The role of bone biopsy in the management of patients with renal osteodystrophy.

Renal osteodystrophy is not a uniform disease. Therefore, knowledge of the underlying bone abnormalities is essential in deciding specific therapeutic regimens. To date, however, there is no unequivocal noninvasive means with which to define bone abnormalities accurately. The best tool remains mineralized bone histology requiring bone biopsies. Despite recent technical improvements, this technique is underused because of perceived constraints. This article outlines the procedures necessary for increasing the value of bone biopsies, such as tetracycline labeling, and various biopsy techniques and their potential complications. Bone biopsies provide important information on precisely the type of renal bone disease affecting patients: (1) predominant hyperparathyroid bone disease; (2) low-turnover uremic osteodystrophy, encompassing osteomalacic and adynamic renal bone disease; and (3) mixed uremic osteodystrophy, consisting of mild to moderate hyperparathyroid bone disease and defective mineralization. Also, the degree of the severity of the lesions may be assessed. Finally, the presence and quantity of aluminum deposition in bone can be demonstrated. The determination of aluminum overload is needed before the initiation of any therapeutic regimens because it is well known that potentially serious complications can occur with current treatments such as vitamin D therapies, desferoxamine administration, or parathyroidectomy.