CN117157020A

CN117157020A - Apparatus and method for implantation of arteriovenous grafts

Info

Publication number: CN117157020A
Application number: CN202180096403.9A
Authority: CN
Inventors: S·M·盖奇; J·卢卡斯; C·尼科尔斯; J·奈特; J·切欧索内; P·罗森; S·布什; B·沃尔什
Original assignee: Innavask Medical Co ltd
Current assignee: Innavask Medical Co ltd
Priority date: 2021-03-26
Filing date: 2021-12-30
Publication date: 2023-12-01
Also published as: CN117136082A

Abstract

An apparatus for delivering a vascular arteriovenous graft includes a tubular sleeve (44) defining a lumen adapted to be slidably positioned over a tunneling instrument (44). Once the tunneling instrument has been advanced to the desired subcutaneous anatomical location, the shaft is removed while the sleeve remains in the tissue. The sleeve has a linear slit (58) extending from the proximal end to a point intermediate the length of the sleeve. The lumen receives the distal end of the graft and at least a portion of the cannula chamber such that the end of the sleeve gradually expands along the slit to provide an enlarged diameter for receiving the cannula chamber. Longitudinal forces acting on the sleeve during removal of the sleeve from tissue secure the graft in the sleeve by radial compression of the sleeve to pull the graft and sleeve through the tunnel and deploy the vascular graft.

Description

Apparatus and method for implantation of arteriovenous grafts

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application No. 63/166794 and U.S. provisional application No. 63/166790, both filed on 3/26 of 2021, the disclosures of which are incorporated herein by reference in their entirety.

Background

Devices and methods for implanting an arteriovenous graft are described, and more particularly devices and methods for forming a subcutaneous anatomical tunnel for implanting an arteriovenous graft using a tunneling instrument, including delivering the graft using a removable sleeve encasing the tunneling instrument.

Vascular arteriovenous grafts are tubular devices that are adapted to be implanted in the body to redirect blood flow between blood vessels. Surgical implantation of an arteriovenous graft requires placement of the graft within subcutaneous tissue. The initial step in the implantation procedure is to create a subcutaneous anatomic path or "tunnel" between the anastomotic sites for the passage of an arteriovenous graft, which path is commonly referred to as a graft tunnel. This is the necessary surgical step in all peripheral vascular surgical procedures for peripheral, vascular access and dissection of the outer graft site. An arteriovenous graft is positioned in a tunnel within body tissue for securing the graft to an existing peripheral vessel to form a bypass around the vessel, or a portion thereof, or a connection of an artery and vein to form an arteriovenous shunt. Vascular grafts may also connect arteries to arteries.

Conventional tunneling devices include an elongated rigid rod having a handle on a proximal end and a bullet-shaped tip at a distal end. The size and shape of the shaft may be different and may have a straight, curved or semi-circular axis, which allows for a variety of implant placement positions and orientations. During the tunneling procedure, a first proximal incision and a second distal incision are made at selected anastomosis regions. The tip at the distal end of the tunneling device is inserted into the proximal incision. The tip of the tunneling device is then forced through the subcutaneous tissue, thereby creating a path between the incisions through the blunt incision until the tip protrudes from the distal incision. Once the tip is exposed, the proximal end of the arteriovenous graft is tied to the distal or tip of the tunneling device with a sterile suture. The tunneling instrument and attached arteriovenous graft are then pulled proximally along a path through the recently cut graft tunnel until the proximal end of the arteriovenous graft extends out of the proximal incision. When the arteriovenous graft is properly positioned, the graft is severed from the distal end of the tunneling instrument, thereby removing a portion of the graft. An anastomosis is formed between the end of the graft and the blood vessel surrounding the vasculature area to be bypassed, and the incision is closed.

The step of pulling the tunneling instrument and attached arteriovenous graft through the graft tunnel can require significant force. The force required depends on a number of factors, including the relative dimensions of the graft tunnel and the graft and the material of the graft. Conventional delivery systems for arteriovenous grafts and other implantable devices are sometimes covered by a retaining sleeve that reduces friction through the subcutaneous tissue. After implantation, the sleeve is removed by pulling back on the device or rolling the sleeve to retract the sleeve. While rolling the sleeve during retraction reduces the necessary pulling force as compared to retracting the sleeve by sliding the sleeve over the device, significant force may still be required to retract the sleeve after the arteriovenous graft is implanted.

For the foregoing reasons, there is a need for an apparatus and method for implanting an arteriovenous graft that minimizes the force required to deliver the graft. The new device in the form of a sleeve should help define and support the length of the anatomical tunnel formed by the tunneling device. The sleeve should be able to be withdrawn in a reliable manner with low tension to minimize problems associated with excessive axial forces on the sleeve during retraction. The new devices and methods should also be capable of implantation of any type of vascular graft, including but not limited to ePTFE and natural tissue grafts.

