Abstract: Objective To investigate the correlation of spinal canal stricture and intramedullary increased signal intensity (ISI) in patients with ossification of the posterior longitudinal ligament (OPLL). Methods 92 patients with OPLL were divided into 3 groups, those with the sagittal diameter remained ≥66.7% were as group A, 33.3%~66.7% as group B, and <33.3% as group C. The incidence of intramedullary ISI was recorded, and their neurological condition was assessed with the Japanese Orthopedics Association Assessment (JOA). Results ISI were found in 6 cases in the group A (20.7%), 17 cases in the group B (47.2%) and 19 cases in the group C (70.4%) (P<0.05). The score of JOA was (7.1±2.1) in the group A, (6.0±1.8) in the group B and (5.6±2.0) in the group C (P<0.05). Conclusion The incidence of intramedullary ISI increased with the severity of spinal canal stricture, and with more severe nerve damage in OPLL patients.

Key words: cervical spine, posterior longitudinal ligament, ossification, intramedullary increased signal intensity, neurological function