Decompression with or without Duraplasty for Chiari I and Syringomyelia

Background: In children with Chiari type I malformation and syringomyelia, neurosurgical posterior fossa decompression (PFD) provides clinical improvement, but whether duraplasty (incising the dura and placing a dural graft) improves outcomes is unclear. Methods: We conducted a multicenter, cluster-randomized, controlled trial of PFD with duraplasty (PFD-D) as compared with PFD alone. Persons 21 years of age or younger with cerebellar tonsillar ectopia of at least 5 mm and a maximum syrinx diameter of 3.0 to 9.9 mm were enrolled at 38 centers. Centers were cluster-randomized: all the participants within each center underwent the same intervention. The primary outcome was surgical complications within 6 months. Secondary outcomes were clinical improvement, syrinx reduction, and repeat decompression at 10 to 24 months and the change in overall health-related quality of life at 6 to 24 months. Results: A total of 162 participants were included in the trial, of whom 78 were assigned to undergo PFD-D and 84 to undergo PFD alone. The percentage of participants with complications within 6 months was 14% with PFD-D and 6% with PFD (adjusted odds ratio, 2.59; 95% confidence interval [CI], 0.86 to 7.84; P = 0.11). At 24 months, the percentage of participants with clinical improvement was 58% with PFD-D and 46% with PFD; the mean (±SD) syrinx reduction was 3.08±2.33 mm and 1.22±1.79 mm, respectively; and the percentage of participants with repeat decompression was 3% and 14%. Changes in