How does distraction osteogenesis maxillary expansion (DOME) reduce severity of obstructive sleep apnea?

Posterior Palatal Expansion via Subnasal Endoscopy (2PENN) for Maxillary Deficiency: A Pilot Study

OBJECTIVE

Surgically assisted rapid palatal expansion (SARPE) addresses transverse maxillary deficiency, a known contributor to nasal obstruction. The purpose of this study was to assess the feasibility, preliminary outcomes, and safety of posterior palatal expansion via subnasal endoscopy (2PENN), a modified SARPE procedure, aimed at achieving anterior and posterior maxillary expansion.

METHODS

This prospective case series included consecutive adult patients with findings of transverse maxillary deficiency that underwent the 2PENN procedure from 4/2021 to 4/2022. Patients completed pre- and post-operative clinical evaluations, Nasal Obstruction and Septoplasty Effectiveness (NOSE) questionnaires, and computed tomography (CT), with measures including expansion at the level of the posterior nasal spine (PNS), first maxillary inter-molar distance (IMD), and anterior nasal spine (ANS).

RESULTS

The cohort (N = 20) was middle-aged (39 ± 11 years), predominantly male (80%), and overweight (BMI 28 ± 4 kg/m2 ). The majority (85%) of patients had sleep breathing issues, of which 10 (59%) had polysomnography-confirmed obstructive sleep apnea (OSA). Full anterior-posterior separation of the mid-palatal suture line was evident on all post-operative CT scans, with mean expansion at the PNS of 3.6 ± 1.3 mm, IMD of 6.1 ± 1.6 mm and ANS of 7.0 ± 1.6 mm (p < 0.001). Following surgery, mean NOSE scores improved from 57 ± 23 to 14 ± 13 (p < 0.001). One patient required maxillary antrostomy for post-operative sinusitis.

CONCLUSION

2PENN is an effective and safe technique for achieving both anterior and posterior maxillary expansion in patients with transverse maxillary deficiency. Further study is warranted to better understand the effect of 2PENN in patients with OSA, particularly as it relates to improving pharyngeal patency.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1970-1977, 2024.

Obstructive sleep apnea for the rhinologist

PURPOSE

Obstructive sleep apnea (OSA) is a ubiquitous disease defined by repetitive partial or complete cessation of airflow during sleep caused by upper airway collapse. Otolaryngologists play a crucial role in the management of OSA, which is rapidly evolving with the advent of new surgical techniques and medical devices. Here we review the medical and surgical treatment options for OSA with a focus on unique considerations for patients with OSA who undergo nasal, sinus, and skull base surgery.

RECENT FINDINGS

Treatment of OSA includes both nonsurgical and surgical options. Positive airway pressure (PAP) therapy remains the first-line medical treatment for OSA, but alternatives such as oral appliance and positional therapy are viable alternatives. Surgical treatments include pharyngeal and tongue base surgery, hypoglossal nerve stimulation therapy, and skeletal surgery. Nasal surgery has been shown to improve sleep quality and continuous positive airway pressure (CPAP) tolerance and usage. Sinus and skull base patients with comorbid OSA have special perioperative considerations for the rhinologist to consider such as the need for overnight observation and timing of CPAP therapy resumption.

SUMMARY

OSA patients present with special considerations for the rhinologist. Patients with moderate to severe OSA may benefit from overnight observation after ambulatory surgery, especially those with an elevated BMI, cardiopulmonary comorbidities, and those who are not using CPAP regularly at home. Though CPAP may be safely resumed in the perioperative setting of nasal, sinus, and skull base surgery, the exact timing depends on patient, surgeon, and systemic factors such as severity of OSA, CPAP pressures required, extent of surgery, and the postoperative monitoring setting. Lastly, nasal and sinus surgery can improve sleep quality and CPAP tolerance and compliance in patients with OSA.

