Small bones, called vertebrae, align to form the spine in your back. A healthy spine supports the body, while allowing movement. Spondylolisthesis occurs when age or injury causes a vertebra in the lower back to slip forward and out of position.
Spondylolisthesis may not cause symptoms. Spondylolisthesis can cause back or leg pain. The majority of people with symptomatic spondylolisthesis are treated successfully with pain management and restoring function.
Your spine is composed of a series of bones called vertebrae. The lumbar spine forms the curve below your waist in your lower back. Five large vertebrae make up the lumbar spine. A boney arch at the back of the vertebra, called the pars (pars interarticularis), and the facet joints connect the lumbar vertebrae together.
An opening in the center of each vertebra forms the spinal canal. Your spinal cord is located inside the protective spinal canal. Nerves that extend off of the spinal cord travel throughout your body and exchange information with your brain.
Spondylolisthesis results when a vertebra slips out of position in the spine. Degenerated facet joints or a fracture can cause a vertebra to move. With age, the facet joints can deteriorate, weaken and cause one vertebra to slip forward. This condition is called degenerative spondylolisthesis. A stress fracture in the pars on a vertebra (spondylolysis) can lead to isthmic spondylolisthesis, but this is rare occurrence. A vertebra that has moved out of position can press on nerves or narrow the size of the spinal canal (spinal stenosis).
Spondylolisthesis symptoms depend on how far the vertebra has moved out of position and if other structures or nerves are affected. In the vast majority of cases, spondylolisthesis does not cause symptoms. It can cause low back pain and stiffness. Muscle spasms can cause the hamstring muscles at the back of the thighs to tighten. The tightened hamstrings may feel stiff and can affect posture, making it difficult to walk.
A vertebra that has slipped significantly or caused the spinal canal to narrow can press on the spinal nerves. The spinal nerve compression can cause low back and leg pain, leg weakness, lower body numbness or tingling, and reduced or absent leg reflexes.
Prolonged standing or walking may increase your symptoms. Bending forward or sitting may relieve symptoms because these positions increase the room in the spinal canal, taking pressure off the spinal cord.
If the spinal nerves in the lower end of the lumbar spine are compressed, a condition called Cauda Equina Syndrome may result. Cauda Equina Syndrome can cause loss of bladder and bowel control, as well as low back pain, leg pain, leg weakness, lower body sensory deficits, and reduced or absent leg reflexes. If you suspect you have Cauda Equina Syndrome, seek emergency medical treatment immediately.
Your doctor can diagnose spondylolisthesis by reviewing your medical history and examining you. You should tell your doctor about your symptoms. You will be asked to perform simple movements to help your doctor evaluate your muscle strength, joint motion, and spine stability. X-rays are used to view the alignment of your spine. Additional imaging studies may be ordered to identify nerve root compression or spinal canal narrowing.
Spondylolisthesis is graded based on how far the vertebra has moved out of place (slippage). The grade and the severity of symptoms are considered when planning treatment. Spondylolisthesis is graded as follows:
- Grade 1: Less than 25% of slippage
- Grade 2: 25-50% of slippage
- Grade 3: 50-75% of slippage
- Grade 4: Greater than 75% of slippage
- The majority of cases are rated as Grade 1or 2.
Spondylolisthesis that does not cause symptoms does not need treatment. The majority of people with spondylolisthesis are treated without surgery. Treatments to relieve symptoms from Grade 1 and some cases of Grade 2 spondylolisthesis are aimed at pain management and improved function.
Pain relieving and anti-inflammatory medications may be used to ease symptoms. If your symptoms do not improve significantly with these medications, your doctor may recommend epidural steroid injections. Epidural steroid injections are used to place medicine directly near the source of pain and inflammation. Steroid medication is used to reduce inflammation and relieve pain. Epidural injections are short outpatient procedures that may be repeated over time.
Pain relief from medications or epidural spinal injections may allow you to participate in physical therapy. Your physical therapist will teach you exercises to help strengthen your back, abdomen, and legs. Stretching exercises will help to keep your hamstrings flexible and improve posture for standing and walking.
Surgery may be needed for some people with a Grade 2 spondylolisthesis and those with Grade 3 or higher. Again, the overall percentage of people with spondylolisthesis that require surgery is relatively small. Surgery is necessary when the slipped vertebra is unstable, when symptoms are severe, and when nerve compression causes neurological symptoms. Spinal fusion surgery is used to secure the vertebrae together. A lumbar laminectomy surgery is used to enlarge the spinal canal to take pressure off the spinal cord or nerves.
Am I at Risk?
- In rare cases, spondylolysis can precede spondylolisthesis.
- Degenerative spondylolisthesis occurs most frequently in people over the age of 65.
- Women experience spondylolisthesis more often than men do.