BACKGROUND: Posterior fossa decompression without (PFD) or with duraplasty (PFDD) for the treatment of type 1 Chiari malformation (CM-1) is controversial. We thus performed a systematic review and meta-analysis of studies to assess the effect on clinical and imaging improvement, operative time, complications, and recurrence rate between PFD and PFDD in patients with CM-1. METHODS: We systematically searched PubMed, Embase, Cochrane, Web of Knowledge, and ClinicalTrials. gov for retrospective or prospective studies comparing PFD with PFDD. Our main end points were clinical and imaging improvement, operative time, complications, and recurrence rate. We assessed pooled data by use of a fixed-effects or random-effects model according to the between-study heterogeneity. RESULTS: Of 214 identified studies, 13 were eligible and were included in our analysis (N=3481 patients). Compared with PFD, PFDD led to a mean greater increase in operative time than did PFD [standardized mean difference, -2.35; 95% confidence interval [CI], (-2.70 to -1.99)], a higher likelihood of clinical improvement in patients with syringomyelia (relative risk [RR], 0.70; 95% CI, 0.49-0.98), no increased RR of clinical improvement in patients without syringomyelia, no increased RR of imaging improvement, but an increased RR of cerebrospinal fluiderelated complications (RR, 0.29; 95% CI, 0.15-0.58), cerebrospinal fluid leak, aseptic meningitis, pseudomeningocele, and a decreased likelihood of recurrence rate. CONCLUSIONS: PFDD can be an optimal surgical strategy because of its higher clinical improvement and lower recurrence rate in the patients with syringomyelia. In patients without syringomyelia, PFD can be a preferred choice because of its similar clinical improvement and lower costs. Future randomized studies with large numbers and the power to provide illumination for surgical decision making in CM-1 are warranted.