Reduced neorectal capacitance is a more important factor for impaired defecatory function after rectal resection than the anal sphincter pressure

Abstract

The role of the diverse anorectal diagnostic tools like manometry and determination of the preception threshold and the maximal tolerable volume is still a matter of debate. Currently, there is a scarcity of physiological data in the long-term follow-up of patients who underwent sphincter-preserving rectal resection. The aim of this study was therefore to perform these anorectal physiological measurements and to correlate the determined parameters with a faecal incontinence score. In 45 patients, anorectal manometry, electromyography (EMG) and neorectal volume measurements were performed 21.6 +/- 1.4 months after rectal resection. Additionally, patients answered questions to help in the determination of a modified faecal incontinence score. More than half of the patients had more than four bowel movements per day and suffered from defecatory urgency, evacuation and discrimination problems. Manometric data were not related to any functional deficits. In contrast, perception threshold and maximal tolerable volume were correlated with the faecal incontinence score. Defecatory problems especially after radiochemotherapy are still common after rectal resection and the satisfactory functionality post resection should not be oversimplified to just the number of bowel movements. A precondition of an adequate defecation is not only the integrity of the sphincter muscles, but also the recovery of the rectal reservoir function.