Changes in the calibre of the upper airway and the surrounding structures after maxillomandibular advancement for obstructive sleep apnoea

Modified maxillomandibular advancement surgery for the treatment of obstructive sleep apnoea: a scoping review

Modified maxillomandibular advancement (MMMA) has been proposed as an alternative to the classic maxillomandibular advancement (MMA) in East and Southeast Asian populations in which bimaxillary protrusion is a prevalent trait. The key difference between MMMA and MMA is the inclusion of anterior segmental osteotomies to reduce the protrusion of the perioral region. The aim of this scoping review was to identify the variations in MMMA and treatment outcomes. A search was conducted in the PubMed, Embase, and Cochrane electronic databases for articles published up to January 2023. Ten articles were included in this review. Three variations of MMMA have been reported in the literature. Treatment outcomes have mostly been favourable for all of these variations. Mandibular advancement of >10 mm and a greater than 50% reduction in the apnoea-hypopnoea index (AHI) have been well reported. Improvements in other outcome measures, such as enlargement of the airway dimension on computed tomography and the Epworth Sleepiness Scale score, have also been shown. Despite additional surgical procedures, complications have been uncommon and mostly minor in nature. It is necessary to be cognizant of MMMA and its variations when providing sleep surgery for East and Southeast Asian patients, tailoring this to the patient's profile and needs.

An Overview of Systematic Reviews on the Surgical Management of Obstructive Sleep Apnoea

Background

Obstructive Sleep Apnoea (OSA) is a common sleep disorder marked by partial or total obstruction of the upper airway while a person is asleep leading to breathing difficulty, reduced oxygenation and frequent awakenings. This condition affects the general health significantly compromising quality of life. The objective of this overview  is to thoroughly assess the systematic reviews on current surgical therapies for the management of OSA in terms of patient outcomes.

Methods

A thorough literature search was performed from inception till 31st December 2022 using PubMed, and Cochrane databases. Studies evaluating the effectiveness and safety of different surgical techniques for the management of OSA were considered. The quality of articles was assessed using AMSTAR (A MeaSurement Tool to Assess systematic Reviews) and Glenny et al. checklist.

Results

Out of eighteen studies, only seven studies met the inclusion and exclusion criteria. Results showed that the majority of studies were in the pediatric age group except one systematic  review which assessed the adult age group.

Conclusion

None of the published articles had compared all surgical procedures based on the standard evaluating procedure nor followed all reporting guidelines in the primary studies. For better implementation, further multi center studies are warranted with unique reporting criteria and guidelines about pre- as well as post-operative phases. Future research should concentrate on contrasting strategies, combination therapies, and evaluating long-term effects.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12663-023-02051-x.

Three-dimensional evaluation of the association between tongue position and upper airway morphology in adults: A cross-sectional study

Objective

This study aimed to evaluate the association between low tongue position (LTP) and the volume and dimensions of the nasopharyngeal, retropalatal, retroglossal, and hypopharyngeal segments of the upper airway.

Methods

A total of 194 subjects, including 91 males and 103 females were divided into a resting tongue position (RTP) group and a LTP group according to their tongue position. Subjects in the LTP group were divided into four subgroups (Q1, Q2, Q3, and Q4) according to the intraoral space volume. The 3D slicer software was used to measure the volume and minimum and average cross-sectional areas of each group. Airway differences between the RTP and LTP groups were analyzed to explore the association between tongue position and the upper airway.

Results

No significant differences were found in the airway dimensions between the RTP and LTP groups. For both retropalatal and retroglossal segments, the volume and average cross-sectional area were significantly greater in the patients with extremely low tongue position. Regression analysis showed that the retroglossal airway dimensions were positively correlated with the intraoral space volume and negatively correlated with A point-nasion-B point and palatal plane to mandibular plane. Males generally had larger retroglossal and hypopharyngeal airways than females.

Conclusions

Tongue position did not significantly influence upper airway volume or dimensions, except in the extremely LTP subgroup.

Influence of Surgeon Experience on Surgical Outcome of Maxillomandibular Advancement for Obstructive Sleep Apnea

The primary aim of this study was to assess the association between clinical efficacy outcomes (i.e., polysomnography (PSG) results) of maxillomandibular advancement (MMA) and surgeons' experience. The second aim was to assess the association between the occurrence of postoperative complications of MMA and surgeons' experiences. Patients treated with MMA for moderate to severe obstructive sleep apnea (OSA) were enrolled in this retrospective study. The patient population was divided into two groups based on two different surgeons performing MMA. The associations between surgeons' experience on the one hand and PSG results and postoperative complications on the other hand were investigated. A total of 75 patients were included. There was no significant difference in baseline characteristics between the two groups. The reductions in apnea-hypopnea index and oxygen desaturation index were both significantly greater in group-B than group-A (p = 0.015 and 0.002, respectively). The overall success rate after MMA was 64.0%. There was a negative correlation between surgeon experience and surgical success (odds ratio: 0.963 [0.93, 1.00], p = 0.031). No significant association was found between surgeon experience and surgical cure. Additionally, there was no significant association between surgeon experience and the occurrence of postoperative complications. Within the limitations of this study, it is concluded that surgeon experience may have little to no influence on the clinical efficacy and safety of MMA surgery in OSA patients.

