Contemporary surgery for obstructive sleep apnea syndrome

Controversies in Sleep Apnea

This chapter discusses controversies in diagnosis and management of obstructive sleep apnea (OSA), with particular focus on surgical management to improve quality of life. Though OSA is a complex disorder that affects millions of people worldwide, its management remains controversial among clinicians. Gaps in understanding its pathophysiology, long-term health consequences, diagnostic methods, and treatment strategies exist. While continuous positive airway pressure (CPAP) therapy is considered the gold standard for moderate to severe obstructive sleep apnea (OSA), its adherence rate is often low, and its efficacy in improving outcomes beyond symptom reduction and quality of life improvement is uncertain. As such, surgical intervention may be an alternative for specific patient populations. Additionally, the type of surgical intervention may depend on individual patient needs, anatomic features, as well as preferences.

Genioglossus Advancement: Technique Modification for Improved Chin Contour

Genioglossus advancement plays an important role in the armamentarium of the obstructive sleep apnea surgeon and has gone through many iterations over several decades. A recently described technique involves creating a box osteotomy, which is carried through the inferior border of the mandible in order to increase recruitment of the suprahyoid musculature. Here we introduce a further modification of the technique that uses virtual planning to improve the safety and accuracy of genial tubercle capture. In addition, angulation of the lateral osteotomies enhances bone to bone contact. Before the osteotomy, the surgeon has the opportunity to drill the buccal plate to reduce the chin profile. This approach is particularly valuable in the patient who is prognathic at baseline or who becomes prognathic after simultaneous maxillomandibular advancement. Here we discuss this unique approach, demonstrating how the patient profile may be balanced even as the genial tubercle is advanced.

[Role of Robotic Surgery in ENT]

Since the beginning of the 21^st century, surgical robots have been used in the ENT-environment. They primarily support surgeons in minimal invasive transoral operations, especially in multidisciplinary treatment concepts of head and neck tumors, but also in snoring surgery the robot provides a complement to the established transoral laser surgery. In the meantime there is a large number of data that deals with the importance of oncological results, function maintenance, economics and future perspectives.Operation areas of the current robot devices are still limited in the ENT-environment. As the number of cases are small, efforts are being made to connect centres on a national and international level. Thus, uniform training standards, targeted knowledge and data exchange as well as further development of systems would be managed better. The creation of small and agile ENT-specific equipment could expand the possibilities as a next step for the future and finally lead to a wide scale of ENT-surgical applications.

The Jaw Epidemic: Recognition, Origins, Cures, and Prevention

Contemporary humans are living very different lives from those of their ancestors, and some of the changes have had serious consequences for health. Multiple chronic "diseases of civilization," such as cardiovascular problems, cancers, ADHD, and dementias are prevalent, increasing morbidity rates. Stress, including the disruption of traditional sleep patterns by modern lifestyles, plays a prominent role in the etiology of these diseases, including obstructive sleep apnea. Surprisingly, jaw shrinkage since the agricultural revolution, leading to an epidemic of crooked teeth, a lack of adequate space for the last molars (wisdom teeth), and constricted airways, is a major cause of sleep-related stress. Despite claims that the cause of this jaw epidemic is somehow genetic, the speed with which human jaws have changed, especially in the last few centuries, is much too fast to be evolutionary. Correlation in time and space strongly suggests the symptoms are phenotypic responses to a vast natural experiment-rapid and dramatic modifications of human physical and cultural environments. The agricultural and industrial revolutions have produced smaller jaws and less-toned muscles of the face and oropharynx, which contribute to the serious health problems mentioned above. The mechanism of change, research and clinical trials suggest, lies in orofacial posture, the way people now hold their jaws when not voluntarily moving them in speaking or eating and especially when sleeping. The critical resting oral posture has been disrupted in societies no longer hunting and gathering. Virtually all aspects of how modern people function and rest are radically different from those of our ancestors. We also briefly discuss treatment of jaw symptoms and possible clinical cures for individuals, as well as changes in society that might lead to better care and, ultimately, prevention.

miR-126a-3p targets HIF-1α and alleviates obstructive sleep apnea syndrome with hypertension

