Outcome of surgery for Graves' disease re-examined.

The outcome of surgery for Graves' disease in terms of early and late morbidity was studied in 161 patients undergoing subtotal thyroidectomy in the 10-year period 1976-1985. Eighty of these patients had a minimum follow-up of 5 years. There was a low operative morbidity and a zero mortality. The weight of thyroid tissue preserved (in the range 5-10 g) influenced the prevalence of hypothyroidism at one year and at five years. There was a cumulative incidence of hypothyroidism which could not be reliably predicted from biochemical results during the first year. Over 60 per cent of patients with subclinical hypothyroidism at 4 months (63 per cent) or 1 year (70 per cent) did not subsequently need thyroxine replacement within 5 years. Patients remained at risk of developing recurrent toxicity indefinitely and the risk was significantly greater in patients with small goitres (less than 50 g). Our results may be improved by leaving larger remnants (9-10 g) in most patients and smaller remnants (2-4 g) in those with small glands in whom alternative treatment, which is to be preferred, is not acceptable. After subtotal thyroidectomy for Graves' disease lifelong follow-up is necessary.