Maxillomandibular Advancement and Upper Airway Stimulation for Treatment of Obstructive Sleep Apnea: A Systematic Review

This systematic review aimed to comparatively evaluate the efficacy and safety of maxillomandibular advancement (MMA) and upper airway stimulation (UAS) in obstructive sleep apnea (OSA) treatment. A MEDLINE and Embase database search of articles on MMA and/or UAS for OSA was conducted. Twenty-one MMA studies and nine UAS studies were included. All the MMA studies demonstrated a reduction in apnea hypopnea index (AHI) postoperatively, and success rates ranged from 41.1% to 100%. Ten MMA studies reported pre- and postoperative Epworth sleepiness scale (ESS), and all but one study demonstrated a reduction in ESS. In the UAS studies, all but one demonstrated a reduction in AHI, and success rates ranged from 26.7% to 77.8%. In the eight UAS studies reporting pre- and postoperative ESS, an ESS reduction was demonstrated. No studies reported any deaths related to MMA or UAS. The most common postoperative complications after MMA and UAS were facial paresthesia in the mandibular area and discomfort due to electrical stimulation, respectively. This systematic review suggests that both MMA and UAS are effective and generally safe therapies for OSA. However, due to the limitations of the included studies, there is no evidence yet to directly compare these two procedures in OSA treatment.

Comparison of airway changes after maxillomandibular advancement with or without genial tubercle advancement in obstructive sleep apnea using cone-beam computed tomography

INTRODUCTION

This study compared the airway changes of patients with obstructive sleep apnea (OSA) after maxillomandibular advancement (MMA) with or without genial tubercle advancement (GTA) using cone-beam computed tomography.

METHODS

The authors retrospectively studied 26 patients with moderate to severe OSA who underwent MMA with or without GTA. Airway changes were determined from preoperative and postoperative 3-dimensional reconstructed cone-beam computed tomography images. The Wilcoxon signed rank test, Mann-Whitney U tests, and Spearman correlation coefficients were used in data analysis.

RESULTS

Airway was changed in all dimensions significantly after MMA with or without GTA. There was no significant difference in horizontal surgical changes between MMA and MMA with the GTA group. The mean increase in total airway volume was 66.8% for MMA alone and 74.7% for MMA with GTA (P = 0.39). Patients who underwent MMA had a larger percentage change of segmented upper airway volume than patients with MMA and GTA (106.6% vs 85.3%; P = 0.65). The group with MMA and GTA had a greater percentage change of segmented lower airway volume than the MMA alone group (80.1% vs 56.3%; P = 0.42).

CONCLUSIONS

Differences in airway changes between MMA alone and MMA with GTA were not statistically significant. Performing the GTA concomitantly with MMA may not cause greater improvement in the pharyngeal airway in patients with OSA compared with MMA alone.

Current and Novel Treatment Options for OSA

Obstructive sleep apnoea is a challenging medical problem due to its prevalence, its impact on quality of life and performance in school and professionally, the implications for risk of accidents, and comorbidities and mortality. Current research has carved out a broad spectrum of clinical phenotypes and defined major pathophysiological components. These findings point to the concept of personalised therapy, oriented on both the distinct clinical presentation and the most relevant pathophysiology in the individual patient. This leads to questions of whether sufficient therapeutic options other than positive airway pressure (PAP) alone are available, for which patients they may be useful, if there are specific indications for single or combined treatment, and whether there is solid scientific evidence for recommendations. This review describes our knowledge on PAP and non-PAP therapies to address upper airway collapsibility, muscle responsiveness, arousability and respiratory drive. The spectrum is broad and heterogeneous, including technical and pharmaceutical options already in clinical use or at an advanced experimental stage. Although there is an obvious need for more research on single or combined therapies, the available data demonstrate the variety of effective options, which should replace the unidirectional focus on PAP therapy.

The analysis of individual pathophysiological composition opens new directions towards personalised treatment of OSA, focusing not only on pharyngeal dilation, but also on technical or pharmaceutical interventions on muscle function or breathing regulationhttps://bit.ly/3sayhkd

Skeletal and upper airway stability following modified maxillomandibular advancement for treatment of obstructive sleep apnea in skeletal class I or II deformity

OBJECTIVES

Maxillomandibular advancement (MMA) is an effective short-term treatment for obstructive sleep apnea (OSA). This study aimed to evaluate the long-term stability of the facial skeleton, upper airway, and its surrounding structures, as well as improvement in OSA following MMA.

MATERIALS AND METHODS

Thirty-one adults with moderate-to-severe OSA underwent surgery-first modified MMA as primary surgery. Polysomnography and cone-beam computed tomography were obtained pre-surgery, early post-surgery, and at follow-up (i.e., ≥ 2 years post-surgery). Image analysis software assessed the facial skeleton, upper airway, and its surrounding structures.

RESULTS

Early post-surgery, apnea-hypopnea index (AHI) had decreased significantly (p < 0.001) and the minimum oxygen saturation (MSAT) increased (p = 0.001), indicating significant improvement in OSA. At follow-up, the AHI and MSAT remained stable. However, the anterior maxilla, soft palate, and tongue moved backward while the hyoid moved downward. There was also a significant decrease in the minimal cross-sectional area of the oropharynx. The reduction in AHI was significantly related to the anterior movement of the anterior maxilla and tongue, inferior movement of the posterior maxilla, and superior movement of the soft palate tip.

CONCLUSIONS

The improvement of OSA after modified MMA remained stable for at least 2 years following treatment, despite the relapse of the facial skeleton, upper airway, and its surrounding structures. The reduction of AHI was not related to changes in the caliber of the upper airway but to the movement of the maxilla, soft palate, and tongue. Clinical relevance Modified MMA is clinically effective for long-term treatment of patients with moderate-to-severe OSA.

Intra-individual variation of upper airway measurements based on computed tomography

The aims of this study were (1) to quantify the intra-individual variation in the upper airway measurements on supine computed tomography (CT) scans at two different time points; and (2) to identify the most stable parameters of the upper airway measurements over time. Ten subjects with paired CT datasets (3-6 months interval) were studied, using computer software to segment and measure the upper airway. The minimum cross-sectional area of the total airway and all its segments (velopharynx, oropharynx, tongue base, and epiglottis) generally had the largest variation, while the length of the total airway had the lowest variation. Sphericity was the only parameter that was stable over time (relative difference <15%), both in the total airway and each subregion. There was considerable intra-individual variation in CT measurements of the upper airway, with the same patient instruction protocol for image acquisitions. The length of the total airway, and the sphericity of the total upper airway and each segment were stable over time. Hence, such intra-individual variation should be taken into account when interpreting and comparing upper airway evaluation parameters on CT in order to quantify treatment results or disease progress.

