Intraoperative Identification and Stimulation of the Ansa Cervicalis Nerve Plexus

Ma C.C.; Mannion K.; Topf M.C.; Rohde S.L.; Langerman A.J.; Netterviell J.L.; Sinard R.; Zealear D.; Li Y.; Schwartz A.R.; Bellotto S.; Wells C.L.; Estes K.E.; Kent D.T. · Otolaryngology - Head and Neck Surgery (United States) (2026) · DOI: 10.1002/ohn.70079

Resumen

Objective: Quantify the anatomic variation of the ansa cervicalis and evaluate neurostimulation of the infrahyoid musculature. Study Design: Intraoperative physiology study. Setting: Tertiary referral center. Methods: Adult patients undergoing lateral neck dissection including level IV for head and neck cancer were recruited. Ansa cervicalis plexus branches were documented during surgical dissection. In a subset of participants, an electrode was placed on branches of the common sternothyroid trunk innervating the sternothyroid and sternohyoid muscles. Hyolaryngeal excursion with neurostimulation was recorded. Results: Measurements were collected from 39 of 50 participants. Reasons for intraoperative exclusion included significant radiation fibrosis (n = 4), nodal disease burden (n = 3), and surgeon preference (n = 4). The mean lengths of the common sternothyroid trunk and sternothyroid branch were 37.6 ± 15.0 mm and 20.4 ± 8.1 mm, respectively. Their respective mean diameters were 2.1 ± 0.7 mm and 1.5 ± 0.5 mm. The distance from sternothyroid branch muscle insertion to the sternum varied substantially (12.8 ± 14.8 mm). Nine patients underwent neurostimulation of the common sternothyroid trunk. The amplitude of first observed muscle contraction was 0.35 ± 0.18 mA and maximal was 0.57 ± 0.40 mA, during which the hyolaryngeal complex descended by 13.6 ± 4.6 mm. In patients with anatomy amenable to neurostimulation of other nerve branches, stimulation of the common sternothyroid trunk produced the greatest hyolaryngeal descent (P <.05). Conclusion: The minor variability observed in ansa cervicalis nerve diameter across patients and branches supports the feasibility of a standardized electrode design for an implantable neurostimulation device. Stimulation of the common sternothyroid trunk resulted in the greatest hyolaryngeal descent, highlighting its value as a potential neuromodulation target.

Instituciones: Universidad Peruana Cayetano Heredia