Bone biopsy in the diagnosis of renal osteodystrophy.

When renal disease develops, mineral and vitamin D homeostasis is disrupted, resulting in diverse manifestations in bone cells and structure as well as the rate of bone turnover. In ESRF when patients require chronic maintenance dialysis, nearly all of them have abnormal bone histology named renal osteodystrophy (ROD). On the other hand, survival rates of patients on dialysis have increased with improved dialytic therapy and the resultant increased duration of dialysis has led to a rise in renal osteodystrophy. Because this metabolic bone disease can produce fractures, bone pain, and deformities late in the course of the disease, prevention and early treatment are essential. Serum PTH levels are commonly used to assess bone turnover in dialyzed patients. However, it is found that serum PTH levels between 65 and 450 pg/ml seen in the majority of dialysis patients are not predictive of the underlying bone disease. To date, bone biopsy is the most powerful and informative diagnostic tool to provide important information on precisely the type of renal osteodystrophy affecting patients, the degree of severity of the lesions, and the presence and amount of aluminum and strontium deposition in bone. Bone biopsy is not only useful in clinical settings but also in research to assess the effects of therapies on bone. Although considered as an invasive procedure, bone biopsy has been proven as safe and free from major complications besides pain, haematoma or wound infections, but the operator's experience and skill is important in minimizing morbidity. Alternatives to bone biopsy continue to be pursued, but the non-invasive bone markers have not been proven to hold sufficient diagnostic performance related to the bone turnover, mineralization process and bone cell abnormality. At present however, the transiliac bone biopsy remains the golden standard in the diagnosis of renal osteodystrophy.