Airway Space Research Articles

Influence of Fixed Orthodontic Therapy on Pharyngeal Airway Dimensions after Correction of Class-I, -II and -III Skeletal Profiles in Adolescents.

The aim was to compare the influence of fixed orthodontic therapy (OT) on the pharyngeal airway space dimensions after correction of class-I, -II and -III skeletal profiles and among untreated adolescent patients. A control group comprising of untreated patients was also included. Demographics and OT-related information was retrieved from patients’ records. Measurements of airway spaces in the nasopharynx, oropharynx and hypopharynx were performed on lateral cephalograms. p-values under 0.05 were considered statistically significant. The results showed no statistically significant differences in the naso-, oro- and hypo-pharyngeal airway spaces among patients with class-I, -II and -III skeletal profiles and individuals in the control group. There were no statistically significant differences when naso-, oro- and hypo-pharyngeal airway spaces were compared among patients with class-I, -II and -III skeletal profiles. In conclusion, in non-extraction cases without maxillary expansion, fixed OT does not affect the naso-, oro- and hypo-pharyngeal airway spaces in patients with skeletal Class-I, -II and -III skeletal profiles. Further studies involving patients undergoing ME and premolar extraction are needed to elucidate the influence of fixed OT on the naso-, oro- and hypo-pharyngeal airway spaces.

Immediate three-dimensional changes in the oropharynx after different mandibular advancements in counterclockwise rotation orthognathic planning.

BackgroundA retrospective cohort study was performed to evaluate the immediate effect on the oropharynx dimensions from different mandibular advancements in patients undergone counterclockwise rotation (CCW) of the maxillomandibular complex. Material and Methods138 CBCT images of patients, who had undergone orthognathic surgery, were identified from Dolphin Imaging archive according to pre- (T0) and post-operative (T1) times. Each pre-operative CBCT image was selected considering retrognathic mandible. Superimpositions of CBCT images were performed to measure mandibular advancement at B point in millimeters (mm) and divided into three groups: G1 (< 5 mm), G2 (between 5 and 10 mm) and G3 (> 10 mm). For evaluating oropharynx dimension at T0 and T1 for each group, medial sagittal area (MSA), volume, and minimum cross-sectional axial area (CSA) were measured on Dolphin Imaging. Pearson correlation verified reliability of method. Paired t-test were applied to compare values of measurements between T0 and T1 (p ≤ 0.05). Results88 CBCT images were included. Method was reliable (r ≥ 0.93). According to MSA, volume and CSA values from G1, there was no significant difference between T0 and T1. CSA values presented significant difference comparing T0 and T1 in G2 (p ≤ 0.05). In subjects of G3, measurements increased in T1 significantly affecting oropharynx dimension. ConclusionsMSA, volume and CSA values showed a significant increase affecting upper airway in advancements higher than 10 mm. Mandibular advancement range showed different effects in the airway space and should be considered to achieve favorable post-operative results in the oropharynx dimensions. Key words:Retrognathia, orthognathic surgery, three-dimensional imaging, oropharynx, airway.

Three-dimensional pharyngeal airway space changes after bimaxillary advancement.

ABSTRACTIntroduction: The probability of improvement in the upper airway space (UAS) with orthognathic surgery should be considered during the surgical-orthodontic treatment decision, providing not only an esthetic, but also a functional benefit for the patient. Objective: The purpose of this study was to evaluate the 3D changes in the upper airway space after maxillomandibular advancement surgery (MMA). Methods: A retrospective analysis of 56 patients, 21 male and 35 female, with a mean age of 35.8 ± 10.7 years, who underwent MMA was performed. Pre- and postoperative cone-beam computed tomography scans (CBCT) were obtained for each patient, and the changes in the UAS were compared using Dolphin Imaging 11.7 software. Two parameters of the pharyngeal airway space (PAS) were measured: airway volume (AV) and minimum axial area (MAA). Paired t-test was used to compare the data between T0 and T1, at 5% significance level. Results: There was a statistically significant increase in the UAS. Bimaxillary advancement surgery increased the AV and the MAA, on average, by 73.6 ± 74.75% and 113.5 ± 123.87%, respectively. Conclusion: MMA surgery tends to cause significant increase in the UAS; however, this increase is largely variable.