The obstructive sleep apnea syndrome (OSAS) is a common sleep-related breathing disorder and an important cause of refractory hypertension. MicroRNAs (miRNAs) are involved in the development of hypertension, but their role in OSAS with hypertension (OSAS-hypertension) has been little studied. Evidence indicates that miR-126a-3p expression is lower in patients with OSAS-hypertension compared with the patients with OSAS alone. However, its role in the pathogenesis of OSAS-hypertension remains unclear. Therefore, this study aims to investigate the role of miR-126a-3p in OSAS-hypertension and to determine whether HIF-1α is involved in this process. Sprague Dawley rats were exposed to chronic intermittent hypoxia (CIH) for 8 weeks to induce OSAS-hypertension. Rat aortic smooth muscle cells (A7r5) were cultured under hypoxia as an in vitro model. Our results showed that rats exposed to 8 week CIH exhibited decreased miR-126a-3p and increased HIF-1α expression. Furthermore, administration of recombinant adeno-associated virus expressing miR-126a-3p (rAAV-miR-126a) counteracted the CIH-induced systolic blood pressure upregulation, oxidase stress, inflammation, and heart and abdominal aorta vascular remodeling. Moreover, the mechanism was associated with its targeted suppression of HIF-1α. These findings suggest that miR-126a-3p might be a novel potential therapeutic target for the treatment of OSAS-hypertension.

Maxillomandibular Advancement and Upper Airway Stimulation: Extrapharyngeal Surgery for Obstructive Sleep Apnea

There are many ways to categorize surgery for obstructive sleep apnea (OSA), one of which is to distinguish between intrapharyngeal and extrapharyngeal procedures. While the general otolaryngologist treating OSA is familiar with intrapharyngeal procedures, such as uvulopalatopharyngoplasty and tongue base reduction, extrapharyngeal sleep operations such as maxillomandibular advancement (MMA) and upper airway stimulation (UAS) have evolved rapidly in the recent decade and deserve a dedicated review. MMA and UAS have both shown predictable high success rates with low morbidity. Each approach has unique strengths and limitations, and for the most complex of OSA patients, the two in combination complement each other. Extrapharyngeal airway operations are critical for achieving favorable outcomes for sleep surgeons.

Strategy for Optimizing Airway Volume With Genioglossal Advancement Using Cutting Guide in the Treatment of Obstructive Sleep Apnea

The genioglossus advancement muscle is a technique used to treat obstructive sleep apnea and depends on the precise location of the muscle insertion into the geniotubercle. The aim of this article was to present a case report about a 38-year-old male patient with obstructive sleep apnea even after undergoing uvulopalatopharyngoplasty and mentoplasty. A maxillo-mandibular advancement and genioglossus was proposed, for this a virtual planning of the surgical guide was done using a specialized software. The great advantage is to reduce the osteotomy by focusing precisely on the insertion of the muscle. The cutting guide facilitated the surgical procedure in all aspects and brought safety.

Efficiency of Expansion Sphincter Pharyngoplasty in the Treatment of Obstructive Sleep Apnea Syndrome

Objective

Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent episodes of upper respiratory-tract obstruction during sleep and decrease in arterial oxygen saturation. Expansion sphincter pharyngoplasty (ESP) is a simple, safe, and effective method for the surgical treatment of OSAS. The aim of our study was to evaluate the efficacy of ESP with polysomnography (PSG) in OSAS patients.

Methods

This study was conducted on patients referred to our center for the treatment of snoring, apnea, witnessed apnea, and daytime sleepiness during 2010-2018. Overall, 67 patients (16 females, 51 males) who had PSG test at postoperative three months and were considered suitable with history, physical examination, and surgery after PSG were included in the study. Patients were classified into three groups according to OSAS severity: mild, moderate, and severe. Patient age, sex, body mass index (BMI), pre- and postoperative period apnea-hypopnea index (AHI), Epworth sleepiness scores, and PSG data were recorded.

Results

The mean BMI of all groups was 27.44±2.73. The postoperative AHI decreased from 18.26±2.23 to 8.01±0.97 (p<0.001). Surgical success rate was 67.2%; it was higher in females (p=0.047). The highest success rate was found in the mild OSAS group; however, this difference was not statistically significant when compared to the other groups (p=0.217). There were statistically significant improvement at postoperative Epworth sleepiness scores and minimum O₂ saturations (p<0.001 and p=0.018, respectively).

Conclusion

ESP is an effective and successful surgery in selected patients with lateral pharyngeal and retropalatal narrowing.

Imaging of adult obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is characterised by recurrent upper airway collapse during sleep resulting in chronic and repetitive hypoxia, hypercapnia, subsequent arousal and fragmented sleep. Symptoms are insidious and diagnosis is usually delayed. Moderate to severe OSA has serious health implications with significant increase in all causes of mortality in patients with the condition as compared with unaffected individuals. The prevalence of OSA in the 30-70 year age group is estimated at 27% of males and 11% of females and it increases with age. 80% of affected individuals are obese and as obesity rates rise, so has the prevalence of OSA. An overnight polysomnogram (PSG) is required for a definitive diagnosis of OSA. Imaging has played a fundamental role in the evaluation of the anatomical factors associated with recurrent upper airway collapse and the pathogenesis of OSA. The upper airway is frequently imaged by radiologists, providing an opportunity to detect features that are strongly associated with unsuspected OSA and to raise the possibility of this diagnosis. The gold standard of treatment is continuous positive airway pressure (CPAP) which acts as a pneumatic splint for the upper airway. However, efficacy is frequently limited by poor tolerance; clinicians and patients are increasingly opting for one of a range of surgical procedures. Dedicated imaging protocols can be performed for evaluation of the upper airway to aid surgical planning.

