The present invention relates generally to systems and methods for implanting intravascular devices, and more specifically to manual systems and methods for mechanically releasing, detaching or otherwise deploying devices within a body lumen.
Numerous intravascular implant devices are well known in the field. Many are deployed mechanically, via systems that combine one or more catheters and wires for delivery. Examples of implants that may be delivered mechanically include embolic coils and other elements, stents, grafts, drug delivery implants, and the like. Some obstetric and gastrointestinal implants may also be implanted endolumenally via similar means. Devices that may be released or deployed by mechanical means vary greatly in design, but may employ a similar delivery catheter and wire system. Many such catheter-based delivery systems include a wire for retention of the implant in the catheter until the time for release of the device. These systems are then actuated by retracting or pulling the wire relative to the catheter. Such a wire is referred to herein as a “pull wire”. Examples of implants delivered via catheter and released via a pull wire are described in more detail in U.S. patent application Ser. No. 12/498,752, which is incorporated by reference as if set forth herein in its entirety.
Precise control of the timing of deployment of the implant is crucial for the successful treatment of vascular and luminal abnormalities. Premature release of an implant can lead to injury and death. The timing of deployment of the implant is under the control of an operator who will retract the pull to release the implant from the distal end of the catheter. The force applied and speed of action will vary among operators, and a single operator may apply force inconsistently.
Because of the foregoing needs, it is an object of the invention to confer consistent force and speed of release in deployment of a delivery system. It is a further object of the invention to achieve reliable and consistent delivery and deployment of an implant released utilizing a pull wire system. At least some of these objectives will be met by the inventions set forth below.
An actuation system according to the present invention is intended for use with an implant delivery system that employs a catheter and a pull wire for release of the implant. In a typical procedure utilizing the invention, an implant is loaded into the distal end of a catheter or comparable implant tool. The pull wire is disposed through the length of the catheter with a distal end retaining the implant near the distal end of the catheter and a proximal end remaining in control of the operator. The catheter is then introduced, for example, into the femoral artery and navigated through the vascular system under fluoroscopic visualization. The distal end of the catheter is positioned at the proposed treatment site within the vasculature or other luminal structure of a subject. The treatment site may be, for example, an aneurysm, an arterio-venous malformation, an occlusion, or other defect. Once positioned, the pull wire is retracted relative to the catheter, typically manually, and the implant is released from the catheter distal end and to the particular treatment site. Once released from the catheter, the implant may for example assume a secondary shape selected to optimize treatment, such as filling of an aneurysm cavity, or alternatively, re-establishing patency of a vessel. In some cases, multiple implants may be introduced to a single treatment site, optionally using the same actuation system with multiple delivery catheters.
In a first aspect of the present invention, a handle for retracting a pull wire disposed in a catheter body comprises a shell having a distal end, a proximal end, and a receptacle at the distal end for receiving a proximal end of the catheter body. A trigger is slidably mounted on an exterior of the shell, and a slider carrying a tripping element is disposed within the shell and coupled to move with the trigger. A shuttle is also slidably disposed within the shell and is coupled to the slider by a first energy storage member, such as an elongate coil spring, where the shuttle carries a wire grabber at its distal end and has a latch member releasably engageable with a stop member fixed to the shell, typically on an inside surface of the shell. Proximal retraction of the trigger by a physician or the user draws the slider proximally within the handle, storing potential energy in the first energy storage member. The stop member immobilizes the shuttle until the tripping element on the slider engages and releases the latch from the stop element, thus allowing the shuttle to be abruptly pulled proximally by release of energy from the first energy storage member, e.g., contraction of the coil springs. In this way, the physician or other user can smoothly pull back the trigger to store sufficient energy to provide the rapid retraction of the pull wire which is desired.
Usually, the slider will be further adapted to open the wire grabber to release the pull wire when the trigger is fully returned to its initial position. Such decoupling of the pull wire is a safety feature which reduces the risk of inadvertently moving the pull wire to dislodge the implant or otherwise have a deleterious effect. Such automatic release of the wire grabber also resets the handle for use with another catheter and pull wire.
In a further preferred aspect, initial proximal refraction of the trigger will close the wire grabber to engage the pull wire. Thus, the physician or other user need only insert a proximal end of the catheter into the receptacle at the end of the shell to position the pull wire in the grabber. Engagement of the pull wire then occurs automatically as the trigger is initially retracted.
The shuttle is initially immobilized relative to the handle by a locking or latching mechanism. The locking mechanism typically comprises a lever pivotally mounted on the shuttle and having a surface which is engaged by a wedge on the slider to open the latch to release the stop when the trigger is fully retracted in the proximal direction.
The first energy storage member typically comprises an elastic extension member, typically an elongate coil spring, mounted between the slider and the shuttle so that it elongates as the trigger is proximally retracted. The handle assembly will typically include a second energy storage member coupled between the slider and the shell such that proximal refraction of the trigger stores potential energy in the second energy storage member to return the slider to its distal most position when the trigger is released. Usually, the second energy storage member will be a coil compression spring.
In a second aspect of the present invention, a method for retracting a pull wire in a catheter, typically to release an implant, comprises mating a proximal end of the catheter with a handle. A trigger on the handle is then proximally retracted to proximally translate a slider in the handle to perform the following steps in sequence. First, a grabber disposed on a shuttle is caused to capture a proximal end of the pull wire. Second, potential energy is stored in a first energy storage device coupled between the slider and the shuttle as the slider is proximally retracted. Third, the shuttle is released so that it can be pulled proximally by the energy storage device in order to retract the pull wire relative to the catheter.
