Discussion
hypopneas, respiratory effort-related arousals, obstructive apneas, hypopnea, apnea, daytime sleepiness, snoring, arousals, OSAS, AHI reduction, Daytime sleepiness
MINOR, RESPIRATORY EFFORT-RELATED AROUSAL, POSITIVE
The presented study examined the Ronch®AP palatal device as an alternative conservative treatment option in OSAS therapy. Even though the therapeutic approach to treat OSAS by stenting the retropalatinal space is not novel, little research has been published [The effectiveness of Ronch®AP was examined in a randomized controlled clinical trial over 4 weeks. The study’s strength lies in its design. A controlled, randomized trial minimizes the risk of selection bias. Moreover, cardiorespiratory polysomnography represents the highest diagnostic standard for OSAS and therapeutic management. All polysomnographic testing was conducted in accordance with international standards. The observation interval of 4 weeks was considered suitable for the studies' objective. It allowed the evaluation of the effectiveness of Ronch®AP while upholding ethical standards. As the control group did not receive any treatment during the 4-week time interval, a longer observation period would not have been ethically acceptable.In comparison with the control collective, AHI was significantly reduced from 35.34 ± 14.9/h to 19.18 ± 14.93/h (Analyzing treatment success in regard to different AHI-related success criteria shows that the therapy group performed better in all three categories. By reducing AHI < 10 31.8% patients (The lack of statistical significance in regard to these predictors might be attributed to the modest size of the examined subgroups.The statistically relevant improvement of AHI under Ronch®AP compared to the control group was not found in other sleeping parameters. However, measured by their baseline values significant improvements were observed within the therapy group in regard to apnea index and hypopnea index, the total amount of snoring sounds and snoring index. Positive trends transpired in regard to the total amount of obstructive apneas and hypopneas and the amount of respiratory effort-related arousals. In addition, a minor shift in the sleep profile toward a higher share in deep sleep at the expense of light sleep must be positively acknowledged. Patients under Ronch®AP therapy were five times less likely to awaken after sleep onset. In contrast to the Ronch®AP treatment that had no effect on minimal and average oxygen desaturation, De Bruijn observed a significant increase in both parameters under Velumount® [The fact that objective improvements (e.g., AHI reduction) are also reflected in patients’ positive subjective assessment of treatment effectiveness is highly beneficial for compliance and therapy adherence. Daytime sleepiness and sleep quality were significantly improved compared to patients without treatment. Considering that daytime sleepiness is one of the main symptoms of OSAS and that patients frequently suffer from poor sleep quality due to frequent awakenings and arousals, these results are encouraging. Different studies on Velumount® therapy support the evidence given in the presented study that palatal oral appliances reduce ESS. This is seen in patients’ positive evaluation of palatal appliances in OSAS therapy [In total, this study’s findings are promising. However, the results should be seen in the light of their limitations. The analysis performed only included patients with moderate and severe OSAS. Even though the results for the presented cohort are significant, the study is not able to give evidence for the effectiveness of Ronch®AP therapy for mild forms of OSAS. Furthermore, in future studies reliability and quality of results could be enhanced by choosing larger patient cohorts and assessing the influence of interesting variables, such as location of obstruction occurrence. Data were reduced by early drop-outs in the adjustment process and by incomplete records. It will be interesting to assess if potential predictors for treatment success are identified in future studies with larger sampling sizes. However, the acknowledgement of drop-outs provides intrinsic information on tolerance capacity of Ronch®AP. As the study presents a first-time scientific evaluation of Ronch®AP, the chosen observation period of 4 weeks surely allowed obtaining important information on principal treatment effectiveness. On the other hand the study was not designed to obtain information on long-term compliance and treatment success.