Pharyngeal Airway Space Research Articles

Clustering-based characterization of clinical phenotypes in obstructive sleep apnoea using severity, obesity, and craniofacial pattern

To identify and characterize the phenotypes of adult obstructive sleep apnoea (OSA) patients based on clustering using OSA severity, obesity, and craniofacial pattern. The samples consisted of 89 adult OSA patients whose polysomnography and lateral cephalogram were available. With cluster analysis using apneahypopnea index (AHI, events/hour), body mass index (BMI, kg/m2), ANB (degree), and mandibular plane angle (MPA, degree), three clusters were identified. Cephalometric variables including craniofacial, soft palate, hyoid bone, and pharyngeal space compartments were compared among clusters by one-way analysis of variance or Kruskal-Wallis test. Multivariable linear regression analysis was performed to find contributing factors to OSA severity within each cluster. Cluster-1 (obesity type; 49.4 per cent) exhibited moderate OSA, obesity, and normal sagittal and vertical skeletal pattern (AHI, 22.4; BMI, 25.5; ANB, 3.2 degrees; MPA, 26.3 degrees) without significant upper airway abnormality. Cluster-2 (skeletal type; 33.7 per cent) was characterized by moderate OSA, severe skeletal Class II hyperdivergent pattern with narrow pharyngeal airway spaces, without obesity (AHI, 27.9; BMI, 23.5; ANB, 7.5 degrees; MPA, 36.6 degrees). Cluster-3 (complex type; 16.8 per cent) included severe OSA, obesity, skeletal Class II hyperdivergent pattern (AHI, 52.8; BMI, 28.0; ANB, 4.5 degrees; MPA, 32.2 degrees), with posteriorly displaced hyoid and retroclined soft palate. The main contributing factors to AHI were obesity in Cluster-1; hyperdivergent vertical pattern with narrow pharyngeal space in Cluster-2; and hyperdivergent pattern, obesity, displaced hyoid, and soft palate in Cluster-3. Three OSA phenotypes resulted from this study provide a clinical guideline for differential diagnosis and orthodontic intervention in the interdisciplinary treatment for OSA patients.

Computed tomography visualizing alterations in the upper airway after orthognathic surgery

Three-dimensional (3D) software has revolutionized planning in orthognathic surgery. This technology allows the simulation of surgical movements and evaluation of the volume and area of the pharyngeal airway space (PAS), which are not possible with two-dimensional (2D) software. Many patients undergo orthognathic surgery to improve occlusion and facial profile. The PAS may increase or decrease depending on the surgical movements. This study aimed to evaluate the changes in the area and volume of the PAS in patients having bimaxillary movement in orthognathic surgery. The minimum axial area and volume of the PAS (preoperative (T0) and postoperative (T1) air volumes) of 68 patients (26 male and 42 female, mean age 36.6 ± 12.1 years) were analyzed. Evaluations were conducted using cone-beam computed tomography in the Nemoceph 3D-OS program. A paired t-test was used to compare pre- and postoperative volume data, and the Wilcoxon test was used to compare pre- and postoperative data of the minimal axial area. All the tests were performed with Statistica software (StatSoft Inc., Tulsa, OK, USA), and a significance level of 5% was adopted. In the study of the method error, no casual or systematic error was found between the first and second measurements of the variables (p > 0.05 in all measurements). Bimaxillary surgery presented a mean of 70.46% in volume and a median increase of 61.27% in the minimum axial area, which varied from −22.50% to 659.06%. The results demonstrated that bimaxillary advancement significantly increased the volume and minimum axial area of the upper airway; however, the increase was not homogeneous in all the patients.

Changes in Hyoid Bone Position and Cross-sectional Area of Pharyngeal Airway After Oral Cancer Surgery.

