An adenoidectomy is a type of surgery that removes the adenoids, which are tiny tissue lumps that are in the back part of the throat (behind the nasal passages). They are lymphoid tissue masses behind the nose that can become infected or increase in size, which can result in problems including obstruction of breathing, sleep apnea, excessive snoring, and ear and sinus infections. There are some possible risks and side effects that are occasionally associated with this type of surgery, which is commonly performed on children.