Causes of the failed cervical exploration for primary hyperparathyroidism.

Over a period of 42 years, 581 patients with presumed hyperparathyroidism underwent an initial cervical exploration. Abnormal parathyroid glands were removed from 495 patients (85.2%). There was a greater probability of operative success in women, patients over 50 years of age, and patients with hypercalcemia, hypertension, or nonspecific abdominal pain. There was no association of operative outcome with some of the "classic" manifestations of hyperparathyroidism--peptic ulcer disease, neuropsychiatric symptoms, pancreatitis, bone disease, or urolithiasis. The probability of surgical success improved with time, increasing from 56 per cent in the 1950s to 97 per cent in the present decade. This improvement appears to be related to greater operative experience, since all four parathyroid glands were more likely to be found with increased experience, and there was a strong correlation between finding four parathyroids and achieving persistent normocalcemia. The most common causes of operative failure were inaccurate calcium assays (the patient was not truly hypercalcemic), an inappropriate diagnosis ("normocalcemic hyperparathyroidism"), and surgical inexperience. These three factors accounted for at least three fourths of all negative explorations. More accurate diagnostic studies, and careful exploration by an experienced surgeon should maximize the probability of a successful operation for primary hyperparathyroidism.