Radiologic analysis of ossification of the posterior longitudinal ligament of the spine

Since calcification or ossification of the posterior longitudinal ligament of the spine was first described inJapan in 1960 by Tsukimoto, Terayama used the term of OPLL(Ossification of Posterior Longitudinal Ligament) in1964 and mainly reported in Japanese. But recently, the incidence of the OPLL has been reported increasing amongthe non-Japanese. Because of the OPLL may be associated wtih severe neurologic symptoms, which need to havesurgical decompression, exact diagnosis and analysis are necessary. The OPLL can be diagnosed by simple spine,conventional tomography, myelography and CT. Authors analysed radiologic findings of the OPLL in 8 patients, whowere diagnosed by simple spine. Conventional tomography, myelography and CT, and then performed spinal operation,at Hanyang University Hospital from March 1980 to June 1983. The results were as followings; 1. The age range wasbetween 45 and 63 years and most prevalent age was 6th decades(63%). 2. All of the patients were male. 3. All ofthe OPLL occurred in the cervical spine and predominant at the level of C3,4 (48%). 4. The most common length ofthe OPLL was 2 vertebral level. 5. Except one, which was discontinuous at the level of disc space, all of the OPLLwere continuous in length. 6. 7 of 8 OPLL were located in the midline, but one was in right. 7. The OPLL seemed tocorrelate with spondylotic changes. 8. Of all diagnostic procedure, CT provided better and exact visualization ofthe lesion with axial scan and sagittal reconstruction.