Oropharyngeal Airway Space Research Articles

Volumetric analysis of pharyngeal airway dimensions and hyoid bone position following orthognathic surgery in skeletal class III patients: a cross sectional cephalometric study

Background: Objective of the study was to determine linear and volumetric changes in pharyngeal airway dimensions in class III patients treated by different modalities of orthognathic surgery and to compare the results of different orthognathic surgical modalities, and determine the change at the position of the hyoid bone. Methods: Pre and post-treatment lateral cephalogram of 53 class III adult patients who were treated by different modalities of orthognathic surgery studied to assess the changes in pharyngeal airway dimensions and hyoid bone position after orthognathic surgery. 28 patients were treated with mandibular set back, and 25 patients were treated with Bijaw surgery. Lateral cephalogram records were taken before treatment (T1), after surgery (T2), the end of the fixed treatment (T3) and 1 year after debonding (T4). Results: Interception of both surgical modalities has significant impact on various skeletal and pharyngeal parameters i.e., BMeH (0.00), PNS (0.009), MPS (0.13), GOP (0.001), IPS (0.007), SAS (0.006), and MAS (0.00). OJ (overjet) and OB (overbite) was significant especially after time interval of one year. In Bijaw groups, PPST4 parameter was significantly increased (0.0000), SPST4 (0.000), GOP (0.000), EPS (0.000) and IPS parameter was significantly decreased (0.045). Significant difference was observed in T4 time interval in superior pharyngeal airway space, posterior airway space and middle airway space with (p<0.05). Conclusions: Pharyngeal airway is significantly altered following orthognathic surgery in class III patients and it depends on the type of surgical modality employed were Bijaw surgery has significant impact on oropharyngeal and hypopharyngeal airway space.

Three-dimensional evaluation of upper pharyngeal airway, hyoid bone, and craniocervical changes following stabilization splint therapy in adult patients with temporomandibular joint disorders and mandibular deviation: A retrospective study

ObjectiveThis study aimed primarily to analyze the three-dimensional (3D) changes in the pharyngeal airway (PA), and secondarily, the hyoid bone (HB) and the craniocervical (CC) following stabilization splint (SS) therapy in adult patients with temporomandibular joint disorders (TMD) and mandibular deviation (MD). MethodsThirty-five adult patients with TMD and MD, who were treated using SS with a mean age of 25.14 ± 6.11 years, were enrolled in this retrospective clinical study. Pre- and post-therapeutic cone-beam computed tomography (CBCT) scans were analyzed. PA dimension,nasopharyngeal, oropharyngeal, hypopharyngeal, sub-hypopharyngeal, and total pharyngeal airway spaces were measured in surface area, volume, minimum constricted area (MCA) and width, HB position, and CC posture were analyzed three-dimensionally using InVivo 6.0.3 and Dolphin 11.95 software. Wilcoxon rank-sum or Paired t-test was conducted, and P < 0.05 was considered significant. ResultsSS therapy was administered for a period of 9.49 ± 4.02 months. The oropharyngeal airway space showed a significant decrease in sagittal width. The hypopharyngeal surface area, volume, MCA, and sagittal width decreased significantly. In terms of HB, hyoid–mandibular plane (H-MP), retrognathia–third vertebra's most inferior–anterior (RGN-C3ia), and retrognathia–Sella (RGN-S) distances significantly decreased. The Nasion–Sella line and the line that passes through C2ip to the odontoid process posterior tangent (NSL-OPT) angle in CC posture also decreased significantly. ConclusionSS therapy in TMD patients with MD mainly results in narrowing of the hypopharyngeal region, no change in HB position and improvement in head posture. These results undoubtedly assist in diagnosis and treatment of clinical conditions.

Transoral Endoscopy-Assisted Tongue-Lip Adhesion With Modified Tongue Base Suspension in a Pierre-Robin Sequence: A Safe and Effective Technique.

Life-threatening airway obstruction is a major concern in patients with Pierre-Robin sequence. Tongue-lip adhesion (TLA) has been used to manage airway obstruction. The authors present the case of a female neonate with Pierre-Robin sequence who presented with airway obstruction and a cleft palate. She underwent a TLA procedure with modified tongue base suspension (TBS). Endoscopy was used to check and control the traction of the tongue base to enable unobstructed self-ventilation. Positive outcomes including improved O2 saturation and weight gain were noted. The effectiveness of TLA was enhanced by using TBS with real-time endoscopy to evaluate the oropharyngeal airway space required to alleviate airway obstruction. The use of endoscopy enabled us to check and determine how much the tongue base should be tracted by manipulating the tongue anteriorly and posteriorly. The authors report transoral endoscopy-assisted TLA and modified TBS.