Disclosure of Invention

An apparatus for subcutaneous delivery of a vascular arteriovenous graft in tissue of a patient is provided, the apparatus including a cannula chamber and having proximal and distal ends and a length extending between the proximal and distal ends along a longitudinal axis. The device uses a rigid tunneling instrument that includes an elongate shaft having a handle at a proximal end of the shaft and a removable tip at a distal end of the shaft for forming a passageway in subcutaneous tissue. The subcutaneous delivery device includes an elongate tubular sleeve having a length and defining a lumen, the sleeve adapted to be slidably positioned over at least a portion of a shaft of a tunneling instrument between a handle and a tip. Once the tunneling instrument has been advanced to the desired subcutaneous anatomical location, the shaft is selectively removed from the sleeve while the sleeve remains positioned at the desired anatomical location. The sleeve has a linear slit extending along the length of the sleeve from the proximal end to a point midway along the length of the sleeve. The lumen formed at the proximal end of the sleeve is adapted to receive the distal end of the graft and at least a portion of the cannula chamber such that the proximal portion of the sleeve gradually expands along the slit to provide an enlarged diameter for receiving the cannula chamber. Application of a longitudinal force from the distal end of the sleeve to the sleeve is effective to cause movement of the sleeve in a distal direction during removal of the sleeve from tissue such that the graft is secured in the sleeve by radial compression of the sleeve for pulling the graft and sleeve through the tunnel, deploying the vascular graft.

In one aspect, the sleeve is adapted to receive substantially the entire length of the shaft between the handle and the tip. In another aspect, the sleeve tapers uniformly from the proximal end to the distal end such that the distal end has a diameter that decreases from the proximal end.

In one embodiment, the sleeve includes an enlarged diameter portion adjacent the proximal end and adapted to receive the cannula chamber.

An apparatus for subcutaneously implanting a vascular arteriovenous graft in tissue of a patient is also provided, the apparatus comprising a cannula chamber and having a proximal end and a distal end and a length extending between the proximal end and the distal end along a longitudinal axis. The subcutaneous implant device includes a rigid tunneling instrument for creating a path in subcutaneous tissue. The tunneling instrument includes an elongate shaft having a handle at a proximal end of the shaft and a removable tip at a distal end of the shaft. The elongate tubular sleeve has a length and defines an inner lumen. The linear slit extends along the length of the sleeve from the proximal end to a point intermediate the length of the sleeve. The sleeve is configured to be slidably positioned over at least a portion of the shaft of the tunneling instrument between the handle and the tip. Once the tunneling instrument has been advanced to the desired subcutaneous anatomical location, the shaft is selectively removed from the sleeve while the sleeve remains positioned at the anatomical location. The lumen is adapted to receive at least a portion of the distal end of the graft and the cannula chamber via the proximal end of the sleeve such that the proximal end portion of the sleeve gradually expands along the slit to provide an enlarged diameter for receiving the cannula chamber. For removing the sleeve from tissue, applying a longitudinal force to the sleeve from the distal end of the sleeve effectively causes movement of the sleeve in a distal direction such that the arteriovenous graft is secured in the sleeve by radially compressing the tissue surrounding the sleeve. The arteriovenous graft and sleeve are pulled through the tunnel, causing the vascular graft to expand.

One feature of the sleeve includes a wall at the proximal end having an axial opening for receiving the tip of the tunneling instrument for connection of the sleeve to the tunneling instrument. A clamp comprising a pin, wherein the shaft has a bore adjacent the end defining an axial passage for receiving the pin.

A system for subcutaneous delivery of a medical device into a patient is provided. The subcutaneous delivery system includes a tunneling instrument comprising: a shaft having a proximal end and a distal end; a vascular graft having a length, a distal end, a proximal end, an outer surface, and a longitudinal axis; and a sleeve having a length and positioned over a majority of the outer surface of the shaft. The sleeve is configured to apply radial pressure on the cannula chamber when a longitudinal force is applied to the sleeve in a distal direction for implantation of the vascular graft to cause movement of the sleeve in the distal direction during removal of the sleeve.

One feature of the sleeve includes a wall at the proximal end having an axial opening for receiving the tip of the tunneling instrument for connection of the sleeve to the tunneling instrument.

In another embodiment, the subcutaneous delivery system may further comprise a clip comprising a pin, wherein the shaft has a hole adjacent the distal end defining an axial channel for receiving the pin for connecting the shaft to the sleeve for applying a pulling force in the proximal direction.

