WO2000071033A1

WO2000071033A1 - Refractor apparatus for use in harvesting mammary arteries during heart by-pass surgery

Info

Publication number: WO2000071033A1
Application number: PCT/US2000/013828
Authority: WO
Inventors: Richard S. Ginn; Michael C. Stewart; Michael V. Morejohn; Carol M. Lasalle
Original assignee: Cardiothoracic Systems, Inc.
Priority date: 1999-05-21
Filing date: 2000-05-19
Publication date: 2000-11-30
Also published as: AU5031900A

Abstract

Devices and methods for minimally invasive complete or partial harvesting of a vessel or vascular conduit from surrounding tissue, especially the saphenous vein for coronary artery bypass grafting, are disclosed. A system is disclosed for creating an expanded working space proximate a length of vessel to be harvested comprising an elongate tissue retractor (12) having distal and proximal ends, and at least one support structure (16, 18, 80) comprising a frame member (16, 18) having an open region (60) appropriately sized for the passage of endoscopic surgical instruments, a retaining portion (26) configured to be releasably fixed to the elongate tissue retractor (12) proximate the proximal end of the elongate tissue retractor (12), and a base portion (28) located opposite the retaining portion (26) of the frame member (16, 18). In preferred method of the present invention, a system in accordance with the teachings of the present invention is inserted into a working space proximate the length of vessel to be harvested. Once in place, the system is used to gently dissect overlaying tissue from the length of vessel and to create an expanded working space proximate the vessel. Surgical tools can then be inserted into the expanded working space through an open region provided in a support structure to completely harvest the length of vessel from the surrounding tissue.

Description

REFRACTOR APPARATUS FOR USE IN HARVESTING MAMMARY ARTERIES DURING HEART BY-PASS SURGERY

Field of the Invention

The present invention relates to surgical instruments and procedures for completely or 5 partially harvesting or dissecting tissue or vascular conduits from the body, and in particular, for the minimally invasive harvesting of vascular conduits for use as a bypass graft for coronary artery bypass surgery (CABG) or for peripheral vascular in situ bypass surgery.

Background of the Invention

For various surgical procedures, and most commonly for coronary artery bypass 10 grafting CABG), it is common to sever one end or completely remove ("harvest") a vascular conduit, such as an artery or vein, from its natural location in a patient's body and to use it elsewhere in the body. In CABG surgery, the vascular conduit is used to establish a bypass between an arterial blood source and the coronary artery being bypassed. Often, one or more of the saphenous veins in the legs or the radial arteries in the arms are used as the vascular 15 conduit. The saphenous vein is generally preferred by some surgeons in emergency situations and where multiple bypass conduits are needed. Alternatively, an artery proximate the heart, such as one of the internal mammary arteries (IMA) located along the chest wall or one of the radial arteries located in the forearms can be used as the bypass conduit. For patient's requiring multiple bypasses, a surgeon may use the saphenous vein and/or various arteries to 20 revascularize a patient's heart.

The conventional surgical procedure used to harvest the saphenous vein prior to its use, in a CABG procedure for example, may be very traumatic to the patient. The procedure involves making a continuous incision in the leg for the full length of the vein section to be removed in order to provide adequate exposure for visualizing the vein and for introducing

25 tools to sever, clip, cauterize, and/or ligate the branches of the vein. The incision must then be closed by suturing or stapling along its length. Major complications of the large wound such as skin loss or infections result in significant morbidity for approximately 1% of patients and frequently cause prolonged hospitalization. Other complications, such as impaired wound healing, saphenous nerve damage, hematomas, prolonged lymphatic drainage, fat necrosis

30 with cellulitis, and chronic edema, can occur at rates exceeding 20% and are particularly costly and traumatic for a patient who has also undergone cardiac surgery. Moreover, many patients who do not suffer major complications still experience lower extremity discomfort, often lasting 4-6 months or longer after the harvesting procedure. This harvesting procedure also leaves disfiguring scars, increases recovery time and the patient's hospital stay, and adds to the cost of the coronary artery surgery.

In an attempt to overcome these problems, less-invasive techniques for harvesting vessels have been developed. Most current, less-invasive techniques for dissecting a vessel employ a couple of small incisions, one at each end of the section of vessel to be removed. Blunt mechanical force is applied to first create a working space in the tissue surrounding the vein, followed by introducing tools to separate the vein from the surrounding tissue and to clip, cut, and/or cauterize side branches of the vessel. An endoscope is not necessarily required for such a procedure but may be used to enhance visualization of the vessel, the surrounding tissue, and working space without having to unduly stretch the patient's skin and tissue to visualize the working space at a distance from the incision.

A particular problem of minimally invasive harvesting procedures has been the inability of current systems to simply and effectively create a working space proximate the target vessel to be harvested. These endoscopic devices require the use of at least both hands of the operator and sometimes one or more additional assistants to effectively operate the devices. The working space provided is also extremely cramped and visualization of the vessel is extremely difficult, particularly at the distal extreme of the working space. These shortcomings often lead to longer operation times, decreased procedure efficacy and may result in significant trauma to the surgical site caused by extensive manipulation of the surgical tools within the working space proximate the vessel to be harvested.

Thus, minimally invasive vessel harvesting procedures could be improved with a single tool that creates an expanded working space proximate the tissue or vessel to be exposed during the dissection or harvesting procedure. Ideally, the tool could initially be inserted with a low profile that could subsequently be modified to expand the profile to create an expanded working space. Once the working space is provided, additional harvesting tools could then be inserted into the working space to free the tissue or vessel from the surrounding tissue.

Summary of the Invention

A preferred embodiment of the invention comprises a vascular access system comprising an elongate tissue retractor having distal and proximal ends and a length therebetween, and at least one support structure comprising a frame member having an open region appropriately sized for the passage of endoscopic surgical instruments. The at least one support structure includes a retaining portion configured to be positioned along the length of the elongate tissue retractor and to be releasably fixed to the retractor at a point or points along the length of the retractor, and preferably includes a discrete base portion located generally opposite the retaining portion of the frame member. The system may further include one or more additional support structures similarly configured to the at least one support structure described above and located opposite the at least one support structure proximate the distal end of the elongate tissue retractor. The system may also include tissue support rods to further expand the working space and to provide additional structural support to the system.

Additional features of a preferred system of the present mvention include lights or illumination sources to illuminate the workmg space during the performance of the surgical procedure.

In another preferred system of the present mvention, the elongate tissue retractor comprises a blunt dissection retractor, wherein the blunt dissection retractor comprises an elongate structure having distal and proximal ends, wherein the distal end is configured to dissect tissue overlaying a length of vessel to be harvested away from the length of vessel. In a preferred configuration of this system, the distal end of the elongate structure comprises a concave dissection hood. This preferred system may further include an endoscope passage extending between the distal and proximal ends of the elongate structure, the endoscope passage comprising a groove formed in an underside surface of the elongate structure extending from the proximal end of the elongate structure to substantially the distal end of the elongate structure, the groove including means for slidably receiving an endoscope; and an endoscope slidably disposed within the endoscope passage.

