Asian Spine J.  2016 Dec;10(6):1132-1140. 10.4184/asj.2016.10.6.1132.

Analysis of the Relationship between Ligamentum Flavum Thickening and Lumbar Segmental Instability, Disc Degeneration, and Facet Joint Osteoarthritis in Lumbar Spinal Stenosis

• Yoshiiwa T
• Miyazaki M
• Notani N
• Ishihara T
• Kawano M
• Tsumura H

• KMID: 2362193
• DOI: http://doi.org/10.4184/asj.2016.10.6.1132

Abstract

STUDY DESIGN: Cross-sectional study. PURPOSE: To investigate the relationship between ligamentum flavum (LF) thickening and lumbar segmental instability and disc degeneration and facet joint osteoarthritis. OVERVIEW OF LITERATURE: Posterior spinal structures, including LF thickness, play a major role in lumbar spinal canal stenosis pathogenesis. The cause of LF thickening is multifactorial and includes activity level, age, and mechanical stress. LF thickening pathogenesis is unknown.
METHODS
We examined 419 patients who underwent computed tomography (CT) myelography and magnetic resonance imaging after complaints of clinical symptoms. To investigate LF hypertrophy, 57 patients whose lumbar vertebra had normal disc heights at L4-5 were selected to exclude LF buckling as a hypertrophy component. LF thickness, disc space widening angulation in flexion, segmental angulation, presence of a vacuum phenomenon, and lumbar lordosis at T12-S1 were investigated. Disc and facet degeneration were also evaluated. Facet joint orientation was measured via an axial CT scan.
RESULTS
The mean LF thickness in all patients was 4.4±1.0 mm at L4-5. There was a significant correlation between LF thickness and disc degeneration; LF thickness significantly increased with severe disc degeneration and facet joint osteoarthritis. There was a tendency toward increased LF thickness in more sagittalized facet joints than in coronalized facet joints. Logistic regression analysis showed that LF thickening was influenced by segmental angulation and facet joint osteoarthritis. Patient age was associated with LF thickening.
CONCLUSIONS
LF hypertrophy development was associated with segmental instability and severe disc degeneration, severe facet joint osteoarthritis, and a sagittalized facet joint orientation.

Keyword

Disc degeneration; Ligamentum flavum thickness; Lumbar spine; Facet orientation

MeSH Terms

Animals
Constriction, Pathologic
Cross-Sectional Studies
Humans
Hypertrophy
Intervertebral Disc Degeneration*
Ligamentum Flavum*
Logistic Models
Lordosis
Magnetic Resonance Imaging
Myelography
Osteoarthritis*
Spinal Canal
Spinal Stenosis*
Spine
Stress, Mechanical
Tomography, X-Ray Computed
Vacuum
Zygapophyseal Joint*