Oral Appliances for Severe Positional Obstructive Sleep Apnea Syndrome: A Case Report

Abstract

Severe positional obstructive sleep apnea syndrome (POSAS) is a common clinical respiratory disorder with an incidence of 26.7% to 74.5%. Continuous positive airway pressure (CPAP) combined with positional therapy is the gold standard of treatment. However, a mandibular advancement device (MAD) is an effective alternative to CPAP when compliance with CPAP is low or if CPAP is rejected by the patient. A 63-year-old Caucasian male (BMI 26.1 kg/m²) complaining of repeated episodes of daytime sleepiness and heavy snoring was diagnosed with POSAS and treated with a MAD. After two years, polysomnographic (PSG) control analysis showed a significant reduction in the number of obstructive sleep apnea/hypopnea episodes per hour (AHI) by 58.9% in the lateral position and 75.5% in the supine position, complete remission of symptoms, a significant reduction in the severity of POSAS, and an overall improvement in quality of life. No adverse events or reduction in compliance were observed during the follow-up period. For severe POSAS, MADs may be an alternative method that is well tolerated by patients and has a good safety profile.

1. Introduction

Obstructive sleep apnea syndrome (OSAS) is a common clinical respiratory disorder characterized by the repeated occurrence of partial or complete upper airway obstruction, which can lead to a series of symptoms such as apnea, dyspnea, snoring, sleep fragmentation, and daytime sleepiness with cognitive and attention deficits that significantly affect the quality of life of affected patients [1]. Although the incidence is higher in the middle-aged population (4% in men and 2% in women) [2] and increasing among the elderly (28% to 67% in elderly men and 20% to 54% in elderly women) [3], younger people and children may also be affected [4,5]. Positional OSA (POSAS), first described by Cartwright in 1984 [6], is prevalent among OSA patients by 26.7% to 74.5% [7]. According to the Cartwright definition, POSAS is diagnosed when the number of obstructive sleep apnea/hypopnea episodes per hour (AHI) is at least twice as high in the supine position than in the lateral position [6].

The diagnosis of POSAS is made by the patient’s medical history and polysomnography (PSG) [8], which allows the correct determination of the sites of obstruction and time in the supine position. To date, various surgical and non-surgical treatment approaches have been developed for OSAS in general [9,10,11], but positional therapies, alone or in combination with continuous positive airway pressure (CPAP), are recommended as first-line treatment for POSAS patients, depending on the severity of the condition. Positional therapies consist of sleep position trainers worn during sleep that are designed to detect the patient’s position using an accelerometer; if a supine position is detected, the system vibrates to prompt the patient to turn to a non-supine position [7]. While positioning therapy alone may not have a positive impact on outcomes, CPAP has several disadvantages. Approximately 5–15% of patients cannot tolerate CPAP due to discomfort, claustrophobia, perception of low benefit, and dryness of the nose or mouth [12]. Additionally, CPAP compliance (defined as CPAP use of more than 4 h per night and more than 70% of nights) varies from 40% to 85% due to excessive daytime symptoms such as sleepiness and neurocognitive changes [11,13,14], psychosocial factors, and comorbidities such as insomnia, restless leg syndrome, periodic limb sleep, and complex sleep apnea [15].

The mandibular advancement device (MAD) is an alternative treatment option to CPAP, with good long-term compliance [11,16]. It provides a 50% reduction in AHI while reducing snoring, daytime sleepiness, neuropsychological disturbances, and cardiovascular risks similar to CPAP [11]. The main side effects, many of which are transient and associated with mild discomfort [17], when using MADs include temporomandibular joint-related side effects—such as transient morning jaw pain, persistent temporomandibular joint pain, tenderness of masticatory muscles, and joint noises—side effects related to intraoral tissues, occlusal changes, damage to teeth or restorations (tooth mobility and fractures or damage to dental restorations), and appliance problems (appliance breakage, allergies to appliance material, gagging, and anxiety) [18].

Several meta-analyses and randomized controlled trials have shown that CPAP and MADs demonstrate similar improvements in subjective symptoms such as anxiety and depression [19,20], quality of life, simulated driving performance [21], common sleep disturbances, and self-reported symptoms [22], with irrelevant differences in cardiovascular changes [23,24]. The updated 2015 American Academy of Dental Sleep Medicine guidelines suggest that oral appliances may be considered an appropriate adjunct for the treatment of severe OSA [16], but the role of MADs in reducing the severity of positional OSAS remains unclear. The efficacy of MADs is lower than CPAP, but oral appliances have a similar efficacy, with a self-reported compliance rate of about 80%, and are usually preferred over CPAP [25]. Therefore, the aim of this case report was to describe the beneficial effects of a mandibular advancement device in a patient with severe positional OSAS (POSAS).

