Does the Morphology of the Iliolumbar Ligament Affect Lumbosacral Disc Degeneration?

Abstract

STUDY DESIGN: An anatomic study of the iliolumbar ligament was performed in association with lumbosacral disc degeneration. OBJECTIVES: To determine whether the morphology of the iliolumbar ligament contributes to lumbosacral disc degeneration. SUMMARY OF BACKGROUND DATA: There have been few reports concerning the clinical significance of the iliolumbar ligament. METHODS: We dissected 25 male and 27 female cadavers and measured the length and cross-sectional area of the anterior and posterior bands of the iliolumbar ligament. The specimens were classified into three groups based on the grade of L4-L5 and L5-S1 disc degeneration: the L4-L5 disc was more degenerated than the L5-S1 disc (group L), the L4-L5 disc was less degenerated than the L5-S1 disc (group S), and both discs were equally degenerated (group E). The results were statistically compared among the three groups. RESULTS: The length of the posterior bands and the summation of the length of the anterior and posterior bands were significantly shorter in group L than in group S, and the cross-sectional area of the posterior bands and the summation of the cross-sectional area of the anterior and posterior bands were significantly larger in group L than in groups S or E in the male cadaver specimens. CONCLUSION: If the iliolumbar ligaments (especially the posterior band of the ligament) of a male patient are short and have a large cross-sectional area, the lumbosacral junction can be stabilized by the ligaments, with the L5-S1 disc being protected from degeneration. The L4-L5 disc may be prone to degeneration.