Electrophysiological technique for evaluating lesions of the conus medullaris and cauda equina

Restricted access

✓ The authors describe the use of evoked electromyographic responses recorded in the anal sphincter induced by stimulation of the bladder wall and urethra in evaluating lesions of the conus medullaris and cauda equina in 110 patients. This reflex response took effect by way of the pelvic nerves and cauda equina to the sacral cord where the pudendal nerve nucleus was activated, resulting in a contraction of the external anal sphincter. Various lesions along this pathway have been shown to produce either increased latencies and depressed responses or complete loss of response depending on the extent of the lesion. The correlation of results of this technique with clinical, myelographic, and operative findings indicate it to be a useful clinical tool.

Article Information

Address reprint requests to: Gaylan L. Rockswold, M.D., Department of Neurosurgery, Medical School B-590, Mayo Memorial Building, Minneapolis, Minnesota 55455.

© AANS, except where prohibited by US copyright law.

Headings

Figures

  • View in gallery

    Stimulation of urethra with anal sphincter in a normal volunteer. Upper: Normal evoked EMG response. Lower: Complete suppression of the response by voluntary relaxation of the anal sphincter.

  • View in gallery

    Diagram of neural pathways involved in this evoked EMG response technique.

  • View in gallery

    Anal sphincter response to stimulation of urethra. Upper: Control evoked EMG response before Pontocaine. Lower: Absence of evoked EMG response following repeated daily Pontocaine anesthetization of the bladder and urethral mucosa.

  • View in gallery

    Anal sphincter response to stimulation of the bladder. Upper: Control evoked EMG response before spinal block. Center: Absence of evoked EMG response 20 minutes after caudal block. Lower: Return of evoked EMG response 18 hours after caudal block.

  • View in gallery

    An example of a delayed decreased evoked EMG response in a patient with an extensive sacral chordoma. The arrow indicates the beginning of this response.

References

  • 1.

    Barrington FJF: The component reflexes of micturition in the cat. Parts I and II. Brain 54:1771881931Barrington FJF: The component reflexes of micturition in the cat. Parts I and II. Brain 54:177–188 1931

  • 2.

    Bors EComarr AE: Neurological Urology; Physiology of Micturition Its Neurological Disorders and Sequelae. Baltimore: University Park Press1971Bors E Comarr AE: Neurological Urology; Physiology of Micturition Its Neurological Disorders and Sequelae. Baltimore: University Park Press 1971

  • 3.

    Bors ERossier ASullivan J: Urological and neurological observations following anesthetic procedures of patients with spinal cord injuries. II. Cystic and electromyographic effects of topical anesthesias. Urol Survey 12:2052221962Bors E Rossier A Sullivan J: Urological and neurological observations following anesthetic procedures of patients with spinal cord injuries. II. Cystic and electromyographic effects of topical anesthesias. Urol Survey 12:205–222 1962

  • 4.

    Bradley WE: Urethral electromyelography. J Urol 108:5635641972Bradley WE: Urethral electromyelography. J Urol 108:563–564 1972

  • 5.

    Bradley WEScott FBTimm GW: Sphincter electromyography. Urol Clin North Am 1:69801974Bradley WE Scott FB Timm GW: Sphincter electromyography. Urol Clin North Am 1:69–80 1974

  • 6.

    Bradley WETeague CT: Electrophysiology of the pelvic and pudendal nerves in the cat. Exp Neurol 35:3783931972Bradley WE Teague CT: Electrophysiology of the pelvic and pudendal nerves in the cat. Exp Neurol 35:378–393 1972

  • 7.

    Denny-Brown DRobertson EG: On the physiology of micturition. Brain 56:1491911933Denny-Brown D Robertson EG: On the physiology of micturition. Brain 56:149–191 1933

  • 8.

    Garry RCRoberts TDMTodd JK: Reflexes involving the external urethral sphincter in the cat. J Physiol 149:6536651959Garry RC Roberts TDM Todd JK: Reflexes involving the external urethral sphincter in the cat. J Physiol 149:653–665 1959

  • 9.

    Kimura JPowers JMVan Allen MW: Reflex response of orbicularis oculi muscle to supraorbital nerve stimulation. Study in normal subjects and in peripheral facial paresis. Arch Neurol 21:1931991969Kimura J Powers JM Van Allen MW: Reflex response of orbicularis oculi muscle to supraorbital nerve stimulation. Study in normal subjects and in peripheral facial paresis. Arch Neurol 21:193–199 1969

  • 10.

    Kugelberg E: Facial reflexes. Brain 75:3853961952Kugelberg E: Facial reflexes. Brain 75:385–396 1952

  • 11.

    Licht S: History of electrodiagnosis in Licht S (ed): Electrodiagnosis and Electromyography. Baltimore: Waverly Press1971 pp 123Licht S: History of electrodiagnosis in Licht S (ed): Electrodiagnosis and Electromyography. Baltimore: Waverly Press 1971 pp 1–23

  • 12.

    Martin SHBloedel JR: Evaluation of experimental spinal cord injury using cortical evoked potentials. J Neurosurg 39:75811973Martin SH Bloedel JR: Evaluation of experimental spinal cord injury using cortical evoked potentials. J Neurosurg 39:75–81 1973

  • 13.

    Perot PL Jr: The clinical use of somatosensory evoked potentials in spinal cord injury. Clin Neurosurg 20:3673811973Perot PL Jr: The clinical use of somatosensory evoked potentials in spinal cord injury. Clin Neurosurg 20:367–381 1973

TrendMD

Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 30 30 2
Full Text Views 171 171 0
PDF Downloads 123 123 0
EPUB Downloads 0 0 0

PubMed

Google Scholar