Patent Application
20120203322
This disclosure relates generally to a mechanism for the deployment of a medical device within a patient. More specifically, this disclosure relates to a delivery assembly for a medical device and a method of mechanically releasing or detaching said device at a targeted vascular site.
A standard procedure used in the treatment of endovascular diseases is the placement of medical devices, such as embolic coils, stents, and dilation balloons, among others, at a desired or targeted site within a patient. The delivery of such a medical device have typically been accomplished by a variety of means, including the use of a catheter in which a pusher forces the device through the catheter to be deployed at the targeted site. These medical devices usually have a contracted shape that allows them to pass through the lumen of the catheter and an expanded shape that occurs after being deployed to the targeted site, such as an aneurysm.
One example, of such a medical device is an embolic or occlusive device that is placed within the vasculature of the human body, to filter the flow of blood through a vessel in the vasculature or to block the flow of blood within a defect in the vessel, such as an aneurysm. One widely accepted occlusive device is a helical wire coil whose coil windings are sized to engage the wall of the vessel. In this case, a catheter is first placed at or near the targeted site within the vessel. This catheter may be guided to the targeted site through the use of guide wires or the like. Once the distal end of the catheter has reached the site, one or more helical wire coils are placed into the proximal end of the catheter and advanced through the catheter using the pusher. Once the coil reaches the distal end of the catheter, the pusher discharges it from the catheter.
Despite the technological advancement in the field of delivering such occlusive devices to a target site, problems still exist with many of the current means of deployment. These problems include the ease of positioning and repositioning the helical wire coil before detachment from the catheter, the accuracy in maneuvering the coil into position at the target site, and the duration of time necessary to deploy the coil, to name a few. The inaccurate placement of the coil can be problematic because once the coil has left the catheter, it is difficult to reposition or retrieve the coil. In addition, the use of a pusher to force the coil out of the catheter can result in localized damage to the vasculature, such as thermal damage to the tissue surrounding the distal end of the catheter.
Accordingly, there exists a desire to provide improvements in the mechanism used to detachably deploy a medical device at a targeted location in the vasculature of a patient. More particularly, there exists a desire for the continued development of a coupling mechanism that securely holds the medical device, thereby, allowing it to be effectively maneuvered throughout the deployment process, while also allowing said medical device to be easily and reliably detached once it is properly located at the target site. A mechanism that is adaptable for use with a wide variety of medical devices would be advantageous.
In satisfying the above need, as well as overcoming the enumerated drawbacks and other limitations of the related art, the present disclosure generally provides a medical device assembly having a quick release mechanism for use by an operator in deploying a medical device at a targeted site in a body vessel. The medical device assembly comprising a quick release mechanism and a medical device reversibly attached thereto.
According to one aspect of the present disclosure, the quick release mechanism comprises a pusher element having a distal end, the pusher element including an inner core wire and an outer coil. The inner core wire and outer coil are coupled together at the distal end of the pusher element. The outer coil, which is also defined by a proximal section and a distal section, has an enlarged overall thickness in the distal section.
According to another aspect of the present disclosure, the medical device has a proximal part and a distal part with the proximal part including an opening that is sized to receive and to detachably engage the distal section of the outer coil. Movement of the outer coil opposite to the movement of the inner core wire reduces the thickness of the outer coil in the distal section, thereby, allowing the medical device to detach from the wire guide for deployment in the body vessel.
According to yet another aspect of the present disclosure, a method is provided for use by an operator in deploying a medical device at a targeted site in a body vessel. The method generally comprises the steps of introducing a catheter having a distal end and a proximal end into a body vessel. The distal end of the catheter being positioned proximate to a targeted site within the vessel. Then a medical device assembly is placed into the proximal end of the catheter. The medical device assembly comprises a medical device and a quick release mechanism as described herein having an engaged position in which the medical device and quick release mechanism are engaged and a detached position in which the medical device and quick release mechanism are not engaged. The medical device assembly is then moved through the catheter to the targeted site in the vessel while the quick release mechanism is in the engaged position. The operator may cause the quick release mechanism to move from the engaged position to the detached position, thereby, deploying the medical device at the targeted site in the vessel. Optionally, the operator may further position the medical device proximate to the targeted site after the device exits the catheter prior to causing the quick release mechanism to transition to the detached state.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is in no way intended to limit the present disclosure or its application or uses. It should be understood that throughout the description and drawings, corresponding reference numerals indicate like or corresponding parts and features.
