Mechanically elicited nerve root discharge: mechanical irritation and waveform.
OBJECTIVE
Intraoperative monitoring is very important for protecting nerve roots during lumbar surgery for spinal degeneration. Our objective was to evaluate the correlation between the type of mechanical irritation and waveform by mechanically elicited EMGs during the surgery.


METHODS
Mechanically elicited EMGs were recorded bilaterally on muscle groups innervated by the lumbar nerve roots in the area of surgery in 24 consecutive patients with lumbar spinal degenerative disease.


RESULTS
It was confirmed that surgical irritation produced 3 types of waveforms as discharges from nerve roots; short, waning and continuous discharges. Each waveform was easily elicited mechanically and was sensitively related to the type and strength of mechanical stimulation.


CONCLUSIONS
It was indicated that the mechanical irritation on the root could elicit the nerve root discharge with no post-operative nerve root deficit. It may be useful to monitor the mechanically elicited EMGs during the surgery for spinal degeneration.
Obi
T
T
Department of Neurology, National Shizuoka Hospital, Japan.
Mochizuki
M
M
Isobe
K
K
Mizoguchi
K
K
Takatsu
M
M
Nishimura
Y
Y
D000328:Adult; D000368:Aged; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D007796:Laminectomy; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D018482:Muscle, Skeletal / Q000294:innervation; D010812:Physical Stimulation; D013122:Spinal Diseases / Q000601:surgery*; D013123:Spinal Fusion; D013126:Spinal Nerve Roots / Q000502:physiology*