Osteophytes' position in subjects with DISH and right-sided aorta: Verification of the 'aortic pulsation protective effect' theory

Objectives: To validate in a large cohort with right-sided aorta the theory that thoracic right-sided flowing osteophytes in DISH results from a 'protective' effect of the pulsating descending left-sided thoracic aorta. Methods: Chest CTs of patients with DISH and right-sided aorta and controls with DISH and left-sided aorta were evaluated and compared on each intervertebral space (IS) for the location of the aorta (right, left, centre) and the location of the osteophyte relative to the aorta (contralateral, ipsilateral, bilateral). Results: The study and control cohorts included 31 and 35 subjects, respectively (male 22/9 and female 27/8; median age 64.8/65.3 years; P = 0.86). Osteophytes contralateral to the aorta's location were recorded in the majority of ISs in both the study and control groups (47% and 60%, respectively; P > 0.05), while ipsilateral osteophytes were recorded in 6.9% and 7.7%, respectively (P = 0.002). Bilateral osteophytes located to the right and the left of the aorta were significantly more prevalent in the study group compared with the controls (17.2% and 5.4%, respectively; P = 0.04). Conclusions: Aortic pulsation plays an important role in inhibiting the development of osteophytes and results in the majority of contralateral osteophytes on both right-sided and left-sided aortas. However, since both ipsilateral and bilateral osteophytes were not at all rare in both groups, other parameters, which are yet to be established, probably contribute to the location of osteophytes.