Changes In Airway Volume Research Articles

Effects of a fixed functional appliance on upper airway volume: A 3-dimensional cone-beam computed tomography study

Although functional appliances (FAs) are primarily used to treat Class II malocclusions, their effects on the upper airway have generally been reported in studies involving 2-dimensional analysis of cephalometric radiographs. This study aimed to use 3-dimensional cone-beam computed tomographyto (1) determine the effects on upper airway volume and minimum cross-sectional area (MCA)when an FA is used for orthodontic treatment and (2) identify pretreatment markers for airway changes. Pre- and posttreatment cone-beam computed tomography scans were selected from 73 children whose orthodontic treatment involved using a fixed FA (37 girls and 36 boys; mean age 12.0years); a control group was constituted and included the scans of 73 children who were matched for chronological age, skeletal age, sex, and mandibular inclination and who received orthodontic treatment for minor malocclusions without an FA. Changes in upper airway volume and MCA were evaluated by a standardized, previously validated method analyzed with mixed-effects linear regression. Upper airway volume and MCA increased over time for both the FA and the matched control groups (P<0.05). The FA caused an additional significant increase in upper airway volume and MCA (P<0.0001) when compared with the control group. An increased ANB angle, a reduced mandibular inclination, and a reduced skeletal age pretreatment had a positive effect on upper airway volume and MCA (P<0.05). A fixed FA was associated with a significant increase in upper airway volume and MCA in children when compared with controls. Pretreatment ANB angle, skeletal age, and mandibular inclination may be predictors for positive changes in the upper airway. The results may prove valuable in treating children with Class II malocclusions with compromised upper airways.

The upper airway volume effects produced by Hyrax, Hybrid-Hyrax, and Keles keyless expanders: a single-centre randomized controlled trial.

To assess upper airway volume changes after rapid maxillary expansion (RME) with three different expanders. Three-arm parallel randomized clinical trial. Sixty-six patients, 10-16 years old, in permanent dentition, with maxillary transverse deficiency were recruited and assigned with block randomization (1:1:1 ratio) and allocation concealment to three groups of 22 patients each (Hyrax, Hybrid-Hyrax, and Keles keyless expander). The primary outcome (overall upper airway volume change) and secondary outcomes (volume changes in the nasal cavity, nasopharynx, oropharynx, and hypopharynx) were blindly assessed on the initial (T0) and final (T1, 6 months at appliance removal) cone beam computed tomography. Differences across groups were assessed with crude or adjusted for confounders (gender, age, growth stage, skeletal pattern, baseline airway volume, and amount of expansion) linear regression models. Fifty-one patients were analysed (19, 19, and 13 in the Hyrax, Hybrid-Hyrax, and Keles groups). Maxillary expansion resulted in considerable increases in total airway volume in the Hybrid-Hyrax group (+5902.1 mm3) and less in the Hyrax group (+2537.9 mm3) or the Keles group (+3001.4 mm3). However, treatment-induced changes for the primary and all secondary outcomes were of small magnitude and no significant difference was seen among the three expanderes in the total airway volume in either crude or adjusted analyses (P > 0.05 in all instances). Finally, among pre-peak patients (CVM 1-3), the Hybrid-Hyrax expander was associated with significantly greater increases in total airway volume compared to the Hyrax expander (P = 0.02). RME resulted in relatively small increases in total upper airway volume and its separate compartments, with mostly no statistically significant differences across the Hyrax, Hybrid-Hyrax, and Keles groups. Significantly greater attrition was found in the Keles group due to appliance failure. The current trial might possibly be under-powered to detect differences between groups, if such exist. Keles expanders blocked during activations and required substitution for completion of treatment. The protocol was not published before trial commencement. Australian and New Zealand Clinical Trial Registry (ACTRN12617001136392).