Maxillary expansion in nongrowing patients. Conventional, surgical, or miniscrew-assisted, an update

Maxillary transverse deficiency can occur in various clinical dentoskeletal deformities and include unilateral or bilateral posterior crossbite, narrow, tapering, or high palatal arch. The development of temporary anchorage devices led to a new generation of tooth-bone-borne expansion appliance using two or four screws to apply the mechanical forces to the bone and reduce the stress to the anchored teeth. The aim of these new devices is to reduce the adverse dentoalveolar effect and achieve more skeletal expansion than conventional tooth-borne rapid palatal expansion. This article reviews the age limitation and complication and soft tissue change of nonsurgical maxillary expansion. We discuss the approach of surgical maxillary expansion with maxillary skeletal expander device. The clinical case will show the benefit of nonsurgical and surgical tooth-bone-borne rapid palatal expansion.

A 3-Dimensional Measurements of Bone and Airway Variables After Le Fort I Distraction Osteogenesis in Patients With Cleft Lip and/or Palate-Induced Midface Hypoplasia: A Retrospective Study

The authors retrospectively analyzed the effects of Le Fort I advancement with distraction osteogenesis on skeletal and airway variables in patients with midfacial hypoplasia induced by cleft lip and/or palate using 3-dimensional computed tomography reconstructions. The authors enrolled 23 subjects with moderate-to-severe midface hypoplasia induced by cleft lip and palate who were treated with Le Fort I distraction osteogenesis (mean age, 19.22±3.48 y; male/female ratio, 20/3); computed tomography images (1 before distraction and another at completion of distraction) were acquired. A 3-dimensional craniometric findings and airway volumes for the nasal cavity, nasopharynx, velopharynx, and upper and lower oropharynx were compared before and after distraction. The relationships between craniofacial morphology and changes in airway volume were also assessed ( P <0.05 was considered significant). Significant increases were observed in airway volumes for the nasal cavity (13.85%), nasopharynx (50.82%), velopharynx (29.57%), and upper oropharynx (36.92%) ( P =0.007, P <0.001, P =0.023, and P <0.001, respectively), whereas no significant changes were observed for the lower oropharynx ( P =0.117). Maxillary horizontal advancement was positively correlated with the airway volumes of the nasopharynx and upper oropharynx after distraction osteogenesis ( rs =+0.451, P =0.031; rs =+0.548, P =0.007); however, no significant correlations were observed for the nasal cavity and velopharynx. The authors' finding indicate that despite rotation of the mandible along with the maxilla, this change does not impact airway volume at the mandibular level. Le Fort I distraction osteogenesis can be feasible for patients with cleft lip and palate-induced midface hypoplasia, with satisfactory appearance and occlusion. Long-term detailed follow-up of the patients postdistraction osteogenesis is warranted.

Methodological parameters for upper airway assessment by cone-beam computed tomography in adults with obstructive sleep apnea: a systematic review of the literature and meta-analysis

BACKGROUND

A reliable method for analyzing the upper airway (UA) remains a challenge. This study aimed to report the methods for UA assessment using cone-beam computed tomography (CBCT) in adults with obstructive sleep apnea (OSA).

METHODS

We performed a systematic review (PROSPERO #CRD42021237490 and PRISMA checklist) that applied a search strategy to seven databases and grey literature.

RESULTS

In 29 studies with moderate-to-high risk of bias, investigators mostly reported the body position during CBCT (upright or supine) and hard tissue references, diverging in UA delimitation and terminologies. The meta-analysis showed two subgroups (upright and supine), and no statistical differences were identified (p = 0.18) considering the UA area. The volume in the OSA group was smaller than that in the control group (p < 0.003 and Cohen's d =  - 0.81) in the upright position. Patients with OSA showed smaller anteroposterior dimensions than the control group and were not affected by the position during image acquisition (p = 0.02; Cohen's d =  - 0.52). The lateral measurements were also lower in the OSA group (supine) (p = 0.002; Cohen's d =  - 0.6).