A method for subcutaneously implanting an arteriovenous graft into tissue of a subject is also provided. The arteriovenous graft includes a cannula lumen, a proximal end and a distal end, and a length extending between the proximal end and the distal end along a longitudinal axis. The method of implantation includes the step of cutting tissue of the subject in a first proximal position and a second distal position spaced apart from the first proximal position. A rigid tunneling instrument is provided that includes an elongate shaft having a handle at a proximal end of the shaft and a removable tip at a distal end of the shaft. The tip is removed and a tubular sleeve is disposed over at least a portion of the shaft between the tip and the handle, the sleeve having a slit extending along a length of the sleeve from the proximal end to a point intermediate the length of the sleeve. The distal end is secured to the distal end of the shaft and inserted into the first incision, and the user advances the instrument and sleeve subcutaneously along the path through the tissue until the distal end exits the second incision such that the distal end of the sleeve extends from the second incision and the proximal end of the sleeve extends from the first incision. The tip is removed prior to pulling the tunneling instrument proximally through the handle to remove the shaft from the sleeve in the tissue. The distal end of the graft is inserted into the proximal end of the sleeve until the cannula lumen at least partially enters the sleeve, causing the sleeve to expand along the slit to accommodate at least a portion of the lumen. The method comprises the following steps: the sleeve is pulled distally to withdraw the sleeve from the tissue while the proximal end of the sleeve is compressed by the severed tissue defining the tunnel, forcing the sleeve against the chamber to pull the graft through the tissue with the sleeve.

In one aspect, the method may further comprise the step of pulling the proximal end of the arteriovenous graft proximally to pull the cannulated chamber of the arteriovenous graft back into the tissue.

Drawings

For a more complete understanding of the apparatus and method for forming a subcutaneous anatomical tunnel, reference will now be made to the embodiments illustrated in the drawings and described below. In the drawings:

fig. 1 is a perspective view from the distal end of a tapered sleeve for use with a tunneling instrument for subcutaneously deploying an arteriovenous graft.

Fig. 2 is a perspective view from the proximal end of the sleeve shown in fig. 1.

Fig. 3 is a proximal end view of the sleeve shown in fig. 1.

Fig. 4 is a distal end view of the sleeve shown in fig. 1.

Fig. 5 is a top plan view of the sleeve shown in fig. 1.

Fig. 6 is a bottom plan view of the sleeve shown in fig. 1.

Fig. 7 is an exploded perspective view of an apparatus for forming a subcutaneous anatomic tunnel and delivering an arteriovenous graft.

Fig. 8 is a perspective view of the tunnel-forming and delivery device shown in fig. 7 in a state of tunneling using a sleeve on the tunneling instrument.

Fig. 9 is a close-up perspective view of the shaft of the tunneling instrument shown in fig. 7 inserted into the sleeve shown in fig. 7.

Fig. 10 is a perspective view showing a tunneling instrument covered by a sleeve as shown in fig. 8 and deployed in a portion of tissue and having ends extending from spaced apart incisions.

Fig. 11 is a perspective view as in fig. 10 with the tunneling instrument removed and showing the sleeve in tissue.

Fig. 12 is a perspective view as in fig. 11, showing an arteriovenous graft including a cannula chamber loaded into the proximal end of a sleeve.

Fig. 13 is a perspective view as in fig. 12, showing the proximal end of the sleeve exiting the tissue and the cannula lumen of the arteriovenous graft partially extending from the tissue.

Fig. 14 is a perspective view as in fig. 13, with only the arteriovenous graft held in the tissue, with both ends extending from the tissue at each incision.

Fig. 15 is a cutaway perspective view of the proximal end of another embodiment of a sleeve for use with a tunneling instrument.

Fig. 16 is a cutaway perspective view of the proximal end of a third embodiment of a sleeve for use with a tunneling instrument.

Fig. 17A and 17B are perspective views of a fourth embodiment of a sleeve for use with a tunneling instrument.

Fig. 18 is a perspective view of a mechanical fastening element for connecting a sleeve to the tunneling instrument shown in fig. 1.

Fig. 19 is a perspective view of a fifth embodiment of a sleeve for use with a tunneling instrument for delivering an arteriovenous graft having a cannula lumen.

Fig. 20A and 20B are perspective views of a sixth embodiment of a sleeve and tunneling instrument for delivering an arteriovenous graft.

Disclosure of Invention

Certain terminology is used herein for convenience only and is not to be taken as a limitation. For example, words such as "top," "bottom," "upper," "lower," "left," "right," "horizontal," "vertical," "upward" and "downward" merely describe the configuration shown in the figures. Indeed, the components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise. The words "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of the core and designated portions thereof. The terminology includes the words specifically mentioned above, derivatives thereof and words of similar import.

Referring now to the drawings, in which like reference numerals designate corresponding or similar elements throughout the several views, there is shown in fig. 1 an embodiment of an apparatus for forming a subcutaneous anatomical tunnel for implanting a vascular arteriovenous graft into a patient, and which is designated generally at 40. The tunnel forming and implanting apparatus 40 includes a tunneling instrument 42 (also referred to herein as a "tunneling device"), a tubular sleeve 44, and a vascular arteriovenous graft 46. Tunneling instrument 42 includes an elongated rigid shaft 48, a proximal handle 50 at one end of the shaft, and a removable distal tip 52 at the other end of the shaft. The tip 52 is generally bullet-shaped or otherwise has an oval or circular shape with a diameter that increases from the pointed distal end. During the tunneling procedure, shaft 48 and tip 52 are advanced through the subcutaneous tissue by applying an axial force in the distal direction on handle 50, with the tip helping to blunt the inherent tissue during the tunneling procedure. Shaft 50 and tip 52 may be constructed of stainless steel, but one of ordinary skill in the art will recognize that other materials may be suitable. One such example of an alternative material is a plastic, such as a hard plastic. A suitable tunneling instrument is the Kelly-Wick tunnel available from deluxe Bard corporation (CR Bard, inc.) of the Meng Kesi family of nano, south carolina.

