• Journal of Chest Surgery
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• v.28 no.8
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• pp.766-771
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• 1995

The trachea is defined as the airway from the inferior border of the cricoid cartilage to the top of the carinal spur. This paper would confirm the normal tracheal length of Korean adults through the actual measurement using the fiberoptic bronchoscopy. The subjects of this study were 25 patients, 13 males and 12 females between the age of 20 to 69 without abnormality on the neck, trachea, mediastinum and lung pharenchyme on the preoperative chest X-ray, who received the operations from the period of July to September, 1994. For those patients who had heart diseases, the cardiothoracic ratio was below 50%. The measurement was performed on the patients with endotracheal intubation under the general anesthesia in supine and neutral position. The tracheal length was calculated by the difference between the length from the tip of the endotracheal tube [E-tube to carina and to the needle which was inserted into the E-tube at the lower border of the palpated cricoid cartilage, by inserting the broncoscopy through the E-tube. The result was as follow : 1 The measured tracheal length for men was 11.8 0.2 cm[mean standard deviation and women was 10.5 0.3 cm, and that was longer than this [p<0.01 . The average was 11.2 1.0 cm and the standard error was 0.20 cm. 2 According to the correlation between the tracheal length to weight, height[Ht , age, and body surface area[BSA respectively, the Ht [p=0.003 , age [p=0.055 , and the BSA[p=0.017 were significant, while weight was not [p=0.314 . 3 From the regression analysis of the tracheal length[T.L. to the Ht, Age, and the BSA which were significant, the following equation was derived.i Ht : T.L.= -1.29 + 0.076 x Ht [P=0.003 ii Age: T.L.= 10.04 + 0.028 x Age [P=0.055 iii BSA : T.L.= 5.60 + 3.48 x BSA [P=0.017 iv In multi-regression : T.L. = -4.15 + 0.034 x Age + 0.085 x Ht [P=0.0002]

• Journal of Korean Neurosurgical Society
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• v.50 no.4
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• pp.341-347
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• 2011

Objective : The purpose of this retrospective study was to evaluate the efficacy and safety of atlantoaxial stabilization using a new entry point for C2 pedicle screw fixation. Methods : Data were collected from 44 patients undergoing posterior C1 lateral mass screw and C2 screw fixation. The 20 cases were approached by the Harms entry point, 21 by the inferolateral point, and three by pars screw. The new inferolateral entry point of the C2 pedicle was located about 3-5 mm medial to the lateral border of the C2 lateral mass and 5-7 mm superior to the inferior border of the C2-3 facet joint. The screw was inserted at an angle $30^{\circ}$ to $45^{\circ}$ toward the midline in the transverse plane and $40^{\circ}$ to $50^{\circ}$ cephalad in the sagittal plane. Patients received followed-up with clinical examinations, radiographs and/or CT scans. Results : There were 28 males and 16 females. No neurological deterioration or vertebral artery injuries were observed. Five cases showed malpositioned screws (2.84%), with four of the screws showing cortical breaches of the transverse foramen. There were no clinical consequences for these five patients. One screw in the C1 lateral mass had a medial cortical breach. None of the screws were malpositioned in patients treated using the new entry point. There was a significant relationship between two group (p=0.036). Conclusion : Posterior C1-2 screw fixation can be performed safely using the new inferolateral entry point for C2 pedicle screw fixation for the treatment of high cervical lesions.

• Imaging Science in Dentistry
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• v.38 no.1
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• pp.49-56
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• 2008

