JPH0355133B2 - - Google Patents

Description

Claim 1: The blade support comprises a blade support and a leader, and the blade support has a blade at its front end that is elongated so as to pass smoothly through the vein and has an exposed cutting edge toward the intended direction of movement. , the leader is formed into an elongated body for smooth passage through the vein, and a first rod is connected to the front end of the leader, and the leader is configured to cut the front end of the blade support so as to draw the blade support through the vein. The central portion of the edge and the rear end of the leader are connected via a second rod, which allows the blade support, which is connected to the leader, to be inserted into a pair of leaflets of the venous valve as it is pulled through the vein. A venous valve cutting device characterized by making an incision. 2 The front end of the blade support is formed with a pair of curved protrusions that extend forward from both ends of the cutting edge of the blade, so that when cutting and passing through the vein, the venous valve leaflets are aligned with the cutting edge. 2. The cutting device according to claim 1, wherein the cutting device is prevented from slipping through. 3. The cutting device according to claim 1, wherein the leader and the rods connected to the front and rear of the leader have torsional rigidity sufficient to manually rotate the direction of the blade within the vein. 4. The leader is an elongate body with a first rod coupled to its forward end and a blade support coupled to its rear end via a second rod to center the cutting device during movement within the vein. A cutting device according to claim 1. 5. The first rod, the second rod, and the connecting portion thereof are flexible and have torsional rigidity sufficient to manually rotate the direction of the blade within the vein. Cutting device as described in section. 6. The cutting device according to claim 1, wherein the connection between the leader and the blade support is removable. 7. The cutting device according to claim 1, further comprising valve closing means for closing the venous valve when the blade of the blade support approaches the venous valve. 8. The valve closing means comprises a catheter attached to the rear end of the blade support for passage into the vein following the blade support, the catheter being adapted to release fluid into the vein. Range 7th
Cutting device as described in section. BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to the use of a valve cutting device for in situ preparation of a vein for an arterial lateral canal. Regeneration of blood vessels in the lower extremities that can lead to ischemia has long been a problem for surgeons. Impairment of arterial blood flow to the lower extremity due to narrowing of the artery due to compression or disease creates a condition that, if not corrected, can eventually lead to amputation of the lower extremity. Various surgical techniques have been devised to bypass damaged or obstructed arteries to restore circulation to the lower extremities. A brief survey of the surgical procedures available today reveals the limitations of current technology. Historically, the use of inferior knee arteries as outflow channels for bypassing occluded nearby arteries has been a well-established surgical entity. The use of the saphenous vein in situ as a conduit for bypassing a failing artery allows for the formation of a viable endothelium that does not cause traumatic systemic damage and for the size of the bypassed artery. It is ideal in theory since it fits well and thus facilitates anastomosis. Furthermore, since the taper is gentle, the flow properties are optimal. However, a major obstacle in directing blood flow in the veins from the heart to the extremities is the presence of valves in the veins.
Venous valves are adapted to allow blood to pass freely in the direction of the heart, but to block or prevent blood flow in the opposite direction. Most commonly, each valve consists of two opposing leaflets whose opposing edges meet to interrupt the flow of blood or fluid away from the heart. Several methods have been devised to prevent this venous valve function, such as cutting out part of the blood vessel and reversing its position, and using artificial blood vessels made of synthetic materials. , and removal or destruction of the ductus venosus. All of these have been tried in actual practice, and some results have been obtained. The first of these methods to be attempted was the cutting and inversion of the saphenous vein. This technique is still commonly used and remains the standard by which alternatives are evaluated. Strict preservation of the endothelial lining of veins harvested during vascular surgery is clearly one of the most important factors in determining the degree of patency subsequent to bypass procedures. Vein walls are extremely vulnerable to factors such as handling, toxic drugs, and interruption of blood flow, and respond to highly localized stimuli by undergoing severe and prolonged occlusion.
Even with strict attention to the details of vein collection, preparation, and storage, endothelium detachment occurs within minutes. It takes 24 weeks for this endothelium to finally recover. The degree of patency of excised and everted venous branches decreases rapidly during the first 6-12 months, probably as a direct result of the initial endothelial damage. The need to obtain native vessels lined with normal endothelium led to the idea of using the saphenous vein in its native location. One of the first attempts to incapacitate venous valves was to destroy the valves. Although this technique was originally suggested and used more than 20 years ago, results have not been consistent and, at best, inferior to those obtained by saphenous vein inversion. As a result, by the 1970s the method had virtually ceased to be used. The use of synthetic venous tubes has been controversial. Early attempts used Dacron, but its use was quickly abandoned due to high failure rates in the thigh-to-knee position. After this, the use of newer, non-native