A study to compare nasopharyngeal airway space in skeletal Class I, Class II, and Class III malocclusion

Background: Studies in the past have assessed relation between airway and type of malocclusion and found no association between rhinomanometric measures of airway adequacy and type of malocclusion or craniofacial morphology. Hence, the present study was undertaken to test whether there is any association between pharyngeal airway and type of malocclusion. Methodology: The subjects were divided into 3 groups based on skeletal pattern with 20 subjects in each group: Group 1 with Class I skeletal pattern, Group 2 with Class II skeletal pattern, and Group 3 with Class III skeletal pattern. All the cephalograms were taken in natural head position. Results: There is no significant difference found in total nasopharyngeal area between 3 groups. However, aerial area was significantly reduced in Group 3 (398.4 mm2) than that of Group 2 (485.737 mm2) (P = 0.012). Whereas, significant reduction in adenoidal area was observed in Group 2 (184.021 mm2) when compared with that of Group 3 (286.183 mm2). Conclusion: There was no statistically significant relationship between different skeletal groups and nasopharyngeal soft-tissue characteristics, except for two measurements i.e. aerial and adenoidal area of Group 2 and Group 3.

Controversies in the management of temporomandibular joint ankylosis using distraction osteogenesis - A systematic review

Background:The three commonly employed sequences of distraction osteogenesis (DO) in the management of temporomandibular joint (TMJ) ankylosis with dentofacial deformities include post-arthroplastic distraction osteogenesis (PAD), simultaneous arthroplastic distraction osteogenesis (SAD), and pre-arthroplastic distraction osteogenesis (PrAD).Objective:The aim of this systematic review is to compare the effectiveness of various sequences of DO in the management of TMJ ankylosis with micrognathia/and obstructive sleep apnea syndrome (OSAS).Data Sources:A comprehensive online and manual search of English language literature with no date restrictions was done on March 2020.Eligibility Criteria:Inclusion criteria were case series and prospective and retrospective studies involving adult/paediatric human subjects with unilateral/bilateral TMJ ankylosis and micrognathia/OSAS treated with DO.Study Appraisal and Synthesis Methods:Of 73 studies identified, only 10 were included in the qualitative synthesis. The outcomes assessed were as follows: maximum mouth opening (MMO), posterior airway space (PAS), polysomnography variables, reankylosis, mandibular length, and chin and mandible position.Results:All the included studies showed high risk of bias. MMO and mandibular length increased, chin and mandibular position improved by the end of treatment in all the three sequences, and polysomnography variables and PAS significantly improved in PrAD compared to PAD and improved in SAD compared to baseline. Reankylosis was significantly less in PrAD.Conclusion:More well-designed studies comparing the three sequences of DO should be carried out to arrive at a consensus.

A study to measure nasopharyngeal airway space in different facial morphological patterns between both genders

Background: Studies in the past have assessed relation between airway and type of malocclusion and found no association between rhinomanometric measures of airway adequacy and type of malocclusion or craniofacial morphology. Hence, the present study was undertaken to test whether there is any association between pharyngeal airway and type of malocclusion. Materials and Methods: The subjects were divided into three groups based on skeletal pattern with 20 subjects in each group: Group 1 with Class I skeletal pattern, Group 2 with Class II skeletal pattern, and Group 3 with Class III skeletal pattern. All the cephalograms were taken in natural head position. Results: When compared between males and females among these groups, significant differences were observed in Group 1 in the following parameters: lower airway thickness (PNS-Ba), upper airway thickness (PNS-AD2), and upper airway thickness (PNS-H), and the total nasopharyngeal area was more in males than in females and differences were statistically significant. Conclusion: It was concluded that significant differences were observed in Group 1 in the following parameters: lower airway thickness (PNS-Ba), upper airway thickness (PNS-AD2), and upper airway thickness (PNS-H), and the total nasopharyngeal area was more in males than in females and differences were statistically significant.

