During anterior resection for rectal cancer, which nerve injury is most likely to cause bladder dysfunction (urinary retention and loss of ejaculation) if the pelvic autonomic nerves are not preserved?

• A Pudendal nerve injury
• B Injury to the superior rectal artery
• C Injury to the inferior hypogastric plexus (pelvic plexus) ✓
• D Obturator nerve injury

Explanation

The inferior hypogastric (pelvic) plexus contains both sympathetic (from hypogastric nerves) and parasympathetic fibers (from pelvic splanchnic nerves, S2-4). Injury during TME causes a mixed defect: loss of sympathetic tone impairs ejaculation and bladder neck closure, while loss of parasympathetic tone causes detrusor acontractility (urinary retention) and erectile dysfunction. Nerve-sparing TME requires meticulous identification of these nerve bundles lateral to the mesorectum at the level of the seminal vesicles.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.