Patent Application
20060095055
1. Field of Invention
The invention relates to the field of medical instruments, and more particularly, to a device for creating an incision in a hollow lumen, such as an artery or vein.
2. Description of Related Art
In many surgical procedures, a surgeon must make a substantially linear incision in a hollow structure having a lumen, such as a blood vessel. For example, the creation of an incision is generally the first step in creating a new blood flow path that bypasses a blockage or stenosis within an artery. In such a bypass procedure, a graft vessel, which can be a vein or an artery or a synthetic tube, is connected or anastomosed to the target vessel downstream the blockage or stenosis. The graft vessel acts as a conduit to take blood from its natural, unobstructed origin, and permit it to flow through the anastomosis to the target vessel at a location downstream of the original obstruction. Alternatively, the graft may be severed from its natural origin, and may be anastomosed to another, big blood vessel such as the aorta to take blood from. Where the bypassed vessel is a coronary artery, the procedure is known as coronary artery bypass graft (CABG) surgery. The connection made at the aorta is referred to as the proximal anastomosis and the connection or connections made at the coronary artery downstream of the obstruction is referred to as the distal anastomosis. The anastomosis can be end-to-side, requiring a side hole, generally made by a precise incision in the target vessel only, or can be side-to-side, requiring matched incisions in both the target vessel and the graft vessel.
A successful bypass graft creates blood flow to a previously blocked or substantially blocked artery. To maintain the new flow path, the anastomosis or connection between the graft vessel and the coronary or target vessel, must provide a smooth transition from the graft vessel to the target vessel. A poorly created incision may result in loose intimal flaps that create turbulence and obstruction with secondary thrombus formation at the anastomosis site, which in turn induces smooth muscle cell migration to the site as part of the body healing response. This healing response may lead to stenosis or a blocking of the anastomosis and associated artery. In addition, the incision must completely penetrate a portion of one side of the wall of the artery to create an opening without damaging any other tissue, such as the back wall of the artery near the site of the incision.
Further, the incision needs to be straight, uniform and of a defined length as the opening created by the incision is sized to communicate with the inner lumen of the graft vessel that the surgeon connects to the opening in the coronary vessel. This is particularly true when the surgeon uses an automatic anastomosis device to facilitate the creation of the anastomosis. In such a procedure, rather than hand sewing the graft vessel to the target vessel, the surgeon uses an anastomosis device or connector to make the connection. These connector devices can provide the benefit of a quicker, and potentially more reliable anastomosis, than a hand sewn anastomosis, even under limited access conditions. However, such connector devices are sized for a particular graft and target vessel and, as such, a particular incision length. Thus, it will be clear that a uniform, quality incision is desirable, whether the anastomosis is hand sewn or created with a connector, but an incision with a precisely defined, consistent length is even more desirable when the anastomosis relies on a connector.
The standard method for creating an incision in a cardiac vessel requires that the surgeon first pierce the vessel with a small scalpel to create a stab wound, for example using a scalpel having a 15 degree tip, like a Sharpoint® scalpel (Sharpoint Inc., Reading Pa.). The surgeon then may push the scalpel into the vessel lumen and enlarge the stab wound by cutting the vessel wall with the scalpel blade using an inside-out motion. During this step, the surgeon has to take particular care not to damage the back side of the vessel (referred to as “backwalling”). The surgeon then typically uses micro scissors to cut the arteriotomy to a desired length by extending the initial incision in one or both directions.
The creation of a uniform incision of a defined length is a difficult task when the surgeon uses a scalpel and micro scissors. As it is micro scissors generally do not make incisions of a consistent quality across the length of the incision they create. Practically, the incision created in the tissue cut near the tip of the micro scissors may often not be the same as the quality of the incision in the tissue cut near the pivot point of the micro scissors. Specifically, tissue cut at the tip of the micro scissors may be crushed, rather than neatly cut. This problem is caused at least in part because the cutting angle between the jaws of the scissors gradually decreases to almost zero near the tip as the cutting edges of opposing scissor blades assume a near parallel position during the cutting action, an issue intrinsically related to the pivotable nature of how a pair of scissors works. A small cutting angle stresses the mechanical parts of the micro scissors, and can lead to a failure to cut tissue.
To further complicate the procedure, where the surgery is performed on a beating heart, the surgical field is small, creating access issues that make it difficult for the surgeon to precisely manipulate the instruments, especially when attempting to anastomose to an artery on the posterior or inferior wall of the heart. Surgeons also do not typically have an accurate means of measuring the required arteriotomy size so it is difficult to precisely cut the intended length. Surgeons therefore rely on their subjective estimation of the desired arteriotomy length. The length of an arteriotomy created in this manner has been shown to be highly variable and inaccurate.
