Objective To systematically evaluate posterior fossa decompression with duraplasty (PFDD) and posterior fossa decompression without duraplasty (PFD) for Chiari malformation type I (CM-I). Methods A meta-analysis was performed according to the guideline of the MOOSE statement. Relevant literature and references were electronically searched in CENTRAL, Science Citation Index Expanded, MEDLINE (Ovid), PubMed, CBM, CNKI and WanFang Data from 1993 to September 2011. Two reviewers independently identified literature according to inclusion and exclusion criteria. The included studies were evaluated using the Newcastle-Ottawa Scale. Original data were extracted and analyzed using RevMan 5.1 software. Besides, the level of evidence was assessed using the GRADE system. Results Ten studies involving 829 patients were included. The results of meta-analyses showed that: a) compared with patients undergoing PFD, patients undergoing PFDD had a significantly lower reoperation rate (RR=0.41, 95%CI 0.23 to 0.74, P=0.003), and a higher rate of syringomyelia decrease (RR=1.27, 95%CI 1.03 to 1.56, P=0.02). But there was no significant difference in clinical improvement (RR=1.11, 95%CI 0.95 to 1.28, P=0.18). b) compared with PFD, patients undergoing PFDD had a higher rate of cerebrospinal fluid–related complications (RR=6.3, 95%CI 2.71 to 14.67, Plt;0.000 1). There were no significant differences in the complication of occipital neuralgia and wound infection (Pgt;0.05). Based on GRADE system, the evidence was at Level C and we made a weak recommendation. Conclusion Posterior fossa decompression with duraplasty is associated with a lower risk of reoperation, a better effect of syringomyelia decrease and a greater risk for cerebrospinal fluid–related complications, compared with PFD. Due to the influencing factors of lower-quality included studies, a prudent choice is suggested, and also more high-quality, large-sample studies are need.
