The Prevalence of Termination Variations of the Basilar Artery:A Systematic Review and Meta-Analysis

Purpose: Understanding the vascular anatomical variations of the termination pattern of the basilar artery is crucial for both neurosurgical and interventional radiological procedures. Recent evidence indicates that variant bifurcation patterns of the basilar artery, differing from the classical textbook descrip- tion, are increasingly encountered. This study aims to provide a comprehensive summary of the prevalence of termination anomalies related to the basilar artery.<br/>Methods: This systematic review included human cadaveric and imaging studies on basilar artery termination patterns. PubMed, Ovid MEDLINE, and Scopus databases were system- atically searched in accordance with PRISMA guidelines, us- ing the terms “(basilar OR vertebrobasilar OR (posterior AND circulation)) AND (anatomy OR termination OR trifurcation OR quadfurcation OR pentafurcation OR hexafurcation OR nonfurcation OR variation OR variant)”. A meta-analysis of proportions was conducted to assess the prevalence of each variation using a random intercept logistic regression model, following logit transformation of the proportions.<br/>Results: From 845 initial hits, 4 articles were eligible for the quantitative analysis. The estimated pooled proportions of bifurcation, trifurcation, quadfurcation, pentafurcation, hexa- furcation, and non-furcation in the artery, under the random effects model, were 62.22% (95%CI [34.48%; 83.75%]), 6.08% (95%CI [2.60%; 13.58%]), 5.27% (95%CI [2.17%; 12.27%]),2.06% (95%CI [0.96%; 4.35%]), 0.49% (95%CI [0.08%; 2.90%]), and 0.10% (95%CI [0.0%; 17.07%]), respectively. Heterogeneity analysis revealed significant variability among the studies (I2 up to 93.6%, p&lt;0.0001).<br/>Conclusion: More than one-third of basilar artery termi- nations exhibit anatomical variations other than bifurcation. Trifurcation and quadfurcation are the most commonly re- ported variations, each accounting for over 5% of cases. These variations might carry significant implications for regional neurosurgical and interventional radiological procedures.<br/>