A higher frequency of lumbar ossification of the posterior longitudinal ligament in elderly in an outpatient clinic in Japan

PURPOSE: Little is known about the prevalence and epidemiological characteristics of lumbar ossification of the posterior longitudinal ligament (OPLL). We analyzed the rate of lumbar OPLL in an outpatient unit where primary care physicians are working in Japan, to better understand the epidemiological characteristics of the disease. METHODS: We analyzed consecutive, first-time visiting outpatients who received abdominal and pelvic computed tomography (CT) scan at the Department of General Medicine, Asahikawa Medical University Hospital, Japan, between April 2009 and March 2012. Each parameter such as age, sex, and clinical presentation was investigated. RESULTS: Out of 393 patients who underwent abdominal and pelvic CT scan, 33 (8.4%) were diagnosed as lumbar OPLL. When compared with patients without lumbar OPLL (n = 360), there was no significant difference in gender, body mass index (BMI), presence of hypertension, diabetes mellitus or hyperlipidemia, and smoking habit, while the age in patients with lumbar OPLL was significantly higher. CONCLUSION: These results suggest for the first time that lumbar OPLL is frequently observed in elderly people in the primary care setting, in Japan.