Spondylolisthesis

Spondylolisthesis is a condition in which a vertebral body slips anteriorly in relation to the subjacent vertebrae. The condition affects up to 10% of the population. The two most common forms of spondylolisthesis are isthmic and degenerative. Isthmic spondylolisthesis is associated with a disruption of the vertebral ring and most commonly occurs at L5–S1. This form is most prevalent in children and adolescents and is often associated with repetitive hyperextension of the spine (e.g., in gymnasts). Degenerative spondylolisthesis occurs at L4–L5 and most commonly affects individuals over 50 years of age. Other forms of spondylolisthesis may be associated with congenital disease, trauma or bone fractures, and underlying bone pathology (e.g., Paget disease). Spondylolisthesis may be asymptomatic or cause lumbar pain on exertion, gait problems, radiculopathic pain, or urinary incontinence. Some patients have a palpable step-off sign at the lumbosacral area. Diagnosis is established with imaging. Most patients achieve good symptomatic control with conservative treatment (e.g., physical therapy). Surgical treatment (e.g., vertebral fusion, decompression laminectomy) is reserved for patients with refractory symptoms and/or neurological deficits. Overall, children and adolescents have better outcomes than adults and elderly patients.

• Spondylolisthesis: anterior slippage of a vertebral body over the subjacent vertebra
• Isthmic spondylolisthesis (spondylolytic form): spondylolisthesis resulting from an abnormality in the pars interarticularis ^[1]
• Degenerative spondylolisthesis: spondylolisthesis resulting from degenerative changes, without an associated disruption or defect in the vertebral ring ^[2]
• Congenital spondylolisthesis: spondylolisthesis secondary to congenital anomalies (e.g., hypoplastic facets, sacral deficits, poorly developed pars interarticularis).

• Affects up to 10% of the population
• Most common in children and adolescents < 18 years (congenital and isthmic spondylolisthesis) and adults aged > 50 years (degenerative spondylolisthesis)
• Sex: ♂ > ♀ (congenital and isthmic spondylolisthesis); ♀ > ♂ (degenerative spondylolisthesis)
• Defect most commonly occurs in the lumbar spine (typically L5-S1 in isthmic spondylolisthesis, L4-L5 in degenerative spondylolisthesis) ^[3]

References:^{[1][4][5][6][7][8][9]}

Epidemiological data refers to the US, unless otherwise specified.

Risk factors include:

• Congenital malformation (dysplasia or hypoplasia) of the lumbosacral joints in L5–S1
  • Repetitive hyperextension and rotation movements at L5–S1
  • Commonly associated with gymnastics, swimming, and weight lifting
• Spondylolysis: lytic defect in the pars interarticularis, permitting forward slippage of the superjacent vertebra ; ^[1][10]
  • Leads to isthmic spondylolisthesis if spondylolysis is bilateral
  • Scheuermann disease can be the underlying cause of spondylolysis or spondylolisthesis
• Degenerative disease: most commonly in the elderly at L4–L5
• Trauma
• Local or systemic pathology (e.g., tumor, Paget's disease, osteogenesis imperfecta, TB)

References:^[4]

The severity of symptoms often correlates with the degree of vertebral slippage. ^{[1][2][3][10][11]}

• Asymptomatic (majority of patients) ^[4][11][12]
• Acute or chronic lumbar pain that worsens with activity and/or with spine extension ^[2][3][8]
  • Radiates to the gluteal and posterior thigh regions
  • Often associated with numbness, paresthesias, and muscle weakness ^[1][10]
• Gait problems (e.g., waddling gait, neurogenic claudication)
• Other features of neurological involvement include : ^[2]
  • Radiculopathy
  • Urinary or bowel incontinence
  • Cauda equina syndrome in severe cases
• Possible physical examination findings ^[9][13]
  • Spine
    • Reduced lumbar range of motion and reduced lumbar lordosis
    • Step-off sign (seen in advanced stages)
      • Procedure: Observe and palpate the spinous processes to identify any slippage of the vertebrae.
      • Positive sign: visible or palpable step-off sign at the lumbosacral area ^[9]
  • Lower limbs
    • Tight, contracted hamstring muscles
    • Weakness and atrophy in lower legs; reduced sensation and reflexes
    • Straight leg raise test: A positive test indicates lumbar radiculopathy.

