• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.401-406
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• 2011

Purpose: The purpose of this study was to investigate changes in the position of the hyoid bone and soft palate and the amount of airway space after bilateral sagittal split ramus osteotomy (B-SSRO). Methods: This study is a review of lateral cephalometric tracings of 30 patients who underwent B-SSRO with setbacks at Kyunghee Dental Hospital from 2005 to 2009. Lateral cephalograms were taken before (T0), within one month (T1), and more than six months after the surgery (T2). Results: The hyoid bone at T1 changed significantly towards the inferoposterior position. At T2, it had significantly moved superiorly, but not anteriorly. At T1, the nasopharyngeal space, extending from the posterior nasal spine to the posterior pharyngeal space, decreased significantly, but did not show a significant increase at T2. The nasopharyngeal space, extending from the middle of soft palate to the posterior pharyngeal space, decreased significantly at T1, but did not show a significant decrease at T2. The oropharyngeal airway space decreased significantly at T1 and did not return to its original position at T2. The hypopharyngeal space, extending from the anterior to the posterior pharyngeal space at the level of the most anterior point of the third cervical vertebrae, slightly decreased at T1, but the amount was insignificant; however, the amount of decrease at T2 was significant. The hypopharyngeal space extending from the anterior to the posterior pharyngeal space at the level of the lowest point of the third cervical vertebrae, decreased significantly at T1 but returned to its original position at T2. Conclusion: B-SSRO changes the position of the hyoid bone and muscles inferoposteriorly. These change allows enough space for the tongue and prevent airway obstruction. Airway changes may be related to post-operative edema, posterior movement of the soft palate, anteroposterior movement of the hyoid bone, or compensation for decreased oral cavity volume. The position of the pogonion which measures anterior relapse after surgery did not show significant differences during the follow-up period.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.5
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• pp.185-191
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• 2014

Purpose: Although there have been several studies of reduced airway space after mandibular setback surgery using the sagittal split ramus osteotomy technique, research on the risk factors for changes of the airway space is lacking. Therefore, this study was performed to examine airway changes and the position of the hyoid bone after orthognathic surgery, and to assess possible risk factors. Methods: In this retrospective study, 50 patients who underwent posterior displacement of the mandible by the bilateral sagittal split ramus osteotomy technique were included. Changes of the position of the hyoid bone and the airway space were analyzed over various follow-up periods, using cephalometric radiography taken preoperatively, immediately after surgery, eight weeks after surgery, six months after surgery, and one year after surgery. To identify risk factors, multiple regression analysis of age, gender, body mass index (BMI), posterior mandibular movement, and the presence of genioplasty was performed. Results: Inferor and posterior movement of the hyoid bone was observed postoperatively, but subsequent observations showed regression towards the anterosuperior aspect. The airway space also significantly decreased after surgery (P<0.05), and increased slightly up until six months after surgery. The airway space significantly decreased (${\beta}=0.47$, P<0.01) as the amount of mandibular setback increased. However, age, sex, BMI, and presence of genioplasty were not associated with airway reduction. Conclusion: The amount of mandibular set back was significantly associated with postoperative reduction of airway space. It is necessary to establish a treatment plan considering this factor.

• Physical Therapy Korea
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• v.22 no.1
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• pp.103-109
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• 2015

Although the relationship between temporomandibular disorder and forward head posture (FHP) is controversial, it is generally accepted that altered head posture can affect mandible position and masticatory muscles activity. Because suprahyoid (SH) and infrahyoid (IH) muscles are stretched by increased passive tension in FHP, this study investigated their activity during mouth opening in FHP compared to neutral head posture (NHP). Twenty healthy subjects (10 males and 10 females) participated in this study. Head postures were evaluated with a cervical range of motion instrument. Electromyography (EMG) activity of bilateral SH and IH muscles was measured while an open mouth was maintained at each head posture. Paired t-test was used to identify significant differences in normalized EMG activity between head postures. Statistical significance was set at .01. Results showed the normalized EMG activity of SH and IH muscles were significantly lower in FHP compared to NHP. This finding indicates that FHP affects the EMG activity of hyoid muscles when they are stretched.

• 대한치과교정학회:학술대회논문집
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• 2004.11a
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• pp.29-30
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• 2004

• The Journal of the Korean dental association
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• v.56 no.5
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• pp.278-286
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• 2018

Food intake and swallowing are complicated and intriguing series of movements involving voluntary and involuntary activities of cranial and spinal nerves and muscles. They have two most important functions, that is, food passage from the oral cavity to stomach and airway protection. Tongue, buccinators, and hyoid bone and its muscular attachments are anatomic structures for swallowing of special interests. The swallowing process of liquid is commonly divided into oral preparatory, oral propulsive, pharyngeal, and esophageal stages according to the location of the bolus. The movement of the food in the oral cavity and to the oropharynx differs between eating solid food and drinking liquid.

