Vocal cord paralysis predicted by neural monitoring electrophysiologic changes with recurrent laryngeal nerve compressive neuropraxic injury in a canine model.
Recurrent laryngeal nerve (RLN) injury is a known complication of thyroid/parathyroid surgery. Intraoperative nerve monitoring (IONM) has been used to gain more information regarding the functional status of the RLN intraoperatively; however, the electromyography (EMG) parameters of RLN after nontransection neuropraxic compressive injury remain unknown.



We developed a canine model to identify IONM EMG correlates of postoperative vocal cord paralysis (VCP) using a standardized method to simulate surgical RLN compression sufficient to cause VCP.



Compression nerve injury decreased EMG amplitude and increased EMG latency, with a 60% increase in RLN threshold stimulation compared to preinjury values. If RLN amplitude decreases by 80% with an absolute amplitude of 300 μV or less in combination with a latency increase of 10% or more, then nerve injury and associated VCP is likely.



These results may help surgeons to prognosticate postoperative neural function and intraoperative decision-making regarding contralateral thyroid surgery. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1341-E1350, 2016.
Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts.
Sidharth V
SV
Puram
Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts.
Harold
H
Chow
Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts.|Department of Otorhinolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Che-Wei
CW
Wu
Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
James T
JT
Heaton
Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts.
Dipti
D
Kamani
Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts.
Gautham
G
Gorti
Department of Otorhinolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Feng Yu
FY
Chiang
Department of Surgical Sciences and Human Morphology, Division of Surgery, University of Insubria - School of Medicine, Varese, Italy.
Gianlorenzo
G
Dionigi
Department of Endocrine Surgery, Jagiellonian University Medical College, Krakow, Poland.
Marcin
M
Barczyński
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Rick
R
Schneider
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Henning
H
Dralle
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Kerstin
K
Lorenz
Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts.|Division of Surgical Oncology, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
Gregory W
GW
Randolph
D000818:Animals; D004285:Dogs; D004576:Electromyography; D005260:Female; D064795:Intraoperative Neurophysiological Monitoring; D008297:Male; D061226:Recurrent Laryngeal Nerve Injuries / Q000473:pathology*; D013965:Thyroidectomy; D014826:Vocal Cord Paralysis / Q000175:diagnosis* / Q000473:pathology
endocrine; injury; intraoperative nerve monitoring (IONM); recurrent laryngeal nerve; thyroid surgery; vocal cord palsy