Acute spinal cord injuries are commonly associated with spinal fracture or luxation. Common causes in dogs and cats are automobile accidents, bite wounds, and gunshot wounds. Falls are common causes in horses. Cattle are susceptible to injuries associated with breeding. Pathological fractures are common in cattle, sheep, and pigs with malnutrition or vertebral osteomyelitis.
Damage to the spinal cord is caused not only by the primary mechanical injury but also as a result of edema, hemorrhage, demyelination, and necrosis. Secondary pathological changes occur due to biochemical factors, including the release of free radicals, leukotrienes, and prostaglandins, that cause further injury to nervous tissue and compromise blood flow to the spinal cord.
Clinical signs of spinal trauma are typically acute and can progress in instances of unstable fractures or luxations. Severe thoracolumbar spinal cord injury can cause paraplegia with increased extensor tone in the thoracic limbs (Schiff-Sherrington phenomenon).
Radiographs usually demonstrate vertebral fractures and luxations (see radiographs of fracture and luxation in a dog, and surgery). However, in a study in dogs with acute spinal trauma, radiography was found to have limited sensitivity for detecting vertebral fractures (72%) and subluxations (77%), compared with CT (1); therefore, advanced imaging is indicated in animals with suspected spinal trauma and normal or equivocal radiographic findings.
Lateral radiographic view of a dog with L5-L6 luxation and a fracture of the L5 vertebral body with ventral displacement of the caudal segment.
Courtesy of Dr. William Thomas.
Postoperative lateral radiographic view of a dog with a fracture of the L5 vertebral body and fixation of L5-L6 luxation. Two fully threaded pins each were placed in the vertebral bodies of L4 and L6. Polymethyl methacrylate was used to connect the four pins. The fracture and luxation are well reduced and healing normally.
Courtesy of Dr. William Thomas.
Animals with mild neurological deficits often recover with 4–6 weeks of cage or stall rest and analgesics. Surgical reduction and stabilization is indicated for unstable vertebral injuries causing severe neurological dysfunction.
The prognosis is guarded for recumbent horses and cattle. In animals that have lost deep pain perception caudal to the lesion, the prognosis for return of neurological function is poor.
References
Kinns J, Mai W, Seiler G, et al. Radiographic sensitivity and negative predictive value for acute canine spinal trauma. Vet Radiol Ultrasound. 2006;47(6):563-570. doi:10.1111/j.1740-8261.2006.00186.x