Modified Genioglossal Advancement for Isolated Treatment of Obstructive Sleep Apnea

INTRODUCTION

Genioglossal advancement is a surgical procedure for obstructive sleep apnea (OSA) that has lost favor as a primary treatment strategy. The authors describe utilization of a modified genioglossal advancement (MGA), combining a geniotubercle advancement via sliding genioplasty and a glossopexy.

METHODS

A retrospective review was performed. Preoperative and postoperative apnea-hypopnea indices (AHIs) were compared to determine OSA treatment success.

RESULTS

Five patients underwent MGA. Three subjects had preoperative and postoperative AHI scores which improved from 61, 28, and 19 (mean = 36) to 4.5, 2, and 6.3 (mean = 4.3), respectively. Two subjects had incomplete data for comparison. All subjects had an acceptable esthetic outcome.

DISCUSSION

In properly selected subjects, MGA can alleviate OSA and provide improved esthetic outcomes.

Predicting Outcomes after Uvulopalatopharyngoplasty for Adult Obstructive Sleep Apnea

Objective

Uvulopalatopharyngoplasty (UPPP) remains one of the most common surgical treatments for patients with obstructive sleep apnea. However, the results after UPPP are unpredictable. The purpose of this meta-analysis is to identify predictors of success after UPPP.

Data Sources

A literature search was performed utilizing PubMed, EMBASE, SCOPUS, and the Cochrane Library.

Review Methods

The keywords and medical subject heading terms used were uvulopalatopharyngoplasty and UPPP. Studies were included if UPPP was used as a single surgical procedure for the treatment of obstructive sleep apnea and results were presented separately as responder (surgical success) and nonresponder (surgical failure). Exclusion criteria included pediatric patients and other surgical procedures (eg, nasal and hypopharyngeal) performed at the same time as the UPPP. Age, body mass index, preoperative apnea-hypopnea index, Friedman stage, and several cephalometric variables were compared between responders and nonresponders.

Results

A total of 1257 studies were screened, with 15 studies included in this meta-analysis. Our results demonstrate that Friedman stage I is a strong predictor for success after UPPP, while Friedman stage III and low hyoid position are negative predictors. Age, body mass index, preoperative apnea-hypopnea index, and other cephalometric measurements were not significant.

Conclusion

Friedman stage and hyoid position are important predictors for UPPP.

Surgical Management of Obstructive Sleep Apnea

Surgical management of snoring and obstructive sleep apnea is indicated when a surgically correctable abnormality is believed to be the source of the problem. Many patients opt for surgical treatment after noninvasive forms of treatment have been proven ineffective or difficult to tolerate. With increasing frequency, functional rhinoplasty, septoplasty, turbinoplasty, palatal surgery, and orthognathic surgery are being used in the management of snoring and obstructive sleep apnea. Plastic surgeons' experience with aesthetic nasal surgery, nasal reconstruction, palatal surgery, and craniofacial surgery puts them at the forefront of performing surgery for snoring and sleep apnea. The role of functional septorhinoplasty, turbinoplasty, palatal surgery, genioglossal advancement, and orthognathic surgery is indispensable in the surgical management of obstructive sleep apnea. Multidisciplinary management of these patients is critical, and plastic surgeons are encouraged to work collaboratively with sleep medicine clinicians and centers.

The status of cephalometry in the prediction of non-CPAP treatment outcome in obstructive sleep apnea patients

Obstructive sleep apnea syndrome (OSAS) is the most common sleep disordered breathing disorder (SDB) in adults and is characterized by a recurrent partial or complete collapse of the upper airway during sleep. This can be caused by many factors, sometimes interacting, such as skeletal malformations, soft tissue crowding, respiratory instability and the various effects of aging, obesity and gender that dictate craniofacial and upper airway anatomy. Research has demonstrated that the majority of patients exhibit at least one anatomical component such as retrognathia or a narrow posterior airway space that predisposes to the development of OSAS. Within the predisposing elements for OSAS many seem to point to anatomical characteristics. A standardized and relatively simple radiologic technique to evaluate anatomical craniofacial relationships is cephalometry. This has been used already for a long time in orthodontics, but is now gradually being introduced in OSAS treatment to envisage optimal treatment selection as well as to predict treatment outcomes. The purpose of the present review is to evaluate the contribution of cephalometry in the prediction of outcomes from OSAS treatments that depend on the upper airway morphology in their mechanisms of action such as oral appliances that advance the mandible as well as various surgical methods. In addition, an overview of imaging modalities and methods that currently are being used in cephalometric analysis in OSAS patients is provided. The findings indicate that isolated cephalometric parameters cannot be used to reliably predict treatment outcomes from mandibular advancement devices and surgical methods for OSAS. Extreme or outlying values of cephalometric parameters may rather be used as contra-indicators or 'red flags' instead of predictors.

