During anterior resection for upper rectal carcinoma, the autonomic nerve supply to the bladder and sexual organs is at risk. Which specific structure, if damaged during dissection along the right pelvic sidewall, most commonly causes retrograde ejaculation in male patients?

• A Right inferior hypogastric plexus (pelvic plexus)
• B Pelvic splanchnic nerves (S2–S4 parasympathetics)
• C Superior hypogastric plexus
• D Right hypogastric nerve ✓

Explanation

Retrograde ejaculation results from failure of bladder neck closure at ejaculation and is mediated by sympathetic nerves. The hypogastric nerves carry sympathetic fibres from the superior hypogastric plexus to the inferior hypogastric plexus; unilateral (especially right) hypogastric nerve injury during high ligation of the inferior mesenteric artery or during lateral rectal dissection leads to retrograde ejaculation. Bilateral damage to the pelvic plexus more severely impairs erection and bladder dysfunction. The superior hypogastric plexus injury affects bilateral sympathetic outflow. Pelvic splanchnic nerves (parasympathetic) are responsible for erection and bladder contraction.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.