the distal or leading end 110 to the proximal or trailing end 112 of retraction device 10 (the terms "distal" and "proximal" as used in this disclosure are taken from the perspective of a user of device 10). Accordingly, the other half (not shown) of guide assembly 200 and actuator 300 may be understood to mirror the half shown in Figures 1-7. For ease of assembly, the housing 100 may advantageously be made from two axial halves which are joined together by adhesive or other suitable bonding / welding means after installation of the internal components. To this end, each housing half is provided with complementary male locating pins 106 and female locating sockets 107. Any suitable durable plastic or polymeric material is suitable for the housing, although the housing may also be made of any suitable metal or alloy. Embodiments of the retraction device 10 can be made from components formed by a manufacturing process such as injection molding or machining. Optionally, a forming process such as 3D printing can also be used. The housing 100, when fully assembled, should be of advantageous outer dimensions and configuration as a handpiece that can be comfortably and securely held and manipulated when the device is in use.

[0015] The housing 100 of the retraction device 10 includes a guide assembly 200 , an inner body 302 of an actuator 300 , and a release wire guide 400 . The actuator 300 and guide assembly 200 are axially movable relative to the housing 100 between distal and proximal positions by manipulation of a finger grip 304 on the exterior of the housing 100. Specifically, an inner body 302 of the actuator 300 is connected to the finger grip 304 by a connecting portion or stem 306 that extends through a longitudinal slot 308 in the top of the housing 100. The guide assembly 200 is, in turn, connected to the inner body 302 of the actuator 300 such that the guide assembly 200 can move therewith. The top of the housing 100 includes a planar track surface 104 upon which a finger grip 304 is slidably seated. The slots 308 and track surface 104 are configured to define a path for longitudinal movement of the guide assembly 200 and actuator 300 relative to the housing 100. The guide assembly 200 may include a side wall 200a, a bottom wall or base 200b, and a top wall 302. Together, these generally define a central space for the operating components of the guide assembly 200, as described below.

[0016] In an embodiment of retraction device 10, guide assembly 200 may include a guide groove or track 120 that provides a guide path around cam ramp 128, guide lever 210, and a fixed release wire gripping element 220, which may be referred to as an "anvil." (It is understood that the other half of housing 100, not shown, is provided with a corresponding guide track 120.) The anvil 220 may be attached to at least one of the side wall 200a and the top wall 302 of the guide assembly 200. The anvil 220 may be aluminum or a similar metal, or may be a durable polymer or composite material. The guide lever 210 may be rotatably pinned near its distal end to at least one of the side walls 200 a of the guide assembly 200 by a hinge pin 211 . The guide lever 210 may further include a movable gripping element 212. The movable gripping element 212 is provided as a guide lever insert located near the distal end of the guide lever 210 and is configured such that the movable gripping element 212 can move toward and away from the anvil 220 as the guide lever 210 pivots (as described below). This allows a proximal end of a release wire 802 extending from an end of a deployment tool sheath 800 inserted into the distal end 110 of the housing 100 to be gripped between the movable gripping element 212 and the anvil 220. The movable gripping element 212 may be an insert within the guide lever 210 as shown, or may be integral with the guide lever 210. The movable gripping element 212 may have any suitable shape for providing a secure, yet releasable engagement of the guidewire to the fixed gripping element or anvil 220.

[0017] The guide lever 210 has a free proximal end that terminates in a pair of guide arms 216 (only one of which is shown), each of which is seated in a guide track 120 in a corresponding housing half. The guide lever 210 is biased upwardly by a guide lever biasing spring 214 (FIGS. 2-7) and is guided to move along a continuous closed path provided by the guide track 120 seated therein as the actuator 300 and guide assembly 200 are moved to their different positions as described below with reference to FIGS. 2-7.

[0018] As best shown in FIG. 1 , the guide assembly 200 may further include a spring support 204 extending proximally from the top wall 302. An axially oriented forward biasing spring 700 may be positioned such that a first end surrounds the spring support 204 and abuts a spring seat formed by the junction of the spring support 204 and the top wall 302. The forward biasing spring 700 extends proximally through a spring chamber defined between the upper and lower chamber walls 114a, 114b and terminates at a second end seated in the proximal spring seat 115. In this manner, the forward biasing spring 700 provides a distal biasing force to the guide assembly 200, thereby biasing the guide assembly 200 against rearward (i.e., proximal) movement within the housing 100.

