A clefting or opening in the back part of the larynx or voicebox causes a child to aspirate. A cleft larynx is diagnosed in the operating room with a microlaryngoscopy. The clefts can range from mild to very severe. Mild clefts can be treated with no surgery or endoscopic surgery depending on the severity. More severe or larger clefts generally require an open surgical procedure. Each surgery must be tailored to the individual patient and condition.