Medical College of Wisconsin
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Lack of specificity in electrophysiological identification of lower sacral roots during selective dorsal rhizotomy. J Neurosurg 1997 Jan;86(1):28-33 PMID: 8988078

Pubmed ID



The authors investigated the efficacy of anal sphincter electromyography (EMG) in identifying the lower sacral roots during selective dorsal rhizotomy. In nine children undergoing selective dorsal rhizotomy for cerebral palsy (CP) spasticity, direct electrical stimulation of the L1-S5 dorsal and ventral roots was performed while monitoring EMG responses from the anal sphincter and lower-extremity muscles. Anal sphincter activation was seen with stimulation of lumbosacral roots at many levels. Stimulation of dorsal and ventral roots gave anal sphincter EMG responses in 100% of the dorsal and ventral roots from L-4 and caudally. Only at the L-1 level did a minority of nerve roots have anal sphincter response to stimulation. Patterns of extremity muscle and sphincter activation specific to the S3-5 roots, namely anal sphincter activation without activation of other muscle groups, were found in only five (22%) of 23 roots stimulated. The pattern of stimulation responses in the majority of S3-5 roots indicated that the pathophysiology of lower-extremity spasticity in CP may involve the anal sphincter and does not spare the lower sacral roots. Thus, this study indicates that electrophysiological mapping alone, without anatomical identification, cannot be used to identify the lower sacral roots during selective dorsal rhizotomy for CP spasticity, and it proposes a model for investigation of associated bowel and bladder symptoms.

Author List

Ojemann JG, Park TS, Komanetsky R, Day RA, Kaufman BA


Bruce A. Kaufman MD Professor in the Neurosurgery department at Medical College of Wisconsin


2-s2.0-0031022949   10 Citations

MESH terms used to index this publication - Major topics in bold

Anal Canal
Cerebral Palsy
Child, Preschool
Electric Stimulation
Fecal Incontinence
Follow-Up Studies
Intraoperative Complications
Monitoring, Intraoperative
Monitoring, Physiologic
Muscle Contraction
Muscle Spasticity
Sensitivity and Specificity
Spinal Nerve Roots
jenkins-FCD Prod-336 69ef4a6b262d135130251597d5d39873903802b5