Pathogenesis of myelopathy in patients with ossification of the posterior longitudinal ligament

Abstract

Study DesignThis was a prospective study with an average 11-year follow-up review. Clinical and radiographic changes in Object. The goal of this study was to clarify the pathogenesis of myelopathy in patients with ossification of the posterior longitudinal ligament (OPLL) based on the relationship between static compression factors and dynamic factors.Methods. There was a total of 247 patients, including 167 patients who were conservatively followed for a mean of 11 years and 2 months and 80 patients who had myelopathy at initial consultation and underwent surgery. The changes in clinical symptoms associated with OPLL in the cervical spine were examined periodically.During the natural course of OPLL in the cervical spine, 37 (22%) of 167 patients developed or suffered aggravated spinal symptoms. All of the patients with a space available for the spinal cord (SAC) less than 6 mm suffered myelopathy, whereas the patients with an SAC diameter of 14 mm or greater did not. No correlation was found between the presence or absence of myelopathy in patients whose SAC diameter ranged from 6 mm to less than 14 mm. In patients with myelopathy whose minimal SAC diameter ranged from 6 mm to less than 14 mm, the range of motion of the cervical spine was significantly greater.Conclusions. These results indicate that pathological compression by the ossified ligament above a certain critical point may be the most significant factor in inducing myelopathy, whereas below that point dynamic factors may be largely involved in inducing myelopathy. KEY WORDS • ossification of the posterior longitudinal ligament • myelopathy • spinal cordA J. Neurosurg: Spine / Volume 96 / March, 2002 Abbreviations used in this paper: OPLL = ossification of the posterior longitudinal ligament; ROM = range of motion; SAC = space available for the spinal cord.

Spinal cord cross-sectional area during flexion and extension in the patients with cervical ossification of posterior longitudinal ligament

“…Matsunaga et al [6] also reported that during the natural course of OPLL in the cervical spine, 37 (22 %) of 167 patients developed or suffered from aggravated spinal symptoms. All patients with less than 6 mm space available for the spinal cord (SAC) suffered from myelopathy, whereas patients with 14 mm or greater did not.…”

Osteogenic lineage commitment of mesenchymal stem cells from patients with ossification of the posterior longitudinal ligament

“…Ossification of this ligament is characterized by ectopic bone formation, and is frequently linked with similar ossification in other surrounding spinal ligaments. These ossified lesions often enlarge with time and compress the spinal cord and its roots, leading to neurological deficiencies and a high risk of spinal cord injury [1,2]. Patients with severe symptoms are considered definitive candidates for surgical treatment such as spinal decompression [3].…”

Diffusion tensor imaging in the assessment of ossification of the posterior longitudinal ligament: a report on preliminary results in 3 cases and review of the literature

“…8,19 As the spinal cord becomes compressed by ossified or hypertrophied ligament and bone spurs, the cushioning effect of CSF is lost. In a series of 200 patients seeking treatment for CSS, 63 (31.5%) reported an episode of minor trauma in the preceding 2 weeks.…”