Association of sleep disturbances and craniofacial characteristics in children with class ii malocclusion: An evaluative study.

Behaviour problems, poor academic performance and failure to thrive are some of the potential sequelae of sleep problems in children. Hence, there is a need to evaluate the prevalence of sleep problems and significant associations in children with skeletal class II malocclusion with mandibular retrognathism. This study aimed to determine associations if any between sleep practices and problems and craniofacial characteristics in children with skeletal class II malocclusion with mandibular deficiency. A cross-sectional study was conducted among a group of children with skeletal class II malocclusion with mandibular retrognathism. Fifty children aged 8-14 years with skeletal class II with mandibular retrognathism and who required myofunctional therapy were selected. A validated sleep questionnaire assessed the sleep practices and problems. A detailed clinical examination including tonsils and evaluation for mouth breathing was performed. A lateral cephalogram recorded specific linear, angular variables as well as upper and lower pharyngeal airway space. Descriptive statistics, frequency, and percentages were calculated, and the Chi-square test was used. All children reported at least one sleep problem, with snoring reported by 76% of the children. Forty-two percent of the children showed a decreased upper airway, whereas 80% showed a decreased lower airway. Significant associations were seen between SN-MP and noisy breathing, upper airway, and snoring with a P value of 0.017. We also found significant associations between upper and lower airway and sleep positions with a P value of 0.021 and 0.005, respectively. All the children exhibited at least one sleep problem. There was a strong association of certain sleep practices and sleep problems with cephalometric variables.

Upper airway changes following high oblique sagittal split osteotomy (HSSO)

The aim of this study was to evaluate volumetric changes of the posterior airway space (PAS) following bimaxillary surgery using a high oblique sagittal split osteotomy (HSSO) of the mandibular ramus.The cone beam CTs of Class II and Class III patients taken before (T0) and 6–12 months after surgery (T1) were analyzed using 3D software (Mimics® Innovation Suite 18.0). The PAS was divided into three segments (superior, middle, inferior) by three planes parallel to the Frankfurt horizontal plane intersecting at the posterior nasal spine, the velum palatinum and the epiglottis. Total (TPAS) and partial volumes (SPAS = superior, MPAS = middle, IPAS = inferior) were calculated.For the 25 Class II patients, a highly significant increase (p<0.001) of the total, middle and inferior airway space (TPAS: +33.6%, MPAS: +43.1%, IPAS: +55.9%) was found, while the increase of the upper airway space was statistically not significant (+5.4%, p = 0.074). For the 28 Class III patients, the total, middle and inferior airway space increased statistically insignificantly (TPAS: +4.6%, p = 0.265, MPAS: +2.7%, p = 0.387, IPAS: +2.8%, p = 0.495), while the increase of the upper airway space was statistically significant (+9.7%, p = 0.010).Bimaxillary orthognathic surgery using the HSSO technique led to a significant increase of PAS for Class II patients and could conserve the PAS for Class III patients.

A case of extreme skeletal class III Malocclusion beyond the envelope of discrepancy, managed effectively by a modified ortho-surgical protocol

Correction of severe anteroposterior skeletal discrepancy, as described in this case of Extreme Skeletal Class III Malocclusion, can be challenging and fraught with difficulties. Conventional, single stage Bi-jaw Orthognathic surgery, with pre-and post-surgical orthodontics is associated with drawbacks such as risk of relapse and an unsatisfactory outcome, with persisting occlusal discrepancies and skeletal abnormalities, especially when the magnitude of skeletal correction is large. Excessive mandibular setback restricts tongue space, narrows the posterior airway and pharyngeal spaces, and is prone to relapse from the forward pterygomasseteric pull; while large maxillary advancements are accompanied by wound dehiscence, bone exposure and delayed union at the site of pterygomaxillary disjunction, and risk of relapse due to backward palatopharyngeal pull. Bi-jaw surgeries invariably involve considerable blood loss and prolonged operating time with its attendant anaesthetic risks.These drawbacks may be obviated by employing a two staged protocol of Bi-jaw surgeries allowing a minimum time period of 3 months to elapse between them, which allows the oral and maxillofacial musculature to adapt itself to the new jaw position following the first surgery, thus creating a better and more stable environment for the succeeding one. This reduces the chance of relapse thereafter, and produces more effective and stable long term results. The intervening time period also allows for observation of the repositioned jaw and arch relations achieved, and scrutiny for any positional changes in this post-surgical phase, which thereby allows modifications in the planned surgery of the next jaw, thereby achieving the most ideal final outcome.