The Efficacy of the Partial Glossectomy for Prevention of Airway Volume Reduction in Orthognathic Surgery of Class III Patients

The aim of this study was to evaluate the effects of a partial glossectomy on volumetric changes of pharyngeal airway space (PAS) in patients with mandibular setback surgery. Overall, 25 patients showing clinical features related to macroglossia treated with mandibular setback surgery were included in this retrospective study. Subjects were divided into two groups: the control group (G1, n = 13, with BSSRO) and the study group (G2, n = 12, with both BSSRO and partial glossectomy). The PAS volume of both groups was measured by the OnDemand 3D program on CBCT taken shortly before operation (T0), 3 months post-operative (T1), and 6 months post-operative (T2). A paired t-test and repeated analysis of variance (ANOVA) were used for statistical correlation. Total PAS and hypopharyngeal airway space were increased after operation in Group 2 compared to Group 1 (p < 0.05), while oropharyngeal airway space showed no significant statistical difference with the tendency of increasing. The combination of partial glossectomy and BSSRO surgical techniques had a significant effect on increasing the hypopharyngeal and total airway space in class III malocclusion patients (p < 0.05).

Intraoperative occipital to C2 angle and external acoustic meatus-to-axis angular measurements for optimizing alignment during posterior fossa decompression and occipitocervical fusion for complex Chiari malformation.

Excess flexion or extension during occipitocervical fusion (OCF) can lead to postoperative complications, such as dysphagia, respiratory problems, line of sight issues, and neck pain, but posterior fossa decompression (PFD) and OCF require different positions that require intraoperative manipulation. The objective of this study was to describe quantitative fluoroscopic morphometrics in Chiari malformation (CM) patients with symptoms of craniocervical instability (CCI) and demonstrate the intraoperative application of these measurements to achieve neutral craniocervical alignment while leveraging a single axis of motion with the Mayfield head clamp locking mechanism. A retrospective cohort study of patients with CM 1 and 1.5 and features of CCI who underwent PFD and OCF at a single-center institution from March 2015 to October 2020 was performed. Patient demographics, preoperative presentation, radiographic morphometrics, operative details, complications, and clinical outcomes were analyzed. A total of 39 patients met the inclusion criteria, of which 37 patients (94.9%) did not require additional revision surgery after PFD and OCF. In this nonrevision cohort, preoperative to postoperative occipital to C2 angle (O-C2a) (13.5° ± 10.4° vs. 17.5° ± 10.1°, P = 0.047) and narrowest oropharyngeal airway space (nPAS) (10.9 ± 3.4 mm vs. 13.1 ± 4.8 mm, P = 0.007) increased significantly. These measurements were decreased in the two patients who required revision surgery due to postoperative dysphagia (mean difference - 16.6°° in O C2a and 12.8°° in occipital and external acoustic meatus to axis angle). Based on these results, these fluoroscopic morphometrics are intraoperatively assessed, utilizing a locking Mayfield head clamp repositioning maneuver to optimize craniocervical alignment prior to rod placement from the occipital plate to cervical screws. Establishing a preoperative baseline of reliable fluoroscopic morphometrics can guide surgeons intraoperatively in appropriate patient realignment during combined PFD and OCF, and may prevent postoperative complications.

CONE BEAM COMPUTED TOMOGRAPHY (CBCT) ANALYSIS OF OROPHARYNGEAL AIRWAY IN ANGLES CLASS II DIVISION I MALOCCLUSION FOLLOWING FUNCTIONAL APPLIANCE THERAPY

Objectives: To evaluate and compare the alterations taking place in the oro-pharyngeal airway space with functional appliance between class I &amp; treated class II division 1 subjects. The st Methods: udy comprised of forty ve participants. Of these, thirty subjects were divided into two groups (Group 1 &amp; 2) who had Angles Class II Division I malocclusion. Subjects with Angles Class I malocclusion formed the control group (Group 3) with 15 subjects. Group 1 received standard twin block therapy and Group 2 received xed functional appliance. The control group received xed mechanotherapy. A full skull CBCT scan was taken pre and post treatment in the two study groups and the control group to check for changes that occurred in the oro-pharyngeal volume. The volume of the oro-pharyngeal airway space was analyzed by student's t test and Tukey's post hoc tests using SPSS Version 22.0. (For Windows) Group 2 and group 3 exhibited a Results: statistically signicant increase in the mean oropharyngeal space volume (p &lt; 0.01) during the post treatment period when compared to the pretreatment. volumes. Increased oro-pharyngeal space was seen in twin block therapy Conclusion: since it brings about both skeletal and dento-alveolar changes while xed functional appliance showed comparatively less changes in the oropharyngeal space.