The present invention may also include additional tools suitable for freeing or exposing body tissue, particularly vascular conduits, and the use thereof consistent with the other devices and methods of the invention. Such tools may include a surgical clip applier, a surgical cutting tool, a bovie knife, a ligation instrument, and/or bipolar scissors slidably insertable through the open region of the at least one support member.

A preferred method for creating an expanded working space to expose a length of body tissue comprises: a) making a first surgical access incision through a skin surface to expose a first end of the length of body tissue to be exposed; b) creating an initial workmg space proximate an upper surface of the length of body tissue with a surgical instrument inserted into the first incision; c) providing an elongate tissue retractor having a distal and proximal end; d) advancing the elongate tissue retractor distally within the initial working space along the length of body tissue until the distal end of the elongate tissue retractor is located distally of a distal end of the length of body tissue to be exposed; e) pulling the proximal end of the tissue retractor away from the skin surface to further dissect tissue and skin overlaying the length of body tissue to create an expanded working space proximate the upper surface of the length of body tissue; f) providing at least one proximal support structure comprising a frame member having an open region appropriately sized for the passage of endoscopic surgical instruments, a retaining portion configured to be releasably fixed to the elongate tissue retractor, and a base portion located opposite the retaining portion of the frame member; and g) fixing the retaining portion of the proximal support structure to the elongate tissue retractor proximal of the first incision, the proximal support structure oriented between the skin surface and the elongate tissue retractor so that the base portion engages the skin surface.

In a preferred method of the above procedure the length of tissue to be exposed comprises a length of vessel, and the method comprises the additional step of h) harvesting the length of vessel using a surgical tool inserted through the open region in the proximal support structure and into the expanded working space proximate the length of vessel. The methods of the present invention may include the step of viewing the insertion and/or harvesting/access procedure with an endoscope.

Brief Description of the Drawings

FIG. 1 illustrates one embodiment of a vessel harvesting system of the present invention including a blunt dissection retractor comprising an elongate structure having a distal dissection hood. The system includes distal and proximal support structures releasably fixed to the blunt dissection retractor and also includes a plurality of tissue support rods configured to maintain a working space proximate to the tissue to be accessed and to reinforce the support structures and maintain them in a spaced apart and upright relationship.

FIG. 2 illustrates one embodiment of a vessel harvesting system of the present invention operatively positioned within a patient's leg for harvesting a saphenous vein.

FIG. 3 A is an enlarged view of the underside of the dissection hood of the present invention showing the endoscope lens apparatus and including a suction port for clearing the surgical field of excess tissue, blood, smoke, and other debris. FIG. 3B is an enlarged elevational view of the cross section of the elongate structure showing one means of slidingly receiving an endoscope within an endoscope passage comprising cooperating rail and dovetail structures.

FIG. 3C is an enlarged elevational view of the cross section of the elongate structure showing one means of slidingly receiving an endoscope within an endoscope passage comprising providing inwardly and downwardly sloping walls along the endoscope passage.

FIGS. 4(A-C) illustrate one embodiment of a support structure of the present invention. FIG. 4A is a front elevational view of the support structure. FIG. 4B is a side elevational view of the support structure and FIG. 4C is a perspective view of the support structure.

FIG. 5 illustrates alternate configurations of a support structure of the present invention wherem the support structure includes a plurality of snap-fittings for receiving tissue support rods.

FIG. 6 illustrates one embodiment of a vessel harvesting system of the present invention including a blunt dissection retractor comprising an elongate structure and a distal dissection hood. The system also includes distal and proximal support structures releasably fixed to the elongate structure using snap-fittings configured to releasably receive and hold the elongate structure and two tissue support rods.

FIG. 7 is a perspective view of a system of the present invention comprising first and second support structures, including an open region formed in the first and second support structures, and having tissue support rods extending between said first and second support structures.

FIG. 8 shows a system of the present invention, including a blunt dissection retractor, operatively positioned to expose the saphenous vein of a patient prior to dissection or harvesting of the vein.

FIG. 9A is a perspective view of an alternate configuration of a support structure of the present invention wherein the support structure includes a base portion having a sloped ramp upper surface for facilitating insertion of tools into an expanded working space created proximate the vessel to be harvested.

FIG. 9B is a side view of an alternate configuration of a support structure of the present invention wherein the support structure includes a base portion having a sloped ramp upper surface for facilitating insertion of tools into an expanded working space created proximate the vessel to be harvested.

FIG. 10 is a perspective view of one configuration of first and second support structures of the present invention wherein the support structures include a hinged mechanism for releasably receiving a blunt dissection retractor or similar elongate dissection or retraction tool.

FIG. 11 is a perspective view of a blunt dissection retractor which is suitable for use with a vessel harvesting system of the present invention.

FIG. 12 shows one system of the present invention wherein the blunt dissection retractor includes suture slots configured to receive a suture which.may be used to pull the retractor outwardly to expand the working space proximate the vessel length to be harvested. FIG. 12A is a perspective view of the system of FIG. 12 showing the unitary structure of the blunt dissection retractor and showing the suture slots. FIG. 12B is an underside view of the blunt dissection retractor of FIG. 12 showing an endoscope having a viewing portion disposed proximate the distal end of the endoscope, the endoscope slidingly disposed within an endoscope passage formed in the underside surface of the blunt dissection retractor. FIG. 12C is an elevational end view of the blunt dissection retractor showing the frontal configuration of the retractor. FIG. 12D is an elevational end view of the blunt dissection retractor showing the rear configuration of the retractor.

FIGS. 13 (A-D) show alternate configurations of the blunt dissection retractor-of

FIG. 12 operatively positioned proximate a length of tissue or vessel to be exposed wherein a suture is being used to pull the blunt dissection retractor outwardly to further expand the working space proximate the exposed tissue or vessel.

FIG. 14A shows the blunt dissection retractor of FIG. 13A wherein the system includes an external support structure configured to maintain tension on the sutures pulling outwardly on the blunt dissection retractor to expand the workmg space proximate the exposed tissue.

FIG. 14B is an elevational side view of the blunt dissection retractor of FIG. 14A.

FIG. 14C is a perspective view of the blunt dissection retractor of FIG. 14A showing the suture slot.

Detailed Description of the Invention The present mvention is devices, various assemblies of components, and methods for the minimally invasive harvesting of a section of a vessel from a patient's body. The section of vessel may be used, for example, as a coronary artery bypass graft. The following description of the present mvention is primarily directed to the minimally invasive harvesting of the saphenous vein, however, it is contemplated and should be understood that other vessels, such as the radial artery, and other vascular conduits may be harvested using the devices and procedures of the present invention. Another particular application of the present invention is for accessing a tissue portion for performance of peripheral vascular in situ bypass graft procedure. In such a procedure, a blood vessel is partially or completely freed from the surrounding tissue and used to revascularize ischemic tissue, muscle, or organ segment. For example, a peripheral vascular in situ bypass graft may be used to revascularize ischemic leg tissue in the lower extremities of diabetic patients. A saphenous vessel may be used as a source artery and is partially freed from the surrounding tissue and reconnected to a target vessel so as to redirect blood flow to the ischemic tissue area.

