Three-dimensional changes of the hyoid bone and airway volumes related to its relationship with horizontal anatomic planes after bimaxillary surgery in skeletal Class III patients

Objective:To evaluate longitudinal changes of the hyoid bone position and pharyngeal airway space after bimaxillary surgery in mandibular prognathism patients.Materials and Methods:Cone-beam computed tomography scans were taken for 25 mandibular prognathism patients before surgery (T0), 2 months after surgery (T1), and 6 months after surgery (T2). The positional displacement of the hyoid bone was assessed using the coordinates at T0, T1, and T2. Additionally, the volume of each subject''s pharyngeal airway was measured.Results:The mean amount of posterior maxilla impaction was 3.76 ± 1.33 mm as the palatal plane rotated 2.04° ± 2.28° in a clockwise direction as a result of bimaxillary surgery. The hyoid bone moved backward (P < .05, P < .001) and downward (P > .05, P < .05) at 2 months and 6 months after surgery, while the total volume of the pharyngeal airway significantly decreased at the same time points (P < .001, P < .001). There was significant relationship between the changes of the hyoid bone position and airway volume at 2 months after surgery (P < .05). The change of the palatal plane angle was positively correlated to the decrease in the total airway volume (P < .001).Conclusions:The null hypothesis was rejected. The hyoid bone moved inferoposteriorly, and the pharyngeal airway volume decreased for up to 6 months after bimaxillary surgery. The decrease in the pharyngeal airway volume was correlated to the changes in the palatal plane inclination and the positional change of the hyoid bone.     

Pharyngeal airway space,hyoid bone position and head posture after orthognathic surgery in Class III patients

Objective:To determine the effect of orthognathic surgery on pharyngeal airway in Class III patients and to (1) compare the results of different surgical techniques, (2) determine the change at the position of the hyoid bone, and (3) evaluate the craniocervical posture changes related to pharyngeal airway change.Materials and Methods:Forty-eight Class III adult patients were included in the study to assess airway space after orthognathic surgery. Nine patients were treated with maxillary advancement, seven patients were treated with mandibular set back, and 32 patients were treated with bimaxillary surgery. Cephalometric records were taken before treatment, after surgery, and about 1 year after surgery (at the end of the treatment).Results:No differences were determined at the position of hyoid bone and craniocervical posture. Nasopharyngeal area was significantly increased in all groups (P < .05). Oropharyngeal area and SPSS and IPS parameters were significantly decreased after mandibular set back operation (P < .05). In bimaxillary and maxillary advancement groups, PPS parameter was significantly increased (P < .01), and IPS parameter was significantly decreased (P < .05). No differences were detected at oropharyngeal and hypopharyngeal areas in bimaxillary and maxillary advancement groups.Conclusion:Different surgical procedures have different effects on pharyngeal airway space.     

The effect of mandibular setback or two-jaws surgery on pharyngeal airway among different genders

Cephalometric studies show significant gender differences in the size of the pharyngeal airway space. This study aimed to investigate and compare morphologic changes after mandibular setback or two-jaws surgery on the pharyngeal airway in men and women using computed tomography (CT). The sample included 34 women and 13 men diagnosed with Class III skeletal deformities, who had been treated by mandibular setback or bimaxillary surgery (maxillary advancement and mandibular setback). Anteroposterior, lateral and cross-sectional area dimensions of the airway, at the level of soft palate and base of tongue, were measured pre- and postoperatively on CT images. In the mandibular setback group, the anteroposterior and cross-sectional area of the pharyngeal airway at the level of the soft palate and base of tongue were significantly reduced for men or women (P < .05). In the two-jaws surgery group, only midsagittal anteroposterior dimensions at the same levels were significantly decreased for men or women (P < .05). The difference between any values measured between men and women who received bilateral sagittal split ramus osteotomy setback surgery or two-jaws surgery for the treatment of class III anteroposterior discrepancy were not statistically significant (P > .05). This study suggests that oropharyngeal airway measurements, important for airway patency, do not demonstrate sex dimorphism.     

