Spondylolisthesis (spon-dee-low-lis-THEE-sis) means one vertebra has slipped forward on the bone below it. The slip is graded from mild (Grade I) to severe. Two common types:
- Isthmic: from a small stress fracture in a thin bridge of bone, often starting in youth from back-arching sports (gymnastics, football, diving, weightlifting). Usually at the bottom of the lumbar spine.
- Degenerative: from age-related wear of the discs and joints letting a vertebra gradually slide forward. Most common after 50, more often in women, usually at L4–L5.
Symptoms
Many people have a slip and no symptoms at all. When present: lower back pain, and often leg pain, numbness, or a pinched-nerve feeling. The degenerative type often causes stenosis-type symptoms (leg pain with walking, relieved by sitting).
How it's diagnosed
X-rays show the slip; "bending" X-rays reveal whether it's unstable. CT can show the bone fracture, and MRI shows whether nerves are pinched.
Treatment
Most people are treated without surgery — physical therapy (core and back strengthening), medicines, activity changes, sometimes bracing, and injections for leg pain. Surgery is considered for symptoms that don't improve, significant nerve compression, or progressive weakness, and usually involves decompression and often fusion to stabilize the slipped bones. Some patients with a small, stable slip do well with decompression alone.
You have loss of bladder or bowel control, saddle numbness, or rapidly worsening leg weakness.