Changes in pharyngeal airway volume after mandibular advancement and maxillomandibular advancement: a cone beam computed tomography study

article: Changes in pharyngeal airway volume after mandibular advancement and maxillomandibular advancement: a cone beam computed tomography study - European Journal of Oral and Maxillofacial Surgery 2020 August;4(2):35-44 - Minerva Medica - Journals

Does endo-tracheal tube clamping prevent air leaks and maintain positive end-expiratory pressure during the switching of a ventilator in a patient in an intensive care unit? A bench study.

ObjectivesWhen patients with acute respiratory distress syndrome are moved out of an intensive care unit, the ventilator often requires changing. This procedure suppresses positive end expiratory pressure and promotes lung derecruitment. Clamping the endotracheal tube may prevent this from occurring. Whether or not such clamping maintains positive end-expiratory pressure has never been investigated. We designed a bench study to explore this further.How the study was doneWe used the Elysee 350 ventilator in ‘volume controlled’ mode with a positive end-expiratory pressure of 15 cmH2O, connected to an endotracheal tube with an 8 mm internal diameter inserted into a lung model with 40 ml/cmH2O compliance and 10 cmH2O/L/s resistance. We measured airway pressure and flow between the distal end of the endotracheal tube and the lung model. We tested a plastic, a metal, and an Extra Corporeal Membrane Oxygenation clamp, each with an oral/nasal, a nasal, and a reinforced endotracheal tube. We performed an end-expiratory hold then clamped the endotracheal tube and disconnected the ventilator. We measured the change in airway pressure and volume for 30 s following the disconnection of the ventilator.ResultsAirway pressure decreased thirty seconds after disconnection with all combinations of clamp and endotracheal tube. The largest fall in airway pressure (-17.486 cmH2O/s at 5 s and -18.834 cmH2O/s at 30 s) was observed with the plastic clamp combined with the reinforced endotracheal tube. The smallest decrease in airway pressure (0 cmH2O/s at 5 s and -0.163 cmH2O/s at 30 s) was observed using the Extra Corporeal Membrane Oxygenation clamp with the nasal endotracheal tube.ConclusionsOnly the Extra Corporeal Membrane Oxygenation clamp was efficient. Even with an Extra Corporeal Membrane Oxygenation clamp, it is important to limit the duration the ventilator is disconnected to a few seconds (ideally 5 s).

Effects of symmetric and asymmetric rapid maxillary expansion treatments on pharyngeal airway and sinus volume.

To evaluate pharyngeal airway and maxillary sinus volumes following symmetric rapid maxillary expansion (RME) and asymmetric rapid maxillary expansion (ARME) treatment using cone-beam computed tomography (CBCT). The study consisted of 60 patients presenting to the orthodontics clinic with an indication that they required symmetric or asymmetric rapid maxillary expansion treatment. Individuals were included if they were aged 12-15 years and had symmetric (RME group; 14 girls, 16 boys) or asymmetric (ARME group; 16 girls, 14 boys) maxillary deficiency. Maxillary sinus volume (mm3) and pharyngeal airway volume (upper, lower, and total; mm3) were evaluated using CBCT records. The parameters were compared before treatment (T1) and after 3 months in retention (T2). All measurements at T2 were increased significantly compared with T1 in the RME group (P < .05). In the ARME group, changes in the lower pharyngeal airway and the nonaffected maxillary sinus volumes (non-affected side of maxillary sinus volumes) were not significant; however, the other measurements increased significantly from T1 to T2 (P < .05). Intergroup comparisons revealed that total pharyngeal airway volume and total maxillary sinus volume changes were significantly greater in the RME group. Pharyngeal airway and maxillary sinus volumes increased with both RME and ARME treatment. Both were found to be effective for treating transverse maxillary deficiency.

Idiopathic pulmonary fibrosis: airway volume measurement identifies progressive disease on computed tomography scans.

