Introduction: transanal endoscopic microsurgery (TEM) was developed in 1983 by Büess as a minimally invasive technique to manage rectal villous adenomas and early rectal adenocarcinomas. Many studies have been published worldwide about its excellent results in morbidity and recidive rate, but there are few studies addressing functional results. The objective of this study is to analyze the effect of this technique in the anal anatomy and compare with the manometric results.
Material and methods: we devised a prospective study of 40 patients. 39% female, 61% male. All of them filled an incontinence questionnaire (Pescatori scale) and endoanal ultrasonography and manometry was carried out preoperatively, third month postoperative and at sixth month only if incontinence appeared.
Results: 32 patients (80%) had villous adenomas and 8 patients (20%) had adenocarcinomas (uT1). Three patients complained of flatus incontinence at 3rd postoperative month that disappeared with normal continence at 6th month. Anorectal manometric values: mean anal resting pressure (ARP) decreased at 3rd month (from 87.2 mmHg to 70.1 mmHg), as it was for maximal squeeze pressure (MSP) from 152.5 mmHg preoperatively to 142.2 mmHg at 3rd month. Ultrasonography demonstrated internal anal sphincter (IAS) rupture in 3 patients, with a full integrity of the external anal sphincter in all patients.
Conclusions: during TEM, a significant anal dilatation occurs, because of rectoscopy (40 mm wide), what can produce a rupture of IAS, with the consequent decreasing in ARP, and a dilatation without rupture of external sphincter what produces a decreasing of MSP. The fall of anal pressures had minima clinical repercussion when sphincter is intact, but when IAS is broken a temporal incontinence develops.