Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Spondylolisthesis

Basics
Description
  • Spondylolisthesis is an abnormal AP translation of 2 vertebral bodies relative to each other.
    • This translation is secondary to a defect in the pars interarticularis (spondylolysis) or the posterior ligamentous-bony restraints.
  • Spondylolisthesis is classified by type (Table 1) and by the severity of the slip (Table 2).
General Prevention
  • No preventive measures except long-term brace wear have been found to be effective in decreasing the progression of spondylolisthesis.
  • Because major progression is rare, brace treatment commonly is not recommended.
Epidemiology
  • Isthmic spondylolisthesis usually begins in childhood, but a slight increase in incidence occurs in adolescence, up to 6% in males.
  • Degenerative spondylolisthesis occurs mainly in older adults.
  • Compared with males, females develop spondylolisthesis more often and develop more pronounced slips at a younger age.
Incidence
  • 5% of the general population has spondylolysis or spondylolisthesis.
  • It does not occur until 5-6 years of age, when the incidence is 3.3%.
Prevalence
  • The prevalence is 0% at birth, 3-4% at 6 years, and 5-6% in adulthood.
  • Spondylolysis occurs most often at L5.
Risk Factors
  • A family history of spondylolisthesis
  • Particular physical activities in adolescence that involve hyperextension of the spine, such as playing the lineman position in football and participating in gymnastics, have been associated with a high incidence of isthmic spondylolisthesis .
Genetics
  • An increased risk is associated with a positive family history.
  • ~1/4 of affected patients have a positive family history of spondylolisthesis.
Etiology
  • The cause of isthmic spondylolisthesis is a stress fracture through a thin portion of the posterior elements (pars interarticularis).
  • The causes of degenerative spondylolisthesis are degeneration and instability of the disc.
Associated Conditions
  • Most people with the condition are otherwise physically normal.
  • However, an increased risk is present if one has a connective-tissue disorder, such as Marfan syndrome, or neuromuscular conditions, such as athetoid cerebral palsy.
Diagnosis
Signs and Symptoms
  • Symptoms often can be insidious, but they may follow a relatively minor injury.
  • Pain localized to the low back and thigh area may be seen in association with sciatica from an L5 radiculopathy.
  • Back or leg pain
  • Gait abnormality
  • Abnormal posture (hyperlordotic)
  • History of trauma: Acute or mild repetitive, often sports-related
Physical Exam
  • Evaluate ambulation and forward bending.
  • Perform a careful neurologic examination, including assessment of rectal sensation and function.
  • Patients may present with a hypolordotic posture.
  • Patients with a severe slip may show L5 radiculopathy.
  • Perform the limited straight-leg-raise test: A patient with spondylolisthesis will have limited lumbar flexion with major hamstring tightness.
Tests
Lab
Perform electromyography and nerve conduction velocities to assess L5 root compression.
Imaging
  • Conventional radiographs, including a spot lateral of L5-S1, allow assessment of the presence and degrees of spondylolisthesis.
    • Oblique views show the pars interarticularis (neck of the Scotty dog) and visualize the pars defect.
    • Flexion and extension views can illustrate stability, particularly for degenerative and iatrogenic slips.
    • Table 1 Classification of Spondylolisthesis
      Class Associated Risk Factors
      Isthmic Family history, gymnastics, football lineman
      Congenital Spina bifida occulta
      Pathologic Metastatic cancer or infection
      Traumatic Often associated with spinal cord injury
      Degenerative Seen in 6th and 7th decades of life at L4-L5 level
      Iatrogenic Removal of posterior restraints at prior surgery
      Table 2 Grade of Spondylolisthesis
      Spondylolisthesis Grade Percentage of Slip
      Grade 0 0
      Grade I <25
      Grade II 25-50
      Grade III 51-75
      Grade IV 76-100
      Grade V Complete displacement
  • When a clear pars defect is not visualized, and early spondylosis is suspected in an adolescent, a technetium bone scan can be used.
    • For this study, a SPECT scan should be ordered.
  • CT can aid in the diagnosis of occult pars interarticularis defects.
