Abstract: Objective:To study the anatomic characteristics of lateral ligaments of rectum (LLR) by observing the anatomy and surgical videos, and provide the preservingpelvic autonomic nerve anatomical basis and method for total mesorectal excision (TME).
Methods:Five specimens of adult males from Guangdong Pharmaceutical University were dissected and observed. The sharp dissection of rectum was performed by TME, and LLR of 5 specimens was anatomically separated by medial approach. The relationship between LLR and inferior hypogastric plexus was observed, and the distances from midpoint of LLR to sacral promontory and apex of coccyx were measured. The video data of 62 patients with midlow rectal cancer who were admitted to the Third Affiliated Hospital of Sun YatSen University from January 2013 to December 2013 were retrospectively analyzed. There were dense connective bundles at the lateral side of rectum to connect lateral pelvic wall and lateral rectal wall, and LLR and median artery of rectum were searched and confirmed. There were comparisons of anatomic key point and difference of LLR between 5 specimens of adult males and 62 patients with laparoscopic surgery. The measurement data with normal distribution were presented as ±s.
Results:LLR of 5 specimens of adult males was confirmed anatomically and located between the mesorectum and lateral pelvic wall. The nerve fibers originating from inferior hypogastric plexus were found inside LLR. The distance between midpoint of LLR and sacral promontory was (8.2±0.7)cm in the left side and (8.1±0.6)cm in the right side. The distance between midpoint of LLR and apex of coccyx was (5.4±0.8)cm in the left side and (5.0±0.9)cm in the right side. Of 62 patients undergoing laparoscopic surgery, 49 underwent low anterior resection of rectum and 13 underwent abdominoperineal radical resection of rectal cancer. LLR in 62 patients appeared at the level of sacral 3-5. Of 5 specimens of adult males, unilateral middle rectal artery was observed in 3 specimens (2 in the left side and 1 in the right side), and located at the same plane with LLR, with a diameter of (1.1±0.4)mm. The unilateral middle rectal artery was observed in 2 of 62 patients undergoing laparoscopic surgery and located at the same plane together with LLR, with clinical signs of a little blood oozing after ultrasonic scalpel resection.The inferior hypogastric plexus located at the both sides of rectum was detected by anatomy of 5 specimens of adult males along LLR to pelvic walls, which was consistent of postganglionic fibers of sacral sympathetic trunk and parasympathetic preganglionic fibers of sacral ²-4. The inferior hypogastric plexus was squareshaped and reticular structure and located below the peritoneal reflection, at the outside of 1/3 inferior rectum and posterolateral sides of prostate and seminal vesicle. Inferior hypogastric plexus cannot be observed during laparoscopic surgery, while its branch can be observed.
Conclusion:LLR is located at the lateral side of mesorectum, TME and sharp dissection are performed by pursuing closely the outer surface of mesorectum in order to avoid the damage of inferior hypogastric plexuses.