Facial nerve mapping and monitoring in lymphatic malformation surgery.
OBJECTIVE
Establish the efficacy of preoperative facial nerve mapping and continuous intraoperative EMG monitoring in protecting the facial nerve during resection of cervicofacial lymphatic malformations.


METHODS
Retrospective study in which patients were clinically followed for at least 6 months postoperatively, and long-term outcome was evaluated. Patient demographics, lesion characteristics (i.e., size, stage, location) were recorded. Operative notes revealed surgical techniques, findings, and complications. Preoperative, short-/long-term postoperative facial nerve function was standardized using the House-Brackmann Classification. Mapping was done prior to incision by percutaneously stimulating the facial nerve and its branches and recording the motor responses. Intraoperative monitoring and mapping were accomplished using a four-channel, free-running EMG. Neurophysiologists continuously monitored EMG responses and blindly analyzed intraoperative findings and final EMG interpretations for abnormalities.


RESULTS
Seven patients collectively underwent 8 lymphatic malformation surgeries. Median age was 30 months (2-105 months). Lymphatic malformation diagnosis was recorded in 6/8 surgeries. Facial nerve function was House-Brackmann grade I in 8/8 cases preoperatively. Facial nerve was abnormally elongated in 1/8 cases. EMG monitoring recorded abnormal activity in 4/8 cases--two suggesting facial nerve irritation, and two with possible facial nerve damage. Transient or long-term facial nerve paresis occurred in 1/8 cases (House-Brackmann grade II).


CONCLUSIONS
Preoperative facial nerve mapping combined with continuous intraoperative EMG and mapping is a successful method of identifying the facial nerve course and protecting it from injury during resection of cervicofacial lymphatic malformations involving the facial nerve.
Chiara
Jospeh
J
Division of Otolaryngology - Head and Neck Surgery, Madigan Army Medical Center, Tacoma, WA, USA.
Kinney
Greg
G
Slimp
Jefferson
J
Lee
Gi Soo
GS
Oliaei
Sepehr
S
Perkins
Jonathan A
JA
D002675:Child, Preschool; D015331:Cohort Studies; D004576:Electromyography / Q000379:methods; D005145:Face / Q000294:innervation / Q000601:surgery*; D005154:Facial Nerve / Q000033:anatomy & histology*; D005158:Facial Paralysis / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006776:Hospitals, Pediatric; D006801:Humans; D007223:Infant; D044148:Lymphatic Abnormalities / Q000175:diagnosis / Q000601:surgery*; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods*; D011183:Postoperative Complications / Q000503:physiopathology; D011300:Preoperative Care / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D016896:Treatment Outcome