The present disclosure generally provides a quick release mechanism for the deployment of a medical device at a targeted site in the vasculature of a patient, as well as a method of using said mechanism. The quick release mechanism basically comprises a pusher element having a wire coiled around the distal end of an inner core wire. The coiled wire has a proximal and distal section and is capable of interacting with a medical device to either hold or release said device in an engaged or detached position, respectively. The quick release mechanism has an engaged position in which the distal section of the coiled wire makes contact with the inner wall of an opening in the medical device to securely hold such device during deployment. The medical device may be attached proximate to the distal end of the coiled wire during the manufacturing process or by the attending operator prior to performing the deployment procedure by placing the distal section of the coiled wire into the opening in the medical device such that the medical device is releasably held by quick release mechanism. In use, the coiled wire, with the medical device attached, is advanced by the pusher element through a catheter to a target vascular site in a patient. Upon exiting the distal end of the catheter, the quick release mechanism is made to undergo a transition to a detached position, in which the coiled wire no longer engages the medical device, thereby, causing the medical device to be released or deployed. The pusher element can then be withdrawn, leaving the medical device in the desired position. Thus, the quick release mechanism of the present disclosure does not automatically release the medical device when it is extruded from the catheter, but rather, requires operator action to switch the mechanism from the coupled or engaged position to its detached or unengaged position.
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The medical device assembly 2 may comprise any metal, metal alloy, and/or polymeric materials known to one skilled-in-the-art. According to one aspect of the present disclosure, the quick release mechanism 1 and the medical device 25 that make up the medical device assembly 2 may comprise a super-elastic metal alloy, such as Nitinol, thereby, allowing for extended durability and flexibility. However, one skilled-in-the-art will understand that stainless steel or other metals and metal alloys may also be used with exceeding the scope of this disclosure. According to another aspect of this disclosure, at least a portion of the medical device assembly 2 may optionally have one or more surface treatments applied thereto, including but not limited to coatings, machining, and texturing.
The quick release mechanism 1 has two positions relative to the medical device 25. These positions are, namely, an engaged position and a detached position. In the engaged position, the quick release mechanism 1 engages the medical device and allows the pusher element 3 to move the quick release mechanism 1 and medical device 25 together as a medical device assembly 2, even after the medical device 25 is extruded from the end of the delivery catheter. In the detached position, the quick release mechanism 1 does not engage the medical device 25 and the medical device 25 is released or deployed at the selected target site. The medical device assembly 2 is designed such that the default position for the quick release mechanism 1 is the engaged position.
The switching between the engaged and detached positions is controlled by an operator, such as a physician or surgeon, through the manipulation of the inner core wire 5 and outer coil 10 of the pusher element 3. The movement of the inner core wire 5 in a distal direction along with movement of the outer coil 10 in a proximal direction relative to the vasculature of the patient causes the quick release mechanism 1 to switch from its engaged position to the detached position.
The quick release mechanism 1 as described herein can be adapted to be used with a variety of medical devices 25, including, but not limited to, embolic protection devices, occlusive devices, stents, and dilation balloons, among others. The medical device 25 may comprise any structure known to one skilled-in-the-art, including for example, occlusive devices of tubular structures, having braids, coils, a combination of braids and coils, or the like. The occlusive device may change shape during deployment, such as changing from a collapsed configuration to an expanded configuration. One example, among many examples, of a medical device 25 used with the quick release mechanism 1 of the present disclosure is a Nester® embolization coil (Cook Medical Incorporated, Bloomington, Ind.).
The delivery catheter used to deliver the medical device assembly 2 may be made of any material known to one skilled-in-the-art. Such material may include but not be limited a polyimide, polyether amide, nylon, polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), and mixtures or copolymers thereof. In its basic form, the catheter is a hollow elongated tube sized to receive the medical device assembly 2. The length of the delivery catheter may be any length necessary or desired to deploy the medical device 25 at the targeted site in the vasculature of a patient.
Another objective of the present disclosure is to provide a method of deploying a medical device 25 at a targeted site in the vasculature of a patient. This method generally comprises the steps of introducing the medical device assembly 2 described herein into the vasculature of the patient, wherein the quick release mechanism 1 is in its engaged position with the medical device 25; and then switching the quick release mechanism 1 to its detached position, thereby, deploying the medical device 25 at the targeted or desired site.
The present disclosure provides a quick release mechanism 1 that securely holds medical device 25 during the deployment of the medical device 25. The quick release mechanism 1 also allows for the easy and reliable detachment of the medical device 25 once the device 25 is properly positioned proximate to the targeted site. The quick release mechanism 1 of the present disclosure provides the operator (e.g., physician) with improved control over the medical device 25 during its deployment, and allows the operator to position and even reposition the medical device 25 at the targeted site before detachment. One skilled-in-the-art will understand that the quick release mechanism 1 of the present disclosure is readily adaptable for use with a wide variety of medical devices.
The foregoing description of various embodiments 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 embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.
