CLINICAL UTILITY OF THE CERNEA CLASSIFICATION DURING THYROIDECTOMY: ANATOMICAL VARIATIONS OF THE EXTERNAL BRANCH OF THE SUPERIOR LARYNGEAL NERVE AND THEIR ASSOCIATION WITH POSTOPERATIVE VOICE CHANGES

Abstract

Background: Injury to the external branch of the superior laryngeal nerve (EBSLN) is a recognized but often underappreciated complication of thyroidectomy that may result in postoperative voice dysfunction. The Cernea classification provides a practical anatomical framework for identifying EBSLN variants that are at increased risk of injury during superior pole dissection. However, evidence correlating the Cernea classification with postoperative voice outcomes remains limited. Methods: A prospective descriptive observational study was conducted among 40 consecutive patients undergoing thyroid surgery in the Department of General Surgery, Sree Balaji Medical College and Hospital, Chennai. The EBSLN was identified intraoperatively whenever feasible and classified according to the Cernea classification. Demographic characteristics, clinical diagnosis, indication for surgery, operative procedure, histopathological findings, and postoperative voice changes were recorded. The association between Cernea classification and postoperative voice changes was evaluated using Fisher's exact test. Results: The mean age of the study population was 40.5 ± 11.4 years, with females comprising 75% of patients. Multinodular goitre was the most common clinical diagnosis (45%), while pressure symptoms were the leading indication for surgery (35%). Total thyroidectomy was performed in 87.5% of patients. The EBSLN was successfully identified in 34 patients (85%). Among the identified nerves, Cernea Type IIa was the most frequent anatomical variant (41.2%), followed by Type I (35.3%) and Type IIb (23.5%). Histopathological examination demonstrated benign thyroid disease in 82.5% of patients. Overall, postoperative voice changes occurred in 15% of patients. No patient with Cernea Type I anatomy developed postoperative voice changes, whereas voice alterations were observed in 14.3% of Type IIa and 50% of Type IIb nerves, demonstrating an increasing frequency of voice dysfunction with anatomically lower nerve courses. Conclusion: Routine intraoperative identification of the EBSLN is feasible during thyroidectomy and facilitates recognition of anatomical variations using the Cernea classification. The higher frequency of postoperative voice changes observed among patients with Cernea Type IIb anatomy highlights the clinical utility of the Cernea classification in identifying high-risk nerve variants during superior pole dissection. Careful anatomical identification and meticulous surgical technique may contribute to improved nerve preservation and better postoperative functional outcomes.