Oral appliances for obstructive sleep apnea

Antero-Posterior Mandibular Excursion in Obstructive Sleep Apnea Patients Treated with Mandibular Advancement Device: A Retrospective Cohort Study

Since obstructive sleep apnea (OSA) management with a mandibular advancement device (MAD) is likely to be life-long, potential changes in mandibular movements during therapy should be investigated. The purpose of this study was to use a method that has already been shown to be reliable in order to determine whether the range of antero-posterior mandibular excursion, the procedure upon which MAD titration is based, varies between baseline (T0) and at least 1 year of treatment (T1). The distance between maximal voluntary protrusion and maximal voluntary retrusion determined using the millimetric scale of the George Gauge was retrospectively collected from the medical records of 59 OSA patients treated with the MAD and compared between T0 and T1. A regression analysis was performed to evaluate the influence of treatment time, MAD therapeutic advancement and the patient's initial characteristics in excursion range variation. A statistically significant increase of 0.80 ± 1.52 mm (mean ± standard deviation, p < 0.001) was found for antero-posterior mandibular excursion. The longer the treatment time (p = 0.044) and the smaller the patient's mandibular excursion at T0 (p = 0.002), the greater the increase was. These findings could be explained by a muscle-tendon unit adaptation to the forward mandibular repositioning induced by the MAD. During MAD therapy, patients can develop a wider range of antero-posterior mandibular excursion, especially those with a smaller initial excursion capacity.

Upper airway collapsibility in patients with OSA treated with continuous positive airway pressure: a retrospective preliminary study

STUDY OBJECTIVES

To investigate the prevalence of mildly collapsible upper airways (defined by therapeutic continuous positive airway pressure [CPAP] values ≤ 8 cm H₂O) in moderate to severe obstructive sleep apnea patients treated with CPAP and to determine their clinical, functional, and nocturnal polysomnographic characteristics.

METHODS

Eighty-seven patients with moderate to severe obstructive sleep apnea consecutively treated with CPAP were retrospectively investigated. Two nocturnal home sleep portable monitoring studies were performed at baseline and during treatment. Participants were categorized according to therapeutic CPAP values: ≤ 8 cm H₂O (group 1), 8-12 cm H₂O (group 2), ≥ 12 cm H₂O (group 3). Anthropometric, awake respiratory function, symptoms, comorbidities, and nocturnal home sleep portable monitoring studies data were collected.

RESULTS

Mild upper airway collapsibility (therapeutic CPAP values ≤ 8 cm H₂O) was present in 25.3% of patients. They showed more favorable apnea-hypopnea index, oxygen desaturation index, mean nocturnal saturation, sleep time with oxygen saturation < 90%, desaturation nadir, and supine position. Oxygen desaturation index showed a weak association with anatomical collapsibility. Using the receiver operating characteristic curve, the area under the curve for the oxygen desaturation index vs CPAP pressure requirements ≤ 8 cm H₂O was low and oxygen desaturation index ≤ 40.8/h showed a sensitivity of 63.3% and a specificity of 69.2% to detect patients with mild collapsibility.

CONCLUSIONS

A quarter of moderate to severe patients under CPAP therapy had mild collapsibility and were likely to also be good candidates for alternative and better tolerated non-CPAP therapies. Baseline anthropometric, clinical, and respiratory function characteristics did not predict mild upper airway collapsibility determined by CPAP pressure requirements ≤ 8 cm H₂O.

The effectiveness of mandibular advancement devices in the treatment of obstructive sleep apnoea in adults: a methodological quality assessment of systematic reviews

BACKGROUND AND OBJECTIVES

There is growing interest in the use of mandibular advancement devices (MADs) for the treatment of obstructive sleep apnoea (OSA). Many systematic reviews (SRs) have investigated their effectiveness, but the applicability of SR results is affected by their methodological quality. This study critically appraises the methodological quality of SRs on this topic using a more detailed and updated version of A MeaSurement Tool to Assess systematic Reviews (AMSTAR).

MATERIALS AND METHODS

The literature was searched for SRs on MAD effectiveness in adults (≥18 years of age) for OSA treatment as compared with other non-surgical or surgical interventions or no intervention. Any objective or subjective measures of treatment outcome were considered eligible. AMSTAR2 was used to assess methodological quality.

RESULTS

The literature search yielded 64 potential reports; 10 met the eligibility criteria. All SRs had more than one critical flaw in AMSTAR2, so their methodological quality was rated as critically low. The most common issues included non-registration of study protocol, absence of list of excluded studies, no acknowledgment of fundings of included studies, no impact of risk of bias on SR results or interpretation and discussion of results, and data extraction not in duplicate.

LIMITATIONS

If a SR was not clearly identified by title or abstract as a SR or meta-analysis, it may have been missed during the screening process.

CONCLUSIONS

The methodological quality of SRs was suboptimal and warrants further improvement in order to provide strong evidence of MAD effectiveness and increase applicability of SR results for clinical decision-making.

A review of fluid-structure interaction simulation for patients with sleep related breathing disorders with obstructive sleep

Obstructive sleep apnea is one of the most common breathing disorders. Undiagnosed sleep apnea is a hidden health crisis to the patient and it could raise the risk of heart diseases, high blood pressure, depression and diabetes. The throat muscle (i.e., tongue and soft palate) relax narrows the airway and causes the blockage of the airway in breathing. To understand this phenomenon computational fluid dynamics method has emerged as a handy tool to conduct the modeling and analysis of airflow characteristics. The comprehensive fluid-structure interaction method provides the realistic visualization of the airflow and interaction with the throat muscle. Thus, this paper reviews the scientific work related to the fluid-structure interaction (FSI) for the evaluation of obstructive sleep apnea, using computational techniques. In total 102 articles were analyzed, each article was evaluated based on the elements related with fluid-structure interaction of sleep apnea via computational techniques. In this review, the significance of FSI for the evaluation of obstructive sleep apnea has been critically examined. Then the flow properties, boundary conditions and validation of the model are given due consideration to present a broad perspective of CFD being applied to study sleep apnea. Finally, the challenges of FSI simulation methods are also highlighted in this article.