What is anterolisthesis?

What is Anterolisthesis?

Anterolisthesis is the forward displacement of one vertebra relative to the vertebra below it, most commonly occurring at the L5-S1 level but also at L4-5. 1, 2

Definition and Mechanism

• Anterolisthesis represents a specific type of spondylolisthesis where the vertebral body slips anteriorly (forward) rather than posteriorly 1, 3
• For this forward slippage to occur, there must be anatomical disruption of the structures that normally resist anterior displacement, including the posterior facets, neural arch, pedicle, or intervertebral disc 2
• The condition is graded from 1-4 based on the severity of vertebral displacement, with grade 1 representing the mildest form 2, 4

Common Types and Locations

• Isthmic anterolisthesis occurs due to a defect in the pars interarticularis (most commonly at L5-S1), and is the most frequently encountered type in clinical practice 2
• Degenerative anterolisthesis results from remodeling of the facet joints, most commonly affecting the L4-5 level in women over age 40 2, 3
• The L5-S1 level is the most common site overall for anterolisthesis 1, 2

Clinical Presentation

• Patients typically experience lower back pain, stiffness, muscle tightness, and neurological symptoms if nerve compression occurs 1
• When associated with spinal stenosis, patients may develop neurogenic claudication or intermittent claudication 3
• Severe cases can cause difficulties with daily activities involving hip movement, altered gait patterns, and challenges maintaining stable posture 1
• Neurological symptoms such as vesicorectal disorders indicate more severe compression requiring urgent evaluation 3

Distinction from Spondylolisthesis

• Anterolisthesis is a directional descriptor within the broader category of spondylolisthesis 1, 3
• While spondylolisthesis can refer to either anterior or posterior displacement, anterolisthesis specifically denotes forward slippage 1
• The term "pseudospondylolisthesis" is sometimes used interchangeably with degenerative spondylolisthesis 3

Clinical Significance for Treatment Decisions

• The presence of anterolisthesis represents spinal instability, which fundamentally changes surgical management recommendations 5, 6
• Patients with stenosis and anterolisthesis require decompression plus fusion, whereas those with stenosis alone may only need decompression 5, 6
• The degree of anterolisthesis (grade) influences surgical planning, with higher grades requiring more aggressive stabilization 7