Efficacy of multimodality spinal cord monitoring during surgery for neuromuscular scoliosis.
METHODS
This study determined the relative efficacy of somatosensory-evoked potentials and motor-evoked potentials in monitoring spinal cord function during surgery for patients with idiopathic versus neuromuscular scoliosis.


OBJECTIVE
To determine whether patients with idiopathic versus neuromuscular scoliosis demonstrate significantly different somatosensory-evoked potentials and motor-evoked potentials recorded during surgery.


BACKGROUND
Ashkenaze et al (1993) and others have reported that cortical somatosensory-evoked potentials are unreliable when used to monitor spinal cord function in patients with neuromuscular scoliosis. It was recommended that other neurophysiologic tests be used.


METHODS
Somatosensory-evoked potentials and motor-evoked potentials were recorded from two groups of patients: those with idiopathic scoliosis and those with neuromuscular scoliosis. Somatosensory-evoked potentials were obtained before and during surgery. Motor-evoked potentials were obtained during surgery. Normal variability, as indicated from idiopathic scoliotic results, was compared with data obtained from patients with neuromuscular scoliosis. Motor-evoked potentials and somatosensory-evoked potentials were obtained sequentially during the duration of surgery.


RESULTS
Single-channel cortical somatosensory-evoked potentials demonstrated a 27% positive rate, which was consistent with results (28%) from Ashkenaze et al. The use of multiple recording sites for the somatosensory-evoked potentials and the addition of motor-evoked potential procedures indicated that a reliable response could be obtained in more than 96% of the patients. It also was found that cortical somatosensory-evoked potentials were more affected by anesthetic agents when recorded from patients with neuromuscular scoliosis compared with patients with idiopathic scoliosis.


CONCLUSIONS
Single-channel cortical somatosensory-evoked potentials demonstrated a high level of unreliability, which reduced their clinical effectiveness. However, by using multiple recording sites with the somatosensory-evoked potentials and by administering motor-evoked potential procedures, it was possible to monitor spinal cord function in neuromuscular patients and avoid postoperative neurologic deficits.
Owen
J H
JH
Department of Neurology, Johns Hopkins Hospital, Baltimore, Maryland, USA.
Sponseller
P D
PD
Szymanski
J
J
Hurdle
M
M
D000293:Adolescent; D000328:Adult; D000777:Anesthetics / Q000008:administration & dosage; D019054:Evoked Potentials, Motor / Q000187:drug effects; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D006801:Humans; D016343:Monitoring, Intraoperative / Q000379:methods*; D009468:Neuromuscular Diseases / Q000150:complications* / Q000601:surgery; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012600:Scoliosis / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D013116:Spinal Cord / Q000503:physiopathology / Q000601:surgery*
D000777:Anesthetics