My 23-year old son was recently told he has unilateral spondylolysis of the spine. The medical report says it’s “benign.” What does this mean?

Spondylolysis refers to a crack in the vertebral bone. Unilateral means it’s only on one side. Benign suggests the condition won’t get worse or cause further problems. When spondylolysis occurs on both sides of the spine at the same time, the body of the vertebra can slip forward. The slippage can cause a worse problem called spondylolisthesis.

A recent study from the University of Toledo suggests this condition may not be so benign in young active athletes. They looked at 13 athletes younger than age 20. Each one had unilateral spondylolysis.

A computer analysis of the CT scans showed increased bone remodeling on the opposite side of the spondylolysis. There is an increased risk of stress fractures on the other side of the spine. Repeated spinal motions, especially rotation, seem to be the biggest risk factors. Medical follow-up is advised if your son starts having back pain that doesn’t go away.