Predictive potential of radiographic characteristics on outcomes after Chiari Decompression surgery: A meta-analysis of the literature.

BACKGROUND: Chiari malformation type 1 (CM-1) occurs in approximately 0.5-3.5 % of the general population. Severity of CM-1 radiographic findings can vary with regards to syrinx size, hydrocephalus, and degree of tonsillar herniation. This systematic review and meta-analysis analyzes the impact of radiographic characteristics on clinical outcomes in adult and pediatric patients undergoing CM-1 decompression surgery. METHODS: A systematic review was conducted using PubMed/MEDLINE, Embase, Web of Science, and Cochrane Library databases, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies focusing on predictive outcomes related to CM-I and decompression surgery, with radiographic findings reported, were included. Study quality was assessed using the Joanna Briggs Institute critical appraisal tool. RESULTS: A total of 51 observational studies were included, collectively reporting 144 unique radiographic findings. The presence of syringomyelia was evaluated in 30 studies, with five studies reporting positive outcomes, 13 reporting neutral outcomes, and 12 reporting negative outcomes. The severity of tonsillar descent/herniation was assessed in 31 studies, with 23 reporting neutral outcomes, six reporting negative outcomes, and only two reporting positive outcomes. The pB-C2 line length was analyzed in 10 studies, showing one positive, eight neutral, and one negative outcomes. Improvement in cerebrospinal fluid (CSF) flow was evaluated in 12 studies, with eight reporting positive outcomes and four reporting neutral outcomes. Surgical techniques varied across studies, particularly regarding the use of duraplasty and tonsillar reduction. Meta-analysis identified CSF flow restoration as a significant predictor of surgical success, with a positive outcome proportion of 66.7 %, outperforming other parameters. In contrast, tonsillar descent and syringomyelia were more commonly found to have no impact on outcomes. CONCLUSIONS: The findings gleaned from this review highlight the importance of careful preoperative assessment of radiographic markers and the role of restoring CSF dynamics in CM-1 patients undergoing posterior fossa decompression. The most significant limitation of this systematic review is the quality of the articles included in this study, as most are single arm observational studies and have considerable risk of bias. Our results also must be interpreted accounting for the heterogeneity in surgical techniques across the included studies. The findings of the present study could ultimately help physicians optimize the surgical decision-making process and prognostication considerations in the CM-1 patient population.

Duke Scholars

Author Carrie Rebecca Muh Neurosurgery