• Archives of Plastic Surgery
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• v.38 no.6
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• pp.783-790
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• 2011

Purpose: The zygoma (Zygomaticomaxillary) complexes make up a large portion of the orbital floor and lateral orbital walls. Zygoma fracture frequently causes the posteromedial displacement of bone fragments, and the collapse or overlapping of internal orbital walls. This process consequently can lead to the orbital volume change. The reduction of zygoma in an anterolateral direction may influence on the potential bone defect area of the internal orbital walls. Thus we performed the quantitative analysis of orbital volume change in zygoma fracture before and after operation. Methods: We conducted a retrospective study of preoperative and postoperative three-dimensional computed tomography scans in 39 patients with zygoma fractures who had not carried out orbital wall reconstruction. Orbital volume measurement was obtained through Aquarius Ver. 4.3.6 program and we compared the orbital volume change of injured orbit with that of the normal contralateral orbit. Results: The average orbital volume of normal orbit was 19.68 $cm^3$. Before the operation, the average orbital volume of injured orbit was 18.42 $cm^3$. The difference of the orbital volume between the injured orbit and the normal orbit was 1.18 $cm^3$ (6.01%) on average. After operation, the average orbital volume of injured orbit was 20.81 $cm^3$. The difference of the orbital volume between the injured orbit and the normal orbit was 1.17 $cm^3$ (5.92%) on average. Conclusion: There are considerable volume changes in zygoma fracture which did not accompany internal orbital wall fracture before and after operation. Our study reflects the change of bony frame, also that of all parts of the orbital wall, in addition to the bony defect area of orbital floor, in an isolated zygoma fracture so that it evaluates orbital volume change more accurately. Thus, the measurement of orbital volume in isolated zygoma fractures helps predict the degree of enophthalmos and decide a surgical plan.

• Archives of Craniofacial Surgery
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• v.23 no.6
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• pp.262-268
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• 2022

Background: To compare the sensory change and recovery of infraorbital area associated with zygomaticomaxillary and orbital floor fractures and their recoveries and investigate the factors that affect them. Methods: We retrospectively reviewed 652 patients diagnosed with zygomaticomaxillary (n= 430) or orbital floor (n= 222) fractures in a single center between January 2016 and January 2021. Patient data, including age, sex, medical history, injury mechanism, Knight and North classification (in zygomaticomaxillary fracture cases), injury indication for surgery (in orbital floor cases), combined injury, sensory change, and recovery period, were reviewed. The chi-square test was used for statistical analysis. Results: Orbital floor fractures occurred more frequently in younger patients than zygomaticomaxillary fractures (p< 0.001). High-energy injuries were more likely to be associated with zygomaticomaxillary fractures (p< 0.001), whereas low-energy injuries were more likely to be associated with orbital floor fractures (p< 0.001). The sensory changes associated with orbital floor and zygomaticomaxillary fractures were not significantly different (p= 0.773). Sensory recovery was more rapid and better after orbital floor than after zygomaticomaxillary fractures; however, the difference was not significantly different. Additionally, the low-energy group showed a higher incidence of sensory changes than the high-energy group, but the difference was not statistically significant (p= 0.512). Permanent sensory changes were more frequent in the high-energy group, the difference was statistically significant (p= 0.043). Conclusion: The study found no significant difference in the incidence of sensory changes associated with orbital floor and zygomaticomaxillary fractures. In case of orbital floor fractures and high-energy injuries, the risk of permanent sensory impairment should be considered.

• Archives of Craniofacial Surgery
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• v.10 no.1
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• pp.7-13
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• 2009

Purpose: Endoscopic transnasal correction of the medial orbital fractures cannot be enable to confirm the reduction degree of orbital volume without imaging modalities. We have intended through this study to make a quantative analysis of preoperative orbital volume increment and the reduction degree of that after ethmoidal sinus packing by using CT scan. Methods: In this retrospective study, 22 patients were selected to evaluate the postoperative volume reduction, who took 2 CT scans which are pre- and postoperative under the same protocol. The postoperative CT scan was carried out in about 5 days after the operation with the packing inserted into ethmoidal sinus. The length of bony defect on each section was measured by PACS program and the area of defect was calculated by summing lengths on each section multiplied by the thickness of the section. When the outline of orbit on the slice is drawn manually with a cursor, PACS program measures the area automatically. Orbital volume was calculated from the sum of the area multiplied by the section thickness. Results: The mean dimension of fractured walls was $2.86{\pm}0.99cm^2$. The mean orbital volume of the unaffected orbits was $22.89{\pm}2.15cm^3$ and that of the affected orbits was $25.62{\pm}2.82cm^3$. The mean orbital volume increment of the affected orbits was $2.73{\pm}1.13cm^3$. After surgery, the mean orbital volume of the unaffected orbits was $22.46{\pm}2.73cm^3$ and the mean orbital volume decrease on the surgical side was $2.98{\pm}1.07cm^3$. The estimated correction rate was 118.30%. Conclusion: The orbital volume increment in fractured orbit showed linear correlation with the dimension of fractured area. The orbital volume changes after ethmoidal sinus packing also showed linear correlation with orbital volume increment in fractured orbit. This study showed the regressive linear correlation between the increment of orbital volume and the correction rate. To evaluate the maintenance of reduction state, we think that the further study should be done for comparative analysis of orbital volume change after removal of packing.

