The differences in clinical, radiological and treatment modalities of cervical intramedullary arachnoid cysts and cervical syringomyelia – report of 12 cases

Anotace: Intramedullary arachnoid cysts are rare cystic masses that are usually mixed up with syringomyelia. It is not necessarily a complication of any pathologic condition in the spine and/or brain but the etiology and management of this entity remains unclear. Syringomyelia is a disorder that is related to an abnormality of the brain and in most cases, occurs as a complication of other pathologies. The aim of this study was to establish the clinical and radiological characteristics of this intramedul­lary arachnoid cyst and discuss the differences between intramedullary arachnoid cyst and the syringomyelia. Patients and methods: A total of 77 patients with intramedullary cystic masses were retrospectively assessed between 2002 and 2012 and 12 of them with intramedullary arachnoid cyst were analysed statistically. All patients had initial scans and fol­lowed up with clinical examinations and MRI images and neuro-electrophysiological tests. Results: The average follow-up duration was 50 months (range 18– 120 months). The mean axial intramedullary arachnoid cyst size was 13.26 ± 4.76mm and the mean sagittal size was 23.29 ± 7.95mm. Neurological examinations were normal in all except one patient who had minor sensory loss due to recent cervical trauma. There were no motor neurological deficits, and all patients remained asymptomatic or stable. The intramedullary arachnoid cyst size and shape remained unchanged radiologically, motor evoked potentials and somatosensory evoked potentials studies revealed normal median and tibial responses initially and at the end of the follow-up in all patients. Conclusion: It is probable that intramedullary arachnoid cyst has different radiologic findings and clinical signs/symptoms from syringomyelia that are associated with different primary causes. And also, the treatment and follow-up modalities are different in intramedullary arachnoid cyst.