Referral of adults with obstructive sleep apnea for surgical consultation: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment

INTRODUCTION

This systematic review provides supporting evidence for the accompanying clinical practice guideline on the referral of adults with obstructive sleep apnea (OSA) for surgical consultation.

METHODS

The American Academy of Sleep Medicine commissioned a task force of experts in sleep medicine. A systematic review was conducted to identify studies that compared the use of upper airway sleep apnea surgery or bariatric surgery to no treatment as well as studies that reported on patient-important and physiologic outcomes pre- and postoperatively. Statistical analyses were performed to determine the clinical significance of using surgery to treat obstructive sleep apnea in adults. Finally, the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence for making recommendations.

RESULTS

The literature search resulted in 274 studies that provided data suitable for statistical analyses. The analyses demonstrated that surgery as a rescue therapy results in a clinically significant reduction in excessive sleepiness, snoring, blood pressure (BP), apnea-hypopnea index (AHI), respiratory disturbance index (RDI), oxygen desaturation index (ODI), increase in lowest oxygen saturation (LSAT), sleep quality, and improvement in quality of life in adults with OSA who are intolerant or unaccepting of positive airway pressure (PAP) therapy. The analyses demonstrated that surgery as an adjunctive therapy results in a clinically significant reduction in optimal PAP pressure and improvement in PAP adherence in adults with OSA who are intolerant or unaccepting of PAP due to side effects associated with high pressure requirements. The analyses also demonstrated that surgery as an initial treatment results in a clinically significant reduction in AHI/RDI, sleepiness, snoring, BP, and ODI, and increase in LSAT in adults with OSA and major anatomical obstruction. Analysis of bariatric surgery data showed a clinically significant reduction in BP, AHI/RDI, sleepiness, snoring, optimal PAP level, BMI, ODI, and an increase in LSAT in adults with OSA and obesity. Analyses of very limited evidence suggest that upper airway surgery does not result in a clinically significant increase in risk of serious persistent adverse events and suggested that bariatric surgery may result in a clinically significant risk of iron malabsorption that may be managed with iron supplements. The task force provided a detailed summary of the evidence along with the quality of evidence, the balance of benefits and harms, patient values and preferences, and resource use considerations.

Skeletal Stability and Airway Changes After Maxillary Advancement Using a Rigid External Distraction System in Non-Growing Cleft Patients

ABSTRACT

Distraction osteogenesis (DO) is a highly effective technique for correction of severe maxillary hypoplasia, especially in patients with orofacial clefts and craniofacial syndromes. The purpose of this retrospective, longitudinal study was to assess long-term airway alterations after maxillary advancement using a rigid external distraction system (RED) in non growing cleft patients. Fifteen cleft patients (8 males and 7 females) aged from 14 to 25 years were included in this study. All of them were treated with a rigid external distraction system for maxillary advancement after a high Le Fort I osteotomy. To analyse airway changes lateral cephalograms were obteined before distraction (T0), immediately after distraction (T1) and 1 to 3 years and 3 months after distraction (T2). All the measurements were describled by means of median, minimum and maximum. In order to evaluate differences between each time interval, a Wilcoxon test associated to a Delta Cliff test was used to evaluate the effect size (level of significance adopted was 5%). A significant maxillary advancement and increased upper airway antero-posterior dimensions were observed after the distraction osteogeness process, as demonstrated by the difference between T1 and T0. No significant relapse at T2 was found. Lower airway and the airway at tip of uvula region did not display significant alterations. A significant maxillary advancement and increased antero-posterior upper airway dimension was measured immediately after maxillary distraction with rigid external distraction in non growing cleft patients. The findings were stable three years after distraction.

Upper airways after mandibular advancement orthognathic surgery: A 4-year follow-up

INTRODUCTION

The purpose of this study was to assess the stability of changes in the upper airways 4 years after orthognathic surgery in patients with skeletal Class II malocclusion.

METHODS

A retrospective clinical study was conducted including 33 cone-beam computed tomography images from 11 patients (average age of 35.91 years) followed up longitudinally for 4 years. The airways were measured with the help of the Dolphin Imaging software (Dolphin Imaging and Management Systems, Chatsworth, Calif) at 3 points: T1 (preoperative), T2 (6 months after surgery), and T3 (4 years after surgery). The parameters assessed were surface area (SA), minimum axial area, and volume (VOL) of the pharyngeal airway space. The times were compared using analysis of variance and Tukey's test. Pearson's analysis was performed to assess the correlation with surgical changes and age (P <0.05).

RESULTS

Four years after operating on the airway spaces, the means of SA and VOL were significantly higher than those observed before the surgery (P <0.05). The means at 6 months were intermediate, with no significant difference before the surgery and 4 years after it (P >0.05). There was no significant correlation of the changes in SA, VOL, and minimum axial area with the amount of mandibular advancement, counterclockwise rotation of the occlusal plane, and age of the patient (P >0.05).

CONCLUSIONS

Four years after mandibular advancement surgery in patients with skeletal Class II malocclusion, the increases in the airways remained stable.

