Difficulties of parathyroidectomy after previous thyroidectomy.

Although the risks of reoperative thyroidectomy and parathyroidectomy have been well studied, the problems associated with parathyroidectomy after prior thyroidectomy have not been emphasized. Among a group of 282 patients who were treated for primary hyperparathyroidism in recent years at the University of Chicago Medical Center, 14 (4.8%) had undergone one or more previous thyroidectomies, and 6 others (2.1%) had undergone thyroid ablation with radioactive iodine as therapy for Graves' disease. Numerous difficulties were encountered during surgery in the postthyroidectomy group of patients as a result of scarring and fibrosis, prior recurrent laryngeal nerve injuries in 13%, the inability to known with certainty how many viable, normal parathyroid glands remained after previous operations, and the need for additional thyroid resection, mostly for associated malignant lesions. Preoperative vocal cord assessment, evaluation of prior operative and pathology reports, and localization studies with thallium-technetium scanning and ultrasonographic techniques were especially helpful. A "lateral approach" was used frequently during surgery. Each of these 14 patients was cured of the hyperparathyroidism. The postthyroid ablation group presented fewer intraoperative challenges, although in some patients the thyroid gland was virtually absent, which obscured the normal landmarks of the surgical field. Five of these six patients were cured of hyperparathyroidism. Parathyroidectomy after thyroidectomy presents many operative challenges to the surgeon and should be approached with the same care and concern that one reserves for a reoperative parathyroid operation.