• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.6
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• pp.423-429
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• 2003

On this study. we improved the efficiency applying algorithm that is repeatedly using table of orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized 1st natural frequency of CFRP laminated composite plate without a hole and with a hole by each aspect ratio. In the case of CFRP laminated composite plate without a hole, we confirmed the reliance and efficiency of algorithm in comparison with the result of optimization achievement repeatedly using statistical table of orthogonal array of experimental design and the BFGS optimal design method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.192-195
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• 2019

Single-crystal diamond obtained by chemical vapor deposition (CVD) exhibits great potential for use in next-generation power devices. Low defect density is required for the use of such power devices in high-power operations; however, plastic deformation and lattice strain increase the dislocation density during diamond growth by CVD. Therefore, characterization of the dislocations in CVD diamond is essential to ensure the growth of high-quality diamond. In this work, we analyze the characteristics of the dislocations in CVD diamond through synchrotron white beam X-ray topography. In estimate, many threading edge dislocations and five mixed dislocations were identified over the whole surface.

• Archives of Reconstructive Microsurgery
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• v.5 no.1
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• pp.35-45
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• 1996

After transplantation of groin free flap was sucessed by the Daniel and Taylor in 1973, the reconstruction of plastic surgery was extensive and universal due to rapidly developement of anatomic study of the donor site and technique of microvascular surgery. The free tissue transfers is possible to be early activity and rehabilitation by one stage operation. It currently available allow transfer of specific tissue quality as bone, muscle, nerve to achieve a functional and cosmetic result as well as the most favorable secondary defect. But free flaps require critical, skillful technique and lengthy operating time. Also it has disadvantage of donor site morbity at the large tissue transfer. Authors were transferred with 107 cases in 103 patients from May 1987 to June 1996, and then we analysed free tissue transfer to acquire more increased sucess rate, satisfactory functional and cosmetic results. The sexual distribution was male prominent in 79 cases(76.7%), female in 24(23.3%) and age was variable distribution from 3 to 76 years old. The cause of defects was most prevalent in trauma of traffic and industrial accident in 51 cases(49%). The common recipient site were lower extremities in 47 cases(43.9%), upper extremities in 28 cases(26.5%), head and neck in 25 cases(23.4%), and trunk in 7 cases(6.5%). The type of transfer were free skin flaps in 46 cases(43%), free muscle or musculocutaneous flaps in 31 cases(29%), free vasculized or osteocutaneous flaps in 10 cases(9.3%), and specilized free flaps in 20 cases(18.7%). The anastomosis of artery was end to end anastomosis in 94 cases(87.9%), end to side anastomosis in 13 cases(12.1%) and all vein was end to end anastomosis. The number of anastomosed vessels were one artery one vein in 62 cases(57.9%), one artery two vein in 45 cases(42.1%) and vein graft was performed only one case. The postoperative mornitoring were used with temperature, color of flap, capillary refilling time, ultrasonogram, bone scan, doppler, and endoscopy. The reexploration was performed in 9 cases(8.4%), and then flap was loss in 3 cases(2.8%). Accordingly overall success rate was 97.2%. The postoperative complication was early vascular occlusion, hematoma, partial necrosis and late bulkiness, scarring, color dismatch etc. Therefore, free tissue transfer is the preferred method of treatment, even through conventional local and distant flaps are available.

• Archives of Reconstructive Microsurgery
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• v.19 no.1
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• pp.37-45
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• 2010

Purpose: First introduced by Buncke and Rose in 1979, the neurovascular partial $2^{nd}$ toe pulp free tissue transfer has been attempted to reconstruct posttraumatic finger tip injuries. Although some surgeons prefer other reconstructive methods such as skin graft and local flap, we chose the partial $2^{nd}$ toe pulp flap owing to its many advantages. We report three successful surgical cases in which the patients had undergone this particular method of reconstruction. Methods: We retrospectively examined three cases of fingertip injury patients due to mechanical injury. Bone exposure was seen in all three cases, All had undergone partial toe pulp free flap for soft tissue defect coverage. Results: All flaps survived without any complications such as partial necrosis, hematoma or dehiscence. Although tingling sensation has returned in both cases, two-point discrimination has not returned yet. Currently no patient is complaining of any pain which gradually improved during their course of recuperation. All stitches were removed on postoperative 2 weeks. Patients are satisfied with the final surgical result and there are no signs of any edema or hematoma. Conclusion: The homodigital reconstruction of finger tip injury using the partial $2^{nd}$ toe pulp flap has numerous advantages compared to other reconstructive modalities such as its resistance to wear and tear and in that it provides a non-slip palmar digital surface. However it requires microsurgery which may not be preferred by surgeons. Advanced age of the patient can be a relative contraindication to this approach since atheromatous plaque from the donor toe can compromise flap circulation after surgery. We report three successful cases which patient age was considered appropriate. Further investigation with a larger number of cases and long term follow-up is deemed necessary.