Transoral robotic lingual tonsillectomy in adults: preliminary results

CONCLUSION

Hypertrophy of lingual tonsils can be safely and effectively managed by transoral robotic surgery via a minimally invasive approach. The operating costs can be relatively high although the advantages to patients seem to justify the procedure. Transoral robotic surgery can represent the definitive treatment in hypertrophy of the lingual tonsils.

OBJECTIVE

The purpose of this work was to assess the feasibility, safety, and outcomes of transoral robotic surgery for lingual tonsillar hypertrophy in adults with obstructive sleep apnea.

METHODS

Retrospective medical records of six patients who underwent tongue base resection using the da Vinci Surgical Robotic System from September, 2012 through December, 2013 in a tertiary care hospital were evaluated. Demographic data, preoperative and postoperative polysomnography and Epworth Sleepiness Scale (ESS) scores, robot docking time, operative and postoperative aspects including surgical time, amount of bleeding, and early and late complications were collected and analyzed.

RESULTS

All patients successfully underwent lingual tonsillectomy using the da Vinci Surgical system. Transnasal endotracheal entubation was performed in all patients and they were all extubated before leaving the operation room. No tracheotomies were performed perioperatively for airway management. The patients were discharged on the fifth postoperative day. Operative time, estimated blood loss, and postoperative complication profiles were within the expected and acceptable limits for lingual tonsillectomy. There was a statistically significant decrease in apnea hypopnea index (AHI) (mean AHI from 27.5 to 6.3) and ESS scores (from 14.1 to 7.1).

An observational cohort study of the effects of septoplasty with or without inferior turbinate reduction in patients with obstructive sleep apnea

BACKGROUND

The objective of this observational study was to evaluate the outcomes of intranasal surgery in patients with obstructive sleep apnea (OSA) in a single institution in Norway.

METHODS

Fifty-nine patients with OSA and clinically significant nasal obstruction underwent either septoplasty alone or septoplasty with concomitant volume reduction of the turbinates from August 2008 until the end of December 2010. Subjects were scheduled for sleep polygraphy before and 3 months after treatment. In this observational single-centre cohort study we evaluated and compared the effect of these two specific surgical procedures on sleep related parameters.

RESULTS

There was a significant reduction in the apnea-hypopnea index (AHI) only in the group that had septoplasty with turbinate reduction (17.4, (SD 14.4) - 11.7, (SD 8.2), p <0.01), and this effect was significantly better than in the group treated with septoplasty alone. Other objective parameters remained unchanged. Subjective assessments obtained with a postoperative questionnaire showed an equally positive effect on diurnal sleepiness and nasal obstruction in both groups, and a better effect on sleep quality in the combined treatment group.

CONCLUSION

The effect of nasal surgery on obstructive sleep apnea seemed to be greater when there were indications for combined surgery of the inferior turbinates and the nasal septum, compared to when there were indications for septoplasty alone.

Palatal implants for persistent snoring and mild obstructive sleep apnea after laser-assisted uvulopalatoplasty

Laser-assisted uvulopalatoplasty (LAUP) was widely performed in 1990s as a surgical therapeutic procedure to improve snoring or mild obstructive sleep apnea (OSA). However, LAUP is not currently recommended as a treatment for OSA because the evidence for its efficacy is insufficient. Little is known about alternative minimally invasive surgery in patients who refuse continuous positive airway pressure or oral appliance after failed LAUP. We present a case of successful surgical treatment of persistent snoring and mild OSA with palatal implants after LAUP. This case suggests that palatal implants may be offered as an alternative surgical procedure for selective patients with persistent or recurrent snoring or mild OSA after LAUP.

Effect of isolated uvulopalatopharyngoplasty on subjective obstructive sleep apnea symptoms

OBJECTIVES

The aims of this study were 1) to evaluate the effect of isolated uvulopalatopharyngoplasty (UPPP) on subjective obstructive sleep apnea (OSA) symptoms in adult patients regardless of the response to surgery, and ultimately 2) to investigate the differences in changes in subjective OSA symptoms between successful and unsuccessful surgery groups.

