What are the effects of a partial thyroidectomy?

Usually no effect: On production of thyroid hormone- remaining thyoid tissue enough to give normal levels.

It removes: A portion of your thyroid. You will definitely need life-long replacement with brand name T4 after the surgery. There are some risks, including potential damage to laryngeal nerve and parathyroid glands, but risks should be minimal with a good surgeon. Depends upon the indication for the surgery in the first place.