An arteriovenous graft 46 suitable for use in the apparatus and method is described in U.S. patent No. 9,585,998, the contents of which are incorporated herein by reference in their entirety. The arteriovenous graft 46 includes a catheter 132 having a first end portion 134 and a second end portion 136. The first end portion 134 is configured to be connected at its end to a first blood vessel of a subject, such as an artery. The second end portion 136 is configured to be connected at its end to a second blood vessel of the subject, such as a vein. In this regard, blood flows through the conduit 132 from the first end portion 134 to the second end portion 136. At least one cannula chamber 140 is positioned between the first end portion 134 and the second end portion 136 of the catheter 132. Cannula chamber 132 extends through chamber 140. The cannula chamber 140 has an open front portion defining a cannula port configured to receive a dialysis needle therethrough. It should be appreciated that the tunnel-forming device can also be used with any vascular graft as well as natural tissue grafts or fistulae.

Referring to fig. 2-7, tubular sleeve 44 includes a hollow tube that is open at both proximal end 54 and distal end 56. In one embodiment, the diameter of the sleeve 44 tapers from the proximal end 54 to the distal end 56. The diameter of sleeve 44 at distal end 56 is less than the maximum diameter of tip 52. As shown in fig. 8, sleeve 44 engages tip 52 proximally and extends to handle 50 of tunneling instrument 42. The sleeve 44 is sized in diameter and length to be slidably positioned over at least a portion of the shaft 48 of the tunneling instrument 42 and to enclose at least a portion of the shaft 48 during the tunneling procedure. After tunneling of tissue, upon application of a pulling force on the handle 50 in a proximal direction along the longitudinal axis of the shaft 48, the tip 52 is removed and the shaft 48 is withdrawn from the sleeve 44. Due to the unrestricted and flexible nature of the surface of sleeve 44, sleeve 44 remains in the tissue and allows graft 46 to be inserted through the tunneled tissue path.

As best seen in fig. 6 and 7, the sleeve 44 has a linear slit 58 oriented along the longitudinal axis of the sleeve, the slit 58 extending from the open proximal end 54 to a location along the length of the sleeve 44. The slit 58 may be oriented generally linearly or helically (not shown) along the length of the sleeve 44. The slit 58 allows the sleeve 44 to expand at the slit when an arteriovenous graft is inserted into the proximal end 54 of the sleeve. In the illustrated embodiment, the sleeve 44 has a hole 60 at the end of the slit 58 to prevent tearing of the sleeve from the slit 58 as the sleeve expands. The length and shape of the slit 58 may vary. The shorter slit allows for receiving only a smaller area of the cannula chamber 140, which may reduce surface damage. The longer slit 58 allows for receiving a greater portion of the cannula chamber 140 to better grip the chamber 140 during delivery to reduce the risk of sleeve release before the graft 46 fully enters the anatomic tunnel. The slit 58 opening may also have a different shape. Fig. 15 shows the removal of material from the proximal end 54 of the sleeve 44 to form a triangular opening. Similarly, fig. 16 shows a slit 58 forming a rectilinear opening for receiving the cannula chamber 140. A plurality of slits (not shown) may also be used. The plurality of slits allow for the insertion of a larger cannula chamber 140 into the sleeve 44 and clamping by the sleeve 44. It should be appreciated that the slit 58 in the end of the sleeve 44 is not necessary when the sleeve is used for deployment of conventional and biological grafts. In this application, no slit is required, as the lumen is larger than the implant diameter. The implant may simply be slid into the sleeve 44 in the tissue and the sleeve 44 pulled out of the tissue leaving the implant behind.

The sleeve 44 may be constructed of any smooth, flexible, and compressed biocompatible material. Suitable materials may be porous, non-porous, permeable or impermeable. The sleeve material does not flex excessively so that the sleeve 44 can absorb the tension applied during tunneling and deployment of the graft 46. Examples of such materials include, but are not limited to, silk, silicone, fluoropolymers such as expanded polytetrafluoroethylene (ePTFE), high Density Polyethylene (HDPE), and other polymers such as polyester and polyimide. Suitable materials are available from Colorite corporation of Ridgefild, new Jersey. Various desired configurations can be achieved by varying the sleeve material and characteristics such as thickness and width. The sleeve 44 may be extruded. It should be appreciated that the sleeve 44 may have a coefficient of friction low enough that the sleeve may be removed from the anatomic tunnel by an axial pulling force on the sleeve.

