Spondylolysis is a defect that can lead to stress fractures in the posterior element of the spine called the pars interarticularis, the thin piece of bone that connects the upper and lower segments of the facet joints. Facet joints link the vertebrae directly above and below to form a working unit that permits movement of the spine.
The term is derived from the Greek words spondylos, which means spine or vertebra, and lysis, which means a break or loosening. If the stress fracture weakens the bone so much that it is unable to maintain its proper position, the vertebra can start to shift out of place, a condition called spondylolisthesis.
Spondylolysis is a common source of lower back pain in adolescents, particularly those involved in athletic activities that place a lot of stress on the lower back or cause constant overstretching (hyperextending) of the spine, such as gymnastics, weightlifting, and football. It is seen more often in males than in females. Spondylolysis is seldom seen in patients under the age of five and is found in 5% of people over the age of seven. It is a common cause of back pain in children, and the most likely cause of back pain in patients under age 26, but rarely the only cause of complaints after age 40.* The defect also may be present in adults with no prior history of injury or sports participation.
The exact cause of spondylolysis is unknown. Some theories point to genetics as a factor, suggesting that those with thinner bones are more susceptible to breakage. Others propose that repetitive trauma to the lower back weakens the pars interarticularis. Spondylolysis also may be associated with conditions that cause instability of the spine, such as lumbar disc degeneration or narrowing of the area where the nerve roots exit the spinal column (the neural foramina).
Many people with spondylolysis may be asymptomatic, meaning they experience no obvious pain or discomfort. Signs the condition may be present include:
- Pain that spreads across the lower back; often feels like muscle strain
- Pain worsens with physical activity, particularly during hyperextension
- Hyperlordosis (increased inward curvature) of the lower back
- Tightening of the hamstring muscles (those in the back of the leg)
- Neurogenic/radiating pain (burning/shooting pain down the leg)
To determine if spondylolysis is the cause of your symptoms, your doctor may, in addition performing a physical exam, recommend a diagnostic test such as an x-ray, computed tomography (CT) scan or magnetic resonance imaging (MRI). The diagnosis of spondylolysis is confirmed by the discovery of a fracture in the pars interarticularis, called a pars defect.
Your doctor will be able to discuss with you what your diagnosis means in terms of treatment options. For most people without any signs of nerve compression or other neurologic impairment, the first line of treatment consists of non-surgical therapies such as medication, rest and physical therapy. Bracing and epidural spinal injections also may be recommended.
Spine surgery is typically considered only after conservative therapies fail to adequately relieve symptoms over a significant period of time, or if evidence of nerve involvement, such as numbness or tingling, muscle weakness or bowel or bladder impairment, develops.
Surgical procedures that may be recommended for the treatment of spondylolysis include:
- Spinal decompression, a procedure in which bone is removed to eliminate nerve pressure
- Spinal fusion, a procedure in which bone graft material is placed between vertebrae to join – or fuse together – the vertebrae to restore spinal stability
The procedures are typically performed together as part of the same surgery, the overall goal of which is to remove the source of irritation and inflammation and restore the stability of the spine.
The benefits of spine surgery, however, must be weighed against the risks. Discuss with your surgeon the risks and benefits of surgery, and the potential results of operative versus non-operative treatment.
* Borenstein DG, Wiesel SW, Boden SD. Low Back Pain: Medical Diagnosis and Comprehensive Management. Philadelphia, PA:W.B. Saunder's Co.;1995.