Protective Effect of Extended Laminectomy on Spinal Cord Injury Induced by Spinal Shortening

This study investigates the effect of extended laminectomy (EL) on spinal cord injury (SCI) caused by spinal shortening, and further, the timing and the optimal length of removal. Dogs received spinal column shortening at T13 segment, following which the control group underwent regular laminectomy while other groups underwent laminectomy with an additional 1-lamina length removed 6h after shortening ("1-lamina EL 6 h"), an extra 1.5-lamina length resected at 6 h or 12 h after shortening ("1.5-lamina EL 6 h" and "1.5-lamina EL 12 h"), and an extra 2-lamina length removed at 6 or 12 h after shortening ("2-lamina EL 6 h" and 2-lamina EL 12 h"), respectively. Somatosensory evoked potential (SSEP) and neurological function were recorded periodically; spinal cord blood flow (SCBF) and nerve cell apoptosis were detected. The results showed that resection of an additional 1-lamina length appeared inadequate to relieve the sharp kinking of the spinal cord, whereas the kinking disappeared with an additional 2-lamina length resection. The "1-lamina EL 6 h" and "1.5-lamina EL 12 h" groups showed no significant differences from the control in latency of SSEP, SCBF, hindlimb function and apoptosis. By contrast, significant recovery of SSEP, SCBF and hindlimb function as well as reduction of apoptosis were presented in other three groups. The "2-lamina EL 6 h" group, in particular, showed the most prominent recovery. In conclusion, an additional resection of two laminae at 6 h after shortening showed the best effect in alleviating SCI. Timely and adequately extended laminectomy could be a potential therapeutic strategy for SCI attributable to spinal shortening.