• Journal of Korean Neurosurgical Society
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• 제30권11호
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• pp.1284-1290
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• 2001

Objective : PCB cervical instrument is a newly introduced fusion device which comprises cervical plate, cage (spacer) and screw system. It is developed to enhance fusion rate and stability, as well as to reduce complications related to hardware failure. We investigated the efficacy of clinical and radiological results of PCB instrument and Lubboc bone. Methods : From August, 1998 to October, 1999, authors performed 54 cases of anterior cervical interbody fusion with PCB instrument and Lubboc bone. Retrospective analysis was undertaken based on clinical and radiological findings. Clinical improvement was evaluated according to Odom's criteria. Cervical plain films and tomography were taken every 2 months to evaluate the degree of interbody fusion and disc height changes. Results : Bone fusion was observed in 36 cases(90%) over 6 months after operation, and during which time there was no significant interval change. There were 3 cases of hardware dislodgement. Disc height was increased significantly and preserved in all cases. Clinical outcome over good degree was seen more than 94% of patients. Conclusion : Longer follow-up period and comparative studies to similar instrument appear to be necessary, but this instrumentation system has shown high fusion rate and fewer adverse effects in our series. We believe this system might be indicated for the treatment of cervical trauma and degenerative disease in selective cases.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권5호
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• pp.343-350
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• 2017

The aim of this study is to introduce a surgical technique that can maintain blood supply to prevent condylar resorption in the extracorporeal reduction of condylar fracture. Neither the medial pterygoid muscle on the ramal bone nor the lateral pterygoid muscle on the condylar fragment was detached after vertical ramal osteotomy. Thus, reduction was performed in the intracorporeal state. Therefore, blood supply was expected to be maintained to the fragments of both the condylar and ramal bones. On postoperative radiographs, the anatomical outline of the fractured condyle was well restored, and the occlusion was stable. In the unilateral case, there were no signs of mandibular condylar resorption until postoperative 3 weeks. In the 2 bilateral cases, condylar displacements with plate fractures and screw loosening were observed at postoperative 1 month or 5 months, but radiodensity at the displaced fracture site increased during the follow-up period. Finally, complete remodeling of the condylar fragments with restored anatomic appearance was observed on 8-month or 2-year follow-up radiographs. All cases exhibited good healing aspects with no signs or symptoms of mandibular condylar dysfunction during the postoperative remodeling period after intracorporeal reduction of condylar fracture.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제39권3호
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• pp.285-291
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• 2015

A centrifuge works on the principle that particles with different densities will separate at a rate proportional to the centrifugal force during high-speed rotation. Dense particles are quickly precipitated, and particles with relatively smaller densities are precipitated more slowly. A decanter-type centrifuge is used to remove, concentrate, and dehydrate sludge in a water treatment process. This is a core technology for measuring the sludge conveyance efficiency improvement. In this study, a smoothed particle hydro-dynamic analysis was performed for a decanter centrifuge used to convey sludge to evaluate the efficiency improvement. This analysis was applied to both the original centrifugal model and the design change model, which was a ball-plate rail model, to evaluate the sludge transfer efficiency.

• Archives of Plastic Surgery
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• 제37권2호
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• pp.195-198
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• 2010

Purpose: The zygoma is a key element which composes the facial contour. Zygomatic fracture induces facial asymmetry. We use radiologic evaluation or inspections mainly for identification of symmetry after reduction depressed zygomatic fracture. But the disadvantages of such methods are time-consuming and complicated process. So we tried to develop a new testing method with a ruler and a level. Methods: In unilateral depressed zygomatic fracture patient, parallel to the patient's head to make sure lay horizontaly. Put the leg of a ruler on the malar eminence so that it is at the same distance from the facial midline. Then take the level of malar eminence as put the level above the ruler. This process was performed before and after the reduction. Results: We were able to fix with plate and screw after checking the results of reduction fast and easily. Good results were obtained at post-operative radiologic evaluation. Conclusion: We can easily get the ruler and level around life. This method is not only simple but also shorttime process compared with other method-radiologic evaluation or inspection. And the operator can explain the results to the patients easily and objectively. Authors obtained the good results with this new method, and would introduce it for another method of identifying the result of reduction in depressed zygomatic fractures.

