This invention relates generally to biomedical systems and methods. More specifically, the invention relates to systems and methods for harvesting a vessel section.
Heart disease, specifically coronary artery disease, is a major cause of death, disability, and healthcare expense in the United States and other industrialized countries. A common form of heart disease is atherosclerosis, in which the vessels leading to the heart are damaged or obstructed by plaques containing cholesterol, lipoid material, lipophages, and other materials. When severely damaged or obstructed, one or more of the vessels can be bypassed during a coronary artery bypass graft (CABG) procedure. CABG surgery is performed about 350,000 times annually in the United States, making it one of the most commonly performed major operations.
To prevent rejection, the graft material is preferably a blood vessel harvested from elsewhere within a patient's body. The most frequently used bypass vessel is the saphenous vein from the leg. Because the venous system of the leg is redundant, other veins that remain within the patient's leg are able to provide return blood flow following removal of the saphenous vein.
Various methods have been used to harvest the saphenous vein. Until recently, the typical procedure involved making a single long incision that overlies the entire length of the vein, extending from a patient's groin to at least the knee and often to the ankle. This method results in substantial postoperative pain, with patients frequently complaining more of discomfort at the site of the leg vein harvesting than of pain from their CABG surgery wound. In addition, such an extensive incision site is subject to infection and delayed healing, especially in patients with poor circulation, which not infrequently accompanies coronary artery disease. The disfiguring scar from such a large incision is also of concern to some patients.
Less invasive procedures are preferred, and surgical devices and techniques now exist that allow the saphenous vein to be harvested through one or more small, transverse incisions along the length of the vein, generally using an endoscope. Endoscopic procedures yield reduced wound complications and superior cosmetic results compared with traditional methods of vein harvesting. However, this procedure requires considerable manipulation of the vein, has a high conversion rate when visualization is obscured by bleeding or the procedure is taking too long and often requires stitches to repair the vein following harvest. Further, it is generally tedious, time consuming, and relatively complex, requiring extensive accessory equipment and a substantial learning curve for the surgeon.
Some embodiments of the invention provide a vessel tensioning handle for use with a cutting device and a cannula for harvesting a section of a vessel. The handle can include a housing adapted to be coupled to the cutting device and a bobbin assembly positioned within the housing. The handle can also include a vessel tensioning tape wrapped around the bobbin assembly. The handle can further include a tensioning device member coupled to the vessel tensioning tape. The tensioning device member can be adapted to be coupled to the cannula. The cannula can be coupled to the vessel. The vessel tensioning tape can place tension on the section of the vessel as the cutting device is advanced over the vessel.
Embodiments of a vessel harvesting method of the invention include making a first incision at a proximal end of the section of the vessel, and making a second incision at a distal end of the section of the vessel. The method can also include inserting a cannula into the proximal end of the vessel, and securing the proximal end of the vessel to the cannula. The method further includes coupling a vessel tensioning tape to the cannula, applying tension to the vessel, and advancing a cutting device over the vessel.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention.
In one embodiment, the distal end of the vessel tensioning cable 1010 can be coupled to a proximal end of a tensioning device member 861, as shown in
In one embodiment, as shown in
In one embodiment, as shown in
The vessel can be kept taught in order to not allow the vessel to start to migrate forward with the handle 1000 as this subjects the vessel to bunch, which can lead to cutting the main portion of the vessel. The vessel tensioning cable 1010 is used to hold the vessel in position while the cutting tubular member 1002 is advanced over the vessel. In some embodiments, this tensioning function can improve the quality of the harvested vessel.
In the drive and release system 1030, push buttons 1034 can be pressed together by the operator to release a nut 1038 from a thread 1024 for free movement of the cutting tubular member 1032 along the thread 1024. In one embodiment, a vessel stabilization channel can traverse through the thread 1024. Clockwise rotation can advance the drive and release system 1030 along the thread 1024. The pitch of the thread 1024 and the angle of rotation can determine the travel distance. Counterclockwise rotation can reset one or more pawls 1036 on the nut 1038 to prepare for the next advance. Counterclockwise rotation can also provide a second swipe of the cutting tubular member 1032 across the tissue before the next advance. The pawls 1036 can be spring loaded against the nut 1038. The pawls 1036 can be disengaged for manual operation.