• Archives of Plastic Surgery
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• v.38 no.2
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• pp.199-202
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• 2011

Purpose: Hyoid bone is a U-shaped bone in the anterior of the neck. Hyoid bone fractures are exceedingly rare and represent only 0.002% of all fractures because of its protective position relative to the mandible and its suspension by elastic musculature. We report a patient who presented hyoid bone fracture associated with hypoglossal nerve palsy. We also discuss the possible complication and treatment. Methods: A 69-year-old man was transferred from another institution because of persistent purulent discharge from the left chin. He had a history of trauma in which a knuckle crane grabbed his face and neck in the construction site. A CT scan at the time of the accident demonstrated a comminuted fracture of the right side of the mandible and hyoid bone fracture at the junction between body and right greater cornua. The displaced fracture of hyoid bone and fullness in the pre-epiglottic space were noted, probably indicating some edema. The patient was transferred into ICU after treatment of emergency tracheostomy because the patient showed respiratory distress rapidly. When the patient was hospitalized in our emergency room, he complained of dysphagia and pain when swallowing. On examination of oral cavity, the presence of muscle wasting with fasciculation of the tongue was noted and the tongue deviates to the left side on protruding from the mouth. Pharyngolarygoscopy was performed to make sure that there was no evidence of progressive swelling and pharyngeal laceration. Results: The patient underwent surgical removal of dead and infected tissue from the wound and reconstruction of mandibular bony defect by iliac bone grafting. Hyoid bone fracture was managed conservatively with oral analgesics, soft diet and restricted movement. Hypoglossal nerve palsy was resolved within 7 weeks after trauma without complications. Conclusion: Closed hyoid bone fracture is usually uncomplicated and thus it can be treated conservatively. Surgical intervention for hyoid bone fracture is recommended for patient with airway compromise, pharyngeal perforation and painful symptoms which show no response to conservative care. Furthermore, since respiratory distress syndrome may develop quickly, close observation is required. Besides, hypoglossal nerve palsy is a rarely recognized complication of hyoid bone fracture.

• Journal of the Korean Burn Society
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• v.24 no.2
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• pp.68-73
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• 2021

Purpose: A large defect by fourth-degree burns in the upper limb requires flap reconstruction. Since severe vascular damage and decrease in blood circulation after vascular anastomosis can occur in defects caused by fourth-degree burns. Because of the disadvantages, it is difficult to apply free flap surgery to fourth-degree burns. We reconstructed a upper extremity using the pedicled Latissimus Dorsi (LD) flap in two stages. The purpose of our study is to review our experience and suggest two-staged pedicled Latissimus Dorsi (LD) flap in fourth-degree burns of upper extremities. Methods: A retrospective review was performed from 2016 to 2019, on a total of 12 fourth-degree burn patients undergone two-staged pedicled LD flap surgery as reconstruction of upper extremities in our hospital. We reviewed the location of the injury, etiology, TBSA (%), size of burns requiring flap surgery, period from 1st surgery to secondary division surgery, complications. Results: Using two-staged LD flap as a primary reconstruction, the outcome is satisfactory. This flap preserves the elbow joint and maintains the length of the forearm. We obtain low donor-site morbidity, simplicity and a small incision in the donor site. Conclusion: Using two-staged LD flap in fourth-degree burns of upper extremity is effective, such as preserving elbow joint and maintaining the length of the forearm. Successful reconstruction was achieved with excellent cosmetic results with reducing a postoperative scar, donor-site morbidity. Due to these advantages, two-staged pedicled LD flap can be an optimal option for reconstruction of fourth-degree burns in the upper limb.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.3
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• pp.207-215
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• 2009

Purpose: The aim of the present study is to evaluate the long term bone healing after horizontal ridge augmentation using auto block bone graft for implant installation timing. Materials and Methods: Five Beagle dogs(which were 14 months old and weighted approximately 10kg). In surgery 1(extraction & bone defect), premolars(P2, P3,P4) were extracted and the buccal bone plate was removed to create a horizontally defected ridge. After three months healing, in surgery 2(ridge augmentation). Auto block bone grafts from the mandibular ramus were used in filling the bone defects were fixed with stabilizing screws. The following fluorochrome labels were given intravenously to the beagle dogs: oxytetracycline 1week after the surgery, alizarin red 4 weeks after the surgery, calcein blue 8 weeks after the surgery. The tissue samples were obtained from the sacrificed dogs of 1, 4, 8, 12, 16 weeks after the surgery. Non-decalcified sections were prepared by resin embedding and microsection to find thickness of $10{\mu}m$ for the histologic examination and analysis. Results: 1. We could achieve the successful reconstruction of the horizontal bone defect by auto block bone graft. The grafted bone block remained stable morohologically after 16 weeks of the surgery. 2. In the histologic view. We observed osteoid tissue from the sample $4^{th}$ week sample and active capillary reconstruction in the grafted bone from the $12^{th}$ week sample. Healing procedures of auto bone grafts were compared to that of the host bone. 3. Bone mineralization could be detected from the $8^{th}$ week sample. 4. Fluorochrome labeling showed active bony changes and formation at the interface of the host bone and the block graft mainly. Bony activation in the grafted bone could be seen from the $4^{th}$ week samples. Conclusions: Active bone formation and remodeling between the grafted bone and host bone can be seen through the revascularization. After the perfect adhesion to host bone, Timing of successful implant installation can be detected through the ideal ridge formation by horizontal ridge augmentation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.4
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• pp.338-345
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• 1993

