Identification of the surgical indication line for the Denonvilliers’ fascia and its anatomy in patients with rectal cancer

BACKGROUND: The high rate of urogenital dysfunction after traditional total mesorectal excision (TME) has caused doubts among scholars on the standard fashion of dissection. We have proposed the necessity to preserve the Denonvilliers' fascia in patients with rectal cancer. However, how to accurately locate the Denonvilliers' fascia is unclear. This study aimed to explore anatomical features of the Denonvilliers' fascia by comparing autopsy findings and observations of surgical videos so as to propose a dissection method for the preservation of pelvic autonomic nerves during rectal cancer surgery. METHODS: Five adult male cadaver specimens were dissected, and surgical videos of 135 patients who underwent TME for mid-low rectal cancer between January 2009 and February 2019 were reviewed to identify and compare the structure of the Denonvilliers' fascia. RESULTS: The monolayer structure of the Denonvilliers' fascia was observed in 5 male cadaver specimens, and it was located between the rectum, the bottom of the bladder, the seminal vesicles, the vas deferens, and the prostate. The Denonvilliers' fascia was originated from the rectovesical pouch (or rectum-uterus pouch), down to fuse caudally with the rectourethral muscle at the apex of the prostate, and fused to the lateral ligaments on both sides. The fascia was thinner on the midline with a thickness of 1.06 +/- 0.10 mm. The crown shape of the Denonvilliers' fascia was slightly triangular, with a height of approximately 5.42 +/- 0.16 cm at midline. Nerves were more densely distributed in front of the Denonvilliers' fascia than behind, especially on both sides of it. Under laparoscopic view, the Denonvilliers' fascia was originated at the lowest point of the rectovesical pouch (or rectum-uterus pouch), with a thickened white line which was a good mark for identifying the Denonvilliers' fascia. CONCLUSION: Identification of the surgical indication line for the Denonvilliers' fascia could help us identify the Denonvilliers' fascia, and it would improve our ability to protect the pelvic autonomic function of patients undergoing TME for rectal cancer.