Simultaneous ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum causing upper thoracic myelopathy in DISH: case report and literature review.

A rare case of a 44-year-old Chinese male with diffuse idiopathic skeletal hyperostosis (DISH) and simultaneous ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) at T1-2 causing thoracic myelopathy is reported herein. Posterior decompression without extirpating the OPLL was performed at T1-2. Postoperatively, symptoms were greatly improved, with remaining hyperreflexia and Grade 4/5 muscle strength in the lower extremities. The Japanese Orthopedic Association score improved from 5 preoperatively to 9 at final follow-up. The presence of a cyst due to leakage of cerebrospinal fluid was confirmed by MRI at day 27, but it resolved after conservative management. The clinical manifestation of DISH, the relationship among DISH, OPLL, and OLF, and management of thoracic myelopathy due to OPLL and OLF were reviewed.