Where the surgeon determines that the length of the initial incision is too short, the surgeon will be required to lengthen the incision by again using micro scissors or a scalpel to cut the tissue. The use of these types of tools a second time creates the possibility that the resulting incision will not be aligned with the initial incision along with the attendant deficiencies of using the micro scissors discussed above.
Where a surgeon uses an anastomosis device, if the surgeon determines that the length of the incision is too long while performing an end-to-side anastomosis or a side-to-side anastomosis, then the surgeon can add additional stitches to close the remaining incision around the anastomotic device. This type of repair causes its own problems, as any additional suturing devaluates the benefit of an automated anastomotic system, requires access for carefully manipulated instruments, and last, but not least, may increase the likelihood of stenosis, due to a reduction in diameter or due to the body's healing response to an injury.
Where a surgeon hand sews an anastomosis, if the surgeon determines that the length of the incision is too long, especially while performing a side-to-side anastomosis where the graft vessel and the target vessel cross one another at an angle of 90° (a “diamond-shaped anastomosis”) and the graft vessel is anastomosed to more than one coronary artery (a “jump graft”), then the problem is more critical. Where this occurs, the surgeon is left with a difficult decision. Either suture the incision to shorten it and thereby risk diameter reduction and stenosis. Or, alternatively, connect the graft at the overly long incision, and risk that the graft vessel may flatten to accommodate the lengthy incision (the “seagulling” phenomenon), which may cause the graft vessel to effectively close off at the anastomosis site, thus putting both the current and all existing downstream both the current and all existing at risk.
The present invention addresses the shortcomings of the prior art by providing an improved device for creating an incision.
The described device is designed to create reliably and consistently a quality arteriotomy or venotomy, or incision in any other tubular natural or synthetic structure, of a defined length. An arteriotomy is an incision in the wall of an artery reaching the lumen, while a venotomy is such an incision in case of a vein. While the device is designed for use in human coronary arteries and arterial as well as venous bypass grafts during CABG, those skilled in the art understand the embodiments described herein have broader application in creating an incision in any hollow tissue structure, such as the intestines, the bladder, the ureter, other types of blood vessels, or other similar tubular structures.
According to the present invention, an device for incising a blood vessel includes at least one gripping portion, a stationary blade attached to the gripping portion that has a neck and a foot connected to the neck. The foot has a cutting edge along an upper surface. The device includes a relatively blunt moving blade having a leading edge and which is operatively movable with respect to the stationary blade. The moving blade has a first position, proximal to the upper surface of the stationary blade, and is movable to a second position, distal to the upper surface of the stationary blade, to cut tissue disposed between the upper surface of the stationary blade and the leading edge of the moving blade.
A method for making an incision in the wall of a hollow tissue structure that has an outer surface, an inner surface and a lumen, includes the steps of: (a) providing a device having a first blade, the first blade having a cutting edge along an upper surface, and a relatively blunt second blade having a leading edge, the moving blade being movable relative to the first blade from a first position, where the leading edge of the second blade is proximal to the upper surface of the first blade, to a second position, where the leading edge of the second blade is distal to the upper surface of the first blade; (b) incising the outer surface to create a small incision in the wall; (c) passing at least the cutting edge of the first blade through the small incision and into the lumen; and (d) creating a larger incision in the wall by using the first blade in cooperation with the second blade to cut from the inner surface to the outer surface when the second blade moves from the first position to the second position.
These and other features, advantages and benefits will be made apparent through the following descriptions and accompanying figures, where like reference numerals refer to the same features across the various drawings.
FIGS. 3(a)-(c) are, respectively, a top plan view, a side cross-sectional view of
FIGS. 5(a)-5(c) are alternate embodiments of the feet in accordance with the current invention;
FIGS. 6(a) and 6(b) are bottom views of the stationary blade and moving blade of vessel incisor of the current invention (not shown to scale so as to more clearly demonstrate the concepts);
FIGS. 8(a) and 8(b) are schematic views of the use of stationary blade depicted in
FIGS. 13(a)-13(d) are schematic views of the operation of the distal end of the vessel incisor according to the present invention;
FIGS. 15(a) and 15(b) are cross-sectional views of an alternate embodiment of the vessel incisor of the current invention;
FIGS. 18(a) and 18(b) are schematic views of embodiments of the vessel incisor of the current invention, each having a malleable portion;
Handle 30 has a proximal portion 31 designed to be grasped by the user and a distal portion 32 extending from the proximal portion at an angle A defined relative to a longitudinal axis L defined by the proximal portion of the handle. For the purposes of this application, “proximal” is defined as being closer to the surgeon's hand and “distal” is defined as being closer to the blood vessel incision site. Angling the distal portion 32 away from proximal portion 31 of handle 30 provides the surgeon with better visualization of the incision site when using vessel incisor 20. Preferably, distal portion 32 of handle 30 extends from proximal portion 31 at an angle A that ranges from approximately twenty (20) degrees to approximately ninety (90) degrees, but most preferably angle A is approximately forty-five (45) degrees.