In another embodiment, sleeve 44 has a "double wall" configuration. The double-walled sleeve is formed from a double-walled thin flexible compressible material closed at both ends. The inner portion or first wall of the sleeve 44 has a predetermined stiffness and extends radially over and along the sleeve from a location at the proximal end 54 of the sleeve 44 to the distal end 56 of the sleeve. An outer portion or second wall of the sleeve extends radially from the proximal end 54 of the sleeve 44 over the inner portion and axially along the inner portion to the distal end 56. The inner portion of double-walled sleeve 44 is less stiff than the outer portion, thereby providing a stiffer outer shell and a softer inner portion surrounding implant 46 to prevent damage during deployment.

The smooth outer surface of the sleeve material may allow the sleeve 44 to have a low coefficient of friction. The result is that the tunneling instrument 42 and sleeve 44 are easier to insert through tissue and have less trauma, less friction, less blunt cutting, and less resistance during placement. Because of the smoothness and low profile of sleeve 44 relative to shaft 48, the sleeve does not substantially increase the outer diameter of tunneling instrument 42.

The sleeve 44 can optionally be coated with a lubricious substance on the outer surface to provide a low coefficient of friction to assist insertion and movement of the sleeve 44 and associated tunneling instrument 42 through tissue while minimizing tissue resistance and trauma during insertion or during sleeve removal after implantation. This will minimize tissue resistance and tissue damage during insertion of the tunneling instrument 42 and sleeve 44 or during removal of the sleeve 44 during implantation of the graft 46. It should be understood that a variety of coatings may be used, including therapeutic agents for delivering therapeutic materials. Solid lubricants (i.e., graphite, wax, silicone), fluid lubricants (i.e., hydrocarbon oils, silicone oils), gels (i.e., hydrogels), or any other biocompatible material known in the art may be used. In one embodiment, the sleeve 44 may be coated or wetted prior to use. In another embodiment, applicants contemplate a kit comprising a sleeve 44 and a wetting agent for wetting the sleeve. In another embodiment, the kit includes a sleeve 44, an arteriovenous graft 46, and a wetting agent for wetting the sleeve.

In use, a first proximal incision 80 is first made through the patient's skin 78 into underlying subcutaneous tissue and a second distal incision 82 spaced apart from the first incision. The tip 52 at the distal end 53 of the tunneling instrument 42 is inserted into the first incision 80 along with the sleeve 44 on the shaft 48 and then forced horizontally through the subcutaneous tissue along the path until the tip exits the second incision 82 (fig. 10). Tip 52 is then removed by the surgeon and tunneling instrument 42 is pulled proximally from first incision 80 via handle 50 to remove shaft 48 from the tissue. The sleeve 44 remains within the body tissue. As shown in fig. 11, the ends 54, 56 of the sleeve 44 extend proximally and distally from first and second incisions 80, 82 external to the skin 78.

The distal portion 136 of the graft 46 is inserted into the proximal end 54 of the sleeve 44 until the cannula chamber 140 at least partially enters the sleeve 44 (fig. 12). The sleeve 44 allows the surgeon to easily push the vascular graft 46 into a lumen defined by the sleeve that is oversized compared to the outer diameter of the catheter 132 of the vascular graft 46. However, the sleeve 44 is configured such that the outer diameter of the cannula chamber 140 is greater than the inner diameter of the sleeve. The cannula chamber 140 thus causes the sleeve 44 to expand along the slit 58 to accommodate at least a portion of the cannula chamber (fig. 12). The distal end of the sleeve 44 extends sufficiently outwardly from the distal incision 82 so that the sleeve may be pulled thereover to withdraw the sleeve from tissue. After placement of the distal portion of graft 46 in sleeve 44, sleeve 44 is pulled and proximal end 54 of sleeve 44 is compressed by the incised tissue defining the tunnel, forcing the sleeve against cannula chamber 140. While pulling the arteriovenous graft 46 into the tissue 78, the sleeve 44 is pulled axially distally until the sleeve 44 is withdrawn from the tissue. The pulling force withdraws the sleeve 44 from the distal incision 82 and gradually moves the arteriovenous graft 46 distally through the first incision 80 into the tissue 78. Without tissue pressing the sleeve 44 against the cannula lumen, the proximal end 54 of the sleeve 44 expands and releases the arteriovenous graft 46 as the proximal end 54 of the sleeve exits the distal incision 82. The graft 46 is left in the tissue extending from the incision (fig. 14). The pulling force is depicted by the arrow. The proximal end 54 of the arteriovenous graft 46 is then pulled proximally to pull the cannula lumen 140 of the arteriovenous graft 46 back into the tissue 78.

In another embodiment of the method of delivering the arteriovenous graft 46, the cannula chamber 140 is held in a desired anatomical position through the skin 78 while the sleeve 44 can be pulled axially distally relative to the arteriovenous graft 46 and withdrawn from the subcutaneous tissue path. Specifically, when the arteriovenous graft 46 is positioned subcutaneously as desired, the surgeon holds the graft 46 in place by pushing the graft through the skin. Continued pulling draws sleeve 44 from the driven vein graft 46 by the provided pulling force. The graft 46 remains within the anatomic subcutaneous tunnel. The surgeon now forms an anastomosis at each of the catheter ends 134, 136 of the graft 10 by suturing the end of the graft to the vessel at the desired location.

