Surgical Procedure ‘Hypoglossal Nerve Stimulation Implant’ Introduced to Hong Kong

Surgical Procedure ‘Hypoglossal Nerve Stimulation Implant’ Introduced to Hong Kong
CUHK introduced in 2023 a new "hypoglossal nerve stimulation implant" to offer a novel treatment option for patients with sleep apnea. (Courtesy of CUHK)
To alleviate Obstructive Sleep Apnea (OSA), a procedure of Upper Airway Stimulation has been introduced in Hong Kong by the Chinese University of Hong Kong (CUHK). This is achieved by inserting a ‘Hypoglossal Nerve Stimulation Implant’ into the chest of the patient. Although this is a well-established procedure in the U.S., Hong Kong is only the third location in Asia to pioneer this procedure, following Japan and Singapore. The CUHK team introduced this technology last year and has completed three such operations so far, successfully improving the patients’ sleep apnea condition.

OSA is a common breathing condition during sleep. The upper respiratory tract muscles of the patient tend to relax during sleep, causing them to be blocked and depriving the patient of proper oxygen supply. This makes it difficult for patients to enter a deep sleep state and gain adequate rest, resulting in daytime drowsiness, difficulty concentrating, and even experiencing symptoms such as memory loss.

Without proper treatment, patients are more likely to develop cardiovascular diseases such as heart failure and stroke. According to research data, the incidence rate is 5 percent in middle-aged men, and 2 to 3 percent in women.

Continuous positive airway pressure (CPAP) respirator is a common treatment method for patients with moderate to severe obstructive sleep apnea, but the device often brings complaints of discomfort.

“Hypoglossal nerve stimulation implantation” is an emerging surgical intervention, in which the physician implants a nerve stimulator the size of a pacemaker under the clavicle of the patient. This device sends electrical stimulation pulses to the hypoglossal nerve to drive the Hyoid muscle activity that helps the patient expand their pharynx during sleep. The device is placed on the sensing part of the fourth rib to synchronize the treatment process alongside the patient’s breathing rhythm.

Dr. Natalie Leung Moon-wah, Clinical Associate Professor (honorary) of the Department of Otorhinolaryngology-Head and Neck Surgery at CU Medicine, said that “hypoglossal nerve stimulation implantation” is well established in the United States.

As the device is implanted in the body, patients have nothing extra to wear during sleep. However, since the hypoglossal nerve is one of the most delicate nerves in the human body and is responsible for the movement of most muscles in the tongue, it is a technically demanding surgical procedure.

The surgery requires an experienced and fully committed, multidisciplinary team, including sleep technicians, anesthetists, an intensive care team, and operation theater nurses for complicated post-operative and follow-up procedures.

The CUHK team has completed three cases of “hypoglossal nerve stimulation implantation” as of today. The patients’ sleep apnea index after surgery was reduced by an average of 77 percent, from an average of 44 counts of upper respiratory tract obstruction per hour to 10.3 counts, successfully improving their OSA condition from severe to mild.

Dr. Jason Chan Ying-kuen, Associate Professor of the Department of Otorhinolaryngology-Head and Neck Surgery at CU Medicine, CUHK, said that the team hopes to help promote relevant surgical training so that more patients with OSA can benefit.