Obwegeser II osteotomy (transoral angle osteotomy) for open bite with skeletal class III deformity

IntroductionThis study evaluated postoperative stability after Obwegeser II osteotomy (transoral angle osteotomy, first reported by Obwegeser 1973) for severe open bite with mandibular prognathism.Patients and methodsThis retrospective study reviewed 20 consecutive patients who underwent only mandibular Obwegeser II osteotomy to correct open bite and mandibular prognathism. Lateral cephalograms were evaluated preoperatively (T1), immediate postoperatively (T2) and at least 6 months after the surgery (T3). Surgical and postsurgical changes in cephalometric measurements were evaluated statistically.ResultsOpen bite with skeletal class III malocclusion was corrected by the Obwegeser II osteotomy alone. After an average of 9.9 ± 5.2 mm of mandibular setback with open bite closure (T2–T1, over-bite change, 5.7 ± 2.4 mm) by counter-clockwise rotation of the mandible, the patients showed 0.8 ± 1.7 mm of horizontal relapse (p > 0.05), 1.1 ± 1.7 mm of vertical relapse at the B point (p = 0.011) and −0.2 ± 1.6 mm of over-bite change postoperatively (T3–T2).DiscussionWith the adequate control of the condylar position with rigid internal fixation, Obwegeser II osteotomy showed acceptable stability after the correction of open bite with mandibular prognathism without a simultaneous maxillary osteotomy. An isolated Obwegeser II osteotomy can be considered a reliable option in cases with moderate to severe open bite with mandibular prognathism when the maxillary osteotomy is not needed if the patients have a well-positioned maxilla.     

Gender differences in morphological and functional outcomes after mandibular setback surgery

Purpose

The aim of this study was to examine and compare morphological and functional outcomes after either isolated mandibular setback or bimaxillary surgery in males and females.

Relapse of skeletal class III with anterior open bite after bimaxillary orthognathic surgery depending on maxillary posterior impaction and mandibular counterclockwise rotation

The goal of this study is to evaluate relapse after orthognathic surgery of skeletal class III with anterior open bite depending on the posterior impaction and mandibular counterclockwise rotation. Patients (n = 29) were divided into two groups according to the change of mandibular occlusal plane angle (MnOP): Group A had a clockwise change of MnOP > 0° (n = 11) and Group B had a counterclockwise change of MnOP < −2° (n = 18). Lateral cephalograms were analyzed preoperatively, and at immediate stage, six weeks, six months, and one year after surgery. One year after surgery, the stability of the maxilla was good in both groups. Upward movement of the mandible was observed six weeks after surgery due to mandibular autorotation. The amount of mean relapse was small, although a significant difference was observed horizontally between groups. Group B demonstrated more forward movement of B point, pogonion, and menton than Group A (p < 0.05). SNB angle increased in both groups (p < 0.05). At one year follow up, good occlusal stability was observed in both groups with positive overbite. Our study suggested that bimaxillary procedures with clockwise and counterclockwise rotation of mandibular occlusal planes for correction of mandibular prognathism with anterior open bite appeared to be relatively stable procedures.     

Pharyngeal airway space,hyoid bone position,and head posture after bimaxillary orthognathic surgery in Class III patients: Long-term evaluation

Objective:(1) To determine the effect of bimaxillary orthognathic surgery on pharyngeal airway, hyoid bone, and craniocervical posture in Class III bimaxillary surgery patients. (2) To evaluate short-term and long-term results. (3) To compare short- and long-term values.Materials and Methods:Twenty-six Class III adult patients treated with bimaxillary surgery were included in the study. Cephalometric records were taken before treatment (T1), before surgery (T2), and 5 months (T3), 1.4 years (T4), 3 years (T5), and 5 years (T6) postsurgery.Results:No significant differences were identified in craniocervical angulation between time intervals. There was a significant superior movement of hyoid bone at postsurgery (T3; P < .05); however, adaptation occurred to the normal position in the long term. A nonsignificant decrease occurred at the oropharyngeal middle pharyngeal distance parameter; however, this was compensated with a significant increase between T5 and T6 (P < .001). A significant decrease was observed in the hypopharyngeal Go-P parameter between T3 and T1 (P < .01), but it recovered with a nonsignificant increase in the long term. A significant increase in nasopharyngeal area was observed between T3 and T1 (P < .05). The hypopharyngeal area significantly increased between T5 and T6, and PNS-R significantly increased between T3 and T1 (P < .05).Conclusion:The pharyngeal areas adversely affected after surgery recover at long-term follow-up; thus, adaptation occurs after bimaxillary surgery.     