METHODS

Twenty consecutive adult patients who underwent isolated UPPP were enrolled. Pre- and postoperative subjective OSA symptoms (snoring, witnessed apnea, daytime sleepiness, morning headache, daytime fatigue, restless sleep, difficulty with morning arousal) and polysomnographic data were evaluated in all subjects. Changes in subjective OSA symptoms before and after surgery were investigated in the successful (n=11) and unsuccessful (n=9) groups. Surgical success was defined as a reduction of at least 50% in the preoperative apnea-hypopnea index (AHI) and a postoperative AHI less than 20 per hour.

RESULTS

After isolated UPPP, all subjective OSA symptoms changed significantly in the patients, especially in the successful group. In the unsuccessful group, snoring, witnessed apnea and daytime fatigue changed significantly, while other symptoms did not change significantly after surgery.

CONCLUSION

Isolated UPPP may improve subjective OSA symptoms in adult patients whom surgery was successful or unsuccessful. However, after isolated UPPP, the improvements in subjective OSA symptoms in the unsuccessful group may be different from those in the successful group.

Optimal level of continuous positive airway pressure: auto-adjusting titration versus titration with a predictive equation

OBJECTIVES

The aims of the present study were twofold. We sought to compare two methods of titrating the level of continuous positive airway pressure (CPAP) - auto-adjusting titration and titration using a predictive equation - with full-night manual titration used as the benchmark. We also investigated the reliability of the two methods in patients with obstructive sleep apnea syndrome (OSAS).

METHODS

Twenty consecutive adult patients with OSAS who had successful, full-night manual and auto-adjusting CPAP titration participated in this study. The titration pressure level was calculated with a previously developed predictive equation based on body mass index and apnea-hypopnea index.

RESULTS

The mean titration pressure levels obtained with the manual, auto-adjusting, and predictive equation methods were 9.0 +/- 3.6, 9.4 +/- 3.0, and 8.1 +/- 1.6 cm H2O,respectively. There was a significant difference in the concordance within the range of +/- 2 cm H2O (p = 0.019) between both the auto-adjusting titration and the titration using the predictive equation compared to the full-night manual titration. However, there was no significant difference in the concordance within the range of +/- 1 cm H2O (p > 0.999).

CONCLUSIONS

When compared to full-night manual titration as the standard method, auto-adjusting titration appears to be more reliable than using a predictive equation for determining the optimal CPAP level in patients with OSAS.

CPAP therapy prevents increase in blood pressure after upper airway surgery for obstructive sleep apnoea

OBJECTIVE

The aim of this study was to investigate the efficacy of continuous positive airway pressure (CPAP) therapy following uvulopalatopharyngoplasty (UPPP) to prevent blood pressure (BP) elevation during sleep.

METHODS

Sixteen normotensive patients with OSA were subjected to UPPP with or without septoplasty. These patients were instrumented for 24 h of ambulatory BP recording, polysomnography, nocturnal urinary catecholamine and pain evaluation using a visual analogue scale in the day prior to surgery (D-1), following the surgery (D+1) and 30 days later (D+30). For the D+1, the patients were divided into two groups: the without CPAP therapy group and the with CPAP therapy group.

RESULTS

The apnoea-hypopnoea index (AHI) significantly increased in the patients without CPAP therapy compared with the D-1 (74 ± 23 vs. 35 ± 6 times/h, p < 0.05), and in the CPAP group, there was a significant reduction in the average AHI value to 14 ± 6 times/h, p < 0.01. During D+1, we observed an increase in the nocturnal systolic BP (10 %), diastolic BP (12 %) and heart rate (14 %) in the group without CPAP. These metrics were re-established in the CPAP group to values that were similar to those that were observed on the D-1. The absence of nocturnal dipping in the group without CPAP was followed by a significant increase in nocturnal norepinephrine (42 ± 12 μg/l/12 h) and epinephrine (8 ± 2 μg/l/12 h) levels compared with the D-1 (norepinephrine 17 ± 3; epinephrine 2 ± 0.3 μg/l/12 h, p < 0.001). In the patients who used the CPAP treatment, the nocturnal catecholamine levels were similar to D-1. The effectiveness of intravenous analgesic therapy was verified by a significant decrease in the pain scores in patients both with and without CPAP therapy.

CONCLUSION

These data confirm an increase in the AHI on the night following UPPP with or without septoplasty. This increase promotes an absence of nocturnal dipping and a significant increase in urinary catecholamine levels. CPAP therapy was effective to prevent the transitory increase in BP.

Selected surgical managements in snoring and obstructive sleep apnea patients

BACKGROUND

The diagnostic process and the surgical procedures in patients with snoring and obstructive sleep apnea syndrome (OSAS) are crucial. The aim of this study was to assess the efficacy of surgical treatment in snoring and OSAS patients.

