RESUMEN
Background: Postoperative cerebrospinal fluid (CSF) leak is a major concern after posterior fossa surgery with significant clinical implications. It has been postulated that replacing the bone flap, performing a craniotomy, would reinforce the surgical closure and decrease rates of CSF leak. This systematic review and meta-analysis compared the rate of CSF leak after posterior fossa craniotomies versus craniectomies. Methods: Three databases were searched for English studies comparing the primary outcome, rate of CSF leak, after adult posterior fossa craniotomies versus craniectomies. Secondary outcomes included the rate of postoperative pseudomeningocele formation, CSF leak and pseudomeningocele formation, CSF diversion, revision surgery, and infection. Pooled estimates and relative risks for dichotomous outcomes were calculated using Review Manager 5.4, with corresponding 95% confidence intervals (CIs). Results: A total of 1250 patients (635 craniotomies and 615 craniectomies), from nine studies, were included in the final analysis. Even though rates of CSF leak favored craniotomies, the difference did not reach statistical significance in our pooled analysis (Risk Ratio: 0.71, 95% Confidence Interval: 0.45-1.14, p-value = 0.15, Heterogeneity I-squared = 0%). On the other hand, comparing the rates of pseudomeningocele formation and CSF leak, as a combined outcome, or pseudomeningocele formation only showed a significant difference favoring craniotomies. The quality of evidence in this meta-analysis was graded as having a high risk of bias based on the risk of bias in non-randomized studies - of exposure criteria. Conclusion: Based on evidence with high risk of bias, rates of postoperative CSF leak and pseudomeningocele formation favored posterior fossa craniotomies over craniectomies. Further research with more robust methodology is required to validate these findings.
RESUMEN
BACKGROUND: Stereotactic brain biopsy techniques have been a focus of rapid technological innovation. The recent advent of frameless stereotaxy has invited the question of whether it can provide the same diagnostic yield as frame-based techniques, without increasing risk of harm to patients. The goal of this meta-analysis was to compare each of these techniques in terms of yield and safety. METHODS: We independently searched four databases for English studies comparing frameless and frame-based stereotactic brain biopsies. Our primary outcome was biopsy diagnostic yield. Our secondary outcomes included mortality, morbidity (e.g., symptomatic postbiopsy intracranial hemorrhage, asymptomatic postbiopsy intracranial hemorrhage, new postbiopsy neurological deficit, and postbiopsy seizure), and frequency of repeat biopsy. We calculated pooled estimates and relative risks for dichotomous outcomes using Review Manager 5.3, with corresponding 95% confidence intervals. RESULTS: A total of 3256 stereotactic brain biopsies (2050 frame based and 1206 frameless), from 20 studies, were included in our final analysis. The results did not demonstrate any significant difference between the two stereotactic systems in terms of diagnostic yield (risk ratio [RR] 1.00, 95% confidence interval [CI] 0.99-1.02, P = 0.64, I2 = 0%). The only significant difference was the increased frequency of asymptomatic hemorrhages in the frameless group (RR 1.37, 95% CI 1.06-1.75, P = 0.01, I2 = 0%). Application of Grading of Recommendations Assessment, Development, and Evaluation to the results yielded very low quality of all outcomes. CONCLUSION: Based on very low-quality evidence, both frame-based and frameless stereotaxy are safe and effective for biopsy of intracranial tumors. Further study of patient preference and cost comparing analysis is required to identify if either modality should be preferred.