Introduction: Spinal cord injury (SCI) leads to permanent disability and has been observed more frequently in warfighters after introduction of more survivable vehicles (MRAP). Rodent research has led to many advances in SCI treatment, but successful clinical translation remains limited. This may be due to species differences, which could be mitigated in large animal models. Several large animal models have been developed - none for ventral SCI - that generate SCI by dorsal weight-drop, compression, or transection. Furthermore, only weight-drop can replicate the blunt injury seen in acute trauma (i.e. burst fracture and fracture-dislocation). However, weight-drop is imprecise and does not accurately reproduce the conditions in such injuries. Therefore, we developed a large animal model of blunt acute traumatic SCI using a custom designed controlled spinal cord impactor.
Methods: Ten female Yucatan miniature swine were utilized for this study. Ventral SCI was produced by creating a 1.5-cm defect in the L1 vertebral body via midline laparotomy and retroperitoneal approach. A custom controlled spinal cord impactor was then introduced and impacts were delivered from 10 to 40 N. Neurological function was assessed for seven days after injury using the Porcine Thoracic Injury Behavioral Scale (PTIBS) and Porcine Neuro-Motor Scale (PNM). Magnetic resonance imaging (MRI) and histology were performed on postoperative day one and seven respectively.
Results: MRI and histology demonstrated correlation between volume and severity of spinal cord injury and the impact force. Furthermore, both the PTIBS and PNM scales correlated with the target impact force.
Conclusions: This novel large animal model and custom spinal cord impactor can reliably produce a gradient of ventral blunt SCI. This could prove to be a valuable tool to investigate SCI seen in burst fracture and other traumatic injuries, and may represent a useful intermediate step in evaluation of SCI treatments.
Patient Care: This model will be used in future studies to assess the physiology and treatment strategies for ventral spinal cord injury.
Learning Objectives: 1. There are no large animal models of ventral spinal cord injury.
2. This new model can reliably produce a gradient of spinal cord injury and will be useful in future studies.