A Modified Weight-Dropping Technique for Experimental Spine and Spinal Cord Injuries

Abstract

Experimental spine and spinal cord injuries were induced in dogs by dropping a 3 kg weight through a guide tube from a two-meter height onto the surgically exposed and stabilized 3rd and 4th cervical spines of sixteen dogs. Skeletal specimens were examined, and the site and extent of fractures were compared with systemic and neurological signs of spinal cord injuries.
Five animals died immediately after injury and another one was found dead the next morning. Out of three survivals that recovered from traumatic shock, two became quadriplegic. Two other animals showed quadriparesis and paraparesis, respectively. Fractures of cervical vertebrae were found in all animals, and their sites occurred in the following frequency: cost-transverse process, spinous process, lamina, vertebral body and pedicle. The 3rd and 4th cervical vertebrae were injured with similar frequency. The fracture characteristics of cervical vertebrae by the present method are briefly discussed.
Every animal with vertebral body fracture either died immediately or developed profound neurological sequelae. Traumatic shock and vertebral body fracture were encountered more frequently in smaller animals, and neurological sequelae were less pronounced in larger animals. Neurological deficits, however, occurred in only one when fractures were limited to the cost-transverse process and spinous process. Only 25% of the animals showed neurological sequelae in the present series. More standardized studies are a prerequisite for the present method to form a reproducible and quantitative injury model of the spine and the spinal cord.