Animal Models of Orthopedic Research: A Spinal Fusion Model / 대한정형외과학회잡지

ABSTRACT

The incidence of spinal fusion surgery has increased due to an increase in the incidence of degenerative spinal disease or trauma. Moreover, the development of various kinds of implants and bone graft substitutes has also increased. The animal models of spinal fusion are useful methods in evaluating the effectiveness of the newly developed spinal implants or bone graft substitutes. The most widely used animal models of spinal fusion are posterolateral fusion model, posterior fusion model, and anterior interbody fusion model. Mice, rats, rabbits, dogs, pigs, goats, sheep, and primates are frequently used in animal models of spinal fusion. Small animals are implanted with a bone graft substitute without internal fixation; however middle- or large-sized animals are implanted with a bone graft substitute using pedicle screws or cages. Small animals are easy to handle due to their size, but have different anatomical or biomechanical reactions with the human body. Middle- or large-sized animals have characteristics like the human body, but they are difficult to handle or there is an ethical problem. The fusion status is evaluated by manual palpation, mechanical testing using Instron, and radiologic techniques such as computed tomography, micro-computed tomography or undecalcified histology. The fusion rate and duration required for successful fusion differ according to the species and anatomical site. We have identified and reviewed several typical animal models of spinal fusion.