Referring to
Vessel incisor 20 includes a stationary blade 40 for piercing the vessel wall and cutting the vessel wall from a position within the lumen. Stationary blade 40 is shown generally in
Referring to
Referring to
Shoulder 46 preferably has a width of approximately 0.5 mm, but in any event should be of a width that provides resistance to distal movement to the surgeon when neck 47 is disposed within the vessel puncture. In this way, shoulder 46 butts up against the adventitia or outer surface of the blood vessel and prevents foot 48 from unnecessarily contacting the inner surface of the blood vessel. As is shown in
Referring to
To more reliably cut tissue between moving blade 50 and cutting blade 40, the embodiments of vessel cutters 20 depicted in
Vessel incisor 20 also includes moving blade 50 that moves relative to stationary blade 40 to cut tissue disposed between moving blade 50 and stationary blade 40. The shape of moving blade 50 is a much less complex than the shape of stationary blade 40. Referring to
Distal end 53 preferably has a relatively blunt leading edge 53a, which is preferably ground and polished to have an angle that ranges from about 20° to about 5°, but is most preferably approximately 10° (relative to a standard flat or leading edge). The point of leading edge 53a is positioned nearer to bottom surface 53c than top surface 53b such that leading edge 53a of moving blade 50 resists and compresses tissue disposed between leading edge 53a and cutting edge 48a of stationary blade 40 to permit cutting edge 48a to cut or shear the tissue.
To maximize the effectiveness of the cut, leading edge 53a of moving blade 50 and cutting edge 48a of stationary blade 40 must maintain good point contact along the length of the cut. In one embodiment, depicted in
In use, when the surgeon uses device 20, and moving blade 50 is moved relative to stationary blade 40 between guides 44, 45, leading edge 53a presses tissue against cutting edge 48a of stationary blade 40, which cuts tissue disposed between the two blades with a shearing motion. Because cutting edge 48a of stationary blade 40 is sharper than leading edge 53a of moving blade 50, the stationary blade 40 cuts the vessel wall from the inside out, by cutting first the intimal layer of tissue, then the medial layer of tissue, and finally the tougher adventitial layer of tissue. In this way, the device first cuts the tissue on the inside of the blood vessel, which is softer than the tissue on the outer surface of the blood vessel. This is the preferred sequence from a surgical, as well as a biological point of view, since the vulnerable, delicate inner layers of the vessel are divided and fall aside before more force is required to cleave the much stronger outer layers. The “inside-out” cutting motion thus tends to avoid intimal crush and loose intimal flaps, which is important for anastomotic quality and the patency of the bypass graft.
Cutting the vessel wall from the inside out also greatly benefits from the use of the relatively blunt moving blade (or anvil) acting on the outside of the vessel, as this arrangement offers reliable tissue support during the cutting action, thereby minimizing stress on the surrounding vessel wall. In addition, by ensuring good contact between sharp stationary blade 40 and the anvil of moving blade 50 during the entire cutting action, optimal use of shearing force is made in addition to pure sharp cutting provided by cutting edge 48a, thereby increasing the quality of the cut and the reliability of device 20. The combination of a sharp blade and an anvil thus produces better cuts, without loose, frayed ends, as compared with a sharp blade used without an anvil.
Referring to
Referring to
As discussed above, it is important to ensure that device 20 creates an incision of a defined length. Referring again to
Vessel incisor 20 also includes actuator 60 for moving movable blade 50 relative to stationary blade 40. Actuator 60 includes a button 61 pivotably mounted to proximal portion 31 of handle 30 on a proximal end, a spring 63 disposed between button 61 and an inner surface 30e of handle 30, a slide 55 for moving in a longitudinal direction L, and a link 66 pivotably connected at a link proximal end to the distal end of button 61 and on a link distal end to slide 55. Referring to
In this manner, as shown in
When the surgeon depresses button 61 against spring 63, the distal end 61b of button 61 pivots toward upper surface 30d of handle 30, thereby causing link 66 to pivot relative to button 61 and move distally within path P. This movement effectively lengthens link 66 relative to the longitudinal direction L, which in turn pushes slide 55 and moving blade 50 from their proximal positions to their distal positions through path P. Moving blade 50 is shown in its distal position in
When the surgeon releases button 61, button 61 returns to its first position under the force of spring 63, thereby returning link 66 to its initial position, and slide 55 and moving blade 50 to their proximal positions. As slide 55 moves proximally, moving blade 50 also moves proximally with respect to stationary blade 40, thereby again ready to be used to create an arteriotomy.
