Effects of bodily retraction of mandibular incisors versus mandibular setback surgery on pharyngeal airway space: A comparative study / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to compare the changes induced in the pharyngeal airway space by orthodontic treatment with bodily retraction of the mandibular incisors and mandibular setback surgery without extraction. METHODS: This retrospective study included 63 adult patients (32 men and 31 women). Thirty-three patients who had been treated via four-bicuspid extraction and bodily retraction of the mandibular incisors (incisor retraction, IR group) were compared with 30 patients who had been treated via mandibular setback surgery (MS group) without extraction. Lateral cephalograms were acquired and analyzed before (T1) and after treatment (T2). RESULTS: The superior pharyngeal airway space did not change significantly in either group during treatment. The middle pharyngeal airway space decreased by 1.15 ± 1.17 mm and 1.25 ± 1.35 mm after treatment in the IR and MS groups, respectively, and the decrease was comparable between the two groups. In the MS group, the inferior pharyngeal airway space (E-IPW) decreased by 0.88 ± 1.67 mm after treatment (p < 0.01). The E-IPW was larger in the MS group than in IR group at T1, but it did not differ significantly between the two groups at T2. No significant correlation was observed between changes in the pharyngeal airway space and the skeletal and dental variables in each group. CONCLUSIONS: The middle pharyngeal airway space decreased because of the posterior displacement of the mandibular incisors and/or the mandibular body. The E-IPW decreased only in the MS group because of the posterior displacement of only the mandibular body.

Retrospective study of changes in pharyngeal airway space and position of hyoid bone after mandibular setback surgery by cephalometric analysis / 대한악안면성형재건외과학회지

BACKGROUND: The posterior movement of mandible was known as the main cause of the changes in the pharyngeal airway space (PAS) and the postoperative obstructive sleep apnea (OSA). The purpose of this study was to know the changes of PAS and position of hyoid bone. METHODS: Lateral cephalographies of 13 patients who had undergone sagittal split ramus osteotomy (SSRO) setback surgery were taken preoperatively (T1), postoperatively within 2 months (T2), and follow-up after 6 months or more (T3). On the basis of F-H plane, diameters of nasopharynx, oropharynx, and hypopharynx were measured. The movements of the soft palate, tongue, and hyoid bone were also measured. RESULTS: The amount of mandible setback was 7.5 +/- 3.8 mm. In the measurements of PAS, there was a statistically significant decrease of 2.8 +/- 2.5 mm in nasopharynx (P < 0.01), and 1.7 +/- 2.4 mm in oropharynx (P < 0.01) were observed after surgery. The hypopharynx decreased 1.0 +/- 2.1 mm after surgery and continuously decreased 1.0 +/- 2.8 mm at follow-up. The changes in hyoid bone position showed the posterior movement only after surgery and posteroinferior movement at follow-up. CONCLUSIONS: The PAS such as nasopharynx, oropharynx, and hypopharynx showed relatively high correlation with the amount of mandibular setback. The change of resistance in upper airway may be important for the prevention of OSA after mandibular setback surgery.

Retrospective study on change in pharyngeal airway space and hyoid bone position after mandibular setback surgery

OBJECTIVES: The purpose of this study was to evaluate changes in the pharyngeal airway space and hyoid bone position after mandibular setback surgery with bilateral sagittal split ramus osteotomy (BSSRO) and to analyze the correlation between the amount of mandibular setback and the amount of change in pharyngeal airway space or hyoid bone position. MATERIALS AND METHODS: From January 2010 to February 2013, a total of 30 patients who were diagnosed with skeletal class III malocclusion and underwent the same surgery (BSSRO) and fixation method in the Division of Oral and Maxillofacial Surgery, Department of Dentistry at the Ajou University School of Medicine (Suwon, Korea) were included in this study. Lateral cephalograms of the 30 patients were assessed preoperatively (T1), immediately postoperatively (T2), and 6 months postoperatively (T3) to investigate the significance of changes by time and the correlation between the amount of mandibular setback and the amount of change in the airway space and hyoid bone position. RESULTS: Three regions of the nasopharynx, oropharynx, and hypopharynx were measured and only the oropharynx showed a statistically significant decrease (P<0.01). A significant posterior and inferior displacement of the hyoid bone was found 6 months after surgery (P<0.01). Analysis of the correlation between the amount of mandibular setback and the amount of final change in the airway space and hyoid bone position with Pearson's correlation showed no significant correlation. CONCLUSION: In this study, the oropharynx significantly decreased after mandibular setback surgery, and changes in the surrounding structures were identified through posteroinferior movement of the hyoid bone during long-term follow-up. Therefore, postoperative obstructive sleep apnea should be considered in patients who plan to undergo mandibular setback surgery, and necessary modifications to the treatment plan should also be considered.

