Stitching is the commonest method of closing wounds. The edges of the wound need to come together without tension before the skin can be stitched. So on deep wounds, such as major surgery, it is not the visible stitches that are holding you together, but the strong stitches in the layers underneath. The skin is brought together by a row of stitches in the deeper part of the wound first. This allows the skin to be closed without strain. Catgut and nylon are the common threads. Catgut is gradually absorbed and can be used in deeper layers where not too much strength is required. Nylon is difficult to tie, but is strong and leaves little stitch hole scarring. In fact if the "under the skin" technique is used then there are only two stitch holes, one at each end, and no knots are required. A button or pearl is simply attached to each end instead of a knot.
Use of polypropylene suture in arterial anastomosis. The suture material glides easily through the tissues, after all the stitches have been inserted the ends of the artery are brought together by pulling on both ends of the continuous suture.
A variety of suture materials are used in the anastomosis of the intestine. Studies have suggested that anastomoses made with absorbal sutures are weaker than those made with non-absorbable materials during the early phase of healing. In practice two layer anastomoses are made with an inner layer of absorbable sutures and an outer layer of non-absorbable.