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.     

Morphological changes in the pharyngeal airway of female skeletal class III patients following bimaxillary surgery: A cone beam computed tomography evaluation

Using cone beam computed tomography (CBCT), the present study compared three-dimensional (3D) changes in the pharyngeal airway and surrounding tissues in female skeletal class III patients treated with bimaxillary surgery. Twenty-nine female skeletal class III patients with both maxillary hypoplasia and a mandibular excess underwent bilateral sagittal split ramus osteotomy for mandibular setback combined with Le Fort I osteotomy for maxillary advancement. Volumetric measurements were performed using CBCT scans taken at 1 week presurgery and 6 months post-surgery. The oropharynx volumes and the cross-sectional area behind the soft palate decreased significantly. There was an insignificant change in the volume of the nasopharynx (P > 0.05). The hyoid bone moved downward and posteriorly after surgery. The morphology of the soft palate also changed dramatically, with an increase in the length and thickness. Negative correlations were found between the pharyngeal airway space and the position of the hyoid bone. The change in morphology of the soft palate was significantly correlated with the changes in hyoid bone position. These 3D results suggest that bimaxillary orthognathic surgery significantly changes the position of the hyoid bone and the soft palate together with a significant decrease in the pharyngeal airway space in the correction of skeletal class III malocclusion.     

Airway changes and prevalence of obstructive sleep apnoea after bimaxillary orthognathic surgery with large mandibular setback

This study used three-dimensional computed tomography and polysomnography to evaluate the effect of a large mandibular setback on the postoperative pharyngeal airway space and obstructive sleep apnoea (OSA). Twelve patients who underwent bimaxillary surgery for a mandibular setback movement of >9 mm were included in this study. Changes in the pharyngeal airway space and polysomnography parameters based on the surgical movements were analyzed. The median mandibular setback movement was 11.08 mm. The total pharyngeal, oropharyngeal, and hypopharyngeal volumes, and the retroglossal cross-sectional area were significantly decreased postoperatively (P = 0.006; P = 0.005; P = 0.012; P = 0.005, respectively). The apnoea–hypopnoea index (AHI) increased significantly after surgery (P = 0.021). There were significant positive correlations between the preoperative inferiorly located hyoid bone and both AHI and respiratory disturbance index (RDI) postoperative (P = 0.008 and P = 0.027) and between the postoperative inferiorly dislocated retropalatal level and both AHI and RDI postoperative (P = 0.002 and P = 0.014). Four patients (33.3%) developed new onset OSA postoperatively. Large mandibular setback movements significantly reduced the pharyngeal airway space in the setting of bimaxillary surgery (P = 0.006).     

Dimensional changes of maxillary sinuses and pharyngeal airway in Class III patients undergoing bimaxillary orthognathic surgery