To investigate hyoid bone position and cross-sectional area (CSA) of pharyngeal airway space (PAS) for assessing postoperative airway change after oral cancer surgery with concurrent neck dissection (ND). Fifty-two patients who underwent oral cancer surgery with concurrent ND were retrospectively evaluated by grouping based on ND type and reconstruction. Computed tomographic data were analyzed three-dimensionally before and after surgery. The hyoid bone position differed significantly between preoperative and postoperative images in the anteroposterior and supero-inferior directions (p<0.05). CSA was increased after ND (p<0.05). The hyoid bone was positioned more superiorly in ND and fibular free-flap reconstruction groups compared to other groups (p<0.05). CSA of the PAS increased as the hyoid bone moved forward (p<0.05). The hyoid bone moves forward and upward after oral cancer surgery with concurrent ND, which increases the CSA of the PAS. These results provide the useful insight into managing a patient's airway after oral cancer surgery with ND.

Short-term pharyngeal airway space changes after mandibular advancement surgery in Class II patients-a two-dimensional retrospective study.

Planning successful treatment for the correction of anatomic abnormalities of the upper airways, by surgical advancement of the mandible, depends on extensive knowledge of the pharyngeal airway space (PAS). However, there is limited scientific evidence about changes in PAS after mandibular advancement surgery. To evaluate the immediate changes in superior posterior airway space (SPAS) in Class II patients, after mandibular advancement surgery. A cephalometric evaluation of 37 patients with skeletal Class II deformity was performed at 2 distinct time intervals: Pre-operative (T0) and immediate post-operative (T1), using Dolphin Image & Management Solutions, version 11.9, according to the method of Arnett/Gunson FAB Surgery. The differences due to the surgical intervention were assessed with Student's t test, and a Principal Component Analysis was used to evaluate the relationship between mandibular advancement and SPAS variables. Anticlockwise and clockwise rotation groups were also evaluated with Mann-Whitney tests. The statistical analysis was conducted in SPSS and R assuming a 0.05 level of significance. As an effect of mandibular advancement, an anteroposterior statistically significant increase in SPAS (P<0.001) was perceived at all points measured. Our findings indicate that mandibular advancement surgery is a viable option to achieve widening of the SPAS in patients with Class II skeletal morphology.

Three-dimensional alterations in pharyngeal airspace, soft palate, and hyoid bone of class II and class III patients submitted to bimaxillary orthognathic surgery: A retrospective study

IntroductionThe aim of this retrospective study was to evaluate changes in pharyngeal airway space (PAS), soft palate, and hyoid bone position after bimaxillary orthognathic surgery in skeletal Class II and Class III patients. MethodsPatients were divided into Group 1: Class III patients who underwent maxillary osteotomies and mandibular setback surgery (N = 43); and Group 2: Class II patients who underwent maxillomandibular advancement surgery (N = 36). Cone beam computed tomography (CBCT) images were acquired one month before and six to eight months after orthognathic surgery. PAS area, volume and minimum axial area (MAA), soft-palate morphology, and hyoid bone position measurements obtained before and after orthognathic surgery were compared using the Gamma family test (p ≤ 0.10). ResultsIn Class II group the maxillomandibular advancement surgery significantly increased the PAS area, volume, and MAA and significantly affected hyoid bone position and soft-palate morphology. In Class III group, maxillary osteotomies and mandibular setback also showed increase in PAS area, however without statistically significant values for most of the evaluated measurements. ConclusionThe results of the present study indicate that PAS and related structures are expected to be improved in Class II patients submitted to bimaxillary surgery, and they are not negatively affected by bimaxillary surgery in Class III patients.

Pharyngeal airway spaces in different skeletal malocclusions: a CBCT 3D assessment

ABSTRACT Objective: To three-dimensionally evaluate the upper pharyngeal airway spaces in adults with different anteroposterior and vertical skeletal malocclusions. Methods: In this retrospective study, three-dimensional airway volume and the minimum constricted areas of 120 adults were measured from cone beam computed tomography volume scans. The sample was divided into skeletal Class I and Class II and subdivided into average and long face malocclusions in each skeletal Class. Airway volumes of the naso-, palato-, and glossopharynx, and the minimum constricted area were measured and compared. Results: Skeletal Class II reduced glossopharyngeal airway volume and larger total minimum constricted area in average faces and more nasal minimum constricted area in long faces. Skeletal Class II with long face significantly increased palatopharyngeal and glossopharyngeal airway volumes as well as larger palatopharyngeal minimum constricted area (p < 0.05). Conclusion: This paper found a likely association between jaw skeletal classification and airway dimensions.

