Change of Anorectal Function after Low Anterior Resection for Rectal Cancer

ABSTRACT

PURPOSE: The anorectal function after a low anterior resection for rectal cancer recovered progressively by 6 12 months after the operation, but the mechanisms and the recovery process are not well understood. The aim of this study was to correlate postoperative anorectal function after low anterior resection with physiologic parameters. METHODS: Sixty-seven patients who underwent a low anterior resection for rectal cancer were studied. The control group was consisted of normal persons. Anorectal physiologic studies were conducted for 6 months postoperatively by using defecographys, anorectal manometry and electomyogram of pudendal nerve. RESULTS: The postoperative anorectal function was gradully improved with time. Defecograms showed that the resting, squeezing, and straining anorectal angles were not significantly increased. Anorectal manometry showed that the threshold volume and the urgency volume were not significantly decreased but the maximal tolerable volume was decreased remarkably. The maximal resting pressure significantly decreased but the maximal squeezing pressure were not. The pudendal nerve electromyograms were not significantly different between the two groups. The patients were divided by based on the anastomosis level. The short anastomosis group showed more impairment in the urgency volume and the maximal resting pressure than that of the long anastomosis group. CONCLUSION: The neorectal volume and the level of anastomosis were important for changes in the anorectal function after a low anterior resecton. Gradual improvement of symptoms resulted from a resected rectal adapted to a neorectal volum.