[Evoked motor and sensory potentials in syringomyelia].

Seventy nine patients were admitted for syringomyelia. Fifty-nine had a malformative syringomyelia, 15 a post-traumatic syrinx and 5 a syringomyelia related to a meningitis. For all the patients, the diagnosis of syringomyelia was performed by MRI with measures of syrinx extension and transverse diameter. Posterior tibial somato sensory evoked potentials (PT SEP), median (M SEP), trigeminal (V3 SEP), brain stem auditory evoked potentials (BEAP), cortical and cervical motor evoked potentials (MEP) were correlated with clinical and radiological findings. SEP abnormalities were not correlated with the duration of symptoms. PT SEP proved to be more sensitive than M SEP, MEP abnormalities were very frequent (72% of the cases), even without clinical motor deficit. Trigeminal SEP were more sensitive than BAEP which were not related to the presence of associated cranio vertebral abnormalities. No significant relationship between clinical and radiological results was observed. There was a positive relationship between electrophysiological and radiological results. Nevertheless, a good correlation was observed between lateral clinical, MRI and electrophysiological results. Abnormal trigeminal SEP were detected in 46.6% of the patients with high cervical syringomyelia. In all cases, trigeminal SEP and MEP should be done in association with M and PT SEP as both of them detect subclinical evidence of spinal cord dysfunction in syringomyelia.