[Clinico-morphological correlations in uremic osteodystrophy of patients with conservative and hemodialytic treatment with special regard to the ultrastructure].

The results of a histologic and ultrastructural investigation of the skeletal alterations in 2 groups of 50 patients suffering from chronic renal insufficiency are reported. One group was undergoing conservative therapy, the other was dialyzed 3 times/wk. Bone tissue was obtained by iliac crest biopsy. The bone change most frequently encountered in both groups was osteomalacia. This could be associated with hyperparathyroidism, a condition rare in the first group but common in the second. In both groups the bone lesions could be diagnosed correctly by optic microscopy alone. The electron microscope in particular made it possible to obtain information on the degree of calcification which was often deficient despite the normal appearance in the light microscope, and contributed to a more precise assessment of cell function, especially the osteocytes. It was possible to see when osteocyte lacunae were extended as a consequence of osteolysis and when the condition had arisen as a result of defective calcification of the perilacunar osseous matrix. This differentiation is of importance, especially when quantitative determinations have to be made of the degree of osteomalacia and hyperparathyroidism. This is not always easy with the conventional microscope.