A preferred harvesting and vascular access system of the present invention and methods for its use will first be described with reference to the attached drawings. FIG. 1 shows a harvesting and vascular access system of the present invention comprising a blunt dissection retractor 10, a proximal support structure 18, and a distal support structure 16, wherein the proximal and distal support structures 18, 16 are fixed at proximal and distal portions of the blunt dissection retractor 10, respectively. The system of FIG. 1 also includes an array of tissue support rods 20. Each support rod 20 extends from a hole 22a provided in the proximal support structure 18 to a corresponding recess, slot or hole 22b provided in the distal support structure. The tissue support rods 20 run generally parallel to the blunt dissection retractor 10. A preferred system of the present invention includes at least one tissue support rod, such as a first tissue support rod 20a installed along one side of the blunt dissection retractor between the distal and proximal support structures 16,18. A plurality of support rods 20b, 20c may be provided as needed to support the system or isolate the harvesting site. Additional tissue support rod 20s (not shown) may be installed along the opposite side of the blunt dissection refractor to add further support to the system. As would be apparent to one of ordinary skill in the art, the support rods could feature several structural variations and shapes without altering the function relative to the support structures 16,18 and the retractor 10. Alternatively, the support rods may be omitted entirely without departing from the scope or teachings of the present mvention. The blunt dissection retractor 10 comprises an elongate structure 12 having a blunt dissection hood 14 fixed to the distal end thereof wherein the blunt dissection hood 14 is configured to bluntly remove surrounding tissue from about a tissue or vessel to be accessed or harvested or to bluntly separate tissue planes in a patient's body, ultimately to create a working space about the vessel or within tissue. The configuration of a suitable dissection hood 14 is described more fully in commonly assigned copending U.S. Pat. Application No. 08/878,653, incorporated herein by reference in its entirety. Preferably, the construction of the hood is such that an initial working space or tunnel can be bluntly created proximate the vessel or tissue to be accessed without the need for additional tools or devices. The blunt dissection retractor 10 also preferably includes a handle member 24 fixed to the proximal end of the elongate structure 12. The handle member 24 is configured to be easily and comfortably grasped to allow distal and proximal movement and manipulation of the blunt dissection retractor 10 relative to the operator.

One embodiment of a support structure of the present invention is best seen with reference to FIG. 4. The distal support structure 16 and proximal support structure 18 of the system are preferably identical structures comprising a frame member having a retaining portion 26 wherein the retaining portion 26 is configured to be releasably fixed to or to releasably receive and hold a portion of the elongate structure 12 of the blunt dissection retractor 10. The support structures 16,18 may also include a discrete base portion 28, at least a portion of which is disposed opposite the retaining portion 26. Base portion 28 includes at least one side wall 29 to define an open region 60. At least one of the distal or proximal support structures 16,18 may include an open region 60 sized to allow passage of instruments or visualization through the open region 60. The support structure may also include one or more slots or holes 22 which are configured to releasably receive one or more tissue support rods 20. The support structures 16,18 may be constructed from a variety of materials, including nylon, plastic, silicon, stainless steel, nitinol, polyurethane, or any other biologically compatible material having sufficient strength and rigidity. Similar materials may also be used for fabrication of the blunt dissection retractor and the tissue support rods 20.

FIG. 4 shows one embodiment of the present invention wherein the retaining portion 26 of the distal support structure 16 comprises a flexible clip which may be securely clipped to the distal end of the blunt dissection retractor 10 proximate the dissection hood 14. The elongate structure 12 of the blunt dissection retractor 10 includes a notched portion which is sized to engage the flexible clip of the retaining portion 26 and prevent the distal support structure 16 from moving relative to the blunt dissection retractor 10 once the distal support structure 16 has been clipped about the elongate structure 12. Alternatively, the retaining portion 26 may comprise a rail-and-groove structure (not shown) which cooperates with a mating rail-and-groove structure formed on the elongate structure 12. The retaining portion 26 may also comprise an open region (not shown) which is sized to frictionally engage the distal end of the elongate structure 12. The retaining portion 26 of the proximal support structure 18 may be configured similarly to the retaining portion 26 of the distal support structure 16 to securely engage the blunt dissection retractor 10 and prevent movement of the proximal support structure 18 relative to the elongate structure 12 of the blunt dissection retractor 10.

Alternate configurations of the support structures 16,18 are possible, several of which are shown in FIG. 5. Surgical indications, including patient size, the vessel or tissue to be exposed, the procedure(s) to be accomplished, the access site chosen, and physician preference largely dictate the most suitable support structure configuration for a given situation. For example, FIG. 5 A shows semicircular support structures 16, 18 wherein the space between first and second base portions 28 is open to allow access to the skin surface and to facilitate surgical access through the open region 60 of the support structure 16, 18. The retaining portion 26 of the support structure 16, 18 comprises a hinged retaining member 26b which may be securely latched so as to releasably receive the elongate structure 12 of the blunt dissection retractor 10. The support structure 16, 18 also includes a number of slots 22 which are configured to engage the tissue support rods 20 in a snap-fit fashion.

FIG. 5B shows an alternate configuration of a support structure 16, 18 of the present invention wherein the retaining portion comprises a snap fit fixture 26c similar to the slots 22 of the support structure 16, 18 of FIG. 5A. The snap fit fixture 26c of FIGS. 5(B-D) is configured to releasably receive an additional tissue support rod 20 in a system such as is disclosed in FIG. 7 wherein the blunt dissection retractor 10 is removed prior to installation of the system of the present invention.

In use, the blunt dissection retractor 10 is inserted beneath the skin and advanced along the vessel as described elsewhere herein. When the blunt dissection refractor 10 is at least partially advanced along the length of the vessel, one or more of the support structures 16,18 may be deployed along the length of the vessel. Generally, the support structures 16,18 are inserted beneath the skin, positioned between the vessel and the blunt dissection retractor 10, and oriented to rest immediately above the vessel and such that the base of the support structures 16,18 contact the tissue surrounding the vessel preferably at 2 or more points on either side of the vessel. In such a configuration, the support structures 16,18 are oriented in a position that is generally transverse to the length of the blunt dissection retractor 10. In this context, transverse orientation provides stability because the length of the support structures 16,18 that entered in a roughly perpendicular direction to the blunt dissection retractor is greater than the width of the blunt dissection retractor 10 at the point(s) engaged by the support structures 16,18, i.e., peφendicular to the length of; the blunt tissue retractor 10. As seen in FIG. 1 , in certain embodiments, the blunt dissection retractor 10 is adapted to receive and engage a portion of the proximal or distal support structure 16,18, however, the support structures 16,18 may simply be designed and oriented such that the blunt dissection refractor 10 rests upon a superior surface of the proximal or distal structure 16,18. In most instances, the proximal 18 and distal 16 support structures will be deployed independently, and may be deployed when the blunt dissection retractor 10 is completely or partially inserted beneath the skin and advanced along the vessel. Thus, one method of the invention involves introducing the blunt dissection retractor into an incision, advancing the blunt dissection retractor along a vessel, introducing at least one support structure, orienting that support structure to lie in a transverse fashion to the blunt dissection retractor 10, preferably substantially peφendicular such that a portion of the support structure engages the tissue proximate to the vessel on either side of the vessel, optionally inserting a second support structure spaced at a distance from the first support structure and similarly oriented generally transverse to the blunt dissection retractor. The foregoing steps may be conducted as part of the vessel harvesting procedures described in more detail herein.

