Prevalence and motion characteristics of degenerative cervical spondylolisthesis in the symptomatic adult

Abstract

Study design: Retrospective analysis of kinetic magnetic resonance images.

Objective: To define the prevalence of degenerative cervical spondylolisthesis in symptomatic patients and to analyze the motion characteristics and influence on the spinal canal at the affected level.

Summary of background data: When compared with lumbar spondylolisthesis, there are few studies evaluating cervical spondylolisthesis, and the prevalence and motion characteristics of cervical spondylolisthesis are not well defined.

Methods: Four hundred sixty-eight symptomatic patients underwent upright cervical kinetic magnetic resonance images in neutral, flexion, and extension positions. Segmental displacement and intervertebral angles were measured in 3 positions using computer analysis software. Spondylolisthesis was defined as the vertebral displacement more than 2 mm, and graded based on the magnitude into 2 groups at each level: grade 1 (2-3 mm), grade 2 (>3 mm). Instability was defined as segmental translational motion exceeding 3 mm.

Results: Grade 1 and 2 spondylolisthesis at a minimum of 1 level were observed with a prevalence of 16.4% and 3.4% of all patients, respectively. The most affected levels were C4-C5 (6.2%) and C5-C6 (6.0%) followed by C3-C4 (3.6%) and C6-C7 (3.0%). Translational motion was greater in levels with grade 1 as compared with segments without spondylolisthesis, but there was no difference in angular motion between the 3 groups. Translational instability was observed with a prevalence of 16.7% in grade 2, 4.3% in grade 1, and 3.4% in segments without spondylolisthesis. Space available for the cord at the affected level was decreased and spinal cord compression grade was higher in grade 1 and grade 2 as compared with levels without spondylolisthesis.

Conclusion: Cervical spondylolisthesis of at least 2 mm was observed in 20% of patients and was most common at C4-C5 and C5-C6. The presence of spondylolisthesis was associated with increased translational motion and decreased segmental spinal canal diameter.

Level of evidence: N/A.