Parathyroid biopsy to facilitate the preservation of functional parathyroid tissue during thyroidectomy

The preservation of viable parathyroid tissue, either by preserving parathyroid glands in situ with an intact blood supply or by autotransplantation, is an integral element of thyroid surgery. There is a general impression that nonviable parathyroid glands can be recognized on the basis of black or purple-black discoloration of the gland. We came to believe that this is not a reliable way to assess the viability of parathyroid glands because we observed that when we excised parathyroid glands (with the intention of reimplanting them) in situations where it was not feasible to preserve their blood supply, they did not become discolored.

To assess the status of the parathyroid blood supply, we performed incisional biopsies of suspected parathyroid glands during 14 consecutive thyroid operations (9 hemithyroidectomies, 1 completion thyroidectomy, 4 total thyroidectomies), and observed the biopsy site for evidence of active bleeding.

Thirty-four of 36 possible parathyroid glands were histologically confirmed. Seventeen bled actively from the biopsy site and were preserved in situ. The other 17 were felt to be nonviable: 5 were severely discolored (black) and either no bleeding or minor venous oozing was seen when they were biopsied; 12 with normal coloration (3 were harvested prior to biopsy), did not bleed actively following an incisional biopsy. Parathyroid glands that were judged to be devascularized were autotransplanted into the sternocleidomastoid muscle.

The absence of discoloration is not a reliable way to determine whether the parathyroid blood supply is intact. Biopsy of the parathyroid glands during thyroid surgery facilitates the identification of devascularized parathyroid glands that can be salvaged with autotransplantation.