Counterclockwise Rotational Orthognathic Surgery for the Obstructive Sleep Apnea in Class II Dentofacial Deformity: Polysomnography and 3D Computed Tomographic Analysis.

Traditionally, maxillomandibular advancement is an orthognathic surgical procedure that has been used to manage obstructive sleep apnea in patients not able or willing to maintain adherence to continuous positive airway pressure therapy or for patient who are not able to adhere to treatment. However, maxillomandibular advancement often leads to unsatisfactory cosmetic results.This prospective study investigated functional and esthetic outcomes using polysomnography and 3-dimensional computed tomography, after counterclockwise rotational orthognathic surgery. We enrolled 17 patients with obstructive sleep apnea, who underwent orthognathic surgery at single institution between March 2013 and December 2018.After 12 months, the patients' mean self-rated score for facial appearance, using a 10-step visual analog scale, was 7.36. The preoperative apnea-hypopnea index and respiratory disturbance index were 34.70 and 37.45, respectively; postoperative indices were 11.60 and to 12.69, respectively (P = 0.003, 0.003). The mean posterior pharyngeal airway space increased from 5357.88 mm3 preoperatively to 8481.94 mm3 after 6 postoperative months.Counterclockwise rotational orthognathic surgery for the correction of obstructive sleep apnea turned out to be the ideal solution not only in the correction of the sleep apnea, but also in the facial esthetics.

Nasopharyngeal airway and subcranial space analysis in Pfeiffer syndrome

Tracheotomy in infancy helps patients with Pfeiffer syndrome to survive by preventing respiratory crisis, but difficulty in decannulation may consequently be a challenge. This study has investigated the regional abnormalities of the nasopharyngeal airway in children with Pfeiffer syndrome to provide an anatomical basis for the surgical treatment and decannulation of the upper airway. Seventy-two preoperative computed tomograms (CT) (Pfeiffer syndrome n=30; control n=42) were included. The airway volume, cross-sectional area, and cephalometrics were measured using Materialise software. Patients with Pfeiffer syndrome developed a 50% (p<0.001) reduction of nasal airway volume, and a 44% (p=0.003) restriction in pharyngeal airway volume. In patients with Pfeiffer syndrome the cross-sectional area at the choana was only half that of the controls (p<0.001). The posterior width of the nasal airway in patients with Pfeiffer syndrome was shortened by 13% (p=0.003), and the height reduced by 21% (p<0.001). The cross-sectional areas at the condylion and gonion levels, which indicate the calibre of the pharyngeal airway at the entrance and midsection, were reduced by 67% (p<0.001) and 47% (p<0.001), respectively, when compared with the controls. The volume of the nasal airway in patients with Pfeiffer syndrome was significantly restricted in length, height, and width, and by choanal stenosis in all cases in this cohort. The reduced anteroposterior length of the nasal airway contributed to the shortened maxilla more than the anteroposterior position. The limited height and width of the nasal pathway was the result of a hypoplastic sphenoid. Restricted mediolateral and anteroposterior dimensions were evident across the entire course of the pharyngeal airway. Mediolateral maxillary expansion in addition to maxillomandibular advancement is therefore likely to benefit these patients.

Does overweight affect the sagittal dimension of the posterior airway space in a non-OSAS population? A case control study.

