• Archives of Craniofacial Surgery
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• v.18 no.1
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• pp.50-53
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• 2017

Trichilemmal cysts are common fluid-filled growths that arise from the isthmus of the hair follicle. They can form rapidly multiplying trichilemmal tumors-, also called proliferating trichilemmal cysts, which are typically benign. Rarely, proliferating trichilemmal cysts can become cancerous. Here we report the case of a patient who experienced this series of changes. The 27-year-old male patient had been observed to have a $1{\times}1cm$ cyst 7 years ago. Eight months prior to presentation at our institution, incision and drainage was performed at his local clinic. However, the size of the mass had gradually increased. At our clinic, he presented with a $5{\times}4cm$ hard mass that had recurred on the posterior side of his neck. The tumor was removed without safety margin, and the skin defect was covered with a split-thickness skin graft. The pathologic diagnosis was a benign proliferating trichilemmal cyst. The mass recurred after 4months, at which point, a wide excision (1.3-cm safety margin) and split-thickness skin graft were performed. The biopsy revealed a trichilemmal carcinoma arising from a proliferating trichilemmal cyst. This clinical experience suggests that clinicians should consider the possibility of malignant changes when diagnosing and treating trichilemmal cysts.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.1
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• pp.130-139
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• 2016

The purpose of this paper is to analyze the problems and the sources of defective products and draw improvement plans in a small plastic boat manufacturing process using TOC (Theory Of Constraints) and statistical analysis. TOC is a methodology to present a scheme for optimization of production process by finding the CCR (Capacity Constraints Resource) in the organization or the all production process through the concentration improvement activity. In this paper, we found and reformed constraints and bottlenecks in plastic boat manufacturing process in the target company for less defect ratio and production cost by applying DBR (Drum, Buffer, Rope) scheduling. And we set the threshold values for the critical process variables using statistical analysis. The result can be summarized as follows. First, CCRs in inventory control, material mix, and oven setting were found and solutions were suggested by applying DBR method. Second, the logical thinking process was utilized to find core conflict factors and draw solutions. Third, to specify the solution plan, experiment data were statistically analyzed. Data were collected from the daily journal addressing the details of 96 products such as temperature, humidity, duration and temperature of heating process, rotation speed, duration time of cooling, and the temperature of removal process. Basic statistics and logistic regression analysis were conducted with the defection as the dependent variable. Finally, critical values for major processes were proposed based on the analysis. This paper has a practical importance in contribution to the quality level of the target company through theoretical approach, TOC, and statistical analysis. However, limited number of data might depreciate the significance of the analysis and therefore it will be interesting further research direction to specify the significant manufacturing conditions across different products and processes.

• Archives of Craniofacial Surgery
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• v.19 no.1
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• pp.20-34
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• 2018

Background: Polydeoxyribonucleotide (PDRN) influencing cellular growth and differentiation is recognized to promote wound healing by stimulating tissue repair. Although PDRN can be extracted from human placentas, PDRN medications have recently been extracted from the semen of trout (Oncorhynchus mykiss) and salmon (Oncorhynchus keta). The present study was designed to evaluate the wound healing effects of O. keta-derived PDRN for injection (Rejuvenex) and PDRN cream (Rejuvenex Cream) in comparison with those of O. mykiss-derived PDRN injection (Placentex). Methods: Full-thickness skin defects were made on the back of mice (n=60). The mice were divided into the following four groups according to the dressing used for the wounds: O. mykiss-derived PDRN injection group, O. keta-derived PDRN injection group, O. ketaderived PDRN cream group, and normal saline soaked dressing group (control group). We analyzed the gross findings, wound sizes, histological findings, immunohistochemistry and enzyme-linked immunosorbent assays for the groups immediately after the treatment, and again after 4, 7, and 10 days of treatment. Results: The wound healing effects were the greatest in the O. keta-derived PDRN injection and O. mykiss-derived PDRN injection groups, which showed similar scores, followed by the O. keta-derived cream and normal saline soaked dressing groups. Conclusion: The injection of PDRN extracted from O. keta was found to be as effective at healing full-thickness skin defects as the O. mykiss-derived PDRN injection, which is currently used in the clinic. Moreover, the O. keta-derived PDRN injection was also found to reduce the time required for wound healing.

