Abdominoperineal Resection

Excerpt

Abdominoperineal resection (APR) is predominantly used to treat low-lying rectal carcinoma by removing the sigmoid colon, rectum, and anus, leaving behind a permanent colostomy. The procedure was first described by Sir William Ernest Miles in 1908, developed from earlier operations such as the transcoccygeal Kraske approach, which typically left patients with sphincter dysfunction. Until the late 1930s, the operation was performed as an asynchronous two-stage procedure, consisting of an initial laparotomy to mobilize the sigmoid colon and form an end colostomy, followed by a perineal incision to remove the distal sigmoid and rectum.

Total mesorectal excision (TME) was introduced in the 1980s and was an important advancement in rectal surgery. The TME hypothesis governs that lymph nodes are randomly distributed in the mesorectum and are not easily visible or palpable. Rectal cancers tend to spread extramurally, both in distal and anterior directions, within the surrounding mesorectal lymphovascular tissue (mesorectum). The TME procedure removes the rectum alongside its associated lymph nodes while preserving structures outside the rectal fascia. This technique has reduced local recurrence (12 to 6%) and improved 5-year survival rates (53 to 87%) significantly for upper to mid rectal tumors and is considered the gold standard for rectal cancer resections.

However, for low-lying rectal cancers, conventional APR remains a non-standardized procedure, associated with poorer results than anterior resection, including higher rates of perforation and resection margin involvement. The anatomical planes in conventional APR are not well described and typically involve a less radical perineal dissection. Extralevator abdominoperineal excision (ELAPE) is a relatively new technique that removes the entire pelvic floor by dissecting outside the extralevator muscles, emphasizing precise anatomy and radication resection of the specimen. Most studies indicate that ELAPE decreases the rate of circumferential positive resection margins compared to conventional APR, although extensive resection of the pelvic floor increases the incidence of wound complications and urogenital dysfunction. Due to decreased local recurrence and improved survival, ELAPE is now widely accepted as the preferred approach in low rectal cancers.

In the last 30 years, APR has become increasingly advanced with the introduction of laparoscopic surgery and, more recently, robotics . Laparoscopic APR has several advantages to open surgery, including less blood loss, length of hospital stay, and lower wound infection rates. Robotic-assisted colorectal surgery was first performed in 2002 and had been gaining popularity in rectal surgery. Robotic systems offer many ergonomic advantages over conventional laparoscopy, mainly when working in a deep, narrow operative field represented by the pelvis. Despite studies showing that robotic techniques have faster bowel function recovery and lower conversion rates than laparoscopic surgery, this has ultimately not translated to any superiority in terms of resection margins and oncological outcomes.