Evozierte Potenziale bei Chiari-Malformation Typ I mit Syringomyelie - ein Fallbericht

Abstract

The Chiari-syndrome Type I being a malformation of the posterior cranial fossa often leads to syringomyelia. The disease becomes apparent in adolescence with kyphoscoliosis, headache, vertigo, ataxy, hearing loss, partial paralysis and other neurological disorders. The onset is typically characterized by dissociated anesthesia, due to the frequent localization of the syrinx in the neighborhood of the posterior column of the spinal cord. It is reported a case of an 15-years-old-girl suffering from intensive headache, recurrent left-sided paresthesias and progredient scoliosis. Somatosensory evoked potentials of left ulnar and tibial nerves revealed a complete loss of cortical response. Diagnostic imaging showed an Chiari-malformation I with herniation of cerebellar tonsils and secondary syringomyelia of the cervical spinal cord. After surgical treatment with posterior fossa decompression, C1 laminectomy and partial excision of cerebellar tonsils the patient had a clear improvement in symptoms. Postsurgical the width of cervical syrinx decreases. Now somatosensory evoked potentials of the left ulnar and tibial nerves show amplitude-reduced cortical responses with a normal latency.

The Role of Neurophysiology in Managing Patients with Chiari Malformations

“…When syringomyelia became associated with CM, these authors, in contrast to Jabbari et al [93], observed an increase in the P14-N20 interval; Morioka et al reported similar results [94]. Several case reports and small series with SEP investigations in CM1 patients show abnormal SEPs at a central level, with an absence of cortical responses and an increased latency of cortical potentials or CCT [89,[95][96][97].…”

“…Utzig et al reported the case of a 15-year-old girl complaining of intense headache, recurrent left-sided paresthesia, and progressing scoliosis, who had CM1 with cervical syringomyelia. Ulnar and PTN SEPs showed an absence of cortical responses that improved after surgical treatment with PFD, C1 laminectomy, and partial removal of the cerebellar tonsils with the reappearance of cortical responses of acceptable latency but with reduced amplitude for the left extremities [95].…”

“…Some studies specify the relation between idiopathic scoliosis and CM1, in which abnormal SEPs can be due to tonsillar ectopia or syringomyelia rather than spinal deformity [95,99]. Cheng et al found a relationship between tonsillar ectopia and SEP alterations when studying 164 patients with idiopathic scoliosis, 12 of whom had associated CM1 [99].…”