Does Ossification of the Posterior Longitudinal Ligament Affect the Neurological Outcome After Traumatic Cervical Cord Injury?

Abstract

Retrospective outcome measurement study. The purpose of this study is to assess whether ossification of the posterior longitudinal ligament (OPLL) affects neurologic outcomes in patients with acute cervical spinal cord injury (SCI). There have so far been few reports examining the relationship between OPLL and SCI and there is controversy regarding the deteriorating effects of OPLL-induced canal stenosis on neurologic outcomes. To obtain a relatively uniform background, patients nonsurgically treated for an acute C3-C4 level SCI without any fractures or dislocations of the spinal column were selected, resulting in 129 patients. There were 110 men and 19 women (mean age was 61.1 years), having various neurologic conditions on admission (American Spinal Injury Association [ASIA] impairment scale A, 43; B, 16; C, 58; D, 12). The follow-up period was the duration of their hospital stay and ranged from 50 to 603 days (mean, 233 days). The presence of OPLL, the cause of injury, the degree of canal stenosis (both static and dynamic), and the neurologic outcomes in motor function, including improvement rate, were assessed. Of the 129 patients investigated in this study, OPLL was identified at the site of the injury in 13 patients (10.1%). In this OPLL+ group, the static and dynamic canal diameters at C3 and C4 were significantly smaller than those of the remaining 116 patients (OPLL- group). However, no significant difference was observed between the 2 groups in terms of ASIA motor score both at the time of administration and discharge, and the mean improvement rate in ASIA motor score was 55.5 +/- 9.0% in OPLL+ group, while it was 43.1 +/- 2.8% in the OPLL-group. Furthermore, no significant correlation was observed between the static/dynamic canal diameters and neurologic outcome in all 129 patients. No evidence was found for OPLL to have any effect on the initial neurologic status or recovery in motor function after traumatic cervical cord injury, suggesting that the neurologic outcome is not significantly dependent on canal space.