[0019] The distal end 110 of the housing 100 includes a distal opening 111. A deployment tool 800, including a release wire 802, can enter the release wire guide 400 of the retraction device 10 through the distal opening 111. In an embodiment of the present disclosure, the deployment tool 800 can be a sheath in which the release wire 802 is axially and slidably disposed (for purposes of this description, the deployment tool will be referred to as a "sheath," although other configurations may be used for the deployment tool). The release wire guide 400 may advantageously have a conical entrance 402 that tapers inwardly and proximally to the axial passageway 404. This tapered shape allows the sheath 800 having the release wire 802 to be inserted by the user while the guide assembly 200 is positioned for insertion through it. The sheath 800 may be advantageously retained within the passageway 404 by a sheath retention device 450, such as a ball nose spring plunger or other similar retention element or mechanism housed in the proximal portion 410 of the release wire guide 400, which provides a radial retention force to the sheath 800. This holds the proximal end of the sheath 800 in a fixed position when the release wire 802 is pulled proximally through the sheath 800 by the retraction device 10, as described below. In some embodiments, the sheath retaining device 450 can be an integrated unit, such as a spring plunger of the type commercially available from Vlier Products (www.vlier.com). In other embodiments, the sheath retaining device 450 can include separate components, such as a ball bearing, a spring, and a set screw. The release wire guide 400 may be a separate component from the housing 100 or may be integrally molded with the housing 100. The sheath retention device 450 may be attached to the release wire guide 400 by a threaded connection or by alternative means such as, for example, adhesives, fasteners, or other suitable methods.

[0020] 2-7 are partial cross-sectional views of retraction device 10 at various stages of an actuation cycle for linear proximal movement of a release wire by manual operation of actuator 300. FIG. The operations described below are defined in terms of a series of steps or stages, each of which corresponds to a position of the actuator 300 and the guide assembly 200 , and in particular the position of the guide arm 216 within the guide track 120 . The path defined by the guide track 120 followed by the guide arm 216 defines a closed loop shape that may be, for example, generally oval, elliptical, trapezoidal, diamond, rectangular, triangular, etc. In the illustrated exemplary embodiment, the guide track 120 has a generally trapezoidal shape. In operation, the mobile gripping element 212 can be disengaged from the release wire 802 at the distal-most and proximal-most positions of the path. The mobile gripping element 212 can be engaged with the release wire 802 at intermediate positions of the path between the distal-most and proximal-most positions.

[0021] 2 shows the retraction device 10 in a first, unactuated stage, considered to be the "rest position." In this first stage, the guide arm 216 is disposed at a first or start position 122b of the guide track 120. The start position 122b is between the lower distal portion 122a and the upper distal portion 122c of the guide track 120. In this first stage, the actuator 300 is in a forward (distal) position and the forward biasing spring 700 biases the guide assembly 200 forward (distal). Additionally, the guide lever biasing spring 214 biases the guide lever 210 upward toward the actuator 300. The combined forces of the forward biasing spring 700 and the guide lever biasing spring 214 cause the guide arm 216 to come to rest against the start position 122b of the guide track 120. At this point, in some embodiments, the guide lever 210 is positioned such that the movable gripping element 212 does not contact the proximal portion of the release wire 802 that extends proximally out of the sheath 800.

[0022] 3 shows the retraction device in a clamped but unactuated second stage in which the actuator 300 is moved rearward (proximally) by the user along the upper track surface 104 to a first intermediate position. In this position, the guide assembly 200 moves rearward (proximally) such that the guide arm 216 is shifted away from the starting position 122b of the guide track 120, thereby allowing the guide lever biasing spring 214 to bias the proximal end of the guide lever 210 upwardly as the guide arm 216 tracks toward the upper distal portion 122c of the guide track 120. In this condition, rearward movement of the actuator 300 and guide assembly 200 compresses the forward biasing spring 700 . When the guide lever 210 is biased upward, the release wire 802 is gripped between the movable gripping element 212 and the anvil 220, and as the guide assembly 200 is moved proximally along with the actuator 300, the release wire 802 begins to be pulled back (proximally) into the housing 100 in proportion.

