Presence of a foramen arcuale as a possible cause for headaches and migraine: Systematic review and meta-analysis.

The foramen arcuale (FA) is an osseous bridge that can be formed on the posterior arch of the atlas, often observed on lateral radiographs of the cervical spine. Currently, there is a lack of studies that systematically review the available literature on the FA and its role in headaches and migraines. Therefore, we conducted an extensive search of the major electronic databases to identify all studies that reported relevant data on patients with versus without FA and prevalence of headaches or migraines. No date or language restrictions were applied. Data on the prevalence, type (complete and incomplete), and laterality of the FA and relationship with headaches or migraines were extracted and pooled into a meta-analysis. There were 168/412 (40.8%) patients with headaches in the FA group compared to 368/1691 (21.8%) patients with headaches in the no FA group (OR 4.68; P = 0.002). The proportion of headaches for complete FA was 73/125 (58.4%) compared with 80/413 (19.4%) for incomplete FA (OR 5.04; P = 0.04). When comparing incomplete FA to no FA, the proportion of headaches was 36/85 (42.3%) vs 65/560 (11.6%), and this was significantly different (OR 6.13; P = 0.009). The proportion of headaches in patients with bilateral FA was 67/132 (50.8%) compared to 80/140 (57.1%) in the unilateral group (OR 1.36; P = 0.72). We performed the first meta-analysis to demonstrate the significant association between FA and headaches, and provided further support for the notion of the clinical relevance of this anatomical variant.