Perineal-First Approach in Robotic Abdominoperineal Resection

Although abdominoperineal resection (APR) is required for rectal cancer invading the levator ani muscle, its curative outcomes remain poorer than those of other rectal surgeries.^1-3 In particular, the anatomic complexity around the anterior wall of the rectum increases the technical difficulty during APR, resulting in a high frequency of margin involvement that causes local recurrence. In this video, we present the technical details of a robotic perineal-first APR approach.

For a 46 year-old man, locally advanced rectal cancer invading the levator ani muscles was diagnosed. Although total neoadjuvant therapy (8 cycles of induction FOLFOXIRI followed by chemoradiotherapy 50.4 Gy) decreased the tumor size, invasion was suspected still to remain. Therefore, robotic APR was performed. Written informed consent was obtained from the patient. For the perineal-first approach, we created a circular incision around the anus, then divided the fat tissues of the ischiorectal fossa until the levator ani muscle was exposed on both sides. Posterior and anterior dissections were performed along the coccyx and external anal sphincter, respectively. After placement of a lap protector to maintain air-tightness, the robotic approach was initiated. Posterior dissection was performed along the coccyx, then was connected to the already-dissected space created earlier by the perineal approach. Next, the levator ani muscle was divided from the dorsal to the lateral side. Finally, anterior dissection was performed along the prostate, followed by division of the rectourethral muscle, the smooth muscle fibers running vertically. The creation of the already-dissected space on the perineal side offers advantages of robotic manipulation from the abdominal side, especially anterior dissection.

We performed robotic APR using the perineal-first approach for 17 consecutive patients (12 men and 5 women) between 2019 and 2023. All 17 patients achieved complete total mesorectal excision with negative margins. The mean time required for the perineal approach was about 25 min. In anterior dissection using the robotic approach, division of the smooth muscle fibers at the perineal body (i.e., rectourethral muscle in males⁴ or muscular intermingling in females⁵) was reproducibly performed in both males and females.

Robotic APR with a perineal-first approach can be advantageous in ensuring surgical margin safety (especially for the anterior aspect of the rectum).