Clinical and Technical Outcomes of Intracranial-Intracranial Bypass for Treating Complex Intracranial Aneurysms: An Analysis of 255 Patients.

Background: Despite the recent increase in publications centered on intracranial-intracranial (IC-IC) bypasses for complex aneurysms, there is no systematic evidence regarding their outcomes. The purpose was to assess the outcomes of patients subjected to IC-IC bypass for aneurysms.

Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis, a systematic review was conducted. Criteria for inclusion entailed studies with a cohort of at least 4 patients having undergone IC-IC bypass for aneurysms, detailing at least one outcome, such as patency, clinical outcomes, complications, and procedure-related mortality. When the study included patients who had undergone extracranial-intracranial (EC-IC) bypass, the authors extracted the patency and clinical data to juxtapose them with the results of IC-IC.

Results: Of the 2509 shortlisted studies, 22 met our inclusion criteria, encompassing 255 patients and 263 IC-IC bypass procedures. The IC-IC bypass procedure exhibited a patency rate of 93% (95% confidence interval [CI]: 89%-95%). The patency rate of IC-IC and EC-IC bypasses did not significantly differ (odds ratio=0.60 [95% CI: 0.18-1.96]). Concerning clinical outcomes, 91% of the IC-IC patients had positive results (95% CI: 85%-97%), with no significant disparity between the IC-IC and EC-IC groups (odds ratio=1.29 [95% CI: 0.43-3.88]). After analysis, the complication rate was 11% (95% CI: 5%-18%). Procedure-related mortality was 1% (95% CI: 0%-4%).

Conclusions: IC-IC bypass is valuable for the treatment of complex intracranial aneurysms, boasting high patency and positive clinical outcomes. Complications are unusual, and procedure-related mortality is minimal. Comparing IC-IC and EC-IC led to no significant differences.