An important consideration when using device 20 is to ensure that the distal end of is held steady when actuating moving blade 50. In this regard, handle 30 is designed to substantially separate the action of holding device 20 from the action of actuating device 20 so as to stabilize the instrument during actuation. Handle 30 permits the surgeon to hold device 20 in two positions to reduce or dampen tremors felt by the working or distal end of device 20 by stabilizing device 20 in the surgeon's hand. The surgeon may either hold device 20 with the palm of his or her hand in a prone (palm down) position or a supine (palm up) position. With reference to
When device 20 is held in the supine position, the surgeon employs device 20 such that blades 40, 50 act at a location between the surgeon's hand and body. As such, the surgeon has the added advantage of being able to clearly view the incision site while positioning the distal end of device 20. In particular, the surgeon can clearly view the target vessel while making the puncture and passing foot 48 of stationary blade 40 through the puncture and into the lumen of the vessel. In the supine position, the surgeon rests proximal portion 31 of handle 30 on either the index finger or both the index finger and middle finger with the palm facing the underside of the device, presses either the index finger and middle finger, or the middle finger and ring finger against a separate one of flats 33 on either side of button 61, and actuates button 61 with the thumb.
Whichever position the surgeon chooses, prone or supine, he or she may further stabilize device 20 by resting his or her arm on a stable point in the operating space, such as a retractor. In this manner, device 20 may be actuated while being held stably, thereby further minimizing the likelihood that the surgeon will inadvertently cut tissue.
Referring to FIGS. 13(a) through 13(d), the steps of using device 20 to pierce and then cut the vessel wall V are depicted graphically. Once the surgeon determines an appropriate location on a vessel, the surgeon manipulates handle 30 to position distal portion 32 of device 20 with respect to the vessel. As is shown in
Once foot 48 is within the vessel lumen, as depicted in
As a result of the means by which the incision is formed, incision I created by vessel incisor 20 is largely independent of any measuring or cutting techniques; instead, the incision is dependent upon the length of cutting edge 48a. Thus, the length of the arteriotomy is controlled by the distance between tip 48d and neck 47, otherwise referred to as the horizontal length of the foot. In the preferred embodiment shown in
Referring to
This inventive design is in contrast to a more typical prior art arteriotomy device, where the actuation force is typically in line with the cutting action, and therefore the user may inadvertently cut tissue by the cutting blade. It is important to avoid inadvertent cutting as to do so might create an incision of the wrong length. As discussed above, precise incisions are necessary when employing automatic anastomotic devices to connect bypass grafts to blood vessels.
Further, when foot 48 of device 20 is disposed within the blood vessel, shoulder 46 butts up against the adventitia or outer surface of the blood vessel and prevents foot 48 from unnecessarily contacting the inner surface of the blood vessel. Shoulder 48 also serves to steady device 20 when actuation force F is applied to button 61.
In an alternate embodiment depicted as device 120 in
A second alternate embodiment is depicted as device 220 at FIGS. 15(a) and 15(b), and includes a moving blade 250 formed to eliminate the need for actuation button 61 and spring 63. In this embodiment, moving blade 250 is disposed within and constrained by handle 230. Moving blade has a proximal portion 250a which is retained within the proximal portion of handle 230, a middle portion 250b, connected to proximal portion 250a, bent to be disposed outside handle 230 in a slot formed in handle 230, and a distal portion 230c which acts in concert with stationary blade 240 to cut blood vessel tissue as described above. Moving blade 250 is actuated by pushing on middle portion 250b, which straightens moving blade 250 within handle 230 to extend distal portion 250c distally relative to stationary blade 140 and cut tissue disposed therebetween.
A third alternate embodiment, depicted as device 320 at
In a fourth embodiment, depicted as device 420 at
A fifth embodiment is depicted as devices 520, 620 in FIGS. 18(a) and 18(b), wherein proximal portion 531, 631 of handle 530, 630, can be connected to end effector 532, 632 by intermediate portion 533, 633. Intermediate portion 533, 633 may be malleable so as to permit the surgeon to actuate moving blade 550, 650 from a position remote of the incision site. For example, when anastomosing an artery on the posterior or inferior wall of the heart, it may be difficult for the surgeon to access the preferred incision site. Devices 520, 620 permit the surgeon to position proximal portion 531, 631 on one side of the heart, and then bend intermediate portion 533, 633 such that end effector 532, 632 is appropriately positioned to incise the vessel.
