Apparatus and method for implanting an arteriovenous graft - Patent application

Abstract

The apparatus for delivering a vascular arteriovenous graft includes a tubular sleeve (44) defining a lumen adapted to be slidably disposed over a tunneling instrument (42). Once the tunneling instrument is advanced to a desired subcutaneous anatomical location, the shaft is removed leaving the sleeve in place within the tissue. The sleeve has a linear slit (58) extending from a proximal end to a midpoint of the length of the sleeve. The lumen receives the distal end of the graft and at least a portion of the cannulation chamber, and the end of the sleeve gradually expands along the slit to provide an enlarged diameter to accommodate the cannulation chamber. A longitudinal force on the sleeve upon removal of the sleeve from the tissue secures the graft within the sleeve by radial compression of the sleeve and pulls the graft and sleeve through the tunnel to deploy the vascular graft.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 166,794 and U.S. Provisional Application No. 63 / 166,790, both filed on March 26, 2021, the contents of both of which are incorporated herein in their entireties.

[0002] background Apparatus and methods for implanting an arteriovenous graft, and more particularly, for using a tunneling instrument in forming a subcutaneous anatomical tunnel for implanting an arteriovenous graft, including the use of a removable sleeve surrounding the tunneling instrument for delivery of the arteriovenous graft, are described. [Background technology]

[0003] A vascular arteriovenous graft is a tubular device suitable for implantation in the body to redirect blood flow between blood vessels. Surgical implantation of an arteriovenous graft requires placement of the graft in subcutaneous tissue. The first step in the implantation procedure is to create a subcutaneous anatomical pathway or "tunnel" for passing the arteriovenous graft between the anastomosis sites, commonly referred to as the graft tunnel. This is a necessary surgical step in peripheral vascular procedures for all peripheral vascular access and additional anatomical graft locations. The arteriovenous graft is placed in the tunnel in the body tissue to either fix the graft to an existing peripheral vessel to create a bypass around the vessel or a portion thereof, or to create an arterial and venous connection to create an arteriovenous shunt. Vascular grafts can also connect arteries to arteries.

[0004] A conventional tunneling device includes a long, rigid rod with a handle at the proximal end and a bullet-shaped tip at the distal end. The rod can vary in size and shape and can have a straight, curved or semicircular shaft, allowing for a variety of graft placement locations and locations. In the tunneling procedure, a first proximal incision and a second distal incision are made at the selected anastomosis area. The tip of the distal end of the tunneling device is then inserted into the proximal incision. The tip of the tunneling device is then forced through the subcutaneous tissue and a pathway is created between the incisions by blunt dissection 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 end of the tunneling device with a sterile suture. The tunneling instrument and attached arteriovenous graft are then pulled proximally along a pathway through the previously incised graft tunnel until the proximal end of the arteriovenous graft extends from the proximal incision. Once the arteriovenous graft is properly positioned, the graft is detached from the distal end of the tunneling instrument, a portion of the graft is removed, anastomoses are formed between the ends of the graft and the surrounding vessels in the area of ​​vasculature being bypassed, and the incisions are closed.

[0005] The process of pulling the tunneling instrument and attached arteriovenous graft through the graft tunnel can require significant force. The force required depends on several factors, including the relative sizes 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 with a retaining sleeve that reduces friction when passing through the subcutaneous tissue. After the implant procedure, the sleeve is removed by pulling or unwinding on the device to retract the sleeve. Rotating the sleeve during retraction reduces the pulling force required compared to sliding the sleeve over the device and pulling the sleeve off, but significant force may still be required to retract the sleeve after the arteriovenous graft implant procedure.

[0006] For the reasons stated above, there is a need for an apparatus and method for implanting arteriovenous grafts that minimizes the force required to deliver the graft. The new apparatus in the form of a sleeve should help define and support the length of the anatomical tunnel created by the tunneling device. The sleeve should be capable of being reliably withdrawn with low pulling forces to minimize problems associated with excessive axial forces on the sleeve during retraction. The new apparatus and method should also be capable of implanting any type of vascular graft, including but not limited to ePTFE and native tissue grafts. Summary of the Invention