The system of FIG. 1 may include an endoscope 40 which is accommodated within an endoscope passage (not shown) provided within the blunt dissection retractor 10. The endoscope 40 is preferably configured to be slidingly inserted into the endoscope passage 46 so that it may be slid distally and proximally to completely image the tissue surface located beneath the blunt dissection retractor 10. The endoscope 40 may be optical, digital, fiberoptic, or any of a number of well-known endoscope 40 types used for endoscopic visualization of surgical procedures. The endoscope passage 46 comprises a groove which is formed in the underside of the elongate structure 12 of the blunt dissection retractor 10 and extends from the proximal end of the elongate structure 12 to substantially the distal end of the elongate structure 12. The construction of a suitable endoscope passage is more fully described in U.S. Patent No. 5,817,013 to Ginn et al., incoφorated by reference herein in its entirety. FIG. 2 shows the system of FIG. 1 installed proximate the saphenous vein of a patient prior to harvesting. As shown in FIG. 3, the endoscope 40 includes a viewing portion 44 located at the distal end of the endoscope 40 which may comprise a charged coupled device camera (CCD camera), a fiber-optic viewing device, a digital camera, an optical viewing device, or any other appropriate viewing system well known in the art. As shown, the viewing portion 44 of the endoscope 40 is used to image the length of the saphenous vein located beneath the blunt tissue dissector. The viewing portion 44 is preferably turned substantially 30-45° from the endoscope 40 so that it images the portion of the saphenous vein which is directly beneath the endoscope 40. It may be desirable to turn the viewing portion 44 less than 30° so that the viewing portion 44 images the portion of the saphenous vein more advanced from the viewing portion 44. A chord 32 may be used to route the visual signal from a CCD camera, fiber-optic, digital, or other such viewing system to an external viewing source such as a television monitor. A power chord 30 is also included which provides power to the endoscope 40, light source, etc. Alternatively, an eyepiece (not shown) may be included to allow optical visualization of the harvesting procedure.

As seen in FIG. 3a, the viewing portion 44 of the endoscope 40 is disposed proximate the distal end of the blunt dissection retractor 10 and is slidably mounted within the endoscope passage 46 such that the viewing portion 44 may be disposed within a working space 48 created by a concave inner surface of the blunt dissection hood 14. The blunt dissection hood 14 creates a workmg space which is free of blood, debris, and tissue so that visualization is possible in a largely unobstructed visual field. The system of FIG. 3 A also includes suction ports 42 which are in communication with an external vacuum source via a vacuum lumen 42b. The suction ports 42 clear the visual field of smoke and debris which may be caused by harvesting of the saphenous vein, especially when a cautery knife is used.

FIG. 3B is an end view of the harvesting system of FIG. 3 A including a preferred means of mounting the endoscope 40 within the endoscope passage 46 wherein the endoscope 40 is slidably mounted on dovetail rails 52 provided along an upper surface of the endoscope passage 46. A number of alternative rail-and-groove configurations as well as other configurations well known in the art are suitable as means for allowing the endoscope 40 to slide distally and proximally while still securely holding the endoscope 40 within the endoscope passage 46 to allow stable and precise visualization of tissue located beneath the blunt dissection retractor 10. FIG. 3C shows one such configuration wherein the endoscope 40 is configured with a slightly outward cant 51 on each side which allows a secure fit between the endoscope passage 46 and the endoscope 40. This configuration may be desirable as it is easily sterilized for reuse.

A preferred method of the present invention will be described with reference to the system of FIGS. 1-3. It is first necessary to determine the conduit to be harvested, the location from which the conduit will be taken, and the length of conduit necessary. The method will be described with reference to the saphenous vein of a patient although it can be recognized by one skilled in the art that other body conduits, such as the radial artery, are appropriate for harvesting using the devices and methods of the present invention.

Although precise physiology may vary from patient to patient, the saphenous vein generally runs the length of the inner side of the leg from the ankle and terminates at the groin, where it enters the femoral vein. Prior to harvesting the saphenous vein for a coronary artery bypass procedure, typically the right or left saphenous vein is chosen for removal following preoperative examination of the legs of the patient. The total length of vein section required is determined by the number of coronary artery bypasses to be performed. A minimum length of 6 to 8 inches of saphenous vein is generally harvested for each bypass graft to be performed. On rare occasions, suitable segments of vein cannot be found in either leg and another vessel or vessels are used. In addition to the left and right internal mammary arteries, these other vessels may include, for example, the gastroepiploic artery, the radial artery in the forearm, and the cephalic vein from the wrist to shoulder.

For harvesting of the saphenous vein, the initial incision may be made in the ankle or groin region or above or below the knee. The saphenous vein has a larger diameter in the groin region and is less fragile above the knee than below the knee. However, some physicians and nurses prefer to make the initial incision at the ankle because of the ease in locating the vein, better exposure, a less crowded workspace, and a decreased chance of wound infection because of the distal location from the groin. Once an appropriate incision has been made in the desired access site, a blunt dissection retractor 10 of the present invention as shown in FIG. 1 is introduced through the incision and progressively advanced along the length of the saphenous vein. As the instrument is advanced, the blunt dissection hood 14 is used to separate the trunk of the saphenous vein from the surrounding connective tissue and skin.

Prior to advancement of the dissection retractor along the trunk of the saphenous vein, the endoscope 40 is preferably installed within the endoscope passage 46 and advanced distally within the endoscope passage 46 so that the viewing portion 44 of the endoscope 40 is disposed proximal to the workmg space 48 created within the inner concave surface of the dissection hood 14. As discussed above, the viewing portion 44 is thus provided a relatively unobstructed visual field which is free of tissue, blood, debris, and other undesirable visual obstructions. The surgeon can then view the advancement of the dissection retractor along the trunk of the saphenous vein and ensure that the dissection hood 14 tracks properly along the trunk. Visualization during the dissection process also allows the surgeon to verify that the upper surface of the vein is exposed and identify any side branches or connective tissue that may require separation from the vein.

The blunt dissection retractor 10 is advanced along the vein trunk until a suitable length of the vein has been freed of the overlaying skin and tissue. As noted above, an approximately 6-8 inch length of the vein is required for each bypass to be performed. The elongate structure 12 may include gradation markings indicating the length of vessel or tissue which has been dissected free of the overlaying connective tissue. Alternatively, the skin surface may be marked preoperatively so that it may be determined tactilely by the surgeon when the distal edge of the dissection hood 14 has reached the external skin mark, indicating that the system has dissected free a sufficient length of saphenous vein.

