Intraoperative Identification and Preservation of a True Double Left Recurrent Laryngeal Nerve During Total Thyroidectomy for Benign Multinodular Goitre: A Case Report.

Abstract

Background:
Recurrent laryngeal nerve (RLN) injury remains one of the most feared complications of thyroid and parathyroid surgery because during these surgeries dissection is performed in a confined anatomical field adjacent to vital structures. Although temporary vocal fold palsy and permanent RLN injury are well recognized after thyroidectomy, the risk is amplified by anatomical variations of the RLN. While extra-laryngeal branching is relatively common true RLN duplication is exceptionally rare and may be overlooked unless the nerve is routinely visualized and traced to its laryngeal entry near the ligament of Berry.
Case report:
A69-year-old man presented with a 10-year history of progressively enlarging anterior neck swelling, with rapid enlargement and bilateral extension during the month prior to admission. Imaging demonstrated tracheal deviation and narrowing at the C7–T2 level. Neck MRI revealed a large right thyroid mass with central degenerative areas and suspected mediastinal extension; fine-needle aspiration cytology showed benign findings (Bethesda II). The patient was diagnosed with bilateral suspected non-toxic thyroid nodules with compressive effect and underwent total thyroidectomy. Intraoperatively, two distinct RLN structures (double RLN) were identified on the left side ascending in close proximity toward the laryngeal entry point. Both components were meticulously dissected in the capsular plane, traced through the critical region near Berry's ligament, and preserved without traction or thermal injury. Postoperatively, there was no hoarseness, respiratory compromise, or clinical hypocalcemia.
Conclusion:
This case highlights an extremely rare anatomical variant—true duplication of the left RLN—encountered during thyroidectomy for benign multinodular goitre. Systematic RLN visualization and careful tracing to the laryngeal inlet, especially around Berry's ligament, are essential to prevent nerve injury and postoperative vocal cord dysfunction.