Computer-assisted evoked electromyography with stimulating surgical instruments for recurrent/external laryngeal nerve identification and preservation in thyroid and parathyroid operation.
BACKGROUND
The reported incidence of recurrent laryngeal nerve (RLN) palsy/paralysis in thyroid and parathyroid operation ranges from 2% to 13%. Injury to the external branch of the superior laryngeal nerve (EBSLN) is less clearly documented. We hypothesized that a novel evoked electromyography system using an audio warning alarm might be beneficial for detection and preservation of the RLN and EBSLN.


METHODS
A total of 117 thyroid/parathyroid operations were performed using a nerve locator/monitor (Neurovision SE, RLN Systems Inc, Jefferson City, Mo). Dissection was performed using a stimulating hemostat with conduction to an endotracheal surface electrode.


RESULTS
A total of 97 thyroidectomies (50 total, 47 lobectomies) and 20 parathyroidectomies (16 directed, 4 bilateral) were performed representing 176 RLN and 152 EBSLN at risk. Of 176 RLN, 161 were correctly identified by the nerve stimulator alarm including 2 nonrecurrent nerves. The cricothyroid space and the superior pole vessels were scanned to identify the EBSLN by observing for cricothyroideus contraction or an alarm. Fourteen of 152 (8.9%) cases of type 2 anatomy were suggested where meticulous dissection of superior pole vessels prevented EBSLN injury.


CONCLUSIONS
Computer-assisted evoked electromyography with stimulating surgical instruments is a useful surgical tool. This technology may be especially useful in reoperation in dense scar tissue and preserving the EBSLN in thyroid operation.
Dackiw
Alan P B
AP
University of Toronto, Princess Margaret Hospital, 610 University Avenue, Suite 3-130, Toronto, Ontario, Canada, M5G 2M9.
Rotstein
Lorne E
LE
Clark
Orlo H
OH
D003936:Diagnosis, Computer-Assisted; D004576:Electromyography / Q000295:instrumentation / Q000379:methods*; D005071:Evoked Potentials; D006801:Humans; D007442:Intubation, Intratracheal; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D010279:Parathyroid Diseases / Q000601:surgery*; D016105:Parathyroidectomy; D012009:Recurrent Laryngeal Nerve / Q000502:physiology* / Q000601:surgery; D013959:Thyroid Diseases / Q000601:surgery*; D013965:Thyroidectomy