Surgical outcomes using wide suboccipital decompression for adult Chiari I malformation with and without syringomyelia.

Posterior fossa decompression with or without duraplasty is the most common surgical technique employed to treat Chiari-1 malformation (CM). There is considerable debate as to whether large versus small craniectomy leads to better outcomes. The aim of this study was to report our technique and outcomes using a wide suboccipital craniectomy with arachnoid sparing duraplasty. A retrospective review of medical records for symptomatic CM patients with and without syringomyelia was conducted. Follow-up results were obtained via telephone interviews and medical records. Favorable outcome was defined as improvement in self-rated overall status and/or improvement in Glasgow outcome scale (GOS) score. Poor outcome was defined as worsening of either self-rated overall status or GOS score postoperatively. Mean age of 28 female and 2 male patients was 36.6 years (range 20-67). Seven (23%) patients had syringomyelia, one (3%) had hydrocephalus, and two (7%) had prior surgery. Mean follow-up was 27.5 months (range 5-72). Favorable, acceptable, and poor outcomes were achieved in 90%, 3%, and 7% respectively. 87% of respondents indicated they would choose surgery if they had to make a decision again. The most common complication was pseudomeningocele (23%) followed by CSF leak (10%) and meningitis (7%). One transient (3%) neurologic complication occurred. Surgical technique of wide bony decompression of posterior fossa with arachnoid sparing pericranial duraplasty demonstrates favorable outcomes with an acceptable complication rate for patients with symptomatic CM. Prior CM decompression and non-autologous dural graft were associated with poor outcome. Further study is needed to determine the optimal extent of bony decompression.