CUHK pioneers upper airway stimulation for obstructive sleep apnoea

Otorhinolaryngologists at the Chinese University of Hong Kong (CUHK) have introduced upper airway stimulation (UAS) as a treatment option for obstructive sleep apnoea (OSA), making Hong Kong one of the three locations in Asia where this surgical intervention is available.

“Continuous positive airway pressure [CPAP] therapy is the standard treatment for OSA, but poor adherence has been reported worldwide due to device-related issues and patients’ clinical conditions, such as air leak and nasal congestion,” said Dr Jason Ying-Kuen Chan of the Department of Otorhinolaryngology, Head and Neck Surgery at CUHK.

“A significant proportion of OSA patients [26 percent] prescribed CPAP therapy do not use it,” added Dr Natalie Moon-Wah Leung of the Department of Otorhinolaryngology, Head and Neck Surgery at CUHK. “Notably, 48 percent of them are without other therapy and 33 percent never return to their physicians. A significant proportion of patients with OSA are therefore untreated.” Untreated OSA is associated with increased risks of excessive daytime sleepiness, cardiovascular diseases, diabetes, stroke, and mood disorders. [Rev Environ Health 2019;34:153-169]

UAS has become a well-established treatment option for patients with moderate-to-severe OSA with CPAP failure or intolerance in the US since its FDA approval in 2014. It is delivered with a small neurotransmitter implanted beneath the clavicle, which simulates the hypoglossal nerve to activate the genioglossus muscle of the tongue and dilate the pharynx during sleep. [www.accessdata.fda.gov/cdrh_docs/pdf13/P130008S039B.pdf]

“As the device is implanted in the body, patients have no external device to wear during sleep, [providing a solution to those with low adherence to CPAP],” added Leung.

However, UAS therapy remains relatively rare in Asia as the surgical procedure is technically demanding.  “The hypoglossal nerve is one of the most delicate nerves in the human body, which provides motor innervation of tongue muscles,” explained Leung. “Neurotransmitter implantation for UAS requires a fully committed, experienced and multidisciplinary team consisting of sleep technicians, anaesthetists, intensive care professionals, and theatre nurses.”

“Hong Kong is the third location in Asia to provide UAS, after Singapore and Japan,” highlighted Chan. As of February 2024, the CUHK team had completed the surgical procedure in three patients (mean operation time, 192 minutes), with satisfactory outcomes. At 6 months after surgery, patients receiving UAS therapy showed a 77 percent drop in Apnoea-Hypopnoea Index vs baseline (mean AHI, from 45 events/hour to 10.3 events/hour), with mean Epworth Sleepiness Scale (ESS) score dropping from 13 to 11, indicating improvement in severity of OSA from severe to mild. All patients were discharged on day 2 without any significant adverse events or surgical complications.

The local experience was generally consistent with 5-year outcomes of the STAR trial, which showed improvements in sleepiness and respiratory outcomes in UAS-treated patients. Additionally, the ADHERE UAS Registry showed that mean objective therapy use was 5.7 hours per night, with 95 percent of users preferring UAS over PAP. [Otolaryngol Head Neck Surg 2018;159:194-202; Laryngoscope 2020;130:1333-1338] “UAS is a safe and effective treatment in select OSA patients, showing high treatment adherence and patient satisfaction,” concluded Leung.