In a preferred method of the present invention, a second incision is made in the skin proximate the distal end of the tissue or vessel length to be harvested or accessed. For example, if the access incision to the saphenous vein is made at a location just above the knee of the patient, the second incision will be made in the thigh of the patient a selected distance away from the first incision (closer to the patient's groin). The second incision may be made either at the same time as the first access incision or it may be made after the blunt dissection retractor 10 has dissected an appropriate length of the saphenous vein free of the overlaying tissue. In the latter case, the surgeon will palpate the external surface of the patient's skin to precisely locate the distal end of the dissection hood 14. An incision is then made proximate the dissection hood 14 to allow the hood 14 to exit the incision. Once the distal edge of the dissection hood 14 is clear of the incision, the blunt dissection retractor 10 is advanced sufficiently so that the dissection hood 14 protrudes from the second incision.

In a preferred method of the present invention, it is not necessary that the blunt dissection retractor 10 completely frees the saphenous vein of the surrounding tissue during the step of advancing the blunt dissection retractor 10. It is only necessary to dissect the skin and tissue overlaying the saphenous vein sufficiently to create a working space proximate the upper surface of the saphenous vein having sufficient cross-sectional area to accommodate passage of the blunt dissection retractor 10.

Once the blunt dissection hood 14 is clear of the second incision, the distal end of the blunt dissection retractor 10 is gently pulled by the physician away from the leg surface. Movement of the distal end of the blunt dissection retractor 10 away from the leg surface causes a levering action wherein the skin is further dissected from the underlying tissue surface as additional connective tissue is separated or pulled free. The working space proximate the upper surface of the saphenous vein, which was formed by the initial insertion of the blunt dissection retractor 10 and possibly the ligation of side branches, is expanded as the distal end of the blunt dissection retractor 10 is pulled away from the leg surface to create an expanded working space between the upper surface of the saphenous vein and the lower surface of the blunt dissection retractor 10. The second incision should be of appropriate size and configuration to prevent tearing of the second incision as the working space proximate the upper surface of the saphenous vein is expanded.

After the tissue overlaying the saphenous vein has been expanded by movement of the distal end of the blunt dissection retractor 10 away from the surface of the patient's leg to create a working space of sufficient proportions, a first, distal support structure 16 such as shown and described in connection with FIG. 1 is attached to the distal end of the blunt dissection retractor 10 proximate the second incision as shown in FIG. 2. The retaining portion 26 of the distal support structure 16 is releasably fixed to the elongate structure 12 of the blunt dissection retractor 10 and the support structure 16 is manipulated so that the base portion 28 of the frame member contacts the surface of the patient's leg and maintains the distal end of the blunt dissection retractor 10 in a spaced relationship relative to the surface of the leg. The base portion 28 also serves to keep the bottom portion of the incision from caving in and interfering with the open region 60. In order to prevent slippage or movement of the distal support structure 16 relative to the leg surface, the base portion 28 may include means for fixing the support structure to the tissue surface, including a frictional surface such as a DeBakey serrated pattern, suction ports, hooks, barbs, or sutures. Alternatively, the distal support structure 16 may be sutured or glued to the skin surface to prevent movement of the system during the harvesting procedure.

As described above, the distal support structure 16 is oriented in a fashion substantially transverse to the length of the blunt dissection refractor such that the base portion 28 engages the tissue proximate to the vessel on either side thereof. As can be seen with reference to the figures and the foregomg descriptions, the design of the support structures 16,18 is generally such that the tissue above the vessel is raised along the axial length of the blunt dissection retractor and a narrow surgical field is created along a length of the vessel to be harvested, underneath or inferior to the blunt dissection retractor 10, between the support structures 16,18. As noted above, the width of the support structures, i.e., that portion which lies transverse to the blunt dissection retractor, preferably has a width greater than the blunt dissection retractor 10 and has a base portion 28 with a recessed region such that the vessel may lie within and traverse the base portion through the recessed region without being compressed by the base portion 28.

Following the installation of the distal support structure, the proximal end of the blunt dissection retractor 10 is similarly pulled gently away from the leg surface to expand the working space proximate the upper surface of the saphenous vein. The elongate structure 12 of the blunt dissection retractor 10 pulls the skin and tissue away from the saphenous vein and separates connective tissue so as to make an expanded working space proximate the upper surface of the saphenous vein. Once the proximal end of the blunt dissection refractor 10 is pulled sufficiently far from the surface of the leg, a second, proximal support structure 18 similar in structure to the first, distal support structure 16 is releasably fixed to the proximal end of the elongate structure 12 proximal the access incision in similar fashion as the distal support structure. Installation of the distal support structure 16 and proximal support structures 18 as shown in FIG. 2 maintains the blunt dissection retractor 10 in a spaced relationship relative to the surface of the leg such that an expanded workmg space is maintained between the upper surface of the saphenous vein and the underside of the elongate structure 12 of the blunt dissection retractor 10.

As shown in FIG. 2, a preferred harvesting system of the present invention includes a number of elongate tissue support rods 20 installed following installation of the distal support structure 16 and proximal support structure 18. The rods 20 are slid through a hole or slot 22a provided in a side portion of the proximal support structure 18 and then advanced through the expanded workmg space until and the distal end of the tissue support rod 20 may be inserted into a corresponding hole, slot, or recess in a side portion of the distal support structure 16. The tissue support rods 20 refract the skin and tissue to the side of the working space to provide additional clearance for the passage of tools into the expanded working space for the performance of the harvesting procedure. In a preferred method of the present invention, one or more rods 20 may be installed in one or both sides of the proximal and distal support structures 16,18. Alternatively, the rods 20 may be omitted entirely depending on the physician's preference and the size of the working space required.

After the system of the present invention is installed to form an expanded working space proximate the saphenous vein, the surgeon can then easily dissect the trunk of the saphenous vein clear of the surrounding leg tissue and at least some of the side branches by inserting one or more surgical instruments through the open region 60 provided in the distal or proximal support structures 16,18 and cutting the saphenous vein clear of the surrounding tissue and side branches in traditional fashion. For example, a cutting tool (not shown) may be inserted through the open region 60 into the expanded workmg space. The cutting tool severs the connective tissue surrounding the saphenous vein to free the main trunk from the surrounding tissue. When a side branch is encountered, a vessel ligation tool may be used to ligate the side branches and cut the trunk free of the side branches. Other tools (not shown) which may be inserted into the expanded working space through the open region 60 include clip appliers and bipolar scissors. Severing the side branches may also be accomplished with a cautery knife which both severs the side branch and cauterizes the vessel to prevent any loss of blood.

FIG. 6 shows an alternate embodiment of a harvesting system of the present invention subcutaneously positioned proximate a length of the saphenous vein to be harvested or dissected, wherein the system includes distal and proximal support structures 16, 18 having a retaining portion 26 comprising a hinged retaining member 26b which is configured to be latched about the blunt dissection retractor 10 so as to releasably secure the blunt dissection retractor 10 to the retaining portion 26 of the support structures 16,18. First and second tissue support rods 20 are also installed in snap-fit engagement with slots 22 provided on the distal and proximal support structures 16, 18. FIG. 10 shows a detailed view of a support structure 16, 18 showing the snap-fit engagement of the tissue support rod 20 and slots 22 provided on proximate an outer edge of the support structures 16, 18.