Some embodiments of the invention include a vessel tensioning handle that applies a substantially constant tension to a vessel being harvested from the surrounding tissue during a harvesting procedure. Some embodiments of the vessel tensioning handle can be operated by a clinician with a single hand. The tension that is applied to the vessel during the harvesting procedure can be of sufficient force to hold the vessel close to its original (i.e., native, pre-harvest) position, while at the same time minimizing damage to the vein during the harvest procedure.
The brake handle 2050 can be coupled to the first housing 2060 and the second housing 2070 by the brake handle 2050 receiving circular bosses of the first housing 2060 and the second housing 2070 within corresponding circular recesses on each lateral side of the brake handle 2050. The brake handle 2050 can pivot about the circular bosses in order to move the brake 2090 until the brake 2090 engages and holds the vessel tensioning tape 2170 between the brake pad 2120 and the brake 2090. The brake spring 2010 biases the brake pad 2120 toward the brake 2090 and the brake handle 2050.
A distal end of the vessel tensioning tape 2170 can be coupled to the socket cannula adapter 2110. The socket cannula adapter 2110 can include a ball socket that receives a ball of the ball cannula adaptor (or tensioning device member) 2100, which can allow the ball cannula adapter 2100 and the cannula 851 (as shown in
Some embodiments of the invention provide a vessel tensioning handle including a snap-back mechanism designed to substantially reduce or eliminate the rapid and/or uncontrolled retraction of the vessel tensioning tape back into the handle. Such release can occur, for example, when the pulling tension is released, e.g., when the vessel tensioning tape detaches from the vessel being harvested, or when the brake in the handle releases while the vessel tensioning tape is unattached. In some embodiments, the snap-back mechanism includes a weighted arm and a balance spring that can act to protect a harvested vessel in the event of an uncontrolled retraction of the vessel tensioning tape back into the handle.
As discussed above, the spring 2650 holds the arm 2640 in position until the rotational speed of the bobbin assembly 2620 reaches an upper limit, at which time the arm 2640 locks with the teeth 2630. However, if the upper limit it not reached, the snap-back mechanism 2600 will not be activated, and the entire length of the vessel tensioning tape 2170 can be used during the vessel harvesting procedure.
A catheter is introduced into the vessel section over the previously placed guidewire (Block 420). A proximal portion of the vessel section is secured to the catheter (Block 425), for example by suturing the vessel onto a barb positioned adjacent to the proximal end of the catheter. Alternatively, the catheter can be introduced into the vessel without a guidewire being previously placed.
The guidewire (if present) is withdrawn (Block 430), and a rod can be inserted into the catheter to stiffen the vessel section (Block 435). Both the catheter and the rod can be attached to a removable handle (Block 440). The handle can carry a tubular cutting device, or the cutting device can be introduced over the handle after the handle has been attached to the catheter and rod. An inner lumen of the cutting device provides a close-sliding fit for the handle. The tubular cutting device is thus oriented coaxial with the rod and with the vessel section to be harvested (Block 445).
The cutting device is then advanced over the vessel section to core out the vessel section and tissue adjoining the vessel section (Block 450). The cutting device can be advanced by either pushing or pulling the device over the vessel section. Where the cutting device comprises two tubular members, one positioned within the other, the two tubular members can be advanced separately. For example, inner tubular member 120 can be advanced first to hold the vessel and surrounding tissue, while outer tubular member 110 is advanced second to cut the tissue being held by the inner tubular member. The process of incrementally advancing the inner tubular member and then the outer tubular member is repeated until the entire section has been excised. Advancing the inner tubular member ahead of the outer tubular member can protect the walls of the vessel from the cutting element(s) positioned on the outer tubular member. Advancing and rotating the inner and outer tubular members separately can also protect the side branches of the vessel by holding them in place to achieve a clean cut at a sufficient length. The cutting device, for example, can be twisted first in one direction and then in the other direction, or it can be rotated over the vessel. The outer and inner tubular members can be twisted in opposite directions to provide a scissoring action.