Objective:To evaluate the pharyngeal airway and maxillary sinus volume changes after mandibular setback surgery combined with maxillary advancement and/or impaction surgery.Materials and Methods:Seventeen Class III skeletal patients (11 females, 6 males) who required bimaxillary orthognathic surgery were selected. Volumetric measurements were performed using cone beam computed tomography (CBCT) scans preoperatively and 3.9 ± 0.87 months postoperatively. All the CBCT scans were assessed and analyzed using MIMICS 14.0 software. Preoperative and postoperative volumes of pharyngeal airway and maxillary sinuses and the relationship between the amounts of surgical movement of the jaws and the above volumes were statistically evaluated.Results:The pharyngeal airway area presented no significant change except for the lower and total pharyngeal airway volumes in males, in whom a significant decrease was observed (4196.27 ± 2061.11 mm³ and 3375.53 ± 3624.67 mm³, respectively). No significant change was observed in the minimal cross-sectional area of the pharyngeal airway. There was a significant decrease in the volume of the maxillary sinuses after the surgery by 3448.09 ± 3315.56 mm³. No correlation was found between the amount of skeletal movement and the change in the volume of pharyngeal airway or maxillary sinuses.Conclusion:There was a significant decrease only for lower and total pharyngeal airway volumes in males and a significant decrease in the volume of the maxillary sinuses.     

Changes of Hyoid,Tongue and Pharyngeal Airway after Mandibular Setback Surgery by Intraoral Vertical Ramus Osteotomy

Objective:To assess changes in hyoid, tongue, pharyngeal airway, and head posture in patients who had mandibular setback surgery by intraoral vertical ramus osteotomy (IVRO) and to investigate the influence of LeFort I osteotomy.Materials and Methods:Sixty patients with skeletal Class III malocclusion were evaluated. All patients had mandibular setback surgery via IVRO, and 45 patients had additional maxillary impaction surgery via LeFort I osteotomy. Lateral cephalograms were taken before, immediately after, approximately 1 month after, and at least 1 year after surgery. Parameters indicating the hyoid, tongue, pharyngeal airway, and head posture were evaluated.Results:The hyoid significantly moved inferoposteriorly immediately after surgery and relapsed superoanteriorly during observation periods. The tongue significantly moved posteriorly during all periods. The final position of the hyoid and tongue was significantly posterior, and the final pharyngeal airway was significantly narrower compared with its presurgical position. Significant cervical hyperflection occurred during observation periods and was strongly correlated with anterior movement of the hyoid. The hyoid and tongue showed similar positions regardless of the presence of different genders or LeFort I osteotomy after the long-term observation period.Conclusions:The hyoid and tongue moved posteriorly after mandibular setback surgery via IVRO, and there was a tendency to relapse back to its original position. However, the final pharyngeal airway width remained narrower after the long-term observation period. Based on our results, careful monitoring of the airway may be needed after mandibular setback surgery via IVRO.     

Three-dimensional evaluation of the pharyngeal airway using cone-beam computed tomography following bimaxillary orthognathic surgery in skeletal class III patients

Objective

The study aims to evaluate the pharyngeal airway space (PAS) following bimaxillary surgery in skeletal class III patients and to compare the changes in PAS between genders using cone-beam computed tomography (CBCT).

Materials and methods

In all, 38 patients (16 male and 22 female) with skeletal class III malocclusion underwent bimaxillary surgery. CBCT scans were acquired approximately 1 month before surgery, 3 months after surgery, and 6 months after surgery. The oropharyngeal volume and the minimum cross-sectional area (CSA) were characterized using the InVivoDental imaging software package at each time point.

Results

The volume and minimum CSA decreased significantly postoperatively, which was maintained until 6 months postoperatively (p < 0.01). The location of the minimum CSA tended to move into the retropalatal and retroglossal areas postoperatively. A strong correlation between volume and minimum CSA was found. The amount of mandibular setback was not correlated with the change in the airway. By gender, significant decreases in both the volume and minimum CSA were found in females (p < 0.05) but not in males.

Conclusion

Bimaxillary surgery significantly affects PAS. Gender differences should also be considered when considering changes in PAS.

Clinical relevance

An awareness of the effects of bimaxillary setback surgery on the airway should be considered when implementing an orthognathic treatment plan.

