19. Describe: the posterior wall technique (BrJPS 1981; 34:47), the cuff technique (BrJPS 1981; 34:50), the sleeve technique (Ann PS 1984; 13:145).
Answer:
The posterior-wall or posterior-wall-first technique is a microvascular anastomotic technique where the posterior wall is sewn first. The first suture is placed through the vessel ends in the middle of the posterior wall. The second and third sutures are placed on either side of the first suture very close to it so that the intervening spaces are hemostatic. The fourth and fifth sutures are placed anteriorly to the second and third sutures. One end of each of these sutures is left long to facilitate placement of the sixth and seventh sutures. One end of each of the sixth and seventh sutures is left long so that the anterior wall of the anastomosis can be held up for placement of the eighth and usually final stitch which should be equidistant from the sixth and seventh ones. The advantages of this technique are: it allows clear visualization of the posterior wall and lumen; it makes end-to-side anastomoses more easily performed; the most difficult sutures are placed first; and finally, it is faster and less cumbersome than the old anterior-wall-first technique.
The cuff technique is a way to reduce the number of sutures needed to perform a microvascular anastomosis thereby reducing trauma to vessel tissue while still achieving hemostasis and maintaining patency. After completion of an anastomosis, a cuff of autogenous vascular tissue is placed directly around the anastomosis and fixed into position with two or more sutures which incorporate adventitia only. In a rat model, use of these cuffs were shown to have shorter times to hemostasis and equally high patency rates compared to anastomoses without cuffs.
The sleeve technique essentially inserts the end of the feeding vessel into the receiving vessel of the flap and, by overlapping them, avoid the possibility of a blood jet causing intimal dissection of the receiving vessel. If the vessels are equal in size than only two sutures are needed for the anastomosis. If the feeding vessel is smaller than three sutures are needed. The technique should not be used if the feeding vessel is larger. After both vessel ends have been clamped, dilated, irrigated, and gently but maximially dilated, the first suture is passed with a longitudinally-oriented bite into the wall of the feeding vessel without entering the vessel lumen. The suture is placed at a distance from the cut vessel end of approximately one and a half times the vessel diameter and then passed through the receiving vessel from inside to out. This first suture should be left long and untied until the second suture is placed at 180 degrees away in the same manner. Both sutures are then tied. These sutures are only meant to hold the vessel ends together and not to pull one inside the other so the feeding vessel stump will be folded on itself. Using microforceps, the receiving vessel should be lifted midway between the sutures and the folded stump should be gently manipulated without gripping the end (to avoid tearing it) so that it straightens out and points into the receiving vessel. Once the feeding vessel stump is inserted, it should be probed to make sure the inserted vessel is fully inside, and not kinked. When three sutures are used, they should be placed 120 degrees apart with the first two sutures tied and the folded stump straightened out prior to placement of the third suture. Care must be taken to avoid distorting the vessel or cause further pulling by placement of the third suture. This technique should be used at the distal end of arterialized vein interposition grafts. Poorer patency has been observed when the technique has been modified so that the feeding vessel is dragged by the sutures into the receiving vessels. The technique is thought to be advantageous in that it takes less time to perform and decreases the risk of intimal separation or aneurysm formation at the anastomosis.