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Daniel D. Smeak

Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA

Suture remains the most common means of achieving apposition of wound edges to promote optimal healing (Booth 2003, Smeak 1998). Ideally, sutures should provide support until the repair has regained sufficient strength to withstand tensile forces. When this has been achieved, the suture material should ideally disintegrate in a predictable fashion to prevent further tissue reaction and inhibition of wound healing. Sutures should not create undue tissue reaction because inflammation can prolong the lag phase of wound healing, and delay return to strength. In general, monofilament and synthetic nonabsorbable sutures induce the least amount of tissue reaction, whereas multifilament sutures that are made from natural materials such as silk or chromic catgut are some of the most reactive suture materials. Monofilament absorbable suture materials are often the first choice for surgeons because they are relatively inert and have good to excellent tensile strength, and most have very predictable absorption profiles when exposed to contamination and variable pH environments. Multifilament suture materials have been used successfully in a variety of visceral repairs, however, because most have inherent capillarity (or the drawing up of fluid between the fine woven strands of suture) and high affinity for bacterial adherence, these sutures have fallen out of favor (Chih‐Chang and William 1984). Wicking up of contaminated fluid into multifilament suture filaments from the lumen of hollow organs can contribute to increased tissue reaction, and the bacterial load within the material may be difficult to clear by normal host defenses. For these reasons and others mentioned later, monofilament absorbable sutures are favored and are now used more often in oral and gastrointestinal surgeries.

It should be emphasized that the surgeon's technique (the manner of needle and suture placement, and tissue handling) likely has a greater influence on the generation of tissue inflammation at the repair site than the choice of suture material used in the repair. Needles should be carefully introduced and removed from the tissue “along the curve of the needle” to reduce tissue damage and minimize the size of the needle “track.” Tissue should be well‐apposed with suture without being crushed and handled atraumatically if instruments are required. Forcibly tied sutures and aggressive instrument handling cause tissue damage that impedes healing and inhibits proliferation of new blood vessels, increasing the risk of repair dehiscence (Hoer et al. 2001).

Sutures are classified as absorbable or nonabsorbable, and monofilament or multifilament ( Table 2.1). Absorbable sutures are desirable in gastrointestinal surgery since they eventually are degraded and removed by the body over days to months. Nonabsorbable sutures do not lose significant strength over 60 days, and remain in the tissues to some degree for years. Monofilament sutures are composed of a single smooth strand, whereas multifilament sutures are braided or woven from multiple strands.

Suture is selected for a specific digestive organ wound repair considering the physical characteristics of the suture material (tensile strength and knot security, absorption rate, surface qualities, capillarity, tissue reactivity), and the environment and healing rate of the tissue involved in the repair. As a rule, more pliable and smaller diameter sutures have favorable handling properties in gastrointestinal surgery compared to larger, stiffer suture materials.

Table 2.1 Characteristics of suture materials used in digestive system procedures.

NA = Not Applicable.