2. Case Report

A 63-year-old Caucasian male patient (body mass index: 26.1 kg/m²; professional title: neurologist) reported repeated episodes of daytime sleepiness, heavy snoring, and suspicious sleep apnea episodes. After a drug-induced sedation endoscopy (DISE), the results showed predominantly retrolingual upper airway obstruction, raising suspicion of a severe form of OSAS.

On polysomnographic (PSG) examination, the patient showed a higher AHI in the supine position (87.3/h) than in the lateral position (35.8/h), an oxygen desaturation index (ODI) of 20.4/h, and a snoring duration of 26.6% during the night. Evaluation of sleep positions revealed the patient spent most of the observed period (69.3%) in the non-supine position, whereas he was supine only 30% of the time. During the rest of the time (less than 1%), he constantly changed his position. Based on these observations, the diagnosis of severe OSAS was confirmed, and given the positional dependence, CPAP therapy was considered as the initial treatment, but the patient immediately refused it. Therefore, a MAD was inserted with a protruding mandibular displacement of 4.7 mm (Figure 1), and the anterior articulation system allowed the patient to open and move the teeth laterally to reduce potential discomfort.

No short- or long-term side effects were noted at follow-up, and compliance remained high. After two years, the PSG showed a significant decrease in all measurements. Thus, AHI reached a value of 14.7/h in the lateral position and of 21.4/h in the supine position, indicating a decrease of 58.9% in the lateral position and of 75.5% in the supine position. ODI decreased from 20.4/h before treatment to 12.1/h post-treatment. The patient also changed his usual sleeping positions: time in the supine position increased to 59.6%, while time in the lateral position decreased to 40.4%. The initial symptom of discomfort disappeared completely (Figure 2), and the reevaluation of OSAS indicated a decrease in severity from severe to mild. Overall, the patient reported a significant improvement in his quality of life.

3. Discussion

The mandibular advancement device (MAD) can be used as first-line therapy in patients with mild-to-moderate OSAS [26] without severe cardiovascular comorbidity and for severe OSA when CPAP treatment fails or is refused by the patient [27]. This case report describes the beneficial effects of MADs in an elderly, non-obese patient with severe positional OSAS who refused CPAP treatment.

In the scientific literature, the MAD shows significantly better treatment outcomes in patients with positional OSAS compared to patients with non-positional OSAS, but it does not offer a reduction in the severity of OSAS. This may be due to the unchanged or absent pharyngeal collapsibility in POSAS patients, which allows improved AHI in the supine position but without reducing OSAS symptomatology [28]. In 2004, in a study conducted on a large sample of 263 patients undergoing PSG with and without MADs, Marklund et al. demonstrated that the odds ratio for MAD treatment success was six times higher in patients with positional OSAS than in patients not treated with MADs [29]. The beneficial effect of MADs was also demonstrated in a study by Lee et al., who found that patients with POSAS had significantly better treatment outcomes (77.5% success rate) than patients with non-positional OSAS (60.0% success rate) when treatment success was defined as AHI less than 20. In the same study, the authors reported a complete reduction in obstructive events (AHI less than 10) of 57.5% in POSAS patients versus 30.0% in patients without POSAS [30]. Isono et al. demonstrated that mandibular advancement in non-obese patients increases the retropalatal airway space, whereas mandibular advancement in obese patients does not ensure upper airway patency [31].

In our case report, the clinical and PSG results obtained after a two-year follow-up period in the treatment of severe positional OSAS with a MAD showed a significant decrease in the severity of OSAS. Indeed, a 4.7 mm advancement of the mandible, a 58.9% reduction in AHI in the lateral position, a 75.5% reduction in the supine position, and a reduction in the severity of OSAS from severe to mild were observed.