[0007] Abstract An apparatus is provided for subcutaneously delivering a vascular arteriovenous graft into tissue of a patient, the graft including a cannulated chamber and having proximal and distal ends and a length extending along a longitudinal axis between the proximal and distal ends. The apparatus uses a rigid tunneling instrument including an elongated shaft having a handle at a proximal end of the shaft and a removable tip at a distal end of the shaft to form a passageway in the subcutaneous tissue. The subcutaneous delivery apparatus includes an elongated tubular sleeve having a length and defining a lumen, the sleeve adapted to be slidably disposed over at least a portion of the shaft of the tunneling instrument between the handle and the tip. Once the tunneling instrument is advanced to a desired subcutaneous anatomical location, the shaft is selectively removed from the sleeve while the sleeve remains disposed in the desired anatomical location. The sleeve has a linear slit extending along the length of the sleeve from the proximal end to a midpoint of the length of the sleeve. A lumen defined at the proximal end of the sleeve is adapted to receive the distal end of the graft and at least a portion of the cannulation chamber, such that the proximal end portion of the sleeve gradually expands along the slit to provide an enlarged diameter to accommodate the cannulation chamber. Application of a longitudinal force to the sleeve from the distal end of the sleeve is effective to move the sleeve distally upon removal of the sleeve from the tissue, thereby pulling the graft and sleeve through the tunnel and causing radial compression of the sleeve to secure the graft within the sleeve for deployment of the vascular graft.

[0008] In one embodiment, the sleeve is adapted to receive substantially the entire length of the shaft between the handle and the tip, hi another embodiment, the sleeve is uniformly tapered from the proximal end to the distal end such that the distal end has a reduced diameter from the proximal end.

[0009] In one embodiment, the sleeve includes an enlarged diameter portion adjacent the proximal end adapted to receive the cannulation chamber.

[0010] Also provided is an apparatus for subcutaneously implanting a vascular arteriovenous graft into tissue of a patient, the graft including a cannulated chamber and having proximal and distal ends and a length extending along a longitudinal axis between the proximal and distal ends. The subcutaneous implantation apparatus includes a rigid tunneling instrument for forming a passageway in subcutaneous tissue. The tunneling instrument includes an elongated shaft having a handle at a proximal end of the shaft and a removable tip at a distal end of the shaft. The elongated tubular sleeve has a length and defines a lumen. A linear slit extends along the length of the sleeve from the proximal end to a midpoint of the length of the sleeve. The sleeve is configured to be slidably disposed over at least a portion of the shaft of the tunneling instrument between the handle and the tip. Once the tunneling instrument is advanced to a desired subcutaneous anatomical location, the shaft is selectively removed from the sleeve while the sleeve is disposed at the anatomical location. The lumen is adapted to receive the distal end of the graft and at least a portion of the cannulation chamber through the proximal end of the sleeve, whereby the proximal end portion of the sleeve gradually expands along the slit to provide an enlarged diameter to accommodate the cannulation chamber. Application of a longitudinal force to the sleeve from the distal end of the sleeve is effective to move the sleeve distally to remove the sleeve from the tissue, whereby the arteriovenous graft is secured within the sleeve by radial compression of the tissue around the sleeve. The arteriovenous graft and sleeve are pulled through the tunnel to deploy the vascular graft.

[0011] In one embodiment, the sleeve is adapted to receive substantially the entire length of the shaft between the handle and the tip, hi another embodiment, the sleeve is uniformly tapered from the proximal end to the distal end such that the distal end has a reduced diameter from the proximal end.

[0012] In one embodiment, the sleeve includes an enlarged diameter portion adjacent the proximal end that is adapted to receive the cannulation chamber.

[0013] The sleeve features a wall at a proximal end having an axial opening for receiving the tip of a tunneling instrument to connect the sleeve to the tunneling instrument, and a clip including a pin, the shaft having a hole adjacent the tip that defines an axial passage for receiving the pin.

[0014] A system for subcutaneously delivering a medical device into a patient is provided, the subcutaneous delivery system including a tunneling instrument having a shaft with 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 disposed over a substantial portion of the outer surface of the shaft. The sleeve is configured to apply radial pressure to a cannulation chamber upon application of a distal longitudinal force to the sleeve to implant the vascular graft and to move the sleeve distally during removal of the sleeve.

[0015] In one embodiment, the sleeve is adapted to receive substantially the entire length of the shaft between the handle and the tip, hi another embodiment, the sleeve is uniformly tapered from the proximal end to the distal end such that the distal end has a reduced diameter from the proximal end.

[0016] In one embodiment, the sleeve includes an enlarged diameter portion adjacent the proximal end that is adapted to receive the cannulation chamber.