Influence of mandibular setback surgery on three-dimensional pharyngeal airway changes

The aim of this study was to investigate the factors influencing three-dimensional changes in pharyngeal airway space after mandibular setback surgery. Airway changes in 48 skeletal class III patients who had undergone mandibular setback surgery alone (n=25, group 1) or with maxillary surgery (n=23, group 2) were analyzed. Linear parameters, cross-sectional area, and volumes of the pharyngeal airway were evaluated before (T0), immediately after (T1), and 1year after surgery (T2) by cone beam computed tomography. Although the reduced airway volume and cross-sectional area recovered slightly in the long term after surgery, the total pharyngeal airway volume (TPV) was significantly reduced compared to baseline, by 15% in group 1 and 12% in group 2. Regression analysis showed that maxillary posterior impaction in two-jaw surgery had a protective effect on preserving TPV. A change in body mass index from T0 to T2 was an important predictor of decreased TPV in one-jaw surgery patients. Maxillary posterior impaction can be a reliable option for compensating the pharyngeal airway reduction after mandibular setback surgery. Postoperative weight gain can increase the risk of postoperative pharyngeal airway reduction. Therefore, these factors need to be considered before and after mandibular setback surgery.

Pharyngeal airway evaluation following isolated surgical mandibular advancement: A 1-year follow-up.

The aim of this study was to evaluate the stability of pharyngeal airway space changes with the use of acoustic pharyngometry 1year after bilateral sagittal split ramus osteotomy for mandibular advancement in patients with skeletal Class II malocclusion. The sample comprised 16 patients (mean age 21.26±1.86years). Acoustic pharyngometry measurements were recorded 1week before surgery (T0), 2months after surgery (T1), and 1year after surgery (T2). Parameters were compared by means of repeated-measures analysis of variance (ANOVA). Significant increase was seen in minimum cross-sectional area 2months after surgery (P<0.001). Relapse of 12.6% was observed within 1year after surgery (P<0.001). Statistically significant increase, ie, 31.5%, was seen in mean cross-sectional area 2months after surgery (P<0.001), which relapsed by 7.9% 1year after surgery (P<0. 0.001). Significant increase in mean volume from 30.32±2.2cm3 before surgery to 38.91±2.73cm3 2months after surgery (P<0.001) was observed. Mean volume relapsed 3.9% 1year after surgery (P<0.001). Changes in pharyngeal airway space dimensions in patients subjected to isolated surgical mandibular advancement on 1year follow up showed encouraging results.

Pharyngeal airway space changes after maxillomandibular advancement: a five-year retrospective study

The aim of this study was to compare the alterations in three regions of the airway—nasopharynx, oropharynx, and hypopharynx—in relation to the area of the midsagittal plane, volume, and minimal axial area after maxillomandibular advancement (MMA) surgery. Thirty patients who had undergone MMA surgery were evaluated at four time points: preoperative (T0), immediately postoperative (T1), 1year postoperative (T2), and ≥5 years postoperative (T3). All measurements were performed using computed tomography, analyzed in Dolphin Imaging 11.0 Premium 3D software. The area in the midsagittal plane presented a mean increase of 22.0% between T0 and T3 (P<0.001), with the highest increase in the oropharynx (24.1%, P<0.001). The total volumetric increase at T3 was 16.7% (P<0.001), with the highest increase in the nasopharynx (15.7%; P<0.001). The lowest minimal axial area was found for the oropharynx at all time points, and the highest increase in minimal axial area was found for the nasopharynx (114.9%; P<0.001). MMA surgery showed the highest increase in upper posterior airway between T0 and T1, and this was followed by a progressive reduction until T3, but with a statistically significant increase at T3 compared with T0 in all cases.

