These linked conditions generally affect your lower back but may occur in any part of your spine. Spondylolysis occurs when a defect or weakness in a vertebra is then at risk of slipping out of line with the vertebrae adjacent to it, leading to spondylolisthesis, which can be debilitating and painful, or may be painless and go unnoticed.
Spondylolysis may start with a minor crack across the narrow arch of bone in a vertebra, known as the neural arch. In some cases, this crack is present at birth, but usually it is the result of a fall or due to strain and overuse. Some sports, such as cricket and football, repeatedly put stress on the arches of the vertebrae, which can lead to minor cracks or breaks. Spondylisthesis generally develops from spondylolysis, with the crack widening to a complete break due to further stresses and strains. This break allows the damaged vertebra to slip out of line, which can irritate the linked facet joints and ligaments and possibly trap a nerve.
Symptoms and Diagnosis
The pain from a displaced vertebra due to spondylolisthesis depends on the degree of slippage. A slight slip may cause little or no pain, while a greater degree of slippage can lead to more intense pain because of the irritation to the spinal joints and ligaments. If your nerve is trapped, there may be some pain, numbness, or “pins and needles” in one or both of your legs. Your doctor will make a diagnosis is through a physical examination and testing including an X-ray, MRI scan, and myelogram.
Risks and Recovery
Back-strengthening exercises can help stabilise your posture, but where vertebrae have severely slipped, nerve entrapment can develop that may require surgery. Young people diagnosed with spondylolisthesis should avoid contact sports and activities with a high risk of back injury. A young person who is still growing should be monitored every six months, using X-rays to detect further movements and shifts in the spinal column. Once growth stops, the vertebrae are unlikely to slip any further.