[0017] The sleeve features a wall at a proximal end having an axial opening for receiving the tip of a tunneling instrument to connect the sleeve to the tunneling instrument.

[0018] In another embodiment, the subcutaneous delivery system can further include a clip including a pin, and the shaft has a hole adjacent the tip defining an axial passage for receiving the pin for connecting the shaft to the sleeve for applying a pulling force in the proximal direction.

[0019] A method of subcutaneously implanting an arteriovenous graft into tissue of a subject is also provided. The arteriovenous graft includes a cannulated chamber, a proximal end, and a distal end, and a length extending along a longitudinal axis between the proximal end and the distal end. The method of implantation includes incising tissue of a subject at a first proximal location and a second distal location spaced from the first proximal location. A rigid tunneling instrument is provided including 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 placed over at least a portion of the shaft between the tip and the handle, the sleeve having a slit extending along the length of the sleeve from the proximal end to a midpoint of the length of the sleeve. The tip is secured to the distal end of the shaft and inserted into the first incision, and the user advances the instrument and sleeve subcutaneously through the tissue along the passage until the tip 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, followed by pulling the tunneling instrument proximally by the handle to remove the shaft from the sleeve within the tissue. The distal end of the graft is inserted into the proximal end of the sleeve until the cannulated chamber at least partially enters the sleeve and the sleeve expands along the slit to accommodate at least a portion of the chamber. The method includes pulling the sleeve distally to withdraw it from the tissue, while the proximal end of the sleeve is compressed by the resected tissue defining the tunnel, forcing the sleeve against the chamber to pull the graft through the tissue with the sleeve.

[0020] In one embodiment, the method may further comprise the step of pulling the proximal end of the arteriovenous graft proximally to pull the cannulation chamber of the arteriovenous graft back into the tissue. [Brief description of the drawings]

[0021] BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the apparatus and methods used to form a subcutaneous anatomical tunnel, reference should be made to the embodiments illustrated in the accompanying drawings and described below. In the drawings:

[0022] [Figure 1] FIG. 1 is a perspective view from the distal end of a tapered sleeve for use with a tunneling device for subcutaneous deployment of an arteriovenous graft.

[0023] [Diagram 2] FIG. 2 is a perspective view from the proximal end of the sleeve as shown in FIG.

[0024] [Diagram 3] FIG. 3 is a proximal end view of the sleeve as shown in FIG.

[0025] [Figure 4] FIG. 4 is a distal end view of the sleeve as shown in FIG.

[0026] [Diagram 5] FIG. 5 is a plan view of the sleeve as shown in FIG.

[0027] [Figure 6] FIG. 6 is a bottom view of the sleeve as shown in FIG.

[0028] [Figure 7] FIG. 7 is an exploded perspective view of a device for use in forming a subcutaneous anatomical tunnel and delivering an arteriovenous graft.

[0029] [Figure 8] FIG. 8 is a perspective view of the tunneling and delivery device as shown in FIG. 7 in a tunneling state with a sleeve on the tunneling instrument.

[0030] [Figure 9]9 is an enlarged perspective view of the shaft of the tunneling instrument as shown in FIG. 7 inserted within the sleeve as shown in FIG.

[0031] [Figure 10] FIG. 10 is a perspective view showing a tunneling instrument covered by a sleeve as shown in FIG. 8, deployed in a portion of tissue and with its ends extending from spaced incisions.

[0032] [Figure 11] FIG. 11 is a perspective view as shown in FIG. 10 with the tunneling instrument removed and showing the sleeve within the tissue.

[0033] [Figure 12] FIG. 12 is a perspective view as shown in FIG. 11 showing an arteriovenous graft including a cannulated chamber mounted on the proximal end of the sleeve.

[0034] [Figure 13] FIG. 13 is a perspective view as shown in FIG. 12 showing the proximal end of the sleeve exiting the tissue and the cannulation chamber of the arteriovenous graft partially extending from the tissue.

[0035] [Figure 14] FIG. 14 is a perspective view as shown in FIG. 13 with only the arteriovenous graft remaining in the tissue with both ends extending out of the tissue at each incision.

[0036] [Figure 15] FIG. 15 is a cross-sectional perspective view of the proximal end of another embodiment of a sleeve for use with a tunneling instrument.

[0037] [Figure 16] FIG. 16 is a cross-sectional perspective view of the proximal end of a third embodiment of a sleeve for use with a tunneling instrument.