Many devices and methods are well known in the art for harvesting vascular conduits which are suitable for use with the teachings of the present invention. For example, an elongate clip applier (not shown) may be used to apply ligation clips to the side branches prior to severing the side branches to free the trunk of the saphenous vein from the surrounding tissue. The distal and proximal ends of the saphenous vein to be harvested are also ligated and severed to completely free the conduit from the surrounding tissue. Once the segment of the saphenous vein to be harvested is completely free and transected at both ends, the vessel section is removed from its native location and placed in a basin of heparinized saline or other preservative solution until the coronary bypass anastomoses are performed.

In a preferred method of the present invention, an endoscope 40 is used to image the harvesting process to assure a precise surgical removal of the vein segment and to prevent trauma to the surrounding tissue. As mentioned above, the endoscope 40 is slidably disposed within the endoscope passage 46 so that the endoscope 40 may be slid distally and proximally to precisely track surgical tools inserted through the open regions 60 in the support structures 16,18 and into the working space to free the saphenous vein from the surrounding tissue. The system of the present invention may include a light source, such as a fiber optic light cable which provides appropriate illumination and visualization of the surgical harvesting procedure.

In a preferred method of the present invention, surgical tools are inserted into the open space either through an open region 60 provided in the distal support structure 16 or through an open region 60 provided in the proximal support structure. For example, the open region 60 provided in the proximal support structure 18 may be used to free the portion of the saphenous vein which is located proximate the proximal end of the elongate structure 12. The open region 60 in the distal support structure 16 may be used for access to that portion of the saphenous vein which is located proximate the distal end of the elongate member. However, the choice of whether to access the saphenous vein through an open region 60 provided in the distal support structure, through an open region 60 provided in the proximal support structure, or from both the proximal and distal support structures 16,18, either sequentially or simultaneously, depends largely on the surgeon's preference and the clinical situation.

In order to provide additional clearance for the performance of the harvesting or access procedure, the handle member 24 and dissection hood 14 may be removable to allow better access to the open regions 60 and the expanded working space with the desired surgical tools. In a preferred method of the present invention, the endoscope 40 is removed and reinserted into the end of the elongate structure 12 opposite the support structure through which the surgical tools are inserted to harvest the length of vessel. This method is desirable in that it keeps the handle member 24 and chord 32 clear of the operating field, thus providing better access to the open region 60 of the support structure and expanded working space.

A distal support structure 16 is not required to practice the teachings of the present invention. For example, after the blunt dissection retractor 10 has created a working space proximate the upper surface of an appropriate length of saphenous vein to be harvested, the blunt dissection retractor is left in place within the working space without making a second incision. Then the proximal end of the blunt dissection retractor may be pulled gently away from the surface of the leg so as to extend the size of the workmg space and create an expanded working space. The vein is then harvested as discussed above. Although the working space proximate the distal end of the elongate structure 12 is somewhat more limited than the working space at the proximal end of the elongate structure 12, sufficient working space for harvesting of the vessel may be created by either advancing the distal end of the blunt dissection retractor 10 somewhat past the distal end of the length of saphenous vein to be harvested or by pushing the portion of the blunt dissection retractor 10 located proximally of the proximal support structure 18 inward toward the surface of the patient's leg so as to create a "see-saw" effect whereby the distal end of the blunt dissection retractor 10 is levered outwardly away from the saphenous vein. Tissue support rods 20 may also be installed as discussed above whereby the natural rigidity of the tissue support rods 20 relative to the proximal support structure 18 will prevent the skin located at the distal end of the blunt dissection retractor 10 from collapsing about the working space. Eliminating the distal support structure 16 may be desirable as it eliminates the need for a second incision, thus reducing patient trauma and eliminating the additional risk of post-operative infection posed by the second incision.

As discussed above, it is not required that the system of FIG. 7 include the distal support structure 16 to practice the teachings of the present invention. A simple blunt dissection tool 80 such as shown in FIG. 11 may be inserted in the first incision and advanced along the saphenous vein to bluntly dissect the overlaying tissue from the saphenous vein. The blunt dissection tool comprises a handle portion 86 fixed to a proximal end of an elongate member terminating in a bullet-shaped tissue dissector 82 at its distal end. After forming the initial working space or "tunnel" proximate the saphenous vein using the blunt dissection tool 80, a proximal support structure 18 may be releasably fixed directly to the shaft of the dissection tool 80. Additional tissue support rods 20 may also be installed through the proximal support structure 18 and extending distally to further retract the overlaying tissue from the saphenous vein and create an expanded working space proximate the length of saphenous vein to be harvested. In such a configuration, the natural rigidity of the rods 20 will hold back the surrounding tissue from the saphenous vein even at the distal ends of the tissue support rods 20. It is prefeπed that the tissue support rods 20 include an atraumatic distal tip in order to prevent trauma or accidental puncture of the skin when the skin is retracted away from the saphenous vein segment to be harvested. Alternatively, the distal tips of the support rods 29 may comprise functional aspects to facilitate harvesting. As such, rods 20 may function as both a harvesting tool and a support structure.

The teachings of the present invention are not limited to devices which bluntly dissect overlaying tissue from the upper surface of the vessel. For example, an initial working space may be formed proximate the upper surface of the length of saphenous vein to be harvested using a traditional cutting instrument which is guided, either tactilely or using an endoscope 40, along the saphenous vein so as to sever the connective tissue holding the overlaying tissue to the saphenous vein. One such system is disclosed in U.S. Pat. No. 5,373,840 to Knighton, the disclosure of which is incoφorated herein by reference in its entirety.

Once a suitable working space (or "tunnel") has been formed proximate the upper surface of the length of saphenous vein to be harvested, the cutting instrument(s) is (are) removed from the first incision and a elongate tissue retractor 70, preferably equipped with an atraumatic distal tip, is inserted into the working space in place of the cutting instrument. The elongate tissue retractor 70 is advanced along the length of vessel to be harvested until the distal end of the elongate tissue retractor 70 exits a second incision formed proximate the distal end of the segment of the saphenous vein to be harvested. The second incision is preferably prepared as discussed above in connection with the blunt dissection retractor 10.

In most respects, prefeπed methods of using this alternate system of the present invention is substantially similar to the methods discussed above in connection with a system having a blunt dissection refractor 10. As discussed above, the elongate tissue retractor 70 is used to the pull the skin and tissue overlaying the saphenous vein away from the upper surface of the saphenous vein by pulling outward on the distal and proximal ends of the elongate tissue retractor 70. Once the initial working space formed proximate the upper surface of the saphenous vein has been expanded to create an expanded working space, distal and proximal support structures 16,18 having retaining portions 26 configured to releasably connect to the elongate tissue retractor 70 are installed as discussed above. Figure 7 shows a system of the present invention wherein the blunt dissection retractor 10 of FIG. 1 has been replaced with a simple elongate tissue retractor 70. The alternate configuration of FIG. 7 may be desirable because of its simple, inexpensive design which provides a relatively large working space with a small silhouette having relatively few obstructions to interfere with the harvesting procedure. The system of FIG. 7 also includes a pair of tissue support rods 20 located on each side of the distal and proximal support structures. As shown in FIG. 7, the tissue support rods 20 and elongate tissue retractor 70 include handle means 72 located at the proximal end of the rods to facilitate installation of the rods. It is prefeπed that the distal ends of the tissue support rods 20 are securely fixed, for example, using a press-fit or threaded connection means, to the distal support structure 16 to ensure structural rigidity of the device.