The significant reduction in the severity of OSAS represents an important novelty for treatment with MADs. Since the patient in our case had a normal weight from the beginning to the end of the follow-up, the efficacy of the MAD was not affected by changes in body composition, so the achieved mandibular displacement should have allowed the patient to change his sleep position. This change in position could be related to the change in upper airway configuration caused by the advancement of the mandible, which is strongly influenced by the extent of its change in response to the change in body position, which could be exacerbated by gravity [32]. Considering that the mechanism of action of MADs is to maintain the upper airway not only by increasing the retropalatal and retrolingual spaces but also by decreasing pharyngeal collapsibility [33], we can hypothesize that the advantage in maintaining the upper airway may have determined an indirect stimulus for adopting a better and adapted position during sleep.

In this case report, the patient complied during the two-year follow-up period, and no signs or symptoms related to the side effects of the MAD occurred. According to Phillips et al., who compared the effects of CPAP and MAD therapies for OSAS in the short term (1 month), compliance was higher with MADs, demonstrating significant improvements in sleepiness, driving simulator performance, and disease-specific quality of life [34]. In a recent systematic literature review, Schwartz et al. showed that compliance was higher with MADs than with CPAP [35]. Oral devices tend to be better tolerated by patients because they are less uncomfortable. Several clinical trials have also shown that compliance is higher with MADs than with CPAP in the long term. These data are extremely important because they underscore the efficacy of oral devices in the treatment of OSAS, which, by definition, works over a longer period of time and depends on patient compliance [36]. The treatment of OSAS requires a high degree of patient compliance. Therapeutic devices (MAD or CPAP) are not only curative but are part of the maintenance phase, which can last indefinitely, and they must thus be worn every night. Unfortunately, some patients discontinue treatment almost immediately while others continue for years. We recommend that physicians consider which type of device is best accepted by patients, which increases compliance and motivates patients to continue treatment. In other words, if patients abandon one treatment option, another should be offered so that the patient still remains on treatment. The therapist plays a critical role in making the device as easy to use and adjust as possible. It is important to educate the patient that the use of the device may alter occlusion due to the movement of the teeth.

The condition of edentulous patients requires a more complicated treatment because they have a significant loss of vertical dimension and thus a less stable neuromuscular intraoral environment. As for sleep apnea, the use of a prosthesis does not seem to affect apnea, and a MAD can be placed over the prosthesis in patients with sleep apnea. However, in edentulous patients with sleep apnea, a complete prosthesis (denture) may not be stable enough to support a MAD [37]. In these cases, implants may be useful to support both the prosthesis and the MAD [38]. In a case report describing the treatment course in an edentulous patient with moderate OSA who was implanted with a complete maxillary and mandibular prosthesis, a significant improvement in the AHI score was observed without any temporomandibular joint dysfunction or masticatory muscle discomfort. After implanting maxillary and mandibular prostheses, clinicians used a MAD along with elastic button hooks to allow advancement of the mandible to increase airflow space, but without increasing the vertical dimension of occlusion [39]. In a series of six edentulous patients with mild to moderate OSAS treated with endosseous implant-supported MADs, Hoekema et al. demonstrated improvement in AHI and SaO₂ levels in five patients by the end of follow-up and reduction in OSA severity (AHI < 5) in four patients, with all patients demonstrating good compliance and low incidence of side effects or symptoms [40].

The main limitation of this work is its study design, which is based on a case report. Nevertheless, this study should be considered important evidence that even severe OSAS can be treated with a MAD in selected patients. Although it may take some time to achieve optimal results, the MAD is certainly a more acceptable device than CPAP and ensures greater treatment compliance.

4. Conclusions

Oral devices such as MADs have shown similar efficacy to CPAP in mild to moderate OSAS. Currently, data in the literature suggest that for severe OSAS, the use of CPAP is still the treatment of choice. However, CPAP therapy suffers from poor compliance and is poorly tolerated by patients. Oral appliances are not always effective in the treatment of OSAS, and anatomic and non-anatomic factors should be considered. CPAP treatment should be preferred in certain cases. In the present study, the patient did not have a high BMI, and the syndrome was mainly due to retrolingual upper airway obstruction. PSG performed 2 years after initiation of therapy with the MAD showed a 58.9% decrease in AHI in the lateral position (from 35.8/h to 14.7/h) and a 75.5% decrease in the supine position (from 87.3/h to 21.4/h). Therefore, the use of MADs may be considered a suitable alternative to CPAP. Future studies are needed to evaluate the efficacy of MADs in severe OSAS, taking into account the effects of motivation and treatment adherence, along with the reduction in severity of the condition.