ObjectiveThe null hypothesis was that, in a non‐obstructive sleep apnea syndrome population, overweight do not reduce the antero‐posterior dimension of the posterior airway space.Materials and MethodsThe author retrospectively reviewed the records of subjects evaluated at the Maxillofacial Surgery Unit, Department of Neurosciences, University of Padova Medical School, Padova, Italy, from 2016 to 2018. Only patients with complete demographic, anthropological and CBCT dataset were enrolled. OSAS patient were also ruled‐out. Enrolled patients were divided into overweight (28 cases) and non‐overweight (32 controls) groups according to the patient's Body Mass Index. Each two‐dimensional cephalometric radiography obtained from the cone‐beam computer tomography dataset was evaluated in order to measure linear and angular distances between standardized cephalometric landmarks. The two‐sample t‐test was the statistical test applied to compare the case and control data.ResultsThere were no statistical differences between the two study groups for any of the evaluated variables: the null hypothesis was accepted.ConclusionThis study showed that in a non‐obstructive sleep‐apnea population, overweight and class I obesity does not influence the airway space in the antero‐posterior dimension. Further investigation should focus on categorized overweight‐obese population. Accurate and reliable protocol for tridimensional airways assessment should be implemented.

Effect of Obstructive Sleep Apnea on Condylar Malformation, Vertebral Column, and Head Posture: A Cephalometric Evaluation.

Aims and objectivesObstructive sleep apnea (OSA) is by far the most common sleep-related breathing disorder, affecting 2–4% of the adult population. The present study aims to compare the descriptive morphology of the cervical column in subjects with normal craniofacial morphology with those having condylar hypoplasia with OSA and to evaluate a positive correlation between the cervical columns, the cranial base angle, and the posture of the head and neck in subjects of condylar hypoplasia.Materials and methodsThe present study comprised of lateral cephalogram of 40 subjects divided into two equal groups—control groups (n = 20) and OSA with condylar hypoplasia (n = 20).Results and observationThe condylar hypoplasia group has fusion anomalies of 65% and 35% has a posterior arch deficiency. The cervical lordosis, inclination of the cervical column is found to have a positive statistically significant correlation in condylar hypoplasia subjects.ConclusionMorphological deviations and deviation pattern of the cervical column occurred significantly more often in subjects with condylar hypoplasia as compared with normal craniofacial morphology which can be verified by the increased cranial base angle, cervical lordosis, the inclination of the upper cervical spine, and cranial base angle were positively correlated with a fusion of cervical column.Clinical significanceSpecific types of craniofacial morphology and head postures such as a reduced posterior airway space, an abnormally long soft palate, a low position of the hyoid bone, and an extended head posture are considered predisposing factors of OSA. As posture of the head and neck is considered to be associated with OSA, OSA may be associated with fusion of the cervical column. Hence, to know the result of malformation in the cervical column prove to be important with regard to phenotypical subdivision, diagnosis, and treatment of OSA.How to cite this articleDivya, Navit P, Singh R, et al. Effect of Obstructive Sleep Apnea on Condylar Malformation, Vertebral Column, and Head Posture: A Cephalometric Evaluation. Int J Clin Pediatr Dent 2020;13(S-1):S64–S68.

The investigation of pharyngeal airway space by cephalogram landmarks in primary school children in Taiwan

Background/purposeProper breathing is essential to healthy growth and development of children. The present study aimed to investigate changes in the pharyngeal airway space in primary-school children. Materials and methodsCephalometric radiographs were obtained from 93 primary-school children, who were divided into three age groups (Group I, aged 7–8 years; Group II, aged 9–10 years; and Group III, aged 11–12 years). Landmarks identified on each cephalogram included the tip of the uvula (U), hyoid bone (H), and epiglottis (E). Linear and angular measurements comprised nasopharyngeal airway (NP); PS (shortest distance from the soft palate to the pharyngeal wall); UP (distance from the tip of the uvula to the pharyngeal wall); TS (shortest distance from the posterior tongue to the pharyngeal wall); EP (distance, parallel to the X-axis, from the epiglottis to the pharyngeal wall). Statistical analysis was performed using one-way analysis of variance and Pearson correlation tests. ResultsGroup III had the highest values for all the variables. The three groups exhibited significant differences for all pharyngeal airway variables, except for EP. The three groups had significantly different vertical U, H, and E. There were positive correlations between age and NP, PS, UP, and TS; however, no significant correlation was observed between age and EP. Age significantly correlated with the vertical U, E, and H. Correlations between age and the horizontal U, E, and H were nonsignificant. ConclusionAmong primary-school children from various grades, age significantly correlated with all pharyngeal airway variables, except with EP.