materials, such as polytetrafluoroethylene, was reported, but this too was accompanied by unexpected and even quite opposite results. The use of venous prostheses has one limited but significant advantage, namely for patients who do not have a healthy saphenous vein available as a bypass. However, this does not occur frequently in patients requiring arterial bypass. A method known as valve cutting was developed around the same time that attempts were made to destroy valves. Although valve cutting has produced good and harmonious results, it has not gained acceptance in the United States for various reasons. The valve dissection concept utilized in the present invention was first developed by the present inventor in 1974 as a means to prepare the saphenous vein in situ as an arterial bypass. Preparation of the saphenous vein for this purpose involves, in principle, the removal of valvular obstruction to distal arterial blood flow, and the removal of a branch of the vein that becomes an arteriovenous fistula when the vein is arterialized. It involves interruption of the tube and mobilization of its ends to form an anastomosis of the proximal and distal arteries. The technical challenge is to achieve these with a minimum of surgical operations. The simplest, most convenient, and least traumatic method of disabling bivalve venous valves is to preserve the lobule in a functionally closed position by fluid flow from above or by pressure from arterial blood. while cutting them in the longitudinal direction. This is the essential point of the valve dissection technique. The valve dissection performed prior to the present invention involved introducing scissors of various lengths through a proximal incision in the saphenous vein, closing the valve leaflets by influx of fluid, and then closing the valve leaflets with the scissors. Consists of cutting. The valve below the mid-femoral region is incised through this route. Other valves are very easily dissected using a valve dissector that cuts through each leaflet sequentially by a retrograde path through the distal incision. This "in situ" method appears to be ideal due to the excellent safety of the endothelium and vessel wall during treatment. There are two main types of instruments currently available for performing valvotomy: (1) scissors with smooth tips and narrow handles and (2) valvotomy devices. There are some restrictions when using each type. Visualization of the valve site is necessary because scissors or valve dissectors can be easily and accidentally introduced into side branches present at any valve site, causing lacerations in the venous vessel wall. Visually inspecting each valve during surgery is extremely time consuming.
The longer a vein loses its blood supply, the greater the risk of endothelium damage. Therefore time is of the essence. There are also restrictions on the insertion of the various types of instruments. Smooth-tipped scissors can only be extended from the proximal phlebotomy site to mid-thigh. Other valves must be incised by introducing a valve dissector through a side branch at the appropriate location or through an incision made distal to the valve location. This can result in multiple lacerations along the venous vessel wall and a concomitant increase in the area of injury. Said method is tedious, time-consuming and requires great surgical skill, thus severely limiting the in situ use of the saphenous vein. The inventor's valve dissector below is simple and requires less time and skill. The aforementioned constraints have resulted in the development of the present invention. The valve cutters used to dissect the valve leaflets are made from non-toxic and inert materials. Its components include a leader sufficiently rounded to prevent damage to the venous vessel walls, housed in a protective support, and tapered to facilitate passage up and down the interior of the vein without damaging the endothelium. a cutting blade made of a valve cutter, and a leader having a torsionally rigid but flexible rod communicating with the cutting blade; A first hole is provided to provide a mounting point for an extension rod used to extend the extension rod. The support of the cutting blade is provided with a second hole that allows suturing of the valve disconnector to the catheter, which acts as a conduit for fluid to flow into the vein during the actual cutting procedure. The pressure of this fluid forces the valve leaflets into a closed position so that the leaflets are effectively engaged by the cutting blades. This method of using a valve cutter involves exposing both the proximal and distal portions of the vein and artery to be used as a bypass. A proximal incision is made into the vein and the first two valves are cut with smooth tipped scissors while holding them in the closed position. A distal incision is made and the rod is inserted superiorly into the vein until it exits the proximal cut site. A valve cutter is attached to this rod and the entire device is pulled down along the vein. Fluid from the catheter keeps the leaflets of the valve closed during the cutting procedure. The valve dissector is then returned to the proximal incision, the valve dissector is removed, and the rod is removed from the distal incision. The remaining distal valve is cut using a valve cutter inserted through the distal incision or a side branch of the vein. The inventor's valve cutter for said method has the following advantages: it eliminates the need to visually inspect each valve site; it eliminates the need to inadvertently introduce the valve cutter into a side branch of the vein and cause a laceration; There is little risk of causing damage; there is little risk of tearing the venous wall;
Also, no large shearing or frictional forces are applied to the extremely weak endothelium. Most importantly, the present invention allows for the use of the saphenous vein in situ in many cases where this is not currently possible. As a result, much satisfactory revascularization of lower extremities at risk of blood occlusion is expected with a concomitantly improved preservation rate of the lower extremities.

