Abstract: Background– Primary spinal cord injury (SCI) due to intervertebral disc extrusion (IVDE) is treated by surgical decompression, but no proven treatments exist for secondary SCI. N-acetylcysteine (NAC), a free radical scavenger, may reduce secondary SCI.
Hypothesis– Postoperative administration of NAC results in faster ambulation and reduced secondary SCI, as measured by serum phosphorylated neurofilament (pNF-H) and urinary 15F2t-isoprostane:creatinine (ISO).
Animals– 21 client-owned dogs with thoracolumbar IVDE.
Methods– Randomized, blinded, placebo-controlled trial. Dogs received intravenous NAC or placebo (0.9% saline) over 48 hours postoperatively. Daily neurological examinations were performed. Serum and urine samples were collected before (t0) and after treatment (t48). pNF-H and ISO concentrations were quantified by ELISA and time to ambulation estimated. Outcome measures were compared within and between groups using Wilcoxon matched-pairs signed rank and Mann-Whitney U tests and paired/unpaired t-tests.
Results– pNF-H significantly increased over time in both the NAC [t0: 0.31 (0.00-1.12) ng/mL; t48: 1.67 (0.00-38.23) ng/mL, P=0.01] and placebo group [t0: 0.12 (0.00-13.09) ng/mL; t48: 1.34 (0.00-41.33) ng/mL, P=0.008]. ISO significantly increased in the NAC [t0: 728.1 +/-186.5 pg/mg; t48: 978.6 +/-215.9 pg/mg, P=0.004] but not placebo group [t0: 1103.0 +/-334.1 pg/mg; t48: 1104.0 +/-435.9 pg/mg, P=0.69]. No significant differences in pNF-H (P=0.96) or ISO concentrations (P=0.41) were found between groups at t48. Mean time to ambulation was not significantly different between groups [NAC: 15.6 +/-12.2 days; placebo: 9.5 +/-7.6 days, P=0.31]. No adverse reactions were observed.
Conclusions and clinical importance– While well tolerated, NAC did not significantly reduce time to ambulation or secondary SCI.
