Soft palate cephalometric changes with a mandibular advancement device may be associated with polysomnographic improvement in obstructive sleep apnea.

PURPOSE: It is unclear whether soft palate-associated changes in cephalometry associated with a mandibular advancement device (MAD) are independently associated with improvements in polysomnography (PSG) respiratory parameters in obstructive sleep apnea (OSA). METHODS: This retrospective review aimed to identify the association between soft palate-associated changes in cephalometry and PSG changes after application of an MAD. Korean patients diagnosed with OSA who underwent cephalometry with or without an MAD were enrolled. All the patients were evaluated after undergoing full-night PSG twice: once with an MAD and once without. Cephalometric findings were measured using an image analyzer. RESULTS: Mean apnea-hypopnea index significantly decreased with an MAD from 36.4/h to 14.7/h (p < 0.001). Retropalatal airway space significantly increased with an MAD from 6.6 to 7.3 mm (p = 0.013). Soft palate length also significantly decreased with an MAD from 43.6 to 42.3 mm (p = 0.02). Although these findings were shown by responders (patients with a reduction of apnea-hypopnea index by more than 50%), there were no significant changes in non-responders. However, retroglossal airway space did not significantly increase with an MAD even in responders. CONCLUSIONS: Improvement of OSA with an MAD can be predicted with soft palate-associated upper airway changes shown in cephalometry.

Radiographic and histologic characterization of tongue base tissues obtained by transoral robotic surgery in patients with obstructive sleep apnea.

OBJECTIVE: Our aim was to radiographically and histologically characterize the tongue base tissues removed after robotic surgery and to analyze their relationship with polysomnographic measurements in obstructive sleep apnea. METHODS: Medical records, radiographs and histologic specimen of the patients who underwent transoral robotic tongue base reduction surgery were retrospectively reviewed. Findings in computed tomography (CT) images, histopathological features of the removed tongue base tissues, and respiratory parameters in polysomnography were compared and analyzed. RESULTS: Surgical specimens and CT images were available from 13 patients (aged 29-61 years). Histologic examination showed that the removed tissues comprised four layers-epithelial, lymphoid follicular, glandular, and muscle tissue. The median (interquartile range) thickness of the epithelial, lymphoid, and glandular layers was 0.29 (0.24-0.44) mm, 3.37 (1.67-4.75) mm, and 3.75 (3.45-4.10) mm, respectively. The lymphoid layer thickness on CT was correlated with that in the histologic section (r=0.967, p<0.001). However, the thickness of each layer had no significant correlation with the polysomnographic parameters. CONCLUSION: The tongue base tissue removed by transoral robotic surgery in OSA patients comprised four distinctive layers including epithelial, lymphoid follicular, glandular and muscular layers. These layered structures could also be discriminated in the CT images.

A Comparison of Different Success Definitions in Non-Continuous Positive Airway Pressure Treatment for Obstructive Sleep Apnea Using Cardiopulmonary Coupling.

STUDY OBJECTIVES: The definition and the criteria for the successful treatment of obstructive sleep apnea vary, depending on the study. This study aimed to compare different success criteria of non-continuous positive airway pressure (non-CPAP) treatment for obstructive sleep apnea in terms of sleep quality by using cardiopulmonary coupling. METHODS: We included 98 patients who had been treated with sleep surgery or with a mandibular advancement device at our sleep clinic from January 2011 to March 2013. The success and failure groups were divided by 6 criteria that have been used in the literature. The validity of each of the 6 criteria was evaluated by cardiopulmonary coupling-based sleep quality. RESULTS: The parameters of cardiopulmonary coupling indicated that sleep quality improved with non-CPAP treatment: low-frequency coupling decreased from 57.4% ± 17.7% to 46.9% ± 16.5%, whereas high-frequency coupling increased from 30.2% ± 17.1% to 37.4% ± 16.7%. In multiple regression analysis, only the criterion of a reduction in the apnea-hypopnea index greater than 50% was significantly associated with sleep quality improvement (p = 0.016; 95% confidence interval, 1.008-1.076 in the high-frequency coupling increment; p = 0.001; 95% confidence interval, 1.025-1.099 in the low-frequency coupling decrement). CONCLUSIONS: Cardiopulmonary coupling analysis showed that a reduction in the apnea-hypopnea index of more than 50% might be the optimal criterion to determine the success or failure of non-CPAP treatment in terms of sleep quality.