The more common types of spondylolisthesis include:
- Congenital spondylolisthesis– Present at birth, congenital spondylolisthesis is the result of abnormal bone formation. This abnormal arrangement of the vertebrae puts them at greater risk for slipping.
- Isthmic spondylolisthesis – This occurs as the result of spondylolysis, a condition that leads to small stress fractures (breaks) in the vertebrae that weaken the bone so much that it slips out of place.
- Degenerative spondylolisthesis – This is the most common form of spondylolisthesis, and it is caused when aging disks (the cushions between the vertebral bones) loose water and become less spongy and flexible.
Less common forms of spondylolisthesis include:
- Traumatic spondylolisthesis – Caused when an injury leads to a spinal fracture or slippage
- Pathological spondylolisthesis – Occurs when the spine is weakened by disease such as osteoporosis, infection or tumor
- Postsurgical spondylolisthesis – Slippage that occurs or becomes worse after spinal surgery
How common is spondylolisthesis?
Spondylolisthesis is the most common cause of back pain in teens, who often begin showing symptoms during the teenage growth spurt. Degenerative spondylolisthesis occurs most often after age 40.
Symptoms of spondylolisthesis
Oftentimes, people with spondylolisthesis are asymptomatic and don’t even know they have the condition. When symptoms do occur, the most common one is low back pain, which often spreads across the lower back and might feel like a muscle strain.
Spondylolisthesis can also cause muscle spasms in the hamstring muscles in the back of the thighs. Tight hamstrings can cause a person to walk with short strides and with the knees slightly bent. If the slipped vertebra is pressing on a nerve, pain might spread down the leg to the foot. The foot might also tingle or feel numb.
How is spondylolisthesis graded?
By viewing the results of specialized X-rays, a radiologist is able to determine the degree of slippage. Slippage is graded I through IV:
- Grade I – 1 percent to 25 percent slip
- Grade II – 26 percent to 50 percent slip
- Grade III – 51 percent to 75 percent slip
- Grade IV – 76 percent to 100 percent slip
Generally, Grade I and Grade II slippage do not require surgical intervention and are treated medically. Grade III and Grade IV slippage might require surgery if the patient experiences persistent pain or discomfort.
An X-ray of the lower back can show a vertebra out of place. However, your physician may need the more detailed images of computed tomography (CT) or magnetic resonance imaging (MRI) scans to more clearly see the bones and nerves involved.
Treatment for spondylolisthesis depends on several factors, including the age and overall health of the person, the extent of the slippage, and the severity of the symptoms. Most often, treatment is conservative (see below). More severe spondylolisthesis might require surgery.
- Conservative treatment – This involves rest, medication and moderate exercise. We recommend taking a break from sports and other activities until the pain subsides. An over-the-counter nonsteroidal anti-inflammatory drug might help reduce pain and inflammation. If that does not provide relief, your doctor may prescribe stronger medications. Epidural steroid injections, in which medication is placed directly in the space surrounding the spine, might also help reduce inflammation and ease pain.Additionally, we may recommend a brace or back support to help stabilize the lower back and reduce pain. An exercise program or physical therapy will help increase pain-free movement and improve flexibility and muscle strength. We periodically take X-rays to determine if the bone slippage persists.
- Physical therapy – Exercise strengthens the abdominal and back muscles, thus minimizing movement of the spine. We generally recommend eight to 12 weeks of aggressive daily stabilization exercises to achieve clinical improvement.
- Surgery – If the vertebra continues to slip or the pain is not relieved with conservative treatment, surgery may be necessary. With surgery, your doctor is able to stabilize the spine where the vertebra has slipped out of place and relieve the pain associated with an irritated nerve, all of which increases a person’s ability to function.
Two surgical procedures are used to treat spondylolisthesis:
- Decompressive laminectomy – This procedure involves removing the part of the bone that is pressing on the nerves. Although it can reduce pain, removing a piece of bone can leave the spine unstable.
- Spinal fusion – To provide stability to the spine, a piece of bone is transplanted to the back of the spine. As the bone heals, it fuses with the spine and creates a solid mass of bone. This keeps the spine from moving. In some cases, instruments such as rods or screws are used to hold the vertebra firm as the fusion heals.
What are the complications associated with spondylolisthesis?
The persistent pain cause by spondylolisthesis often leads to inactivity, which can result in weight gain as well as loss of bone density and muscle strength. Permanent nerve damage can occur if a slipped vertebra is pressing on a spinal nerve root.
What is the outlook for people with spondylolisthesis?
The outlook depends on the severity of the spondylolisthesis. In the case of minor slippage, where the bone is not pressing on any nerves, the person might never have a recurrence of back pain related to spondylolisthesis.
Conservative treatment for mild cases of spondylolisthesis is successful in about 80 percent of cases. Surgery is successful in relieving symptoms in 85 percent to 90 percent of people with severe spondylolisthesis.
Can spondylolisthesis be prevented?
While not entirely preventable, here are some steps you can take to reduce the risk:
- Maintain a healthy weight. Excess weight puts added stress on your lower back.
- Keep your back and abdominal muscles strong to help support and stabilize the lower back.
- Choose activities and sports that do not place your lower back at risk for injury.
- Keep your bones well-nourished and strong by eating a well-balanced diet.