Practice Essentials
Spondylolysis is a defect in the pars interarticularis that may or may not be accompanied by forward translation of one vertebra relative to another (spondylolisthesis).
Kilian, Robert, and Lambl first described spondylolysis accompanied by spondylolisthesis in the literature in the mid-1800s. The number of different spinal abnormalities contributing to development of spondylolisthesis was appreciated only after Naugebauer’s anatomic studies in the late 1800s.
(See the image below.) Radiographic studies allow visualization and grading of spondylolisthesis but may not always reveal the presence of an isolated spondylolysis (without spondylolisthesis). Most patients with low-grade isthmic spondylolisthesis and degenerative spondylolisthesis can be treated conservatively.
Radiograph of the lumbosacral junction showing a grade 1 spondylolytic spondylolisthesis at L5-S1.
Signs and symptoms of spondylolisthesis
Signs and symptoms of isthmic spondylolisthesis include the following
Hamstring tightness is observed almost universally, even in low-grade spondylolisthesis
Lumbar spasm may be present
A palpable step-off is noted with slips equal to or greater than grade 2
With higher degrees of spondylolisthesis, an increased lumbosacral kyphosis is seen (50% or greater), along with a compensatory thoracolumbar lordosis; truncal shortening may be present; with severe slips, the rib cage may rest on the iliac crest
Dermatomal weakness may be present if a radiculopathy or an element of stenosis is present
A waddling gait may be noted secondary to hamstring tightness producing a shortened stride length
If spondylolisthesis is not present, spondylolysis presents with paraspinal spasm, pain provocation with lumbar spine extension, and tight hamstrings
Signs and symptoms of degenerative spondylolisthesis include the following:
These patients present with less prominent physical findings; pain often is provoked with lumbar spine extension
If lumbar stenosis is present, then reflexes may be diminished; radicular findings also may be present
In congenital/dysplastic spondylolisthesis, physical findings are similar to those described above for isthmic spondylolisthesis.
Patients with traumatic and pathologic spondylolisthesis also present with similar findings. A good neurologic evaluation is important.
Workup in spondylosis and spondylolisthesis
Radiologic workup can include the following:
Radiographic studies – These allow visualization and grading of spondylolisthesis but may not always reveal the presence of an isolated spondylolysis (without spondylolisthesis)
Bone scanning – Bone scanning with single-photon emission computed tomography (SPECT) imaging is useful and often helps to direct management
Computed tomography (CT) scanning – This not only documents the presence and severity of spondylolysis but can help to rule out more serious causes for a positive bone scan
Magnetic resonance imaging (MRI) – MRI may visualize edema in the marrow around the sight of an acute spondylolytic defect
Management
The goals of exercise in spondylolisthesis are to improve abdominal strength and increase flexibility. Since tight hamstrings are almost always part of the clinical picture, appropriate hamstring stretching is important. Instruction in pelvic tilt exercises may help to reduce any postural component causing increased lumbar lordosis. Myofascial release may play a role in reducing pain from the surrounding soft tissues.
Surgical treatment is indicated when any type of spondylolisthesis is accompanied by a neurologic deficit. Persistent disabling back pain after conservative management may be considered an indication. High-grade slips (greater than 50%) more commonly require surgical intervention. Traumatic spondylolisthesis is rare but almost always requires surgical stabilization.