Correlation Between Hyoid Bone and Pharyngeal Airway Space in Differing Vertical Skeletal Dysplasia

The hyoid and the tongue are intimately associated structures. The hyoid bone forms the anterior limit of the pharyngeal airway space. Thus, the position of hyoid bone and position of tongue can be considered determinants of pharyngeal airway space. Sixty samples, divided in three groups based on their growth pattern were studied and McNamara’s airway analysis and hyoid triangle analysis were used to evaluate the pharyngeal airway space and hyoid bone position respectively. A negative correlation was found in hyperdivergent group between the upper and lower airway space and the FMA. A positive correlation was seen in hyperdivergent group between the upper and lower airway space and the anteroposterior position of the hyoid bone.

Cephalometric analysis of the pharyngeal airway space after maxillary advancement surgery.

This study evaluated the effect of maxillary advancement surgery on the size of the pharyngeal airway space (PAS). Lateral cephalometric radiographs were collected for 90 patients (29 men and 61 women; average age, 27.2 ± 8.1 years) before (T1) and 1 year after (T2) maxillary advancement surgery. Horizontal and vertical changes in the maxilla and PAS were measured and classified by distance. The maxilla was advanced horizontally by 2.9 ± 1.7 mm and vertically by 2.7 ± 1.4 mm. Upward maxillary movement of ≥4 mm significantly increased PAS (mean change in PAS, 2.6 mm), and upward maxillary movement significantly decreased the posterior nasal spine to the P-point. Only patients with vertical advancement ≥4 mm and horizontal advancement of 3 mm had significant increases in all three PAS parameters. Although forward maxillary movement is believed to have a large effect on PAS, it is suggest that upward vertical movement is more effective for improving PAS. Both the extent and direction of maxillar movement should be considered. Future studies should use cone-beam computed tomography to evaluate the effect of axial direction and differences in PAS.

Cone-beam evaluation of pharyngeal airway space in adult skeletal Class II patients with different condylar positions.

To test the null hypothesis that there is no significant difference in pharyngeal airway space among adult skeletal Class II patients with different condylar positions using cone-beam computed tomography (CBCT). The CBCT records of 60 patients with skeletal Class II malocclusion (ANB angle ≥ 4°, Wits ≥ 0) were selected from the CBCT database. According to the condyle position, the patients were divided in three groups: anterior group (CD ≤ -12%), centric group (-12% ≤ CD ≤ +12%), and posterior group (CD ≥ +12%). Three-dimensional (3D) pharyngeal airway models were reconstructed using InvivoDental software 5.1.3. The volume and area of the pharyngeal airway space were measured in the 3D airway model. The volume and area of the pharyngeal airway space in the centric group were significantly smaller than those in the posterior group ( P < .01). The volume and area of the pharyngeal airway space were smallest in the anterior group and significantly increased in the centric and posterior groups ( P < .001). The null hypothesis was rejected. Significant differences were noted in pharyngeal airway space among adult skeletal Class II patients with different condylar positions.

Pre-arthroplastic mandibular distraction osteogenesis for the correction of OSA in TMJ ankylosis: a prospective observational study of 25 cases.

