Anatomical variants of the vertebral artery and their relationship with craniocervical disorders and surgical considerations: a systematic review and meta-analysis.

The vertebral artery (VA) supplies almost one-third of the blood flow to the brain, contributing mainly to its posterior circulation. This article provides a comprehensive overview of the different anatomical variations related to the origin, course, and termination of the VA and associated clinical implications. Data were compiled from numerous published studies accessed from the databases Medline, Scopus, Web of Science, Google Scholar, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Literature in Health Sciences (LILACS) as of January 2024. Methodological quality was evaluated with an assurance tool for anatomical studies (AQUA). Pooled prevalence was estimated using a random effects model, and differences in VA variant rates were assessed. VA variants were identified that could be separated into three categories: variation in origin, course, and terminal branches. A total of 16 studies met the established selection criteria for the current meta-analysis. VA variations were reported at an overall prevalence of 11% (CI: 7%-15%) and a heterogeneity of 77%. Statistically significantly higher rates were revealed in the following subgroups of the sample: imaging examinations versus cadavers (p = 0.032); right side of the body versus left (p = 0.034); and bilaterally versus unilaterally (p = 0.019). Concerns listed in included studies primarily focused on the possibility of iatrogenic damage during surgical procedures. A few studies also indicated higher rates of VA variants in patients who reported symptoms of recurrent headaches, vertigo, dizziness, and/or syncope. The presence of VA variants is high and can occur in various regions. However, the most important clinical consideration is that individuals with this variant must be constantly monitored since their posterior cerebral circulation could be affected. To avoid iatrogenic damage to the VA, clinicians should employ medical imaging to evaluate its course and branches prior to surgical interventions in the region.