[0023] Figure 4 illustrates the retraction device in a third stage of actuation, in which the actuator 300 is moved further rearward (proximally) by the user along the upper track surface 104 from the first intermediate position shown in Figure 3 to a rearward (proximal) second intermediate position. In this position, the guide assembly 200 has been moved rearward (proximally) such that the guide arm 216 is positioned at the first or upper proximal portion 126 of the guide track 120 and the proximal end of the cam ramp 128 . In the illustrated exemplary embodiment, in which the guide track 120 has an approximately trapezoidal shape, rearward movement of the guide lever 210 positions the guide arm 216 at the first proximal portion 126 of the guide track 120, while moving the distal end of the guide lever 210 (where the movable gripping element 212 is located) away from the release wire 802. Due to the inclination of the proximal portion of the guide track 120, the guide lever 210 is biased downward against the biasing force of the guide lever biasing spring 214, thereby disengaging the gripping insert 212 from engagement with the release wire 802, thus stopping proximal movement of the release wire 802 into the housing 100. The distance that the release wire 802 advances proximally into the housing between the second and third stages (Figures 3 and 4, respectively) before the release wire 802 is stopped is determined primarily by the length of the path that the guide arm 216 travels within the guide track 120 from the second distal portion 122c to the first proximal portion 126 of the guide track.

[0024] 5 shows the retraction device in a fourth stage of operation, in which the actuator 300 is in its rearmost (proximal) position along the upper track surface 104. In this position, the guide assembly 200 has moved rearward such that the guide arm 216 has passed the proximal end of the cam ramp 128 and is at the second or lower proximal portion 127 of the guide track 120. The actuator 300 and guide assembly have now reached the limit of their proximal travel against the biasing force of the forward biasing spring 700. Similarly, the guide lever 210 moves downward against the biasing force of the guide lever biasing spring 214 to the bottom of its range of travel, thereby moving the movable gripping element 212 further away from (and out of engagement with) the release wire 802 .

[0025] The guide arm 216 may move in a closed path in which the longitudinal distance L (parallel to the axis of movement of the sheath 800 and release wire 802) is greater than the lateral distance T, as shown in FIG. In some embodiments, the ratio of longitudinal distance to lateral distance (L / T) is at least 1.25, and may be between about 1.5 and 15. In some embodiments, the passage may define a closed shape having between about 3 and 6 substantially straight sides. An exemplary closed loop travel path 216p of the guide arm 216 around the cam ramp 128 is illustrated in FIG. 12 with dashed lines indicating various positions 216', 216'' and 216''' in the travel path.

[0026] 6 and 7 show the retraction device in a fifth, reset stage in which the actuator 300 and guide assembly 200 move forward towards the distal end 110 of the retraction device 10. When the finger grip 304 of the actuator 300 is released, the forward biasing spring 700 biases the actuator 300 and guide assembly in a distal direction. Due to the geometry of the guide track 120, the guide arm 216 follows a path of movement below the cam ramp 128 as opposed to the actuation stages (i.e., the third and fourth stages shown in Figures 4 and 5, respectively) where the guide arm 216 follows a path of movement above the cam ramp 128. As the guide arm 216 moves distally in the portion of the guide track 120 below the cam ramp 128, the proximal end of the guide lever 210 is rotated downward (clockwise as shown in the drawings) against the upward bias of the guide lever biasing spring 214. At this time, the guide lever biasing spring 214 is further compressed. Clockwise rotation of the guide lever 210 moves the movable gripping element 212 further away from the release wire so that the axial position of the release wire 802 within the housing 100 is not changed or affected when the actuator 300 and guide assembly 200 are moved distally by the forward biasing spring 700 back to the first stage shown in FIG. 2.

[0027] 7 shows the actuator 300 and guide assembly 200 retracted distally closer to the position shown in FIG. 2, closer to the distal end 110 of the retraction device 10 than shown in FIG. The guide arm 216 continues to follow the path of travel down the camming ramp 128 until the guide arm 216 reaches the distal end of the camming ramp 128 . In the path of travel of the guide arm 216 below the cam ramp 128, with the movable gripping element 212 remaining disengaged from the release wire 802, the guide lever 210 is maintained at the lower part of its range of travel shown in FIG. As the guide arm 216 moves further distally within the guide track 120 , the guide arm 216 passes the distal end of the cam ramp 128 . As the guide arm 216 enters the first distal portion 122a of the guide track 120, the guide lever biasing spring 214 biases the guide lever 210 back to the first or start position 122b of the guide track, as shown in FIGURE 2, where the gripping element 212 is no longer in contact with the release wire 802. At this point, the retraction device is reset to the first or rest stage shown in FIGURE 2. During or after resetting the retraction device (i.e., when the movable gripping element releases the guidewire 802), the retraction device 10 may be separated from the sheath 800 and the guidewire 802, thereby enabling the retraction device 10, once reset, to be used for separating another implant device.

