Neurophysiologic investigation of anal function following double stapling anastomosis

Manual dilatation of the anal sphincter and transanal introduction of the circular stapling device are required for intraluminal stapling anastomosis. This procedure has been regarded as one of the causes of postoperative evacuatory disorder in low anterior resection. However, there has been no evidence of this matter. Therefore, we conducted this study to clarify the impact of the procedure of stapling anastomosis on postoperative anal function.

Twenty-five cases with sigmoid colon cancer underwent potentially curative sigmoid colectomy with stapling anastomosis (ST group) and 20 cases with hand-sewn anastomosis (non-ST group). The patients were questioned regarding the daily frequency of bowel movement, the presence of urgency and soiling, and Wexner's incontinence score. Anorectal manomatry and pudendal nerve terminal motor latency were also evaluated. The patients' questionnaire and physiologic examinations were prospectively obtained before, and 1 and 6 months after the operation.

Postoperative bowel habit was graded as satisfied in 92% (23/25 patients) in the ST group and 90% (18/20 patients) in the non-ST group. There was no significant difference between the 2 groups in terms of presence of fecal incontinence, discrimination of gas and stool, and daily frequency of bowel movement. In anal manometry, there was no significant difference between the 2 groups regarding the resting and squeezing anal canal sphincter pressures at 1 and 6 months postoperatively. Pudendal nerve terminal motor latency showed their latency from 2.0 to 2.5 ms throughout the periods, and there was no difference between the 2 groups before, and 1 and 6 months after the operation.

Stapling anastomosis does not affect anal function in the early postoperative period.