Hypoglossal nerve stimulation for OSA
Reviewed by Vik Veer

Hypoglossal nerve stimulation has been lauded as the great new surgical treatment panacea for obstructive sleep apnoea (OSA). This meta-analysis includes 12 studies with a total of 350 patients, including the five-year follow-up data from the STAR trial which was originally published in the NEJM. Considering this is a group of continuous positive airway pressure (CPAP)-failure patients, the quoted surgical success rate of approximately 70% (success defined by the Sher criteria - 50% reduction in apnoea-hypopnoea index (AHI) and overall AHI less than 20/hour) at five years seems quite reasonable. There is also an average AHI reduction rate of 18/hour, and the Epworth score was reduced by five. What confused me is that there are currently at least 5000 patients in the implant registry, but for some reason this data has not been published yet. Also, this paper states that there was “only” a 6% complication rate, however this is actually the major complication rate. After five years, eight of the 126 patients who remained in the trial required an operation to reposition or re-implant a part of the device. The minor complication rate was much higher, with up to 60.3% experiencing discomfort from the electrical stimulation. The other point that worried me was that the STAR trial data was not based on an entire night’s data, but instead on the best values gained during the test night. Also, only 57% managed to complete the five-year follow-up. This all sounds rather irregular, and somewhat disingenuous considering the publicity surrounding this technology. On saying that, the other trials do appear to represent relatively standard sleep study methods. In summary, this paper shows that hypoglossal nerve stimulation confers a significant long-term benefit in patients with moderate to severe OSA. There are, however, questions about the robustness of the device, and the actual clinical benefit. It is likely that this therapy is only suitable for a percentage of patients (probably only tongue base collapse patients), rather than a second stage treatment after CPAP for all patients. 

Hypoglossal nerve stimulation long-term clinical outcomes: a systematic review and meta-analysis.
Costantino A, Rinaldi V, Moffa A, et al.
SLEEP AND BREATHING 2019
[Epub ahead of print]