Palate shape is associated with Unilateral Hypoglossal Nerve Stimulation Outcomes

Objective: The aim was to determine the potential association between palate shape and unilateral hypoglossal nerve stimulation (HNS) outcomes. Methods: Preoperative drug-induced sleep endoscopy (DISE) videos were reviewed and scored by 3 blinded reviewers to determine airway narrowing at the hard-soft palate junction (HP), soft palate genu, and inferior velum, as described by Woodson (2014). Scoring was as follows: 1-open airway, 2-narrow, 3-severe narrowing. Overall palate shape (oblique, intermediate, or vertical) was determined based on prior criteria. Successful surgical treatment was defined by the HNS titration polysomnogram as a reduction of >= 50% in the apnea-hypopnea index (AHI) to <15 events/h. Results: Of 332 adults, the majority was male (77%) with an average BMI of 29.2 +/- 3.6 kg/m(2). Overall success rate was 73%. Success rate was lower in patients with vertical palate shape compared with the other shapes (56% vs. 75%, p = 0.029). HP score 3 compared with scores 2 and 1 was associated with lower success rates (60% vs. 76%, p = 0.028), but genu and velum scores were not associated with outcomes. Patients with both HP score 3 and complete oropharyngeal lateral wall-related obstruction had notably worse outcomes (22% vs. 74%, p = 0.026). HP score 3 (OR 0.45, 95%CI 0.22-0.92) and vertical palate shape (OR 0.33, 95%CI 0.15-0.78) were independently associated with lower odds of surgical response after adjustment for DISE findings, age, gender, and BMI. Conclusion: Vertical palate shape and narrowing at the hard-soft palate junction are independently associated with lower HNS surgical success rates.