In severe TMJ ankylosis cases, the lack of growth of the mandible creates an anatomically narrow airway with a reduced pharyngeal airway space [PAS] which predisposes these patients towards obstructive apnoea [OSA]. There is evidence in the literature that such patients experience severe discomfort during physiotherapy if such airway abnormalities are not corrected prior to ankylosis release. This eventually leads to non-compliance towards physiotherapy and increases the risk of re-ankylosis. In our study, pre-arthroplastic mandibular distraction osteogenesis [DO] was used to increase the PAS and resolve the underlying OSA prior to releasing the ankylosis. Twenty-five cases of TMJ ankylosis with micrognathia and OSA were included in this prospective observational sleep study. They were further divided into a paediatric group [14 subjects] and an adult group [11 subjects]. All cases presented with a history of onset of ankylosis during childhood [before the completion of craniofacial growth] as result of which there was a lack of forward growth of the mandible. Subjects included in our study underwent initial DO of the mandible followed by a second procedure for distractor removal and ankylosis release. Questionnaires, lateral cephalograms and sleep studies were taken pre-operatively (T0), immediate post-distraction to the desired length (T1) and 12months post the distractor removal and ankylosis release (T2). The parameters studied were PAS width, apnoea hypopnea index [AHI], O2 saturation, mouth opening and mandibular advancement. The paediatric group variables were as follows: mean PAS width which increased from 3.5mm [T0] to 9mm [T2], mean AHI which decreased from 48.04 [T0] to 3.60 [T2], mouth opening which increased from 4.5mm [T0] to 34mm [T2] and mean O2 saturation which increased from 89.86% [T1] to 96.88% [T2]. The adult group variables were as follows: mean PAS width which increased from 5mm [T0] to 11mm [T2], mean AHI which decreased from 31.45 [T0] to 1.43 [T2], mouth opening which increased from 5mm [T0] to 34mm [T2] and mean O2 saturation which increased from 92.01% [T0] to 96.84% [T2]. Statistical analysis revealed that DO of the mandible significantly improved OSA by increasing the PAS which was evident by the lower AHI score. Mouth opening was also significantly improved post ankylosis release and maintained at the T2 interval. Ten subjects followed up beyond the T2 interval [mean 28months post ankylosis release] and their data also revealed positive compliance towards physiotherapy, adequate mouth opening and maintenance of normal AHI. Pre-arthroplastic mandibular DO has proved to be a successful modality for treatment of OSA in TMJ ankylosis patients with stable results at 12months. By resolving the narrow airway and OSA, compliance towards physiotherapy was improved thus reducing the risk of re-ankylosis in the long term.

Accuracy of Virtual Surgical Planning in Treatment of Temporomandibular Joint Ankylosis Using Distraction Osteogenesis: Comparison of Planned and Actual Results

This study evaluated the accuracy of virtual surgical planning and 3-dimensional (3D) printed templates to guide osteotomy and distraction osteogenesis (DO) in the treatment of temporomandibular joint (TMJ) ankylosis and secondary mandibular deformity. Seven consecutive patients diagnosed with TMJ ankylosis and mandibular deformities were included. A composite skull model was obtained with data from spiral computed tomography (CT) and laser scanning of the dental arch. A virtual surgical simulation was performed using Dolphin Imaging 11.7 Premium (Dolphin Imaging and Management Solutions, Chatsworth, CA). Then, the virtual plan was transferred to the operation using 2 surgical templates. These templates were designed by 3D printing using data from the virtual surgical simulation for guiding the osteotomy and the DO, respectively. The preoperative measurement and differences between the actual mandibular position and the virtual plan were analyzed. Postoperative radiographs, CT images, and quantitative analysis showed a clinically acceptable precision for the position of the mandible. The mean length of the mandible and the vertical height of the DO were 79.1 and 14.9mm, respectively. With the 3D superimposition and linear measurement, the mean difference between the virtual plan and the actual results ranged from 0.64±0.20 to 1.90±0.85mm. Allpatients obtained satisfactory changes in the facial profile and marked improvement in postoperative pharyngeal airway space and mouth opening. The results of this study showed that virtual surgical planning and 3D printed guiding templates facilitated treatment planning, an accurate osteotomy, repositioning of bony segments, and contouring of the mandibular border in the treatment of TMJ ankylosis and secondary mandibular deformity.

