What is Spondylolisthesis?
Spondylolisthesis occurs when the vertebrae's support system fails and one vertebra slips forward out of alignment and remains out of position.
It most commonly occurs between the fifth lumbar vertebra and the sacrum, and occasionally between the fourth and fifth lumbar vertebrae.
The vertebrae of the spine normally stack one upon the other and are held in position by supporting structures, ligaments, muscles and discs.
The spine is flexible in many directions because of its ability to bend and move without the vertebrae slipping out of position.
There are two common types of spondylolisthesis: isthmic, related to the presence of spondylolysis and occurring in the immature spine, and degenerative spondylolisthesis, occurring in older individuals with degenerative changes, usually at the fourth or fifth lumbar vertebra. Fracture, tumor, and infection are rare causes.
A change in position of the vertebrae may cause irritation to the nerve roots. The irritation can result in pain and weakness. The symptom pattern is similar to lumbar disc disease and sciatica, as both problems can be caused by spondylolisthesis.
Spondylolisthesis can be an asymptomatic incidental finding on x-ray, or it can be symptomatic (painful). Why it becomes painful, at times, has not been established.
How is it diagnosed?
Spondylolisthesis signs and symptoms
- An individual with spondylolisthesis in the spine may note pain in the back, hip, and leg.
- Weakness of the leg, with a sense of dragging the leg or foot, may be present.
- The individual may be noticeably "sway-backed" (lordosis).
- Individuals may not be able to walk normally and stumble or drag their feet.
- Pain is often aggravated with sitting and standing, while relieved with bedrest and bending over (flexion of the back).
- Leaning backward (back extension) increases the pain.
- If the injury is acute, the symptoms may be dramatic in onset.
Physical exam: A complete musculoskeletal and neurological back exam is necessary to rule out any underlying pathology and the involved nerves.
Findings may include decreased sensation and tendon reflexes, with weakness of the lower leg muscles. Palpation of the spine may reveal a "step off" or an abnormal space between two vertebrae. The range-of-motion of the spine is often limited with guarding, and extension of the spine (bending backwards) aggravates the symptoms. The individual may have a waddling gait. The hamstring muscles in the legs are usually "tight" (limited excursion).
Tests: The diagnosis is most often made with lumbar spine films taken in the lateral view.
Oblique views taken from both sides, are used to define the bony defect in the posterior segment of the vertebrae. X-rays are taken with the back flexed and extended to look for slipping with spine motion, which is rare. CT scans and/or MRI will be used to evaluate the disc, spinal cord, nerve roots and the vertebra. If there was a fracture, bone scans can evaluate healing. EMG and nerve conduction studies will be used to check nerve function.
How is Spondylolisthesis treated?
With chronic conditions that cause intermittent symptoms, treatment is geared toward relieving the pain from nerve irritation.
This would include abdominal muscle strengthening to support the spine, education in body mechanics, medication for pain, and use of a support corset or brace.
In cases with progressive nerve damage, surgery may be required. The procedures are directed at stabilizing and supporting the spine (spinal fusion) to prevent further slippage of the vertebrae and removing (debridement) inflamed tissue away from the nerves. Internal fixation is technically difficult surgery, but improves the results. Physical therapy and rehabilitation is extensive in these cases.
What might complicate it?
Progression of the slip, with increased pressure on the nerve and spinal cord may complicate treatment.
Individuals with progressive degenerative changes will continue to have intermittent symptoms. Surgery can be curative, but some individuals may gain only partial or intermittent relief. Individuals who have sustained an acute fracture with minimal slippage may completely recover when the fracture heals.
Degenerative lumbar disc disease, spinal stenosis and inflammatory disease may present with similar symptoms.
Physical therapy, three times a week, for a period of two to four weeks.
Orthopedic surgeon, neurosurgeon, physiatrist, and anesthesiologist.
Last updated 22 June 2011