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. 2025 Mar 8;17(3):e80262.
doi: 10.7759/cureus.80262. eCollection 2025 Mar.

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

Fernando Dip  1 , Rene Aleman  2   1 , Federico Marinelli  1 , Javier Guiselli  1 , Raul Rosenthal  2   1 , Alberto Rancati  1 , Diego Sinagra  1
Affiliations

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

Fernando Dip et al. Cureus. .

Abstract

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.

Keywords: autofluorescence; navigational surgery; optical imaging; surgical enhancement; thyroidectomy.

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Conflict of interest statement

Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: Fernando Dip, Rene Aleman, Raul J. Rosenthal, and Alberto Rancati. declare(s) non-financial support from Dendrite® Imaging Inc. Investment and development. . Fernando Dip, Rene Aleman, Raul J. Rosenthal, Alaberto Rancati. declare(s) non-financial support from Intelligent Surgical Eye®. Investment and development. . Intellectual property info: The nerve autofluorescence optic imaging technology in the Dendrite® device is proprietary to Dendrite® Imaging Inc (Gera, Germany). All images are property of the authors associated to the aforementioned company. The present manuscript has resulted in no compensation to the authors and/or disclosed companies. Other relationships: Dr. Dip, Dr. Rosenthal, Dr. Rancati, and Dr. Aleman are active developing and investing members for Dendrite® Imaging Inc (Gera, Germany).

Figures

Figure 1
Figure 1. Approach
Top left: conventional white light view during thyroidectomy. Top right: exteriorization of the thyroid gland visualized by the Dendrite® device and identification of the recurrent laryngeal nerve. Bottom: stepwise approach methodology. From left to right: incision and exposure of the thyroid gland followed by Dendrite® device identification of RLN with concomitant IONM of motor branches and subsequent image processing using ImageJ and MIPAV software programs. RLN, recurrent laryngeal nerve
Figure 2
Figure 2. Structural length comparison
Comparative figure of the mean structural length for group A (sensory branches) versus group B (motor branches).
Figure 3
Figure 3. NUV light intensity comparison
Comparative figure of the mean NUV light intensity for group A (sensory branches) versus group B (motor branches). NUV, near-ultraviolet
Figure 4
Figure 4. NUV light intensity distribution and 3D plots
Top: 3D plot for the dimensional NUV light intensity distribution of a motor branch. Bottom: 3D plot for the dimensional NUV light intensity distribution of a sensory branch. NUV, near-ultraviolet
See this image and copyright information in PMC

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