Volumetric analysis of total pharyngeal airway space using cone beam computed tomography among adult egyptians

A typical airway is needed for typical improvement of the craniofacial structures. The objective of the research was to; analyse and contrast the pharyngeal airway volume in the class I and class II facial skeletal patterns using cone beam computed tomography. Methods: The present retrospective study was led on 80 cone beam computed tomography (CBCT) records of adult egyptians ranging in age from 20-40 years. The records were equally divided into 2 groups; group I (G1) skeletal class I ANB =1°-4°), (group II, skeletal class II (G2) ANB >4°). Evaluation of the pharyngeal air way space volume was conducted and statistically analyzed to contrast between G1 and G2 Results: Statistically significant distinctions was found on total pharyngea1 airway volume between G1&G2 Conclusion: The entire volume of pharyngea1 airway space was much larger in G1 than G2 subjects.

Effects of rapid palatal expansion (RPE) and twin block mandibular advancement device (MAD) on pharyngeal structures in Class II pediatric patients from Cluj-Napoca, Romania

Objective: To compare cephalometric changes of pharyngeal structures after rapid palatal expansion (RPE) with those induced by a twin block mandibular advancement device (MAD) with palatal expansion capability. Methods: This retrospective study investigated 55 Class II pediatric patients, divided into two groups: 29 patients treated with RPE and 26 patients treated with MAD. Lateral cephalometric measurements were compared before and after treatment. Results: Changes in pharyngeal airway space were statistically significant in both groups (p < 0.001) from a pre-treatment mean distance measured between the lower posterior pharyngeal wall and the hyoid bone (LPF-H) of 25.42 mm in the MAD group and 28.62 mm in the RPE group, to a post-treatment mean LPF-H of 27.96 mm in the MAD group and 31.52 mm in the RPE group. Conclusion: Significant changes in pharyngeal space may be obtained in Class II patients through both rapid palatal expansion and mandibular advancement devices with palatal expansion capability.

The long-term effect analysis of the tongue base traction/ hyoid suspension with Repose system in multiplanar surgery

Objective:To explore the long-term effect of Repose bone screw system in the treatment of severe obstructive sleep apnea syndrome in patients with severe obstructive sleep apnea. Method:The follow-up group was divided into the short-term (<12 months, control group, 30 cases) and the long-term (more than 12 months, observation, 46 cases). And compared the operation effect of the two groups. Furthermore, the parameters and related factors of surgical efficacy of patients with different follow-up time and different surgical methods were further analyzed.Result:①There was no statistical difference in the preoperative parameters of the two groups, and the overall efficiency of the postoperative long-term observation group was 78.3%, compared with 90.0% in the short-term control group, and the inefficiencies increased from 10.0% to 21.7%. ②In the observation group, the mean of the AHI increased gradually with the follow-up time, and the blood oxygen gradually decreased. The effectiveness of the surgical treatment gradually decreased, the total efficiency of the tongue base traction group decreased from 100% to 60%, and the hyoid suspension group decreased from 94.4% to 77.8%. ③And 15 patients with a second review X-head shadow measurements,we found there are statistically significant (P<0.05) in vallecula epiglottica-lateral pharyngealwall,pharyngeal airway space. Conclusion:Repose screw system of tongue base traction/ hyoid suspension technique is positive in the treatment of severe OSAHS lingual pharyngeal plane obstruction, but short-term surgical results are not stable.

Accuracy of two-dimensional pharyngeal airway space prediction for bimaxillary orthognathic surgery.

