eMedicine Specialties > Sports Medicine > Spine

Lumbosacral Spondylolisthesis

Author: Adam E Perrin, MD, FAAFP, Clinical Assistant Professor, Department of Family Medicine, University of Connecticut School of Medicine; Private Practice, Sports and Family Medicine, Credentialed ImPACT Consultant in Acute Concussion Management, Middlesex Health Systems Primary Care, Inc
Coauthor(s): Brian J Shiple, DO, Chief, Director of Primary Care Sport, Department of Family Medicine, Division of Sports Medicine, Clinical Assistant Professor, Crozer-Keystone Health Systems
Contributor Information and Disclosures

Updated: Jun 3, 2008

Introduction

Background

Spondylolisthesis is defined as forward translation of a vertebral body with respect to the vertebra below.^1,2,3,4,5,6 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.^3,5,7,8,9

Spondylolisthesis can be classified into the following 6 distinct categories.

• Type I
  • Congenital (dysplastic)
  • Caused by agenesis of the superior articular facet
• Type II
  • Isthmic (spondylolytic)
  • Caused by pars interarticularis defects
• Type III
  • Degenerative
  • Secondary to articular degeneration
• Type IV
  • Traumatic
  • Caused by fracture or dislocation of the lumbar spine, not involving the pars
• Type V
  • Pathologic
  • Caused by malignancy, infection, or other types of abnormal bone
• Type VI
  • Postsurgical (iatrogenic)

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:

• 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.
• Type IIB involves an intact but elongated pars, probably resulting from repetitive microfractures that heal in an elongated position, much like pulled toffee.
• Type IIC spondylolisthesis, a rare form, results from an acute fracture of the pars interarticularis during significant trauma.

For excellent patient education resources, visit eMedicine's Sports Injury Center and Back, Ribs, Neck, and Head Center. Also, see eMedicine's patient education articles Back Pain, Slipped Disk, and Lumbar Laminectomy.

Frequency

United States

The prevalence rate 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 in blacks (2.8%, black men; 1.1%, black women) than in whites (6.4%, white men; 2.3%, white women). Despite the higher prevalence in males, progression, although still rare, has been reported to be more common in females.

Additional risk factors include having a first-degree relative with a slip, occult spina bifida at S1, and the presence of scoliosis.

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 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.^4,5,6,10

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Clinical

History

Typical findings when obtaining the history from a patient with spondylolisthesis may include the following:

• The patient is usually asymptomatic.
• The onset usually occurs during the growth spurt in late childhood and early adolescence, probably due to increased participation in strenuous sports during this period.
• Spondylolisthesis is an unlikely cause of back pain in adults (especially after age 40 y) with no history of symptoms before age 30 years; usually, another cause is identified (eg, disc, strain).
• Low back pain is the usual symptom reported, and it is often exacerbated by motion, particularly lumbar extension and twisting. Radiation of pain into the buttocks is not uncommon. The patient may report relief of pain with extended periods of rest.
• Rarely, associated leg pain is present in the L5 or S1 distribution as a result of nerve root compression.
• Symptoms are often more severe during the advanced months of pregnancy.

Related Medscape topics:
Resource Center Adolescent Medicine
Specialty Site Pediatrics

Physical

Findings noted during the physical examination may include the following:

• With high-grade slips, a palpable step-off may be felt over the spinous process at the level above the slipped vertebra because the posterior arch of the forward translated vertebra remains in place.
• Tenderness to deep palpation of the spinous process above the slip (typically L4) may be present. This palpation occasionally causes radicular pain.
• A positive one-leg hyperextension test (stork test) indicates a diagnosis of spondylolysis until proven otherwise. 
• Hamstring tightness that is associated with all grades of symptomatic spondylolisthesis (see Grading ) occurs at a rate of 80%. It commonly results in an abnormal gait, typically waddlelike, due to the inability of the patient to flex the hip with the knees extended.
• Paraspinal muscle spasm and tenderness are usually present.
• In advanced cases, a relatively short torso with a low rib cage, high iliac crests, and heart-shaped buttocks are noted.
• Limited forward flexion of the trunk is common with reduced straight-leg raising, which may cause pain but rarely any signs of nerve root tension.
• Postural deformity and a transverse abdominal crease are seen as a result of the pelvis being thrust forward.
• A thorough neurologic evaluation should be performed, including sensation in the sacral region to check for cauda equina compression.
• Weakness in the tibialis anterior muscle (L4 nerve root) is common.

Causes

• Hereditary factors: The prevalence rate is high in first-degree relatives, varying from 19-69%.
• Trauma
  • Stress fracture in the pars interarticularis is thought to result from repetitive microtrauma, particularly hyperextension.
  • Traumatic injuries are often associated with gymnastics, football (particularly linemen), rowing, diving, swimming (butterfly stroke), tennis, wrestling, and weight lifting, which may give rise to new cases appearing in early adulthood.
  • Isthmic spondylolisthesis is unlikely to be a result of acute trauma, although cases of acute pars fracture (type IIC) are reported, albeit rarely.
• Growth
  • Growth has a definite role in spondylolisthesis.
  • Defects do not occur in newborns. The lesion starts appearing in the skeletally immature athlete aged 5 and older.
  • Increased risk of slippage occurs during the adolescent growth spurt, probably due to an increase in the amount and intensity of athletic participation in activities involving repetitive hyperextension.
  • This factor may also explain higher slippage rates and severities in females, by virtue of their earlier growth spurt compared with their male counterparts.

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