Correlation Analysis between Three-Dimensional Changes in Pharyngeal Airway Space and Skeletal Changes in Patients with Skeletal Class II Malocclusion following Orthognathic Surgery

Introduction. Studies on the pharyngeal airway space (PAS) changes using three-dimensional computed tomography (CT) have shed more light on patients with Class III than Class II malocclusion. This paper focuses on analyzing the long-term changes in the PAS and evaluating the postoperative association between these PAS and skeletal changes in patients with skeletal Class II malocclusion who have undergone orthognathic surgery. Methods. The records of 21 patients with skeletal Class II malocclusion who had undergone orthognathic surgery were included. The anatomical modifications in both jaws, changes in volume, sectional area (SA), minimum sectional area (MSA), and anterior-posterior (AP) and transverse (TV) width in the airway at one month before surgery ( T 0 ), and one month ( T 1 ) and one year ( T 2 ) after surgery were analyzed using CT images. The association between the skeletal and airway changes was evaluated between T 0 , T 1 , and T 2 . Results. After surgery, the ANS, A point, and PNS demonstrated significant posterior and superior movement. The B point and the pogonion exhibited substantial anterior and superior movement. The total and inferior oropharyngeal volumes (vol 3, vol 4) notably increased, while the nasopharyngeal volume (vol 1) decreased. The anterior-posterior movement at the ANS and PNS after surgery was significantly associated with the total volume, vol 2, vol 3, SA 1, MSA, and TV width 1, while substantial association with the total volume was found at the pogonion. Conclusion. Thus, an ideal treatment plan can be formulated for patients with skeletal Class II malocclusion by considering the postoperative PAS changes.

Preventing the Catastrophe: Aberrant Carotid in Adenoid and Tonsil Surgery: Two Case Reports

Background: Adenoid and tonsil surgeries are the most commonly done surgical procedures, with haemorrhage being an important complication. Fatalities due to haemorrhage almost never occur, but the occasional devastating outcomes that are life-threatening become a frequent source of litigations and audits. Catastrophic bleeds are usually due to an aberrant vessel or carotid protruding in the pharyngeal airway. The aberrant carotid poses a risk during routine pharyngeal surgeries like adenoidectomy, tonsillectomy, Quincy and Para-pharyngeal abscess drainage, UPPP, pharyngeal biopsies, etc. and injuries during routine pharyngeal surgical procedures can be catastrophic due to massive bleeding. Case report: We report two cases of routine Adeno-tonsillectomy surgeries where aberrant carotid vessels protruding in the adeno-tonsil surgical area were identified by endoscopic transoral evaluation intraoperatively. The surgery in these cases was postponed for further investigation due to the risk of injury and catastrophic bleeding. Conclusion: Aberrant carotids are usually clinically silent, and adenoid removal in most cases is a blind procedure done by curettage. There are no guidelines to identify aberrant vessels pre or intraoperatively, and preventing injury and catastrophic bleeding depends on surgeon’s experience and caution. These cases underline the importance of due vigilance and taking steps before starting the procedures, particularly pre-and intraoperative transoral endoscopic assessment for identifying aberrant vessels in the upper airway area, thus preventing injury and avoiding devastating complications. We report these cases and underline the steps to identify aberrant vessels in the upper airway surgical field before starting surgery to prevent a potentially catastrophic complication.

AI-Based Automatic Segmentation of Craniomaxillofacial Anatomy From CBCT Scans for Automatic Detection of Pharyngeal Airway Evaluations in OSA patients

This study aims to generate and also validate an automatic detection algorithm for pharyngeal airway on CBCT data using an AI system which will procure an easy, errorless and fast method. The second aim is to validate the newly developed artificial intelligence system in comparison to commercially available software for 3D CBCT evaluation. A Convolutional Neural Network based machine learning algorithm did the segmentation of the pharyngeal airways in OSA and non-OSA patients. Radiologists used a semi-automatic software to manually determine the airway and their measurements were compared with the AI. OSA patients were classified as minimal, mild, moderate and severe groups and the mean airway volumes were compared. Narrowest points (mm), airway areas (mm2) and airway volumes (cc) of both OSA and non-OSA patients were also compared. There was no statistically significant difference between the manual and Diagnocat measurements in all groups (p>0.05). According to the results of the Diagnocat and manual segmentation, a successful algorithm which can automatically segment the pharyngeal airway from was created which can be used for a swift and precise measurement of pharyngeal airway volume.

