Single-layer, extramucosal suture technique is preferred as it causes the least tissue necrosis or luminal narrowing The extramucosal suture must include the submucosa because this has a high collagen content and is the most stable suture layer Catgut and silk have been replaced by synthetic, usually absorbable, polymers. The suture materials should be made of absorbable polymer- braided (e.g. polyglactin)/monofilament (e.g. polydioxanone)