What is spondylolisthesis?
Spondylolisthesis (spon-dee-low-lis-thee-sis) is a condition involving spinal instability, meaning the vertebrae in the spine move around more than they should causing them to slip out of normal position. The term “listhesis” means to slip forward and may put pressure on a nerve, which can cause lower back pain or leg pain. Spondylolisthesis usually occurs between the fourth and fifth lumbar vertebra or at the last lumbar vertebra and the sacrum. This is where your spine curves into its most pronounced “S” shape and where the stress is heaviest.
Slippage is measured on a scale from grade 1 slippage (25%) to grade 4 (100%). The more the lower back curves in (swayback or lordosis), the steeper the grade.
Spondylolysis and spondylolisthesis are separate yet connected conditions. Spondylolysis usually comes first, though not always. Spondylolysis is the weakness or stress fracture in one of the facet joints, and this weakness causes the vertebrae to slip out of their normal position, resulting in spondylolisthesis.
Spondylolisthesis is rare – it only occurs in about 4-6% of the adult population. However, there are different types of spondylolisthesis that people can have:
- Congenital spondylolisthesis – occurs when a baby’s spine doesn’t form the way it should before birth, causing risk of slippage later in life.
- Isthmic spondylolisthesis – result of spondylolysis where the crack or fracture weakens the bone.
- Degenerative spondylolisthesis – occurs due to aging.
- Traumatic spondylolisthesis – occurs when an injury causes the vertebrae to slip.
- Pathological spondylolisthesis – occurs when a disease or tumor causes the condition.
- Post-surgical spondylolisthesis – slippage because of spinal surgery.
What causes spondylolisthesis?
Spondylolisthesis is most often caused by spondylolysis. The cause of spondylolysis is not as clearly defined. Most believe it is due to a genetic weakness of the pars interarticularis. Both spondylolysis and spondylolisthesis can be present at birth or occur through injury. Repeated stress fractures caused by hyperextension of the back (as in gymnastic or football) and traumatic fractures are also causes. The most common cause in adults is degenerative arthritis.
What are symptoms of spondylolisthesis?
Some, if not most, people who experience spondylolisthesis do not experience many symptoms, if at all. Low back pain may be present, as well as:
- Muscle spasms in the hamstring.
- Back stiffness
- Difficulty walking or standing for long periods.
- Pain when bending over.
- Numbness, weakness or tingling of the foot.
The amount of pain you have depends on how fast your vertebrae are slipping. If you have very subtle symptoms, you may only feel tightness in your hamstrings or find that you can no longer touch your toes, but not feel any nerve pain.
How is spondylolisthesis diagnosed?
Your healthcare provider will perform a physical exam and inquire about your symptoms. Imaging tests may also be needed to confirm the diagnosis. A spinal X-ray will help determine if a vertebra is out of place and an MRI will see if there is soft tissue damage, such as discs and nerves.
What are spondylolisthesis treatment options?
Your healthcare provider may suggest starting with noninvasive treatments before considering surgery. These nonsurgical options can include:
- Rest
- Medication
- Steroid injections
- Physical therapy
- Bracing
If you have a high-grade spondylolisthesis, experience severe pain, and nonsurgical treatments aren’t effective, surgery may be recommended. Surgical intervention aims to relieve pressure on the irritated nerves, stabilize your spine, and restore function.
One common surgical option is spinal fusion, which helps address both spinal instability and nerve compression. Depending on the location of the affected vertebrae, your surgeon may perform a transforaminal or lateral spine fusion. The procedure typically begins with a laminectomy (spinal decompression) to relieve nerve pressure. Then, the two affected vertebrae are fused together. Over time, these bones heal into one, eliminating abnormal movement and providing long-term stability.