Occurrence of problems after three techniques of bilateral thyroidectomy in cats.

Bilateral thyroidectomy was performed in 106 cats with hyperthyroidism by one of three techniques: original intracapsular, modified intracapsular, or modified extracapsular. Hypocalcemia was detected in the first 3 days after surgery in 11 (22%) of 50 cats treated by the intracapsular technique, 10 (33%) of 30 cats treated by the modified intracapsular technique, and 6 (23%) of 26 cats treated by the modified extracapsular technique. Hypocalcemia was classified as mild or severe. No signs of hypoparathyroidism developed in any of the 13 cats with mild hypocalcemia. Of the 14 cats with severe hypocalcemia, 8 had clinical signs of hypoparathyroidism before and during treatment with calcium and vitamin D, 3 were treated and no clinical signs developed, 2 were not treated but no clinical signs developed, and 1 was lost to follow-up. No cat required permanent calcium or vitamin D supplementation after surgery. Severe hypocalcemia and clinical signs of hypoparathyroidism occurred in 3 (6%) of the 50 cats treated by the intracapsular technique, 4 (13.3%) of the 30 cats treated by the modified intracapsular technique, and 1 (3.8%) of the 26 cats treated by the modified extracapsular technique. Twelve cats had recurrence of hyperthyroidism at a median time of 23 months. The intracapsular technique was used in 11 of these cats, and the modified extracapsular technique was used in 1. No clinical signs of hypothyroidism were detected in any of the cats. The modified intracapsular and modified extracapsular techniques of bilateral thyroidectomy are effective procedures for the treatment of feline hyperthyroidism.