A model of acute compression spinal cord injury by a mini-invasive expandable balloon in goats

Abstract

To establish a reproducible and manipulable model of acute spinal cord compression injury in large mammals so as to provide a technical and experimental platform for the repair and reconstruction of spinal cord injury (SCI). A total of 15 adult male goats, weighting 35 - 45 kg, were selected. After intravenous anesthesia, a model of acute spinal cord compression injury was established with the balloon of kyphoplasty through mini-open laminotomy. The animals were divided into 4 groups, i.e. 3 in group A and 4 each in groups B, C and D. Goats in group A received mini-open laminotomy without insertion of balloon. In group B, balloons were surgically positioned within the T10-T11 spinal canal but not inflated. The spinal cords of goats in group C were partially compressed by inflating the balloon to approximately 30% of anterior/posterior diameter of vertebral canal. In group D, the balloon was inflated to occupy approximately 90% of canal on a lateral view. X-ray and thin-section computed tomography (CT) scans were used to determine the balloon location. CT scans were also used to calculate the magnitude of balloon inflation and the degree of spinal cord compression within vertebral canal. Improved Tarlov motor function grade test and somatosensory evoked potentials (SSEP) were employed to evaluate the goat neurofunction 24 hours before and 7 days after surgery. Dye volumes of 0, 1.26 ± 0.18 and 2.82 ± 0.20 ml were injected into the balloon to produce spinal occupancies of 0%, 33% ± 2% and 89% ± 4% on X-ray and CT scan. There was a significant dose response for the different levels of injury, with reduced conduction of somatosensory evoked potentials and impaired mobility 7 days after injury. A model of acute spinal cord injury by a tunable compression with a mini-invasive balloon in goats is a useful experiment model of spinal cord injury. It may simulate the clinical situations of acute SCI.