Possible Clinical Implications of Geographic Differences in Prevalence of Double Transverse Foramen

Background: The double transverse foramen (DBLTF) is a cervical spine anatomic variant. Current literature has presented prevalence values of DBLTF in Caucasian Mediterranean subjects that seem to be higher than those observed in other samples of subjects. Therefore we aimed to test if Caucasian Mediterranean subjects present a higher prevalence of the DBLTF than sub-Saharan African subjects. Methods: We analyzed the presence of DBLTF in cervical spines of 100 skeletons from Caucasian Mediterranean subjects and 91 skeletons from sub-Saharan African subjects, resulting in a total of 1337 cervical vertebrae having been studied. Results: No DBLTF was found in vertebrae C1, C2, and C3. The pattern of prevalence observed in all samples analyzed indicated the prevalence ranged from exhibiting the most to the least prevalence as C6 > C5 > C7 > C4. The sub-Saharan African subjects presented a significant reduced DBLTF prevalence of 2.2%, 14.3%, 19.8%, and 3.3% in C4 (P = 0.043), C5 (P = 0.004), C6 (P < 0.001), and C7 (P = 0.041), respectively, than that presented by Caucasian Mediterranean subjects (9.0%, 32.0%, 45.0%, 11.0% in C4, C5, C6, and C7, respectively). Conclusions: Our study has revealed that this anatomic variation is more frequently found in Caucasian Mediterranean subjects than in sub-Saharan African subjects.