Comparative Assessment of Three Posterior Fossa Decompression Techniques and Evaluation of the Evidence Supporting the Efficacy of Syrinx Shunting and Filum Terminale Sectioning in Chiari Malformation Type I. A Systematic Review and Network Meta-Analysis

This study aimed to compare the effectiveness of posterior fossa decompression (PFD), posterior fossa decompression with duraplasty (PFDD), and posterior fossa decompression with resection of tonsils (PFDRT) in Chiari malformation type I (CMI). Furthermore, we aimed to evaluate the evidence supporting the efficacy of filum terminale sectioning (FTS), syringosubarachnoid shunting (SSS), and syringoperitoneal shunting (SPS) in CMI. PubMed, Cochrane, and Embase databases were screened for English-language studies published from inception until August 11, 2020. A total of 3593 studies were identified through the searching process. Fifteen cohort studies were included in the systematic review and network meta-analysis. No studies concerning FTS, SSS, and SPS were found eligible. Therefore, only PFD, PFDD, and PFDRT were compared. PFDD showed significantly higher incidence of complications (relative risk [RR], 3.79; 95% confidence interval [CI], 2.54–5.64) cerebrospinal fluid leak (RR, 9.74; 95% CI, 2.33–40.78) and neurologic deficit (RR, 8.76; 95% CI, 2.08–36.90) than did PFD. Both PFDD and PFDRT achieved higher syringomyelia improvement (RR, 1.23, 95% CI, 1.09–1.39 and RR, 1.32, 95% CI, 1.15–1.51, respectively) and greater clinical improvement (RR, 1.24, 95% CI, 1.10–1.39 and RR, 1.24, 95% CI, 1.08–1.44, respectively) than did PFD. No differences were found between PFDD and PFDRT. PFDD and PFDRT are superior to PFD, especially in patients with syringomyelia-Chiari complex, because of greater syringomyelia reduction and better clinical improvement. However, PFDD and PFDRT can be considered equally efficient. There is no evidence pleading in favor of SFT, SSS, and SPS over any PFD technique.