• Proceedings of The Korean Cleft Lip And Palate Association
• /
• 2005.06a
• /
• pp.23-24
• /
• 2005

• Archives of Craniofacial Surgery
• /
• v.18 no.3
• /
• pp.149-154
• /
• 2017

Computer-aided surgery (CAS) started being used for head and neck reconstruction in the late 2000s. Its use represented a paradigm shift, changing the concept of head and neck reconstruction as well as mandible reconstruction. Reconstruction using CAS proceeds through 4 phases: planning, modeling, surgery, and evaluation. Thus, it can overcome a number of trial-and-error issues which may occur in the operative field and reduce surgical time. However, if it is used for oncologic surgery, it is difficult to evaluate tumor margins during tumor surgery, thereby restricting pre-surgical planning. Therefore, it is dangerous to predetermine the resection margins during the presurgical phase and the variability of the resection margins must be taken into consideration. However, it allows for the preparation of a prebending plate and planning of an osteotomy site before an operation, which are of great help. If the current problems are resolved, its applications can be greatly extended.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.34D no.4
• /
• pp.54-61
• /
• 1997

In this paper, a new holographic display system that can in real-time reconstruct the complex hologram without the bias and the conjugate image, which is obtained form the modified triangular interferometer, is presented. The proposed system is made of adding liquid crystal displays(LCDs), a $\lambda$/2 wave plate, and a polarizing beam splitter to the conventional mach-zehnder interferontric configuration. We demonstrate through theoretical analysis and experiment that real-time image reconstruction from the complex hologram is possible using the proposed system.

• Journal of the Korean earth science society
• /
• v.35 no.5
• /
• pp.385-398
• /
• 2014

This study investigated students' alternative conceptions of plate boundaries and their conception revision according to the pattern of students' reasoning. Participants were twenty-two 10th grade high school students. All participants were asked to draw the three types of plate boundaries and to explain their drawings. Nine students participated in the reasoning activity. To this end, a semi-structured interview was conducted during which key questions were asked for the students to individually answer. The key questions used in the reasoning activity were created, by utilizing questions used in the previous studies. The findings revealed that the alternative conceptions of plate boundaries were classified into three levels based on established criteria. Students who attempted a variety of reasoning strategies such as causal reasoning, using an analogy, abductive reasoning, data reconstruction and concept combination, revised their alternative conception to a scientific conception after the reasoning activity. On the other hand, some students could not revise their alternative conceptions because they only conducted an incomplete reasoning strategy. The study also found that they were unable to use other reasoning strategies, either.

• Archives of Plastic Surgery
• /
• v.49 no.3
• /
• pp.413-417
• /
• 2022

The authors present a unique case of osteonecrosis of a cortical half of a fibula free flap that has not been reported in the literature yet. This complication was associated with the impairment of the vascularization of periosteum in the cortical half of fibula that was fixated with a nonlocking reconstructive 2.0-mm plate and screws but other factors could have been involved. The patient was submitted to excision of a cemento-ossifying fibroma that resulted in a left hemimaxilectomy mesoinfrastructure defect classified as the Cordeiro type 2B. The 42-year-old female patient was submitted to reconstruction with an osteomusculocutaneous fibula free flap plus a segment of fibula graft. The two bone segments of the free flap used to reconstruct the anterior and left alveolar crest were fixated with a reconstructive 2.0-mm plate of matrixMANDIBLE system. The only reported complication was an oronasal fistula that healed with conservative treatment and the referred osteonecrosis of the external cortical half of the fibula free flap with plate exposure at 2.5 years postoperatively. Surgical excision of the osteonecrosed cortical half of the fibula with the plate and screws was performed, while the other cortical underwent bone union as corroborated by computed tomography scans.

• Archives of Plastic Surgery
• /
• v.37 no.5
• /
• pp.691-694
• /
• 2010

Purpose: Central giant cell granuloma is a rare, benign giant cell tumor which commonly develops in areas near the teeth. It accounts for approximately less than 7% of benign tumors of the mandible. Clinically, central giant cell granuloma is classifed into aggressive and non-aggressive type, and usually requires surgical treatment. There has been no report of central giant cell granuloma in plastic surgery field of the country, and we report a case with a brief review of the diagnosis and treatment of the disease. Methods: A 23-year-old male presented with a hard, non-tender, growing mass with the size of $4.0{\times}3.0\;cm$ on mandible for several months. Computed tomography scan showed a solid mass within thinned outer cortex on mandible. The thinned outer cortex was excised with the mass and the inner cortex was partially removed burring. After the tumor removal, mandible was fixed by reconstruction plate. Results: Pathologic report showed numerous large multinucleated giant cells, diffusely distributed in a background of ovoid-to-spindle-shaped mononuclear cells. There was no evidence of recurrence after 1 year follow up. Bony defect was regenerated and we removed the reconstruction plate. Conclusion: Removal of central giant cell granuloma results in defect of outer cortex, which can be reconstructed by using reconstruction plate, autologous bone graft or bone cement. We used reconstruction plate as a conservative method to induce secondary healing of the outer cortical defect area, which resulted in normal mastication and occlusion with no recurrence.