Loeys-Dietz and Shprintzen-Goldberg syndromes: analysis of TGF-β-opathies with craniofacial manifestations using an innovative multimodality method

BackgroundElevated transforming growth factor-beta (TGF-β) signalling has been implicated in the pathogenesis of Loeys-Dietz syndrome (LDS) and Shprintzen-Goldberg syndrome (SGS). In this study, we provide a qualitative and quantitative analysis of the craniofacial and functional features among the LDS subtypes and SGS.MethodsWe explore the variability within and across a cohort of 44 patients through deep clinical phenotyping, three-dimensional (3D) facial photo surface analysis, cephalometric and geometric morphometric analyses of cone-beam CT scans.ResultsThe most common craniofacial features detected in this cohort include mandibular retrognathism (84%), flat midface projection (84%), abnormal eye shape (73%), low-set ears (73%), abnormal nose (66%) and lip shape (64%), hypertelorism (41%) and a relatively high prevalence of nystagmus/strabismus (43%), temporomandibular joint disorders (38%) and obstructive sleep apnoea (23%). 3D cephalometric analysis demonstrated an increased cranial base angle with shortened anterior cranial base and underdevelopment of the maxilla and mandible, with evidence of a reduced pharyngeal airway in 55% of those analysed. Geometric morphometric analysis confirmed that the greatest craniofacial shape variation was among patients with LDS type 2, with distinct clustering of patients with SGS.ConclusionsThis comprehensive phenotypic approach identifies developmental abnormalities that segregate to mutation variants along the TGF-β signalling pathway, with a particularly severe phenotype associated with TGFBR2 and SKI mutations. Multimodality assessment of craniofacial anomalies objectively reveals the impact of mutations of the TGF-β pathway with perturbations associated with the cranium and cranial base with severe downstream effects on the orbit, maxilla and mandible with the resultant clinical phenotypes.

Necessary diagnostic criteria of dental crowding in children during mixed dentition with different facial skeleton growth patterns

Annotation. Pathology of dental crowding during mixed dentition is one of the most common and difficult in the practice of dentist-orthodontist. Its prevalence, according to modern scientific data reaches 77% and occurs in all pathologies of occlusion (malocclusions). The aim of our study is to establish the relationship between the formation of dental crowding and the growth patterns of facial skeleton during mixed dentition in order to improve the effectiveness of orthodontic treatment. We used 42 pairs of plaster models and 42 slices of cone-beam computed tomography images (CBCT) for patients aged 7 to 11 years. Randomization of patients into study groups was performed according to the facial skeleton growth patterns and the Little index value. The analysis was performed by the method of variation statistics taking into account the mean values (mode, median, arithmetic mean) and mean error (M) with the assessment of reliable values by Student’s t-test, as well as determining the correlation coefficient using the Pearson pairwise method to detect connections between the obtained indicators at the minimum probability threshold p<0.05 using the statistical package EZR v. 1.35. According to the results of the examined patients: 30 people (71.4%) had a severe degree of dental crowding on both maxilla and mandible (LII> 8 mm.), more often it was associated with the neutral type of growth – 82% (with vertical – 60%). Statistically significant correlations were found between severe degree of dental crowding and vertical and neutral facial skeleton growth patterns (p<0.05). The results of the CBCT study showed that narrowing of the upper pharyngeal airway (UP) according to McNamara was more common in patients with neutral (85%) and vertical (80%) growth patterns with skeletal II and I class malocclusions according to Engle, which were 55% and 35%, respectively. The study revealed that the vast majority of children with dental crowding with different facial skeleton growth patterns had clinically significant disorders of the development of both maxillary and mandibular apical bases and airways which required immediate interceptive orthodontic treatment.

Review the Impact of Mandibular Setback Surgery for the Correction of Class III Malocclusion on the Upper Airway Space

AIM: This study aimed to review the scientific evidence related to the effect of mandibular setback surgery for the correction of Class III malocclusion on the changes in volume and anatomical structures’ positions of the upper airway within at least 1 year follow-up. METHODS: An electronic research was conducted on PubMed, Google scholar, and Elsevier up to April 20, 2021, the inclusion criteria were prospective or retrospective studies aiming to compare the changes in upper airway space following isolated mandibular setback through at least 1 year of follow-up. RESULTS: A total of 84 studies were retrieved, only 12 studies met the eligibility criteria. Their methods of measurement were using lateral cephalometry, CT, or Cone-beam computed tomography. Most of them showed narrowing in the Pharyngeal airway space, with some variability within the follow-up periods. Impact on the possibility of obstructive sleep apnea (OSA) was discussed in most of the included studies. CONCLUSION: Narrowing of upper airway volume is associated with isolated mandibular setback surgeries within 1 year of follow-up. However, OSA was not necessarily a consequence. Any predisposing factors for OSA should be considered before isolated mandibular setback surgery.

