Parathyroid venous sampling: anatomic considerations and results in 95 patients with primary hyperparathyroidism.

The most successful method of preoperative parathyroid adenoma localization is achieved by assay of venous samples for parathyroid hormone content. Selective sampling of the small veins draining the parathyroid glands increases the accuracy of prediction. Our review of 95 recent cases confirms an efficacy of prediction in 87.5%. The anatomy of the veins draining the parathyroid glands is outlined and we note variations that may occur in the inferior thyroid venous drainage. We consider contralateral venous flow to be of greater significance than has been recognized hitherto. This cross flow occurs through the thyroid plexus, and also via the vertebral venous plexus posteriorly and the anterior jugular veins in the front of the neck. Recent improvements in hormone assay combined with greater knowledge of the parathyroid venous drainage pattern of the individual patient may further improve the prediction rate.