Intramedullary Lesion Length has a Negative Effect on Neurological Recovery in Cervical Spinal Cord Injury Patients with AIS Grades A-C

Introduction Experimental spinal cord injury and clinical studies indicate a relationship between MRI lesion length and outcome. In patients with AIS grades A-B, IMLL expands at a rate of 900 µm/hour, culminating in an intramedullary lesion (IML) which measures ~50 mm at 3 days post-injury. We performed a retrospective analysis to measure the effect of IML length on long-term neurological recovery and to determine the significance of intramedullary lesion length (IMLL) in long-term AIS grade conversion in traumatic cervical spine injury (TCSI). Methods Ninety-five adult patients who underwent decompressive surgery for cervical TSCI were included. Post-decompression IML length was measured and long-term AIS grades were recorded. A regression analysis was performed. Results AIS grade was A in 51, B in 26, and C in 18 patients. Mean IML length on postoperative MRI imaging was 72.6 mm. AIS grade conversion was noted in 46 (48.4%) patients. Conversion was noted in 27.5% of AIS grade A, 65.4% of AIS grade B and 83.3% of AIS grade C patients. Timing of decompression (18.2 hours) had no effect on AIS grade conversion, but conversion was significant in older patients, those with higher ASIA motor score, lower injury severity score, shorter IML length and better evidence of decompression on postoperative MRI. Regression analysis indicated a significant relationship between AIS grade conversion and IML length on postoperative MRI (OR 0.953, 95% CI = 0.9313–0.9761, p = 0.001). Conclusions In AIS grades A-C cervical TSCI, post-decompression rostrocaudal IML length was significant predictor of AIS grade conversion and neurological recovery. The timing of decompression did not correlate with recovery of function.