Spondylolysis and spondylolisthesis

Spondylolysis usually affects the lowest lumbar vertebra or the bones in the lower part of the back. The ring is made up of the pedicle and lamina bones. It's called the pars interacticularis or "pars" for short. The pars protects the spinal cord and nerves.

A pars defect is usually caused by a stress fracture or break. Fractures happen when there is repeated strain on a bone. At first, your body can heal from the damage. But after repeated strains, the bone will break.

People aren't born with spondylolysis. It usually first appears in childhood. Football linemen and gymnasts are affected the most.

When cracks occur on both sides of the bony ring, the diagnosis is spondylolisthesis, and the bone can slip completely out of place. In adults, there is usually no danger of this happening. But in teenagers, this is more likely. 

Spondylolysis and spondylolisthesis can cause lower back pain. Having one of these conditions doesn’t necessarily mean you’ll have low back pain, but it does increase your chances of it.  

Some of the problems you are more likely to have include:

• Mechanical pain or pain when you move your spine
• Compressive pain or pain when tissue that forms around bone cracks and puts pressure on the spinal nerves
• Pinched nerves when the vertebra moves forward and squeezes the nerve 
• Numbness from nerve pressure and weakness in muscles in the affected parts of the body