Anatomical variations of the recurrent laryngeal nerve and postoperative outcomes in thyroid surgeries conducted at a teaching hospital in Ethiopia

Thyroid surgery requires a thorough knowledge of the neck anatomy and its anatomical variations. This is of utmost importance since it is well known that variations of the recurrent laryngeal nerve are prone to iatrogenic injuries. Injury to the recurrent laryngeal nerve is one of the most severe complications of thyroid surgery. Surgeons must comprehensively understand the anatomy of the recurrent laryngeal nerve during thyroid operation. To assess the anatomical variations of recurrent laryngeal nerves, with inferior approach using inferior thyroid artery as a consistent anatomical landmark, and outcomes in patients who had undergone thyroid surgery in Tibebe Ghion Specialised Hospital, Bahir Dar, Ethiopia. An institutional-based prospective observational study of 102 consecutive patients was conducted from June 2021 to August 2022 at Tibebe Ghion Specialized Hospital, Bahir Dar, Ethiopia. Data were collected prospectively using a standardized intraoperative checklist and intraoperative photographs. The study included 102 patients (92 female, 10 male). Age distribution was 18-39 years: 53.9%; 40-60 years: 42.2%; 61-80 years: 3.9%. A total of 156 RLNs were dissected: 87 right and 69 left. Right-side branching was observed in 24.1% of nerves (single trunk 75.9%; bifurcation 18.4%; trifurcation 5.7%); left-side branching occurred in 10.2% (single trunk 89.8%; bifurcation 10.2%). In relation to the ITA, right RLNs were posterior in 68.9%, anterior in 27.7%, and interdigitating among arterial branches in 3.4%; left RLNs were posterior in 91.3%, anterior in 7.3%, and interdigitating in 1.4%. Using the operative landmark of the tracheoesophageal groove (TEG - defined here as the space between the trachea and esophagus at the level of dissection), 93.1% of right RLNs were identified within or adjacent to the TEG and 6.9% were lateral to the tracheal surface; 100% left RLNs were identified within or adjacent to the TEG. Early postoperative course was uneventful in 92.2%; transient hoarseness occurred in 2.0%. Anatomical consideration of the variations in the course, branching pattern, and relation of recurrent laryngeal nerve with inferior thyroid artery and tracheoesophageal groove is essential to minimize complications associated with surgical procedures of the neck, especially thyroidectomy.