Analysis of the cervical double transverse foramen in present Spanish population

The aim of our study was to investigate the prevalence and morphometry of double transverse foramina in cervical vertebrae in a living population and to discuss their clinical importance. This is a retrospective single-center study. 253 (84.3%) computed tomography scan images of the cervical spine were collected from a total sample of 300 Spanish subjects that underwent a computed tomography study, 173 from men (68.3%) and 80 from women (31.6%), aged between 18 and 90 years old. The presence or absence of a double transverse foramen of each cervical vertebra was recorded, and the maximum right-left diameter, maximum antero-posterior diameter and area of each transverse foramen were measured. The applied statistics were multivariate models for repeated measures, Student t test and Pearson’s chi-squared test.Double transverse foramina in C4, C5, C6 and C7 were observed, the most prevalent being in C6 (45.8%), followed by C5 (23.5%), C4 (4.7%) and C7 (4.3%). The unilateral formation was significantly the most frequent. No differences were found based on sex. In the vertebrae with a double transverse foramen, the principal transverse foramen was significantly larger than the accessory transverse foramen. However, in these vertebrae the principal transverse foramen was significantly smaller when compared with the transverse foramen of normal vertebrae.C6 presents the greatest prevalence of double transverse foramina, although they are also observed in C4, C5 and C7. The double transverse foramen causes the principal transverse foramen to be smaller when compared with normal vertebrae, thus it should be taken into account in clinical practice.