Treating obstructive sleep apnea with hypoglossal nerve stimulation.

PURPOSE OF REVIEW: Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent pharyngeal collapse secondary to sleep-induced hypotonia of peri-pharyngeal structures. Therapy for OSA is sometimes poorly tolerated and not always effective. The current study reviews a new treatment modality, hypoglossus stimulation, recently evaluated by multiple physiological studies and currently assessed by several clinical studies.

RECENT FINDINGS: A phase-I, implantable hypoglossus nerve stimulation multicenter study was published in 2001. Significant reduction in apnea-hypopnea index (AHI) was reported in seven of the eight implanted OSA patients, but technical faults precluded prolonged follow-up. Over the past 2 years, three new hypoglossus nerve stimulation systems have been evaluated in more than 60 OSA patients. In adequately selected patients, a more than 50% reduction in AHI was observed. Usually, a decrease in OSA severity from moderate-severe to mild-minimal can be achieved.

SUMMARY: Ongoing research, including recent initiation of a large multicenter phase-III study, suggests that hypoglossus nerve stimulators are likely to be available as a new treatment modality within a few years. Additional data are needed to define which OSA patients are most likely to benefit from hypoglossus nerve stimulation. Continuous refinement of electrodes design is likely to improve stimulation efficacy in coming years.