Alternatively, intermediate portion 533, 633 may be designed so as to permit device 520, 620 to be actuated from a position outside the chest cavity. In either case, intermediate portion 532, 632 may be designed similarly to the flexible connector described in U.S. Patent Application No. 60/551,609, filed on Mar. 9, 2004, a ball-and-socket type shaft as described in U.S. patent application Ser. No. 09/492,558, filed on Jan. 27, 2000, or of the type described in U.S. patent application Ser. No. 10/736,199, filed on Dec. 15, 2003 (Attorney Docket No. ETH 5099), the disclosures of which are hereby incorporated by reference.
The embodiments shown in FIGS. 18(a) and 18(b) are substantially similar. Each device 520, 620 includes a stationary blade 540, 640 and a moving blade 550, 650 that moves relative to stationary blade 540, 640 to cut tissue between the blades as described in connection with the above embodiments. Proximal sections 531, 631 of the embodiments each contain an actuator button 561, 661 pivotably connected to a link 566, 666, which in turn is pivotably connected to a slide 555, 655 that moves through a defined pathway within proximal sections 531, 631 and acts against a spring 563, 663.
The embodiments of FIGS. 18(a) and 18(b) differ primarily in the design of the end effector 532, 632 and how they are actuated. Slide 555 of device 520 is connected to a semi-rigid rod 567 at the proximal end of rod 567. Rod 567 is movable within a sheath 568, and may be a plastic rod or a wound coil spring or any other device having a stiffness that permits rod 567 to be pushed within sheath 568. Slide 655 of device 620 is connected to a cable 667 at the proximal end of cable 667. Cable 667, like rod 567, is movable within a sheath 568, and may be a plastic rod or a wound coil spring. Cable 667, however, does not need to have a stiffness that permits cable 667 to be pushed within sheath 668.
End effector 532 includes a slide 534, which is operatively connected on its proximal end to the distal end of cable 567, and on its distal end to movable blade 550. End effector 632 also includes a slide 634 that is operatively connected on its distal end to movable blade 550. End effector 632, however, also includes a link 633 which is operatively connected on one end to the distal end of cable 667, is pivotable about a pivot point P attached to the housing of end effector 632, and is pivotably connected on its other end to slide 634. Link 633 is also connected to a spring 635 which supplies a force that biases slide 634 and therefore moving blade 650 in their proximal, initial positions. An alternate means of connecting end effector 532, 632 is to connect the distal end of sheath 567, 667 to the housing of end effector 532, 632 via a connector 537, 637. Connector 537, 637 permits end effector 532, 632 to rotate or articulate or both relative to sheath 567, 667 so as to position end effector 532, 632 at different orientations.
Referring to
A sixth embodiment is depicted as device 720 in perspective in
As with prior embodiments, device 720 includes an actuator 760 that has a button 761 pivotably mounted to proximal portion 731 of handle 730, a spring 763 (shown schematically) disposed between button 761 and an inner surface 730e of handle 730, a slide 755 for moving in a longitudinal direction, and a link 766 pivotably connected at a link proximal end to the distal end of button 761 and on a link distal end to slide 755. Slide 755, however, is formed as a proximal part of a cylindrical coupling that is rotatably coupled to a connector 756 which acts as the distal part of the cylindrical coupling. Connector 756, in turn, is connected to moving blade 750. Slide 755 and connector 756 are slidable as a unit within a path molded within handle 730. The path may extend between proximal portion 731 and distal portion 732.
Thus, as with earlier embodiments, moving blade 750 is moved relative to stationary blade 740 when button 761 is depressed as slide 755 and connector 756 act as one unit to slide within the path. The surgeon, however, has the option of rotating distal portion 732 relative to button 761 and proximal portion 731 to better access the planned incision site. Coupling 733 may include detents (not shown) so that distal portion 732 can be rotated in predetermined increments. Coupling 733 may also include a lock (not shown) to lock distal portion 732 with respect to proximal portion 731 prior to actuating device 720.
Specific construction details that are not shown are believed to be within the purview of those of ordinary skill in the art. The present invention has been described herein with reference to certain preferred embodiments. These embodiments are offered as illustrative, and not limiting, of the scope of the invention. Certain modifications or alterations may be apparent to those skilled in the art without departing from the scope of the invention, which is defined by the appended claims.