MATERIAL/METHODS

A precise laryngological examination and screening polysomnography (Poly-Mesam) were performed in all patients with mild, moderate and severe OSAS before and 6 months after surgery. The patients completed questionnaires concerning their complaints. We included patients qualified to septoplasty, laser-assisted uvulopalatoplasty (LAUP), uvulopalatopharyngoplasty (UPPP) and radiofrequency-induced thermotherapy of the tongue base (RITT). Outcome evaluation of surgery was performed on the basis of data received from follow-up laryngological examinations, selected parameters obtained from the Poly-Mesam test and follow-up questionnaires.

RESULTS

In most cases we observed improvement, defined as decreasing some sleep parameters, such as a respiratory disturbance index (RDI), by more than 50%, decreasing the loudness of snoring, decreasing the number of hypopneas, and obtaining better blood saturation values. After UPPP we noticed changes in retropalatal space, soft palate dimensions and uvula-posterior pharyngeal wall distance. In the postoperative period we did not observe severe complications. In some cases we found short-lived palatal deficiency after UPPP. Patients after RITT experienced discomfort and throat pain lasting from 2 to 4 days. In 2 patients we observed swelling of the tongue base, which decreased after few days.

CONCLUSIONS

Surgery in OSAS contributes to normalization of some sleep parameters. The majority of patients experienced improvement after surgery.

Changes in lung volume and upper airway using MRI during application of nasal expiratory positive airway pressure in patients with sleep-disordered breathing

Nasal expiratory positive airway pressure (nEPAP) delivered with a disposable device (Provent, Ventus Medical) has been shown to improve sleep-disordered breathing (SDB) in some subjects. Possible mechanisms of action are 1) increased functional residual capacity (FRC), producing tracheal traction and reducing upper airway (UA) collapsibility, and 2) passive dilatation of the airway by the expiratory pressure, carrying over into inspiration. Using MRI, we estimated change in FRC and ventilation, as well as UA cross-sectional area (CSA), in awake patients breathing on and off the nEPAP device. Ten patients with SDB underwent nocturnal polysomnography and MRI with and without nEPAP. Simultaneous images of the lung and UA were obtained at 6 images/s. Image sequences were obtained during mouth and nose breathing with and without the nEPAP device. The nEPAP device produced an end-expiratory pressure of 4–17 cmH2O. End-tidal Pco2rose from 39.7 ± 5.3 to 47.1 ± 6.0 Torr ( P < 0.01). Lung volume changes were estimated from sagittal MRI of the right lung. Changes in UA CSA were calculated from transverse MRI at the level of the pharynx above the epiglottis. FRC determined by MRI was well correlated to FRC determined by N2washout ( r = 0.76, P = 0.03). nEPAP resulted in a consistent increase in FRC (46 ± 29%, P < 0.001) and decrease in ventilation (50 ± 15%, P < 0.001), with no change in respiratory frequency. UA CSA at end expiration showed a trend to increase. During wakefulness, nEPAP caused significant hyperinflation, consistent with an increase in tracheal traction and a decrease in UA collapsibility. Direct imaging effects on the UA were less consistent, but there was a trend to dilatation. Finally, we showed significant hypoventilation and rise in Pco2during use of the nEPAP device during wakefulness and sleep. Thus, at least three mechanisms of action have the potential to contribute to the therapeutic effect of nEPAP on SDB.

Effect of upper airway surgery on heart rate variability in patients with obstructive sleep apnoea syndrome

To determine whether surgery influences cardiovascular autonomic modulation in obstructive sleep apnoea syndrome (OSAS), the present study was performed to evaluate the effect of upper airway (UA) surgery on heart rate variability (HRV) using frequency domain analysis for patient groups who have had either successful or unsuccessful surgery. We compared body mass index (BMI), polysomnographic [apnoea index (AI), apnoea-hypopnoea index (AHI), minimum SaO(2)] and HRV [very low frequency (VLF) power, low frequency (LF) power, high frequency (HF) power, HF/LF ratio, LFnu = LF/(LF + HF), HFnu = HF/(LF + HF)] parameters between the unsuccessful (n = 14) and successful (n = 22) surgical groups before and after UA surgery. Significant changes were observed for the successful patient group with respect to mean AI (from 29.1 ± 21.3 to 2.0 ± 3.2 events h(-1), P < 0.001), AHI (from 38.6 ± 20.0 to 5.6 ± 5.1 events h(-1), P < 0.001), minimum SaO(2) (from 73.3 ± 12.7 to 86.3 ± 6.5%, P < 0.001), VLF power (from 25599 ± 12906 to 20014 ± 9839 ms(2), P = 0.013), LF power (from 17293 ± 7278 to 14155 ± 4980 ms(2), P = 0.016), LFnu (from 0.700 ± 0.104 to 0.646 ± 0.128, P = 0.031) and HFnu (from 0.300 ± 0.104 to 0.354 ± 0.128, P = 0.031); however, mean BMI, HF power and LF/HF ratio did not change significantly after UA surgery. No significant changes were observed in the unsuccessful surgical group. Successful UA surgery may improve cardiac sympathetic and parasympathetic modulation in patients with OSAS.

