Secondary hyperparathyroidism: diagnosis of site of recurrence.

Persistent or recurrent hyperparathyroidism after total parathyroidectomy with forearm implant may be caused by hyperplastic grafted tissue, residual parathyroid tissue left in the neck or the presence of a supernumerary gland not found during surgery. A correct assessment of graft function is needed to localize the source of hormone excess and to avoid an unnecessary neck reoperation in cases of graft dependent hyperparathyroidism. In 12 patients with relapsing hyperparathyroidism after total parathyroidectomy with forearm implant, total ischemic blockade of the arm bearing the parathyroid graft produced a "transitory implantectomy" with a significant reduction of serum levels of intact PTH in those with graft hyperfunction. In 6 patients with proved supernumerary glands, total ischemia of the graft was not followed by significant changes in intact PTH. Hyperparathyroidism was reversed after surgical resection of the parathyroid implants in the 6 patients with positive responses to the ischemic maneuver. A repeat neck reoperation removing cervical or mediastinal supernumerary glands was followed by control of recurrent hyperparathyroidism in the 6 patients with a negative response to the ischemic blockade. Total ischemic blockade of the arm bearing the parathyroid graft is a valuable method for a correct assessment of graft function after total parathyroidectomy with forearm autotransplantation.