Purpose: Diagnostic estimation of destruction and formation of bone has the typical limit according to capacity of x-ray generator and image detector. So the aim of this study was to find out how much it can reproduce the shape and the density of bone in the case of using recently developed dental type of cone beam computed tomography, and which image is applied by new detector and mathematic calculation. Materials and Methods: Cone beam computed tomography (PSR 9000N, Asahi Roentgen Ind. Co., Ltd., Japan) and soft x-ray radiography were executed on dry mandible that was already decalcified during 5 hours, 10 hours, 15 hours, 20 hours, and 25 hours. Estimating and comparing of those came to the following results. Results: The change of inferior border of mandible and anterior border of ramus in the region of cortical bone was observed between first 5 and 10 hours of decalcification. The reproduction of shape and density in the region of cortical bone and cancellous bone can be hardly observed at cone beam computed tomography compared with soft x-ray radiography. The difference of decrease of bone density according to hours of decalcification increase wasn't reproduced at cone beam computed tomography compared with soft x-ray radiography. Conclusion: CBCT images revealed higher spatial resolution. However, contrast resolution in region of low contrast sensitivity is the inferiority of images' property.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.4
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• pp.485-489
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• 2008

Basal cell nevus syndrome is a hereditary disease of an autosomal dominant trait with variable conditions such as basal cell carcinomas of the skin, deformity of rib, fusion of vertebrae, mental retardation, hypertelorism, and multiple odontogenic keratocysts. A 32 years old man with pus discharge from fistula on the vestibule of left upper 1st molar visited to Chosun University Dental Hospital. Radiographic evaluation revealed multiple maxillary and mandibular cysts that had multilocular radiolucency on left mandibular body area, thining of inferior border of left border of ramus and well defined unilocular radiolucency above right upper 1st and 2nd molar and from left upper 1st premolar to 2nd molar. In chest PA view, he had a forked rib in the left 4th rib and in skull PA view the calcification of falx cerebri was observed. There was not any skin lesion. After the preliminary evaluation, the patient was diagnosed with basal cell nevus syndrome and he underwent marsupialization for decreasing the size of cystic lesion and came to hospital for dressing 3days a week. As time goes by, the size of lesion decreased. So, one and half year after marsupialization, he underwent cyst enucleation and iliac bone graft for the mandibular lesion and buccal fat pad grafts for the maxillary lesions. After the surgery, the patient experienced normal healing without any complications and he is on long-term follow-up.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.2
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• pp.27-47
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• 1997

The purpose of this study was to evaluate the accuracy and usefulness of spiral tomography through the comparison and analysis of SCANORA cross-sectional tomographs and DentaScan computed tomographic images of dry mandibles taken by a SCANORA spiral tomographic machine and a computed tomographic machine. Thirty-one dry mandibles with full or partial edentulous areas were used. To evaluate the possible effect of location in the edentulous area, it was divided into 4 regions of Me (region of mental foramen), MI (the midportion between Me and M2), M2 (the midportion between mental foramen and mandibular foramen) and S (the midportion of the mandibular symphysis). A ZPC column (sized 4 mm x 5 mm) was seated on the edentulous regions of Me, MI, M2 and S using the acrylic stent. Then SCANORA spiral tomography and computed tomography were taken on the edentulous regions which contained the ZPC column. The ZPC columns and cross-sectional images of the mandible were measured in the radiographs by three observers and the differences between the two imaging modalities were analysed. The results were as follows: 1. In comparing the actual measurements of the ZPC column and measurements in the radiographs, the mean error of the DentaScan computed tomography was 0.07 mm in vertical direction and -0.06 mm in horiwntal direction, while the mean error of the SCANORA spiral tomography was 0.06 mm in vertical direction and -0.12 mm in horizontal direction. There was a significant difference between the two radiographic techniques in the horizontal measurement of the ZPC column of the symphysis region (p<0.05). But there was no significant difference in the measurements of other regions (p>0.05). 2. In measurements of the distance from the alveolar crest to the inferior border of the mandible (H), and of the distance from the alveolar crest to the superior border of the mandibular canal (Y), there was no significant difference between the two radiographic techniques (p>0.05). 3. In measurements of the distance from the lingual border of the mandible to the buccal border of the mandible (W), and of the distance from the lingual border of the mandible to the lingual border of the mandibular canal (X), there was a significant difference between the two radiographic techniques in measurements of the midportion between the mental foramen and the mandibular foramen (M2) (p<0.05). But there were no significant differences in measurements of the other regions of symphysis (S), mental foramen (Me), the first one-fourth portion between the mental foramen and the mandibular foramen (M1) (p>0.05). 4. Considering the mean range of measurements between observers, the measurements of SCANORA spiral tomography showed higher value than those of DentaScan computed tomography, except in measurements of symphysis (S). 5. On the detectability of the mandibular canal, there was no significant difference between the two radiographic techniques (p>0.05). In conclusion, SCANORA spiral tomography demonstrated a higher interobserver variance than that of DentaScan computed tomography for implant site measurements in the posterior edentulous area of the mandible. These differences were mainly the result of difficulty in the detection of the border of the mandible in SCANORA spiral tomography. But considering the cost and the radiation exposure, SCANORA spiral tomography can be said to be a relatively good radiographic technique for implant site measurement.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.297-306
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• 1991

