Hemithyroidectomy

Hemithyroidectomy (also called a thyroid lobectomy) is an operation to remove one of the two lobes of the thyroid gland, along with the isthmus on the same side. The other lobe is left in place.

It is most commonly performed when: a thyroid nodule in one lobe returns indeterminate or suspicious biopsy results, requiring pathological assessment of the whole nodule; a benign but enlarging nodule causes symptoms; or a small, low-risk thyroid cancer is confined to one lobe.

A key advantage over total thyroidectomy is that the remaining lobe may produce enough thyroid hormone, avoiding the need for lifelong replacement therapy. However, around 20 - 30% of people eventually develop hypothyroidism in the years following hemithyroidectomy and will need levothyroxine. Regular thyroid blood tests after surgery are important for this reason.

The risks of hemithyroidectomy are similar to other thyroid surgery - voice changes from recurrent laryngeal nerve involvement, and a small risk to the parathyroid glands on the operated side - though the risk to all four glands is lower than with total thyroidectomy.