scholarly journals Postoperative Skeletal Stability and Pharyngeal Airway: Counterclockwise versus Clockwise Rotation during Mandibular Setback Surgery

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Yu-Chuan Tseng ◽  
Szu-Yu Hsiao ◽  
Jung-Hsuan Cheng ◽  
Kun-Jung Hsu ◽  
Chun-Ming Chen
Keyword(s):  
Soft Palate ◽  
Clockwise Rotation ◽  
Time Intervals ◽  
Physiological Regulation ◽  
Pharyngeal Airway ◽  
Mandibular Setback ◽  
The Mean ◽  
Mandibular Setback Surgery ◽  
Craniovertebral Angle ◽  
Skeletal Stability

Purpose. To compare the effects of counterclockwise rotation (CCR) and clockwise rotation (CR) of the mandible on the pharyngeal airway during mandibular setback surgery. Materials and Methods. Serial cephalograms of 40 patients with mandibular prognathism, including 20 who underwent CCR and 20 who underwent CR, were taken at the following time intervals: preoperatively (T1), immediately postoperatively (T2), >1 year after surgery (T3), final surgical changes (T31), postoperative stability (T32), and immediate surgical change (T21). Changes in menton (Me) and hyoid (H) positions, soft palate width, soft palate length, soft palate angle and craniovertebral angle (C2C4-SN), and pharyngeal airway spaces (nasal pharyngeal airway (NOP), uvula pharyngeal airway (UOP), tongue pharyngeal airway (TOP), and epiglottis pharyngeal airway (EOP)) were evaluated. Results. The mean Me (T31) setback for CCR and CR was 12.56 and 13.06 mm, respectively, with 2.41 mm upward and 3.29 mm downward, respectively. The vertical Me position of CR exhibited significant downward movement compared with that of CCR. The mean H setback results for CCR and CR were 4.42 and 5.75 mm, respectively, with 1.47 mm downward and 2.97 mm downward, respectively. The C4C2-SN angles for CCR and CR increased by 2.68° and 3.65°, respectively, whereas their palatal angles increased by 2.35° and 5.25°, respectively. Pearson’s correlation analysis (T31) revealed that for CCR, no pharyngeal airway spaces were significantly correlated with any measured variables. In CR, NOP was significantly correlated (r = 0.58) with the vertical Me position. Significant relapse (T32) was observed after CR in the horizontal (r = −0.72) and vertical (r = −0.82) Me positions. Conclusion. Pharyngeal airway space narrowed postoperatively, and its patency was appropriately maintained through natural physiological regulation of the craniovertebral angle (C2C4-SN). Significant postoperative relapse was correlated with CR.

scholarly journals Changes in Pharyngeal Airway After Mandibular Setback Surgery: A Retrospective Cephalometric Study

2019 ◽  
Vol 53 (4) ◽  
pp. 256-263
Author(s):  
Jayshree D. Daryanani ◽  
N. Vijay ◽  
K. Sadashiva Shetty ◽  
Riddhi Chawla
Keyword(s):  
Soft Palate ◽  
Sagittal Split Ramus Osteotomy ◽  
Mandibular Prognathism ◽  
Pharyngeal Airway ◽  
Mandibular Setback ◽  
Mandibular Setback Surgery ◽  
Cephalometric Study ◽  
Base Of The Tongue

Aim: To cephalometrically evaluate the alterations taking place in the pharyngeal airway space, hyoid bone, soft palate, and head posture after mandibular setback surgery (bilateral sagittal split osteotomy) for correction of mandibular prognathism, as well as to evaluate the immediate postsurgical and more than 6 months postsurgical adaptations of these structures. Setting and Design: A retrospective cephalometric study. Materials and Method: The study group consisted of 40 nongrowing patients (20 females and 20 males) with mandibular prognathism and ANB less than or equal to –2 degree for which mandibular setback surgery by bilateral sagittal split ramus osteotomy was performed along with fixed appliance therapy. There presurgical (T1), immediate postsurgical (T2), and more than 6 months postsurgical (T3) lateral cephalograms were analyzed. Statistical Analysis Used: Intragroup comparison was done by paired t-test. Results: Skeletal measurements after orthognathic surgery remained stable in the long term. It was evident that mandibular setback surgery narrowed the pharyngeal airway; however, these changes were not significant except at the base of the tongue. During the follow-up airway measurements at the base of the tongue, the intersection of tongue at the inferior border of mandible and the vallecula increased but they did not reach the presurgical values. Soft palate length increased significantly after surgery. Angulation of soft palate to nasal line also increased significantly following surgery but decreased during follow-up. Extension of the head occurred after surgery which was maintained even at long term. Conclusion: Careful analysis of airway should be performed, particularly in connection with large anteroposterior discrepancies and in those who have risk factors for development of obstructive sleep apnea. Such cases should be corrected by combined maxillary and mandibular osteotomies.

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

2010 ◽  
Vol 80 (2) ◽  
pp. 302-308 ◽  
Author(s):  
Soonshin Hwang ◽  
Chooryung Judi Chung ◽  
Yoon-Jeong Choi ◽  
Jong-Ki Huh ◽  
Kyung-Ho Kim
Keyword(s):  
Pharyngeal Airway ◽  
Mandibular Setback ◽  
Intraoral Vertical Ramus Osteotomy ◽  
Mandibular Setback Surgery ◽  
Vertical Ramus Osteotomy

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

2016 ◽  
Vol 86 (6) ◽  
pp. 976-982 ◽  
Author(s):  
Darshit H. Shah ◽  
Ki Beom Kim ◽  
Mark W. McQuilling ◽  
Reza Movahed ◽  
Ankit H. Shah ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pressure Drop ◽  
Negative Correlation ◽  
Significant Negative Correlation ◽  
Class Iii ◽  
Time Points ◽  
Pharyngeal Airway ◽  
Mandibular Setback ◽  
Mandibular Setback Surgery

ABSTRACT 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.

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