Correlation between Malocclusion and Allergic Rhinitis in Pediatric Patients: A Systematic Review.

Background: Oral breathing, nasal obstruction and airway space reduction are usually reported as associated to allergic rhinitis. They have been linked to altered facial patterns and dento-skeletal changes. However, no firm correlation based on the evidence has been established. This systematic review has been undertaken to evaluate the available evidence between malocclusion and allergic rhinitis in pediatric patients. Methods: The research refers to Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines, databases (Medline, Cochrane Library, Pubmed, Embase and Google Scholar) were screened, the quality was evaluated through Quality Assessment of Diagnosfic Accuracy Studies (QUADAS-2). Results: The articles selected (6 out of initial 1782) were divided on the basis of the study design: two observational randomized study, three case–control study, one descriptive cross-sectional study, and one longitudinal study. A total of 2188 patients were considered. Different results were reported as related to allergic rhinitis ranging from a higher incidence of dental malocclusion, to an increase of palatal depth, and in posterior cross-bite about anterior open-bite and to longer faces and shorter maxillas. Conclusions: Most of the studies selected found a rise in the prevalence of both malocclusion and allergic rhinitis in children. However, the level of bias is high, impaired by a poor design and no conclusive evidence can be drawn.

Correlation Between Pharyngeal Airway Space and Sagittal Skeletal Malocclusions

OBJECTIVE: To determine correlation between pharyngeal airway space and sagittal skeletal malocclusions. METHODOLOGY: Data was collected using pre-treatment records including pre-treatment lateral cephalograms of 54 orthodontic patients. Patients from both gender were included. The age group of selected patients was 15-25 years, Patients belonging to Pakistani ethnicity were included to avoid selection bias. Sagittal skeletal malocclusion was measured by ANB angle to group the skeletal Class I, II and III subjects (ANB=0-4°, ANB &gt; 4° and ANB &lt;0 respectively). Upper pharyngeal space and Lower Pharyngeal space was measured. This cross sectional study was conducted in Orthodontic OPD at Karachi Medical and Dental College, from August 2019 to March 2020. RESULTS: The obtained data showed strong negative correlation between ANB angle and upper pharyngeal space whereas moderately negative correlation between ANB angle and lower pharyngeal space. CONCLUSION: Upper and lower pharyngeal widths were influenced by Sagittal malocclusion. KEYWORDS: Pharyngeal airway space, Sagittal skeletal malocclusion, Obstructive sleep apnea, Sleep disordered breathing, ANB. HOW TO CITE: Siddiqui H, Rizwan S, Faisal SS, Hussain SS. Correlation between pharyngeal airway space and sagittal skeletal malocclusions. J Pak Dent Assoc 2020;29(4):217-222.

The interaction of obesity and craniofacial deformity in obstructive sleep apnea.

Both obesity and craniofacial deformity are important etiologies of obstructive sleep apnea (OSA). The present research aimed to explore their interaction and different impacts on OSA severity. A total of 207 consecutive OSA patients (169 males, 38 females) were included in the research. Based on the body mass index (BMI) value, patients were divided into 77 normal-weight patients (BMI <24 kg m-2), 105 overweight patients (24 ≤ BMI<28 kg m-2) and 26 obese patients (BMI ≥28 kg m-2). All accepted overnight polysomnography and standard lateral cephalogram. Cephalometric measurements involved 25 cephalometric variables. The correlations between these cephalometric variables, BMI and the apnea-hypopnea index (AHI) were evaluated. For the whole sample after controlling for gender and age, stepwise regression analysis showed that the factors affecting AHI were increased BMI, narrowing posterior airway space, inferior displacement of hyoid and elongation of the tongue. When grouped by BMI, normal-weight group exhibited with more reduced maxillary length and mandible length, and steeper mandible plane than overweight and obese patients (p < 0.0167). Obese group showed least skeletal restriction and most prominent soft tissues enlargement (p < 0.0167). However, these skeletal indexes were not statistically correlated with AHI. Obesity and skeletal malformations were both etiological factors of OSA, but obesity seemed to have a greater influence on AHI severity in all kinds of obese and thin OSA patients. Only in normal-weight group, it was affected by both cephalometric variables and BMI.