Cephalometric characteristics of the upper respiratory tract in Ukrainian young men and young women with an orthognathic bite without and with the type of face taken into account

The upper respiratory tract is a component of the respiratory system, which ensures the performance of several key human functions at once. The variability of cephalometric indicators of this structure of the human body, depending on the peculiarities of body structure, nationality, sex, and other factors, is one of the current topics of discussion among modern scientists. The purpose of the study is to establish the peculiarities of the cephalometric characteristics of the upper respiratory tract in young people without pathology of the upper respiratory tract with an orthognathic bite without and taking into account the type of face. For 72 Ukrainian young women and 46 young men with an orthognathic bite and the absence of pathology of the upper respiratory tract, taken from the database of the research center and the pediatric dentistry department of National Pirogov Memorial Medical University, Vinnytsya, determination of cephalometric parameters of the upper respiratory tract itself was carried out. The face type of young women and young men was determined using Garson's morphological index. The statistical analysis of the obtained results was carried out in the licensed statistical package “Statistica 6.0” using non-parametric estimation methods. In Ukrainian young women and young men without and taking into account the type of face, the percentile range of cephalometric parameters of the upper respiratory tract proper was established (distance PASmin – the size of the retroglossal oropharyngeal airway space, distance PM-UPW – the size of the nasopharyngeal airway space, distance U-MPW – the size of the retropalatal oropharyngeal airway space, distance V-LPW – the size of the hypopharyngeal airway space, area UAA – the size of the upper airway area). Sex differences (significantly greater, or a tendency towards greater values in young men) of distance V-LPW values were found in representatives without taking into account the face type by 13.8 %, with a wide face type – by 11.6 % and with a narrow face type – by 15.9 %; as well as the size of the UAA area in representatives without taking into account the face type by 20.6%, with a very wide face type – by 21.2 %, with a wide face type – by 21.6 % and with an average face type – by 23.1 %. Both in young women and in young men, no reliable differences or trends in the magnitude of the cephalometric parameters of the upper respiratory tract between representatives with different types of faces were established.

Research on effectiveness of occipito-odontoid angle in predicting dysphagia after occipitocervical fusion in patients with C 2, 3 Klippel-Feil syndrome

To introduce a new occipitocervical angle parameter, occipito-odontoid angle (O-Da), for predicting dysphagia after occipitocervical fusion (OCF) in patients with C 2, 3 Klippel-Feil syndrome (KFS) and analyze its effectiveness. A total of 119 patients met selective criteria between April 2010 and November 2019 were retrospectively included as the study subjects. There were 56 males and 63 females. The age ranged from 14 to 76 years, with a median age of 51 years. There were 44 cases of basilar invagination and 75 cases of atlantoaxial subluxation. Forty patients were combined with C 2, 3 KFS. Seven patients underwent anterior decompression combined with posterior OCF and 112 patients underwent posterior OCF. The fixed segments were O-C 2 in 36 cases, O-C 3 in 51 cases, O-C 4 in 25 cases, and O-C 5 in 7 cases. All patients were followed up 21-136 months, with a median time of 79 months. The lateral cervical X-ray films before operation and at last follow-up were used to measure the occipital to C 2 angle (O-C 2a), the occipital and external acoustic meatus to axis angle (O-EAa), the occipital protuberance to axial angle (Oc-Axa), the O-Da, and the narrowest oropharyngeal airway space (nPAS). The differences of the above parameters between the last follow-up and the preoperative values were calculated (represented as dO-C 2a, dO-EAa, dOc-Axa, dO-Da, and dnPAS). Patients were divided into two groups according to whether they suffered dysphagia after operation, and the differences in clinical data and radiographic parameters were compared between the two groups. The correlation between occipitocervical angle parameters and nPAS in 40 patients with C 2, 3 KFS was analyzed respectively. In addition, sensitivity and specificity analyses were used to assess the effectiveness of dO-Da≤-5° for the prediction of postoperative dysphagia. Thirty-one patients (26.1%) suffered dysphagia after OCF (dysphagia group), including 10 patients with C 2, 3 KFS; no dysphagia occurred in 88 patients (non-dysphagia group). There was no significant difference in age, follow-up time, fixed segment, proportion of patients with rheumatoid arthritis, proportion of patients with atlantoaxial subluxation, and proportion of patients with C 2, 3 KFS between the two groups ( P>0.05). The proportion of female patients was significantly higher in dysphagia group than in non-dysphagia group ( χ 2=7.600, P=0.006). The difference in preoperative O-C 2a between the two groups was significant ( t=2.528, P=0.014). No significant differences were observed in preoperative O-EAa, Oc-Axa, O-Da, and nPAS ( P>0.05). There was no significant difference in dO-C 2a, dO-EAa, dOc-Axa, dO-Da, and dnPAS between the two groups ( P>0.05). The dO-C 2a, dO-EAa, dOc-Axa, and dO-Da were positively correlated with dnPAS in 40 patients with C 2, 3 KFS ( r=0.604, P<0.001; r=0.649, P<0.001; r=0.615, P<0.001; r=0.672, P<0.001). Taking dO-Da≤-5° as the standard, the sensitivity and specificity of dO-Da to predict postoperative dysphagia in patients with C 2, 3 KFS were 80.0% (8/10) and 93.3% (28/30), respectively. The dO-Da is a reliable indicator for predicting dysphagia after OCF in patients with C 2, 3 KFS.

