Significant correlation between cerebrospinal fluid nitric oxide concentrations and neurologic prognosis in incomplete cervical cord injury

In animal models of spinal cord injury (SCI), inducible NO (nitric oxide) synthase is expressed in the spinal cord immediately after sustaining SCI. Excessive NO production has cytotoxic effects and induces neuronal apoptosis, causing neural degeneration and neurodysfunction in the spinal cord. Little is known, however, about the relationship between NO_x (NO metabolites: nitrite and nitrate) levels in the cerebrospinal fluid (CSF) and neurologic severity or recovery in clinical cases. The objective of the present study was to examine the correlation between CSF NO_x levels and neurologic severity or recovery in SCI. Twenty-five patients with incomplete cervical cord injury (CCI) were examined. Eight cases were treated conservatively (non-operated group). Seventeen cases underwent surgical intervention (operated group). NO_x levels in the CSF were measured using the Griess method. The severity of the neurologic impairment was assessed using Frankel’s classification and the American Spinal Injury Association motor score (ASIA MS). The degree of neurologic recovery was assessed using Frankel’s classification and the ASIA motor recovery percentage (MRP). There was no significant difference in the NO_x levels between the CCI group (NO_x levels: 5.9 ± 0.7 μM) and the 36 control subjects (1 volunteer and 35 patients without neurologic disorders, NO_x levels: 4.9 ± 0.3 μM). There was no significant difference in NO_x levels and MRP between the non-operated group and the operated group. The NO_x levels in total SCI group were significantly correlated with the ASIA MS and MRP. There was a significant correlation between CSF NO_x levels and neurologic severity or recovery in incomplete CCI.