[0038] [Figure 17]17A and 17B are perspective views of a fourth embodiment of a sleeve for use with a tunneling instrument.

[0039] [Figure 18] FIG. 18 is a perspective view of a mechanical fastening element for connecting a sleeve to a tunneling instrument as shown in FIG.

[0040] [Figure 19] 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 cannulated chamber.

[0041] [Figure 20] 20A and 20B are perspective views of a sixth embodiment of a sleeve and tunneling device for delivering an arteriovenous graft. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] explanation Certain terminology is used herein for convenience only and should not be construed as limiting. For example, words such as "upper", "lower", "left", "right", "horizontal", "vertical", "upward", "downward", "top", "bottom", etc. are merely descriptive of the configurations shown in the figures. In fact, components may be oriented in any direction, and thus, unless otherwise specified, the terms should be understood to encompass such variations. The words "interior" and "exterior" refer to directions toward and away from the geometric center of the core and designated portions thereof, respectively. This term includes the words specifically mentioned above, derivatives thereof, and words of similar meaning.

[0043] Referring now to the drawings, where like reference numerals indicate corresponding or similar elements throughout the several views, an embodiment of an apparatus for use in forming a subcutaneous anatomical tunnel for implanting a vascular arteriovenous graft in a patient is shown in FIG. 1 and generally designated 40. The tunneling and implantation 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. The 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 that increases in diameter from the pointed distal end. During the tunneling procedure, the shaft 48 and tip 52 are advanced through the subcutaneous tissue by application of an axial force in a distal direction on the handle 50, with the tip facilitating the blunt dissection of tissue inherent to the tunneling procedure. The shaft 50 and tip 52 may be made from stainless steel, although one skilled in the art would 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 Tunneler, available from CRBard, Inc., Moncks Corner, South Carolina.

[0044] An arteriovenous graft 46 suitable for use in the device and method is described in U.S. Patent No. 9,585,998, the entire contents of which are incorporated herein by reference. The arteriovenous graft 46 includes a conduit 132 having a first end 134 and a second end 136. The first end 134 is configured to connect at its end to a first blood vessel of the subject, such as an artery. The second end 136 is configured to connect 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 134 to the second end 136. At least one cannulation chamber 140 is disposed between the first end 134 and the second end 136 of the conduit 132. The conduit 132 extends through the chamber 140. The cannulation chamber 140 has an open forward portion defining a cannulation port configured to receive a dialysis needle. It will be appreciated that the tunneling device may be used with any vascular graft, not just native tissue grafts or fistulas.

[0045] 2-7, the tubular sleeve 44 comprises a hollow tube that is open at both the proximal end 54 and the 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 the sleeve 44 at the distal end 56 is less than the maximum dimension of the tip 52. As shown in FIG. 8, the sleeve 44 proximally engages the tip 52 of the tunneling instrument 42 and extends to the handle 50 of the tunneling instrument 42. The sleeve 44 is dimensioned in diameter and length to be slidably disposed over and surround at least a portion of the shaft 48 of the tunneling instrument 42 during the tunneling procedure. Following tissue tunnel formation, a pulling force is applied to the handle 50 in a proximal direction along the longitudinal axis of the shaft 48, removing the tip 52 and withdrawing the shaft 48 from the sleeve 44. The sleeve 44 remains within the tissue and provides for insertion of the graft 46 through the tunneled tissue passage due to the unrestricted flexible nature of the surface of the sleeve 44 .

[0046] As best seen in FIGS. 6 and 7, the sleeve 44 has a linear slit 58 oriented along the longitudinal axis of the sleeve that extends from the open proximal end 54 to a location along the length of the sleeve 44. The slit 58 may generally be oriented 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 the arteriovenous graft is inserted into the proximal end 54 of the sleeve. In the illustrated embodiment, the sleeve 44 has holes 60 at the ends of the slit 58 to prevent the sleeve from tearing from the slit 58 when the sleeve is expanded. The slit 58 can vary in length and shape. A shorter slit can accommodate only a smaller area of ​​the cannulation chamber 140, reducing surface damage. A longer slit 58 allows the sleeve to accommodate more of the cannulation chamber 140 for better clamping the cannulation chamber 140 during delivery to reduce the risk of the sleeve releasing before the graft 46 is fully within the anatomical tunnel. The opening of the slit 58 can also have different shapes. FIG. 15 shows material removal from the proximal end 54 of the sleeve 44 to form a triangular opening. Similarly, FIG. 16 shows the slit 58 forming a straight opening for receiving the cannulated chamber 140. Multiple slits (not shown) can also be used. Multiple slits allow a larger cannulated chamber 140 to be inserted into and clamped by the sleeve 44. It is understood that the slits 58 at the ends of the sleeve 44 are not necessary when the sleeve is used to deploy a conventional biograft. In this application, no slits are necessary since the lumen is larger than the diameter of the graft. The graft can simply be slidable into the sleeve 44 within the tissue, and the sleeve 44 is withdrawn from the tissue leaving the graft behind.

