Development of low-turnover bone diseases after parathyroidectomy and autotransplantation

Parathyroidectomy and immediate autotransplantation (PTX-AT) has been shown to decrease bone pain and increase bone mineral density. However, adynamic bone disease (ABD) has been predicted to develop if the serum intact parathyroid hormone (i-PTH) level remains lower than normal for a long period of time. Therefore, we investigated the bone histology of patients whose serum i-PTH levels did not increase over 70 pg/mL for 1 year after PTX-AT. Four chronic hemodialysis patients were investigated. The serum intact osteocalcin (i-OC) level was measured and histomorphometry for cancellous bone was performed 1 year after the operation. Tetracycline hydrochloride was administered in the 12 weeks after PTX-AT. The serum i-PTH levels were 20.5 +/- 15.0 pg/mL and i-OC levels were 19.5 +/- 0.9 ng/mL. Histomorphometric analyses showed the osteoclast surface to be 0.1% in two cases and 0% in the other two cases, the eroded surface was 7.7 +/- 6.1%, and the fibrosis volume and osteoblast surface were 0% in all four cases. Osteoid volume, osteoid surface and osteoid thickness were lower in cases 1-3, but higher in case 4. All tetracycline labelings were in contact with the mineralization front in cases 1 and 3, but some were not in cases 2 and 4. Serum i-PTH and i-OC levels indicated that ABD developed in these four cases. Histomorphometric analyses revealed that ABD developed in case 1, while either ABD or low-turnover osteomalacia developed in cases 2 and 4, and low-turnover osteomalacia was observed in case 3 after PTX-AT. In conclusion, i-PTH should not be maintained at lower levels to avoid low-turnover bone diseases.