Changes of Pharyngeal Airway Space after Mandibular Setback Surgery in Computed Tomography Images

Comparison of Posterior Pharyngeal Airway Space at Sitting and Supine Positions in the PACU after Uvulopalatopharyngoplasty in Patients with Obstructive Sleep Apnea Syndrome / 대한마취과학회지

BACKGROUND: Uvulopalatopharyngoplasty (UPPP) is one of the most common treatments for patients with obstructive sleep apnea syndrome (OSAS) who suffer from repetitive apnea and oxygen desaturation during sleep. It is important to properly manage the patient's airway in the PACU after surgery in order to prevent potential airway-related postoperative complications. METHODS: 20 patient cases of ASA I or II who were over 20 years old and had undergone UPPP under general anesthesia were reviewed. In PACU, Posterior pharyngeal airway space (PAS) was measured on a lateral cranial radiograph at both supine and sitting positions and the blood pressure and oxygen saturation were measured. RESULTS: PAS significantly increased in the sitting position (avg. 11.7 mm in supine, 15.7 mm in sitting, P < 0.05) but there was no influence on the blood pressure or oxygen saturation. CONCLUSIONS: PAS is associated with the patency of the airway and the increase of PAS in patients in the sitting position while in the PACU is helpful to airway management following UPPP.

A study of upper airway dimensional change according to maxillary superior movement after orthognathic surgery / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to evaluate the upper airway dimensional change according to maxillary superior movement after orthognathic surgery and to identify the relationship between the amount of maxillary movement and upper airway dimensional changes. METHODS: The samples consisted of 24 adult patients (9 males and 15 females) who had a skeletal discrepancy and had received presurgical orthodontic treatment. They underwent Le Fort I superior impaction osteotomy and mandibular setback surgery. Cephalometric x-rays were taken at 3 stages - T0 (before orthognathic surgery), T1 (just or within 2 weeks after orthognathic surgery), T2 (6 months after surgery) RESULTS: 1, Pharyngeal airway space (PAS (R)-nasopharynx) was decreased after surgery (T1) but recovered at 6 months after surgery; 2, Pharyngeal airway space (PAS (NL)-palatal plane) was increased after surgery and at 6 months after surgery; 3, Pharyngeal airway space (PAS (OL)-occlusal plane) was increased at T1 and was decreased at T2; 4, Soft palate thickness was increased at T1 but it became the same or thinner at T2; 5, There is no statistically significant relation between the amount of maxillary superior movement and pharyngeal airway space. CONCLUSIONS: These findings suggested that the maxillary superior movement of about an average of 4.40 +/- 1.14 mm did not affect upper pharyngeal airway space changes.

A Cephalometric Study on Changes in Pharyngeal Airway Space, Tongue and Hyoid Bone Positions Following the Surgical Correction of Mandibular Prognathism

PURPOSE: This study was aimed at measuring the changes in the hyoid bone position, tongue position, and pharyngeal airway space in subjects with mandibular setback osteotomies. METHODS: Twenty patients were evaluated retrospectively for their changes in pharyngeal airway space, tongue and hyoid bone positions. All patients underwent surgical mandibular setback using bilateral sagittal split osteotomies. The cephalometric analysis was performed preoperatively, and 1 week, 3-6 months, and 1 year postoperatively. RESILT: The hyoid bone moved inferiorly and posteriorly immediately after surgery, and it returned to the preoperative position during follow-up period. The nasopharyngeal airway space was not significantly changed after surgery. A considerable decrease in the oropharyngeal and hypopharyngeal airway spaces following mandibular setback surgery was found. The upper and lower tongue was posteriorly repositioned immediately after surgery. During follow-up period, the hypopharyngeal airway space and lower tongue posture returned to the preoperative positions, but the oropharyngeal airway space and upper tongue posture were not significantly changed. The position of pogonion remarkably changed to backward immediately after surgery, but slightly anterior advancement was found during follow-up period. CONCLUSION: Immediately after mandibular setback surgery, the oropharyngeal and hypopharyngeal airway spaces obviously decreased due to posterior and inferior repositions of the tongue and hyoid bone. During follow-up period, lower tongue and hyoid bone returned to the preoperative positions, it was related to advancement of the pogonion in this period. The narrowing of the oropharyngeal airway space and posterior movement of the upper tongue posture were relatively permanent after mandibular setback surgery. We suspected this phenomenon had an influence on maintaining the total volume of oral cavity against mandibular setback.