Brainstem Cavernous Malformations: A Systematic Review and Meta-Analysis.

[BACKGROUND] Brainstem cavernous malformations (BSCMs) are rare yet high-risk vascular lesions with a complex clinical course due to their eloquent location. Optimal treatment remains a topic of debate. This review aims to evaluate the outcomes of different management strategies for BSCMs, with a focus on rebleeding, functional recovery, and mortality.

[METHODS] Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, databases, including PubMed and Scopus, were searched. Data from 45 studies were analyzed using crude and pooled estimates. We used meta-regression to predict outcomes and adjust for heterogeneity. The risk of bias was assessed using the Risk Of Bias In Non-randomized Studies of Interventions -I and Risk Of Bias In Non-randomized Studies of Interventions-II tools.

[RESULTS] This meta-analysis included 45 studies with 3070 patients: 1928 underwent surgery, 543 radiosurgeries, and 599 conservative treatments. Surgery had the lowest recurrence (1.1%), rebleeding (3.3%), retreatment (1.3%), and mortality (1.4%) rates. Radiosurgery showed moderate rates (recurrence 4.4%, rebleeding 7.0%, and retreatment 4.1%), while conservative management had the highest rebleeding (26.3%) and mortality (3.2%). Functional improvement (modified Rankin Scale [mRS]) was highest in the surgical group (60.2%) versus radiosurgery (28.3%) and conservative care (35.7%). Larger lesion size significantly predicted worse mRS improvement (P = 0.007) and higher mortality (P = 0.02), especially in radiosurgical patients.

[CONCLUSIONS] Our findings largely reflect the cohort of hemorrhagic or symptomatic BSCMs for which microsurgical resection is generally associated with more favorable outcomes, including lower rates of recurrence, rebleeding, and mortality, when compared with radiosurgery and conservative care. Caution is warranted in extrapolating to incidental or asymptomatic lesions. Future research should also integrate advanced imaging and molecular approaches to refine risk stratification and guide management.