• Korean Journal of Bronchoesophagology
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• v.13 no.1
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• pp.51-54
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• 2007

Laryngeal trauma is an uncommon injury but can be life-threatening event. So, early diagnosis is important for appropriate surgical management and better outcome. Because there have been some controversies about Initial airway management, appropriate diagnostic evaluation, operative indication and timing, operative technique, it is difficult to make a common management pathway in laryngeal trauma. A case of laryngeal trauma with thyroid cartilage and hyoid bone fracture is presented with a brief review of literature.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1991.06a
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• pp.13-13
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• 1991

후두는 호흡기가 시작되는 부위로 후두의 태생학적 연구는 타장기에서와 같이 정상 후두의 해부학적 이해, 후두 기형의 병인의 이해 및 치료에 기초 자료가 된다. 그러나 사람 배아의 후두 발생에 관한 연구는 재료확보가 용이하지 않고 해부학적 난이성으로 매우 드물다. 이에 저자는 사람 배아의 후두 발달을 연구하고자 배령이 확인된 20례의 배아(배령 4 주에서 8 주 까지)의 연속절편에서 광학현미경하에 후두 발달의 형태학적 관찰을 시행하여 다음과 같은 결과를 얻었다. 1. 배령 4 주에 median pharyngeal groove, laryngotracheal sulcus 와 tracheoesophageal septum 이 관찰되었다. 2. 배령 5 주에 hypopharyngeal eminence, epithelial lamina of larynx와 arytenoid swelling이 관찰되었다. 3. 배령 6 주에 hyoid condensation과 tracheoesophagealfistula가 관찰되었다. 4. 배령 7 주에 epiglottis 가 확인되었고 hyoid bone, thyroid lamina 와 cricoid cartilage 의 condensation 및 muscular condensation 이 관찰되었다. 5. 배령 8 주에 laryngeal cartilage의 chondrification과 ventricle이 관찰되었으며, vestibulotracheal canal과 pharyngotracheal canal 의 교통은 관찰되지 않았다.

• Korean Journal of Bronchoesophagology
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• v.3 no.2
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• pp.327-331
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• 1997

One of the most difficult airway problems is a subglottic stenosis combined with a tracheal stenosis. Laryngotracheal stenosis has not been completely solved with classic methods like cricotracheal split with autogenous cartilage graft, thyrotracheal anastomosis, and free hyoid or hyoid-sternohyoid myo-osseous flap reconstruction. A 28-near-old male patient who had had laryngotracheal stenosis was successfully treated by laryngotracheal reconstruction using vascularized clavicle. This method has a several advantages: the vascularized clavicle harvesting in the same operative fields, one stage operation, less restenosis due to plentyful blood supply, md prevention of airway collapse due to a clavicle provided framework. It is too early to make a definite conclusion, but the authors suggested that this method could become one of the most effective methods of laryngotracheal stenosis.

• Journal of Korean society of Dental Hygiene
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• v.18 no.4
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• pp.525-533
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• 2018

Objectives: This retrospective study evaluated the changes in the airway width after the orthognathic surgery associated with the skeletal Class III malocclusion. Methods: The lateral cephalograms of 30 adult patients were taken before and immediately after the operation, and after the orthodontic treatment. The angles and distances of them were measured and compared. Results: Before the surgery, the mean value of mandibular (S-B) setback was 9.66 mm, and moved by 1.56 mm anteriorly after the orthodontic treatment. The ANB increased by 5.42 degrees, since then it decreased by 0.68 degree. The hyoid bone (S-APH) moved by 5.05 mm posteriorly, but then moved by 2.26 mm anteriorly. The soft tissue width of laryngeal pharynx (apw2-ppw2) was narrowed by 1.04 mm, and decreased by additional 0.83 mm after the orthodontic treatment. Conclusions: As the mandible was moved back, the location of hyoid bone and laryngeal pharynx were moved backward.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.58.1-58.8
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• 2019

Background: The aim of this study is to investigate the relationship between gender-specific and obesity-related airway anatomy in patients with obstructive sleep apnea (OSA) by using cephalometric analyses. Methods: We retrospectively evaluated 206 patients with suspected OSA undergoing polysomnography and anthropometric measurements such as body mass index, neck circumference, and waist-hip ratio. We checked lateral cephalometry to measure tissue landmarks including angle from A point to nasion to B point (ANB), soft palate length (SPL), soft palate thickness (SPT), retropalatal space (RPS), retrolingual space (RLS), and mandibular plane to hyoid (MPH). Results: Male with OSA showed significantly increased SPL (P = .006) compared with controls. SPL and MPH had significant correlation with apnea-hypopnea index (AHI) and central obesity. Female with OSA showed significantly increased ANB (P = .013) and SPT (P = .004) compared with controls. The receiver operating characteristic curves revealed that SPT in male and ANB and SPT in female were significant in model 1 (AHI ≥ 5) and model 2 (AHI ≥ 15). MPH was also significant for male in model 2. Conclusion: Male and female with OSA had distinct anatomic features of the upper airway and different interactions among soft palate, mandible, and hyoid bone.