Aveo Tongue Stabilizing Device For Treatment of Obstructive Sleep Apnea BY AHMAD YOUNES Professor of Thoracic Medicine Mansoura Faculty of Medicine

Introduction: Although CPAP provides the most widely used method to treat sleep disordered breathing today, it is also the most cumbersome one. Many patients find it unappealing, difficult to tolerate and unacceptably arise from outside the body. The only other non invasive alternative which can produce favorable results within a short time is oral appliance. Hoffstein Sleep Breath 2007; 11: 1-22.

Oral appliances are a simpler alternative to CPAP for the treatment of OSA as they are quiet, portable and don not require a power source Cistulli et al Sleep Med Rev 2004;8,6: oral appliance can be regarded as being either mandibular advancement splint (MAS) or tongue retaing device (TRD). MAS generally attach to the dental arches and mechanically protrude the mandible. TRD use suction pressure to maintain the tongue in a protruded position during sleep. MAS therefore require the patient to have sufficient teeth whereas TRD can be used by edentulous patients Ferguson et al. Sleep 2006; 29(2):

The American Academy of Sleep Medicine recommended the use of oral appliances for mild to moderate OSA or patients with severe OSA who are unable to tolerate CPAP or refuse treatment with CPAP. There is reboust evidence of the efficacy of oral appliances both in regard to improvement of polysomnographic indices as well as modifying the health risk associated with OSA Ferguson et al. Sleep 2006; 29(2):

Aims of this work: The aims of this work were to evaluate the efficacy and complications of Aveo-tongue stabilizing device in the treatment of OSA and to determine the predictors of its success.

Subjects and methods: The inclusion criteria of the cases of this study were at least two symptoms of OSA (snoring, fragmented sleep, witnessed apneas, morning headache and daytime sleepiness) and evidence of OSA on PSG (AHI  5/hour) Exclusion criteria include severe OSA (AHI > 30/hour), bruxism, central apneas, regular use of sedatives, exaggerated gag reflex and standard contraindications for magnetic resonance imaging (MRI) such as cardiac defibrillators and metallic prothesis.

From twenty patients who commenced the trial, 15 patients completed the study (2 patients refused the device and 3 patients dropped during follow up). For the remaining fifteen patients, the following were done: Thorough history taking with stress on symptoms of OSA. Physical examination with stress on neck circumference, body mass index (BMI), and upper airway examination to exclude space occupying lesions in the nose and mouth and dental examination (teeth and gum).

Full night PSG for objective diagnosis of OSA and repeated later on after 1 month of acclimatization of the patients on the device for assessment of response to appliance. Positional OSA means >50% of AHI occur in supine position. Consultation with the Prosthodontic Department, Mansoura Faculty of Dentistry, was done for proper insertion of the TRD device intra-orally.

The TRD used in this study was a preformed,non adjustable appliance. Aveo-tongue stabilizing device made by Innovative Health Technology PO Box Chritchurch, New Zeland.

Intra-oral examination was made to exclude any local inflammatory causes which prevent placement of the device, so thorough examination was performed and the prosthodontist learned the patients how to insert and remove the device intra-orally and instruct the patient for the way for maintaining the proper oral hygiene measures and hygiene measures of the device. Follow up program for all the patients was performed during the period of study every week.

MRI was done on the upper airways with assessment of the shortest retro-palatal and retro-glossal dimensions (Antero-posterior and lateral) with and without wearing the device while the patients were awake in supine position. A mid saggital slice was done first and from which the shortest retro-palatal and retro-glossal trans-axial slices were chosen for calculation of antero-posterior and lateral dimensions.

Response to the device (symptoms of OSA especially Epworth sleepiness scale (ESS) and results of PSG while wearing the device were assessed after 1 month of use of the device. Complete success means reduction of AHI to a level of normal(< 5 events / hour). Partial success means > 50% reduction in AHI but the residual AHI > 5 events / hours. Treatment failure means < 50% reduction in AHI Chan et al Chest 2007; 132: Assessment of complications and compliance were done after 1 month of wearing the device.

