Background
We aimed to evaluate the contribution of intraoperative neuromonitoring to the visual
and functional identification of the external branch of the superior laryngeal nerve
and the effect on postoperative voice changes.
Methods
The prospective data of 221 patients (183 women, 38 men) who underwent thyroid operation
with intraoperative neuromonitoring for exploration of the external branch of the
superior laryngeal nerve were evaluated retrospectively. The surface endotracheal
tube–based Medtronic NIM3 (Medtronic, Jacksonville, FL) intraoperative neuromonitoring
device was used. The function of the external branch of the superior laryngeal nerve
was evaluated by cricothyroid muscle twitch. Additionally, the contribution of the
external branch of the superior laryngeal nerve to vocal cord adduction was evaluated
using electromyographic records.
Results
A total of 374 (95.2%) of 393 external branch of the superior laryngeal nerves were
identified; 145 (36.9%) external branch of the superior laryngeal nerves were identified
visually before being stimulated with a probe, and 130 (33.1%) external branch of
the superior laryngeal nerves were identified visually after being identified with
a probe. Although 99 (25.2%) external branch of the superior laryngeal nerves were
identified with a probe, they were not visualized. Intraoperative neuromonitoring
provided meaningful contributions to visual (P = .001) and functional (P = .001) identification of the external branch of the superior laryngeal nerve. Positive
electromyographic responses were recorded from 257 external branch of the superior
laryngeal nerves (68.7%). After the patients with recurrent laryngeal nerve palsy
were excluded, voice changes were detected in 6 (3.3%) of 184 patients with identified
external branch of the superior laryngeal nerves and 3 (20%) of 15 patients in whom
at least 1 external branch of the superior laryngeal nerve could not be identified
with intraoperative neuromonitoring.
Conclusion
Intraoperative neuromonitoring provided an important contribution to the visual and
functional identification of the external branch of the superior laryngeal nerve.
Intraoperative neuromonitoring is a helpful adjunct for identifying the external branch
of the superior laryngeal nerve.
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Article info
Publication history
Published online: December 15, 2016
Accepted:
October 6,
2016
Footnotes
The authors declare that this study has received no financial support. There were no financial or professional associations between the authors and the commercial company that supplied the nerve-monitoring product.
All authors have agreed to the manuscript's content. All authors warrant that the submitted article is original and has not been submitted to another journal for publication, has not been published elsewhere, or if published in whole or in part, all permissions were granted for publication in Surgery.
Identification
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© 2016 Elsevier Inc. All rights reserved.
