What is Anterolisthesis
Anterolisthesis is a spinal condition where one vertebra slips forward relative to the vertebra directly below it, most commonly occurring in the lumbar spine at L4-L5 or L5-S1 levels. 1
Definition and Mechanism
Anterolisthesis represents anterior displacement of a vertebral body over the adjacent inferior vertebra. 1 This forward slippage can result from:
- Degenerative changes in the spine, including disc degeneration, facet joint arthropathy, and ligamentous laxity 2
- Traumatic injury, such as pedicle avulsion or posterior element disruption 3
- Congenital abnormalities affecting spinal stability 1
The condition differs fundamentally from retrolisthesis (posterior slippage), with distinct pathomechanisms—anterolisthesis relates to increased pedicle-facet angle and W-shaped facet joints, while retrolisthesis has different biomechanical factors. 4
Clinical Presentation
Patients with anterolisthesis commonly experience:
- Lower back pain with or without radicular symptoms 1, 2
- Neurogenic claudication when associated with spinal stenosis 5
- Stiffness and muscle tightness in the lumbar region 1
- Neurological symptoms including leg pain, numbness, or weakness if nerve compression occurs 1, 2
- Altered gait patterns and difficulty maintaining stable posture during prolonged standing or walking 1
Epidemiology and Risk Factors
The prevalence varies significantly by population:
- African American women aged ≥65 years show remarkably high prevalence (58.3% overall), with 36.5% at L4-L5 and 29.6% at L5-S1 6
- White women of similar age demonstrate 2-3 times lower prevalence 6
- Female predominance exists, particularly at L4 level 4
- Age-related increase in prevalence, though lower rates occur in women with oophorectomy or estrogen replacement therapy 6
Importantly, anterolisthesis presence does not necessarily correlate with back dysfunction or decreased physical function in community-dwelling older adults. 6
Grading and Severity
Anterolisthesis is graded based on the degree of forward slippage:
- Grade 1: <25% slip
- Grade 2: 25-50% slip
- Grade 3: 50-75% slip
- Grade 4: >75% slip 3
Clinically significant anterolisthesis is typically defined as ≥3mm of subluxation on lateral radiographs. 6
Multilevel Involvement
Multilevel degenerative spondylolisthesis occurs in approximately 34% of affected patients (69 of 201), with 94% involving two segments. 4 Patterns include:
- Anterolisthesis only (21 cases)
- Retrolisthesis only (25 cases)
- Combined anterior and posterior slippage at different levels (19 cases) 4
Traumatic multilevel anterolisthesis (e.g., L3,4,5 over S1) can occur from pedicle avulsion injuries, though this represents an unusual pattern requiring surgical stabilization. 3
Management Implications
Conservative management should be the initial approach for most cases of degenerative anterolisthesis, with or without neurological symptoms. 2 Treatment options include:
- Analgesics and NSAIDs for pain control 2
- Epidural steroid injections for radicular symptoms 2
- Physical therapy focusing on flexion strengthening exercises and core stabilization 1, 2
- Bracing for symptomatic relief 2
Surgical intervention with decompression and fusion is recommended when patients have symptomatic stenosis associated with spondylolisthesis and have failed conservative management (Grade B recommendation). 5 The presence of anterolisthesis with stenosis represents documented instability warranting fusion to prevent progression and optimize outcomes. 5, 7
Prognosis
The natural history is generally favorable for patients without neurological symptoms. 2 However, patients with neurogenic claudication or vesicorectal dysfunction will likely experience neurological deterioration without surgical intervention. 2 Interestingly, the mere radiographic presence of anterolisthesis in older adults does not predict back problems or functional limitations. 6