Relationship between craniofacial and dental arch morphology with pharyngeal airway space in adolescents.

The aim of the study was to investigate apossible relationship between pharyngeal airway space, craniofacial variables, and dental arch form in adolescents grouped by sex. This cross-sectional study included 108 adolescents aged between12 and 17years. Lateral cephalometric radiographs were used to analyze sagittal craniofacial variables and the pharyngeal airway space. For evaluation of the dental arch form, we used plaster models. Statistical analysis included Student's t‑test and Pearson's correlation coefficient(r). Maxillary length was directly proportional to upper nasopharyngeal airway dimensions in males (r = 0.312, p = 0.021) and females (r = 0.310, p = 0.022). In the female group, upper oropharyngeal measurements showed an inverse correlation with alabial inclination of the upper incisors (r = -0.415, p = 0.001), protrusion of the upper incisors (r = -0.364, p = 0.006), and soft palate thickness (r = -0.27, p = 0.043). In the male group, upper nasopharynx measurements showed an inverse correlation with soft palate thickness (r = -0.277, p = 0.042). The upper arch form appeared to be related to oropharyngeal measurements in females, while the lower arch form was related to oropharyngeal dimensions in males. The findings suggest that there are sex-dependent correlations of the nasopharyngeal and oropharyngeal airway space with the sagittal craniofacial morphology and the transversal dental arch form.

The predictive ability of occipital to C3 angle for dysphagia after occipitocervical fusion in patients with combined C2\u20133 Klippel-Feil syndrome

BackgroundImproper occipitocervical alignment after occipitocervical fusion (OCF) may lead to devastating complications, such as dysphagia and/or dyspnea. The occipital to C2 angle (O-C2a), occipital and external acoustic meatus to axis angle (O-EAa) have been used to evaluate occipitospinal alignment. However, it may be difficult to identify the inferior endplate of the C2 vertebra in patients with C2–3 Klippel-Feil syndrome (KFS). The purpose of this study aimed to compare four different parameters for predicting dysphagia after OCF in patients with C2–3 KFS.MethodsThere were 40 patients with C2–3 KFS undergoing OCF between 2010 and 2019. Radiographs of these patients were collected to measure the occipital to C3 angle (O-C3a), O-C2a, occipito-odontoid angle (O-Da), occipital to axial angle (Oc-Axa), and narrowest oropharyngeal airway space (nPAS). The presence of dysphagia was defined as the patient complaining of difficulty or excess endeavor to swallow. Patients were divided into two groups according to whether they had postoperative dysphagia. We evaluated the relationship between each of the angle parameters and nPAS and analyzed their influence to the postoperative dysphagia.ResultsThe incidence of dysphagia after OCF was 25% in patients with C2–3 KFS. The Oc-Axa, and nPAS were smaller in the dysphagia group compared to non-dysphagia group at the final follow-up (p < 0.05). Receiver-operating characteristic (ROC) curves showed that dO-C3a had the highest accuracy as a predictor of the dysphagia with an area under the curve (AUC) of 0.868. The differences in O-C3a, O-C2a, O-Da, and Oc-Axa were all linearly correlated with nPAS scores preoperatively and at the final follow-up within C2–3 KFS patients, while there was a higher R2 value between the dO-C3a and dnPAS. Multiple linear regression analysis showed that the difference of O-C3a was the only significant predictor for dnPAS (β = 0.670, p < 0.001).ConclusionsThe change of O-C3a (dO-C3a) is the most reliable indicator for evaluating occipitocervical alignment and predicting postoperative dysphagia in C2–3 KFS patients. Moreover, dO-C3a should be more than − 2° during OCF to reduce the occurrence of postoperative dysphagia.

