Parathyroid transplantation in thyroid surgery
Permanent hypoparathyroidism following thyroid surgery is rare. Its prevalence is reported to be below 1–2% if surgery is performed by experienced thyroid surgeons. Parathyroid identification and preservation in situ with good vascular supply is the mainstay of safe thyroid surgery. However, if the parathyroid glands are damaged, autotransplantation should be undertaken to preserve their function. Parathyroid transplantation can be considered in three distinct modes of application: (I) fresh parathyroid tissue autotransplantation during thyroidectomy in order to reduce the risk of permanent hypoparathyroidism; (II) cryopreserved parathyroid tissue autotransplantation in patients with permanent hypoparathyroidism; (III) parathyroid allotransplantation in patients with permanent hypoparathyroidism when cryopreserved parathyroid tissue is not available for grafting. Nowadays, allotransplantation of cultured parathyroid cells without immunosuppression should be taken into consideration in selected patients as an alternative to calcium and vitamin D3 supplementation in management of permanent hypoparathyroidism. This paper is aimed to provide a review of current status of various parathyroid transplantation techniques in thyroid surgery.