During a completion thyroidectomy, the recurrent laryngeal nerve (RLN) is inadvertently transected on the left side. The patient complains of breathlessness at rest 48 hours post-operatively. Flexible laryngoscopy shows bilateral vocal cord paralysis. What is the most likely explanation?

• A Bilateral RLN injury from the index total thyroidectomy
• B Haematoma compressing the trachea
• C External branch of the superior laryngeal nerve bilateral injury
• D Right RLN injury at the initial operation with left RLN injury at completion thyroidectomy ✓

Explanation

In staged thyroidectomy, the right RLN may have been silently injured at the first operation (often undetected if unilateral, causing a soft voice or slight hoarseness), and transection of the left RLN at completion now produces bilateral paralysis. This is the classic trap of proceeding to completion thyroidectomy without pre-operative laryngoscopy to confirm contralateral cord mobility. External branch of the superior laryngeal nerve injury causes loss of high-pitched phonation, not abduction paralysis.

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

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Written and medically reviewed by the StethoPrep medical team.