[0047] The sleeve 44 can be made of any biocompatible material that is smooth, flexible, and compressible. Suitable materials can be porous, non-porous, permeable, or impermeable. Because the sleeve material does not flex excessively, the sleeve 44 can absorb the tensile forces 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 polyesters and polyimides. Suitable materials are available from Colorite, Ridgefield, NJ. By varying the material and properties of the sleeve, such as thickness and width, various desired configurations can be achieved. The sleeve 44 may be extruded. It is understood that the sleeve 44 can have a coefficient of friction that is low enough to allow removal of the sleeve from the anatomical tunnel by an axial pulling force on the sleeve.

[0048] In another embodiment, the sleeve 44 has a "dual wall" construction. A double wall sleeve is formed from two layers of thin, flexible, compressible material closed at both ends. An inner portion or first wall of the sleeve 44 has a predetermined durometer and extends radially and axially over the sleeve from a location at the proximal end 54 of the sleeve 44 to a distal end 56 of the sleeve. An outer portion or second wall of the sleeve extends radially and axially over the inner portion from the proximal end 54 to the distal end 56 of the sleeve 44. The durometer of the inner portion of the double wall sleeve 44 is less than the durometer of the outer portion, providing a harder outer shell for the sleeve and a more flexible inner portion surrounding the graft 46 to prevent damage during deployment.

[0049] The smooth outer surface of the sleeve material allows for a low coefficient of friction for the sleeve 44. This results in easier insertion of the tunneling instrument 42 and sleeve 44 through tissue with less trauma, less friction, less blunt dissection, and less drag during placement. Due to the smoothness and low profile of the sleeve 44 relative to the shaft 48, the sleeve does not substantially increase the outer diameter of the tunneling instrument 42.

[0050] The sleeve 44 may optionally be coated on its outer surface with a lubricating material to provide a low coefficient of friction to aid in the insertion and movement of the sleeve 44 and associated tunneling instrument 42 through tissue while minimizing tissue drag and trauma during insertion or removal of the sleeve after the implantation procedure. This minimizes tissue drag and trauma during insertion of the tunneling instrument 42 and sleeve 44 or removal of the sleeve 44 during the implantation procedure of the graft 46. It is understood that a variety of coatings, including therapeutic agents, for delivery of therapeutic materials are available. 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 immediately prior to use. In another embodiment, the applicant contemplates a kit including the 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.

[0051] In use, a first proximal incision 80 and a second distal incision 82 spaced from the first incision are first made through the patient's skin 78 into the underlying subcutaneous tissue. The tip 52 at the distal end 53 of the tunneling instrument 42 is inserted into the first incision 80 with the sleeve 44 on the shaft 48 and then pushed horizontally through the subcutaneous tissue along the path until the tip exits the second incision 82 (FIG. 10). The tip 52 is then removed by the surgeon, and the tunneling instrument 42 is pulled proximally from the first incision 80 by the handle 50 to remove the shaft 48 from the tissue. The sleeve 44 is left behind in the body tissue. As shown in FIG. 11, the ends 54, 56 of the sleeve 44 extend proximally and distally from the first and second incisions 80, 82 outside the skin 78.