• Composites Research
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• v.16 no.2
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• pp.26-32
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• 2003

Optical fibers, for splice, are stripped of their plastic coatings with a plastic stripper and cut off at the end. Therefore, stripped fibers often receive accidental damages and sustain small flaws or cracks. As a result, the breaking strength of a fiber splice made under normal conditions is reduced to about 0.4∼1 ㎏ on the average, nearly one-tenth of the fiber's strength. This makes it necessary to reinforce the splice. One of the most practical and reliable methods for optical fiber splicing is fusion splicing, comprising the steps of tripping the plastic coatings from the two fiber ends to be splice, placing the two bare fiber ends in an end-to-end position, and of fusion splicing, such as are fusion. Generally, steel bar (SB) sleeve is used to reinforce this fusion-splicing region. However, this type of sleeve has a critical defect to keep optical lose after bent by a sudden load. New type of composite spring (CS) sleeve is developed to make up for the weak points in the SB sleeve. This sleeve has an effect on restoration to the original state after eliminating the bending load. The optical spectrum analyzes results show the availability of reinforcement for the fusion splicing optical fiber using small diameter composite springs under the various loading conditions.

• Archives of Reconstructive Microsurgery
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• v.8 no.2
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• pp.130-138
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• 1999

The lower extremity injuries are extremely increasing with the development of industrial & transportational technology. For the lower extremity injuries that result from high-energy forces, particularly those in which soft tissue and large segments of bone have been destroyed and there is some degree of vascular compromise, the problems in reconstruction are major and more complex. In such cases local muscle coverage is probably unsuccessful, because adjacent muscles are destroyed much more than one can initially expect. Reconstruction of the lower extremity has been planned by dividing the lower leg into three parts traditionally The flaps available in each of the three parts are gastrocnemius flap for proximal one third, soleus flap for middle one third and free flap transfer for lower one third. Microvascular surgery can provide the necessary soft tissue coverage from the remote donnor area by free flap transfer into the defect. Correct selection of the appropriate recipient vessels is difficult and remains the most important factor in successful free flap transfer. Vascular anastomosis to recipient vessels distal to the zone of injury has been advocated and retrograde flow flaps are well established in island flaps. Retrograde flow anastomosis could not interrupt the major blood vessels which were essential for survival of the distal limb, the compromise of fracture or wound healing might be prevented. During 5 years, from March 1993 to Feb. 1998, we have done 68 free flap transfers in 61 patients to reconstruct the lower extremity. From analysis of the cases, we concluded that for the reconstruction of the lower extremity, free flap transfer yields a more esthetic and functional results.

• Archives of Reconstructive Microsurgery
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• v.17 no.2
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• pp.87-93
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• 2008

Purpose: Because of good blood supply of the pedicled perforator flap and its advantage of not requiring vessel anastomosis compared to pedicled flap, it is widely used recently. The authors intended to report the results of various pedicled perforator flaps which have been performed to reconstruct the soft tissue defects and the utility of the flap. Methods: The study was conducted for 12 cases of pedicled perforator flap which were performed at the plastic surgery department of the current hospital from the period of June, 2005 to August, 2008. Four patients were male and eight patients were female and their age was ranged from 22 to 74 years old with mean age of 42.6 years old. The sites were 1 case on face, 3 cases on chest, 3 cases on back, 4 cases on coccyx, and 1 case on foot. Results: The defect sites of all patients were successfully reconstructed by using the pedicled perforator flap. Although most of the flaps revealed congestion at the early stage after the surgery, they were recuperated within few days. One case of skin flap was reported to be partially necrotized in old age woman who has no reliable perforator. Other than that, all defects were covered successfully and acceptable aethetically. Conclusion: As stated in above, the pedicled perforator flap has many useful advantages than the conventional pedicled flap and various free flap. Unless free flap must be required, the use of pedicled perforator flap is recommended by first choice for soft tissue coverage.

• Archives of Reconstructive Microsurgery
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• v.22 no.1
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• pp.33-37
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• 2013

Purpose: The concept and development of perforator free flaps have led to significant advances in microsurgery. Ongoing developments in perforator free flap surgery are aimed at reducing complications and improving surgical outcomes. The aim of this study was to evaluate the effectiveness and application of supermicrosurgery in free flap surgery. Materials and Methods: A total of 267 patients with soft tissue defects of the lower extremity due to various etiologies from January, 2007 to January, 2013. The patients received either an anterolateral thigh free flap (n=83), a superficial circumflex iliac artery free flap (n=152), an upper medial thigh free flap (n=19), or a superior gluteal artery perforator free flap (n=13). Microanastomosis was performed using a perforator-to-perforator technique, either end-to-end or end-to-side. Results: The mean postoperative follow up period was eight months (range: one to 16 months) and flap loss occurred in 11 cases out of 267. All cases of flap loss occurred within two weeks of surgery due to either arterial insufficiency (n=5) or venous congestion (n=6). Conclusion: Supermicrosurgery enables the selection of the most efficient perforator for microanastomosis at the defect site. It also reduces the time required for dissection of recipient vessels, and reduces the possibility of injury to major vessels. Microsurgery using a vessel of less than 1 mm has been reported to increase the risk of flap failure; however, using the most advanced surgical tools and developing experience in the technique can produce success rates similar to those found in the literature.

