VM46 - 4-step Procedure For En Bloc Lateral Pelvic Lymph Node Dissection Using A Transanal Approach

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Purpose/Background: Lateral pelvic lymph node dissection (LLND) is considered necessary for selected patients with rectal cancer with positive lateral node metastasis. However, it is technically challenging and many colorectal surgeons are hesitant to adopt LLND. The technical difficulty of LLND appears to stem from distant and narrow surgical field and complex anatomy. We employ en bloc LLND using a transanal approach for patients with lateral nodal disease after neoadjuvant therapy. This approach seems to improve the feasibility and safety of LLND.

Methods/Interventions: In this video, we show a 4-step procedure for en bloc LLND using a transanal approach. The case was a male after abdominoperineal resection. The left-sided LLND was performed.

Results/Outcomes: 1st step: The lateral pelvic area was entered through the dissection between the S4 pelvic splanchnic nerve and the levator ani muscle. The fatty tissues of the lateral pelvic area were dissected from the uretero-hypogastric nerve fascia.
2nd step: The fatty tissues were dissected from the levator ani and internal obturator muscles. The obturator nerve was identified and preserved. The obturator vessels were divided either by the perineal or transabdominal team.
3rd step: The fatty tissues were isolated from the bottom plane including the coccygeal muscle, internal pudendal artery, and internal iliac vein. Dissection along the bottom plane were performed in a down-to-up manner, and the inferior and superior vesical vessels were divided. The umbilical artery was preserved.
4th step: Finally, the fatty tissues were dissected from the bladder wall and extracted en bloc.

Conclusion/Discussion: In conclusion, en bloc LLND using a transanal approach is simple and reliable.