Maxillomandibular advancement versus multilevel surgery for treatment of obstructive sleep apnea: A systematic review and meta-analysis

Multilevel surgery (MLS) and maxillomandibular advancement surgery (MMA) are two established options in surgical management of obstructive sleep apnea (OSA), which target different levels of airway obstruction. The objective of this review was to comparatively evaluate the clinical efficacy and safety of MMA and MLS in the treatment of OSA. MEDLINE and Embase databases were searched for studies on MMA and/or MLS in OSA patients. Twenty MMA studies and 39 MLS studies were identified. OSA patients who underwent MMA showed significant improvements in AHI, LSAT, ODI, and ESS by -46.2/h, 13.5%, -30.3/h, and -8.5, respectively. The pooled rates of surgical success and cure for MMA were 85.0% and 46.3%, respectively. Patients who underwent MLS showed significant improvements in AHI, LSAT, ODI, and ESS by -24.7/h, 8.7%, -19.1/h, and -5.8, respectively. The pooled surgical success and cure rates for MLS were 65.1% and 28.1%, respectively. The rates of major complication of MMA and MLS were 3.2% and 1.1%, respectively, and the rate of minor complication of MMA was higher than that of MLS. We conclude that both MMA and MLS are effective treatment options for OSA. Compared to MLS, MMA may be more effective in improving OSA. However, the complication rate of MMA is higher.

Impact of counterclockwise rotation of the occlusal plane on the mandibular advancement, pharynx morphology, and polysomnography results in maxillomandibular advancement surgery for the treatment of obstructive sleep apnea patients

PURPOSE

Evaluate the impact of counterclockwise rotation of the occlusal plane (CCWROP) on pharynx morphology and polysomnography in maxillomandibular advancement (MMA) surgery to treat obstructive sleep apnea (OSA) patients.

METHODS

Prospective clinical trial of patients with OSA treated by MMA. Computed tomography and polysomnography were performed pre- and postoperatively and the parameters were compared. The surgery classified the patients into two groups: with (R) and without (NR) CCWROP.

RESULTS

The study sample comprised 38 individuals: R (n = 19) and NR (n = 19). An anterior mandible advancement of 0.71 mm was identified for each degree of CCWROP (p < 0.001). As for polysomnography, the apnea-hypopnea index was reduced by 80% and 62% in R and NR, showing final values of 6.8 and 13.0, respectively. The apnea index changed equally in both groups. Reduction of 68 and 26% in the hypopnea index was observed for R and NR, respectively, with no statistically significant difference. Total volume increased by 45% in R and 30% in NR. Retropalatal and retrolingual volumes increased by 49% and 4% in R and 43% and 15% in NR, respectively. The minimum axial area increased by 92% in the retropalatal region and 97% in the retrolingual region in R, whereas these increases were of 76% and 31% in NR, respectively.

CONCLUSION

Anterior mandibular advancement of 0.71 mm for each degree of CCWROP is of great importance for surgical planning. As a result of this resource, individuals in R presented better results than those in NR in all parameters assessed, especially regarding the retrolingual region.

The correlation of maxillomandibular advancement and airway volume change in obstructive sleep apnea using cone beam computed tomography

The purpose of this retrospective study was to evaluate the correlation of maxillomandibular advancement (MMA) and airway volume changes in patients with obstructive sleep apnea (OSA), and to determine the surgical skeletal movements necessary to achieve an increase in total airway volume (TAV) of ≥70%. Thirty patients with OSA treated by MMA were evaluated. Pre- and postoperative cone beam computed tomography images were used to determine the horizontal distance and angular changes in surgical parameters and linear, area, and volumetric airway parameters. Postoperatively, the horizontal distance of surgical parameters (A-point, UI, B-point, pogonion, and menton) and craniofacial angulation (SNA and SNB) increased significantly, similar to total surface area, TAV, and minimum cross-sectional area of the airway (p<0.0001). The total airway length decreased significantly (p<0.0001). The mean increase in TAV was 67.2%. There were positive correlations between linear surgical changes and the percentage change in TAV. All surgical parameters were predictive of a change in TAV ≥70%. The optimal surgical change was 6mm for A-point, 7.9mm for UI, 7.6mm for B-point, 11.2mm for pogonion, and 10mm for menton. In conclusion, maxillary advancement of less than 10mm was adequate in this study to obtain an increase in the TAV of at least 70%.

Velopharyngeal Space Assessment in Patients Undergoing Le Fort 1 Maxillary Advancement

Background:

The effects of maxillary advancement on velopharyngeal anatomy have primarily been studied using lateral cephalometric radiographs. However, with recent advances in orthognathic surgery, there is an increased need for more detailed and precise imaging such as computerized tomographic (CT) scan reconstructions, to help in surgical planning and to measure outcomes. The purpose of this study was to compare the pre- and post-operative velopharyngeal anatomic configuration modifications as measured on CT scans.

Methods:

This is a retrospective cohort study of 44 patients with and without cleft palate who were treated with maxillary advancement. The pre- and post-operative CT scans were compared with respect to pre-established landmarks. Linear distances, cross-sectional areas, and volumes were measured using 3-dimensional CT scan reconstructions.

Results:

For the linear distances measured, a statistically significant difference was found when comparing the pre- and post-operative measures of the narrowest part of the nasopharynx and the narrowest part of the retropalatal airway space (P = 0.001 and 0.026, respectively). Retropalatal cross-sectional areas, nasopharyngeal cross-sectional areas, and the volumetric assessment of the nasopharyngeal space showed no statistically significant differences when comparing pre- and post-operative scans (P < 0.05). Mean changes in the measures did not differ over time (pre- and post-operative) depending on whether there was a prior history of cleft palate repair.

Conclusions:

Although structural modifications of the pharyngeal space are inherent to maxillary advancement, its surface area and volume do not significantly change. The use of 3-dimensional reconstruction using CT scans should be the first choice for evaluation of the upper airway.

Why most patients do not exhibit obstructive sleep apnea after mandibular setback surgery?