Airways tell a tale: measuring change in airway volume using functional respiratory imaging can differentiate between stable and progressive idiopathic pulmonary fibrosis on CT scans #imagebiomarkers #ipf http://bit.ly/2M8KVLl

COMPUTATIONAL FLUID DYNAMICS MODELING OF PHARYNGEAL AIRWAY RESISTANCE BASED ON CONE-BEAM COMPUTED TOMOGRAPHY

Background: Oral appliances for treating patients with sleep related disorders such as snoring and disturbed sleep could alter the morphology of the pharyngeal airway and thus its flow dynamics as well as airway patency. Splint therapy, i.e., positioning the mandibular condyles in centric relation (CR) with maxillary anterior guided orthotics (MAGO), with regard to pharyngeal airway patency, is causing increased attention. The goal of this work is to quantitatively examine the fluid dynamic changes within the pharyngeal airway when the mandible is positioned in CR and its association with airway patency. Materials and Methods: Patient-specific computational fluid dynamics models were reconstructed from pre- and post- treatment high-resolution cone-beam computed tomography images for two patients who had undergone MAGO therapy. The minimal cross-sectional area and total volume of the pharyngeal airway were measured in the pre- and post-treatment for a total of four models. These two subjects were chosen out of 18 patients based on the airway volume changes in pre- and post-treatment. Subject 1 had a dramatic increase in the airway volume, whereas subject 2 kept a similar airway volume following the therapy. Both subjects anecdotally reported improvement in snoring, breathing and overall sleep quality. Results: We examined three parameters, i.e., the classically defined resistance of airway in terms of pressure drop, the minimal cross-sectional area, and the pharyngeal airway volume. We also proposed a new fluid dynamic parameter: the percentage area of higher vorticity, to be correlated with the clinical efficacy of the appliance for airway patency. All four parameters could be used as index factors for subject 1 to explain the measurable clinical outcomes and the subjective report regarding quality of breathing, snoring cessation, and improvement in sleep of the patient. But only the minimal cross-sectional area and percentage area of higher vorticity could explain the clinical observations and subjective outcome in subject 2 who reported similar effects after the treatment. Conclusion: Splint therapy expanded the minimal cross-sectional area in both subjects, but did not necessarily influence the pharyngeal airway volume. The airway shape changed in terms of the percentage area of higher vorticity and the minimal cross-sectional area. Further studies are needed to assess the clinical efficacy of MAGO in reducing or eliminating the sleep-related breathing difficulties and snoring.

Bronchial thermoplasty increases airway volume measured by functional respiratory imaging

BackgroundThe purpose of this study was to use CT scanning with computational fluid dynamics to evaluate the mechanisms by which Bronchial Thermoplasty (BT) improves asthmatic symptoms.MethodsThe study was conducted in a university teaching hospital, experienced in performing BT. Imaging studies were performed before, and after, BT of the left lung, and prior to treatment of the right lung, which therefore acted as a control. On each occasion, two high-resolution CT scans were performed, one at full inspiration (TLC) and the other at Functional Residual Capacity (FRC). The study protocol was offered to 10 patients, all of whom met the definition of severe asthma, despite high dose inhaled corticosteroids and dual long acting bronchodilators.ResultsSignificant increases in airway luminal volume were observed on the treated side, compared with control, at both full inspiration (by 27%) and at FRC (by 17%). The ratio of distal airway volume to lung volume significantly increased on the treated side. The change in airway volume with inspiration from FRC increased by 48% on the treated side compared to 5% in the control lung, suggesting treatment increased airway distensibility. No effect was observed on airway wall thickness, nor air trapping. There was a trend towards correlation between the improvement in airway volume at TLC and improvement in symptoms.ConclusionThis study demonstrates that BT increases the luminal airway volume on the treated side compared to the control lung. We suggest that this is an important link between the airway smooth muscle atrophy demonstrated pathologically, and the improvement in symptoms observed clinically.

Multi-modal Framework for Image-guided Trans-oral Surgery with Intraoperative Imaging and Deformation Modeling.