In another embodiment, the proximal end 54 of the sleeve 44 may be mechanically secured to the distal end 53 of the tunneling instrument 42 adjacent the tip 52 by a mechanical or interference fit, mechanical structure, thermal bonding, or by a biocompatible adhesive or other securing means. An exemplary binder is a thermoplastic fluoropolymer such as Fluorinated Ethylene Propylene (FEP). Other simple mechanical devices are possible, including press fit loops, staples or sutures or other fastening techniques acceptable for implantation into body tissue.

In one embodiment shown in fig. 17A and 17B, the proximal end 54 of the sleeve 44 includes an end wall 57 having a reduced axial opening 62 having a diameter less than the widest diameter of the tip 52. Because the material of sleeve 44 is semi-elastic, tip 52 may be forced through opening 62, but tip 52 cannot be easily removed because tip 52 has a larger diameter than opening 62. The sleeve 44 is thus secured to the distal end of the tunneling instrument 42.

Referring now to fig. 18, in another embodiment, the distal end of tunneling instrument 42 may be mechanically secured to proximal end 54 of sleeve 44 using a fastening element for securing the sleeve. The fastening element is secured directly to the tunneling instrument 42 as shown and indicated generally at 70. The fastening element 70 includes a snap clamp that may be used to couple the sleeve 44 to the shaft 48 such that the sleeve 44 attaches to and encapsulates at least a portion of the distal end and tip 52 of the tunneling instrument 42. The fastening clip includes a C-shaped body 72 and a centrally located pin 74 that lies in the same plane as the body 72 and extends radially inwardly into an opening defined by the body 72. The clip 70 is configured to receive and enclose a portion of the proximal end 54 of the sleeve 44. The distal end of the shaft, spaced from the tip 52, defines a bore 76 configured to receive the pin 74. Proximal end 54 of sleeve 44 is enclosed by clip 70. Sleeve 44 may be coupled to tip 51 by passing sleeve 44 over tip 52 and mounting clip 70 on sleeve 44. This causes the arms of the body 72 to expand outwardly together until the arms exceed the maximum diameter of the sleeve 44, thereby guiding the pin 74 through the sleeve 44 into the bore 76 in the shaft until the pin sits in the bore. The arms of the clamp 70 may then spring inwardly. This secures the sleeve 44 and tunneling instrument 42 together with the clip 70. The user may now pull graft 46 into the subcutaneous tunnel previously formed by tunneling instrument 42. It should be appreciated that clamp 70 may be used by sliding only end portions 134, 136 of implant 46 over tip 52 of tunneling instrument 42 and securing the implant with clamp 70.

In use, after the distal end of the tunneling instrument 42 without the sleeve 44 emerges from the second distal incision 82, the proximal end of the sleeve 44 is secured to the tip 52. After the sleeve 44 is attached to the tunneling instrument 42, the sleeve 44 extends distally from the distal end of the tunneling instrument 42. Tunneling instrument 42 is withdrawn proximally while sleeve 44 is pulled through the previously incised tissue defining the anatomic tunnel. Once the sleeve 44 has been pulled to the location of the first incision 80, the proximal end of the sleeve 44 is disconnected from the distal end of the tunneling instrument 42. The sleeve 44 remains in the tissue, forming an internal passageway through the sleeve that is large enough to allow the graft 46 to be subsequently passed. As described above, the graft 46 is loaded proximally and the sleeve 44 is withdrawn distally, which simultaneously pulls the attached graft 46 into and through the tunnel with the sleeve 44 until the proximal end 54 of the graft 46 exits the second incision 82. The sleeve 44 allows the surgeon to easily pull the vascular graft 46 through the anatomic tunnel with the sleeve 44, the sleeve 44 being significantly oversized compared to the outer diameter of the vascular graft 46.

Fig. 19 shows an embodiment of an apparatus including a sleeve 44, the sleeve 44 including an enlarged bubble portion 110 spaced from the ends 54, 56 for receiving the cannula chamber 40 of the graft 46. The enlarged diameter of the bubble portion 110 of the sleeve 44 allows the sleeve 44 to receive the entire cannula chamber 140 of the graft 46. Some force may be required to install graft 46 into the interior cavity of sleeve 44.

Fig. 20 illustrates an embodiment in which a sleeve is generally indicated at 200. The sleeve 200 is braided and each wire 202 of the braid may move independently of the other. The sleeve functions similarly to the previous embodiments.

The apparatus and method for implanting an arteriovenous graft including a sleeve 44 enclosing a tunneling instrument 42 to deploy the graft 46 during implantation has a number of advantages, including atraumatic implantation of the arteriovenous graft 46 and subsequent withdrawal of the associated sleeve 44. Sleeve 44 is a simple addition to conventional tunneling instruments. The sleeve provides a flexible, compressible, but rigid outer surface for the shaft 48 of the tunneling instrument 42, which may allow tunneling to occur more easily with less friction and resistance and less associated tissue damage during passage of the tunneling device when forming an anatomical tunnel. The graft 46 is inserted into the tissue cavity with the sleeve 44 with less trauma, less friction and less resistance during placement. Thus, the systems and methods described herein may reduce the damaging forces to surrounding tissue associated with an implantation procedure and minimize trauma to the tissue and its healing response. Due to the smoothness and low profile of the sleeve 44, the tunneling procedure may be faster and easier to use. The delivery system would allow the surgeon to avoid the use of sutures to attach the graft to the tunneler. This facilitates immediate or early cannulation of a subsequently implanted vascular graft.

