Introduction:
Selective upper airway stimulation (sUAS) is a novel treatment modality for patients
with moderate-to-severe obstructive sleep apnea (OSA) refractory to continuous positive
airway pressure (CPAP) therapy. Previous studies have demonstrated that changing electrode
configurations (EC) or pulse intensity (PI) can lead to different field currents,
affecting airway dimension and therapy success.
The purpose of our study is to quantify how changes in EC and PI influence airway
dimensions during drug-induced sleep endoscopy (DISE) in patients who underwent sUAS.
Method:
30 patients with an implanted hypoglossal nerve stimulator underwent DISE in the supine
position. The cross-sectional, anterior-posterior, and lateral dimensions at two anatomical
levels (retropalatal and retroglossal) were measured at baseline and after stimulation.
Airway dimensions were scored by two separate investigators. Patients received PI
at 100% of their functional threshold (FT) and 125% FT using three EC – one bipolar
(plusminusplus) and two unipolar configurations (minusminusminus, offminusoff).
Result:
To maintain small inter-rater variability in our scoring, 25 of the 30 patients were
chosen for analysis. Although we did not observe consistent increases in airway dimension
at every level and EC when raising PI from 100% to 125%, we did see at least one EC
per patient where increments in PI resulted in larger airway. Comparing all ECs together,
44% of all 25 patients reveal a clear increasement while using the bipolar configuration,
followed by the unipolar ones. Individual deviations can be seen.
Conclusion:
We conclude that higher PIs and use of bipolar EC can lead to greater airway dimensions.
Despite these findings, adjusting EC and PI may be warranted if a patient is not responding
to sUAS therapy.