Treatment of throat cancers have improved due to minimally-invasive trans-oral approaches. Surgeons rely on preoperative imaging to guide their resection; however, large tissue deformations occur during trans-oral procedures due to placement of necessary retractors and laryngoscopes which hinders the surgeon's ability to accurately assess tumor extent and location of critical structures. We propose an image-guided framework utilizing intraoperative imaging and deformation modeling to improve surgeon accuracy and confidence. A CT-compatible laryngoscopy system previously developed was evaluated in this framework. Intraoperative images were acquired during laryngoscopy; force-sensing capabilities were enabled in the laryngoscope; and tracking of the scope and anatomic features was trialed. Tissue deformation and displacement were quantified and determined to be extensive, with values <; 4.6 cm in the tongue, <; 1.8 cm in bony structures, and <; 108.9 cm3 in airway volume change. Surgical navigation using intraoperative imaging and tracking was evaluated. Preliminary assessment of deformation modeling showed potential to supplement intraoperative imaging. Future work will involve streamlined integration of the components of this framework.

Effects of rapid maxillary expansion on upper airway volume: A three-dimensional cone-beam computed tomography study.

To compare changes in pharyngeal airway volume and minimal cross-sectional area (MCA) between patients undergoing rapid maxillary expansion (RME) and a matched control group and to identify markers for predicting airway changes using cone-beam computed tomography (CBCT). Pre- and posttreatment CBCT scans were selected of children who had RME (14 girls and 12 boys; mean age, 12.4 years) along with scans of a control group (matched for chronological age, skeletal age, gender, mandibular inclination) who underwent orthodontic treatment for minor malocclusions without RME. Changes in airway volume and MCA were evaluated using a standardized, previously validated method and analyzed by a mixed-effects linear regression model. Upper airway volume and MCA increased significantly over time for both the RME and matched control groups (P < .01 and P = .05, respectively). Although the RME group showed a greater increase when compared with the matched controls, this difference was not statistically significant. A reduced skeletal age before treatment was a significant marker for a positive effect on the upper airway volume and MCA changes (P < .01). Tooth-borne RME is not associated with a significant change in upper airway volume or MCA in children when compared with controls. The younger the skeletal age before treatment, the more positive the effect on the upper airway changes. The results may prove valuable, especially in RME of young children.

Retrospective CBCT analysis of airway volume changes after bone-borne vs tooth-borne rapid maxillary expansion.

To compare changes in upper airway volume after maxillary expansion with bone- and tooth-borne appliances in adolescents and to evaluate the dentoskeletal effects of each expansion modality. This retrospective study included 36 adolescents who had bilateral maxillary crossbite and received bone-borne maxillary expansion (average age: 14.7 years) or tooth-borne maxillary expansion (average age: 14.4 years). Subjects had two cone beam computed tomography images acquired, one before expansion (T1) and a second after a 3-month retention period (T2). Images were oriented, and three-dimensional airway volume and dentoskeletal expansion were measured. Analysis of variance was used to test for differences between the two expansion methods for pretreatment, posttreatment, and prepost changes. Paired t-tests were used to test for significance of prepost changes within each method. Both groups showed significant increase only in nasal cavity and nasopharynx volume (P < .05), but not oropharynx and maxillary sinus volumes. Intermolar and maxillary width increased significantly in both groups (P < .05); however, the buccal inclination of maxillary molars increased significantly only in the tooth-borne group (P < .05). There was no significant difference between tooth- and bone-borne expansion groups, except for the significantly larger increase in buccal inclination of the maxillary right first molar after tooth-borne expansion. In adolescents, both tooth- and bone-borne RME resulted in an increase in nasal cavity and nasopharynx volume, as well as expansion in maxillary intermolar and skeletal widths. However, only tooth-borne expanders caused significant buccal tipping of maxillary molars.

Bedside respiratory physiology to detect risk of lung injury in acute respiratory distress syndrome.