     

Bimaxillary ‘rotation advancement’ procedures in patients with obstructive sleep apnea: a 3-dimensional airway analysis of morphological changes

The aim of this retrospective three dimensional (3D) computed tomographic analysis was to investigate the morphological airway changes in 17 obstructive sleep apnea (OSA) patients following bimaxillary rotation advancement procedures. Morphological changes of the nasal cavity and naso-, oro- and hypopharynx were analysed separately, as were the total airway changes using nine parameters of airway size and four of shape. The Wilcoxon test was used to compare airway changes and the intraclass correlation coefficient to qualify inter-observer reliability. Following bimaxillary advancement and anti-clockwise maxillary rotation, the total airway volume and the lateral dimension of the cross-sectional airway increased significantly. The total length of the airway became shorter (p < 0.05). Remarkable changes were seen in the oropharynx: the length, volume, cross-sectional area (CSA), antero-posterior and medio-lateral distance changed (p < 0.05). This combined with a significant 3D change in the shape of the airway from round to elliptical. The average cross-sectional oropharyngeal area was nearly doubled, the minimal CSA increased 40%, and the hyoid bone was located more anterior and superior. Inter-examiner reliabilities were high (0.89). 3D airway analysis aids the understanding of postoperative pathophysiological changes in OSA patients. The airway became shorter, more voluminous, medio-laterally wider, and more compact and elliptical.     

Sagittal mandibular development effects on the dimensions of the awake pharyngeal airway passage

Objective:To test the hypothesis that sagittal mandibular development has no effects on the dimensions of the awake pharyngeal airway passage.Materials and Methods:Ninety-one subjects (age 15–25 years) with a normal vertical growth pattern of the mandible, normally positioned maxilla, and various sagittal mandibular developments were divided into three groups based on the sagittal mandibular development. Group I included 37 subjects who had a normally positioned mandible (76° ≤ angle between ‘S,’ ‘N,’ and ‘B’; it represents the antero-posterior position of the maxilla in relation to the anterior cranial base [SNB] ≤ 82°), Group II included 31 subjects in whom the mandible was retrognathic (SNB < 76°), and Group III included 23 subjects in whom the mandible was prognathic (SNB > 82°) in relation to the anterior cranial base. Lateral cephalograms were traced manually to evaluate the pharyngeal airway passage.Results:The length of the soft palate was significantly smaller in mandibular prognathism subjects than in subjects with mandibular retrognathism (P < .01). The thickness of the soft palate was significantly greater among subjects with mandibular prognathism than in subjects with normal (P < .01) and retrognathic (P < .001) mandibular development. The sagittal mandibular development had no effect on the dimensions of the nasopharyngeal and hypopharyngeal airway passage. The depth of the oropharynx was comparable among the subjects with normal and retrognathic mandibles but was greater (P < .001) among subjects with mandibular prognathism.Conclusions:The hypothesis is rejected. Sagittal mandibular development had significant effects on the dimensions of the awake pharyngeal airway passage.     

How does bimaxillary orthognathic surgery change dimensions of maxillary sinuses and pharyngeal airway space?

ObjectivesTo assess changes in the maxillary sinus (MS) and pharyngeal airway space (PAS) after bimaxillary orthognathic surgery using cone-beam computed tomography (CBCT).Materials and MethodsThe CBCT scans of 48 patients were divided into two groups: group 1: maxillary advancement and mandibular setback (n = 24); group 2: maxillomandibular advancement (n = 24). The CBCTs were acquired 1 to 2 months preoperatively and 6 to 8 months postoperatively. A kappa test was used to determine intra- and interexaminer agreement. Area, volume, and linear measurements of MSs and PASs obtained before and after surgery were compared using a mixed model (P < .05).ResultsAll variables of the MS showed significant postsurgical reductions in both groups, except the MS length, which showed a significant increase in group 2. Volume and minimum axial area of PAS showed statistically significant postsurgical increases in both groups (P < .05).ConclusionsDespite the reduction in the MS and the increase in the PAS, results indicated that the airway was not negatively affected after maxillomandibular advancement and maxillary advancement with mandibular setback.     

