High-Precision Identification of Sensory and Motor Branches of the Recurrent Laryngeal Nerve Via Autofluorescence System in Thyroid Surgery

Recurrent laryngeal nerve (RLN) injury is a critical complication in thyroidectomy, with the severe sequelae of operation-related vocal cord palsies. The primary therapy following RLN injury includes voice therapy and surgical reintervention, both of which render subpar results paired with a long road to recovery. Despite the development of technical measures to prevent inadvertent operational injury of the RLN, its occurrence is still a concern. A newly developed handheld device with nerve autofluorescence technology has emerged as a visual aid tool for the intraoperative identification of nervous anatomical landmarks in thyroid surgery, showcasing promising initial findings. This study evaluates the efficacy of the aforementioned device in the intraoperative identification and differentiation of sensory and motor branches of the RLN. Sixteen patients undergoing thyroid surgery were included in this study, of which 16 RLNs and its branches were examined. Basic demographics, indication for thyroid surgery, and postoperative outcomes were identified. Multiple intraoperative images were analyzed through image processing software programs for the total number of nerves and branches, type of branch (e.g., sensory versus motor branches), near-ultraviolet (NUV) light intensity emitted by the nerve structures, and length and angular aperture of branches. The ability to prevent operation-related RLN injury was clinically evaluated at postoperative follow-up. Following analyses, no significant difference was observed between NUV light intensity (p=0.70) or structural length (p=0.18) between sensory and motor nerve branches of the RLN. This was further confirmed by fast Fourier transform (FFT) analyses and three-dimensional surface plots. No partial or total vocal cord palsies were recorded in the perioperative period, thus confirming the accuracy for intraoperative identification of the RLN and the preservation of structural integrity irrespective of surgical technique or type of branch (sensory or motor). Altogether, these findings highlight the potential of autofluorescence technology to enhance surgical precision, improve nerve preservation, and reduce the risk of nerve injury via safe surgical navigation in comparison to current intraoperative neuromonitoring systems limited to motor branch detection.