Imaging in Thoracic Disc Prolapse: A Study of 25 Patients and Review of Literature

Abstract

Purpose: Unlike cervical and lumbar disc, thoracic disc prolapse (TDP) has limited literature. Many studies have focused on surgical technique of TDP. The aim of this study is to highlight the radiological features of TDP that would help surgeons in understanding the peculiar features of such uncommon entity and also planning the surgery. Materials and Methods: All the patients surgically treated for TDP between May 2010 and June 2018 were included in the study. A retrospective collection of all the radiographs, CT and MR images were done. Results: A total of 25 subjects, two patients had double level disc prolapse; hence, a total of 27 discs were analyzed. On radiographs, end-plate was concave (n = 9), straight (n = 12), cupid bow shaped (n = 6), calcification in disc space (n = 5), and calcification within the canal (n = 14). EP junction failures were type IA (n = 10), type IB (n = 6), type ID (n = 2), and type II (n = 9). On MRI, central disc prolapse (n = 10), right paracentral (n = 12), and left paracentral (n = 5). According to Pfirmann grading, three discs were Grade 2; five discs as Grade 3; 14 as Grade 4; and five as Grade 5. Fourteen discs had >40% canal occupancy. Schmorl nodes were noted (n = 17). Conclusion: Lower thoracic spine has a higher incidence of TDP. Calcification is commonly seen in cases of TDP, either in the disc space or within the canal. Most of the cases present with >40% of canal occupancy. End plate defect, a variant of schmorl node, may be a possible contributor to disc prolapse. Keywords: Thoracic disc prolapse, radiology, calcification.