Comparison of three purse-string suture techniques for prevention of anal leakage during surgery

To compare 3 anal purse-string suture techniques for resistance to leakage and to identify the suture technique requiring the fewest tissue bites to create a consistent leak-proof orifice closure. 18 large-breed canine cadavers. 3 purse-string suture techniques (3 bites with 0.5 cm between bites [technique A], 5 bites with 0.5 cm between bites [technique B], and 3 bites with 1.0 cm between bites [technique C]) were evaluated. Each technique involved 2-0 monofilament nylon suture that was placed in the cutaneous tissue around the anus and knotted with 6 square throws. Standardized 2.0-cm-diameter circular templates with the designated bite number and spacing indicated were used for suture placement. Leak-pressure testing was performed, and the pressure at which saline was first observed leaking from the anus was recorded. The median and interquartile (25th to 75th percentile) range (IQR) were compared among 3 techniques. Median leak pressure for technique A (101 mm Hg; IQR, 35 to 131.3 mm Hg) was significantly greater than that for technique C (19 mm Hg; IQR, 14.3 to 25.3 mm Hg). Median pressure did not differ between techniques A and B (50 mm Hg; IQR, 32.5 to 65 mm Hg) or between techniques B and C. Placement of an anal purse-string suture prevented leakage at physiologic colonic and rectal pressures, regardless of technique. Placement of 3 bites 0.5 cm apart (technique A) is recommended because it used the fewest number of bites and had the highest resistance to leakage.