• Archives of Plastic Surgery
• /
• v.37 no.4
• /
• pp.380-384
• /
• 2010

Purpose: Distinguishing different types of implants and assessing the position and size of implants by radiologic exam after orbital wall reconstruction is important in determining the surgery outcome and forecasting prognosis. We observed time-dependent density changes in three types of implants (porous polyethylene, resorbing plate and titanium mesh plate) by performing facial bone CT after orbital wall reconstructions. Methods: A total of 32 patients, who had underwent orbital wall fracture surgery from October 2006 to March 2009 and received facial bone CT as outpatients at 1 postoperative year were included in the study. Follow-up facial bone CT was performed on the patients pre- operatively, 1 month post-operatively, and 1 year post-operatively to observe the status of the orbital implants. Medpor $^{(R)}$ (Porex Surgical, Inc., Newnan, Ga.) was used as porous polyethylene and followed-up in 14 cases; for resorbing plate, Synthes mesh plate (Synthes, Oberdorf, Switzerland) was used in the reconstruction, and followed-up in 11 cases; and titanium mesh plate usage was followed-up in 7 cases. Computed tomographic scan (CT) and water's view were done for radiography, and hounsfield unit (HU) was used to compare density of those facial bone CT. Wilcoxon signed rank test was applied to statistically verify measurement difference in each group of hounsfield units. Results: Facial bone CT examination performed in 1 month post-operative showed that the density of porous polyethylene, resorbing plate and titanium mesh plate were -42.07, 105.67 and 539.48 on average, respectively. Among the three types of implants, titanium mesh plate showed the highest density due to its radiopaque feature. Following up the density of three types of implants in CT during 1 year after the orbital wall fracture surgery, the density of porous polyethylene increased in 10.52 House Field Units and the resorbing plate was decreased in 26.87 HouseField Units. There were no significant differences between densities in 1 month post-operatively and 1 year post-operatively in each group ($p{\geq}0.05$). Conclusion: We performed facial bone CT on patients with orbital fractures during follow-up period, distinguishing the types of implants by the different concentration of implant density, and the densities showed little change even at 1 year post-operative. To observe how implant densities change in facial bone CT, further studies with longer follow-up periods should be carried out.

• Archives of Plastic Surgery
• /
• v.34 no.5
• /
• pp.667-670
• /
• 2007

Purpose: Among the materials for cranioplasty, autogenous bone is ideal because it is less susceptible to infection and has lower rates of subsequent exposure. However, the procedure is technically demanding to perform and requires a donor site. Disadvantages further exist when the defect is large and there are attendant limitations in donor site. The authors present their experience with reconstruction of large skull defect using right-angled zigzag osteotomized outer table of autogenous calvarial bone, overcoming the limitation in donor site. Methods: From 2000 to 2006, 9 patients were retrospectively reviewed, who had undergone reconstruction with right angled zigzag osteotomized outer table of autogenous calvarial bone. Results: Aesthetically satisfactory skull shape was achieved. Major complications of infection, hematoma, plate exposure, and donor site complications of dural tear with bleeding, cerebrospinal fluid leak, and meningitis were not seen. One patient had delayed wound healing and was successfully managed conservatively. Conclusion: Autogenous bone is the material of choice for cranioplasty, especially in complicated cases. Right angled zigzag osteotomy is a useful method in reconstruction of large skull defects with less donor site morbidity.

• Korean Journal of Bronchoesophagology
• /
• v.2 no.1
• /
• pp.46-56
• /
• 1996

Perichondrium is generally used for reconstruction of airway and successful regeneration of cartilage framework using perichondrium are reported by several authors. It has many advantages for airway reconstruction. It can maintain the stable framework and it has higher flexibility so it's easy to design according to the shape of defects. It resist strongly against infection process. Its airtightness and rapid mucosalization enables to predict good postoperative recovery and results. To investigate the differences in cartilage regeneration between avascular and vascularized perichondrial flap, this study was designed with vascularized flaps composed of vascularized perichondrium and central auricular artery and vein. Morphologic study was performed to determine the fate of the grafted perichondrium at regular intervals using light microscopy with H & E stain. Chondrogenic potential and formation of cartilaginous plate of experimental group was superior than in the control group. Grafted perichondrium was fed by consistent feeding vessel. At 6 weeks, the regenerated cartilage could hardly be distinguished form the normal cartilage framework but in control group, regenerated cartilaginous tissue was generally immature in same period. In conclusion, this study indicated that consistent vasculature to grafed tissue is the essential factor for successful reconstruction of cartilaginous framework.

• Smart Structures and Systems
• /
• v.4 no.4
• /
• pp.449-464
• /
• 2008

An array based, outward monitoring, ultrasonic guided wave based SHM technique using a single transmitter and multiple receivers (STMR), with a small footprint is discussed here. The previous implementation of such SHM arrays used a phase-reconstruction algorithm (that is similar to the beam-steering algorithm) for the imaging of reflectors. These algorithms were found to have a limitation during the imaging of defects/reflectors that are present in the "near-field" of the array. Here, the "near-field" is defined to be approximately 3-4 times the diameter of the compact array. This limitation is caused by approximations in the beam-steering reconstruction algorithm. In this paper, a migration-based reconstruction algorithm, with dispersion correction in the frequency domain, is discussed. Simulation and experimental studies are used to demonstrate that this algorithm improves the reconstruction in the "near-field" without decreasing the ability to reconstruct defects in the "far-field" in both isotropic and anisotropic plates.