Maxillomandibular advancement (MMA) is effective for the treatment of obstructive sleep apnea (OSA). In previous studies, the airway was increased in the anteroposterior and transverse dimensions after MMA. However, the effect of the opposite of mandibular movement (mandibular setback) on the airway is still controversial. Mandibular setback surgery has been suggested to be one of the risk factors in the development of sleep apnea. Previous studies have found that mandibular setback surgery could reduce the total airway volume and posterior airway space significantly in both the one-jaw and two-jaw surgery groups. However, a direct cause-and-effect relationship between the mandibular setback and development of sleep apnea has not been clearly established. Moreover, there are only a few reported cases of postoperative OSA development after mandibular setback surgery.

These findings may be attributed to a fundamental difference in demographic variables such as age, sex, and body mass index (BMI) between patients with mandibular prognathism and patients with OSA. Another possibility is that the site of obstruction or pattern of obstruction may be different between the awake and sleep status in patients with OSA and mandibular prognathism. In a case-controlled study, information including the BMI and other presurgical conditions potentially related to OSA should be considered when evaluating the airway. In conclusion, the preoperative evaluation and management of co-morbid conditions would be essential for the prevention of OSA after mandibular setback surgery despite its low incidence.

Impact of surgical maxillomandibular advancement upon pharyngeal airway volume and the apnoea-hypopnoea index in the treatment of obstructive sleep apnoea: systematic review and meta-analysis

Background

A systematic review was carried out on the effect of surgical maxillomandibular advancement (MMA) on pharyngeal airway (PA) dimensions and the apnoea-hypopnoea index (AHI) in the treatment of obstructive sleep apnoea (OSA), with the aim of determining whether increased PA in the context of MMA is the main factor conditioning the subsequent decrease in AHI.

Methods

A search was made of the PubMed, Embase, Google Scholar and Cochrane databases. A total of 496 studies were identified. The inclusion criteria were a diagnosis of moderate to severe OSA, MMA success evaluated by polysomnography, reporting of the magnitude of MMA achieved, PA increase and a minimum follow-up of 6 months.

Results

Following application of the eligibility criteria, eight articles were included. Metaregression analysis showed MMA to significantly increase both pharyngeal airway volume (PAV) (mean 7.35 cm³ (range 5.35-9.34)) and pharyngeal airway space (mean 4.75 mm (range 3.15-6.35)) and ensure a final AHI score below the threshold of 20 (mean 12.9 events/hour).

Conclusions

Although subgroup analysis showed MMA to be effective in treating OSA, more randomised trials are needed to individualise the required magnitude and direction of surgical movements in each patient, and to standardise the measurements of linear and nonlinear PAV parameters.

Computational analysis of airflow dynamics for predicting collapsible sites in the upper airways: a preliminary study

The present study aimed to detail the relationship between the flow and structure characteristics of the upper airways and airway collapsibility in obstructive sleep apnea. Using a computational approach, we performed simulations of the flow and structure of the upper airways in two patients having different facial morphologies: retruding and protruding jaws, respectively. First, transient flow simulation was performed using a prescribed volume flow rate to observe flow characteristics within upper airways with an unsteady effect. In the retruding jaw, the maximum magnitude of velocity and pressure drop with velocity shear and vortical motion was observed at the oropharyngeal level. In contrast, in the protruding jaw, the overall magnitude of velocity and pressure was relatively small. To identify the cause of the pressure drop in the retruding jaw, pressure gradient components induced by flow were examined. Of note, vortical motion was highly associated with pressure drop. Structure simulation was performed to observe the deformation and collapsibility of soft tissue around the upper airways using the surface pressure obtained from the flow simulation. At peak flow rate, the soft tissue of the retruding jaw was highly expanded, and a collapse was observed at the oropharyngeal and epiglottis levels.

NEW & NOTEWORTHY Aerodynamic characteristics have been reported to correlate with airway occlusion. However, a detailed mechanism of the phenomenon within the upper airways and its impact on airway collapsibility remain poorly understood. This study provides in silico results for aerodynamic characteristics, such as vortical structure, pressure drop, and exact location of the obstruction using a computational approach. Large deformation of soft tissue was observed in the retruding jaw, suggesting that it is responsible for obstructive sleep apnea.

Long-term Results for Maxillomandibular Advancement to Treat Obstructive Sleep Apnea: A Meta-analysis

Objective

To examine outcomes in the intermediate term (1 to <4 years), long term (4 to <8 years), and very long term (≥8 years) for maxillomandibular advancement (MMA) as treatment for obstructive sleep apnea (OSA).

Data Sources

The Cochrane Library, Google Scholar, Embase, Cumulative Index to Nursing and Allied Health, and PubMed/MEDLINE.

Review Methods

Three authors systematically reviewed the international literature through July 26, 2018.

Results

A total of 445 studies were screened, and 6 met criteria (120 patients). Thirty-one patients showed a reduction in apnea-hypopnea index (AHI) from a mean 48.3 events/h (95% CI, 42.1-54.5) pre-MMA to 8.4 (95% CI 5.6, 11.2) in the intermediate term. Fifty-four patients showed a reduction in AHI from a mean 65.8 events/h (95% CI, 58.8-72.8) pre-MMA to 7.7 (95% CI 5.9, 9.5) in the long term. Thirty-five showed a reduction in AHI from a mean 53.2 events/h (95% CI 45, 61.4) pre-MMA to 23.1 (95% CI 16.3, 29.9) in the very long term. Improvement in sleepiness was maintained at all follow-up periods. Lowest oxygen saturation improvement was maintained in the long term.

Conclusion

The current international literature shows that patients with OSA who were treated with MMA maintained improvements in AHI, sleepiness, and lowest oxygen saturation in the long term; however, the mean AHI increased to moderate OSA in the very long term. Definitive generalizations cannot be made, and additional research providing individual patient data for the intermediate term, long term, and very long term is needed.

