UPPP usually involves removing the uvula and pharyngeal arches, partial removal of the soft palate and sometimes the tonsils. This procedure is performed under general anaesthetic. Research indicates that UPPP is often complicated by severe post-operative pain. Additionally there may be some long-term complications such as nasopharyngeal regurgitation, persistent palatal dryness, long-term voice changes and a partial loss of taste. UPPP is the only procedure that increases the width of the oropharynx. It has been shown that this could be useful in patients who palatal obstruction is caused by the side walls collapsing against each other.