The most effective strategies for treating the patient with acute respiratory distress syndrome center on minimizing ventilation-induced lung injury (VILI). Yet, current standard-of-care does little to modify mechanical ventilation to patient-specific risk. This review focuses on evaluation of bedside respiratory mechanics, which when interpreted in patient-specific context, affords opportunity to individualize lung-protective ventilation in patients with acute respiratory distress syndrome. Four biophysical mechanisms of VILI are widely accepted: volutrauma, barotrauma, atelectrauma, and stress concentration. Resulting biotrauma, that is, local and systemic inflammation and endothelial activation, may be thought of as the final common pathway that propagates VILI-mediated multiorgan failure. Conventional, widely utilized techniques to assess VILI risk rely on airway pressure, flow, and volume changes, and remain essential tools for determining overdistension of aerated lung regions, particularly when interpreted cognizant of their limitations. Emerging bedside tools identify regional differences in mechanics, but further study is required to identify how they might best be incorporated into clinical practice. Quantifying patient-specific risk of VILI requires understanding each patient's pulmonary mechanics in context of biological predisposition. Tailoring support at bedside according to these factors affords the greatest opportunity to date for mitigating VILI and alleviating associated morbidity.

Impact of Middle Turbinectomy on Airflow to the Olfactory Cleft: A Computational Fluid Dynamics Study.

The impact of middle turbinate resection (MTR) on olfaction remains a point of debate in the current literature. Few studies have objectively evaluated olfactory cleft airflow following MTR; thus, the mechanism by which MTR may impact olfaction is poorly understood. It is not known whether the postsurgical changes in airway volume, flow, and resistance increase odorant transport or disrupt the patterns of normal airflow. Computational fluid dynamics can be used to study the nasal airway and predict responses to surgical intervention. To evaluate the functional impact of MTR on nasal airflow, resistance, and olfaction. Five maxillofacial computed tomography scans of patients without signs of significant sinusitis or nasal polyposis were used. Control models for each patient were compared to their corresponding model after virtual total MTR. For each model, nasal airway volume, nasal resistance, and air flow rate were determined. Odorant transport of 3 different odorants in the nasal cavity was simulated based on the computed steady airflow field. Total airflow significantly increased following bilateral MTR in all patient models ( P < .05). Consistent with our airflow results, we found a decrease in nasal resistance following MTR. MTR significantly increased area averaged flux to the olfactory cleft when compared to controls for phenylethyl alcohol (high-sorptive odorant). Results for carvone (medium sorptive) were similarly elevated. MTR impact on limonene, a low flux odorant, was equivocal. MTR increases nasal airflow while decreasing the nasal resistance. Overall, olfactory flux increased for high sorptive (phenylethyl alcohol) and medium sorpitve (l-carvone) odorants. However, the significant variation observed in one of our models suggests that the effects of MTR on the nasal airflow and the resultant olfaction can vary between individuals based on individual anatomic differences.

Volumetric Airway Analysis Following Maxillomandibular Advancement Surgery for the Treatment of Obstructive Sleep Apnea: Preliminary Results

Maxillomandibular advancement surgery (MMA) is a well-established treatment option for patients with moderate to severe OSA1,2. The primary objective of this prospective study is to quantify pharyngeal airway volume changes in patients who have undergone MMA surgery for treatment of OSA, and determine the relationship between airway changes and changes to the post-operative Apnea-Hypopnea Index (AHI).

Three-dimensional evaluation of changes in upper airway volume in growing skeletal Class II patients following mandibular advancement treatment with functional orthopedic appliances.

