Objective: Patients with ossification of the posterior longitudinal ligament (OPLL) sometimes present with acute spinal cord injury caused by only minor trauma. In the present study, we reviewed our experience of acute cervical cord injury associated with OPLL to understand the pathomechanisms and to provide clinical information for management of this disorder.
Methods: Twenty-eight patients were retrospectively analyzed. There were 26 men and 2 women, aged 45 to 78 years (mean, 63.0 yr). Most patients experienced incomplete spinal cord injury (Frankel Grade A, 3; B, 1; C, 15; and D, 9).
Results: Radiological studies revealed continuous- or mixed-type OPLL in 14 patients and segmental-type OPLL in 14 patients. The sagittal diameter of the spinal canal was reduced to 4.1 to 10 mm at the narrowest level as a result of OPLL. Developmental size of the spinal canal was significantly smaller in the group with segmental OPLL. Magnetic resonance imaging scans revealed that spinal cord injury occurred predominantly at the caudal edge of continuous-type OPLL or at the disc levels. Surgery was performed in 24 patients either by posterior (18 patients) or anterior (6 patients) decompression at various time intervals after the trauma. Twenty patients (71%) displayed improvement in Frankel grade.
Conclusion: The present study demonstrates the preexisting factors and pathomechanisms of acute spinal cord injury associated with cervical OPLL. Magnetic resonance imaging is useful to understand the level and mechanism of injury. Further investigation will be needed to elucidate the role of surgical decompression.