Читать книгу Complications in Equine Surgery - Группа авторов - Страница 153

The importance of meticulous and proper placement of ligatures is essential for healing and preventing surgical complications. Whether it is open surgery or laparoscopy, ligatures are placed for the same reasons; however, there may be differences in the mechanics of the procedure [28]. Effective surgical techniques when performing ligation and vessel occlusion for hemostasis are essential in prevention of unnecessary hemorrhage [26].

Suture needs to be of sufficient size to withstand the tensile forces placed on the loop and shear forces at the knot. Regardless of the knotting technique used, the use of monofilament suture is recommended because it appears to be stronger and provides more efficient hemostasis then multifilament suture [30]. Monofilament suture is also advised for laparoscopic ligating loops because the shape of the loop is usually maintained reasonably well by the increased stiffness [28, 29]. Ligature loops should be tied table‐side rather than pre‐tied and sterilized because sterilization can weaken the suture material and predispose to ligation failure [28]. A 4‐S modified Roeder knot using monofilament suture is recommended for maximal ligature loop strength [28].

The performance of the single knot loop has been shown to be biomechanically superior to a double knot loop in tensile breaking strength because with the single knot loop the forces are equally divided over the whole ligature, whereas with a double knot loop the two loops of the ligature will have different tensions after every knot [27]. A transfixation ligature can be performed to prevent slippage of the ligature; however, postoperative bleeding may still occur due to ligature failure of one of the double knot loops [27]. Sliding knots have been shown to be quicker and behave similar to or better than a surgeon’s knot in establishing hemostasis of arteries [30].

Tissue bulk can be overcome by dividing it into smaller sections (“divide and conquer method”) or multiple ligatures can be placed around a bulky structure to improve the hemostasis [26]. Clamping to crush the tissue and reduce its bulk, as well as “flashing” the clamp adjacent to the ligature being placed, are additional techniques for improving vessel occlusion and ligature security [26].