The aim of this study was to assess three-dimensionally the upper airway changes following functional appliance treatment in growing Class II patients. Pre-and post-treatment Cone beam computed tomography scans of 20 patients (age range: 9 to 12; mean: 11.4 ± 1.0 years) were retrieved from the list of patients previously treated with functional appliances in the Postgraduate Clinic at the Section of Orthodontics, Aarhus University, Denmark. Total and partial volumes of the upper airway (ie, lower nasopharynx, velopharynx, and oropharynx) were calculated. To rule out the effect of growth, the changes in the functional appliance group were compared to an age-matched Class I group of 18 patients (age range: 8 to 14; mean: 11.8 ± 1.4 years). In the functional appliance group, all the partial and total volumes were significantly larger at the end of treatment when compared to the start of treatment ( P < .003). On the other hand, when comparing the changes for the total and partial volumes of the upper airway in the functional appliance group with the Class I group, a statistical difference was seen only for the oropharynx ( P = .022) and total volume ( P = .025), with the functional appliance group showing a larger volume increment. An increase in the upper airway volume was found after treatment with functional appliances. This difference was mainly related to the changes at the oropharynx level, which differed significantly from what was observed in the Class I group.

Three-Dimensional Analysis of Airway Change After LeFort III Midface Advancement With Distraction.

LeFort III midface advancement using the distraction technique became the standard method for the correction of various craniofacial syndromes accompanied by the midface retrusion. Midface hypoplasia is known to be related to the imbalance in facial aesthetics, malocclusion, and the airway problem. This study aimed to evaluate the change in airway volume after performing a LeFort III midface advancement with the distraction techniques. Between April 2008 and February 2013, 7 patients aged 5 to 7 years underwent standard LeFort III osteotomy, followed by distraction with a rigid external distractor with or without internal distractor. The degree of advancement of the midface and the airway volume were evaluated with 3-dimensional computed tomography scans and the 3-dimensional software. The average latent period was 3.57 days. The average manual distraction distance was 17.55 mm for 3.82 weeks. The consolidation period ranged from 3 to 7 months. Changes between the preoperative and postoperative airway volumes were remarkable. The average preoperative postpharyngeal airway volume was 5649.33 mm compared with an average postoperative airway volume of 7403.44 mm. Therefore, the average postpharyngeal airway space increased by a remarkable 32.78%. This investigation revealed that the LeFort III midface advancement using distraction could increase postpharyngeal airway space by approximately 33% when the midface is advanced by approximately 18 mm. This method could be used as a future reference for LeFort III midface advancement with distraction.

Airway Volume Simulation in Virtual Mandibular Distraction: A Cohort Study.

The authors investigated the accuracy of virtual surgical planning in predicting airway volume changes after mandibular distraction in patients with Pierre Robin sequence and associated tongue-based airway obstruction. The authors completed a single-institution retrospective review of patients for whom virtual surgical planning was used during mandibular distraction osteogenesis for treatment of tongue-based airway obstruction. Preoperative airway volume, virtual surgical planning-predicted airway volume, and postoperative airway volume were calculated from three-dimensional computed tomographic scans using industry software. A blinded institutional radiologist also calculated pre- and post-operative airway volumes. Pre- and post-operative polysomnography was used to titrate the endpoint of mandibular lengthening. Eleven patients were included in the study. Mean apnea-hypopnea index (5.42 ± 4.53 versus 44.96 ± 20.57; p < 0.001) and mean nadir oxygen saturation (70.3 ± 9.72 percent versus 82.9 ± 9.62 percent; p = 0.003) improved with mandibular distraction. There was moderate correlation between predicted and actual mandibular distraction lengths (R = 0.65; p = 0.003). There was a strong correlation between predicted and industry-calculated actual post-distraction airway volume (R = 0.99; p < 0.001). There was no significant correlation between actual mandibular distraction length and industry-calculated actual post-distraction airway volume for the entire cohort (R = 0.05; p = 0.49), but correlation approached significance by institutional calculations. No significant correlation existed between industry and institutional-calculated percentage change in post-distraction airway volume (R = 0.06; p = 0.57). Predictive airway volume calculation may be an effective adjunct to determine anatomic endpoint of mandibular distraction but small sample size, operator and software variability, and patient airway morphology may confound firm conclusions. Further studies are warranted.

