Spondylolisthesis/Spondylolysis

CAUSES — SYMPTOMS — DIAGNOSIS — TREATMENT

Spondylolisthesis is a medical term that refers to a slippage of one vertebral body over another. This most commonly involves the fourth and fifth lumbar or the fifth lumbar and first sacral vertebral bodies. There are a number of reasons for the slip, one of, which is called spondylolysis. Spondylolysis is another name for isthmic spondylolisthesis. In these cases, there is a defect in a portion of the spine called the "pars interarticularis", on x-rays, it is seen as the neck of the "Scotty dog".

Spondylolisthesis is the most common cause of back pain in adolescents but most cases are asymptomatic. Symptoms when they occur often begin with the growth spurt. When symptoms occur, the course can be slow, progressive and severe. Long asymptomatic periods are common.

Spondylolisthesis/Spondylolysis Causes

Spondylolisthesis has a number of causes. Some of the more common are as follows. Isthmic spondylolisthesis (or spondylolysis) commonly caused by fatigue or stress fracture of the pars interarticularis. It may also be a result of an acute (traumatic) fracture. This type is more commonly seen in men and in about half of cases, there will is no slip. This type may be seen on 5 to 20 percent of lumbar spine x-rays.

A second type of spondylolisthesis is congenital spondylolisthesis (also called dysplastic spondylolisthesis). This is more commonly seen in women. Symptoms usually occur during the growth spurt. It accounts for 14 to 21 percent of all spondylolisthesis cases. In these cases there is usually no defect in the pars interarticularis.

A third type of spondylolisthesis is degenerative spondylolisthesis. This type is much more common in women and often occurs after forty years of age. Degenerative spondylolisthesis is usually a result of long-standing instability, most commonly at the junction of the fourth and fifth lumbar vertebrae. The instability is a result of a combination of disc degeneration and facet joint degeneration.

A fourth type of spondylolisthesis is pathologic spondylolisthesis. This may be a result of bone problems such as severe osteoporosis or tumors of the bone (usually metastatic). This is one of the less common causes of spondylolisthesis.

Spondylolisthesis/Spondylolysis Symptoms

The most common symptom of spondylolisthesis is pain. Pain usually begins with the growth spurt of adolescence. This is the most common cause of back pain in the young patient population. The exceptions are the degenerative, traumatic and pathologic types of spondylolisthesis. There are to types of pain seen in cases of spondylolisthesis. One is a sciatic type of pain with radiation (spread) to the buttock, back of the thigh and calf. This is due to stenosis of the lateral recess (the area of the spine where the nerve exits). This type of pain may be mistaken for a lumbar disc herniation. The second pain presentation in spondylolisthesis is claudication type pain. While claudication means limping, the pain is generally related to activity, walking or prolonged standing. The pain in these cases is located in the back, buttocks, thighs or calves. It improves with rest, either sitting or lying down.

Spondylolisthesis/Spondylolysis Diagnosis

As always, a careful history and physical examination are the first steps in diagnosis. The description of the pain is very helpful in diagnosis. There may be sensory loss and or leg weakness. Hamstring tightness is a common finding. Patients with spondylolisthesis may exhibit a type of waddling gait when they walk.

Spondylolisthesis is one of the few spine problems that may be diagnosed with plain lumbar spine x-rays. On the lateral (side view) x-ray, the slip is clearly seen. The degree of slip is classified as grade I if less than 25 percent, grade II if between 25 and 50 percent, grade III if between 50 and 75 percent and grade IV if greater than 75 percent. On certain views, there is an image that looks like a "Scotty dog". In cases of spondylolysis, there will seem to be a fracture across the neck of the Scotty dog. If the fracture line looks old, there is little chance of further slippage. A nuclear medicine bone scan may help to decide the best treatment.

MRI scanning is very helpful in demonstrating the degree of nerve compression. In some cases, lumbar myelogram and post-myelographic CT scanning may be needed to help define the problem. The myelogram and post-myelogram CT scan are particularly helpful in planning surgical treatment.

Spondylolisthesis/Spondylolysis Treatment

The treatment of spondylolisthesis is complex and depends on the presentation (the signs and symptoms). In adolescent cases of isthmic spondylolisthesis (spondylolysis), the x-ray and bone scan may help decide the type of treatment. If the bone scan is positive ("lights up"), a trial of bracing may be successful. Other forms of conservative treatment include rest and physical therapy.

Surgical treatment is divided into two possible approaches, decompression and decompression with fusion. Decompression without fusion is generally avoided as it may lead to further slip and progressive problems. Most surgical procedures include both decompression and fusion. Fusion may be done in situ where no attempt is made to reduce (correct) the slip. In some cases, an attempt may be made to reduce the slip to create a more "normal" appearance to the spine. Frequently, some type of fusion instrumentation will be implanted along with bone graft. The surgeon will decide on the specific type of surgery after taking into account the patients symptoms and the appearance of the various imaging studies.