0781 Neck circumference: A surrogate predictive variable of hypoglossal nerve stimulator therapy outcome

Abstract

Abstract Introduction Hypoglossal nerve stimulation therapy has strict eligibility requirements including a body mass index < 32kg/m2 for non-Medicare patients and body mass index < 35kg/m2 for Medicare patients. However, there is a wide variability in body fat distribution including variability between the sexes. We theorize that neck circumference may be a better surrogate predictive variable for hypoglossal nerve stimulation outcomes than body mass index. Methods A retrospective chart review was conducted at a single tertiary care center on adults who underwent hypoglossal nerve stimulator implantation by a single surgeon from March 2017 to October 2021. Baseline demographic data including neck circumference, diagnostic polysomnography and post-implantation polysomnography titration studies were collected. Patients without neck circumference measurements were excluded. Surgical success was defined by Sher criteria of apnea hypopnea index < 20 and reduction of the apnea hypopnea index by 50%. Results 75 patient charts were reviewed. 44 of these patients had neck circumference, body mass index, and AHI at effective voltage (AHI-v) data recorded. These were included in the analysis. Overall, AHI-v positively correlated with neck circumference (r2=0.20, p= 0.0025). Conversely, no significant association was apparent between AHI-v and BMI (r2=0.04, p=0.18). AHI-v appeared to worsen at a specific neck circumference of > 15 inches. T-test analysis showed significant difference in AHI-v comparing the groups of neck circumference ≤15in. vs > 15in. (x̄=27.58 vs 7.68, respectively, p=<0.001). However, no significant difference was found in mean BMI, age or baseline AHI between the neck circumference groups (p=0.15, 0.26, 0.10, respectively). Conclusion Findings suggest that neck circumference correlates to AHI at effective voltage during the post-implantation titration study. Our data indicates that neck circumference may be a better outcome predictor than BMI, baseline AHI or age for hypoglossal nerve stimulator effectiveness. Support (If Any)