[0052] The distal end portion 136 of the graft 46 is inserted into the proximal end 54 of the sleeve 44 until the cannulated chamber 140 is at least partially inside the sleeve 44 (FIG. 12). The sleeve 44 allows the surgeon to easily push the vascular graft 46 into the lumen defined by the sleeve, which is oversized relative to the outer diameter of the conduit 132 of the vascular graft 46. However, the sleeve 44 is configured such that the outer diameter of the cannulated chamber 140 is larger than the inner diameter of the sleeve. Thus, the cannulated chamber 140 causes the sleeve 44 to expand along the slit 58 to accommodate at least a portion of the chamber (FIG. 12). The distal end of the sleeve 44 extends sufficiently out from the distal incision 82 so that it can be pulled to withdraw the sleeve from the tissue. After the distal portion of the graft 46 is positioned within the sleeve 44, the sleeve 44 is pulled such that the proximal end 54 of the sleeve 44 is compressed by the excised tissue defining the tunnel, thereby forcing the sleeve against the cannulation chamber 140. The sleeve 44 is pulled axially in a distal direction, drawing the arteriovenous graft 46 into the tissue 78, 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 and into the tissue 78. Without the tissue compressing the sleeve 44 against the cannulation chamber, the proximal end 54 of the sleeve 44 expands, releasing the arteriovenous graft 46 as the proximal end 54 of the sleeve passes through the distal incision 82. The arteriovenous graft 46 remains within the tissue extending from the incision (FIG. 14). The pulling force is indicated by the arrows. The proximal end 54 of the arteriovenous graft 46 is then pulled proximally to pull the cannulation chamber 140 of the arteriovenous graft 46 back into the tissue 78 .

[0053] In another embodiment of the method of delivering the arteriovenous graft 46, the cannulated chamber 140 is held in the desired anatomical location through the skin 78 while the sleeve 44 is pulled axially distally relative to the arteriovenous graft 46 and can be withdrawn from the subcutaneous tissue pathway through the second incision 82. Specifically, once the arteriovenous graft 46 is subcutaneously positioned as desired, the surgeon holds the graft 46 in place by pushing the graft across the skin. As tension continues, the applied tensile force withdraws the sleeve 44 from over the arteriovenous graft 46. The graft 46 remains in the anatomical subcutaneous tunnel. The surgeon then forms an anastomosis to each conduit end 134, 136 of the graft 10 by suturing the ends of the graft to the blood vessels in the desired locations.

[0054] 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 fastening means. An example of an adhesive is a thermoplastic fluoropolymer such as fluorinated ethylene propylene (FEP). Other simple mechanical means are also possible, including a compression fit collar, staples or sutures, or other fastening techniques acceptable for implantation into bodily tissue.

[0055] 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 maximum diameter of the tip 52. Because the material of the sleeve 44 is semi-elastic, the tip 52 can be forced through the opening 62, but because the diameter of the tip 52 is greater than the opening 62, it cannot be easily removed. Thus, the sleeve 44 is secured to the distal end of the tunneling instrument 42.

[0056] 18, in another embodiment, the distal end of the tunneling instrument 42 may be mechanically secured to the proximal end 54 of the sleeve 44 using a fastening element to secure the sleeve. The fastening element is secured directly to the tunneling instrument 42 and is generally indicated at 70. The fastening element 70 comprises a snap-on clip that can be used to connect the sleeve 44 to the shaft 48 such that the sleeve 44 is connected to and surrounds at least a portion of the distal end and tip 52 of the tunneling instrument 42. The fastening clip comprises a C-shaped body 72 and a pin 74 centrally located in the same plane as the body 72 and extending radially inward toward an opening defined by the body 72. The clip 70 is configured to receive and surround a portion of the proximal end 54 of the sleeve 44. The distal end of the shaft spaced from the tip 52 defines a hole 76 configured to receive the pin 74. The proximal end 54 of the sleeve 44 is surrounded by the clip 70. The sleeve 44 can be coupled to the tip 51 by passing the sleeve 44 over the tip 52 and attaching the clip 70 over the sleeve 44. This causes the arms of the body 72 to expand outward together until they exceed the maximum diameter of the sleeve 44, leading the pin 74 through the sleeve 44 and into the shaft hole 76 until the pin seats in the hole. The arms of the clip 70 can then spring inward. This secures the sleeve 44 and the tunneling instrument 42 together with the clip 70. The user can then pull the graft 46 into the subcutaneous tunnel previously formed by the tunneling instrument 42. It will be appreciated that the clip 70 is secured by sliding only the ends 134, 136 of the graft 46 over the tip 52 of the tunneling instrument 42 and securing the graft with the clip 70.