The cored out vessel section and adjoining tissue are removed from the body of the patient (Block 455). Either before or after removing the vessel section and adjoining tissue, a hemostatic control method for branch vessels severed as a result of coring out the vessel section can be introduced through either the first or the second incision. The hemostatic control method can be, for example, a biological sealant, e.g., platelet gel that can be prepared from the patient's blood and injected or otherwise introduced along the track of the cutting device. The hemostatic control method can also be a thrombogenic substance such as fibrinogen, fibrin and/or thrombin placed in the track left by the cutting device. Alternatively, or in combination with a biological sealant, a biocompatible or biodegradable tube can be enclosed within the cutting device to be delivered as the cutting device is advanced over the vessel or after the cutting device has completed coring out the vessel and adjoining tissue. The tube exerts pressure on the cut branch vessels and can be either removed or, in the case of a biodegradable tube, left to dissolve or degrade over a period of a few days, for example. The space left after the removal of the vessel can also be filled with gauze to provide internal pressure to limit bleeding and absorb blood. The gauze can be removed periodically to check for absorbed blood. Limited blood collected on the gauze indicates the wound bleeding has diminished.
Hemostatic control methods are not required for embodiments of the invention as the tubular cutting device itself can exert pressure on the cut branch vessels while it remains within the patient's body. A drain can be inserted at the end of the harvesting procedure to deal with any bleeding that does occur. The site of the vessel harvesting procedure, e.g., the leg of a patient, can also be wrapped with a compression bandage to limit bleeding.
In an alternative method of the invention, a rod is inserted directly into the vessel. Thus, no guidewire and/or catheter is used. In one embodiment, a proximal portion of the vessel can be attached to the rod rather than to the catheter as described above. The handle is then attached to the rod.
In another alternative method of the invention, the catheter is inserted directly into the vessel. Thus, no guidewire or rod is used. In one embodiment, the catheter includes one or more inflatable structures, such as balloons. In yet another alternative method of the invention, no catheter or rod is used; only a guide wire is used.
A cutting device is oriented coaxially with the cannula, the balloon, and the vessel section to be harvested (Block 446). The cutting device is then advanced over the vessel section to core out the vessel section and tissue adjoining the vessel section (Block 450). The cutting device, for example, can be twisted first in one direction and then in the other direction, or it can be rotated over the vessel. The cored out vessel section and adjoining tissue are removed from the body of the patient (Block 455). Either before or after removing the vessel section and adjoining tissue, a hemostatic control method for treating branch vessels severed as a result of coring out the vessel section can be introduced through either the first or the second incision. The hemostatic control method can be, for example, a biological sealant, e.g., platelet gel that can be prepared from the patient's blood and injected or otherwise introduced along the track of the cutting device. The hemostatic control method can also be a thrombogenic substance such as fibrinogen, fibrin and/or thrombin placed in the track left by the cutting device. Alternatively, or in combination with a biological sealant, a biocompatible or biodegradable tube can be enclosed within the cutting device to be delivered as the cutting device is advanced over the vessel or after the cutting device has completed coring out the vessel and adjoining tissue. The tube exerts pressure on the cut branch vessels and can be either removed or, in the case of a biodegradable tube, left to dissolve or degrade over a period of a few days, for example. The space left after the removal of the vessel can also be filled with gauze to provide internal pressure to limit bleeding and absorb blood. The gauze can be removed periodically to check for absorbed blood. Limited blood collected on the gauze indicates the wound bleeding has diminished.
The site of the vessel harvesting procedure, e.g., the leg of a patient can be wrapped with a compression bandage to limit bleeding following vessel harvest. For example, a compression wrap specifically designed to apply direct pressure over a wound created by a device of the invention might be used. Such a compression wrap has a compartment, such as a pocket, to house a tubular object such as a tube, rolled gauze, rod, hemispherical tube, or the like. When the wrap is secured onto a patient's leg, this tubular/semi-tubular object is positioned directly over the wound, and bleeding is controlled. Thus, hemostasis is achieved. In one embodiment, the wrap is made out of an elastic material, such as neoprene, and can include hook and loop closures or similar such enclosure system so that an appropriate pressure is applied to the patient's leg once it is enclosed by the wrap. When open the wrap lies flat, so that it can be placed under the patient's leg prior to the vessel harvesting. Immediately following vessel harvest, the compression wrap with tubular object is positioned onto the patient's leg, making sure that the tubular object is placed directly over the wound so that direct pressure to the wound can be applied.
It will be appreciated by those skilled in the art that while the invention has been described above in connection with particular embodiments and examples, the invention is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein.
Various features and advantages of the invention are set forth in the following claims.
This application claims priority under 35 U.S.C. §119 to U.S. Provisional patent application Ser. No. 60/852,020, filed on Oct. 16, 2006, the entire contents of which is hereby incorporated by reference.
Number | Date | Country | |
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60852020 | Oct 2006 | US |