Longitudinal study of ossification progression in patients with cervical ossification of the posterior longitudinal ligament using a three-dimensional analysis.

Abstract

PURPOSE: This study aimed to investigate the mechanism of progression in ossification of the posterior longitudinal ligament (OPLL) by conducting a longitudinal three-dimensional (3D) quantitative analysis and comparing the effects of different treatment conditions, including non-surgical management, laminoplasty, and fusion. METHODS: Eighty-five patients with cervical OPLL were divided into a non-surgical group (N group, n = 30), a laminoplasty group (LP group, n = 35), and a posterior decompression and fusion group (F group, n = 20). The OPLL volume was measured three times using computed tomography-based 3D analysis during a mean follow-up of 43.6 months. The annual rate of increase in OPLL volume was calculated and compared among the groups. RESULTS: The annual rates of increase were 3.8%, 6.2%, and 2.1% in the N, LP, and F groups, respectively. The annual rate of increase of the F group was significantly lower than that in the LP group (p < 0.01). Rapid progression (> 10% annual rate of increase) occurred in 10%, 20%, and 0% of patients in the N, LP, and F groups, respectively. Only the F group showed a significant reduction in the annual rate of increase over time (from 2.8% to 1.3%, p < 0.05). CONCLUSION: Fusion may suppress OPLL progression by stabilizing the cervical spine, suggesting its clinical relevance in surgical decision-making. In contrast, laminoplasty tended to maintain ossification growth, with several patients exhibiting continued rapid progression, highlighting the need for careful postoperative monitoring.