Three-dimensional assessment of airway volumes in patients with unilateral cleft lip and palate

Background Considering the adverse consequences of respiratory insufficiency in cleft lip and palate (CLP) patients, this study aimed to assess the pharyngeal airway dimensions in 9–12-year-old patients with unilateral CLP. This historical cohort evaluated the cone-beam computed tomography (CBCT) scans of 30 patients with non-syndromic unilateral CLP between 9 and 12 years and 30 age- and sex-matched non-cleft controls. Three-dimensional (3D) images were reconstructed by the Mimics software, and the nasopharyngeal, oropharyngeal, and total airway volumes, as well as the minimal cross-sectional area of the airway (minAx), and posterior airway length (PAL) were all measured in the sagittal plane. Data were analyzed by the Student’s t test. Results The oropharyngeal and the total airway volumes, as well as the minAx and PAL in CLP patients, were significantly smaller than the corresponding values in the control group (P < 0.05). Despite smaller nasopharyngeal airway volume in CLP patients than controls, this difference was not statistically significant (P > 0.05). Conclusions Nine- to twelve-year-old non-syndromic unilateral CLP patients have smaller pharyngeal airway dimensions than non-cleft controls, and are therefore at higher risk of respiratory insufficiency.

RELATION BETWEEN SAGITTAL POSITION OF THE MANDIBLE AND PHARYNGEAL AIRWAY VOLUME IN ADULTS USING CONE BEAM COMPUTED TOMOGRAPHY

Introduction: Many authors have discussed the relationship between craniofacial morphology and pharyngeal airway spaces in different malocclusions and skeletal patterns. So the aim of this work was to study the relation between sagittal position of the mandible and pharyngeal airway volume in adults using CBCT. Materials And Methods:Twentyone CBCT radiographs were collected from the archive of Radiology Department at Suez Canal University and were divided into 3 groups according to the measured SNB angle. Group 1 normal mandibular position, group 2 retrognathic mandible and group 3 prognathic mandible. Dolphin 3D imaging software was used to measure the airway volume for all the radiographs. Nasopharyngeal, oropharyngeal, hypopharyngeal and total pharyngeal airway volumes were measured for all the radiographs. F-test (ANOVA) was used for comparison between groups and Tukey test for pairwise comparisons. Correlations between variables were tested using PearsonÂ’s correlation coefficient. Results: there was statistically significant difference in the mean total pharyngeal airway volume and oropharyngeal airway volumes between the three groups. Nasopharyngeal airway volume and hypopharyngeal airway volume had non-significant difference between groups. There was a significant positive correlation between total pharyngeal airway volume (mm3) and SNB angle. Conclusion: Pharyngeal airway volume differs with different sagittal positions of the mandible. Pharyngeal airway volume decreases with mandibular retrognathism and increases with mandibular prognathism.

Changes in Tongue Area, Pharyngeal Area, and Pharyngeal Airway Velocity after Correction of Mandibular Prognathism

This study aimed to investigate the correlation between the amount of mandibular setback, and the related changes of the tongue area, pharyngeal area, and pharyngeal airflow velocity. Twenty-five patients treated for mandibular prognathism, and serial cephalograms were obtained (T1: preoperation, T2: more than one year postoperation). The postoperative area of the tongue, pharyngeal airway space, and pharyngeal airflow velocity were investigated. Statistical analysis was performed with the Student t-test and Pearson correlation. The amount of mandible setback was significant after surgery (12.8 mm; p < 0.001). The pharyngeal area was significantly reduced 115.5 mm2 (p = 0.046). There was a slight reduction of the tongue area (43.2 mm2; p = 0.305) and an increase of pharyngeal airflow velocity (0.3 m/s; p = 0.133). The Pearson correlation coefficient test showed no statistical significance among the amount of horizontal setback and vertical movement of the mandible, such as the reductions in the tongue area, the pharyngeal airway space, and the increase in pharyngeal airflow velocity. Larger amounts of mandibular setback caused a significant reduction of pharyngeal airway area, but without significant changes of the tongue area and pharyngeal airflow velocity.