Thyroxine replacement therapy's effect on preserving hearing after total thyroidectomy

BACKGROUND: Hypothyroidism can impair hearing function. With hypothyroidism, levothyroxine is used for thyroxine (T4) replacement therapy. Replacement therapy using levothyroxine, a synthetic form of T4 can successfully recover hearing, but it is unknown that if it can preserve the present hearing or not. Therefore, the author aimed to evaluate the thyroxine replacement therapy’s effect on patients’ hearing status after total thyroidectomy.METHODS: Patients with multi-nodular goiter (MNG) who underwent total thyroidectomy surgery were included in the study. Pre- and postoperatively obtained pure tone audiometry (PTA) tests and blood tests - such as for TSH, free thyroxine (fT4), free triiodothyronine (fT3) and calcium (Ca) levels - were compared.RESULTS: This study included 32 patients (female-to-male ratio, 22:10) who underwent total thyroidectomy. No significant difference between the pre- and postoperative PTA results was observed (Pright side=0.721 and Pleft side=0.652, paired t-test).CONCLUSIONS: Levothyroxine may preserve the patient’s hearing level in the absence of human thyroid hormone if TSH and fT4 levels can be sustained within the normal range. Patients should thus be under close control for thyroxine replacement therapy after total thyroidectomy.