[0057] In use, after the distal end of the tunneling instrument 42, without the sleeve 44, exits 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. The tunneling instrument 42 is withdrawn proximally while simultaneously pulling the sleeve 44 through the pre-incised tissue defining the anatomical tunnel. Once the sleeve 44 is withdrawn to the site of the first incision 80, the proximal end of the sleeve 44 is detached from the distal end of the tunneling instrument 42. The sleeve 44 remains within the tissue, forming an internal passage therethrough that is large enough to allow subsequent passage of the graft 46. The graft 46 is loaded proximally as described above and the sleeve 44 is withdrawn distally, which simultaneously draws the attached graft 46 along with the sleeve 44 into and through the tunnel 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 anatomical tunnel with the sleeve 44 being substantially oversized compared to the outer diameter of the vascular graft 46.

[0058] 19 illustrates an embodiment of the device that includes a sleeve 44 that includes an enlarged bulbous portion 110 spaced from ends 54, 56 for receiving the cannulated chamber 40 of the graft 46. The enlarged diameter of the bulbous portion 110 of the sleeve 44 allows the sleeve 44 to receive the entire cannulated chamber 140 of the graft 46. Some force may be required to seat the graft 46 within the lumen of the sleeve 44.

[0059] 20 shows an embodiment in which the sleeve is generally designated 200. The sleeve 200 is a woven fabric, and each of the threads 202 of the fabric can move independently of each other. The sleeve functions similarly to the previous embodiment.

[0060] The apparatus and method for implanting an arteriovenous graft, including a sleeve 44 surrounding a tunneling instrument 42 for deploying the graft 46 during the implantation procedure, has many advantages, including atraumatic implantation of the arteriovenous graft 46 and subsequent withdrawal of the associated sleeve 44. The sleeve 44 is a simple addition to a conventional tunneling instrument. The sleeve provides a flexible, compressible, yet rigid outer surface to the shaft 48 of the tunneling instrument 42, allowing for easier tunneling with less friction and resistance and associated tissue damage during passage of the tunneling device in forming the anatomical tunnel. Inserting the graft 46 with the sleeve 44 into the tissue cavity results in less trauma, friction and drag during placement. Thus, the systems and methods described herein can reduce the traumatic forces to the surrounding tissue associated with the implantation procedure, minimizing the resulting trauma to this tissue and its healing response. Due to the smoothness and collapsible low profile of the sleeve 44, the tunneling procedure can be faster and easier to use. This delivery system allows the surgeon to avoid the use of sutures to attach the graft to the tunneler, facilitating immediate or early cannulation of the vascular graft for subsequent implantation.

[0061] The embodiments of the tunneling device as described herein are shown to be used in procedures with vascular grafts suitable for implantation into the body and are used to re-establish or redirect blood flow past the occluded area. The implantation procedure is a necessary surgical step in peripheral vascular procedures for all peripheral vascular access and additional anatomical graft locations. The arteriovenous grafts are placed in tunnels in body tissue to secure the graft to an existing peripheral vessel to create a bypass around the vessel or a portion thereof or to create an arteriovenous shunt. The vascular grafts can also connect arteries to arteries. Additionally, one skilled in the art will recognize that the embodiments of the tunneling device as described are not directed to a specific vascular graft design, but are generally applicable to many different types of vascular grafts, which can be synthetic grafts or natural tissue grafts made from different materials. Thus, it is understood that some of the tunneling devices described and illustrated herein can be used with more arteriovenous grafts than those illustrated in the drawings, including grafts without cannulation chambers, biological grafts, and fistulas. Additionally, the apparatus and methods may be used in other surgical implant procedures that require placement of medical devices or other objects within subcutaneous tissue.

Claims

1. 1. An apparatus for subcutaneously delivering a vascular arteriovenous graft into tissue of a patient, the graft including a cannulation chamber and having proximal and distal ends and a length extending along a longitudinal axis between said proximal and distal ends, the subcutaneous delivery apparatus using a rigid tunneling instrument including an elongated shaft having a handle at a proximal end of the shaft and having a removable tip at a distal end of the shaft to form a passageway in the subcutaneous tissue, the subcutaneous delivery apparatus comprising: an elongate tubular sleeve having a length and defining an internal lumen, said sleeve adapted to be slidably disposed over at least a portion of said tunneling instrument shaft between said handle and said tip, whereby upon advancement of said tunneling instrument to a desired subcutaneous anatomical location, said shaft is selectively removed from said sleeve while said sleeve remains disposed at the desired anatomical location, said sleeve having a slit extending along a length of said sleeve from a proximal end to a midpoint of the length of the sleeve; a lumen defined at the proximal end of the sleeve adapted to receive the distal end of the graft and at least a portion of the cannulation chamber, whereby the proximal end portion of the sleeve gradually expands along the slit to provide an enlarged diameter to accommodate the cannulation chamber; and A subcutaneous delivery device, wherein application of a longitudinal force to the sleeve from a distal end of the sleeve is effective to move the sleeve distally when removing the sleeve from tissue, thereby pulling the graft and the sleeve through a tunnel and causing radial compression of the sleeve to secure the graft within the sleeve for deploying a vascular graft.