CONCLUSIONS

Patients with OSA showed smaller UA measurements in the upright (volume) and supine (lateral dimension) positions. The anteroposterior dimension was also reduced in patients with OSA compared to the control group, regardless of the position during CBCT acquisition.

Evaluation of computational fluid dynamics models for predicting pediatric upper airway airflow characteristics

Computational fluid dynamics (CFD) has the potential for use as a clinical tool to predict the aerodynamics and respiratory function in the upper airway (UA) of children; however, careful selection of validated computational models is necessary. This study constructed a 3D model of the pediatric UA based on cone beam computed tomography (CBCT) imaging. The pediatric UA was 3D printed for pressure and velocity experiments, which were used as reference standards to validate the CFD simulation models. Static wall pressure and velocity distribution inside of the UA under inhale airflow rates from 0 to 266.67 mL/s were studied by CFD simulations based on the large eddy simulation (LES) model and four Reynolds-averaged Navier-Stokes (RANS) models. Our results showed that the LES performed best for pressure prediction; however, it was much more time-consuming than the four RANS models. Among the RANS models, the Low Reynolds number (LRN) SST k-ω model had the best overall performance at a series of airflow rates. Central flow velocity determined by particle image velocimetry was 3.617 m/s, while velocities predicted by the LES, LRN SST k-ω, and k-ω models were 3.681, 3.532, and 3.439 m/s, respectively. All models predicted jet flow in the oropharynx. These results suggest that the above CFD models have acceptable accuracy for predicting pediatric UA aerodynamics and that the LRN SST k-ω model has the most potential for clinical application in pediatric respiratory studies.

Does surgically assisted maxillary expansion improve obstructive sleep apnoea in adults? A systematic review and meta-analysis

Introduction The aim of this systematic review and meta-analysis was to evaluate the effects of maxillary expansion on adults with obstructive sleep apnoea (OSA).Methods Electronic searches up to July 2021 in eight electronic databases were conducted. Study selection, data extraction, risk of bias evaluation using ROBINS-I, quality of evidence assessment using GRADE and meta-analyses were performed.Results The electronic searches yielded 1,007 studies. Following the application of the eligibility criteria, 15 articles were fully read and five studies were included. The studies evaluated the effects of surgically assisted rapid maxillary expansion in adults with OSA. The meta-analysis demonstrated an improvement in Apnoea-Hypopnea Index (AHI) (MD = -9.91, CI = -14.57 to -5.25), Oxygen Desaturation Index (ODI) (MD = -7.95, CI = -12.23 to -3.67), and Epworth Sleepiness Scale (ESS) (MD = -4.40, CI = -6.39 to -2.40). ROBINS-I indicated serious, no information and critical risk of bias for the included studies. The quality of the evidence was very low.Conclusion The findings herein suggest that maxillary expansion could improve OSA in adults in the short term.

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

A Minimally Invasive Nasal Endoscopic Approach to Distraction Osteogenesis Maxillary Expansion to Restore Nasal Breathing for Adults with Narrow Maxilla

Background: Patients with narrow high-arch palate present with limited response to standard septal, turbinate, and valve procedures for nasal obstruction. Objective: To measure the effectiveness of minimally invasive nasal endoscopic (MINE) Lefort I osteotomy among subjects with narrow high-arched palate in managing nasal obstruction. Methods: Prospective cohort study was performed where subjects with narrow high-arched palate underwent MINE distraction osteogenesis maxillary expansion (DOME) from August 2019 to January 2021. Nasal obstruction symptom evaluation (NOSE) score, mean time to opioid cessation, and mean duration of cranial nerve V2 hypoesthesia were evaluated. Results: Among 12 subjects, the. mean NOSE score decreased from 58.89 to 15.83 (p = 0.004). There were no complaints of lip mobility or deformity. Conclusion: MINI-DOME can reduce nasal obstruction in a certain phenotype of patients and further improve patient-centric outcomes by limiting the approach to the Lefort I osteotomy to an endoscopic nasal approach.