Evaluation of pharyngeal airway width in relation to vertical facial types in children

The purpose of this retrospective study was to evaluate the pharyngeal airway width according to the vertical facial type in Korean children in the developmental stage. In total, 101 participants aged 7 - 11 years were selected and divided into three groups based on the mandibular plane angle. The size of pharyngeal airway width was assessed using lateral cephalograms. The data were statistically analyzed using one way ANOVA test and independent t-test.The vertical growth group showed significantly narrower nasopharyngeal and upper oropharyngeal airway width than that in the normal and horizontal growth groups. Lower nasopharyngeal airway width was the widest in the horizontal growth group and the difference was statistically significant. The vertical oropharyngeal airway space was significantly smaller in girls when compared to boys, and no distinct difference was observed between horizontal airway width of the sexes. The results from this study indicate that patients with vertical facial growth pattern had less pharyngeal airway width than the patients with normal and horizontal facial growth patterns.

An Observational Study to Evaluate Association Between Velopharyngeal Anatomy and Speech Outcomes in Adult Patients With Severe Velopharyngeal Insufficiency.

By measuring velopharyngeal structure and evaluating speech intelligibility, to explore and observe the association between velopharyngeal anatomy and speech outcomes in these patients. Thirty-one adult patients with velopharyngeal insufficiency after the primary palatoplasty aged 18 to 35 years (mean 22.03 years) were enrolled as the study group. The patients had significant hypernasality and audible nasal emission. The degree of velopharyngeal closure assessed by electronic nasopharyngeal fiberoptic endoscopy was grade III. Cephalometric analysis was performed on lateral cephalograms to measure velopharyngeal structure, including hard palate length (ANS-PNS), velar length (PNS-U), pharyngeal depth (PNS-PPW), and oropharyngeal airway space (U-MPW). Their speech intelligibility was evaluated through the Mandarin Chinese speech intelligibility test, and each speech sample was examined by 2 speech and language pathologists. The results were assessed with the SPSS 23.0 software package, and regression analysis was used to examine the relationship between velopharyngeal structure and speech outcomes. A significant negative correlation was confirmed between speech intelligibility and pharyngeal depth. Pharyngeal depth also showed a linear relationship with speech intelligibility, and there was no significant correlation between speech intelligibility and other measures (hard palate length, velar length, oropharyngeal airway space). In the velopharyngeal anatomy, only pharyngeal depth was associated with speech intelligibility in adult patients with severe velopharyngeal insufficiency, this is consistent with our clinical observation. It suggests that appropriate reduction of pharyngeal depth during palatopharyngoplasty may have a good effect on the speech recovery in patients with cleft palate and patients with velopharyngeal insufficiency after palatorrhaphy.

Pharyngeal airway space changes and stability following an extended LeFort-I osteotomy advancement in cleft lip and palate and non-cleft lip and palate patients: A long term comparison study

PurposeThe aim of this study was to evaluate effects of extended maxillary advancement osteotomy on pharyngeal airway space (PAS) in mid-facial deficient cleft lip and palate (CLP) patients and mid-facial deficient non-CLP patients. MethodsPharyngeal airway space (PAS) of 10 CLP and 10 non-CLP patients with the mean age of 19 years 10 months was measured on digitized lateral cephalograms taken shortly before maxillary advancement operation with Quadrangular Le Fort I osteotomy (QLF-I) (T0), early post-operative, (T1) and long term post-operative (T2). Two way repeated analysis of variance, independent samples t-test and correlations tests were used for statistical analysis of airway and skeletal changes. ResultsTotal PAS depth and area was significantly increased after the advancement and was stable in long term post-operative period for CLP and non-CLP patients. Nasopharyngeal and velopharyngeal airway space depth and area was statistically increased at T1 and T2 for both groups. Oropharyngeal airway depth and area showed no significant statistical difference at any of the time points. The effect of QLF-I osteotomy on (PAS) was similar in both CLP and non-CLP patients. ConclusionsNasopharyngeal, velopharyngeal, and total pharyngeal airway space depth and area increased after maxillary advancement with the QLF-I osteotomy; this increase was stable in long term follow up. Maxillary advancement with the QLF-I technique had no significant effect on oropharyngeal airway space depth and area in both CLP and non-cleft patients.

Evaluation of Central Obesity, Increased Body Mass Index, and its Relation to Oropharyngeal Airway Space Using Lateral Cephalogram in Risk Prediction of Obstructive Sleep Apnea.

