What are the possibilities of spontaneous resorption of a thoracic disc herniation occupying more than 20% of the spinal canal in the asymptomatic subject? Comparative study.

Thoracic disc herniation is a rare pathology for which surgical treatment is difficult. The discovery of asymptomatic or only slightly symptomatic lesions can be problematic, especially in cases of marked canal stenosis. The possibility of spontaneous resorption has been documented by a few case reports but there is no study on this subject. Our objective was to compare the clinical and radiological data for two groups of patients with significant thoracic herniation (occupying more than 20% of the spinal canal): one showing spontaneous resorption (group 1) and the other persistence of the lesion during follow up (group 2). The physiological processes of thoracic herniation are also discussed. We present a retrospective study of our database of patients with thoracic hernia. Only subjects who initially showed signs of slight or absent myelopathy (Frankel D or E) were included. Group 1 and 2 are composed of 12 and 17 patients respectively. The clinical and radiological data are compared. The two groups were not different for the following parameters: age, sex ratio, disc calcification, size, trajectory, side, hernia level. Other parameters were evaluated and were not associated with a higher rate of resorption: disc calcification, intramedullary hypersignal in T2 sequence, calcification of the posterior common vertebral ligament, calcification of another disc and Scheuerman's disease. Asymptomatic thoracic disc herniation is a condition that can disappear spontaneously, even in the case of a large lesion. To date, there are no clinical or radiological data that can predict such an evolution.