• Archives of Plastic Surgery
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• v.36 no.5
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• pp.617-622
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• 2009

Purpose: Endoscopic transnasal correction of the blowout fractures has many advantages over other techniques. But after removal of packing material, there were some patients with recurrence of preoperative symptoms. Authors tried to make a quantitative anterograde analysis of orbital volume change over whole perioperative period which might be related with recurrence of preoperative symptoms. Methods: 10 patients with pure medial wall fracture(Group I) and 10 patients with medial wall fracture combined with fracture of orbital floor(Group II) were selected to evaluate the final orbital volume change, who took 3 CT scans, pre-, postoperative and 4 months after packing removal. By multiplying cross - section area of orbit in coronal view with section thickness, orbital volume were calculated. Then, mean orbital volume increment after trauma, mean orbital volume decrement after endoscopic correction and volume increment after packing removal were found out. And we tried to find correlations between type of fracture, initial correction rate and final correction rate. Results: The mean orbital volume increment of the fractured orbits were 7.23% in group I and 13.69% in group II. After endoscopic surgery, mean orbital volume decrement were 11.0% in group I and 12.46% in group II. Mean volume increment after packing removal showed 3.10% in group I and 6.50% in group II. The initial correction rate(%) showed linear correlation with final correction rate(%) after packing removal. And there were negative linear correlation between increment percentage of orbital volume by fracture and final correction rate(%). Conclusion: Orbital volume was proved to be increasing after removal of packing or foley catheter and it was dependent upon type of fracture. Overcorrection should be done to improve the final result of orbital blowout fracture especially when there are severe fracture is present.

• The korean journal of orthodontics
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• v.5 no.1
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• pp.51-56
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• 1975

In orthodontic field, the study on gnathostatic model is very important to the diagnosis and analysis of malocclusion. The purpose of this study is to observe that relation of orbital plane and upper canine in Koreans. We selected 230 cases with normal occlusion, 124 male and 106 female cases aged from 12 years to 25 years, to prepare 230 gnathostatic models, and measured the distance from midpoint of mesio-distal distance of upper canine to orbital plane in gnathostatic model. The results obtained were as follows: 1) The mean value of the distance from upper canine to orbital plane showed no significant change with age. 2) The mean value of the distance from the upper canine to orbital plane was -3.11mm in male and -3.84mm in female. 3) The orbital plane passed through the upper canine in normal occlusion of Koreans.

• Transactions of Materials Processing
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• v.14 no.1 s.73
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• pp.29-36
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• 2005

In this paper, a useful rigid-plastic finite element method with various numerical schemes is presented for simulation of an orbital forming process. A new approach to reduce volume change during simulation is presented and an approximation method to reduce computational time is also presented. An actual orbital forming process found in a bearing making industry is simulated by the presented approach. The simulated results of the orbital forming process are compared with the experimental results.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.367-377
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• 2015

Atmospheric drag force is an important source of perturbation of Low Earth Orbit (LEO) orbit satellites, and solar activity is a major factor for changes in atmospheric density. In particular, the orbital lifetime of a satellite varies with changes in solar activity, so care must be taken in predicting the remaining orbital lifetime during preparation for post-mission disposal. In this paper, the System Tool Kit (STK$^{(R)}$) Long-term Orbit Propagator is used to analyze the changes in orbital lifetime predictions with respect to solar activity. In addition, the STK$^{(R)}$ Lifetime tool is used to analyze the change in orbital lifetime with respect to solar flux data generation, which is needed for the orbital lifetime calculation, and its control on the drag coefficient control. Analysis showed that the application of the most recent solar flux file within the Lifetime tool gives a predicted trend that is closest to the actual orbit. We also examine the effect of the drag coefficient, by performing a comparative analysis between varying and constant coefficients in terms of solar activity intensities.

• Journal of the Korean Ceramic Society
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• v.42 no.5 s.276
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• pp.304-307
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• 2005

The possible configurations of hydroxyl group in hexagonal hydroxyapatite were identified through molecular orbital calculation. The molecular orbital interaction between O and H in hydroxyl column was analyzed using charge variation and Bond Overlap Population (BOP). We supposed 5 kinds of O-H bond configurations as cluster types of I, II, III, IV, and V. Mulliken's population analysis was applied to evaluate ionic charges of O, H, P, and Ca ions, and BOPs (Bond Overlap Populations) in order to discuss the bond strength change by the atomic arrangement. The stability of each O-H bond configuration was analyzed using bond overlap and ionic charge.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2527-2530
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• 2010

The stereoselectivity of the intramolecular Diels-Alder reactions of 1 and its derivatives were investigated by ab initio calculations. The stereoselectivity mainly originates from the steric repulsion and the orbital interactions. The additional s-cis and s-trans conformations by introducing the carbonyl group at the neighbor of diene or dienophile may change the stereoselectivity, hence this kind of substitution can be utilized for stereoselectivive asymmetric synthesis.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.24-24
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• 2003

We present preliminary results about the quasi-simultaneous near-infrared light curves of the long-period eclipsing polar V1309 Ori in the J, H, K', and K bands with almost complete orbital phase coverage using the CFHT-IR camera. The optical light curve in the V and R bands, obtained by 1.8m Telescope at BOAO, will be also presented. The shape and the amplitude of the orbital light curve change significantly from optical to near-infrared wavelengths.