Denonvilliers' fascia lies anterior to the fascia propria and rectal dissection plane in total mesorectal excision

PURPOSE: Opinion is divided whether Denonvilliers' fascialies anterior or posterior to the anatomic fascia propria plane of anterior rectal dissection in total mesorectal excision. This study was designed to evaluate this anatomic relationship by assessing the presence or absence of Denonvilliers' fascia on the anterior surface of the extraperitoneal rectum in specimens resected for both nonanterior and anterior rectal cancer in males. METHODS: Surgical specimens were collected prospectively from males undergoing total mesorectal excision for mid and low rectal cancer, with a deep dissection of the anterior extraperitoneal rectum to the pelvic floor. Specimens were histopathologically analyzed using best practice methods for rectal cancer. The anterior aspects of the extraperitoneal rectal sections were examined microscopically for the presence or absence of Denonvilliers' fascia. RESULTS: Thirty rectal specimens were examined. Denonvilliers' fascia was present in 12 (40 percent) and absent in 18 specimens (60 percent). Denonvilliers' fascia was significantly more frequently present when tumor involved (55 percent) rather than spared the anterior rectal quadrant (10 percent; difference between groups 45 percent; 95 percent confidence interval, 30-60 percent; P = 0.024, Fisher's exact test). CONCLUSIONS: When tumors were nonanterior, rectal dissection was conducted on fascia propria in the usual anatomic plane, and Denonviltiers' fascia was not present on the specimen. It was almost exclusively found in anterior tumors, deliberately taken by a radical extra-anatomic anterior dissection in the extramesorectal dissection plane. Denonvilliers' fascia lies anterior to the anatomic fascia propria plane of anterior rectal dissection and is more closely applied to the prostate than the rectum.