• Journal of Korean Foot and Ankle Society
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• 제13권2호
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• pp.142-145
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• 2009

Purpose: The aim of this study was to retrospectively evaluate the clinical and radiological results of the first metatarsophalangeal joint arthrodesis with two crossed screws fixation. Materials and Methods: We treated 23 patients (24 cases) with arthrodesis of the first metatarsophalangeal joint using two crossed screws fixation between December 2000 and May 2005. There were 3 male patients and 20 female patients. Ages ranged from 28 to 74 years (mean, 50 years). Follow-up ranged from 4.1 to 8.2 years (mean, 6.5 years). The American Orthopaedic Foot and Ankle Society (AOFAS) score and their satisfaction was evaluated clinically, foot anteroposterior and lateral radiograph, radiologically. Results: Of the 24 cases, 6 had surgery for dorsal plate and screws fixation because of failure to acquire firm fixation with two crossed screws fixation. All 6 cases acquired bony union. Fusion of the hallux first metatarsophalangeal joint occurred in 16/18 cases (89%). Nonunion occurred in 2 cases (11%) and was asymptomatic. At last follow-up, hallux valgus angle ranged from 11 to 25 degrees(mean, 17.7 degrees), dorsiflexion ranged from 15 to 25 degrees (mean, 22 degrees).The mean preoperative AOFAS score of 37 points(range, 28 to 45 points) improved to a mean of 77 points (range, 65~90 points) postoperatively. The result of the procedure as rated subjectively by the patient was excellent for 5 cases, good for 11 cases and fair for 2. Conclusion: Comparatively, the arthrodesis of the first metatarsophalangeal joint with crossed screws fixation showed a satisfactory clinical results, we thought that require technical attention for firm fixation in operation.

• Journal of Korean Neurosurgical Society
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• 제29권8호
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• pp.1055-1062
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• 2000

Objectives : Burst fracture of the lower lumbar spine(L3-L5) is rare and has some different features compare to that of thoracolumbar junction. Lower lumbar spine is flexible segments located deeply, and has physiologic lordosis. All of these contribute to making surgical approach difficult. Generally, lower lumbar burst fracture is managed either anteriorly or posteriorly with various fixation and fusion methods. But there is no general guideline or consensus regarding the proper approach for such lesion. We have tried to find out the influencing factors for selecting the surgical approach through the analysis of lower lumbar burst fractures treated for last 4 years(1994.3-1998.3). Method : This study includes 15 patients(male : 10, female : 5, age range 20-59 years with mean age of 36.7 years, L3 : 8 cases, L4 : 5 cases, L5 : 2 cases). Patients were classified into anterior(AO) and posterior operated(PO) groups. We investigated clinical findings, injured column, operation methods, and changes in follow-up radiologic study (kyphotic angle) to determine the considerable factors in selecting the surgical approaches. Results : There were 5 AO and 10 PO patients. Anterior operation were performed with AIF with Kaneda or Z-plate and posterior operation were done with pedicle screw fixation with PLIF with cages or posterolateral fusion. Canal compression was 46.6% in AO and 38.8% in PO. The degree of kyphotic angle correction were 10.7 degree(AO) and 8.5 degree(PO), respectively. There was no statistical difference between anterior and posterior operation group. All patients showed good surgical outcome without complications. Conclusion : Anterior operation provided good in kyphotic angle correction and firm anterior strut graft, but it difficulty arose in accessing the lesions below L4 vertebra. While posterior approach showed less correction of kyphotic angle, it required less time and provided better results for accompanied adjacent lesion and pathology such as epidural hematoma. The level of injury, canal compression, biomechanics, multiplicity, and pathology are considered to be important factors in selection of the surgical approach.

• Archives of Craniofacial Surgery
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• 제10권1호
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• pp.33-36
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• 2009

Purpose: Fractures of the mandibular condylar area are common injuries that account for 29% to 40% of fractures of the facial bones and represent 20% to 62% of all mandibular fractures. Currently 3 main methods are being used in the treatment of mandibular subcondylar fractures: closed reduction; open reduction and internal fixation; Endoscopic reduction and internal fixation. Each method has its proponents and opponent as well as advantages and disadvantages, and indications for each vary among surgeons. There are six approaches of open reduction: submandibular, retromandibular, preaurilcular, postauricular, intraoral, transparotid approach. Among them, transparotid approach has been described for subcondylar exposure with dissection in the direction of facial nerve fibers to expose the bone through the parotid gland. This approach carries the risk of a parotid glandular fistula as well as facial nerve injury but has the advantage of being directly over the fracture site. We report safety and efficacy of surgical treatment using a transparotid approach for direct plating. Methods: A 43-year-old man sustained multiple facial bone fractures by driver traffic accident. Mandibular subcondyle was fractured and dislocated internally. We performed open reduction and internal fixation by transparotid approach. Fractured site was fixed by titanium mini plate & screw. We applicated arch bar for approximately 3 weeks. Results: Follow-up length was about 5months. Scar of surgical incision was indistinct, there was no symptoms and signs of facial nerve and parotid gland injury, and maximal mouth opening was measured 49.5 mm. Conclusion: Transparotid approach has high risks of facial nerve and parotid gland injury, but paradoxically it is the most effective technique in saving facial nerve. Open reduction and internal fixation of mandibular subcondylar fracture by transparotid approach with precise and versed procedure, best outcome can be expected.

