PTH and osteitis fibrosa: Several other prognostic indicators for developing HBS have been proposed across various studies, including biochemical (increased preoperative serum ALP, PTH, calcium, and urea levels), clinical (older age, existence of brown tumors and osteitis fibrosa cystica), parathyroid tumor features (increased weight, atypical, carcinomas) as well as prolonged parathyroidectomy time (157).