Cephalometric predictors of therapeutic response to multilevel surgery in patients with obstructive sleep apnea

PURPOSE

The present study investigated whether cephalometric measurements can predict the therapeutic efficacy of multilevel phase I surgery for patients with obstructive sleep apnea (OSA).

PATIENTS AND METHODS

Among 210 patients with OSA who underwent multilevel phase I surgery, 85 were recruited on the basis of the baseline polysomnography, body mass index, and lateral cephalogram recordings. The patients were divided into 2 groups according to the degree of change in the apnea-hypopnea index before and 6 months after multilevel surgery: good responders (>50% decrease in apnea-hypopnea index) and poor responders (0% to 50% decrease or increase in apnea-hypopnea index). Cephalometric analysis was performed to identify the relevant variables, with division into 5 compartments: craniofacial, soft palate, tongue, hyoid bone, and upper airway variables.

RESULTS

In the craniofacial compartment, poor responders represented skeletal Class II with a more retrognathic mandible, and a hyperdivergent vertical pattern with a larger mandibular plane angle, longer lower facial height, and steeper occlusal plane than good responders. In the upper airway compartment, poor responders had narrower middle and inferior airway spaces and a longer upper airway length than good responders. No significant differences were found in the soft palate, tongue, and hyoid measurements between the 2 groups.

CONCLUSION

Some preoperative cephalometric measurements were verified retrospectively to predict the therapeutic response to the multilevel surgery in patients with OSA. This study would contribute not only to establishing selective criteria for the surgical approach to patients with OSA in ear-nose-throat practice but also in deciding on the referral to orthodontists or maxillofacial surgeons.

Predictive role of nasal functionality tests in the evaluation of patients before nocturnal polysomnographic recording

Obstructive sleep apnoea syndrome is a disease characterized by a collapse of the pharyngeal airway resulting in repeated episodes of airflow cessation, oxygen desaturation, and sleep disruption. It is a common disorder affecting at least 2-4% of the adult population. The role of nasal resistance in the pathogenesis of sleep disordered breathing and sleep apnoea has not been completely clarified. Aim of the present study was to establish whether nasal resistance and nasal volumes, measured by means of Active Anterior Rhinomanometry and Acoustic Rhinometry together with Muco-Ciliary Transport time play a positive predictive role in the evaluation of Obstructive sleep apnoea syndrome patients before running a nocturnal polysomnographic recording. A retrospective study was performed analysing 223 patients referred for suspected Obstructive sleep apnoea syndrome. All patients were submitted to complete otorhinolaryngological evaluation and underwent nocturnal polysomnography. On the basis of polysomnographic data analysis, the apnoea-hypopnoea index and snoring index, patients were classified into two groups: Group 1 (110/223 patients) with a diagnosis of mild-moderate Obstructive sleep apnoea syndrome (apnoea-hypopnoea index < 30) and Group 2 (113/223 patients) affected by snoring without associated hypoxaemia/hypercapnia. A control group of 76 subjects, not complaining of sleep disorders and free from nasal symptoms was also selected. The results showed, in all the snoring and Obstructive sleep apnoea syndrome patients, total nasal resistance and increased Muco-Ciliary Transport time compared to standard values. Furthermore, the apnoea-hypopnoea index was significantly higher in patients with higher nasal resistence and significantly different between the groups. These results allow us to propose the simultaneous evaluation of nasal functions by Active Anterior Rhinomanometry, Acoustic Rhinometry, and Muco-Ciliary Transport time in the selection of patients undergoing polysomnography.

Effect of successful surgical treatment on changes of position during sleep in adults with obstructive sleep apnea syndrome

OBJECTIVES

The purpose of this study was to evaluate the changes of position during sleep as determined by polysomnography before and after upper airway surgery for obstructive sleep apnea syndrome in patients with no response to surgery ("nonresponse group") and in those who did have a response to surgery ("response group").

METHODS

We analyzed a total of 106 polysomnograms from 53 subjects and compared the preoperative-postoperative differences in the frequency of positional changes during sleep and the distribution of sleep positions between the nonresponse group (n = 25) and the response group (n = 28). Surgical response was defined as a greater than 50% decrease in the postoperative apnea-hypopnea index.