Feasibility of Distraction Osteogenesis Maxillary Expansion (DOME) in patients with persistent nasal obstruction after septoplasty

BACKGROUND

Distraction osteogenesis maxillary expansion (DOME) is an emerging surgical concept for obstructive sleep apnea patients presenting with nasal obstruction, with a high-arched and narrow hard palate. We demonstrate the feasibility of DOME in the treatment of patients with persistent nasal obstruction after primary septoplasty.

METHODS

A total of 32 consecutive patients with persistent nasal obstruction after septoplasty who underwent DOME were enrolled in this study. The efficacy of DOME in treating persistent nasal obstruction in septoplasty failure patients was evaluated by using the validated Nasal Obstruction Symptom Evaluation (NOSE) scale. Pre- and postoperative computed tomography (CT) scans were performed to measure the change of nasal floor width after surgery.

RESULTS

The NOSE score significantly improved from 13.62±4.74 to 5.15±3.50 (p<0.001) after DOME. The postoperative CT scan showed a significant increase of the nasal floor width from 22.4±4.21 to 28.06±4.52 (p<0.01). No patient experienced major complications, such as wound infection, oronasal fistula, sinusitis, loss of incisor teeth, and malunion.

CONCLUSIONS

This study shows that DOME appears to improve persistent nasal obstruction after septoplasty in patients with narrow and high-arched hard palate. This article is protected by copyright. All rights reserved.

A Comprehensive Strategy for Improving Nasal Outcomes After Large Maxillomandibular Advancement for Obstructive Sleep Apnea

Background: Rate of corrective nasal surgery after maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA) has been reported to be 18.7% for functional and aesthetic indications. Objective: Describe a comprehensive strategy to optimize nasal outcomes with MMA for OSA. Methods: A retrospective review of patients undergoing MMA for OSA in a tertiary referral center was performed, with a comprehensive perioperative intervention to optimize nasal outcomes from January 2014 to February 2018. Outcomes included the Apnea-Hypopnea Index (AHI), oxygen saturation (SpO₂) nadir, corrective nasal surgery needed after MMA, and Nasal Obstruction Symptom Evaluation (NOSE) scores. Results: AHI after MMA showed significant reduction (-34.65, p < 0.001), SpO₂ nadir increased (+6.08, p < 0.001), and NOSE scores decreased (-5.96, p < 0.001). Corrective nasal surgery needed after MMA was reported in 6.5% (8 of 122) subjects at a mean of 8.5 months, ranging from 1 to 24.7 months. Six subjects underwent either septoplasty and/or valve stenosis repair, and two subjects underwent functional and aesthetic rhinoplasty. Conclusion: A perioperative strategy was applied since 2014 that showed effectiveness in reducing post-MMA corrective nasal surgery to 6.5%.

Correlation between the transverse dimension of the maxilla, upper airway obstructive site, and OSA severity

STUDY OBJECTIVES

Acquiring a better comprehension of obstructive sleep apnea physiopathology can contribute to improving patient selection for surgical treatments. We hypothesize that maxillary transverse deficiency restricts the space available for the tongue, leading to upper airway obstruction during sleep. Our primary hypothesis was that maxillary transverse deficiency increases the prevalence of tongue collapse during drug-induced sleep endoscopy (DISE). The secondary hypothesis was that maxillary transverse deficiency will also increase the prevalence of circumferential collapse at the velopharynx. The exploratory hypothesis was that maxillary transverse deficiency is associated with increased obstructive sleep apnea severity. The objectives of this study were to correlate maxillary morphometric measurements with (1) the anatomic level of obstruction during DISE and (2) the apnea-hypopnea index on polysomnography.

METHODS

We made a cross-sectional analysis of patients with obstructive sleep apnea undergoing DISE in search of positive airway pressure alternative treatment. Maxillary measurements were collected from a computed tomography scan (interpremolar distance, intermolar distance [IMD] and sella-nasion A point angle), findings from DISE, and sleep study variables from polysomnography. Correlation between computed tomography, DISE, and polysomnography data was assessed using Pearson's correlation, and receiver operating characteristic curves were determined for each facial measurement.