[0028] In summary, Figures 2-7 show a series of operational steps or stages of the retraction device 10 operable to retract or withdraw the release wire 802 from an implant deployed at a target vascular site, whereby the withdrawal is accomplished in one direction (i.e., proximally) without disturbing or displacing the implant or applying significant axial forces to the implant or deployment tool.

[0029] Different shapes of the guide track 120 and the cam elements 128 may be provided. In the exemplary embodiment shown, a generally trapezoidal shape of the guide track 120 is provided with a ramp-shaped cam element 128. However, alternative guide track and cam element shapes can be used to achieve the result of retracting the release wire during actuation while allowing the guide assembly to be reset without reversing the direction of movement of the release wire 802 (i.e., without advancing the release wire 802).

[0030] The fulcrum (ie, pin 211) of guide lever 210 and / or the shape of guide lever 210 may be defined such that the movement of guide arm 216 differs from that of the embodiment shown in Figures 2-7. For example, embodiments may be provided in which the fixed gripping element ("anvil") 220 and the movable gripping element 212 act on the release wire 802 when the guide arm 216 engages the bottom of the guide track 120 instead of the top. Additionally, the guiding function provided by the guide track 120 may be provided by a raised wall or rib on the interior surface of the housing 100. Each guide arm 216 rides along the raised wall or rib.

[0031] Variations in the actuator can also be achieved by other mechanisms, for example a one-way rotating spool can be used, in which case a rotating dial can be provided for actuation by the user, such a device can allow retraction of the release wire by rotating in one direction and sliding in the opposite direction, as is understood from a ratcheting socket wrench, for example.

[0032] 8-11 show retraction device 10 in combination with an implant assembly 900 that is releasably coupled to a deployment tool (such as sheath 800) by an interlocking loop coupling system. Implant assembly 900 can include an implant device 901 (such as a vascular occluder as shown) and an implant loop 904 that can be attached to implant device 901 by a crimp portion 906 at a proximal end of implant device 901.

[0033] 8 and 9 show the interlocking loop coupling system in a non-detached state, i.e., when the implant assembly 900 is coupled to a deployment tool (eg, sheath 800) during deployment of the implant assembly at a target vascular site. FIG. 8 illustrates a retraction device 10 extending proximally from the proximal end of a sheath 800 and having a distal end engaging a proximal portion of a release wire 802 extending distally from the distal end of the sheath 800, as shown in FIG. With continued reference to FIG. 9, a tool loop 804 is attached to the distal end of a sheath 800 that contains a release wire 802 such that the tool loop 804 can be placed through or overlapping the implant loop 904. A distal end or portion of the release wire 802 extends through the tool loop 804 and the implant loop 904, thereby releasably connecting the loops 804,904. Thus, placement of the release wire 802 through the loops 804, 904 releasably couples the implant assembly 900 to the deployment tool (sheath) 800 and prevents separation thereof. In some embodiments, the crimp portion 906 can have a recess for receiving a distal end of the release wire 802 when the tool loop 804 and the implant loop 904 are coupled together as an interlocking loop. Alternatively, the implant loop 904 may be disposed inside the tool loop 804, or the implant loop 904 and the tool loop 804 may be assembled in a nested manner without either loop intersecting the other.

[0034] In aspects of the implant assembly 900, the implant loop 904 may be a loop that extends only into the crimped portion 906 where the implant loop 904 is secured to the implant 901 by crimping, welding, adhesive, or other suitable methods. In this manner, the amount of material required for the implant loop 904 may be reduced and the implant loop 904 may be independently adjusted depending on the implant technique. While the exemplary embodiment uses a loop, alternative shapes may be used. For example, a braid, cable or wound loop, or a coil structure within the loop may be provided.