RESULTS

The positional change index in the response group was significantly reduced (from 4.2 +/- 3.8 to 2.6 +/- 1.6; p = 0.038), whereas the positional change index in the nonresponse group did not significantly change (from 3.4 +/- 2.0 to 3.4 +/- 2.1; p = 0.861). The proportion of sleep time spent in the supine position did not significantly change in the nonresponse group (from 62.4% +/- 18.1% to 60.5% +/- 21.3%; p = 0.904) or the response group (from 55.5% +/- 23.9% to 60.1% +/- 23.1%; p = 0.412).

CONCLUSIONS

The frequency of positional changes during sleep was significantly decreased with the improvement of respiratory disturbances and arousals in the response group after upper airway surgery.

Optimal continuous positive airway pressure level in korean patients with obstructive sleep apnea syndrome

OBJECTIVES

The aim of this study was to investigate optimal continuous positive airway pressure (CPAP) level, to examine the factors affecting optimal CPAP level, and to develop a predictive equation for optimal CPAP level in Korean patients with obstructive sleep apnea syndrome (OSAS).

METHODS

A total of 202 patients with OSAS who underwent successful manual titration for CPAP treatment were included in this study. Correlations between the optimal CPAP level and baseline data including anthropometric and polysomnographic variables were analyzed. A predictive equation for optimal CPAP level was developed based on anthropometric and polysomonographic data.

RESULTS

The mean optimal CPAP level in 202 patients with OSAS was 7.8±2.3 cm H(2)O. The mean optimal CPAP level in the mild, moderate, and severe OSAS groups was 6.0±1.3, 7.4±1.9, and 9.1±2.1 cm H(2)O, respectively. The apneahypopnea index (AHI) (r=0.595, P<0.001), arousal index (r=0.542, P<0.001), minimal SaO(2) (r=-0.502, P<0.001), body mass index (BMI) (r=0.494, P<0.001), neck circumference (r=0.265, P<0.001), and age (r=-0.164, P=0.019) were significantly correlated with optimal CPAP level. The best predictive equation according to stepwise multiple linear regression analysis was: Optimal CPAP level (cm H(2)O)=0.681+(0.205×BMI)+(0.040×AHI). Forty-two percent of the variance in the optimal CPAP level was explained by this equation (R(2)=0.42, P<0.001).

CONCLUSION

A predictive equation for optimal CPAP level in Korean patients with OSAS was developed using AHI and BMI, which can be easily measured during the diagnostic process.

Growth hormone/insulin-like growth factor-I axis in obstructive sleep apnea syndrome: an update

Obstructive sleep apnea syndrome (OSAS) is a serious, prevalent condition that has significant mortality and morbidity when untreated. It is strongly associated with obesity and is characterized by changes in the serum levels or secretory patterns of several hormones. In particular, obese patients with OSAS show a peculiar reduction of both spontaneous and stimulated GH secretion coupled with reduced IGF-I concentrations and impaired peripheral sensitivity to GH. These endocrine abnormalities are more marked than those observed in non-apneic obese subjects, and are likely to be due to the effects of hypoxia and sleep fragmentation on hormone secretory pattern. The GH/IGF-I axis activity disruption can be responsible, at least in part, for metabolic alterations, which are common in OSAS and increase the risk of cardiovascular events as well as mortality. Effective assessment and management of OSAS may correct endocrine changes, improve quality of life, and prevent associated morbidity or death.

Neuroendocrine alterations in obese patients with sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is a serious, prevalent condition that has significant morbidity and mortality when untreated. It is strongly associated with obesity and is characterized by changes in the serum levels or secretory patterns of several hormones. Obese patients with OSAS show a reduction of both spontaneous and stimulated growth hormone (GH) secretion coupled to reduced insulin-like growth factor-I (IGF-I) concentrations and impaired peripheral sensitivity to GH. Hypoxemia and chronic sleep fragmentation could affect the sleep-entrained prolactin (PRL) rhythm. A disrupted Hypothalamus-Pituitary-Adrenal (HPA) axis activity has been described in OSAS. Some derangement in Thyroid-Stimulating Hormone (TSH) secretion has been demonstrated by some authors, whereas a normal thyroid activity has been described by others. Changes of gonadal axis are common in patients with OSAS, who frequently show a hypogonadotropic hypogonadism. Altogether, hormonal abnormalities may be considered as adaptive changes which indicate how a local upper airway dysfunction induces systemic consequences. The understanding of the complex interactions between hormones and OSAS may allow a multi-disciplinary approach to obese patients with this disturbance and lead to an effective management that improves quality of life and prevents associated morbidity or death.