Changes in bone mineral density after total parathyroidectomy without autotransplantation in the end-stage renal disease patients with secondary hyperparathyroidism

Background: The patients with secondary hyperparathyroidism (SHPT) usually had reduced bone mineral density, which might lead to a substantial increase in osteoporosis, fracture and mortality. Although surgical intervention is effective in reducing parathyroid hormone (PTH) levels in suitable candidates refractory to medical therapy, the effect of surgery on bone mass changes still requires further evaluation. Thus, the aim of this study was to evaluate the characteristics of BMD changes after total parathyroidectomy (PTX) without autotransplantation and its associated factors. Methods: The records of 34 patients who underwent successful total PTX without autotransplantation with a preoperative and postoperative dual energy X-ray absorptiometry (DEXA) scan in our institution within 4 years of operative intervention were reviewed. Correlation and regression analysis were used to identify factors that independently predict BMD changes. Results: At baseline, we found that the prevalence of osteoporosis seemed to be much higher in the load-bearing lumbar spine than in the hip, varying greatly even between different lumbar vertebrae. The bone loss in SHPT had its predilection site in the load-bearing cancellous bone. After curative total PTX without autotransplantation, BMD improved significantly in both lumbar spine and hip overall. The largest increase in BMD occurred at L4 vertebrae with the lowest pre-operative BMD. At the most affected site L4, BMD improved in up to 94.1% of patients: 86.2% had significant improvement, 5.9% moderate improvement, and 5.9% declining bone mineral density. Correlation and regression analysis suggested that percentage changes in BMD were predicted negatively by the preoperative BMD and positively by the preoperative parathyroid mass but not intact PTH levels. Conclusion: Total parathyroidectomy without autotransplantation could improve BMD of secondary hyperparathyroidism at L1-L4 and the hip. Furthermore, the large parathyroid glandular mass and the preoperative BMD predicted the BMD changes after surgery.