Arcuate Foramen of the Atlas Vertebra and its Correlation with Clinical Implications in the Craniocervical Region: A Systematic Review and Meta-analysis

BACKGROUND CONTEXT: The arcuate foramen (FA) can present in various forms: it may be complete, incomplete, unilateral, or bilateral. This anatomical feature is relatively common, occurring in approximately 3-15% of the population, with a higher prevalence in females.

PURPOSE: The purpose of this study is to provide rigorous scientific evidence detailing the anatomical characteristics of the AF. Furthermore, this work aims to analyze the prevalence and explore its relevance in clinical applications and surgical procedures.

STUDY DESING: Systematic review and meta-analysis METHODS: Data were compiled from numerous published studies accessed from the databases Medline, Scopus, Web of Science, EMBASE, Google Scholar, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and of April 2025. Methodological quality was evaluated with an assurance tool for anatomical studies (AQUA). Pooled prevalence was estimated using a random effects model, and differences in FA variant rates were assessed.

RESULTS: FA variants were identified, the data were categorized into three groups: the first category was the type of sample, divided into cadaver donor samples and imaging findings; the second analysis focused on the geographical region from which the sample originated; and finally, sex and laterality were also considered. Overall, the prevalence of these variations was 16% (CI: 11%-20%), and significant heterogeneity (98.8%) was observed. Significantly higher rates were observed in the following subgroups: imaging studies versus donor data (p=0.032), right side versus left side (p=0.034), and bilateral versus unilateral findings (p=0.019). Among the concerns raised were studies on the risk of iatrogenic damage during surgical procedures. Several studies also indicated a higher frequency of vertebral artery variations in patients with symptoms such as recurrent headaches, vertigo, dizziness, and/or syncope.

CONCLUSION: This review emphasized the importance of considering the vertebral artery (VA) in the preoperative assessment of surgical procedures involving the placement of screws in the cervical spine, such as treatment for atlantoaxial instability. Lack of knowledge regarding the anatomy of this region can lead to complications, such as vertebral artery injury and, consequently, impaired blood flow to the brain, cerebellum, and brainstem. Therefore, the authors recommend further research on this topic, particularly in other patient populations and in collaboration with other disciplines, to advance our understanding of the vertebral artery and to provide valuable tools for healthcare professionals and researchers, thus contributing to improved patient care.