Introduction:Maxillofacial radiologists play a significant role in detecting airway changes using radiographic tools. Clinical examination parameters and lateral cephalogram parameters play a vital role in diagnosing obstructive sleep apnea (OSA) and dreadful consequences.Aim and Objectives:This study aims to evaluate central obesity, increased body mass index (BMI), and its relation to oropharyngeal airway space using lateral cephalogram in risk prediction of OSA. Objectives are to measure central obesity and BMI.Methodology:BMI is measured using World Health Organization guidelines to measure oropharyngeal airway space and the tongue and soft palate area using lateral cephalogram to predict OSA's risk using Berlin's questionnaire. Age group between 18 and 60 years with 20 individuals in each group will be present in the study.Conclusion:Cephalometric upper airway space and soft-tissue variables in different BMI groups were compared, and it was found that there was a decrease in SPAS, MAS with an increase in BMI, and in patients with BMI <24, there was narrower nasopharynx and oropharynx.

Predictive abilities of O-C2 angle, O-EA angle, and Oc-Ax angle for the development of dysphagia in patients after occipitocervical fusion

To compare the predictive abilities of O-C2 angle (O-C2a), O-EA angle (O-EAa), and Oc-Ax angle (Oc-Axa) for development of dysphagia in patients after occipitocervical fusion (OCF). Between April 2010 and May 2019, 114 patients who underwent OCF and met the selection criteria were selected as the research objects. Among them, 54 were males and 60 were females; they were 14-76 years old, with an average of 50.6 years old. The follow-up time was 13-122 months (median, 60.5 months). The O-C2a, O-EAa, Oc-Axa, and the narrowest oropharyngeal airway space (nPAS) were measured by the lateral X-ray films before operation and at last follow-up, and the differences before and after operation (dO-C2a, dO-EAa, dOc-Axa, and dnPAS) were calculated. Patients were divided into two groups according to whether they had developed postoperative dysphagia. The general data including age, gender, fixed segment, proportion of patients with rheumatoid arthritis (RA), atlantoaxial subluxation (AS), and combined with anterior release surgery (ARS), and imaging indicators were compared between the two groups. The correlations between dO-C2a, dO-EAa, and dOc-Axa and dnPAS in 114 patients were analyzed to further compare the predictive value of three imaging indicators for occurrence of dysphagia after OCF. Dysphagia occurred after OCF in 31 cases with the incidence of 27.2%. There was significant difference in gender between the dysphagia group and the non-dysphagia group ( χ 2=7.940, P=0.005). There was no significant difference between the two groups in age, fixed segment, the proportion of patients with RA, the proportion of patients with AS, and the proportion of patients combined with ARS ( P>0.05). There was no significant difference in O-C2a and Oc-Axa of 114 patients before operation and at last follow-up ( P>0.05). The differences in O-EAa and nPAS were significant ( P<0.05). There was no significant difference in preoperative O-EAa, Oc-Axa, and nPAS between the dysphagia group and the non-dysphagia group ( P>0.05); the difference in the O-C2a was significant ( t=2.470, P=0.016). At last follow-up, the differences in the above imaging indicators were significant ( P<0.05). There were significant differences in the dO-C2a, dO-EAa, dOc-Axa, and dnPAS between the two groups ( P<0.05). Correlation analysis showed that the dO-C2a, dO-EAa, dOc-Axa were all positively correlated with dnPAS ( P<0.05). The dO-C2a≤-5°, postoperative O-EAa≤100°, postoperative Oc-Axa≤65° were all related to postoperative dysphagia ( P<0.05), and the highest risk factor suffering postoperative dysphagia was dO-C2a ≤-5° with a significant OR of 14.4. The dO-C2a, postoperative O-EAa, and postoperative Oc-Axa can be used as the predictive indexes of dysphagia after OCF, among which dO-C2a has the highest predictive value.

Predictive ability of pharyngeal inlet angle for the occurrence of postoperative dysphagia after occipitocervical fusion