[0035] 10 and 11 show the interlocking loop coupling system in a separated state, ie, when the implant assembly 900 is released or separated from the sheath 800 after deployment. To remove the implant assembly, the release wire 802 is withdrawn (proximally) from both the tool loop 804 and the implant loop 904, for example by means of the retraction device 10 described above. The retraction device 10 (or functional equivalent) is then manipulated to retract the release wire 802 , thereby separating the implant loop 904 from the tool loop 804 . Because the implant loop 904 and the tool loop 804 are not tied to each other or mechanically connected to each other, they release from each other only in response to retraction of the release wire 802, thereby releasing or separating the implant assembly 900 from the sheath 800. Thus, once the implant assembly is positioned and deployed at the target vascular site, separation of the implant assembly is achieved without application of significant axial forces to the implant, thereby minimizing the possibility of migration or displacement of the implant from the target site.

[0036] Withdrawal of the release wire 802 from engagement with the tool loop 804 and implant loop 904, resulting in release of the implant, can be detected by a sensor (not shown) within the retraction device 10. This can provide confirmation to the user that detachment has occurred. The sensor may detect proximity or contact with the release wire 802 or an element connected to the release wire. The sensor may be in visual or physical contact with the user, or in mechanical or electrical communication with an indicator element visible to the user. For example, a small light or light emitting diode (LED) may be incorporated into the retraction device 10, connected to a power source and a sensor, to indicate movement of the release wire 802 sufficient to release the implant.

[0037] In some embodiments, as shown in Figures 13-15, the overcoil 808 may extend axially between the distal end of the sheath 800 and the proximal end of the implant assembly 900 (e.g., the crimped portion 906, etc.), thereby extending coaxially around the loops 804, 904 and the distal end of the release wire 802 that interconnects them. The overcoil 808 can be either a unifilar or multifilar helical coil made from metal, polymer, or composite materials. 13-15, an embodiment of the interlocking loop coupling system can include a tubular or annular stop 812 attached to the overcoil 808 proximally from the tool loop 804, and a tubular ferrule 810 attached to the release wire 802 proximally from the stop 812. The ferrule 810 and top 812 are configured to reduce the possibility of undesired movement of the release wire 802, as described below.

[0038] It may be advantageous to minimize tortuous motion of the release wire 802 and to avoid the release wire 802 extending beyond the distal end of the overcoil 808. In particular, it is advantageous to avoid loose ends of the release wire 802 extending away from the overcoil 808 or the implant assembly 900. Tortuous motion can occur, for example, when the implant assembly 900 encounters high friction in the delivery microcatheter. As friction increases as the user continues to press on the proximal end of the delivery device, the overcoil 808 may begin to compress. If the overcoil 808 compresses while the implant position is axially fixed, the distal end of the release wire 802 could potentially extend in an undesired direction. The release wire ferrule 810 and stop tube 812 help minimize undesired movement of the release wire 802 during movement of the delivery device and positioning of the implant assembly 900 at the target site. The ferrule 810 and stop 812 may be made of any suitable metallic or non-metallic material, such as, for example, stainless steel, a polymer, or a composite. The ferrule 810 may be attached to the release wire 802 by any suitable means, such as, for example, an adhesive, or by crimping, welding, soldering, or other suitable method. The ferrule 810 and stop 812 are internally dimensioned to allow the tool loop 804 and release wire 802 to move freely within the overcoil 808 . Stop 812 may be attached to the inner surface of overcoil 808 at one or more attachment points 814, such as by laser welding, sonic welding, adhesive, or other methods. A stop 812 distal to the ferrule 810 can thereby function as a stop to limit distal movement of the ferrule 810. When the ferrule 810 is attached to the release wire 802, the stop 812 thereby also functions as a stop to limit distal movement of the release wire 802 relative to the loops 804, 904.

[0039] The inner diameter of the stop 812 is advantageously sized to accommodate the tool loop 804 and release wire 802, but not to allow the ferrule 810 to pass freely through the stop 812. Thus, even under high friction scenarios, the ferrule 810 will press against the stop 812 and prevent further distal movement of the release wire 802 relative to the overcoil 808. Also, because the release wire 802 can pass freely, the stop 812 does not impede the reverse movement required for implant removal. Thus, the ferrule 810 is prevented from further distal advancement because its outer diameter does not fit the inner diameter of the stop 812.

[0040] 14 is a cross-sectional view taken along line AA of FIG. 13 and shows the placement of a ferrule 810 coaxially surrounding the release wire 802. The tool loop 804 may be adjacent the release wire ferrule 810 inside the overcoil 808. 15 is a cross-sectional view taken along line BB of FIG. 13 and shows the placement of stop 812 within overcoil 808. Both the tool loop 804 and the release wire 802 may be inside stop 812, i.e., stop 812 coaxially surrounds both the tool loop 804 and the release wire 802.