Mandibular discontinuity defect due to benign tumor, malignant tumor, infection, or truma results in major esthetic and biologic compromise. The primary goal of reconstruction is full restitution of function, which secondarily lead to normalization of the cosmetic deformity. The authors make a clinical study of 61 consecutive bone graft cases for mandibular reconstruction of discontinuity defect which were studied retrospectively using clinical data and radiographic findings. The cases were reviewed to evaluate the clinical success in the period from 1981 to 1990 in the Dept. of Oral & maxillofacial Surgery, Seoul National University Hospital. The criteria of the success in bone graft, are no residual infection, graft in with maintain its integrity, and remain over a half of its original size of graft in the radiographic features. The purpose of this clinical survey is to study of the mandibular discontinuity defects and success rate of free bone graft in mandibular defects. To summarize the clinical study of free bone graft, the main type of autogenous bone graft is iliac bone and corticocancellous type. Overall success rate is 80.3% in 61 followup cases over 6 months. Wire fixation and Extraoral approach has realtively better prognosis than other methods. It showed relatively poor prognosis in symphysis defects than other recipient site.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.6
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• pp.280-284
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• 2014

Purpose: This study evaluated woven silk textile for burn wound dressing materials in an animal model. Methods: Ten rats were used in this experiment. Full-thickness $2{\times}2cm$ burn wounds were created on the back of the rats under anesthesia. In the experimental group, the wounds were treated with three different dressing materials from woven silk textile. In the control group, natural healing without any dressing material was set as control. The wound surface area was measured at five days, seven days, and 14 days. Wound healing was evaluated by histologic analysis. Results: There were no statistically significant differences among groups at five days post injury. The mean defect size at seven days was largest in Group 3 ($462.87mm^2$), and smallest in Group 1 ($410.89mm^2$), not a significant difference (P=0.341). The mean defect size at 14 days was smallest at the Group 3 ($308.28mm^2$) and largest in the control group ($388.18mm^2$), not a significant difference (P=0.190). The denuded area was smaller in Group 1 ($84.57mm^2$) and Group 2 ($82.50mm^2$) compared with the control group ($195.93mm^2$), not statistically significant differences (P=0.066, 0.062). The difference between Group 3 and control was also not statistically significant (P=0.136). In histologic analysis, the experimental groups re-epithelialized more than control groups. No evidence was found of severe inflammation. Conclusion: The healing of burn wounds was faster with silk weave textile more than the control group. There was no atypical inflammation with silk dressing materials. In conclusion, silk dressing materials could be used to treat burn wounds.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.30.1-30.8
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• 2019

Background: Advancements in the field of microvascular surgery and the widespread adoption of microvascular surgical techniques have made the use of osteocutaneous fibula free flaps the standard of care in the surgical management of segmental mandibular defects. Although the literature possesses abundant evidence to support the effectiveness of fibula free flaps as a reconstructive method, there are relatively few studies reporting on outcomes as objectively measured by videofluoroscopic swallowing studies (VFSS). The purpose of this study is to explore the potential correlation between early postoperative VFSS and the long-term swallowing outcomes in patients who underwent mandibular reconstruction with fibula free flaps. Methods: We performed a retrospective chart review of 36 patients who underwent mandibular reconstruction with osteocutaneous fibular free flaps between 2009 and 2012. Demographics, clinical variables, VFSS data, and diet information were retrieved. Penetration and aspiration findings on VFSS, long-term oral feeding ability, and the need for gastrostomy tube were statistical endpoints correlated with postoperative clinical outcomes. Results: Thirty-six patients were reviewed (15 females and 21 males) with a mean age of 54 years (7-81). Seventeen cases were treated for malignancy. The size of the bony defect ranged from 3 to 15 cm (mean = 9 cm). The cutaneous paddle, a surrogate for soft tissue defect, ranged from 10 to 125 ㎠ (mean = 52 ㎠). A gastrostomy tube was present in patients preoperatively (n = 8), and postoperatively (n = 14). Seventeen patients had neoadjuvant exposure to radiation. Postoperative VFSS showed penetration in 13 cases (36%) and aspiration in seven (19%). Overall, 29 patients (80.6%) achieved unrestricted diet, and this was statistically correlated with age (p = 0.037), radiation therapy (p = 0.002), and preoperative gastrostomy tube (p = 0.03). The presence of penetration or aspiration on VFSS was a strong predictor for long-term unrestricted oral diet (p < 0.001). Conclusion: Early postoperative VFSS is an excellent predictor for long-term swallowing outcomes in patients undergoing mandibular reconstruction with osteocutaneous fibula free flaps.