• Consider in patients with characteristic clinical features; in asymptomatic patients, the diagnosis may be incidental.
• Imaging studies confirm the diagnosis, help monitor progression, and are needed to guide the treatment.

Spondylolisthesis is often an incidental finding.

X-ray lumbosacral spine ^[2][8]

• Indications: initial test for all patients in whom spondylolisthesis is suspected
• Views
  • Lateral, PA, and oblique
  • Dynamic flexion-extension (lateral view): Consider performing to assess for spinal instability.
• Supportive findings: anterior vertebral displacement (anterolisthesis) ^[8]
  • L4 over L5: most common in degenerative spondylolisthesis
  • L5 over S1: most common in isthmic spondylolisthesis
• Additional findings
  • Degenerative changes, e.g., disk space narrowing, vacuum phenomenon, endplate sclerosis ^[8]
  • Spondylolysis: in the isthmic form ^[8]
    • Scottie dog with a collar sign ^[8]
    • High-grade spondylolisthesis of L5 over S1 due to bilateral spondylolysis (inverted Napoleon hat sign) ^[3]
  • Spinal instability ^[9]

Additional imaging studies ^[1][2][8]

Order to assess for spinal stenosis and impingement of nerve roots in patients with signs of neurological involvement.

• Indications
  • Clinical features of radiculopathy or myelopathy
  • Suspected underlying condition (e.g., metastatic disease)
  • Suspected cauda equina syndrome (i.e., bladder or bowel complaints)
• Options ^[14][15]
  • First-line: MRI lumbosacral spine ^[1][2][8]
  • Second-line ^[1][2]
    • CT myelography or CT lumbosacral spine
    • For patients with contraindications to MRI; can also be used as a guide to surgical treatment

See also “Differential diagnosis of lower back pain.”

• Facet joint syndrome
  • Irritation of the facet joints, usually due to spondyloarthritis
  • Symptoms can be nonspecific but often include radiating pain to the buttocks or groin
  • It is differentiated from other spinal pathologies (especially discogenic pain) by the fact that pain is not exacerbated with increased intra-abdominal pressure (e.g., Valsalva maneuver)
• Ankylosing spondylitis
• Multiple myeloma
• Spinal disk herniation
• Metastatic bone disease

References:^[4]

The differential diagnoses listed here are not exhaustive.

General principles

• Treatment goals are to reduce pain, restore mobility, and prevent disease progression.
• Conservative treatment can be attempted initially in most patients.
• Surgical treatment is usually reserved for patients with high-grade slippage or persistent symptoms.

Immediate surgery consultation is required for patients with motor deficit or cauda equina syndrome to evaluate the need for emergency surgical decompression. ^[16]

Conservative treatment ^{[2][8][17][18]}

• Indications
  • Initial treatment for patients with low-grade slippage and no significant neurological involvement
  • Consider as initial treatment for high-grade degenerative spondylolisthesis with no significant neurological involvement. ^[8][11]
• General recommendations ^[8][17]
  • Physical therapy: e.g., bracing, back-strengthening exercises ^[8]
  • Physical activity restriction: e.g., 1–2 days of rest during acute symptoms, stopping sports that contribute to spondylolisthesis
  • Management of comorbidities that might contribute to symptoms and disease progression: e.g., osteoporosis or obesity ^[8]
• Pain management
  • First-line: oral analgesics (preferably nonopioid); acetaminophen is the preferred option in elderly patients. ^[8]
  • In patients with persistent symptoms, consider steroid or anesthetic injections (epidural or nerve root) ^[1][2][3]

Surgical treatment ^{[1][2][11][17][18]}

The best surgical approach and indications should be discussed in consultation with a specialist.

• Common indications
  • High-grade spondylolisthesis (Meyerding classification grades ≥ III)
  • Significant neurogenic claudication or radiculopathy
  • Progressive or persistent symptoms (e.g., after 3–6 months) despite conservative treatment
  • Traumatic spondylolisthesis and spinal instability
  • Bladder or bowel symptoms
• Treatment options
  • Vertebral fusion: standard procedure
  • Decompressive laminectomy
    • Consider in addition to vertebral fusion for patients with symptomatic spinal stenosis.
    • Consider as a first-line approach for patients with low-grade degenerative spinal stenosis with symptoms refractory to conservative treatment. ^[2]

• Conservative treatment gives satisfactory results in 80% of cases.
• The rate of success from surgical treatment is higher in children than in adults.

References:^{[19][20][21][22]}