  • MRI often is not useful for identifying spondylitic defects, but it can help in assessing the degrees of neural compression and the hydration status of the L4-L5 disc.
  • Use discography or selective blocks to assess whether the L4-L5 disc or the pars defect is a patient’s pain generator.
Pathological Findings
  • The most common finding is a defect in the pars interarticularis that resembles a fibrous union or pseudoarthrosis.
  • The fibrous mass of the pars defect sometimes PINS the L5 nerve root beneath it.
Differential Diagnosis
  • The differential diagnosis of spondylolisthesis is extremely important because the presence of a spondylitic defect is not necessarily the source of a patient’s pain.
  • A common cause of pain in a patient with a spondylolisthesis is an L4-L5 disc herniation.
    • The differential diagnosis of back pain should include tumor, infection, facet arthropathy, stenosis, or degenerative disc disease.
Treatment
General Measures
  • Children and adolescents:
    • Lumbar bracing in lordosis may be used for up to 6 months to relieve pain.
    • Nonoperative treatment: Good to excellent results in up to 91% of patients
    • Once the patient is asymptomatic without the brace, serial radiographs may be evaluated every 1-2 years until skeletal maturity.
    • Patients for whom a 12-month regimen of nonsurgical treatment fails or who have symptomatic high-grade slips may require posterolateral fusions.
  • Adults:
    • Patients with grade 0 and grade I slips can be treated as for simple mechanical back pain.
    • Patients with more severe slips (grade II or higher) require posterior spine fusion and possible nerve root decompression.
    • Reduction of high-grade slips, the need for anterior spinal fusion, and the levels to be fused are all controversial topics.
Activity
  • Patients (any age) with asymptomatic grade 0 and grade I spondylolisthesis have no restrictions.
  • Symptomatic patients (any age): Activity restriction until they regain painless lumbar flexion and rotation
Special Therapy
Physical Therapy
Hamstring stretching and lumbar lordosis may relieve the discomfort in patients with symptomatic grade 0 or grade I spondylolisthesis.
Medication
Medications used for children or adults should be those typically administered for the relief of back pain: An analgesic with or without muscle relaxant.
Surgery
  • For high-grade slips and patients in whom nonoperative therapy fails, posterior spinal fusion is indicated.
  • The most common procedure is a posterolateral 1-level L5-S1 fusion .
  • If reduction of the spondylolisthesis is attempted or an L5 radiculopathy is present, the L5 nerve root should be widely decompressed.
  • The addition of anterior spinal surgery:
    • Is reserved for the more severe grades
    • May increase the chance of fusion
    • May prevent postsurgical progression of the spondylolisthesis
Follow-up
Prognosis
  • Spondylolisthesis slightly predisposes an individual to problems with chronic back pain.
  • Most symptomatic low-grade slips in children and adolescents can be treated nonsurgically and lead to no long-term disability.
Complications
  • Greatly variable
  • If the slip progresses to a high grade, compression of the cauda equina with loss of bowel and bladder function may occur occasionally.
  • Many different reduction techniques have been described, including halo-femoral traction, cast reduction, and open reduction and internal fixation.
    • After reduction, radiculopathy secondary to L5 nerve root dysfunction can occur .
Miscellaneous
Codes
ICD9-CM
  • 738.4 Isthmic spondylolisthesis, degenerative spondylolisthesis
Patient Teaching
  • Educate patients with a high-grade slip about looking for progressive bladder dysfunction.
  • After recovery from a symptomatic episode, new onset of bowel or bladder symptoms may indicate slip progression.
FAQ
Q: Which nerve root is most likely to be affected by a reduction and fusion of a high-grade L5-S1 spondylolisthesis?
A: The L5 nerve root. For this reason, the L5 nerve root should be decompressed carefully before an attempt at reduction. Also, neuromonitoring may be used during the surgical procedure.

Q: What grade slip does a patient with 20% anterior translation of L4 on L5 have?
A: Grade I. (Table 2.)

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