The purpose of this study is to improve the availabilities of radiographic technics as diagnostic methods to evaluate maxillary sinus in dental clinic. For the morphologic study of maxillary sinus, 20 dry maxillas were used and intraoral standard views, orthopantomograms, and skull P-A views were taken. For measuring the vertical image magnification rates, 5 sites in maxillary molar regions of 5 dry mandibles were selected radndomly and 25 wires of the determined sizes for selected portions were attached to the sites, after then, intraoral radiograms with bisecting technic and orthopantomograms were taken. The acquired results were as follows: 1. The anterior extension of the maxillary sinus on orthopantomogram was the distal side of the canine in 45.45% of subjects, the mesial side of the canine in 27.27%, the lateral incisor in 9.09%, the mesial side of the 1st premolar in 9.09%, and the mesial side of the 2nd pre-molar in 9.09%. 2. The positional relationship between the floor of maxillary sinus and the apex of alveolar socket revealed superimposed type in 58.3% of subjects, approached type in 33.3%, and separated type in 8.4%. 3. The morphology of inferior border of maxillary sinus was simple V or U shape in edentulous stage and V or wide U shape in alveolar socket stage. 4. The vertical image length on intraoral film taken by bisecting technic was magnified by 27.23% on the average and the length on orthopantomogram by 12.35%. 5. The inferior borders of maxillary sinus coinciding with each of the areas bearing the anterior and the posterior teeth on skull P-A view were determined.

• Korean Journal of Cleft Lip And Palate
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• v.10 no.2
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• pp.67-74
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• 2007

After Tennison introduced a triangular flap method which, for the first time, preserved the Cupid's bow, Randall gave this method a sound mathematical basis. This method is also called as an inferior triangular cheiloplasty which is characterized by making a small triangular flap from the lateral border of cleft destined to be fitted into an incision on the medial side of cleft. He postulated that the height obtained was equal to the sum of the median of the two triangles used in the cheiloplasty. Using this technique, a 22 month-old male patient with incomplete unilateral cleft lip was corrected primarily. The deviation of the columella and flattening of the nostril on the cleft side were minimal. The operation was done under general anesthesia and patient was healed uneventfully. We tried to improve the symmetry and esthetic feature of philtrum, nostril sill, alar-facial groove, preventing the notch formation on the nostril floor, and to reconstruct the muscle sling in the upper part of lip. The shape of Cupid's bow was restored, and the symmetry of columella was regained as a result. In summary, the inferior triangular cheiloplasty is effective to correct the primary unilateral cleft lip, results in the restoration of favorable anatomy and function.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.25.1-25.9
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• 2015