RESULTS

Sixty-nine patients were included in the study. The group with velopharyngeal circumferential collapse had mean IMD = 26.30 mm (25.5-31.45), and the group with anteroposterior collapse had mean IMD = 29.20 mm (26.8-33.10; P = .040). The group with complete tongue-base obstruction had mean interpremolar distance = 26.40 mm (25.1-28) and IMD = 26.30 mm (25.6-28.4), and the group without obstruction had mean interpremolar distance = 28.7 mm (27.2-30; P = .003) and IMD = 34.06 mm (32.1-37; P < .001). The receiver operating characteristic curve determined an IMD cutoff of 29.8 mm for predicting tongue-base obstruction.

CONCLUSIONS

The maxillary transverse deficiency, identified by reduction in interpremolar distance and IMD, predicted the occurrence of complete tongue-base obstruction, complete concentric collapse at the velopharynx, and multilevel obstruction during DISE. We did not find an association between the maxillary measurements and obstructive sleep apnea severity. These associations hold some promise in ultimately supplanting insights previously available only through DISE.

Effect of tube length on the buckling pressure of collapsible tubes

BACKGROUND

The higher incidence of obstructive sleep apnea (OSA) in men than in women has been attributed to the upper airway being longer in men. The Starling resistor is the paradigm biomechanical model of upper airway collapse in OSA where a collapsible tube (representing the pharynx) is located between two rigid tubes (representing the nasal cavity and trachea). While the Starling resistor has been extensively studied due to its relevance to many physiological phenomena, the effect of tube length on tube collapsibility has not been quantified yet.

METHODS

Finite element analysis of a 3-dimensional collapsible tube subjected to a transmural pressure was performed in ANSYS Workbench. The numerical methods were validated with in vitro experiments in a silicone tube whose modulus of elasticity (361 ± 28 kPa) and dimensions (length = 100 mm, diameter = 22.2 mm, and wall thickness = 1.59 mm) were selected so that tube compliance was similar to pharyngeal compliance in humans during sleep. The buckling pressure (transmural pressure at which the tube collapses) was quantified in tubes of three different diameters (10 mm, 16 mm, and 22.2 mm) and ten length-to-diameter ratios (L/D = 4 to 13), while keeping the wall-thickness-to-radius ratio constant at 0.143.

RESULTS

The absolute value of the buckling pressure decreased from 4.7 to 3.3 cmH₂O (461-324 Pa) when L/D increased from 4 to 13. The buckling pressure was nearly independent from tube length for L/D >10.

CONCLUSIONS

Our finding that longer tubes are more collapsible than shorter tubes is consistent with the higher incidence of obstructive sleep apnea in males than females.

Nasal ventilation and rapid maxillary expansion (RME): a randomized trial

OBJECTIVE

To assess three rapid maxillary expansion (RME) appliances in nasal ventilation.

TRIAL DESIGN

Three-arm parallel randomized clinical trial.

METHODS

Sixty-six growing subjects (10-16 years old) needing RME as part of their orthodontic treatment were randomly allocated (1:1:1 ratio) to three groups of 22 patients receiving Hyrax (H), Hybrid-Hyrax (HH), or Keles keyless expander (K). The primary outcome of nasal ventilation (pressure and velocity) and secondary outcomes (skeletal, dental, soft tissue, and nasal obstruction changes) were blindly assessed on the initial (T0) and final (T1, 6 months at appliance removal) cone-beam computed tomography (CBCT) data by applying computational fluid dynamics (CFD) method. Differences across groups were assessed with crude and adjusted for baseline values and confounders (gender, age, skeletal maturation, expansion amount, mucosal/adenoid hypertrophy, nasal septum deviation) regression models with alpha = 5%.

