The Impact of Pharyngeal Opening Pressure on Hypoglossal Nerve Stimulation Surgery

Introduction: A prior small cohort study reported that a lower preoperative pharyngeal opening pressure (PhOP) during drug-induced sleep endoscopy (DISE) predicts better treatment response to hypoglossal nerve stimulation (HGNS) in patients with obstructive sleep apnea (OSA). Our objective was to assess this association in a larger, more diverse cohort of patients.

Methods: This retrospective cohort included 63 patients who underwent HGNS implantation at a tertiary academic medical center. Patients with full night post-op efficacy home sleep studies were included. Response to treatment was defined as a ≥50% reduction in the apnea-hypopnea index (AHI) and a postoperative AHI of < 15.

Results: The cohort included 63 patients: 66.7% men, mean age 58.2±10.7 years, body mass index (BMI) 28.6±3.3, AHI 37.9±16.2. There were 23 patients (36.5%) who were responders while 40 patients (63.5%) were nonresponders. Responders exhibited lower mean PhOP compared to nonresponders but it did not reach statistical significance (p = 0.070). In a multivariable logistic regression analysis adjusting for age, sex, preimplant AHI, and DISE-PhOP, lower BMI was a significant predictor of treatment success (OR 0.72, 95% CI 0.59-0.89; p = 0.005). No cutoff of PhOP was found to predict outcomes.

Conclusions: Pharyngeal opening pressure as measured during DISE PAP was not found to be a significant predictor of HGNS treatment response, which contrasts prior research demonstrating improved outcomes with lower palatal opening pressure. Lower BMI, as demonstrated in previous studies, did help predict treatment success. These findings demonstrate that PhOP, as currently measured, may not improve patient selection in HGNS therapy, but further research is needed to determine the impact of upper airway collapsibility on HGNS outcomes.