Direct anterior decompression in patients with ossification of the posterior longitudinal ligament significantly relieves short-segment spinal cord high signal.

Background: In patients with ossification of the posterior longitudinal ligament of the cervical spine (OPLL), high spinal cord signal (HCS) is frequently observed in the spinal cord of the corresponding segment. However, studies on the differences in the improvement of high spinal cord signal due to different surgical approaches are limited. The aim of this study was to investigate the improvement of high spinal cord signal in long and short segments with different choices of surgical approaches.

Methods: In this study, we conducted a meticulous review of medical records for patients diagnosed with ossification of the posterior longitudinal ligament (OPLL). Demographic variables, including gender, age, and body mass index (BMI), were systematically recorded. We evaluated the severity of neurological impairment using the Japanese Orthopaedic Association (JOA) scores both preoperatively and at multiple postoperative follow-up points. Neurological assessments were complemented by serial magnetic resonance imaging (MRI) T2-weighted imaging (T2WI) to measure the extent of high-signal changes (HCS) in the spinal cord, and the alteration of the HCS was quantified by the SCR (the ratio between the signal intensity value of the HCS region and the signal intensity value of the normal spinal cord region at C7-T1).

Results: In the short-segment high signal change (HCS) group, comparisons of JOA score improvement (Recovery1) and HCS improvement (CR1) at 6 months postoperatively did not demonstrate significant differences between the surgical approaches (P > 0.05; Table 1). However, at the 2-year follow-up, patients who underwent anterior surgery exhibited significantly greater improvements in both JOA scores (Recovery2) and HCS (CR2), with statistical significance achieved (P < 0.05; Table 1). In contrast, in the long-segment HCS group, there was no significant difference between the anterior and posterior surgical approaches in terms of JOA improvement and HCS improvement at 6 months and 2 years postoperatively (P > 0.05; Table 2).

Conclusions: In patients with OPLL who present with spinal cord high signal, anterior surgery by resection of the ossified posterior longitudinal ligament and direct decompression is more conducive to regression of small spinal cord high signal and improvement of clinical neurological function if the extent of spinal cord high signal is small.