Coronal curvature angle and asymmetrical blood vessel distribution in intervertebral discs from aged cadavers: a pilot study.

Abstract

Intervertebral disc degeneration (IVDD) is a major cause of chronic spinal pain and increases with age. Although spinal deformities contribute to asymmetric IVDD, vascular asymmetry within the intervertebral disc (IVD) remains unclear. This study investigated the relationship between differences in vascularity between the concave and convex sides of the IVD and the coronal curvature angle. The study comprised two parts: Study A and Study B. Study A included 15 IVDs (C7-T1, T1-T2, and T7-T8; five discs per level) obtained from five cadavers (two females). Study B included 53 IVDs (C7-T1, n = 8; T1-T2, n = 8; T7-T8, n = 8; L1-L2, n = 11; L3-L4, n = 7; and L4-L5, n = 11) from 11 cadavers (seven females). In total, 68 IVDs from 16 cadavers (mean age 84.6 ± 10.0 years) were analyzed. Coronal curvature angles and disc heights were measured. After coronal sectioning, blood vessels were evaluated using hematoxylin and eosin staining in Study A and CD31 immunohistochemistry in Study B. Disc height was significantly lower on the concave side. In both Study A and Study B, the concave side of the IVD showed increased vascularization. The coronal curvature angle showed a significant association with vascular asymmetry in both studies. Greater coronal curvature angles were associated with increased vascular asymmetry within the IVD. However, because of the observational nature of this study, no causal relationship can be inferred. Further experimental studies are needed.