Controversies in Obstructive Sleep Apnea Surgery

Obstructive sleep apnea (OSA) is a common chronic disease characterized by repetitive pharyngeal collapse during sleep. OSA is associated with cardiovascular disease and increased mortality, among other issues. Continuous positive airway pressure (CPAP) is considered first line therapy for OSA, but is not always tolerated. Both non-surgical and surgical alternative management strategies are available for the CPAP intolerant patient. This article explores controversies surrounding airway evaluation, definition of successful treatment, and surgical management of the CPAP intolerant patient with moderate to severe OSA. Controversies specific to maxillomandibular advancement (MMA) are also discussed.

Impact of Bimaxillary Advancement Surgery on the Upper Airway and on Obstructive Sleep Apnea Syndrome: a Meta-Analysis

Upper airway changes following bimaxillary advancement surgery to treat obstructive sleep apnea syndrome remain controversial. The main objective of this systematic review and meta-analysis was to investigate the effects of bimaxillary advancement surgery on the upper airway (UA) of obstructive sleep apnea syndrome patients through examining changes three-dimensionally in vertical and supine position and through changes in oximetric variables (AHI, RDI, O2 Sat) and in the quality of life measured by the Epworth sleepiness scale (ESS). A thorough search of the PubMed, Scopus, Embase and Cochrane databases and a grey literature search (Opengrey) were conducted. No limit was placed on publication year or language. The inclusion criteria were: adult obstructive sleep apnea patients who had undergone bimaxillary advancement surgery, three-dimensional CBCT or CT and oximetric measurements and at least six weeks follow-up. Sample sizes of under 10 patients were excluded. Finally, 26 articles were included in the qualitative review and 23 in the meta-analysis. Bimaxillary advancement surgery has been shown to be beneficial in terms of increased upper airway size, improved oximetric indicators and the quality of life measured on the Epworth sleepiness scale.

Airway Changes after Cleft Orthognathic Surgery Evaluated by Three-Dimensional Computed Tomography and Overnight Polysomnographic Study

Cleft lip and palate is the most common congenital craniofacial anomaly. Up to 60% of these patients will benefit from cleft orthognathic surgery, which consists primarily of maxillary advancement and mandibular setback to address midface retrusion and relative mandibular protrusion, respectively. It is believed that maxillary advancement can enlarge the airway whilst mandibular setback can reduce the airway, but this has not previously been quantified for cleft patients undergoing orthognathic surgery. This unique longitudinal prospective study of 18 patients was conducted between April 2013 and July 2016. No significant changes occurred by six months postoperatively in body mass index, apnoea-hypopnoea index or lowest oxygen saturation (LSAT). There was a mean increase of 0.73 cm3 in velopharyngeal volume, a mean decrease of 0.79 cm3 in oropharyngeal volume, an improvement in snoring index, and no statistically significant change in hypopharyngeal volume. In conclusion, cleft orthognathic surgery that produced anterior advancement of the maxilla, setback of the mandible and clockwise rotation of the maxillo-mandibular complex resulted in increased velopharyngeal, decreased oropharyngeal and unchanged hypopharyngeal airways, and improved snoring, but did not significantly alter objective sleep-related breathing function.

Subtypes of Maxillomandibular Advancement Surgery for Patients With Obstructive Sleep Apnea

Maxillomandibular advancement (MMA) surgery, which is the most effective treatment modality for patients with moderate-to-severe obstructive sleep apnea with apparent skeletal discrepancies, has been modified in conjunction with segmental osteotomies, counterclockwise rotation of maxillomandibular complex, and other adjunctive procedures. However, any single type of MMA could not treat or cure all the patients with obstructive sleep apnea showing different dentofacial and pharyngeal patterns. We aimed to suggest critical decision factors for the selective application of MMA subtypes, categorized as straight MMA with genioplasty, rotational MMA, segmental MMA, and segmental-rotational MMA, in the surgical treatment objective process: anteroposterior position of maxilla, upper lip projection, overjet, lower incisor inclination as sagittal factors, and upper incisor exposure and occlusal plane angle as vertical factors. This case series deserves a clinical basis on the way of case-by-case application of the optimal MMA subtype based on the successful treatment outcomes with short-term stability.

Orthognathic Surgery: A Review of Articles Published in 2014-2015

OBJECTIVES

We did a retrospective study and reviewed some of the orthognathic surgery related papers that were published between January 2014 and December 2015 in a leading International Maxillofacial Surgery Journal. It was conducted to ascertain the trends of articles being published.

METHOD

A total of around 57 articles were reviewed, of which most of the full length articles were on post operative outcomes and obstructive sleep apnoea.

RESULTS

Bulk of the studies were retrospective, and less interest was shown onto experimental researches.

CONCLUSION

A thorough review and analysis thus gives an impression that there is a high requirement of well designed clinical studies.

Volumetric and cephalometric evaluation of the upper airway of class III patients submitted to maxillary advancement

Abstract Introduction Anteroposterior maxillary deficiency can be associated with a decrease of upper airway volume. Maxillary advancement can improve the upper airway space. Aim To correlate cephalometric (2D) and volumetric (3D) measurements of the upper airway in class III patients treated by maxillary advancement. Material and method This retrospective transversal study was performed in ten adult patients submitted to maxillary advancement for correction of class III deformity secondary to maxillary anteroposterior deficiency. The Cone beam tomography files included in the medical records were used: (T1) pre-operative and (T2) 6 to 8 months postoperative. The DICOM files were imported and reconstructed for volumetric and cephalometric evaluation of the upper airway, as divided into nasopharynx, oropharynx and hypopharynx (Arnett & Gunson FAB Surgery). Result Age ranged from 26 to 55 years with a mean of 36.3±9.2 years. There were no statistically significant differences for cephalometric and volumetric parameters of the three pharyngeal regions between T1 and T2 periods. This was due to the small amount of maxillary advancement necessary to correct the maxillary deformity in the studied patients (4.7±1.89mm). The correlation between area and volume was not statistically significant only for preoperative measurements of the nasopharynx (r=0.30, p=0.40). It was significant for the other regions and evaluation periods (p<0.05). Conclusion Small maxillary advancements do not result in significant increases in airway dimensions.

