Incidental thoracic OLF (ossification of ligamentum flavum) in 2134 Korean patients with back pain : incidence, distribution and its significance

Abstract

Ossification of the ligamentum flavum (OLF) is a rare disease in which the pathogenesis has been conclusively established. The epidemiology of OLF remains obscure. In Korea, to date, there is no study that has comprehensively evaluated thoracic OLF by MRI to assess the incidence rate and distribution of thoracic OLF in a large enough sample size with coexisting spinal disease. This study targeted 2134 patients who underwent MRI evaluation for back pain or leg pain. We found the incidence of thoracic OLF for patients with lumbar problems to be 16.9%. The incidence rate tended to increase with aging and was higher in women than in men. The lower thoracic segment of T10-11 was the most frequent segment. Coexisting herniated thoracic discs (HTD) at the same level was 31.9% in 360 OLF patients. Approximately 70% of the 360 OLF patients had coexisting lumbar and cervical disease.