The tissue support rods 20 may also include additional functions beyond merely holding back the overlying tissue from interfering with the expanded working space proximate the tissue to be exposed. For example, in the system of FIG. 7, the uppermost tissue support rod comprises a elongate tissue retractor 70 having the additional functions of alight bar having a plurality of light sources 21 aπayed along the length of the rod 20 so as to effectively light the expanded working space proximate the vessel or tissue to be dissected or harvested. The light bar 70 is provided with a light chord 73 connected to an external power source. The light sources 21 may be conventional electrical or fiber-optic sources depending on the desired performance of the light source 21. Alternatively, the light bar 70 may also include one or more vacuum ports (not shown) which remove smoke and debris from the expanded working space so as to maintain a clear field of view for performance of the surgical procedure. In another configuration, one or more tissue support rods 20 may include nozzles which are configured to provide fluid flow such as a saline mist to the working space to clear blood and debris from the surface of the tissue located underneath the harvesting system.

Alternatively, it is known in the art to bluntly dissect tissue from the saphenous vein by creating a working space proximate the length of the vein to be harvested using a blunt dissector on which is disposed an expandable member. The expandable member is inflated to expand the working space to create an expanded working space. The blunt dissector may also be deflated, advanced, and then reinflated to expose a greater length of vein for dissection or harvesting. As described above, a system of the present invention may then be inserted into the expanded working space to maintain the expanded working space for completing the dissection or harvesting of the exposed length of vein.

FIG. 12 shows one system of the present invention including a specially formed blunt dissection retractor 110 comprising an elongate structure 112 including suture slots 118 configured to receive a suture 112 which may be used to pull the retractor 110 outwardly to expand a working space proximate the vessel length to be harvested. FIG. 12A is a perspective view of the system of FIG. 12 showing the unitary structure of the blunt dissection retractor 110 and showing the suture slots 118. FIG. 12B is an underside view of the blunt dissection retractor 110 of FIG. 12 showing an endoscope 40 having a viewing portion 44 disposed proximate the distal end of the endoscope 40, the endoscope 40 slidingly disposed within an endoscope passage 46 formed in an underside surface of the blunt dissection retractor 110. FIGS. 12(C-D) are elevational end views of the blunt dissection retractor 110 showing the front (12C) and rear (12D) views of the retractor 110. As best seen in FIGS. 12( C-D), the elongate structure 112 of the blunt dissection retractor 110 includes lumens 42b for such functions as smoke evacuation; providing fluid flow for cleaning, treatment, etc. of the working space; or pressure sensing.

FIGS. 13 (A-D) show alternate configurations of the blunt dissection retractor 110 of FIG. 12 operatively positioned proximate a length of tissue or vessel to be exposed wherein a suture 120 is used to pull the blunt dissection refractor 110 outwardly to further expand the working space 120 proximate the exposed tissue or vessel. The particular configuration of the blunt dissection retractor 110 which is best suited for a particular procedure will likely depend on the clinical indications; including patient geometry, the size of the working space 120 required for performance of the procedure, the procedure to be accomplished, and the anatomical location of the procedure.

A prefeπed method of using a harvesting system as shown in FIGS. 12 and 13 requires that a working space 120 be provided proximate a length of vessel or tissue to be dissected or harvested as has been previously described. For example, the blunt dissection retractor 110 may be inserted at a first incision made proximate a first end of a vessel to be harvested. The blunt dissection retractor 110 then bluntly dissects along the length of the vessel to be harvested to form an initial working space. Alternatively, a separate dissection tool may be used to form an initial working space along a length of the vessel to be harvested, including a separate blunt dissection tool as shown in FIG. 11, a device as disclosed in U.S. Pat. RE 36,043 to Knighton et al, or a balloon dissection device as is known in the art.

Once an initial working space 120 has been formed proximate, for example, the vessel to be harvested, and the blunt dissection retractor 110 has been installed in the working space 120, a needle having a suture 112 attached is used to puncture the patient's skin proximate the suture slot 118 and the suture 112 is passed through the slot 118 as shown in FIG. 13. Tension is placed on the suture to pull the blunt dissection retractor 110 outwardly away from the vessel to be harvested so as to expand the working space 120 proximate the vessel. The tension on the sutures causes separation and dissection of the tissue layers to further expand the working space 120 to facilitate performance of the surgical procedure. In order to maintain appropriate tension on the suture 112 to maintain the expanded working space 120, it may be necessary for an assistant to manually hold the suture ends. Obviously, such a method is not the most desirable as a harvesting procedure may be time consuming and holding the sutures steady will become increasingly difficult throughout the procedure. Therefore, the present mvention comprehends an external structure which is configured to maintain constant pressure on the sutures to maintain the expanded working space during the performance of the surgical procedure. FIG. 14A shows such an external support structure 130 comprising a proximal frame 132, a distal frame 134, and tissue engaging pads 136. The frames 132, 134 include open regions 138 through which are passed the free ends of the sutures 118. The sutures 118 are then attached to suture winders 140 which are may be tightened or loosened by the operator to further tension or release the sutures 118 to adjust the size of the working space proximate the vessel to be harvested. The tissue engaging pads 136 may comprise gel pads or expandable pads which atraumatically contact the skin surface. The pads 136 may be made smaller to prevent undue obstruction of the surgical field.

Although the devices and methods of the present invention have been described in some detail by way of illustration and example, it will be readily apparent to those skilled in the art that certain modifications and other embodiments may be practiced without departing from the spirit and scope of the invention and which are within the scope of the appended claims.

Claims

Claims: We claim:

1. A vessel access system comprising: an elongate tissue retractor having distal and proximal ends and a length therebetween, at least one support structure comprising a frame member having an open region appropriately sized for the passage of endoscopic surgical instruments, a retaining portion configured to be releasably fixed to the elongate tissue retractor at a point along the length of the retractor, and a base portion located opposite the retaining portion of the frame member.

2. The system of claim 1 including at least one additional support structure comprising a frame member having a retaining portion configured to be releasably fixed to the elongate tissue retractor, and a base portion located opposite the retaining portion of the frame member; wherein said support structures are spaced apart along the length of the elongate tissue retractor.

3. The system of claim 1 further comprising: at least one tissue support rod comprising an elongate member having a distal portion and a proximal portion, wherein the proximal portion is configured to be releasably fixed to the at least one support structure so that the first tissue support rod extends substantially parallel to the elongate tissue retractor.

4. The system of claim 3 further comprising: a second tissue support rod comprising an elongate member having a distal portion and a proximal portion, wherein the proximal portion is configured to be releasably fixed to a proximal surface of the at least one support structure and opposite the first tissue support rod so that the second tissue support rod extends distally of the support structure substantially parallel to the elongate tissue retractor and first tissue support rod.

5. The system of claim 3 including a light source adapted to provide illumination to tissue surfaces located beneath the elongate structure of the of the blunt dissection retractor.

