Apnex Medical Inc. said it received European approval to sell its treatment for obstructive sleep apnea, a sleeping disorder that makes it difficult for patients to breathe while they are asleep.

The St. Paul-based company implants a device that stimulates a patient’s nerve that controls the muscle in the tongue, keeping the airway open while a patient is asleep. The stimulation is based on the patient’s breathing pattern.

More than 100 million people worldwide have obstructive sleep apnea, according to the World Health Organization.

CEO Chas McKhann said getting the approval was a “key milestone” for Apnex Medical, which was founded in 2006.

“We are excited to bring this innovative new therapy to Europe,” McKhann said.

The company plans to sell the treatment on a limited basis in Europe next year, but the price hasn't been determined yet, McKhann said. The company is working on getting approval to sell the treatment in the United States.