Causes of Spondylolisthesis
There are five major types of spondylolisthesis, all with different causes. The most common is degeneration of the components of the vertebral column and spine - degenerative spondylolisthesis. These structures, when healthy, maintain the spine’s correct position, allowing for strength and flexibility of movement. As these components degrade, through chronic wear and tear they lose their ability to stay supple and strong, making shifts in the spinal structure more likely, including the slippage of the vertebrae as occurs in spondylolisthesis. Cartilage calcification and degeneration, ligaments stretching and tearing, bone spurs or osteophyte growth, and changes in the shock absorbing and cushioning qualities of the intervertebral discs means that the vertebra can slide forward (or backward in the case of retrolisthesis), and cause deformity of the spine, with associated pain, paraesthesia, pinched nerves, numbness, muscle weakening, and impaired mobility.
Degeneration with age is not, however, the only cause of spondylolisthesis. Congenital abnormalities such as misshapen bones in the spinal column, or problems with the pelvic incidence (tilt), can also cause excess pressure on the spinal column leading to slippage of the vertebrae and spondylolisthesis (Labelle, 2004). This is known as dysplastic spondylolisthesis. Isthmic spondylolisthesis is a further classification, used to describe the condition that results from spondylolysis. This is a condition where repetitive microtrauma causes defects in the pars interarticularis, a specific part of the vertebrae, which may develop into spondylolisthesis if the vertebrae slip forward due to this defect. Spondylolysis is commonly caused in adolescents and children by activities such as gymnastics, football, wrestling, and diving. With appropriate rest and possible use of a brace it should correct itself without developing into spondylolisthesis.
Specific injury or damage to the vertebrae through complications of surgery, epidural injections, assault, or accidents, such as whiplash, can cause traumatic spondylolisthesis. These types of injury can result in fractures of the lamina, facet joints, or pedicle, and allow the vertebrae to slide forward. The final class is pathologic spondylolisthesis. This is where the vertebrae slip forward due to an abnormal growth such as a tumour or bone growth. The specific pathology of the spondylolisthesis requires careful diagnosis in order to apply appropriate treatment.
Last Updated: 10/04/2010