P013 A pilot study for ultrasound examination of the pterygomandibular raphe to predict efficacy of mandibular advancement splint therapy in obstructive sleep apnoea

BACKGROUND: A lack of predictive indicators for mandibular advancement splint (MAS) efficacy limits their use in the treatment of obstructive sleep apnoea (OSA). The absence of a tendinous pterygomandibular raphe (PMR) in the lateral nasopharynx on MRI may predict MAS efficacy, however MRI is time and resource intensive. We aimed to assess the feasibility of ultrasound in determining PMR absence compared to MRI. METHODS: 10 healthy participants were recruited to undergo both MRI and ultrasound of the lateral airway. Surrounding anatomical landmarks were examined to establish the presence or absence of the PMR. These results will be compared to MRI to determine parameters on ultrasound which correlate to an absent PMR. PROGRESS TO DATE: 8 of the 10 participants have undergone both MRI and ultrasound, of which half were women, mean age 53 years, mean BMI 28 and mean AHI 3. In all 8 participants so far parameters for assessment of the PMR were identified and described, including presence of anatomical landmarks, localisation and width of the PMR space, and presence of a hyperechoic structure within the space. Comparison of these parameters with MRI to determine predictors of PMR presence or absence is currently underway. INTENDED OUTCOME AND IMPACT: Validation of ultrasound in the assessment for presence or absence of a tendinous PMR will enable further study of this structure as a predictive marker for MAS efficacy in OSA. This could assist clinicians in identifying suitable patients for MAS therapy.