• Archives of Reconstructive Microsurgery
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• v.14 no.2
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• pp.105-111
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• 2005

Perforator flaps have become increasingly popular in microsurgery nowadays and are being used widely for many cases of reconstruction after trauma and cancer ablation. And thoracodorsal perforator based free flap is one of them having the merits of carrying a large skin paddle with leaving intact innervation and function of the remaining latissimus dorsi muscle. We made a homogeneous thin flap excluding the main muscle with a long vascular pedicle and tried to decrease the donor site morbidity. But, it needs a long learning-curve and we have met marginal flap necrosis frequently. Besides, prolonged operation time for complete perforator dissection may be a tedious job to the microsurgeon. To overcome these disadvantages, we usually included very small portion of the latissimus dorsi muscle during this flap elevation around the pedicled 2-3 thoracodorsal perforators during this flap elevation. We performed 3 cases of thoracodorsal perforator based free flap at Hallym university sacred heart hospital between May and August 2005 for the soft tissue defect of the scalp and feet. The average flap size was $8{\times}14\;cm$. Although it is not a true perforator flap, we can get the reliability for the flap survival with much better blood circulation and save the time of one or two hours to dissect the perforators completely. All cutaneous flaps survived completely without any complication except one fatty female who had the very small superficial fat necrosis due to flap bulkiness. We believe the thoracodorsal perforator based free flap can be extended its versatility and reliability by including the very small portion of the muscle around the perforators.

• Archives of Reconstructive Microsurgery
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• v.19 no.2
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• pp.108-111
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• 2010

Purpose: In reconstructing a defect on the dorsum of the hand, there are many cases of extensor tendons exposed or even missing. The repaired or reconstructed tendons need relevant gliding environment for good functional recovery. The anterolateral thigh flap offers a vascular fascial component with large amounts that can be used for covering exposed tendons and we report a unique case of single-stage hand dorsum and gliding surface reconstruction. Methods: A 35-year-old man had severe post-traumatic scarring in his left dorsal hand and coverage of the flap with split-thickness skin graft has been done before. After scarred skin excision and extensor tendon graft for missed part, a free anterolateral thigh adipofascial flap was used to resurface the hand dorsum and to reconstruct a two-layer gliding surface of the extensor tendons. The extensor tendons were wrapped in the fascial component with the fat layer inside. Results: He had an uneventful postoperative course without infection, dehiscence and flap necrosis. Good overall functional recovery and tendon excursion were observed. He was also satisfied with postoperative appearance. Conclusion: A free anterolateral thigh adipofascial flap was used successfully for reconstruction of a two-layer tendon gliding surface to treat a patient with severe scarring in the dorsal hand.

• Archives of Craniofacial Surgery
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• v.12 no.1
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• pp.48-52
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• 2011

Purpose: Many advances have been made in lower eyelid reconstruction surgical procedures after tumor ablative therapy. These include skin grafts, local flaps, free flaps, and skin expansion. When a full-thickness defect of the lower eyelid is reconstructed with many free flaps, ectropion and deformity of the medial and lateral canthal areas are common late complications caused by gravitational descent. The radial forearm free flap is widely used because of its lack of bulk, ease of dissection, malleability, and hairlessness. This report introduces a novel method for preventing ectropion using a composite radial forearm free flap reconstruction and palmaris longus suspension technique. Methods: A 70-year-old man had a malignant melanoma on his left lower eyelid. The patient was referred to our department after a biopsy confirmed the initial diagnosis. A full-thickness wide resection with a 25 mm free margin was performed, and a $5{\times}8cm$ radial forearm flap was elevated with a vascularised palmaris longus tendon. The palmaris longus tendon was fixed to the medial and lateral orbital rim perisoteum and the deep temporal fascia. The buccal mucosa was grafted to reconstruct the inner conjunctival layer. The pedicle vessels were anastomosed to the left superficial temporal artery and vein. Results: The postoperative clinical course was uneventful. The flap showed good texture and color match. No ectropion was noted 14 months after surgery and the tumor did not recur. The patient was quite satisfied with the final outcomes. Conclusion: Use of a radial forearm free flap and the palmaris longus tendon is an effective method for a full-thickness lower eyelid reconstruction.