Determination of the peritoneal reflection using intraoperative proctoscopy

PURPOSE: Rectal carcinomas are amenable to transanal excision in 3 to 5 percent of cases. Location below the peritoneal reflection is one requirement for transanal excision and transanal endoscopic microsurgery. The location of the peritoneal reflection has not been extensively studied in living patients. METHODS: This study investigated the location of the peritoneal reflection in 50 patients undergoing laparotomy. The distance from the anal verge to the peritoneal reflection was measured in each patient via simultaneous intraoperative proctoscopy and intra-abdominal visualization of the peritoneal reflection. The mean distance to the peritoneal reflection, range of measurements, and complications of proctoscopy were recorded. RESULTS: Intraoperative proctoscopy was performed on 50 patients after informed consent. The mean lengths of the peritoneal reflection were 9 cm anteriorly, 12.2 cm laterally, and 14.8 cm posteriorly for females, and 9.7 cm anteriorly, 12.8 cm laterally, and 15.5 cm posteriorly for males. The lengths of the anterior, lateral, and posterior peritoneal measurements were statistically different from one another, regardless of gender (P < 0.01). There were no complications of proctoscopy. CONCLUSIONS: Our data indicated that the peritoneal reflection is located higher on the rectum than reported in autopsy studies, and that there is no difference between males and females. Knowledge of the location and position of a rectal carcinoma in relationship to the peritoneal reflection will help the surgeon optimize the use of transanal techniques of resection.