Anorectal functional results after transanal endoscopic microsurgery in benign and early malignant tumors.

BACKGROUND: Transanal endoscopic microsurgery (TEM) has been suggested as a minimally invasive procedure of low morbidity for rectal villous adenomas and early anorectal adenocarcinomas. It has been used clinically in many areas outside of China for more than 20 years, but it began in mainland China only about 2 years ago. Some articles have reported excellent results with regard to morbidity and relapse rate with TEM, but there are no studies addressing its functional results in China until now. The aim of the present study was to analyze the effect of TEM on the manometric results.
METHODS: Thirty-seven patients (16 females, 21 males) underwent TEM and were followed for more than 6 months. Anorectal manometry and an incontinence questionnaire were administered 1 week preoperatively, 2 weeks postoperatively, 3 and 6 months postoperatively.
RESULTS: Of the 37 patients, 24 had villous adenomas and 13 had adenocarcinomas (11 uT1 and 2 uT2). Anorectal manometric values showed the mean anal resting pressure (ARP) decrease from 45 +/- 6 mmHg to 29 +/- 4 mmHg (p < 0.05) and the maximum tolerable volume (MTV) decrease from 175 +/- 21 ml to 90 +/- 15 ml (p < 0.05) at the third month after TEM. Maximal squeeze pressure (MSP) decreased from 181 +/- 20 mmHg to 92 +/- 14 mmHg (p < 0.05) at second week after operation and returned to normal value by the third postoperative month. The ARP and MTV were 45 +/- 5 mmHg and 177 +/- 21 ml, respectively, at 6 months after TEM, near the normal value (p > 0.05). Rectoanal inhibitory reflex (RAIR) was absent preoperatively in two patients; it was also absent in 10 patients 3 months postoperatively and in three patients 6 months postoperatively. Endosonography demonstrated internal anal sphincter (IAS) rupture in five patients, and full integrity of the external anal sphincter (EAS) in all patients. Of the five patients with IAS rupture, four had temporary incontinence to flatus normalized up to three postoperative months. Most patients had more times of stools per day and relative higher Wexner scores in a short period after TEM. All these patients were followed for 6-20 months with no incidence of relapse.
CONCLUSIONS: Anorectal function was preserved well after TEM, although some anorectal manometric parameters changed over time. Thus TEM is safe, in terms of anorectal function, for the cure of benign and early malignant tumors of the rectum.