Gastrointestinal surgery: nerve injury in rectal cancer surgery: practice question

A General Surgery question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Surgery · Gastrointestinal surgery: nerve injury in rectal cancer surgery

Sample item

After anterior resection with high ligation of the inferior mesenteric artery for rectal cancer, a man reports that semen no longer emerges at climax, though he still gets erections. Which structure was most likely injured?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Superior hypogastric plexus

The sympathetic fibres of the superior hypogastric plexus, which lies around the aortic bifurcation and origin of the inferior mesenteric artery, close the bladder neck at ejaculation. Their injury causes retrograde ejaculation, while injury to the pelvic splanchnic nerves mainly causes erectile failure.

Option by option

  • A. Genitofemoral nerve

    The genitofemoral nerve lies on psoas and supplies the cremaster and anterior scrotum.

  • B. Pudendal nerve

    The pudendal nerve is somatic and is not in the dissection field of an anterior resection.

  • C. Superior hypogastric plexus (correct)

    Correct. Sympathetic injury near the inferior mesenteric artery origin causes retrograde ejaculation.

  • D. Pelvic splanchnic nerves

    Pelvic splanchnic (parasympathetic) injury mainly abolishes erection.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this General Surgery question

What is the answer to this General Surgery question?

The best answer is C, Superior hypogastric plexus. The sympathetic fibres of the superior hypogastric plexus, which lies around the aortic bifurcation and origin of the inferior mesenteric artery, close the bladder neck at ejaculation.

Why is "Genitofemoral nerve" not the answer?

The genitofemoral nerve lies on psoas and supplies the cremaster and anterior scrotum.

Why is "Pudendal nerve" not the answer?

The pudendal nerve is somatic and is not in the dissection field of an anterior resection.

Why is "Pelvic splanchnic nerves" not the answer?

Pelvic splanchnic (parasympathetic) injury mainly abolishes erection.

What concept does this question test?

It tests Gastrointestinal surgery: nerve injury in rectal cancer surgery in General Surgery. Their injury causes retrograde ejaculation, while injury to the pelvic splanchnic nerves mainly causes erectile failure.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Gastrointestinal surgery: nerve injury in rectal cancer surgery?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.