Cervical computed tomography in patients with obstructive sleep apnea: influence of head elevation on the assessment of upper airway volume

OBJECTIVE

Obstructive sleep apnea syndrome (OSAS) has a high prevalence and carries significant cardiovascular risks. It is important to study new therapeutic approaches to this disease. Positional therapy might be beneficial in reducing the apnea-hypopnea index (AHI). Imaging methods have been employed in order to facilitate the evaluation of the airways of OSAS patients and can be used in order to determine the effectiveness of certain treatments. This study was aimed at determining the influence that upper airway volume, as measured by cervical CT, has in patients diagnosed with OSAS.

METHODS

This was a quantitative, observational, cross-sectional study. We evaluated 10 patients who had been diagnosed with OSAS by polysomnography and on the basis of the clinical evaluation. All of the patients underwent conventional cervical CT in the supine position. Scans were obtained with the head of the patient in two positions (neutral and at a 44° upward inclination), and the upper airway volume was compared between the two.

RESULTS

The mean age, BMI, and neck circumference were 48.9 ± 14.4 years, 30.5 ± 3.5 kg/m2, and 40.3 ± 3.4 cm, respectively. The mean AHI was 13.7 ± 10.6 events/h (range, 6.0-41.6 events/h). The OSAS was classified as mild, moderate, and severe in 70%, 20%, and 10% of the patients, respectively. The mean upper airway volume was 7.9 cm3 greater when the head was at a 44° upward inclination than when it was in the neutral position, and that difference (17.5 ± 11.0%) was statistically significant (p = 0.002).

CONCLUSIONS

Elevating the head appears to result in a significant increase in the caliber of the upper airways in OSAS patients.

Stability of Modified Maxillomandibular Advancement Surgery in a Patient With Preadolescent Refractory Obstructive Sleep Apnea

Maxillomandibular advancement (MMA) surgery can be considered a primary single-stage treatment for improving the quality of life in patients with preadolescent refractory obstructive sleep apnea (OSA). The aim of the present report was to evaluate the treatment efficacy and stability of modified MMA surgery in a growing patient with morbidly severe symptoms and medical complications. Using the follow-up results from the questionnaire, polysomnography, 2-dimensional cephalometry, and 3-dimensional cone-beam computed tomography measurements, the success of modified MMA surgery was assessed in terms of the postoperative improvements of functions and esthetics and postretentive stability of the improvements throughout the growth period. The present report provides some clinical recommendations when considering skeletal surgery in preadolescent patients with OSA: 1) the decision criteria of MMA surgery as definite treatment; 2) the proper surgical design for both maximum enlargement of the airway and esthetic improvement; and 3) the postoperative facial growth for long-term stability of airway function and skeletal improvement. With a systematic multidisciplinary approach, early surgical intervention can be used to treat OSA in children successfully and permanently.

Lateral Pharyngeal Wall Tension After Maxillomandibular Advancement for Obstructive Sleep Apnea Is a Marker for Surgical Success: Observations From Drug-Induced Sleep Endoscopy

PURPOSE

The efficacy of maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA) with anatomic airway changes has previously been studied using static imaging and endoscopy in awake subjects. The aim of the present study was to use drug-induced sleep endoscopy (DISE) to evaluate the dynamic upper airway changes in sleeping subjects before and after MMA and their association with the surgical outcome.

PATIENTS AND METHODS

This was a retrospective cohort study of subjects with OSA who had undergone MMA at the Stanford University Sleep Surgery Division from July 2013 to July 2014. The subjects were included if perioperative polysomnography and DISE had been performed. The predictor variable was the perioperative DISE velum-oropharynx-tongue-epiglottis score. The outcome variables were the apnea-hypopnea index (AHI), oxygen-desaturation index (ODI), and Epworth Sleepiness Scale (ESS). A subgroup analysis was performed for the subjects who had undergone primary and secondary MMA. The statistical analyses included Cronbach's α coefficient, the McNemar test, and the independent Student t test. The P value was set at <.01.

RESULTS

A total of 16 subjects (15 males, 1 female) were included in the present study, with an average age of 47 ± 10.9 years and body mass index of 29.4 ± 5.1 kg/m(2). Significant post-MMA decreases were found in the AHI (from 59.8 ± 25.6 to 9.3 ± 7.1 events/hr) and ODI (from 45 ± 29.7 to 5.7 ± 4.1 events/hr; P < .001). Greater improvement in the AHI occurred in the primary MMA group (P = .022). The post-MMA change in airway collapse was most significant at the lateral pharyngeal wall (P = .001). The subjects with the most improvement in lateral pharyngeal wall collapsibility demonstrated the largest changes in the AHI (from 60.0 ± 25.6 events/hr to 7.5 ± 3.4 events/hr) and ODI (from 46.7 ± 29.8 to 5.3 ± 2 events/hr; P = .002).

CONCLUSIONS

Using DISE, we observed that after MMA, the greatest reduction in upper airway collapsibility is seen at the lateral pharyngeal wall of the oropharynx, followed by the velum, and then the tongue base. The stability of the lateral pharyngeal wall is a marker of surgical success after MMA using the AHI, ODI, and ESS.

Maxillomandibular Advancement and Tracheostomy for Morbidly Obese Obstructive Sleep Apnea

Objective

The objective of this study is to systematically review polysomnography data and sleepiness in morbidly obese (body mass index [BMI] ≥40 kg/m2) patients with obstructive sleep apnea (OSA) treated with either a maxillomandibular advancement (MMA) or a tracheostomy and to evaluate the outcomes.

Data Sources

MEDLINE, Scopus, Web of Science, and the Cochrane Library.

Review Methods

A search was performed from inception through April 8, 2014, in each database.