Background: During the orthognathic surgery, it is important to know the exact anatomical location of the mandibular foramen to achieve successful anesthesia of inferior alveolar nerve and to prevent damage to the nerves and vessels supplying the mandible. Methods: Cone-beam computed tomography (CBCT) was used to determine the location of the mandibular foramen in 100 patients: 30 patients with normal occlusion (13 men, 17 women), 40 patients with skeletal class II malocclusion (15 men, 25 women), 30 patients with skeletal class III malocclusion (17 men, 13 women). Results: The distance from the anterior border of the mandibular ramus to mandibular foramen did not differ significantly among the three groups, but in the group with skeletal class III malocclusion, this distance was an average of $1.43{\pm}1.95mm$ longer in the men than in the women (p < 0.05). In the skeletal class III malocclusion group, the mandibular foramen was higher than in the other two groups and was an average of $1.85{\pm}3.23mm$ higher in the men than in the women for all three groups combined (p < 0.05). The diameter of the ramus did not differ significantly among the three groups but was an average of $1.03{\pm}2.58mm$ wider in the men than in the women for all three groups combined (p < 0.05). In the skeletal class III malocclusion group, the ramus was longer than in the other groups and was an average of $7.9{\pm}3.66mm$ longer in the men than women. Conclusions: The location of the mandibular foramen was higher in the skeletal class III malocclusion group than in the other two groups, possibly because the ramus itself was longer in this group. This information should improve the success rate for inferior alveolar nerve anesthesia and decrease the complications that attend orthognathic surgery.

• Journal of Korean Neurosurgical Society
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• v.48 no.5
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• pp.406-411
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• 2010

Objective : Esophageal/hypopharyngeal injury can be a disastrous complication of anterior cervical surgery. The amount of hypopharyngeal wall exposure within the surgical field has not been studied. The objective of this study is to evaluate the chance of hypopharyngeal wall exposure by measuring the amount of axial rotation of the thyroid cartilage (ARTC) and posterior projection of the hypopharynx (PPH). Methods : The study was prospectively designed using intraoperative ultrasonography. We measured the amount of ARTC in 27 cases. The amount of posterior projection of the hypopharynx (PPH) also was measured on pre-operative CT and compared at three different levels; the superior border of the thyroid cartilage (SBTC), cricoarytenoid joint and tip of inferior horn of the thyroid cartilage (TIHTC). The presence of air density was also checked on the same levels. Results : The angle of ARTC ranged from $-6.9^{\circ}$ to $29.7^{\circ}$, with no statistical difference between the upper and lower cervical group. The amount of PPH was increased caudally. Air densities were observed in 26 cases at the SBTC, but none at the TIHTC. Conclusion : Within the confines of the thyroid cartilage, surgeons are required to pay more attention to the status of hypopharynx/esophagus near the inferior horn of the thyroid cartilage. The hypopharynx/esophagus at the TIHTC is more likely to be exposed than at the upper and middle part of the thyroid cartilage, which may increase the risk of injury by pressure. Surgeons should be aware of the fact that the visceral component at C6-T1 surgeries also rotates as much as when the thyroid cartilage is engaged with a retractor. The esophagus at lower cervical levels warrants more careful retraction because it is not protected by the thyroid cartilage.

• Journal of Periodontal and Implant Science
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• v.50 no.1
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• pp.28-37
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• 2020

Purpose: The aim of our study was to determine the prevalence and degree of lingual concavities in the first molar region of the mandible to reduce the risk of perforating the lingual cortical bone during dental implant insertion. Methods: A total of 163 suitable cross-sectional cone-beam computed tomography images of edentulous mandibular first molar regions were evaluated. The mandibular morphology was classified as a U-configuration (undercut), a P-configuration (parallel), or a C-configuration (convex), depending on the shape of the alveolar ridge. The characteristics of lingual concavities, including their depth, angle, vertical location, and additional parameters, were measured. Results: Lingual undercuts had a prevalence of 32.5% in the first molar region. The mean concavity angle was 63.34°±8.26°, and the mean linear concavity depth (LCD) was 3.03±0.99 mm. The mean vertical distances of point P from the alveolar crest (Vc) and from the inferior mandibular border were 9.39±3.39 and 16.25±2.44, respectively. Men displayed a larger vertical height from the alveolar crest to 2 mm coronal to the inferior alveolar nerve (Vcb) and a wider LCD than women (P<0.05). Negative correlations were found between age and buccolingual width at 2 mm apical to the alveolar crest, between age and Vcb, between age and Vc, and between age and LCD (P<0.05). Conclusions: The prevalence of lingual concavities was 32.5% in this study. Age and gender had statistically significant effects on the lingual morphology. The risk of lingual perforation was higher in young men than in the other groups analyzed.