• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.499-505
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• 2012

Vibratory loads imposed by the rotating blade upon the fuselage has been one of major obstacles in rotorcrafts. A new concept of rotor blade is currently developed to adopt an Active Trailing-edge Flap (ATF) to alleviate such obstacles. The flap is mounted at 65~85% spanwise location from the rotor hub. The nominal rotational speed of the blade is as high as 1,528 RPM, to match the required tip Mach number. Structural integrity is one of the important design aspects to be maintained and monitored in this special type of rotor. This is due to that many detailed components, which drive the flap, are inserted inside the rotating blade. To conduct its structural design and analysis, CAMRAD-II and the one-dimensional beam analysis are used. At the same time, three-dimensional finite element analysis are also used, such as MSC. PATRAN/NASTRAN, in order to analyze the details of the present active blade. As a result, comparable characteristics for the present rotor are predicted by both approaches.

• Archives of Plastic Surgery
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• v.50 no.3
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• pp.279-287
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• 2023

Background Hypothenar free flaps (HTFFs) have been widely used for reconstructing palmar defects. Although previous anatomical and clinical studies of HTFF have been conducted, this technique still has some limitations. In this study, we describe some tips for large flap design that allows for easy harvesting of HTFFs with minimal donor site morbidity. Methods A total of 14 HTFF for hand defect reconstruction were recorded. The oblique flap was designed in the proximal HT area following relaxed skin tension line along the axis between fourth web space and 10 mm ulnar side of pisiform. A flap pedicle includes one or two perforators with ulnar digital artery and HT branch of basilic vein. In addition, innervated HTFF can be harvested with a branch of ulnar digital nerve. Electronic medical records were reviewed to obtain data on patients' information, operative details, and follow-up period. In addition, surgical outcome score was obtained from the patient, up to 10 points, at the last follow-up. Results Mean harvest time was 46 minutes, and two perforators were included in 10 cases. The mean flap area was 10.84 cm². There were no problems such as donor site depression, scar contracture, keloids, wound dehiscence, numbness or neuroma pain at donor sites, and hypersensitivity or cold intolerance at flap site, either functionally or aesthetically. Conclusion Palmar defect reconstruction is challenging for hand surgeons. However, large HTFF can be harvested without complications using the oblique axis HTFF technique. We believe our surgical tips increase utility of HTFF for palmar defect reconstruction.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.46.1-46.7
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• 2016

Background: Osteoradionecrosis is the most dreadful complication after head and neck irradiation. Orocutaneous fistula makes patients difficult to eat food. Fibular free flap is the choice of the flap for mandibular reconstruction. Osteocutaneous flap can reconstruct both hard and soft tissues simultaneously. This study was to investigate the success rate and results of the free fibular flap for osteoradionecrosis of the mandible and which side of the flap should be harvested for better reconstruction. Methods: A total of eight consecutive patients who underwent fibula reconstruction due to jaw necrosis from March 2008 to December 2015 were included in this study. Patients were classified according to stages, primary sites, radiation dose, survival, and quality of life. Results: Five male and three female patients underwent operation. The mean age of the patients was 60.1 years old. Two male patients died of recurred disease of oral squamous cell carcinoma. The mean dose of radiation was 70.5 Gy. All fibular free flaps were survived. Five patients could eat normal diet after operation; however, three patients could eat only soft diet due to loss of teeth. Five patients reported no change of speech after operation, two reported worse speech ability, and one patient reported improved speech after operation. The ipsilateral side of the fibular flap was used when intraoral soft tissue defect with proximal side of the vascular pedicle is required. The contralateral side of the fibular flap was used when extraoral skin defect with proximal side of the vascular pedicle is required. Conclusions: Osteonecrosis of the jaw is hard to treat because of poor healing process and lack of vascularity. Free fibular flap is the choice of the surgery for jaw bone reconstruction and soft tissue fistula repair. The design and selection of the right or left fibular is dependent on the available vascular pedicle and soft tissue defect sites.

• Archives of Reconstructive Microsurgery
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• v.16 no.1
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• pp.39-47
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• 2007

With the advent of microsurgery, perforator free flap is nowadays considered the first choice for reconstruction of the extensive defect of the extremities because of their moderate thickness. Among them, anterior (anterolateral and anteromedial) thigh perforator free flaps provide the first choice for reconstruction of various soft tissue defects of the extremities with many advantage such as its large, uniform thickness, long vascular pedicle with proper vessel size and minimal donor site morbidity. But, it has still some criticism of unreliable perforators which makes us very careful in elevating the flap. Between March of 2006 and February of 2007, we treated 7 patients of soft tissue defects in the hand and lower extremities with anterior thigh perforator free flap at Hallym and DongGuk University Hospital. We performed 6 anterolateral thigh perforator free flaps based on the descending branch of lateral circumflex femoral artery (LCFA) and 1 anteromedial thigh perforator free flap based on the innominate branch of the LCFA. While approaching for the anterolateral thigh free flap, we happen to meet the cases which we should change into the anteromedial thigh free flap uneventfully on the operating field. In contrast to the original design of anterolateral thigh free flap, we had to harvest the anteromedial thigh perforator free flap in 1 case. All the anterior thigh perforator free flaps survived completely except 1 case of partial necrosis due to venous congestion. Donor sites were closed primarily and healed uneventfully within 2 weeks. Patients were satisfied with the functionally and aesthetically acceptable results. Although doppler sonography is strongly recommended preoperatively in planning the anterior thigh perforator free flaps, we should always remember the variation in vascular anatomy and be ready to change the flap choice from the anterolateral to anteromedial intraoperatively. we provide a review of the literature and present our series of anterior thigh perforator free flaps for reconstruction of the extremities.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.2
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• pp.165-170
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• 2007

During the conceptual design phase of a wing-body-canard type fighter class aircraft, as a method of maneuverability enhancement for an aircraft, effects of canard-leading edge flap scheduling have been studied. In this study, corrected supersonic panel method has been used to predict the drag polar characteristics due to canard-leading edge flap deflections in the high speed regime. Utilizing the predicted drag polar curves, the canard-leading edge flap scheduling laws have been established. These scheduling laws are the relation of canard-leading edge flap deflections and the flight conditions to maximize the lift-drag ratio. Based on the results obtained from the canard-leading edge flap scheduling, the present method has shown to be useful to enhance the maneuverability of wing-body-canard type fighter class aircraft.

