Electrophysiologic identification and monitoring of the external branch of superior laryngeal nerve during thyroidectomy.
OBJECTIVE
The aim of the study is to examine the correlation between weight, gender, and race with external branch of superior laryngeal nerve (EBSLN) visualization. Furthermore, we compared normative EBSLN neural-monitoring values to those of the recurrent laryngeal nerve (RLN).


METHODS
Retrospective study.


METHODS
North American tertiary academic hospital.


METHODS
A retrospective, institutional review board-approved review was carried out on patients undergoing thyroid surgery by a single surgeon over 3.5 years. Preoperative and postoperative laryngoscopy was done on all patients in accordance with recently published American Academy of Otolaryngology voice optimization at thyroidectomy guidelines, and patients' clinical and operative relevant data were collected.


RESULTS
A total of 447 nerves were at risk in 371 thyroidectomy patients. Of these nerves at risk, 237 (53.02%) were visualized and stimulated. The average amplitude and latency for the EBSLN were significantly lower when compared to the amplitude and the latency of RLN stimulation (P < 0.0001, P < 0.0001, respectively). There was no gender or racial disparity. Out of our study population, the EBSLN was identified in 64.56% in nonobese patients, whereas it was only 40.00% in obese patients (P < 0.001). Additionally, of the 56 patients in whom the EBSLN was visualized on one side and who further underwent bilateral neck exploration, 41 (73%) had visualization of the nerve on the contralateral side as well.


CONCLUSIONS
EBSLN is less likely to be visualized in obese patients; however, there was no gender or racial disparity. Stimulation of EBSLN was felt to be a useful adjunct during superior pole dissection to assure the nerve integrity.


METHODS
4.
Division of Endocrine and Oncologic Surgery, Department of Surgery, Tulane University School of Medicine, New Orleans, Louisiana, U.S.A.
Emad
E
Kandil
Division of Endocrine and Oncologic Surgery, Department of Surgery, Tulane University School of Medicine, New Orleans, Louisiana, U.S.A.
Salah Eldin
SE
Mohamed
Division of Endocrine and Oncologic Surgery, Department of Surgery, Tulane University School of Medicine, New Orleans, Louisiana, U.S.A.
Ahmed
A
Deniwar
Division of Endocrine and Oncologic Surgery, Department of Surgery, Tulane University School of Medicine, New Orleans, Louisiana, U.S.A.
Hossam
H
Mohamed
Division of Endocrine and Oncologic Surgery, Department of Otolaryngology Surgery, Tulane University School of Medicine, New Orleans, Louisiana, U.S.A.
Paul
P
Friedlander
Division of Endocrine and Oncologic Surgery, Department of Otolaryngology Surgery, Tulane University School of Medicine, New Orleans, Louisiana, U.S.A.
Rizwan
R
Aslam
Division of Endocrine and Oncologic Surgery, Department of Surgery, Tulane University School of Medicine, New Orleans, Louisiana, U.S.A.
Ahmad
A
Saeed
Division of Endocrine and Oncologic Surgery, Department of Surgery, Tulane University School of Medicine, New Orleans, Louisiana, U.S.A.
Ibrahim
I
Musa
Massachusetts General Hospital, Division of Surgical Oncology, Endocrine Surgical Service, Harvard Medical School, Cambridge, Massachusetts, U.S.A.
Gregory
G
Randolph
D000368:Aged; D004576:Electromyography / Q000379:methods*; D055724:Electrophysiological Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D012009:Recurrent Laryngeal Nerve / Q000502:physiology*; D012189:Retrospective Studies; D013965:Thyroidectomy; D014826:Vocal Cord Paralysis / Q000175:diagnosis / Q000503:physiopathology / Q000517:prevention & control*
External branch of superior laryngeal nerve; intraoperative nerve monitoring; neural monitoring; recurrent laryngeal nerve; thyroidectomy