Spondylolysis and spondylolisthesis
What are spondylolysis and spondylolisthesis?
The bones of the spine are arranged to give the spinal column stability. Damage or defects within the supporting structures of the lumbar spine can be a source of back pain. A crack in the bony ring of the spinal column is called spondylolysis. If the crack occurs on both sides of the bony ring, the spine is free to slip forward, a condition called spondylolisthesis. About five to six percent of the population is affected by these two conditions.
What causes spondylolysis?
Spondylolysis describes a defect in the bony ring of a vertebra. This type of defect is caused by repeated strain on a bone. At first, the body is able to heal the damage, but if the repeated strains happen faster than the body can respond, the bone eventually fractures. People are not born with spondylolysis, but it commonly appears in childhood. Football linemen and gymnasts are affected the most, and it mainly affects the lowest lumbar vertebra.
What causes spondylolisthesis?
Spondylolisthesis describes a vertebra that has slipped forward on the vertebra below. This usually occurs when a vertebra has a bony defect (spondylosis) on both sides of the bony ring. A crack on both sides of the bony ring separates the facet joints from the back of the spinal column. The facet joints can no longer steady the vertebra. The vertebra on top starts to slide forward, slowly stretching the disc below the damaged vertebra.
In adults, there is usually no danger that the vertebra will slide off the vertebra below. But teenagers sometimes have a unique type of spondylolisthesis in which one vertebra slips forward and slides completely off the vertebra below.
In order to make a proper diagnosis and rule out other possible conditions, the first step is to take a history, including the date of onset, presence or absence of pain, and more.
Your doctor will then perform a physical exam and try to get an understanding of your back problem and how it is affecting you. Your nerves will also be tested by checking your sensation, your reflexes, and the strength of your muscles.
X-rays are often all that is needed to see pars defect or forward slip of a vertebra. A defect on X-ray does not confirm your back symptoms are coming from the defect. X-rays will help your doctor measure any slippage from possible spondylolisthesis.
Other conditions, such as a herniated disc, may be the actual cause of your symptoms. Your doctor will carefully look for all possible causes of your symptoms, which may involve other tests. The most common tests that are ordered are an MRI to look at the nerves and spinal cord; a CT scan to get a better picture of the vertebral bones, and special nerve tests to determine if any nerves are being irritated or pinched.
Spondylolysis and spondylolisthesis can be a source of low back pain. Yet having one of these conditions does not mean you are certain to have back problems. These conditions can cause mechanical pain — the kind that comes from within the moving parts of the spine. They can also cause compressive pain, which is from pressure on the nerves of the low back.
Pinched or irritated nerves produce compressive symptoms. This occurs in spondylolysis when a lump of tissue forms around the crack where the body tries to heal the stress fracture. The lump can cause pressure on the spinal nerves where they leave the spinal canal. A pinched nerve can also happen in spondylolisthesis when the vertebra slides forward and squeezes the nerve. The forward slip of the vertebra also makes the spinal canal smaller, leaving less room for the nerve roots.
Pressure on the nerve can produce pain that radiates down to the foot. It can also cause numbness in the foot and weakness in the muscles supplied by the nerve.
Treatment for spondylolysis and spondylolisthesis is similar to treatments for other causes of mechanical and compressive back pain. Surgery is rarely necessary.
Doctors may prescribe rest, including avoidance of sports activities, to help calm symptoms from mechanical back pain. Special braces, casts, or corsets are used to help heal a stress fracture and to ease the pain.
Your doctor may have you work with a physical therapist. A well-rounded rehabilitation program assists in calming pain and inflammation, improving your mobility and strength, and helping you do your daily activities with greater ease and ability.
Surgery is necessary only if conservative treatments fail to keep your pain at a tolerable level. Surgical treatment for spondylolysis and spondylolisthesis must address the presence of mechanical and compressive symptoms.
Nerve pressure may require surgical decompression, called decompressive laminectomy of the lumbar spine. In order to free up or “decompress” the nerves, the surgeon must remove a section of bone from the back of the spine (lamina). The surgeon may also have to remove a portion of the facet joints. The lamina and facet joints normally provide stability in the spine.
Removal of either or both can cause the spine to become loose and unstable. When this occurs, doctors will include fusion. Likewise, patients needing surgery for spinal instability due to spondylolisthesis typically require lumbar fusion.