Total mesorectal excision for rectal cancer with emphasis on pelvic autonomic nerve preservation: Expert technical tips for robotic surgery.

The primary goal of surgical intervention for rectal cancer is to achieve an oncologic cure while preserving function. Since the introduction of total mesorectal excision (TME), the oncologic outcome has improved greatly in terms of local recurrence and cancer-specific survival. However, there are still concerns regarding functional outcomes such as sexual and urinary dysfunction, even among experienced colorectal surgeons. Intraoperative nerve damage is the primary reason for sexual and urinary dysfunction and occurs due to lack of anatomical knowledge and poor visualization of the pelvic autonomic nerves. The rectum is located concavely along the curved sacrum and both the ischial tuberosity and iliac wing limit the pelvic cavity boundary. Thus, pelvic autonomic nerve preservation during dissection in a narrow or deep pelvis, with adherence to the TME principles, is very challenging for colorectal surgeons. Recent developments in robotic technology enable overcoming these difficulties caused by complex pelvic anatomy. This system can facilitate better preservation of the pelvic autonomic nerve and thereby achieve favorable postoperative sexual and voiding functions after rectal cancer surgery. The nerve-preserving TME technique includes identification and preservation of the superior hypogastric plexus nerve, bilateral hypogastric nerves, pelvic plexus, and neurovascular bundles. Standardized procedures should be performed sequentially as follows: posterior dissection, deep posterior dissection, anterior dissection, posterolateral dissection, and final circumferential pelvic dissection toward the pelvic floor. In future perspective, a structured education program on nerve-preserving robotic TME should be incorporated in the training for minimally invasive surgery.