Isthmectomy: a conservative operation for solitary nodule of the thyroid isthmus.

Purpose: To assess the results obtained in patients with nontoxic uninodular goiter confined to the isthmus undergoing isthmectomy.

Methods: Between April 1994 and June 2006, 330 consecutive patients with nontoxic uninodular goiter underwent thyroidectomy at our institution. In 31 patients, lesions were limited to the thyroid isthmus with evidence of benign or undetermined pathology on ultrasound-guided fine-needle aspiration biopsy. Total isthmectomy was performed.

Results: Preoperatively, thyroid nodules on ultrasonography were solid in 26 patients and mixed with cystic and solid components in 2. The mean size of nodules was 2.43 (+/- 0.88) cm. No intraoperative or postoperative complications occurred. Histological examination showed nodular hyperplasia in 29 cases, follicular adenoma in 1 and papillary thyroid carcinoma in 1. The patient with papillary carcinoma underwent bilateral lobectomy 7 days later. A total of 24 patients (77.4%) attended clinical visits at follow-up (mean 70,57 months). Ultrasonographic scanning revealed thyroid nodules in 17 patients, in 16 of which nodules range from one to five (0.5 to 2 cm in size) and further surgery was not indicated. One patient with a 4-cm nodule and tracheal displacement found at ultrasonography 2 years after isthmectomy had inconclusive results of FNAB. This patient was re-operated for completion thyroidectomy, which was successfully performed without technical difficulties. The detection of recurrent nodules was independent of the time elapsed since thyroid isthmectomy.

Conclusions: These findings document the feasibility and efficacy of isthmectomy in solitary thyroid nodules confined to the isthmus.