• The korean journal of orthodontics
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• 제50권5호
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• pp.346-355
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• 2020

The treatment of skeletal Class III malocclusion in adolescents is challenging. Maxillary protraction, particularly that using bone anchorage, has been proven to be an effective method for the stimulation of maxillary growth. However, the conventional procedure, which involves the surgical implantation of mini-plates, is traumatic and associated with a high risk. Three-dimensional (3D) digital technology offers the possibility of individualized treatment. Customized mini-plates can be designed according to the shape of the maxillary surface and the positions of the roots on cone-beam computed tomography scans; this reduces both the surgical risk and patient trauma. Here we report a case involving a 12-year-old adolescent girl with skeletal Class III malocclusion and midface deficiency that was treated in two phases. In phase 1, rapid maxillary expansion and protraction were performed using 3D-printed mini-plates for anchorage. The mini-plates exhibited better adaptation to the bone contour, and titanium screw implantation was safer because of the customized design. The orthopedic force applied to each mini-plate was approximately 400-500 g, and the plates remained stable during the maxillary protraction process, which exhibited efficacious orthopedic effects and significantly improved the facial profile and esthetics. In phase 2, fixed appliances were used for alignment and leveling of the maxillary and mandibular dentitions. The complete two-phase treatment lasted for 24 months. After 48 months of retention, the treatment outcomes remained stable.

• Archives of Craniofacial Surgery
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• 제17권4호
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• pp.211-217
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• 2016

Background: Nonsyndromic craniosynostosis is a relatively common craniofacial anomaly and various techniques were introduced to achieve its operative goals. Authors found that by using smaller bone fragments than that used in conventional cranioplasty, sufficiently rigid bone union and effective regeneration capacity could be achieved with better postoperative outcome, only if their stable fixation was ensured. Methods: Through bicoronal incisional approach, involved synostotic cranial bone together with its surrounding areas were removed. The resected bone flap was split into as many pieces as possible. The extent of this 'multi-split osteotomy' depends on the degree of dysmorphology, expectative volume increment after surgery and probable dead space caused by bony gap between bone segments. Rigid interosseous fixation was performed with variable types of absorbable plate and screw. In all cases, the pre-operational three-dimensional computed tomography (3D CT) was checked and brain CT was taken immediately after the surgery. Also about 12 months after the operation, 3D CT was checked again to see postoperative morphology improvement, bone union, regeneration and intracranial volume change. Results: The bony gaps seen in the immediate postoperative brain CT were all improved as seen in the 3D CT after 12 months from the surgery. No small bone fragment resorption was observed. Brain volume increase was found to be made gradually, leaving no case of remaining epidural dead space. Conclusion: We conclude that it is meaningful in presenting a new possibility to be applied to not only nonsyndromic craniosynostosis but also other reconstructive cranial vault surgeries.

• Archives of Reconstructive Microsurgery
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• 제16권2호
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• pp.125-132
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• 2007

Introduction: Ulna is nearly equal to radius in function and bony architecture and strength in forearm. But in lower extremity, fibula is 1/5 of tibia in anatomic and functional point so we can find fibula transposition is commonly used in defect of tibia. We cannot find other article about segmental forearm bone transposition in man. The purpose of this study was to report our clinical and functional result of undergoing segmented transposition of ipsilateral ulna with its own vascular supply in defect of radius in 6 cases. Material and method: From June 1994 to October 2007, 7 segmented bone transpositional grafts in forearm were performed in Kyung Hee Medical Center. The distribution of age was from 20 years old to 73 years old. There was male in 6 cases and female in 1 case. The causes of operation were giant cell tumor in 1 case and traumatic origin in 6 cases; it was nonunion in 2 cases and fracture with severe comminution in 4 cases. Ipsilaterally segmented ulna keeping its own vascular supply was transported to defect of radius in severe traumatic patients and one patient whose tumor in radius had been excised. Transported ulna was fixed to proximal and distal radius remnants by plate and screw. In one case with giant cell tumor, transported ulna was connected to radius across wrist joint as wrist joint fusion. Joint preserving procedures were performed in 6 cases with crushing injury of radius. Results: We could obtain solid bony union in all cases and good functional results. The disadvantage was relative shortening of forearm, but we could overcome this problem. Conclusion: We think that ipsilateral segmented ulna transposition keeping its own vascular supply to radius can be perfomed with one of procedures in cases with wide defect in radius.