Sympathetic Inferior Laryngeal Anastomosing Branch: Our Two-Year Experience

Purpose: The knowledge of sympathetic inferior laryngeal anastomosing branch (SILAB) is of great importance as it may mimic the non-recurrent laryngeal nerve (NRLN) leading to recurrent laryngeal nerve (RLN) damage in inexperienced hands. We describe our 2-year experience in SILAB recognition, describing the prevalence, diameter, and method of avoiding SILAB misinterpretation. Methods: Consecutive patients undergoing total thyroidectomy with either prophylactic or therapeutic central compartment lymphadenectomy were included. Operative technique was standardized amongst 2 endocrine surgeons. Data was prospectively collected in a dedicated database. Demographic, pathological, operative, and biochemical parameters were collected, and subgroup outcomes were compared. Results: One hundred thirty-three patients were included in the study, 100 were female (75.2%). Nineteen SILABS were recognized (19/202; 9.4%), 14 (14/99; 14.14%) on the right and 5 (5/103; 4.85%) on the left side. In a total of 6 cases (6/19; 31.5%), the SILAB diameter was similar to the RLN. Conclusion: SILAB may not be as rare as previously thought. It not only branches to the RLN up to 2 cm from the level of the larynx but can branch more caudally up to the level of the clavicle. Intraoperative nerve monitoring is a very useful tool to avoid misinterpretation of SILAB to NRLN when used appropriately.