What is anterolisthesis of the lumbar spine?

Anterolisthesis of the Lumbar Spine

Anterolisthesis of the lumbar spine is a condition where a vertebra slips forward relative to the vertebra below it, most commonly occurring at the L4-L5 or L5-S1 levels, and can cause back pain, nerve compression symptoms, and functional limitations depending on the severity of slippage. 1

Definition and Anatomy

Anterolisthesis specifically refers to the forward displacement of a vertebra over the one beneath it. This differs from retrolisthesis, which involves backward displacement. The condition is often described by:

• The affected vertebral levels (e.g., L5-S1 anterolisthesis)
• The degree of slippage (graded according to the Meyerding classification)
• Whether it is degenerative, traumatic, congenital, or pathological in origin

Causes

Anterolisthesis can result from several factors:

• Degenerative changes: The most common cause in older adults, resulting from facet joint arthritis and disc degeneration 2
• Trauma: Acute injury causing disruption of stabilizing structures 3, 4
• Congenital abnormalities: Defects in the pars interarticularis or facet joints
• Pathological conditions: Tumors or infections weakening vertebral structures

Clinical Presentation

Patients with lumbar anterolisthesis may present with:

• Lower back pain that worsens with activity and improves with rest
• Radicular symptoms (leg pain, numbness, tingling) if nerve compression occurs
• Neurogenic claudication (pain with walking that improves with sitting)
• Altered gait patterns
• Difficulty with prolonged standing or sitting 1
• In severe cases, cauda equina syndrome (urinary retention, saddle anesthesia)

Diagnosis

MRI is the preferred imaging modality for evaluating lumbar anterolisthesis, particularly in patients with persistent symptoms who may be candidates for surgical intervention 5. MRI provides excellent soft-tissue contrast and can accurately depict:

• The degree of vertebral slippage
• Associated disc degeneration
• Neural compression
• Ligamentous injury

Other imaging modalities include:

• Plain radiographs: Useful for initial assessment and functional evaluation with flexion-extension views to assess stability 5
• CT scan: Provides detailed bony anatomy and can help with surgical planning 5
• CT myelography: Alternative when MRI is contraindicated 5

Management

Treatment depends on the severity of symptoms, degree of slippage, and neurological involvement:

Conservative Management

For mild to moderate cases without significant neurological deficits:

• Physical therapy focusing on core strengthening and lumbar stabilization
• Pain management with NSAIDs and other analgesics
• Activity modification
• Epidural steroid injections for radicular symptoms 2

Surgical Intervention

Surgery may be considered for:

• Persistent pain despite conservative treatment
• Progressive neurological deficits
• High-grade slippage causing significant disability
• Cauda equina syndrome (emergency)

Surgical options include:

• Decompression alone (for cases with predominant radicular symptoms)
• Decompression with fusion (for cases with instability) 2
• Instrumentation with pedicle screws and rods for stabilization 4

Epidemiology

The prevalence of anterolisthesis varies by population:

• More common in older adults due to degenerative changes
• Significantly higher prevalence in African American women (58.3%) compared to white women of similar age 6
• Prevalence increases with age 6

Prognosis

The natural history of anterolisthesis varies:

• Many cases remain stable and can be managed conservatively
• Some progress over time, requiring closer monitoring
• Degenerative anterolisthesis generally has a better prognosis than traumatic or pathological types
• Surgical outcomes are generally favorable with appropriate patient selection

Clinical Pearls and Pitfalls

• Pearl: Flexion-extension radiographs are essential to identify segmental motion, which is important in the surgical management of spondylolisthesis 5
• Pitfall: Many MRI abnormalities can be seen in asymptomatic individuals, so clinical correlation is essential 5
• Pearl: Traumatic anterolisthesis, though seemingly catastrophic, may be relatively stable if the posterior ligamentous complex remains intact 3
• Pitfall: Retrolisthesis, though less common (4% prevalence), may be associated with more significant functional limitations than anterolisthesis 6

Understanding the specific type, cause, and severity of anterolisthesis is crucial for developing an appropriate treatment plan that addresses both symptoms and underlying pathology.