High long-term symptomatic recurrence rates after Chiari-1 decompression without dural opening: A single center experience

ObjectiveWe evaluated long-term outcomes of posterior fossa decompression (PFD) without duroplasty in consecutive patients with newly diagnosed Chiari-1 malformation.MethodsWe searched the institutional database for all adult patients who underwent Chiari decompression between 1995 and 2007. PFD was offered to all consecutive patients with Chairi-1 malformation during this time period. We excluded patients who underwent re-exploration after initial Chiari-1 decompression elsewhere. Besides the demographic variables, presenting symptoms, neurological and radiographic findings the clinical records were studied for long-term outcomes specifically symptomatic improvement. We defined symptomatic improvement as resolution of all presenting symptoms including pain and/or neurological deficits at the last follow-up. The factors associated with symptom recurrence were also analyzed.ResultsWe identified 47 patients who underwent PFD for Chiari-1 malformation. Syringomyelia was noted in 36.2% of patients and the mean tonsilar herniation was 12.6 mm. At a mean follow-up of 9.3 years, the symptomatic improvement rate was 60.6%. There were no operative complications. Repeat posterior fossa decompression was required for 31.9% patients with symptomatic recurrence at an average of 2.6 years after initial decompression. Fibrotic thickening overlying the dura mater was observed in one-third of these patients.ConclusionsThis case series reports low complication but high long-term symptomatic recurrence rates adults with symptomatic Chiari-1 malformation undergoing PFD.