BackgroundPIA has been proven to be a predictor for postoperative dysphagia in patients who undergo occipitospinal fusion. However, its predictive effect for postoperative dysphagia in patients who undergo OCF is unknown. The aim of this study was to evaluate the predictive ability of the pharyngeal inlet angle (PIA) for the occurrence of postoperative dysphagia in patients who undergo occipitocervical fusion (OCF).MethodsBetween 2010 and 2018, 98 patients who had undergone OCF were enrolled and reviewed. Patients were divided into two groups according to the presence of postoperative dysphagia. Radiographic parameters, including the atlas-dens interval (ADI), O-C2 angle (O-C2a), occipital and external acoustic meatus to axis angle (O-EAa), C2 tilting angle (C2Ta), C2-7 angle (C2-7a), PIA and narrowest oropharyngeal airway space (nPAS), were measured and compared. Simple linear regression and multiple regression analysis were used to evaluate the radiographic predictors for dysphagia. In addition, we used PIA = 90° as a threshold to analyze its effect on predicting dysphagia.ResultsOf the 98 patients, 26 exhibited postoperative dysphagia. Preoperatively, PIA in the dysphagia group was significantly higher than that in the nondysphagia group. We detected that O-C2a, O-EAa, PIA and nPAS all decreased sharply in the dysphagia group but increased slightly in the nondysphagia group. The changes were all significant. Through regression analyses, we found that PIA had a similar predictive effect as O-EAa for postoperative dysphagia and changes in nPAS. Additionally, patients with an increasing PIA exhibited no dysphagia, and the sensitivity of PIA <90° in predicting dysphagia reached 88.5%.ConclusionsPIA could be used as a predictor for postoperative dysphagia in patients undergoing OCF. Adjusting a PIA level higher than the preoperative PIA level could avoid dysphagia. For those who inevitably had decreasing PIA, preserving intraoperative PIA over 90° would help avert postoperative dysphagia.Trial registrationThis trial has been registered in the Medical Ethics Committee of West China Hospital, Sichuan University. The registration number is 762 and the date of registration is Sep. 9 th, 2019.

Follow-up observation of patients with obstructive sleep apnea treated by maxillomandibular advancement

This study aimed to evaluate the follow-up observation of patients with obstructivesleep apnea treated with maxillomandibular advancement (MMA) procedure with or without genial tubercle advancement (GTA). A total of 25 patients (mean age 37.1±17.3years) were included in the study. Cone-beam computed tomography scans were taken before treatment; after presurgical orthodontic treatment; immediately after MMA procedure; and follow-up visit. All Digital Imaging and Communications in Medicine files were analyzed using the Dolphin 3D Imaging software program (Dolphin Imaging and Management Solutions, Chatsworth, Calif) to determine the total airway volume (TAV), airway area (AA), and minimal cross-sectional area (MCA). Dolphin 3D voxel-based superimposition was used to determine the amount of skeletal advancement with MMA and changes after surgery. Significant increase in TAV, AA, and MCA was found with MMA treatment (40.6%, 28.8%, and 56.4%, respectively, P<0.0001). Smaller but significant decrease in TAV, AA, and MCA was found during a follow-up visit (20.0%, 9.7%, and 26.8%, respectively, P<0.0001) giving a net increase of TAV, AA and MCA (35.8%, 27.1%, and 45.9%, respectively). No significant differences were found in any of the airway measurements with or without the GTA procedure. The average forward movements of the maxilla, mandible, and chin were 6.6mm, 8.2mm, and 11.4mm, respectively. A relapse of less than 1mm was found in each of the variables during the follow-up period. No correlation was found between the magnitudes of skeletal advancement and the change in oropharyngeal airway space (OPAS). Significant increase in OPAS can be expected with MMA surgery with or without GTA procedure in patients diagnosed with obstructive sleep apnea. A partial loss in OPAS was found during the follow-up visit. The surgical movements were found to be stable, with less than 1mm of relapse during the follow-up period, which was not clinically significant.

Changes in the hyoid bone, tongue, and oropharyngeal airway space after mandibular setback surgery evaluated by cone-beam computed tomography

BackgroundMandibular setback surgery can change the position of the mandible which improves occlusion and facial profile. Surgical movement of the mandible affects the base of the tongue, hyoid bone, and associated tissues, resulting in changes in the pharyngeal airway space. The aim of this study was to analyze the 3-dimensional (3D) changes in the hyoid bone and tongue positions and oropharyngeal airway space after mandibular setback surgery.MethodsA total of 30 pairs of cone-beam computed tomography (CBCT) images taken before and 1 month after surgery were analyzed by measuring changes in the hyoid bone and tongue positions and oropharyngeal airway space. The CBCT images were reoriented using InVivo 5.3 software (Anatomage, San Jose, USA) and landmarks were assigned to establish coordinates in a three-dimensional plane. The mean age of the patients was 21.7 years and the mean amount of mandibular setback was 5.94 mm measured from the B-point.ResultsThe hyoid bone showed significant posterior and inferior displacement (P < 0.001, P < 0.001, respectively). Significant superior and posterior movements of the tongue were observed (P < 0.05, P < 0.05, respectively). Regarding the velopharyngeal and glossopharyngeal spaces, there were significant reductions in the volume and minimal cross-sectional area (P < 0.001). The anteroposterior and transverse widths of the minimal cross-sectional area were decreased (P < 0.001, P < 0.001, respectively). In addition, the amount of mandibular setback positively correlated with the amount of posterior and inferior movement of the hyoid bone (P < 0.05, P < 0.05, respectively).ConclusionThere were significant changes in the hyoid bone, tongue, and airway space after mandibular setback surgery.

