Three-dimensional analysis of the spine in autopsy cases with renal osteodystrophy

The spinal column was removed from nine autopsy cases with chronic maintenance dialysis and sectioned in the sagittal plane to a thickness of 1 millimeter using a surface-stained block grinding technique. A combination of two- and three-dimensional analysis included an evaluation of the spine deformity index (SDI), the bone volume (BV/TV), the trabecular interconnection (TBPf), the trabecular thickness (Tb.Th), the trabecular number (Tb.N) as well as a qualitative investigation of the structure of cancellous bone. The control group consisted of 26 autopsy cases with intact skeletons. An iliac crest biopsy made a direct comparison of the diagnostic biopsy location and the spinal column possible. The SDI showed vertebral fractures in renal osteodystrophy (ROD) of types I and II, in spite of a trabecular bone volume within normal limits. The trabecular bone volume showed mean values and a distribution throughout the spinal column familiar in the skeletally-intact control group. Those cases with a longer history of hemodialysis showed higher BV/TV values regardless of age and sex. A trabecular volume within normal limits did not mean physiological trabecular interconnection. Perforations were commonly observed with ROD. Classical, hidden and tunnelling perforations were distinguished. Microcallus formations were frequently seen in the periphery of vertebrae at rod nodes, rods and plate intersections. Three-dimensional analysis in ROD shows a greater alteration in architecture than can be assumed from the two-dimensional histological sections.