The aim of this retrospective study was to evaluate the accuracy of two-dimensional (2D) virtual surgical planning (VSP) of pharyngeal airway space (PAS) in patients submitted to bimaxillary orthognathic surgery. This study was conducted with lateral cephalograms acquired through cone-beam computed tomography records of 33 patients, divided into group 1-patients submitted to maxillary advancement and mandibular setback (n = 17) and group 2-patients submitted to maxillomandibular advancement (n = 16). Records were taken 1 to 2months prior to surgery, which was used to perform the 2D VSP (Tp), and 6 to 8months after surgery (T1). In Dolphin Imaging software, the anteroposterior size of the PAS was calculated at the level of four craniometric points: A, occlusal plane (Mx), B, and pogonion (Pog). Two previously calibrated examiners performed these measurements. Statistical analyses were conducted using Kendall and t tests at a 5% level of significance. There was a concordance between the two examiners at all points and times. In group 1, points A and B have statistically significant differences between the PAS measurements performed in Tp and T1, while in group 2, none of the PAS points showed statistically significant differences when comparing Tp to T1. 2D computer-based cephalometric prediction in Dolphin Imaging software offers a good orientation to professionals during the surgical procedure of bimaxillary surgeries since its use is considered clinically relevant in daily practice.

Effect of semi-rapid maxillary expansion in children with obstructive sleep apnea syndrome: 5-month follow-up study.

The purpose of this study was to investigate the effect of semi-rapid maxillary expansion (SRME) orthodontic treatment on biomarkers and respiratory parameters in children with obstructive sleep apnea syndrome (OSAS) and maxillary transverse deficiency. Thirty children with OSAS were included in this study. Fifteen children were enrolled as control, and 15 children were subjected to SRME orthodontic treatment method for 5months. Beside respiratory parameters, pharyngeal area, dental arch, and postero-anterior widths and the levels of OSAS biomarkers in serum and urine were measured. Pharyngeal airway space, dental arch, and postero-anterior widths were increased after SRME treatment. Sleep tests showed a decrease in the apnea-hypopnea index (AHI) after 5-month control/treatment duration. Serum kallikrein (KLK)1 levels decreased significantly in the treatment group. There was a significant increase in serum orosomucoid (ORM)2 levels and a decrease in urine perlecan levels in the control group after a 5-month follow-up. A significant negative correlation between serum ORM2, perlecan, gelsolin, and KLK1 levels and intercanin width, as well as between serum ORM2 and KLK1 levels and intermolar width, was observed. SRME treatment can be considered as a useful approach in children with OSAS. A further investigation of OSAS-related biomarkers and their relationship with sleep and orthodontic parameters is needed for providing easier and reliable modulatory strategies in the treatment of OSAS.

Effects of bimaxillary orthognathic surgery on pharyngeal airway and respiratory function at sleep in patients with class III skeletal relationship

PurposeThe aim of this study was to examine the effects of bimaxillary orthognathic surgery on pharyngeal airway space (PAS) and respiratory function during sleep. Materials and methodsThe subjects were 21 patients with class III skeletal relationship, and all of the patients underwent bimaxillary surgery (Le Fort I advancement and bilateral sagittal split ramus setback osteotomies simultaneously). Pharyngeal volumes of nasopharyngeal (V-NPA), retropalatal (V-RPA), retrolingual (V-RLA), oropharyngeal (V-ORO) and total pharyngeal airways (V-TOT); minimum axial areas of retropalatal (MA-RPA), retrolingual (MA-RLA) and oropharyngeal airways (MA-ORO); and position of the hyoid were studied in order to detect dimensional PAS changes using cone-beam computed tomography (CBCT) with Dolphin 11.8 software immediately before surgery (T1) and during a period of 6–12 months postoperatively (T2) in all of the patients. Apnea–hypopnea index (AHI), respiratory disturbance index (RDI) and apnea in supine position (SupAHI) parameters were measured with a Compumedics E series full polysomnography system. ResultsIn volumetric measurements, the V-ORO parameter decreased significantly (p < 0,05) while there was no statistically significant change in the rest of the volumetric parameters (p > 0,05). All of the minimum axial area parameters were decreased significantly (p < 0,01). Hyoid bone moved inferiorly (p < 0,05) and posteriorly (p < 0,05). None of the polysomnographic parameters changed significantly (p > 0,05). ConclusionBimaxillary orthognathic surgery significantly narrowed PAS dimensions but did not cause an increase in AHI, which is a critical determinant parameter for obstructive sleep apnea syndrome.