Primary hyperparathyroidism: assessment of the effects of parathyroidectomy using dual X-ray absorptiometry (DXA), Trabecular Bone Score and DXA-based three-dimensional modeling.

OBJECTIVE: The aim of this study was to evaluate bone microstructure to determine whether curative surgery of PHPT produces changes in BMD, TBS and 3D-DXA parameters, and whether these changes are comparable.

METHODS: We retrospectively studied 85 patients (60 women and 25 men, 60.4 ± 12.5 years) diagnosed with PHPT and undergoing parathyroidectomy. Mean percent changes in BMD (lumbar spine (LS), femoral neck (FN), total hip (TH) and 1/3 radius), TBS and 3D-DXA parameters (trabecular volumetric BMD (vBMD), cortical vBMD, integral vBMD, cortical surface density (sBMD) and cortical thickness at TH) after surgery (12, 24 and/or 36 months) were calculated and compared, and we sought the determinants of these changes.

RESULTS: After parathyroidectomy, BMD presented statistically significant mean increases in LS, FN and TH during the first 3 years after surgery (p<0.001), accompanied by an improvement in all 3D-DXA parameters, but there were no significant changes in 1/3 radius BMD or TBS. Cortical sBMD, trabecular vBMD and integral vBMD reached mean increases of similar magnitude to those of FN and TH BMD. Age and preoperative serum levels of PTH and CTX were significantly associated with percent changes after surgery.

CONCLUSIONS: We found a benefit of parathyroidectomy for bone, with significant percent increases in LS, FN, and TH BMD up to the third year after surgery, and a qualitative benefit for the hip in both its trabecular and cortical compartments and bone strength.