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3 Suture Patterns for Gastrointestinal Surgery
Daniel D. Smeak
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
3.1 One‐ or Two‐Layer Closure
Although this is still a controversial topic, both techniques have potential downfalls that could endanger an anastomosis. One would think two‐layer closures are better than one‐layer since they might provide added strength initially. However, they increase the inflammatory response in the early stages of visceral healing owing to the extra tissue handling, suture material, and ischemia of the inverted tissue cuff (Orr 1969; McAdams et al. 1970; Goligher et al. 1977). Excess inflammation at the healing site results in a weaker anastomosis as more collagen is broken down during the inflammatory and debridement phases of healing. Advocates of single‐layer closures argue that this technique results in a larger lumen with less damage to the tissue edges (Thornton and Barbul 1997). Currently, in most conditions, a single‐layer closure for most gastrointestinal repairs is considered adequate (Sajid et al. 2012). Provided the lumen is not compromised, double‐layer repairs are sometimes elected when the surgeon expects higher intraluminal pressures, or when the tissue edge is considered extra friable or when sutures in the first layer tend to cut through the tissue.
3.2 Tissue Inversion, Eversion, or Apposition
Inverting suture patterns cause greater initial narrowing of the intestinal lumen (Bellenger 1982) but their main advantage is that these patterns provide more consistent initial leak‐proof closures (higher leak pressures). Everting patterns elicit greater adhesion formation to exposed mucosal edges, and provide the least leak‐proof closures, and therefore they are not currently recommended for gastrointestinal closure (Hamilton 1967). In theory, approximating (appositional) patterns accurately align tissue layers compared to inverting and everting patterns, and therefore, these patterns are now preferred for gastrointestinal closures. However, in practice, consistent tissue apposition with approximating suture patterns infrequently occurs when anastomoses were evaluated histologically. Nevertheless, direct apposition of all intestinal layers, particularly the submucosal layer, has been found to result in the most rapid direct bridging of the repair (Jansen et al. 1981).
3.3 Stapled or Hand‐Sutured Anastomosis
Stapled anastomoses are technically easier and faster but they do not replace adherence to the principles of good surgical technique for successful intestinal healing (Chassin et al. 1984). Regardless of technique, an adequate blood supply and absence of contamination or tension is paramount to successful repair. Linear staples in thicker visceral tissue may not purchase the strength holding layer on both sides of the staple line leading to a weakened repair (Snowden et al. 2016). It is critical that the correct staple leg length is chosen when visceral edges are edematous or inflamed. In most situations, linear staple cartridges with 3.5 mm staples are acceptable for most intestinal repairs in dogs and cats. Linear staples with 4.8 mm staples are chosen for thicker intestinal edges and for stomach repairs. Stapled anastomoses were not at more risk for dehiscence when performed in the face of septic peritonitis, unlike what has been encountered in hand‐sewn repairs in multiple retrospective studies (Snowden et al., 2016; Davis et al. 2018).
3.4 Appositional Suture Patterns
3.4.1 Simple Interrupted
The major advantage of simple interrupted suture patterns is the ability to precisely control tension at each stitch along the wound with variable spreading forces along the margins (Moy et al. 1992). Another advantage is that each interrupted stitch is a separate entity, and failure of the single suture or knot may be inconsequential. Interrupted suture patterns take longer to place and knot, the individual knots increase the volume of foreign material in repairs, and suture economy suffers. A retrospective study comparing simple interrupted and continuous appositional patterns for enterotomy and anastomosis in dogs and cats found a low and comparable rate of enteric leakage with either pattern (Weisman et al. 1999).
3.4.2 Simple Continuous
The major advantage of simple continuous patterns is the speed of placement, and they generally create a more leak‐proof closure when compared to their interrupted counterparts. Continuous lines use less suture and minimize exposure of knots that can untie or cause tissue reaction. Surgeons have less precise control of suture tension and wound approximation throughout the repair. Insecure knots, lack of adequate needle purchase of the strength holding layer, or suture breakage can have disastrous effects on gastrointestinal