Results

This prospective study comprised 15 patients with mild to moderate OSA. The mean age was 36 ± 3.3 years, 60% (9 out of 15) were males and 40% (6 out of 15) were females, the mean BMI was 29.8 ± 1.9 and mean neck circumference was 40.2 ± 2.8 cm.

Table (1): Symptoms of studied cases of OSA without and with use of the oral appliance Statistics with oral appliance without oral appliance Symptoms P valueZ%No% 0.002* 0.003* 0.005* 0.025* 0.046* )Snoring 2) Daytime sleepiness 3) Morning headache 4) Nocturnal choking 5) Witnessed apnea

Table (2): ESS of studied cases of OSA without and With use of oral appliance. Statistics Mean ± SD t = P < * ± ± 1.84 ESS without oral appliance ESS with oral appliance ESS Epworth sleepiness scale

Table (3): PSG parameters in studied cases of OSA without and with oral appliance. Statistics With oral appliance Mean ± SD Without oral appliance Mean ± SD PSG parameters t = P < 0.001* 14.1 ± ± 2.35(1) De-saturation index (events/hour) t = 6.96 P < 0.001* ± ± 3.89 (2) Average duration SaO2 < 90% (second) t = 6.63 P < 0.001* 85.6 ± ± 30.4(3) Minimum SaO2 % t = P < 0.001* 1.89 ± ± 0.82(4) % Total sleep time SaO2 < 90% t = P < 0.001* 9.93 ± ± 4.03(5) AHI (events/hour) t = P < 0.001* ± ± 4.06(6) Arousal index (events/hour) t = P < 0.001* 4.2 ± ± 5.99(7) % Total sleep time of snoring

Table (4): MRI of the upper airways of studied cases of OSA without and with oral appliance Statistics With oral appliance Mean ± SD Without oral appliance Mean ± SD Retro-palatal t = P < 0.001* 6.60 ± ± 0.52 (a) Antero-posterior dimension (millimeter) t = P < 0.001* 11.1 ± 1.68 ± 0.76(b) Lateral dimension (mm) t = P < ± ± 0.10(c) Antero-posterior / Lateral ratio Retro-glossal t = 14.4 P < 0.001* 13.7 ± ± 0.52(a) Antero-posterior dimension (mm) t = 11.8 P < 0.001* 23.7 ± ± 0.45(b) Lateral dimension (mm) t = P < 0.001* 0.58 ± ± 0.02(c) Antero-posterior / Lateral ratio

Table (5): Outcome of aveo-tongue stabilizing device in patients with OSA %No Complete success Partial success Treatment failure 10015Total

Table (6): predictors of success in studied cases of OSA with oral appliance Statistics Failure (6) Mean ± SD Success (9) Mean ± SD t = P = ± ± 3.39Age t = P <0.001 * ± ± 1.05Neck circumference t = P = 0.002* ± ± 1.36BMI t = P = ± ± 0.67ESS t = P = ± ± 0.93Basal SaO2 t = P = 0.002* 3.57 ± ± 0.61% Total sleep time SaO2 < 90% t = P <0.001* ± ± 1.73AHI t = p = ± ± 3.48Arousal index t = P = ± ± 7.05% Total sleep time snoring

Table (7): Effect of positional OSA on outcome of oral appliance Statistics Predominant supine AHI (7) Predominant Side AHI (8)  2 = P = * 7 (100%) 0 (0%) 2 (25%) 6 (75%) Success (9) Failure (6)

Table (8): Compliance of use of aveo tongue stabilizing device in patients with OSA %No Compliant Non compliant 10015Total

Table (9): Complications of Aveo tongue stabilizing device in patients with OSA %No Excessive salivation Oral dryness Tongue abrasion Jaw pain

The limitations of this study include The MRI imaging of the upper airway were done for patients during wakfullness which differ from the physiologic state of sleep Relatively small number of studied cases short duration of follow up.

Conclusions Aveo TRD was effective in treatment of 60% of mild to moderate OSA and side effects occurred frequently to the extent to prevent 40% of patients to stop use of the device. The predictors of success were cases with low BMI, small neck circumference, low AHI and less hypoxemia and predominant supine AHI.