A hemithyroidectomy is the surgical removal of only one of the thyroid lobes. Research says that post-operative hypothyroidism (hypothyroidism caused by the operation) develops in 5.6-48.9% of patients who undergo this procedure, and is actually the most common complication seen of the surgical procedure.Post-operative hypothyroidism, both low-grade and overt, occur because when one of the lobes is removed, the remaining lobe cannot compensate after the absence of the other lobe. As a result, thyroid hormone levels go down.Studies have shown that treating with levothyroxine often corrects hypothyroidism that occurs post-operatively. In some cases, this type of hypothyroidism is short lived, and spontaneous recovery of normal thyroid function is seen in a handful of patients who are not treated with levothyroxine. Nobody’s physical reaction to a lobectomy will be the same. This is why it is important to be monitored after thyroid surgery, even a simple lobectomy. Continued thyroid testing is crucial to ensure that the correct amount of thyroid hormone is being used to keep thyroid hormone levels in an excellent balance.