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

3. The subcutaneous delivery device of claim 1 , wherein the sleeve is uniformly tapered from the proximal end to the distal end such that the distal end has a reduced diameter from the proximal end.

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

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

6. 1. An apparatus for subcutaneously implanting a vascular arteriovenous graft into tissue of a patient, the graft including a cannulated chamber, the graft having proximal and distal ends and a length extending along a longitudinal axis between the proximal and distal ends, the subcutaneous implantation apparatus comprising: a rigid tunneling instrument for forming a passageway within the subcutaneous tissue; wherein the tunneling tool comprises: an elongate shaft having a handle at a proximal end of the shaft; and a removable tip at a distal end of the shaft. It has an elongate tubular sleeve having a length and defining an internal lumen, said sleeve having a slit extending along a length of the sleeve from a proximal end to a midpoint of the length of the sleeve, said sleeve configured to be slidably disposed over at least a portion of the shaft of the tunneling instrument between the handle and the tip; Contains 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 in place at the anatomical location; the lumen is adapted to receive the distal end of the graft and at least a portion of the cannulation chamber through the proximal end of the sleeve, whereby the proximal end portion of the sleeve gradually expands along the slit to provide an enlarged diameter to accommodate the cannulation chamber; and A subcutaneous implant treatment device, wherein application of a longitudinal force to the sleeve from a distal end of the sleeve is effective to move the sleeve distally to remove the sleeve from tissue, thereby pulling the arteriovenous graft and the sleeve through a tunnel and causing the arteriovenous graft to be secured within the sleeve by radial compression of tissue around the sleeve to deploy a vascular graft.

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

8. 7. The subcutaneous implant treatment device of claim 6, wherein the sleeve is uniformly tapered from the proximal end to the distal end such that the distal end has a reduced diameter from the proximal end.

9. The subcutaneous implant treatment device of claim 6 , wherein the slit is linear.

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

11. The implant treatment apparatus of claim 6 , wherein the sleeve includes an end wall at the proximal end, the wall having an axial opening for receiving a tip of the tunneling instrument to connect the sleeve to the tunneling instrument.

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

13. 1. A system for subcutaneous delivery of a medical device into a patient, the subcutaneous delivery device comprising:

1. A rigid tunneling device for forming a passageway in subcutaneous tissue, said tunneling device comprising: an elongate shaft having a handle at a proximal end of the shaft; and a removable tip at a distal end of said shaft; Contains a vascular arteriovenous graft including a cannulated 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; an elongate tubular sleeve having a length and defining an internal lumen, said sleeve having a slit extending along a length of the sleeve from a proximal end to a midpoint of the length of the sleeve, said sleeve configured to be slidably positioned over at least a portion of said tunneling instrument between said handle and said tip; Contains 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 in place at the anatomical location; the lumen is configured to receive the distal end of the graft and at least a portion of the cannulation chamber through the proximal end of the sleeve, whereby the proximal end portion of the sleeve is configured to gradually expand along a slit to provide an enlarged diameter to accommodate the cannulation chamber; and A subcutaneous delivery system, wherein application of a longitudinal force to the sleeve from a distal end of the sleeve is effective to move the sleeve distally to remove the sleeve from tissue, thereby pulling the arteriovenous graft and the sleeve through a tunnel and causing the arteriovenous graft to be secured within the sleeve by radial compression of tissue around the sleeve to deploy a vascular graft.

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

15. The subcutaneous delivery system of claim 13 , wherein the sleeve is uniformly tapered from the proximal end to the distal end such that the distal end has a reduced diameter from the proximal end.

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

17. The subcutaneous delivery system of claim 13 , wherein the sleeve includes an enlarged diameter portion adjacent the proximal end, the enlarged diameter portion adapted to receive the cannulation chamber.

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

19. 14. The subcutaneous delivery system of claim 13, further comprising a clip including a pin, the shaft having a hole adjacent the tip defining an axial passage for receiving the pin to connect the shaft to the sleeve and apply a pulling force in a proximal direction.

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