The embodiments of the tunneling device described herein are shown for surgical procedures performed with vascular grafts that are suitable for implantation into the body and for reestablishing or redirecting blood flow beyond the occluded area. Implantation is a necessary surgical step in peripheral vascular surgical procedures for all peripheral, vascular access and anatomic external graft locations. An arteriovenous graft is positioned in a tunnel within body tissue for securing the graft to an existing peripheral vessel to form a bypass around the vessel or a portion thereof, or connecting an artery and a vein to form an arteriovenous shunt. Vascular grafts may also connect arteries to arteries. Those of ordinary skill in the art will also recognize that the described embodiments of the tunneling device are not designed for a particular vascular graft, but are generally applicable to many different types of vascular grafts, which may be synthetic grafts or natural tissue grafts constructed of different materials. Thus, it should be understood that several tunneling devices described and illustrated herein may be used with more arteriovenous grafts than those illustrated in the figures, including grafts without a cannula chamber, biological grafts, and fistulae. In addition, the devices and methods may be used in other surgical implantation procedures where it is desired to place a medical device or other object within subcutaneous tissue.

Claims

1. A device for subcutaneous delivery of a vascular arteriovenous graft in patient tissue, the device comprising a cannula lumen and having a proximal end and a distal end and a length extending between the proximal end and the distal end along a longitudinal axis, the device using a rigid tunneling instrument comprising an elongated shaft having a handle at the proximal end of the shaft and a removable tip at the distal end of the shaft for creating a path in subcutaneous tissue, the subcutaneous delivery device comprising:

an elongate tubular sleeve having a length and defining an inner lumen, the sleeve being adapted to be slidably positioned over at least a portion of the shaft of the tunneling instrument between the handle and the tip such that once the tunneling instrument has been advanced to a desired subcutaneous anatomical location, the shaft is selectively removed from the sleeve while the sleeve remains positioned at the desired anatomical location, the sleeve having a slit extending along the length of the sleeve from the proximal end of the sleeve to a point intermediate the length of the sleeve,

wherein the lumen formed at the proximal end of the sleeve is adapted to receive the distal end of the graft and at least a portion of the cannula chamber such that the proximal portion of the sleeve gradually expands along the slit to provide an enlarged diameter for receiving the cannula chamber, and

wherein application of a longitudinal force from a distal end of the sleeve to the sleeve is effective to cause movement of the sleeve in a distal direction during removal of the sleeve from tissue such that the graft is secured in the sleeve by radial compression of the sleeve for pulling the graft and sleeve through the tunnel for deployment of the vascular graft.

2. The subcutaneous delivery device according to claim 1, wherein said sleeve is adapted to receive substantially the entire length of said shaft between said handle and said tip.

3. The subcutaneous delivery device according to claim 1, wherein the sleeve tapers uniformly from the proximal end to the distal end such that the distal end has a diameter that decreases from the proximal end.

4. The subcutaneous delivery device according to claim 1, wherein the slit is linear.

5. The subcutaneous delivery device according to claim 1, wherein said sleeve includes an enlarged diameter portion adjacent said proximal end, said enlarged diameter portion of said sleeve being adapted to receive said cannula chamber.

6. A device for subcutaneous delivery of a vascular arteriovenous graft in tissue of a patient, the device comprising a cannula chamber and having a proximal end and a distal end and a length extending between the proximal end and the distal end along a longitudinal axis, the subcutaneous implantation device comprising:

a rigid tunneling instrument for creating a path in subcutaneous tissue, the tunneling instrument comprising

An elongate shaft having a handle at a proximal end of the shaft, an

A removable tip at a distal end of the shaft; and

an elongate tubular sleeve having a length and defining an inner lumen, the sleeve having a slit extending along the length of the sleeve from the proximal end to a point intermediate the length of the sleeve, the sleeve configured to be slidably positioned over at least a portion of the shaft of the tunneling instrument between the handle and the distal end,

wherein once the tunneling instrument has been advanced to a desired subcutaneous anatomical location, the shaft is selectively removed from the sleeve while the sleeve remains positioned at the anatomical location,

wherein the lumen is adapted to receive a distal end of the graft and at least a portion of the cannula chamber via a proximal end of the sleeve such that the proximal portion of the sleeve gradually expands along the slit to provide an enlarged diameter for receiving the cannula chamber, and

wherein, for removing the sleeve from tissue, application of a longitudinal force to the sleeve from a distal end of the sleeve is effective to cause movement of the sleeve in a distal direction such that the arteriovenous graft is secured in the sleeve by radial compression of the tissue about the sleeve for pulling the arteriovenous graft and the sleeve through the tunnel such that the vascular graft is deployed.

