Purpose: To determine whether neural axis level of injury (SCI, CMI, or CEI) is related to motor improvement, as defined by the International Standards for Neurological Classification of Spinal Cord Injury motor score (MS), in patients with a thoracolumbar (T11-L3) spine injury.
Method: Fifty-three patients who sustained a neurological deficit secondary to a thoracolumbar spinal injury between 1995–2003 had injury details and MS collected prospectively. An independent evaluation determined the follow-up MS and SF-36 generic health-related quality of life (HrQOL) at a mean of 6.6 (SD 2.5) years post-injury. All patients had an MRI reviewed by a spine surgeon and neuroradiologist to determine the location of their conus medullaris and precise level of neural axis injury.
Results: Nineteen patients (37%) had SCI, 20 (39%) had CMI, and 12 (24%) had CEI, while two could not be classified. Patients with SCI improved their MS by an average 7.0 motor points (SD 9.8); CMI improved 11.9 (SD 11.8); and CEI improved 16.8 (SD 16.0). This trend did not achieve statistical significance (p=0.09). Multivariate analyses demonstrated that initial MS had a significant interaction with neural axis level of injury with respect to the primary outcome. Specifically, CEI showed the greatest improvement in MS only when the initial MS was less than 75. Absence of initial anal sensation, a fracture-dislocation injury type and increasing time to surgery were all statistically associated with less improvement in MS. The mean follow-up SF-36 physical component score (PCS) was 37.3 (SD 10.1) and the mean mental component score (MCS) was 51.4 (SD 11.8). There was no significant difference in mean PCS and MCS for varying levels of neural axis injury.
Conclusion: Patients with a CEI demonstrated the most improvement in MS, while absent anal sensation, a fracture-dislocation, and long delay to surgery were poor prognostic indicators for motor recovery. The HrQOL outcomes did not vary with neural axis level of injury. The results of this study assist in determining a prognosis for patients that sustain these common injuries. Future research should focus on how specific pre- and peri-operative variables affect outcomes in patients with neurological deficits secondary to thoracolumbar injuries.