RESULTS

Fifty-four patients were analysed (19H, 21HH, 14K). RME reduced both nasal pressure (H: -45.8%, HH: -75.5%, K: -63.2%) and velocity (H: -30%, HH: -58.5%, K: -35%) accompanied with nasal obstruction resolution (H: 26%, HH: 62%, K: 50%). Regressions accounting for baseline severity indicated HH expander performing better in terms of post-expansion maximum velocity (P = 0.03) and nasal obstruction resolution (P = 0.04), which was robust to confounders. Mucosal/adenoid hypertrophy and nasal septum deviation changes were variable, minimal, and similar across groups. The HH resulted in significantly greater increase in the nasal cross-sectional area (62.3%), anterior (14.6%), and posterior (10.5%) nasal widths. Nasal obstruction resolution was more probable among younger (P = 0.04), skeletally immature (P = 0.03), and male patients (P = 0.02) without pre-treatment mucosal hypertrophy (P = 0.04), while HH was associated with marginal greater probability for obstruction resolution.

CONCLUSIONS

RME resulted in improvement of nasal skeletal parameters and simulated ventilation with the former being in favour of the HH and the latter not showing significant differences among the three appliances.

LIMITATION

Attrition in the K group due to blocked activation rods possibly leading to limited sample to identify any existing group differences.

HARMS

Replacement of blocked Keles expanders for finalizing treatment.

PROTOCOL

The protocol was not published before the trial commencement.

REGISTRATION

Australian and New Zealand Clinical Trial Registry; ACTRN12617001136392.

Computational Fluid Dynamics Analysis of Nasal Airway Changes after Treatment with C-Expander

The use of the C-expander is an effective treatment modality for maxillary skeletal deficiencies which can cause ailments and significantly reduce life expectancy in late adolescents and young adults. However, the morphological and dynamic effects on the nasal airway have not been reported. The main goal of this study was to evaluate the nasal airway changes after the implementation of a C-expander. A sample of nine patients (8 females, 1 male, age range from 15 to 29 years) was included. The morphology parameters and nasal airway ventilation parameters of pretreatment and posttreatment were measured. All study data were normally distributed. A paired t-test was used to evaluate the changes before and after treatment. After expansion, the mean and standard deviation values of intercanine maxillary width (CMW) and intermolar maxillary width (MMW) increased from 35.75 ± 2.48 mm and 54.20 ± 3.17 mm to 37.87 ± 2.26 mm (P < 0.05) and 56.65 ± 3.10 mm (P < 0.05), respectively. The nasal cavity volume increased from 20320.00 ± 3468.25 mm³ to 23134.70 ± 3918.84 mm³ (P < 0.05). The nasal pressure drop decreased from 36.34 ± 3.99 Pa to 30.70 ± 3.17 Pa (P < 0.05), while the value of the maximum velocity decreased from 6.50 ± 0.31 m/s to 5.85 ± 0.37 m/s (P < 0.05). Nasal resistance dropped remarkably from 0.16 ± 0.14 Pa/ml/s to 0.08 ± 0.06 Pa/ml/s (P < 0.05). The use of C-expander can effectively broaden the area and volume of the nasal airway, having a positive effect in the reduction of nasal resistance and improvement of nasal airway ventilation. For patients suffering from maxillary width deficiency and respiratory disorders, a C-expander may be an alternative method to treat the disease.

Surgical Algorithm for Obstructive Sleep Apnea: An Update

Sleep surgery is part of a continuum of care for obstructive sleep apnea (OSA) that involves medical, pharmacologic, and behavioral therapy. Upper airway surgery for OSA can significantly improve stability by way of modulating the critical negative closing pressure. This is the same mechanism of action as positive airway pressure or oral appliance therapy. The updated surgical algorithm in this review adds precision in three areas: patient selection, identification of previously unaddressed anatomic phenotypes with associated treatment modality, and improved techniques of previously established procedures. While the original Riley and Powell phase 1 and 2 approach to sleep surgery has focused on individual surgical success rate, this algorithm strives for an overall treatment success with multi-modal and patient-centric treatments.