Spondylolysis results when cracks or fractures occur in the pars interarticularis, the portion of the lumbar spine that joins the upper and lower joints together of a single vertebra (individual bone in the spine).

Spondylolysis is the middle of 3 stages of injury to the pars interarticularis, with the first (least serious) being a stress reaction and the third (most serious) being actual slippage of the vertebra(e) or spondylolisthesis.
In the vast majority of children, the pars interarticularis is normal. But certain patients begin to experience abnormal growth and development in the pars interarticularis, usually after age 8.
In patients with spondylolysis, stress reaction or injury may occur with the excessive wear and tear from activities of daily living, sports, or a fall. Gymnastics and heavy weightlifting are particularly culpable aggravators of spondylolysis symptoms.
Certain ethic groups, like Alaskan Indians, are prone to spondylolysis due to a genetic weakness to the bone.

Symptoms

As with any spine condition or deformity, symptoms can vary from patient to patient but generally include the following:

Persistent lower back pain
Stiffness in the back or legs
Hamstring muscle tightness.

Diagnostics

X-ray imaging typically confirms bony abnormality, particular in cases of spondylolysis and spondylolisthesis. However, with a stress reaction, an x-ray may not reveal any abnormality.

Treatment

The goals of treatment include relieving pain, decreasing acute spasm, and restoring spinal flexibility. The prognosis is affected by slippage of one vertebra on another (spondylolisthesis).

Patients with less than 50% slippage tend to fare well through adolescence.
With slippage of 50% or greater, the potential for additional slippage with growth and aging is greater.

Nonoperative Treatment

Most spondylolysis patients will respond well to conservative (nonoperative) medical management. Post-treatment “maintenance” exercises like truncal core muscle strengthening (pilates or yoga) may be prescribed to condition the muscles and minimize reinjury.

Anti-inflammatory drugs
Brace wear
Activity modifications
Physical therapy treatment that incorporates truncal core strengthening exercises (therapist will caution patient on avoiding hyperextension maneuvers and excessive abdominal "crunches”)

Operative Treatment

If the pain, spasm, or slippage increases despite conservative management, then the surgeon may discuss several potential surgical options with the patient:

1) Spinal fusion (for spondylolisthesis)

For a majority of children and adults, fusing the fifth lumbar vertebra to the sacrum (the most common vertebrae involved in adolescents with spondylolisthesis) is the preferred surgical option.
The fusion involves removing the loose bony fragments and placing bone graft that will lead to the 2 vertebrae “fusing together" to prevent any further slippage. Specially designed screws and rods may be needed to hold the vertebrae in place to help the two bones fuse together.
A perforated, hollow cylinder called a “cage” is sometimes required. The “cage” is filled with bone matter and placed in the disc space between the two vertebrae to increase the likelihood of fusion.
Bones may be realigned depending on how much one vertebra has slipped forward on the other. The most important steps are restoring stability and making sure the nerves have no pressure on them.

2) Pars repair

At times the pars fracture can be repaired without fusing 2 vertebrae together. This involves removing any scar material that may have developed in thefracture site of a single vertebra, and stabilizing the 2 sides of the fracture to restore normal anatomy.