6. The system of claim 5 wherein the light source is disposed on the elongate tissue retractor.

7. The system of claim 5 wherem the light source is disposed on the at least one support structure.

8. The system of claim 5 wherein the light source is disposed on the at least one tissue support rod.

9. The system of claim 3 including at least one additional support structure comprising a frame member having a retaining portion configured to be releasably fixed to the elongate tissue retractor proximate the distal end of the elongate tissue retractor, and a base portion located opposite the retaining portion of the frame member, wherein the distal portions of the first and second tissue support rods are configured to be releasably fixed to opposite sides of a proximal surface of the at least one additional support structure.

10. The system of claim 3 wherein the distal portions of the first and second tissue support rods and the distal end of the elongate tissue refractor include handle means configured to allow manipulation of the first and second tissue support rods and the elongate tissue retractor.

11. The system of claim 1 wherein the elongate tissue retractor comprises a blunt dissection retractor, the blunt dissection retractor comprising an elongate structure having distal and proximal ends, wherein the distal end is configured to dissect tissue overlaying a length of vessel to be harvested away from the length of vessel.

12. The system of claim 11 wherein the distal end of the elongate structure comprises a concave dissection hood.

13. The system of claim 11 wherein the elongate structure includes an endoscope passage extending between the distal and proximal ends of the elongate structure, the endoscope passage comprising a groove formed in an underside surface of the elongate structure extending from the proximal end of the elongate structure to substantially the distal end of the elongate structure, the groove including means for slidably receiving an endoscope.

14. The system of claim 11 including an endoscope configured to be slidably inserted into the endoscope passage.

15. The system of claim 11 including at least one suction port located on an underside surface of the elongate structure, wherein the at least one suction port is in vacuum communication with an external vacuum source.

16. The system of claim 1 1 including a light source adapted to provide illumination to tissue surfaces located beneath the elongate structure of the blunt dissection retractor.

17. The system of claim 16 wherein the light source is disposed on the elongate tissue retractor.

18. The system of claim 16 wherein the light source is disposed on the at least one support structure.

19. The system of claim 1 including a surgical clip applier slidably insertable through the open region of the at least one support member.

20. The system of claim 1 including a surgical cutting instrument slidably insertable through the open region of the at least one support member.

21. The system of claim 20 wherein the surgical cutting instrument is a cautery knife.

22. The system of claim 1 wherein the at least one support structure is releasably affixed to the elongate tissue retractor proximate a distal end thereof.

23. The systems of claim 2 wherein the at least one support structure is affixed to the elongate tissue refractor at a distal end thereof and the at least one additional support structure is affixed to the elongate tissue retractor proximate to a proximal portion thereof.

24. A method for creating an expanded working space to expose a length of body tissue, the method comprising:

a) making a first surgical access incision though a skin surface to expose a first end of the length of body tissue to be exposed;

b) inserting under the skin surface an elongate tissue retractor having a distal end and a proximal end;

c) advancing the elongate tissue retractor along the length of body tissue;

d) introducing a support structure through the incision in the skin surface;

e) positioning the support structure between the skin surface and the elongate tissue refractor; and f) performing a surgical procedure at the exposed tissue.

25. The method of claim 24 wherein the surgical procedure is comprised of harvesting a length of vessel using a surgical tool inserted through the incision.

26. The method of claim 24 wherein the elongate tissue retractor comprises a blunt dissection retractor having an elongate structure and distal and proximal ends and including a concave blunt dissection hood fixed to the distal end of the elongate structure, the blunt dissection hood configured to bluntly dissect the length of tissue to be exposed from smrounding tissue wherein the steps of b), c) and d) comprise: inserting the blunt dissection hood into the first incision and advancing the dissection hood along the length of vessel to bluntly dissect tissue overlaying the length of vessel to be harvested from the length of vessel.

27. A method of harvesting a body vessel, the method comprising:

a) making a first surgical access incision though a skin surface to expose a first end of a vessel to be harvested;

b) creating a working space proximate an upper surface of the length of vessel with a surgical instrument inserted into the first incision;

c) providing an elongate tissue retractor having a distal and proximal end;

d) advancing the elongate tissue retractor distally within the working space along the length of the vessel until the distal end of the elongate tissue retractor is located distally of a distal end of the vessel to be harvested;

e) making a second surgical incision in the surface of the skin proximate the distal end of the of the elongate tissue retractor;

f) advancing the elongate tissue retractor distally until the distal end of the elongate tissue retractor exits the second incision;

g) pulling the proximal end and distal end of the elongate rod away from the skin surface to dissect tissue and skin overlaying the length of the vessel to create an expanded working space proximate the upper surface of the length of vessel;

h) providing proximal and distal support structures comprising a frame member having a retaining portion configured to be releasably fixed to the elongate tissue retractor and a base portion located opposite the retaining portion of the frame member, wherein at least one support structure includes an open region appropriately sized for the passage of endoscopic surgical instruments;

i) fixing the retaining portion of the proximal support structure to the elongate tissue refractor proximally of the first incision, the proximal support structure oriented between the skin surface and the elongate tissue refractor so that the base portion engages the skin surface;

j) fixing the retaining portion of the distal support structure to the elongate tissue retractor distally of the second incision, the distal support structure oriented between the skin surface and the elongate tissue refractor so that the base portion engages the skin surface; and

k) harvesting the length of vessel using a surgical tool inserted into the expanded working space proximate the length of vessel through the open region of the at least one support structure including an open region.

28. The method of claim 27 wherein the elongate tissue retractor comprises a blunt dissection retractor including an elongate structure having a distal and proximal ends and a concave blunt dissection hood fixed to the distal end of the elongate structure, wherein the steps of b), c) and d) comprise: inserting the blunt dissection hood into the first incision and advancing the dissection hood along the length of vessel to bluntly dissect tissue overlaying the length of vessel to be harvested from the length of vessel.

29. The method of claim 27 including the additional step of imaging the procedure with a endoscope.

30. The method of claim 27 including the additional step of imaging the harvesting procedure with a endoscope.

31. The method of claim 29 wherein the elongate structure includes an endoscope passage extending between the distal and proximal ends of the elongate structure, the endoscope passage comprising a groove formed in an underside surface of the elongate structure extending from the proximal end of the elongate structure to substantially the distal end of the elongate structure, the groove including means for slidably receiving an endoscope, the step of imaging the harvesting procedure with a endoscope comprising:

i) inserting an endoscope into the endoscope passage; ii) advancing the endoscope proximate to a point of interest along the length of vessel to be harvested; and

iii) visualizing the point of interest with the endoscope.

32. The method of claim 30 wherein the elongate structure includes an endoscope passage extending between the distal and proximal ends of the elongate structure, the endoscope passage comprising a groove formed in an underside surface of the elongate structure extending from the proximal end of the elongate structure to substantially the distal end of the elongate structure, the groove including means for slidably receiving an endoscope, the step of imaging the harvesting procedure with a endoscope comprising:

i) inserting an endoscope into the endoscope passage;

ii) advancing the endoscope proximate to a point of interest along the length of vessel to be harvested; and

iii) visualizing the point of interest with the endoscope.