Cone-beam computed tomography evaluation of short- and long-term airway change and stability after orthognathic surgery in patients with Class III skeletal deformities: bimaxillary surgery and mandibular setback surgery

The purpose of this study was to evaluate the volumetric change of the upper airway space in 36 Class III patients who had undergone bimaxillary surgery or isolated mandibular setback, and, further, to analyse the relation between post-surgical stability and airway change using cone-beam computed tomography (CBCT). A three-dimensional (3D) CBCT examination was performed at three stages: T0 (before surgery), T1 (an average of 4.6 months after surgery), and T2 (an average of 1.4 years after surgery). The results showed that the volumes of the oropharyngeal and hypopharyngeal airways decreased significantly 4.6 months post-surgery in the mandibular setback group (p<0.05), and these diminished airways had not recovered 1.4 years post-surgery. In the bimaxillary surgery group, the volume of the oropharyngeal airway also decreased. A Spearman correlation analysis showed that the anteroposterior length of the hypopharyngeal area had a correlation with post-surgical stability in the isolated mandibular surgery group, and that the cross-sectional area of the nasopharynx was correlated with maxillary relapse only in the bimaxillary surgery group (p<0.05).     

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 1 year 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.     

Computational fluid dynamics for the assessment of upper airway changes in skeletal Class III patients treated with mandibular setback surgery

Objective:To analyze and compare pharyngeal airflow characteristics pre- and post–mandibular setback surgery in patients with Class III skeletal dysplasia using cone beam computed tomography (CBCT) and computational fluid dynamics (CFD).Materials and Methods:Records of 29 patients who had received orthodontic treatment along with mandibular setback surgery were obtained. CBCT scans were obtained at three time points: T1 (before surgery), T2 (average of 6 months after surgery), and T3 (average of 1 year after surgery). Digitized pharyngeal airway models were generated from these scans. CFD was used to simulate and characterize pharyngeal airflow.Results:Mean airway volume was significantly reduced from 35,490.324 mm³ at T1 to 24,387.369 mm³ at T2 and 25,069.459 mm³ at T3. Significant increase in mean negative pressure was noted from 3.110 Pa at T1 to 6.116 Pa at T2 and 6.295 Pa at T3. There was a statistically significant negative correlation between the change in airway volume and the change in pressure drop at both the T2 and T3 time points. There was a statistically significant negative correlation between the amount of mandibular setback and change in pressure drop at the T2 time point.Conclusions:Following mandibular setback surgery, pharyngeal airway volume was decreased and relative mean negative pressure was increased, implying an increased effort required from a patient for maintaining constant pharyngeal airflow. Thus, high-risk patients undergoing a large amount of mandibular setback surgery should be evaluated for obstructive sleep apnea and the proposed treatment plan be revised based on the risk for potential airway compromise.     

Effects of mandibular advancement surgery combined with minimal maxillary displacement on the volume and most restricted cross-sectional area of the pharyngeal airway

The purpose of this study was to evaluate changes in the volume and most restricted cross-sectional area of the pharyngeal airway as a result of mandibular advancement surgery with minimal maxillary displacement, and to ascertain the change in height of this restricted area and whether gender and age could influence these results. Cone beam computed tomography scans were obtained from 25 patients (seven male and 18 female, average age 35.5 years). The measurements were done using the InVivoDental software (version 5.0). Comparisons were made between measurements taken prior to treatment (T1) and postsurgery (T2, average 6.3 months after surgery). No variation was detected on the scans with regard to head position, which could influence the pharynx airway. Surgery significantly increased the pharynx airway volume at the total (P < 0.0001), upper (P = 0.0001), and lower (P < 0.0001) levels, with respective enlargements of 54.5%, 37.0%, and 91.3%. Gender and age did not influence this increase. A significant enlargement in the minimum area of the pharynx airway was detected (P < 0.0001), which changed in shape from a tapering to a rounded shape. Using binomial and multiple logistic regression tests, this constricted site presented an unpredictable change in position as a result of surgery, with no association to gender (P = 0.0745) or age (P = 0.5879).