Results

Six maxillomandibular advancement studies (34 patients, age 42.42 ± 9.13 years, mean BMI 44.88 ± 4.28 kg/m2) and 6 tracheostomy studies (14 patients, age 52.21 ± 10.40 years, mean BMI 47.93 ± 7.55 kg/m2) reported individual patient data. The pre- and post-MMA means ± SDs for apnea-hypopnea indices were 86.18 ± 33.25/h and 9.16 ± 7.89/h ( P < .00001), and lowest oxygen saturations were 66.58% ± 16.41% and 87.03% ± 5.90% ( P < .00001), respectively. Sleepiness following MMA decreased in all 5 patients for whom it was reported. The pre- and posttracheostomy mean ± SD values for apnea indices were 64.43 ± 41.35/h and 1.73 ± 2.68/h ( P = .0086), oxygen desaturation indices were 69.20 ± 26.10/h and 41.38 ± 36.28/h ( P = .22), and lowest oxygen saturations were 55.17% ± 16.46% and 79.83% ± 4.36% ( P = .011), respectively. Two studies reported outcomes for Epworth Sleepiness Scale for 5 patients, with mean ± SD values of 18.80 ± 4.02 before tracheostomy and 2.80 ± 2.77 after tracheostomy ( P = .0034).

Conclusion

Data for MMA and tracheostomy as treatment for morbidly obese, adult OSA patients are significantly limited. We caution surgeons about drawing definitive conclusions from these limited studies; higher level studies are needed.

Linear and volumetric airway changes after maxillomandibular advancement for obstructive sleep apnea

PURPOSE

Maxillomandibular advancement (MMA) surgery is a well-established treatment of obstructive sleep apnea (OSA). Although many studies have assessed the efficacy of MMA in treating OSA, very few studies have quantified the magnitude of its changes to airway morphology. Therefore, the present study investigated the linear and volumetric morphologic changes that occur in the pharyngeal airway after treatment of OSA using MMA.

MATERIALS AND METHODS

A retrospective cohort study of patients with OSA treated from May 2010 to February 2014 was performed. Each patient underwent preoperative clinical and fiberoptic nasopharyngoscopic examinations. Pre- and postoperative polysomnograms, lateral cephalograms, and cone-beam computed tomography scans were acquired. The radiographic images were used to determine the linear and volumetric airway measurements. The time and magnitude of skeletal movement were used as the independent variables. The dependent variables included assessment of success or cure, apnea hypopnea index (AHI), cephalometric changes, Epworth score, rapid eye movement sleep, body mass index, and various airway morphologic parameters.

RESULTS

A total of 15 patients (13 men and 2 women) participated in the present study. The surgical success and cure rate was 73.33% and 40.00%, respectively. Statistically significant improvements were found in the airway total volume, minimal cross-sectional area, anteroposterior and lateral dimensions, airway index, airway length, posterior airway space morphology, AHI, and Epworth sleepiness score.

CONCLUSIONS

MMA is a highly successful surgical treatment of OSA that improves airway morphology and sleep quality. MMA results in a shorter and broader airway and associated improvements in the AHI.

Modified maxillomandibular advancement for obstructive sleep apnoea: towards a better outcome for Asians

Excluding tracheostomy, maxillomandibular advancement (MMA) is the most effective surgical treatment for obstructive sleep apnoea (OSA). However, the anticipated facial changes may prevent acceptance of this procedure by patients with bimaxillary protrusion, a common feature of Asian faces. We therefore developed a modified MMA technique for such cases, consisting of anterior segmental osteotomies together with standard Le Fort I and bilateral sagittal split osteotomies. A prospective study of 20 consecutive Taiwanese adults with moderate-to-severe OSA who underwent modified MMA and postsurgical orthodontics was undertaken to evaluate the efficacy with regard to OSA and the postoperative facial appearance and dental occlusion. After modified MMA, the mean apnoea-hypopnoea index decreased from 41.6±19.2 n/h to 5.3±4.0 n/h (P<0.001). All patients had a successful outcome. No patient was dissatisfied with their postoperative facial appearance. The mean Peer Assessment Rating score decreased from 21.9±14.3 to 1.7±1.6 (P=0.001). The data suggest that the modified MMA is effective in treating patients with moderate-to-severe OSA without negatively affecting facial appearance or dental occlusion. To achieve a better outcome, surgical-orthodontic integration is warranted. The surgery-first approach can achieve early improvement.

Innovative treatments for adults with obstructive sleep apnea

Obstructive sleep apnea (OSA) affects one in five adult males and is associated with significant comorbidity, cognitive impairment, excessive daytime sleepiness, and reduced quality of life. For over 25 years, the primary treatment has been continuous positive airway pressure, which introduces a column of air that serves as a pneumatic splint for the upper airway, preventing the airway collapse that is the physiologic definition of this syndrome. However, issues with patient tolerance and unacceptable levels of treatment adherence motivated the exploration of other potential treatments. With greater understanding of the physiologic mechanisms associated with OSA, novel interventions have emerged in the last 5 years. The purpose of this article is to describe new treatments for OSA and associated complex sleep apnea. New approaches to complex sleep apnea have included adaptive servoventilation. There is increased literature on the contribution of behavioral interventions to improve adherence with continuous positive airway pressure that have proven quite effective. New non-surgical treatments include oral pressure devices, improved mandibular advancement devices, nasal expiratory positive airway pressure, and newer approaches to positional therapy. Recent innovations in surgical interventions have included laser-assisted uvulopalatoplasty, radiofrequency ablation, palatal implants, and electrical stimulation of the upper airway muscles. No drugs have been approved to treat OSA, but potential drug therapies have centered on increasing ventilatory drive, altering the arousal threshold, modifying loop gain (a dimensionless value quantifying the stability of the ventilatory control system), or preventing airway collapse by affecting the surface tension. An emerging approach is the application of cannabinoids to increase upper airway tone.