Comparison of disc and body volumes in degenerated and nondegenerated lumbar discs: a stereological study

Aim: To carry out comparison and correlation analyses of the intervertebral disc (IVD) and vertebral body (VB) volumes in magnetic resonance (MR) images of patients with degenerated and nondegenerated lumbar discs. Materials and methods: MR images were examined retrospectively in 93 patients. Lumbar VB and IVD volumes in T1–T2 weighted sagittal MR images were calculated via the Cavalieri method, a stereological method. Volumetric changes in degenerated and nondegenerated discs were compared. Results: The percentages of degenerated IVDs were 12.9%, 12.9%, 28%, 50.5%, and 52% in discs from levels L1 to L5, respectively. There were no differences in VB volumes between the degenerated and nondegenerated groups for all lumbar vertebra levels. However, significant volumetric decreases were observed in degenerated IVDs for all lumbar vertebra levels, as compared to nondegenerated IVDs. Comparisons of VB volume and IVD volume ratios also revealed decreases, but they were significant only for levels L1 and L4. Conclusion: Disc volumes were found to be decreased, although vertebral bodies were not affected in degenerated IVD groups. However, using VB and IVD volume ratios may not always yield reliable results.