Three-dimensional evaluation of airway volume changes in two expansion activation protocols

The purpose of this study was to evaluate the airway volume changes associated with rapid maxillary expansion (RME) protocols using different activation rates. A sample of forty RME treated cases was classified into two groups according to the rate of RME activation (Group A: 0.8mm per day and Group B: 0.5mm per day). Three-dimensional images were obtained for each case before and three months after expansion. Dolphin imaging software was used to identify landmarks and calculate airway volumes. Intraclass correlation coefficient was used to confirm reliability and Wilcoxon signed rank tests were used for comparison between the initial and final measurements within each group and between groups. Significant increase in the nasal cavity volume for both groups was observed (P<0.0001 and P=0.001 for groups A and B respectively). The increase in nasopharynx volume was significant in the group with a more rapid activation rate (P=0.0006). Significant differences between the two groups in post-treatment changes were detected in the nasal cavity volume (P<0.0001), nasopharynx volume (P=0.0035), and soft palate area (P=0.0081). A more rapid activation rate results in a higher volume increase for the nasal cavity and nasopharynx than a slower activation rate.

Quantification of volumetric, surface area and linear airway changes after orthognathic surgery: a preliminary study.

PurposeThe aim of this study was to conduct a retrospective evaluation of the volumetric, cross-sectional surface area and the linear airway changes in healthy subjects undergoing orthognathic surgery.Materials and methodsA total of 10 patients were included in this study and categorized into two groups. The first group consisted of five patients who underwent maxillary and mandibular advancements (MMA) with genioplasty. The remaining five patients who underwent maxillary advancement with mandibular setback (MAMS) comprised the second group. The changes in airway volume, surface area, and linear values obtained from defined hard and soft tissue parameters were evaluated using preoperative and postoperative cone-beam computed tomography. A paired t-test was used to explore the statistical significance.ResultsA statistically significant increase in the airway volume (34.3%) was observed in the MMA group. The changes in the MAMS group were not statistically significant, although an average volumetric decrease of 8.8% was observed. The minimal axial surface area measurements in the MMA group at the levels of the soft palate and the tongue were significantly increased (56.8% and 44.9%, respectively). However, MAMS resulted in no significant changes at these levels (11.2% and 9.1% decrease, respectively). Linear changes showed a statistically significant increase in the airway in the MMA group, whereas the same measurements failed to produce significant changes in the MAMS group.ConclusionAs there were no significant changes in the measured parameters, surgeons can have greater confidence that MAMS does not have any negative influence on the airway.

Effects of unilateral vertical mandibular distraction osteogenesis on airway anatomy in children with hemifacial microsomia

PurposeTo assess the two- and three-dimensional airway changes following unilateral vertical mandibular distraction osteogenesis (vMDO) in patients with hemifacial microsomia (HFM). MethodsA retrospective evaluation was performed for consecutive patients over an 18-month period with HFM and with Kaban-Pruzansky Type-II mandibular deformities who underwent unilateral vMDO for correction of vertical mandibular asymmetry. Patients with complete records and a minimum of 12 months of clinical follow-up post-consolidation were included. Pre-operative airway dimensions (diameters, cross-sectional areas, and volumes) were measured for the oropharynx and nasopharynx. Pre-operative airway dimensions were compared to post-distraction measurements taken from 3D-CT data obtained at a minimum of 3 months post-consolidation. ResultsFive patients met inclusion criteria. Median age was 12.6 years, 3 were female, and median distraction length was 21.3 mm. Median final follow-up CT was performed 5 months after completion of distraction. There were no major or minor complications. Median total airway volume change was +33.7%, corresponding to median volume changes of 80.5% and 10.5% for the oropharyngeal and nasopharyngeal airways, respectively. ConclusionUnilateral vMDO expands the minimum diameter and volume of the oropharyngeal to a greater extent than the nasopharyngeal airway in HFM patients with Kaban-Pruzansky Type-II mandibular deformities.