LAUSR

Hypoglossal nerve stimulation (HNS) for the treatment of obstructive sleep apnea (OSA) in patients who have failed positive airway pressure (PAP) therapy for one reason or the other is now standard of care. Once the device is implanted and activated, voltage to stimulate the nerve has to be titrated over time, ultimately leading to an HNS titration study. There are 4 possible electrode configurations to stimulate different fibers in the nerve that can be employed for treatment. We present a case of a patient who was a challenge with worsening of OSA with Inspire. A 65-year-old woman with hypertension, and severe OSA, intolerant of positive airway pressure or oral appliances was implanted with Inspire. Post activation, there was symptomatic improvement with reduction of overall apnea-hypopnea index (AHI) from 34 per hour of sleep to 6.3 per hour. However, patient slept exclusively on the sides with evidence of significant residual disease in REM sleep. During subsequent weeks, patent reported inability to restrict position and discomfort and anxiety associated with up titration. Both awake endoscopy and advanced overnight HNS titration were pursued. All 4 electrode configurations were tested during both procedures. With the exception of (minus-plus-minus) configuration, there was worsening of sleep disordered breathing and higher residual AHI of 60 per hour on polysomnography and evidence of poor tongue motion and collapsed velopharynx on awake endoscopy. Inspire settings were readjusted to (minus-plus-minus) configuration with instructions for very slow outpatient uptitration and co-management of anxiety and discomfort with anxiolytics and sleep aids. We make two important conclusions from this case. Firstly, although there are established criteria for patient selection for hypoglossal nerve stimulation therapy, certain other factors that impact success which are not as easily defined include the patients’ expectations, tolerance of discomfort, propensity to anxiety and personality type which impact the ability to successfully titrate voltage with the Inspire device over time. Secondly, as the tongue is a complex muscle, both under titration and over titration may be counterproductive and additionally, electrode configuration may also have varying effects on tongue protrusion and impact success.