• Archives of Craniofacial Surgery
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• v.21 no.1
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• pp.35-40
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• 2020

Background: Extensive eyelid defects are extremely challenging to reconstruct. Although numerous procedures for reconstructing periorbital defects have been proposed, no method is universally used. However, the Tenzel flap is the most commonly used technique to reconstruct eyelid defects affecting one-third to two-thirds of the eyelid. Methods: Recognizing the usefulness of the Tenzel method, we adapted it to reconstruct larger defects around the eyes. Seven patients underwent reconstruction with a modified Tenzel flap with an extended concept after wide excision of a malignant skin lesion. The main difference from the conventional method is that the modified Tenzel flap includes the medial portion of the lower lid defect. The design of a modified Tenzel flap begins as a semicircle at the lateral canthal area, in the same way as a classical Tenzel flap, and extends medially along the subciliary line to cover the defect on the medial lower eyelid. The follow-up time ranged from 3 to 28 months. Results: All flaps survived and healed well, with minimal scarring and natural palpebral outlines. Conclusion: Compared to traditional procedures, the modified Tenzel flap has several advantages, including a one-stage operation, a less noticeable scar, and effective prevention of complications such as lower eyelid ectropion.

• Archives of Plastic Surgery
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• v.50 no.2
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• pp.194-199
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• 2023

Moderate soft-tissue defects need stable coverage, ideally with tissue of similar characteristics and low donor site morbidity. We propose a simple technique for the coverage of moderate skin defects in the limbs. It allows intraoperative transformation of a propeller perforator flap (PPF) into a keystone design perforator flap (KDPF) in cases of unsatisfying perforator vessel or in cases of unpredictable intraoperative events. Between March 2013 and July 2019, nine patients with moderate soft-tissue defects (mean defect size 4.5 × 7.6 cm) in the limbs (two on the upper limbs and seven on the lower limbs) were covered using this technique. We performed four PPFs and five KDPFs. The mean follow-up was 5 months. There was one complication, partial distal tip necrosis in a PPF located in the leg, which healed by secondary intention within 3 weeks. The donor site was closed directly in all cases. No functional impairments were noted regardless of the perforator flap utilized. This technique enables us to employ flexible surgical strategies and allows us to make adjustments based on the patient's vascular anatomy.

• Archives of Reconstructive Microsurgery
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• v.7 no.2
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• pp.108-113
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• 1998

Reverse digital artery flaps were performed successfully to resurface the fingertip defect in 13 patients as noninnervated pattern and in 12 patients as innervated pattern from March 1993 to February 1996. No loss of flap in this series was noted. Refinements in flap design and surgical technique resulted in favourable functional and ethetic results. The average two-point discrimination of the reconstructed fingertip was 7.2mm and 4.5mm in the noninnervated and innervated flaps, respectively. This flap is an one of the ideal and reliable option for reconstruction of fingertip defects.

• Journal of Yeungnam Medical Science
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• v.11 no.2
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• pp.303-313
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• 1994

Since introduction of venous flap in 1980, many experimental studies and clinical applications of various kinds of venous flaps were reported. Venous flap has the following advantages: (1) nonbulky and goo-quality of flap (2) long & large vascular pedicle (3) easy & rapid elevation of flap (4) no sacrifice of major arteries (5) a single operarive field. But, we also have some disadvantages of difficult handling of the pliable veins and the uncertainty of flap survival. For the better result we had to design the size of the flap larger than that of defect and increase the number of draining vein to reduce the postoperative edema of the flap. We have treated the defects of soft tissue of the hand using free arterialized venous flap from the flexor aspect of the forearm & had an excellent results.

• Archives of Plastic Surgery
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• v.46 no.4
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• pp.324-329
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• 2019

Background Multiple approaches for nipple reconstruction exist, and none is considered superior to all others. The star flap is one of the most popular methods for nipple reconstruction, but gradual height loss is a major concern. We present a new modification of the star flap that incorporates a de-epithelialized dermal flap, along with the associated surgical results. Methods We reviewed the medical records of patients who underwent nipple reconstruction using the modified star flap method. The design was different from the conventional star flap in that the lateral wings were changed into a trapezoidal shape and de-epithelialized dermal flaps were added. The patients were followed up at 2, 4, 6, and 12 months postoperatively, and nipple height was measured. The postoperative nipple height achieved using the modified method was compared with that obtained using the traditional method. Results From February 2013 to June 2017, 32 patients received surgery using the modified star flap, and 18 patients who underwent nipple reconstruction before 2013 comprised the conventional method group. All patients had undergone breast reconstruction with an abdominal tissue-based flap. The mean follow-up period was 14.4 months in the modified method group and 17.3 months in the conventional method group. The mean maintenance of projection at 12 months postoperatively was $56.28%{\pm}18.58%$ in the modified method group, and $44.23%{\pm}14.15%$ in the conventional method group. This difference was statistically significant (P<0.05). Conclusions The modified method using a de-epithelialized dermal flap provides reliable maintenance of projection in patients who have undergone abdominal tissue-based breast reconstruction.