Evaluation of the Oropharyngeal Airway Space in Class II Malocclusion Treated with Mandibular Activator: A Retrospective Study

The development of a class II malocclusion is usually related to a reduced oropharyngeal airway space. In order to prevent airway obstruction, functional appliances are commonly used for orthodontic therapy. The aim of the article is to verify if these appliances could positively influence oropharyngeal diameters preventing the onset of future respiratory disorders. A group of 10 patients treated at the Dental Clinic of San Gerardo Hospital in Monza with mandibular activator was selected. Ten similar untreated class II subjects with retrognathic mandible were used as control group. The cephalometric tracings were made on lateral teleradiographs of the skull before and after the active therapy with functional devices for the treated group and before and after growth peak for the control one. Descriptive statistical analysis was calculated for all the cephalometric values in both study cases and control group using Excel worksheet. The data distribution was evaluated with Shapiro-Wilk test and the in-between group discrepancies were evaluated with Mann-Whitney U test. At T1 period, both case and control groups showed a class II pattern. At T2 period, the study group shows an improvement in bones relationship with reduced ANB angles and OVJ measurements. The control group otherwise did not show any important changes in maxillo-mandibular discrepancies. The airway size increased in either group in most cases. No significant differences between the treated and control groups were detected for airway size neither in the upper, middle, nor lower level at the T1-T2 interval. The upper airway values did not show any significant discrepancies between the two groups during the observation period. Functional devices were effective in solving class II relationships, but there is no evidence of successful breathing disorders prevention by using mandibular activators, probably due to the stability of airway tissues reached in pubertal age in both groups.

Predictive abilities of O-C2a and O-EAa for the development of postoperative dysphagia in patients undergoing occipitocervical fusion

Background ContextDysphagia is a common postoperative complication in patients undergoing occipitocervical fusion (OCF). Previous studies had proposed the use of two measures—the occipital to C2 angle (O-C2a) and the occipital and external acoustic meatus to axis angle (O-EAa)—to predict postoperative dysphagia after OCF. However, these studies had small sample sizes and the predictive abilities of both measures are still not clear. PurposeTo evaluate the predictive ability of O-EAa and O-C2a for dysphagia after OCF. Study DesignA retrospective clinical study. Patient SampleA total of 109 consecutive patients who had undergone OCF. Outcome MeasuresPresence of postoperative dysphagia, O-C2a, C2 tilting angle (C2Ta), O-EAa, and the narrowest oropharyngeal airway space (nPAS). MethodsBetween April 2010 and June 2018, 109 consecutive patients who had undergone OCF were reviewed. Patients were divided into two groups according to the presence of postoperative dysphagia. Radiographic measurements, including O-C2a, C2Ta, O-EAa, and nPAS, were evaluated at preoperative and 1 month postoperative and the findings were compared. Simple linear regression was used to measure the correlations between the parameters and the presence of dysphagia, and the correlations within the parameters. Multiple regression analysis was used to examine the variables that affected the change of nPAS (dnPAS%). Sensitivity and specificity analyses were used to evaluate the effectiveness of the previously proposed measures (“O-C2a change≤−5°” and “postoperative O-EAa<100°”) for prediction of post-OCF dysphagia. ResultsThe incidence of dysphagia after OCF was 26.6% (29/109). Preoperative values for the radiographic parameters were similar between patients with and without dysphagia. In the dysphagia group, both O-C2a and O-EAa values showed a dramatic decrease after surgery, which was accompanied by a decrease in nPAS. Postoperative O-C2a, O-EAa, and nPAS in the dysphagia group were significantly smaller than those in the nondysphagia group (p<.05). The changes in O-EAa, O-C2a, and nPAS showed a linear correlation with the presence of dysphagia (p<.05). In addition, linear correlations were found between two of the three parameters. Multiple regression showed the change of O-C2a and O-EAa were significant predictors for dnPAS% (β=0.200, p=.022 and β=0.549, p=.000). The sensitivity and specificity of “O-C2a change≤−5°” in predicting dysphagia were 75.9% and 80.0% respectively, and those of “postoperative O-EAa<100°” were 75.9% and 62.5%, respectively. However, the sensitivity of the combination of these two values in predicting postoperative dysphagia was as high as 96.6%. ConclusionBoth O-EAa and O-C2a could be critical predictors for postoperative dysphagia. During surgery, ensuring that the O-EAa exceeds 100° and simultaneously avoiding an O-C2a reduction greater than 5° could effectively avert postoperative dysphagia.