Pattern-specific changes and discordant prognostic values of individual leg-muscle motor evoked potentials during spinal surgery.
OBJECTIVE
The aim of the study is to evaluate the efficacy of muscle motor evoked potentials (mMEPs) in individual leg muscles for spinal surgery monitoring.


METHODS
Data were obtained from 209 patients who underwent spine surgery with intra-operative mMEP monitoring in the tibialis anterior (TA) and abductor hallucis (AH) muscles. The mMEP generation, pattern-specific mMEP loss and recovery, and the accuracy of individual mMEP changes in predicting postoperative motor deficit were assessed.


RESULTS
Generation rate of mMEPs was higher in the AH than in the TA (p<0.001). The mMEP in the TA was more sensitive in detecting mMEP loss than in the AH (p<0.001); however, mMEP in the AH was more sensitive in detecting mMEP recovery (p<0.001). The mMEPs in the TA had high sensitivity in predicting sustained postoperative motor deficits. By contrast, mMEPs in the AH showed a high positive predictive value.


CONCLUSIONS
Although mMEPs were generated at a high rate in the AH, mMEP in the TA can play an important complementary role in intra-operative mMEP monitoring, because mMEP in the TA can be more sensitive to potential neural damage.


CONCLUSIONS
Using a combination of muscles with individual sensitivities and clinical significances will improve intra-operative mMEP monitoring strategies.
Department of Neurology, Seoul National University, College of Medicine, Seoul, Republic of Korea.
Sung-Min
SM
Kim
Hyeran
H
Yang
Soon-Bu
SB
Park
Suk Geun
SG
Han
Kun-Woo
KW
Park
Sang Hoon
SH
Yoon
Seung-Jae
SJ
Hyun
Hyun-Jib
HJ
Kim
Kyung Seok
KS
Park
Kwang-Woo
KW
Lee
D000328:Adult; D000368:Aged; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D007866:Leg / Q000294:innervation* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D008991:Monitoring, Physiologic / Q000379:methods; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation* / Q000503:physiopathology; D009422:Nervous System Diseases / Q000175:diagnosis / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D013131:Spine / Q000601:surgery*