Flipping and Recruitment of Instrumentally Tied Knots as a Means of Saving Suture Material

This is the authors' abstract. We don't add key points for this paper.

Sir: The trick of economic use of atraumatic sutures lies in the use of the needle holder for tying,1 and in the technique of flipping the knot's first throw to allow for recruitment of additional functional length. Flipping means to relocate the knot from one strand (or end) of the suture to the other.2 The techniques of flipping and recruitment are explained as follows. When an atraumatic suture is tied instrumentally, the armed working end of the suture is wrapped around the needle holder before the nonarmed end of the suture is picked up in the instrument's jaw (Fig. 1, left). As the first throw slides from the needle holder to encircle the nonarmed end, the latter becomes the standing part of the knot (Fig. 1, center). Without change of this configuration, the standing part would be pulled to allow the knot to slide down to the tissues to be approximated or ligated (Fig. 1, right). This would lead to waste of most of the length of the suture, in casu the nonarmed standing part that is cut after the knot has been tightened.Fig. 1.: (Left) A knot's first throw of an atraumatic suture is instrumentally tied by wrapping the armed working end around the needle holder before the nonarmed end of the suture is picked up in the instrument's jaw. (Center) The nonarmed end becomes the knot's standing part when the first throw slides from the needle holder to encircle it. (Right) Subsequent tightening of the resulting loop without flipping of the knot to the other end would lead to waste of most of the nonarmed length of the suture.To prevent such waste, the knot has to be flipped. Consequently, the armed end of the suture becomes the standing part that is pulled while the knot is tightened (Fig. 2, left). If, in addition, the throw around this standing part is kept loose enough and actively guided toward the standing part, the nonarmed (now working) end of the suture is allowed to run around this standing part. This way, extra length of the nonarmed end may be recruited for the standing part (Fig. 2, center). Thus, maximal length is saved for additional suturing (Fig. 2, right), allowing up to 30 interrupted skin sutures composed of a surgeon's knot and an additional half-hitch to be tied out of one 45-cm atraumatically armed 4 × 0 suture.Fig. 2.: (Left) To prevent waste of suture length, the knot has to be flipped from one end of the suture to the other. This is accomplished by asymmetric pull on the armed strand and guidance of the nonarmed end toward the knot. (Center) Keeping the throw around the now standing part loose enough, the now working end is run around the pulled standing part to allow for additional length of the nonarmed end to be recruited as part of the armed end. (Right) Thus, minimal length of the suture is used for the actual knot and maximal armed length is saved for additional suturing.The simplest examples of flipping knots are the half-hitch and the double-overhand knot that is commonly used as the first throw of a surgical knot.2,3 Both also allow easy recruitment of additional length. Once tightened, both knots are best converted to a flat knot to prevent slipping, and additional throws are then used to secure the knot. Some instrumentally tied surgical knots do not have a flat configuration but may be flipped to save suture length anyway.4 With these knots, it is generally harder to save additional suture length by recruitment because of friction between both strands. If a knot cannot be flipped at all, material waste can only be prevented by pulling the suture as far as possible through the tissues before tying it. In 1994, Revington and Bowyer calculated that a 10 percent saving of suture materials may represent an economical saving of £10,000 (or |CE15,000 or $20,000).1 Given the current prices of these materials and the even more economical suturing technique presented here, these savings can be manifold today. This may be something to reckon with every time we pick up our needle holder. DISCLOSURE The author has no financial interest to declare in relation to the content of this article. J. Joris Hage, M.D., Ph.D. Department of Plastic and Reconstructive Surgery The Netherlands Cancer Institute–Antoni van Leeuwenhoek Hospital Plesmanlaan 121 NL-1066 CX Amsterdam, The Netherlands [email protected]