[0041] The implant connection / detachment system according to the presently disclosed subject matter may be operated / operated as follows:

[0042] A release wire is provided that is slidably disposed within the deployment tool having a proximal end and a distal end terminating in a first loop, the release wire having a proximal end that extends proximally a short distance from the proximal end of the deployment tool and a distal end that passes through the first loop and the second loop at the proximal end of the implant device to releasably couple the implant device to the distal end of the deployment tool. The proximal end of the deployment tool is introduced into the distal opening of the release wire retraction device and secured within the retraction device with the proximal end of the release wire extending proximally from the proximal end of the deployment tool. A retraction device is actuated / manipulated to (1) grasp the proximal end of the release wire, (2) pull the release wire proximally through the deployment tool and withdraw the release wire from the first and second loops, thereby separating the implant device from the deployment tool, and (3) decouple the release wire after the release wire has been moved proximally.

[0043] In another aspect, a method according to the present disclosure comprises: (1) providing a deployment tool having a first loop attached to a distal end thereof; (2) providing an implant device having a second loop on a proximal end thereof; (3) passing a release wire axially through the deployment tool such that a distal end of the release wire passes through the first and second loops to releasably couple the implant device to the deployment tool and a portion of the release wire is exposed at a proximal end of the deployment tool; (4) Grasping the exposed portion of the release wire; and (5) pulling the release wire proximally through the deployment tool until the distal end of the release wire is withdrawn from the first and second loops and the implant device is separated from the deployment tool. may include:

[0044] While exemplary embodiments of the subject matter of the present disclosure have been particularly described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. It should therefore be understood that the retraction devices and interlocking loop coupling systems, their respective components, and associated methods as disclosed herein may be embodied other than as described herein. It will also be understood that the above-described interlocking loop coupling systems are well suited for use with the release wire retraction devices previously described. It is believed, therefore, that there are many applications and situations in which they are used together in implant device deployment systems and methods in which an implant device is deployed by a release wire, however, in other applications and situations it may be advantageous to use the interlocking loop coupling system described above with other types of retraction devices or to use the retraction devices described above with other types of implant / release wire coupling systems and arrangements.

Claims

1. 1. A device for retracting a release wire having a distal end that releasably couples a vascular implant device to a distal end of a deployment tool introduced into a blood vessel, the deployment tool having a proximal portion at which a proximal portion of the release wire is exposed; a housing having a distal opening configured to receive a proximal portion of the deployment tool, the proximal portion of the release wire being exposed; a guide assembly axially movable within the housing between a distal position and a proximal position; a spring engaged with the guide assembly and axially mounted within the housing to bias the guide assembly toward the distal position; Equipped with the guide assembly includes a proximal end surface and a spring support extending proximally from the proximal end surface, one end of the spring surrounding the spring support and seated against the proximal end surface of the guide assembly; The guide assembly includes: A first gripping element; and A second gripping element; Equipped with movement of the guide assembly between the distal position and the proximal position moves the second gripping element relative to the first gripping element between a first position configured to release from the exposed portion of the release wire when the guide assembly is in the distal position and the proximal position, and a second position configured to engage the exposed portion of the release wire when the guide assembly is in an intermediate position between the distal position and the proximal position, whereby movement of the guide assembly from the intermediate position to the proximal position is operable to move the release wire proximally within the housing with the second gripping element in the second position; the first gripping element is at a fixed position within the guide assembly and the second gripping element is pivotally attached to the guide assembly, whereby the second gripping element is moved between the first position and the second position by pivoting the second gripping element relative to the first gripping element within the guide assembly; device.

2. the guide assembly includes a lever having a first end at which the second gripping element is disposed and a second end movably seated in a guide path defined in the housing; the guide path is configured to pivot the lever to move the second gripping element between the second position and the first position when the guide assembly is moved between the distal position and the proximal position. The device of claim 1 .

3. an actuator having an outer portion configured for distal and proximal manipulation by a user and an inner portion operatively connected to the guide assembly for moving the guide assembly between the distal and proximal positions.

3. A device according to claim 1 or 2.

4. The guide path is configured as a closed loop. The device of claim 2.

5. The second end of the lever is configured as a guide arm movably engaged with the guide path. The device of claim 2.

6. The guide path is defined by a track in the housing. The device of claim 2.

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