Practice Essentials
Spondylolisthesis is defined as forward translation of a vertebral body with respect to the vertebra below. Although spondylolisthesis is often asymptomatic, it is one of the most common underlying causes of persistent low back pain among children and adolescents. [1] Spondylolisthesis can usually be managed with conservative treatment; however, surgery is indicated for patients with high-grade slippage, refractory symptoms, or progressive neurologic deficit.
Signs and symptoms
Spondylolisthesis is typically asymptomatic. The most frequently reported symptom is low back pain, which is often exacerbated by motion, particularly lumbar extension and twisting. Radiation of pain into the buttocks is not uncommon.
See Presentation for more detail.
Diagnosis
Imaging studies
Imaging studies are necessary for an accurate assessment and diagnosis of spondylolisthesis. The studies are typically pursued in the following order:
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Radiography: Standing lateral radiographs are the preferred method of evaluating slippage of the vertebrae.
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Single-photon emission computed tomography (SPECT) scanning: SPECT scanning is an extremely sensitive means of evaluating the integrity of the pars interarticularis.
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Computed tomography (CT) scanning: CT scanning is the best test for defining bony detail.
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Magnetic resonance imaging (MRI): MRI should be ordered in cases that are associated with neurologic deficits.
Other diagnostic tests
If alternative diagnoses are being considered, order appropriate laboratory tests (eg, laboratory workup for malignancy). An electromyogram may be helpful for detecting subtle radiculopathy, especially in the setting of a negative neurologic examination.
See Workup for more detail.
Management
Rehabilitation program
In general, a physical therapy regimen is started after the patient has had an adequate rest period and pain with daily activities has subsided. The regimen consists of exercises to strengthen the abdominal muscles and flexibility programs to stretch the spinal extensor muscles, hamstrings, and lumbodorsal fascia. Avoidance of heavy-duty labor or activities with repetitive lumbar extension is necessary to allow healing to occur. Bracing with a thoracolumbosacral orthosis may offer relief for those who do not respond to activity restrictions or whose daily activities are producing symptoms.
Surgical intervention
Surgery is indicated if the slippage is greater than 50% or in cases with refractory symptoms or progressive neurologic deficits. Options for operative management include direct repair of the spondylolytic defect, fusion in situ, reduction and fusion, and vertebrectomy.
See Treatment for more detail.
Background
Spondylolisthesis is defined as forward translation of a vertebral body with respect to the vertebra below. [2, 3, 4, 5, 6, 7] The term is derived from the Greek roots spondylo, meaning spine, and listhesis, meaning to slide down a slippery path.
Spondylolisthesis can occur at any level of the spinal column, although it is most common in the lower lumbar spine. Most cases are thought to result from minor overuse trauma, particularly repetitive hyperextension of the lumbar spine. Spondylolysis, a break in the vertebra typically in the region of the pars interarticularis, may or may not be associated with a spondylolisthesis. If the pars defect is bilateral, it may allow slippage of the vertebra, typically L5 on S1, resulting in spondylolisthesis.
Both spondylolysis and spondylolisthesis are often asymptomatic, and the degree of spondylolisthesis does not necessarily correlate with the incidence or severity of symptoms, even when a patient is experiencing back pain. However, these 2 entities have been reported to be the most common underlying causes of persistent low back pain among children and adolescents, despite the fact that most cases are asymptomatic. [4, 6, 8, 9, 10]
Spondylolisthesis can be classified into the following 6 distinct categories.
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Type I is congenital (dysplastic) and is caused by agenesis of the superior articular facet.
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Type II, or isthmic (spondylolytic) spondylolisthesis, is caused by pars interarticularis defects.
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Type III, or degenerative spondylolisthesis, is secondary to articular degeneration.
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Type IV, or traumatic spondylolisthesis, is caused by fracture or dislocation of the lumbar spine, not involving the pars.
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Type V is pathologic and is caused by malignancy, infection, or other types of abnormal bone.
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Type VI is postsurgical (iatrogenic).
A computer-assisted classification has been recommended by the Spinal Deformity Study Group based on slip grade, pelvic incidence, and sacro-pelvic and spinal balance. Software enabled observers to identify all 6 types of spondylolisthesis and to identify 7 anatomic landmarks on each radiograph. [11]
A variety of methods are also used to measure the degree of spondylolisthesis. The primary focus of this article is isthmic spondylolisthesis only, because it is the most common variety and because it is relevant to sports medicine.
Isthmic (spondylolytic) spondylolisthesis usually occurs in children older than 5 years, most commonly in those aged 7-8 years, and it rarely occurs before walking begins. Slip progression is minimal after skeletal maturity.
Isthmic spondylolisthesis is further divided into the following 3 subtypes:
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Type IIA, or lytic spondylolisthesis, involves a defect in the pars area and is thought to result from recurrent microfractures from the impact of the articular processes against the pars while in extension. This defect usually occurs by age 6 years and is occasionally associated with developmental anomalies such as lumbarization, sacralization, and spina bifida occulta.
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Type IIB involves an intact but elongated pars, probably resulting from repetitive microfractures that heal in an elongated position, much like pulled toffee.
For helpful patient education resources, see Back Pain, Slipped Disk, and Lumbar Laminectomy.
Etiology
Functional anatomy
Mechanical stresses play an important role in this process. Erect posture produces a constant downward and forward thrust on the lumbar vertebrae. Stresses on the pars interarticularis are accentuated during repetitive hyperextension, which results in increased contact of the caudal edge of the L4 inferior articular facet with the L5 pars interarticularis. This collective trauma may eventually result in a stress fracture of the pars interarticularis. Spondylolisthesis may occur when bilateral pars defects are present, which allows forward slippage of the vertebra (typically L5 on S1). Spondylolisthesis has never been reported in quadrupeds or in people who are chronically bedridden.
Sport-specific biomechanics
Sports that involve repetitive hyperextension and axial loading of the lumbar spine may result in repetitive microtrauma to the pars interarticularis, resulting in spondylolysis and sometimes spondylolisthesis. Examples of such activities include gymnastics, football (lineman), wrestling, weight lifting (particularly standing overhead presses), rowing, pole vaulting, diving, hurdling, swimming (especially the butterfly stroke), baseball (especially pitching), tennis (especially serving), sailing (particularly the hiking maneuver), and volleyball. Gymnastics and football are generally considered the highest risk sports. [5, 6, 7, 12]
Epidemiology
United States data
The prevalence of isthmic spondylolisthesis is approximately 5% at age 5-7 years, with an increase to 6-7% by age 18 years. This condition is twice as common in males as in females, and the prevalence is lower among blacks (2.8%, black men; 1.1%, black women) than among whites (6.4%, white men; 2.3%, white women). Despite the higher prevalence among males, progression, although still rare, has been reported to be more common in females. [13]
Additional risk factors include having a first-degree relative with a slip, occult spina bifida at S1, and the presence of scoliosis.
International data
A study by de Schepper et al described the magnetic resonance imaging (MRI) findings of 683 patients with low back pain who presented for a lumbar MRI examination after they had been referred by their general practitioner (GP). The investigators found that 94% of the participants had abnormal MRI findings, and 18% showed signs of spondylolisthesis. [14]