[Brief explanation of drawings]

The invention will be more fully understood from the following description taken in conjunction with the accompanying drawings. FIG. 1 is a top view of the valve cutter of the present invention in combination with a leading central device and a trailing catheter. FIG. 2 is a side view of the valve disconnector of the present invention. Figure 3 shows the invention in intravenous use.

[Detailed description of the invention]

FIG. 1 shows an assembly of parts used in the present invention. This combination comprises a blade support 10 with a leader 1 and a blade 7. These two members will be referred to below as a valve disconnector 4 as a whole. Also shown in the assembly of FIG. 1 is a catheter 14. The leader 1 is shaped with sufficient taper to facilitate passage through the vein with minimal risk of damage to the delicate endothelium. A means for attaching the leader 1 to a first rod 5 is provided by a first threaded hole 2 provided in the front end 3 of the leader 1 and extending inward a certain distance. The first rod 5 should be flexible, but should have sufficient torsional stiffness to allow controllable rotation of the valve disconnector 4. A first rod 5 extends from the distal vein laceration and can be manually rotated to change the angle of the cutting blade 7. Also, the first rod 5
form a means for moving the valve cutter 4 downwardly along the vein so that the valve leaflets are cut. A second flexible and sufficiently torsionally rigid rod 6 connects the rear end 8 of the leader 1 and the cutting edge 9 on each side of the cutting blade 7 and is coupled to the cutting blade support 10. can be done. The cutting blade support 10 also has sufficient taper to minimize contact with the venous vessel wall. It is important that the valve leaflets do not slip off the cutting blade 7. Cutting blade support 10
extends forwardly from the cutting edge 9 to form a curved protrusion or guard 11 with sufficient inward curvature to prevent such slippage.
Guard 11 also serves to prevent the venous vessel wall from coming into contact with cutting edge 9. A second hole 12 in the rear end 13 of the cutting blade support 10 is provided for attachment of the catheter 14 with suture material 15. The materials used for the construction of the parts of the valve disconnector 4 may be of any suitable type suitable for the purpose mentioned and preferably inert and non-toxic. The dimensions of the valve cutter 4 are limited only by the size of the vein used for bypass. The blade 7 is housed in the blade support 10 in any conventional manner. For example, support 10 may be molded from any suitable material such that blade 7 is securely mounted therein. As seen in FIG. 2, the forward or cutting end of the blade support 10 is tapered relative to the guard 11 from the rearmost end 30 of its blade opening.
This taper serves to facilitate passage of support 10 through a vein or valve to be severed. Detailed Description of Valve Preparation for Bypass A very useful aid in the implementation of this procedure prior to surgery is the constant use of venography. This accurately captures the anatomical variations often seen with this vein. If these deformities are not identified, the surgical workup will be incomplete and largely ineffective, leading to failure or abandonment of the procedure, and a greater depression below the knee with the patient standing prior to the procedure. The course of the veins is marked on the skin.
This involves introducing pressure waves proximally into the dilated vein by tapping or rubbing and checking whether the subcutaneous location of the vein is too deep by using the pressure waves propagated by palpation or Doppler ultrasound probing. This is done by detecting. Simultaneous distal and proximal exposure of both arteries and veins can be performed by a two-team technique. The distal venous vein is exposed at the level of the anticipated distal arterial anastomosis by an incision parallel and posterior to the location of the vein determined above. Its size is determined by in situ comparison with a catheter of known size or by measurement with a sterile vernier. A minimum diameter of 2.5 cm is considered preferred. Completely disconnect the saphenofemoral junction valve from the proximal incision. The second valve is 3-5 cm from the proximal incision and the third valve is 10 cm directly or spaced from the medial subbranch. These valves are confirmed by slightly distending the vein through the proximal incision with intravenous solution. These valves are cut with smooth-tipped scissors. The plane of the valve leaflet is usually parallel to the skin. In actual practice, a rod or Fogartry catheter is introduced into the saphenous vein below the knee through a distal incision 21 made in one of the side branches and a proximal incision 18.
Pass proximally through and emerge. Any rod 5 that maintains sufficient torsional rigidity to allow rotational movement of all instruments relative to the valve leaflets 22 may be used. The rod 5 is attached to the valve disconnector 4 through a first threaded hole 2 provided in the leader 1. Then the face of the cutting blade 7 is placed against the closing face of the valve 17 to be cut.
Turn the valve cutter 4 at 90° and slowly pull it down along the vein. At the same time, intravenous fluid 23
is introduced through catheter 14 through proximal incision 18. The fluid 23 is regulated at a pressure of 200 mmHg by a plastic bag-like fluid infusion cuff containing the fluid 23. This pressurized injection urges each successive valve into the closed position so that the leaflet 22 is effectively engaged by the cutting blade 7.
Catheter 14 is secured to second hole 12 by suture material 15.
It is attached to the valve disconnector 4 through the valve disconnector 4. The valve cutter 4 is advanced towards the knee if the vein is large enough to accommodate it and then the proximal incision 18 is
through and removed. The first rod 5 is removed through the distal incision 21 and the other valve is cut by a valve dissector introduced through the distal incision 21 or a venous branch. Although the present invention has been particularly illustrated and described by its preferred embodiments, it will be apparent to those skilled in the art of surgery that this invention departs from the true spirit and scope of the invention as defined by the appended claims. It will be understood that various changes in form and detail may be made without modification.