Surgical management of syringomyelia unrelated to Chiari malformation or spinal cord injury

PURPOSE: Syringomyelia is a misleading disease since the problem always lies elsewhere. Arachnoiditis, because it is radiographically difficult to discern, is an especially insidious cause. To better guide selection from among surgical treatment options for syringomyelia, we reviewed our case series of patients without Chiari malformation or spinal injury. METHODS: Excluding syringomyelia due to Chiari malformation, spinal cord injury, and tumors, 32 patients (mean age 44 years) were operated on between 1995 and 2013 and followed up for a mean of 53.8 months. Presumed causes at diagnosis, clinical and radiological findings, type of operation, clinical and radiological outcome were reviewed. RESULTS: Duration of clinical history varied widely (range 6-164 months). Clinical assessment was based on the McCormick classification (15 independent, 17 dependent). Causes included birth trauma, pyogenic meningitis, tuberculous meningitis, postoperative scarring, dysraphism, and basilar impression. Treatment was local decompression with arachnoid lysis and shunts. Hindbrain-related syringomyelia was differentiated from non hindbrain-related syringomyelia. Hindbrain arachnoiditis was significantly associated with radiological findings at the foramen magnum (p = 0.01) and craniocervical decompression (p < 0.03), with good clinical and radiological outcome at 6 months and later follow-up controls (p = 0.02), whereas uneven results were observed in cases of non-hindbrain arachnoiditis. CONCLUSIONS: To remove the cause of syringomyelia, surgical planning will rely on thorough clinical history and accurate imaging to determine the site of cerebrospinal fluid obstruction. Craniocervical decompression to dissect basal arachnoiditis in the posterior fossa can be recommended in hindbrain syringomyelia. Treatment of non-hindbrain arachnoiditis is more controversial, probably owing to uncertainties about the extent of adhesions.