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.

The Bioadaptive Changes in the Pharyngeal Airway and Hyoid Position Following Mandibular Setback Surgery: A Cephalometric Study

Objective: Patients who underwent bilateral sagittal split osteotomy with mandibular setback had been evaluated using lateral cephalograms to identify sites of mechanical obstruction that predispose to airway obstruction. The bioadaptive changes that occur in the peri-airway structures in the post-operative period were evaluated. Methods: The hard and soft tissue landmarks used in cephalometry were used to trace and measure the pharyngeal airway space (PAS) and changes in position of hyoid. Amount of mandibular setback, PAS width, PAS area and changes in the hyoid position were recorded. The difference in pre- and post-operative values measured from cephalometric tracings were analyzed statistically using repeated measure ANOVA. Results: The results demonstrated a significant reduction in PAS width and area corresponding to the decrease in length of mandible after BSSO setback. The decrease in PAS width was found to be 41% of the amount of mandibular setback at 6 months. The mean mandibular setback recorded at 6 months was 8.2 mm. The mean reduction in PAS width registered at 3 and 6 months were 3.8 mm and 3.4 mm (p value 0.001),marginally reclaiming the PAS width at 6 months. The mean reduction in PAS area at 3 and 6 months were 1.6 cm2 and 2.1cm2 (p value 0.009) demonstrating no recovery in the PAS area. The hyoid was displaced posteriorly and inferiorly; the mean displacements in the posterior direction at 3 and 6 months were 2.6 mm and 2 mm (p value 0.013) and inferior direction were 3 mm and 4 mm. Conclusion: Mandibular setback surgery has the potential for narrowing the pharyngeal airway space with a significant reduction in PAS width and area, that could predispose to OSA. The results demonstrate that bioadaptive changes of the hyoid are greater post-surgery and tend to settle in the direction of its pre-surgical position in the anteroposterior plane and drift inferiorly in the supero-inferior plane in an attempt to restore the airway space.

Quantifying Upper Airway Changes Following Mandibular Orthognathic Surgery.

The aim of this study was to quantify upper airway changes following mandibular orthognathic surgery. Treatment records of 50 patients who underwent mandibular orthognathic surgery were divided into 2 groups, that is, Group 1: Cases treated with Mandibular Advancement Surgery and Group 2: Cases treated with Mandibular Setback Surgery with 25 patients in each group. The Lateral Cephalogram and Acoustic Pharyngometry records of both groups were studied at T0 (01 week before surgery) and T1 (01 year postsurgery) for changes in linear airway measurements (Nasopharyngeal Airway Space - NAS, Superior Airway Space - SAS, Posterior Airway Space - PAS and Hypopharyngeal Airway Space (HAS)), hyoid bone position (Mandibular Plane Hyoid distance), mean area and mean volume. The percentage change and change in these parameters per millimeter advancement or setback of mandible at T1 was calculated. A significant increase in linear airway parameters (SAS and PAS); decrease in hyoid distance; and increase in volume and area of upper airway was observed at T1 in Group 1 and reverse was observed in Group 2. The change in airway parameters (SAS, PAS, mean volume and area) was more significant in Group 1 as compared to Group 2. In the current airway centric approach, meticulous assessment and prediction of long-term airway changes post surgery should be an integral part of ortho-surgical diagnosis and treatment planning and suitable modifications in the treatment plan must be made to cater for any potential adverse effects on airway.