Cerebrospinal fluid concentrations of nitric oxide metabolites in spinal cord injury

Multiple center study to evaluate cerebrospinal fluid (CSF) concentrations of nitric oxide metabolites [NOx] in relation to neurologic severity and prognosis in spinal cord injury (SCI).

To examine whether CSF [NOx] correlates with neurologic severity and recovery in SCI.

Inducible nitric oxide synthase is expressed in rat spinal cord immediately after SCI. Excessive nitric oxide production is cytotoxic, causing neuronal apoptosis with subsequent neurodysfunction in the spinal cord. We previously reported a significant correlation between initial [NOx] after incomplete cervical cord injury (CCI) and neurologic recovery at the final follow-up in 25 cases.

Ninety-six cases (SCI group), including 76 patients with CCI and 20 patients with thoracic cord injury were examined. Mean follow-up period was 11 months. The control group comprised 40 cases (3 healthy volunteers and 37 patients with neither pain nor neurologic disorders). CSF [NOx] were measured using the Griess method. Severity of neurologic impairment was assessed using Frankel's classification and the American Spinal Injury Association motor score (ASIA MS). Degree of neurologic recovery was assessed using Frankel's classification and the ASIA motor recovery percentage.

CSF [NOx] did not differ significantly among the control, CCI, and thoracic cord injury groups at the initial examination. In the CCI group, [NOx] in the Frankel A and B classes were significantly higher than [NOx] in the control group at 5 to 14 days, in the Frankel A and B classes at 0 to 4 days, and in the Frankel C and D classes at 5 to 14 days. Also, in the CCI group at 5 to 14 days, [NOx] correlated significantly with ASIA MS and motor recovery percentage.

There was a significant correlation between CSF [NOx] at the pathologic early subacute stage (approximately 5-14 days) and neurologic severity and recovery in SCI.