7. The subcutaneous implant device of claim 6, wherein the sleeve is configured to receive substantially an entire length of the shaft between the handle and the tip.

8. The subcutaneous implant device of claim 6, wherein the sleeve tapers uniformly from a proximal end to a distal end such that the distal end has a diameter that decreases from the proximal end.

9. The subcutaneous implant device according to claim 6, wherein said slit is linear.

10. The subcutaneous implant device of claim 6, wherein the sleeve includes an enlarged diameter portion adjacent the proximal end, the enlarged diameter portion adapted to receive the cannula chamber.

11. The subcutaneous implant device of claim 6, wherein the sleeve includes a terminal wall at the proximal end, the wall having an axial opening for receiving the tip of the tunneling instrument for connection of the sleeve to the tunneling instrument.

12. The subcutaneous delivery device of claim 6, further comprising a clip comprising a pin, wherein the shaft has a hole adjacent the tip, the hole defining an axial channel for receiving the pin and capturing the sleeve between the clip and the shaft.

13. A system for delivering a medical device under the endothelium of a patient, the subcutaneous delivery device comprising:

An elongate shaft having a handle at a proximal end of the shaft, and

a removable tip at a distal end of the shaft;

an arteriovenous graft comprising a cannula chamber and having proximal and distal ends and a length extending along a longitudinal axis between the proximal and distal ends; and

an elongate tubular sleeve having a length and defining an inner lumen, the sleeve having a slit extending along the length of the sleeve from the proximal end to a point intermediate the length of the sleeve, the sleeve configured for slidable positioning over at least a portion of the shaft of the tunneling instrument between the handle and the distal end,

wherein the lumen is configured to receive the distal end of the graft and at least a portion of the cannula chamber via the proximal end of the sleeve such that the proximal end portion of the sleeve gradually expands along the slit to provide an enlarged diameter for receiving the cannula chamber, and

wherein upon removal of the sleeve from the tissue, application of a longitudinal force to the sleeve from the distal end of the sleeve is effective to cause movement of the sleeve in a distal direction such that the arteriovenous graft is secured in the sleeve by radial compression of the tissue about the sleeve for pulling the arteriovenous graft and sleeve through the tunnel, deploying the vascular graft.

14. The subcutaneous delivery system according to claim 13, wherein said sleeve is configured to receive substantially the entire length of said shaft between said handle and said tip.

15. The subcutaneous delivery system according to claim 13, wherein the sleeve tapers uniformly from the proximal end to the distal end such that the distal end has a diameter that decreases from the proximal end.

16. The subcutaneous delivery system according to claim 13, wherein the slit is linear.

17. The subcutaneous delivery system according to claim 13, wherein the sleeve includes an enlarged diameter portion adjacent the proximal end, the enlarged diameter portion configured to receive the cannula chamber.

18. The subcutaneous delivery system according to claim 13, wherein said sleeve includes a wall at said proximal end, said wall having an axial opening for receiving said tip of said tunneling instrument for connection of said sleeve to said tunneling instrument.

19. The subcutaneous delivery system according to claim 13, further comprising a clip comprising a pin, wherein said shaft has a hole adjacent said tip, said hole defining an axial channel for receiving said pin to connect said shaft to said sleeve for applying a pulling force in a proximal direction.

20. A method for subcutaneously implanting an arteriovenous graft into tissue of a subject, the arteriovenous graft comprising a cannula chamber and having a proximal end and a distal end and a length extending along a longitudinal axis between the proximal end and the distal end, the implantation method comprising the steps of:

cutting tissue of the subject in a first proximal position and a second distal position spaced apart from the first proximal position;

providing a rigid tunneling instrument comprising an elongate shaft having a handle at a proximal end of the shaft and a removable tip at a distal end of the shaft;

removing the tip and disposing a tubular sleeve over at least a portion of the shaft between the tip and the handle, the sleeve having a slit extending along a length of the sleeve from the proximal end to a point intermediate the length of the sleeve;

securing the tip to the distal end of the shaft and inserting the tip into a first incision and advancing the instrument and the sleeve subcutaneously through tissue along a path until the tip exits a second incision such that the distal end of the sleeve extends from the second incision and the proximal end of the sleeve extends from the first incision;

removing the tip prior to pulling the tunneling instrument proximally through the handle to remove the shaft from the sleeve in tissue;

inserting the distal end of the graft into the proximal end of the sleeve until the cannula chamber at least partially enters the sleeve, causing the sleeve to expand along the slit to accommodate at least a portion of the chamber; and

pulling the sleeve distally to withdraw the sleeve from the tissue while the proximal end of the sleeve is compressed by the severed tissue defining the tunnel, forcing the sleeve against the chamber to pull the graft through the tissue with the sleeve.

21. The method of claim 20, further comprising pulling the proximal end of the arteriovenous graft proximally to pull the cannula lumen of the arteriovenous graft back into the tissue.