Typically, mating the catheter to the handle comprises aligning a proximal end of the catheter body in a conical receptacle at a distal end of the handle so that the pull wire extends through an opening at the apex of the conical receptacle to pass into the handle. The grabber will typically have a spring-loaded, pivotally mounted lever which closes on the pull wire as a wedge on the slider retracts relative to the shuttle. Thus the pull wire which extends into the handle can be automatically grasped as a trigger is retracted to move a slider relative to the shuttle.
Usually, the shuttle is initially held in place by a latch on the shuttle which engages a stop on the handle. The shuttle is subsequently released by a trip on the slider which engages and dislodges the latch when the slider is retracted proximally by a pre-selected distance, where the distance is selected to store an appropriate amount of energy in the energy storage device. After release of the pull wire, the trigger may be released so that the slider and shuttle return to their distal-most position and the grabber releases the wire. Typically, the slider and shuttle are caused to return to their distal-most position by the release of energy from a second energy storage device disposed between the slider and the handle, where the second energy storage device had stored potential energy as the trigger was initially retracted.
Referring to
In order to use system 10, an implant is loaded into the catheter 19 (for example the coil delivery catheter described in commonly owned, copending application Ser. No. 12/498,752, previously incorporated herein by reference) and carried until the implant and the distal end of catheter 19 are properly positioned in a blood vessel or other body lumen for deployment. The pull wire 16, extends through catheter body 18, and the proximal end of the pull wire is loaded into the distal end of handle 20 after positioning a proximal end of the catheter body 18 at the apex of a funnel 12 formed in a distal end of the handle 20. Although the term “wire” is used herein, it will be understood that any elongated filament of suitable mechanical properties and structure is included in the term.
While other configurations are within the scope of the invention, handle 20 advantageously includes a finger groove 21 defined by the exterior of handle 20. Also disposed on the exterior of handle 20 is a thumb grip 34, which is axially movable along the exterior of handle 20 via a channel or comparable structure 34′ (
Handle 20 may be manufactured from a suitable medical grade plastic, such as Santoprene medical grade Thermoplastic Vulcanizate available from ExxonMobil Chemical, or acrylonitrile butadiene styrene (ABS) available from Lustran. Suitable materials include materials that may be sterilized in ethylene oxide or radiation, or in an autoclave. Further, desirable materials include those that are injection moldable and recyclable. The external surfaces of handle 20 are preferably smooth and non-abrasive. The internal components of handle 20 may be manufactured from polycarbonate and silicone available from RTP Co. or similar materials and may additionally include stainless steel, rubber or other suitable materials. Manual actuation system 10 may include additional elements, materials and coatings for securing the components and for smooth inter-operative engagement of the components.
An overview of the operation of handle 20 is as follows.
A more detailed description of these separate phases of operation of system 10, with reference again to
The features of the primary mechanisms can be described as follows, though it will be understood that other configurations are possible according to the invention. The “at rest” and “grasping” positions result from interaction between parts of grabber 24 and slider 28. As shown in
An initial, slight retraction of thumb grip 34 (in the direction of the proximal direction indicated by the arrow on
Following grasping of the pull wire, further retraction of thumb grip 34 serves to “prime” system 10 for launch of shuttle 36. During the “priming” phase, grabber 24 remains stationary, along with pull wire 16 and shuttle 36. Shuttle 36 (now stationary) is linked to slider 28 (which is being retracted) via extension spring 35. During refraction of slider 28, extension spring 35 is progressively stretched, and potential “retraction” energy within extension spring 35 is increasing. Shuttle 36 remains stationary because coupled by a button 52 to a stop 48 formed on or attached to an inner surface of the housing 20. Priming of the system continues as thumb grip 34 is retracted proximally until a trip 38 on a lower distal portion of slider 28 engages and depresses the button 52 to release the stop 48, allowing the shuttle 36 to be drawn proximally by spring 35. (illustrated in
Button 52 extends from latch member 50, which is cut within a sidewall or otherwise disposed upon shuttle 36. When system 10 is at rest, and during the priming phase, button 52 rests against stop 48. With respect to slider 28, a trip 38 is defined by the proximal end of wedge 26. Trip 38, as a matter of course, travels proximally with slider 28 during retraction of slider 28. When slider 28 is retracted to the point that trip 38 reaches button 52, trip 38 acts to depress button 52 via latch member 50, thereby releasing button 52 from its resting position against stop 48. (See
Referring back to the “priming” phase, during extension of spring 35, a compression spring 37 is increasingly compressed, and compressive force increases within compression spring 37. Following the launching phase, the user may then release thumb grip 34. Upon release of thumb grip 34, the tension stored in compression spring 37 acts to return slider 28 and shuttle 36 to a neutral position, shown in
While the invention may be modified and alternative forms may be used, specific embodiments of the invention have been illustrated and described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed. The invention and following claims are intended to cover all modifications and equivalents falling within the spirit and scope of the invention.
This application is a continuation of U.S. patent application Ser. No. 14/542,001 (Attorney Docket No. 41507-710.301), filed Nov. 14, 2014, now U.S. Pat. No. ______, which is a continuation of U.S. patent application Ser. No. 12/888,137 (Attorney Docket No. 41507-710.201), filed Se. 22, 2010, now U.S. Pat. No. 8,911,487, which claims priority to Provisional Application No. 61/244,785, (Attorney Docket No. 41507-710.101), filed Sep. 22, 2009, the disclosures of which are incorporated herein by reference in their entirety.
Number | Date | Country | |
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61244785 | Sep 2009 | US |
Number | Date | Country | |
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Parent | 14542001 | Nov 2014 | US |
Child | 15451201 | US | |
Parent | 12888137 | Sep 2010 | US |
Child | 14542001 | US |