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Spondylolysis and Spondylolisthesis

  • Definition

    Spondylolysis refers to a defect in a specific part of the facet joint called the pars interarticularis. This defect can cause instability in the vertebra, much like a loose hinge in a door.

    spondylolisthesis is an anterior or posterior slipping or displacement of one vertebra or another.


    A unilateral or bilateral defect of the pars interarticularis without displacement of the vertebra is known as spondylolysis.

    The first introduction of spondylolisthesis is attributed to Herbinaux, a Belgian obstetrician who noted a bony protuberance that hindered delivery. The term spondylolisthesis was coined in 1854 from the Greek "spondylo" meaning vertebra and "olisthesis" meaning slip.

    Over time, with ongoing stresses, the ligaments and muscles that help hold the vertebral body in place may become overworked and stretched. As a result, the entire vertebral body can slide forward, which can cause nerves to be pinched, resulting in pain. This sliding of the vertebral body is called spondylolisthesis. Both spondylolysis and spondylolisthesis can be present at birth or occur through an injury.

    Spondylolisthesis has been classified into five major types:

    1. Dysplastic, in which congenital bony anomalies of the lumbosacral junction allow the slipping, or listhesis, to occur;

    2. Isthmic, the commonest form of spondylolisthesis, in which a lack of normal bony continuity in each pars interarticularis or isthmus, the narrowest part of the neural arch, permits the displacement;

    3. Degenerative, in which the slipping vertebra remains a single bone but has become unstable because of degenerative joint disease of its facet, or zygapophyseal, joints;

    4. Traumatic, in which a fracture through part of the vertebra other than the isthmus, usually caused by severe violence, results in the anterior displacement;

    5. Pathologic, in which the slipping is a sequel of deforming or destructive bone disease affecting the articular facets.


    Spondylolysis occurs in approximately 5 percent of the population in the U.S. and most commonly is caused by a stress fracture of the partes interarticularis, but may also result from an acute fracture. The L-5 level is by far the most common site, but defects may occur at L-4 and, much more rarely, at L-3 or above. Less than half of the patients with spondylolysis will develop spondylolisthesis, usually on L-5 on S-1.


    Isthmic spondylolisthesis and degenerative spondylolisthesis are frequently associated with low back and lower limb pain. Pain may be severe, slight, or entirely absent. It is often well localized in the lumbosacral joint region but may radiate down one or both legs along the course of the sciatic nerves and especially into the distribution of the peroneal nerves. There is often complaint of stiffness of the back, and all of the symptoms become worse with exercise and strain.

    In cases of extensive slipping the torso is shortened, the ribs may rest on the iliac crests, and the abdomen may protrude. In severe cases, the pelvic inclination is decreased and the body is swayed backward.


    Diagnosis is based upon a combination of the clinical history and x-ray findings.


    For cases in which symptoms are trivial, no treatment is indicated other than periodic roentgenographic follow-up in children.

    When moderate symptoms are present, immobilization of the spine in a flexed position - by means of a plaster cast extending from the lower part of the thighs to above the costal margins - will relieve most of the acute pain. The cast should be followed by a back brace. In the milder cases an ambulatory plaster jacket or brace, together with exercises to decrease pelvic tilt and lumbar lordosis may be adequate treatment. The majority of cases of spondylolisthesis can be treated by conservative means of this type.

    In patients whose pain has continued despite conservative treatment and in children with severe or progressive slipping, surgical fusion of the last two lumbar vertebrae to the sacrum is indicated. The functional results after successful fusion are usually satisfactory. In the rare cases with evidence of pressure on the cauda equina, laminectomy may be carried out.


    What is the problem with the back?

    Is it spondylolysis or spondylolisthesis

    What is the probable cause?

    What are the treatment options?

    Will a brace be needed?

    Would exercise help?

    Is surgery indicated, now or later?