• 동력기계공학회지
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• 제18권6호
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• pp.166-173
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• 2014

In this study, a laminated composite material with dispersing aluminum oxide powder between the CFRP laminate plies, and also CFRP composites without aluminium oxide powder were fabricated for Mode I experiments using the DCB specimen and a tensile test. The behavior of the crack and the change of the interfacial fracture toughness were evaluated. Also in order to evaluate the damage mechanism for the crack extension, the AE sensor on the surface of the DCB test specimen was attached. AE amplitude was estimated for CFRP-alumina and CFRP composite. And the fracture toughness was evaluated by the stress intensity factor and energy release rate. The results showed that an unstable crack was propagated rapidly in CFRP composite specimen along with the interface, but crack propagation in CFRP-alumina specimen was relatively stable. From results, we show that aluminium oxide powder spreaded uniformly in the interface of the CFRP laminate carried out the role for preventing the sudden crack growth.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제48권3호
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• pp.182-187
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• 2022

Superolateral dislocation of the condyle is a rare mandibular fracture. The treatment goal is to return the dislocated condyle to its original position to recover normal function. This study reports on superolateral dislocation of the condyle with mandibular body fracture. The mandibular body was completely separated, and the medial pole of the condyle head was fractured. The condyle segment was unstable and easily dislocated after reduction. The temporalis muscle on the condyle segment might have affected the dislocation of the condyle. A coronoidectomy was performed to disrupt the function of the temporalis muscle on the condyle segment in order to successfully reduce the dislocated condyle. Coronoidectomy is a simple procedure with minimal complications. We successfully performed a coronoidectomy to reduce the superolateral displaced condyle to its original position to achieve normal function. Coronoidectomy can be effectively used for reduction of superolaterally displaced condyles combined with severe maxilla-mandibular fractures.

• Journal of Korean Neurosurgical Society
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• 제59권2호
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• pp.122-128
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• 2016

Objective : To illustrate the technique of single-stage posterior subtotal corpectomy and circumferential reconstruction for the treatment of unstable thoracolumbar burst fractures and to evaluate the radiographical and clinical outcomes of patients treated using this technique. Methods : 16 consecutive patients with unstable thoracolumbar burst fractures were treated with single-stage posterior subtotal corpectomy and circumferential reconstruction. The mean patient age was 54.8 years. The mean follower up period was 25 months. Five patients suffered from T12 fractures, 10 from L1, 1 from L2. The segmental kyphosis, neurologic status, visual analogue scale for back pain was evaluated before surgery and at follow up. Results : The segmental kyphotic angle improved from 18.5 degrees before surgery to -9.2 degrees at the last follow up. The mean correction angle was 28.9 degrees. The mean surgical time was 255 minutes, and a mean intraoperative blood loss was 1073 mL. Intraoperative complications included two dural tears, and a superficial wound infection. There were no other severe complications. The mean visual analog scale of back pain decreased from a mean value of 6.6 to 2 at the last follow up. Conclusion : The single-stage posterior subtotal corpectomy and circumferential reconstruction achieved satisfactory kyphosis correction with direct visualization of the circumferentially decompressed spinal cord, as well as good fusion with less blood loss and complications. It is a safe and reliable surgical treatment option for unstable thoracolumbar burst fractures.

• Journal of Korean Neurosurgical Society
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• 제40권4호
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• pp.249-255
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• 2006

Objective : This study is to evaluate the efficacy of dorsal short-segment fixation in unstable thoracolumbar junction fractures. Methods : The cases of 20 patients who underwent dorsal short-segment fixation were reviewed retrospectively. Clinical outcomes were analysed using Sonntag's pain level, work status, and neurological scale according to the modified Frankel classification. Radiological outcomes were analysed using Mumford's anterior body compression[%], canal compromise ratio, and Cobb's kyphotic angle. Results : At the latest clinical follow-up [average=14.6 months]. there were 19 [95.0%] in group I and 1 patient [5.0%] in II in pain level. The postoperative work status were 17 [85.0%] in group I, 2 patients [10.0%] in II, and 1 patient [5.0%] in V. Surgery brought to improve the neurologic status. In success group [19 cases, 95%], the average canal compromise ratio was reduced from 0.57 [${\pm}0.07$] to 0.05 [${\pm}0.08$] [P<005], the average anterior body compression [%] was reduced from 41% [${\pm}17$] to 18% [${\pm}14$] [P<0.05], and the average preoperative kyphotic angle was $20.0^{\circ}$ [${\pm}9.0$], and corrected to $5.7^{\circ}$ [${\pm}7.1$] postoperatively, and progressed to $7.8^{\circ}$ [${\pm}6.2$] at the latest follow-up. There was a case of implantation failure in an elderly osteoporotic patient. Conclusion : Although there are limitations in the patient number and follow-up period, the present study favors dorsal short-segment fixation for selective cases in unstable thoracolumbar junction fractures.

• Clinics in Shoulder and Elbow
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• 제22권1호
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• pp.29-36
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• 2019

Background: The execution of fibular allograft augmentation in unstable proximal humerus fractures (PHFs) was technically demanding. In this study, the authors evaluated the clinical and radiographic outcomes after tricortical iliac allograft (TIA) augmentation in PHFs. Methods: We retrospectively assessed 38 PHF patients treated with locking-plate fixation and TIA augmentation. Insertion of a TIA was indicated when an unstable PHF showed a large cavitary defect and poor medial column support after open reduction, regardless of the presence of medial cortical comminution in preoperative images. Radiographic imaging parameters (humeral head height, HHH; humeral neck-shaft angle, HNSA; head mediolateral offset, HMLO; and status of the union), Constant score, and range of motion were evaluated. Patients were grouped according to whether the medial column support after open reduction was poor or not (groups A and B, respectively); clinical outcomes were compared for all parameters. Results: All fractures healed radiologically (average duration to complete union, 5.8 months). At final evaluation, the average Constant score was 73 points and the mean active forward flexion was $148^{\circ}$. Based on the Paavolainen assessment method, 33 patients had good results and 5 patients showed fair results. The mean loss of reduction was 1.32 mm in HHH and 5.02% in HMLO. None of the parameters evaluated showed a statistically significant difference between the two groups (poor and not poor medial column support). Conclusions: In unstable PHFs, TIA augmentation can provide good clinical and radiological results when there are poor medial column support and a large cavitary defect after open reduction.

• Composites Research
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• 제16권4호
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• pp.44-50
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• 2003

균열선단에 발생하는 손상역은 재료의 파괴인성 메카니즘을 알 수 있게 하는 중요한 영역이다. 본 연구에서는 고무변성 에폭시 수지의 균열선단 손상역의 생성 및 성장 과정을 음향방출법을 이용하여 조사하였다. 고무변성 에폭시 수지의 고무함량은 5 wt%와 15 wt%로 하였고, 3점 굽힘시험편을 사용하여 모드 I 파괴시험에 대한 각 시험편의 파괴인성값을 구하였다. 또한, 균열선단의 손상역과 그 내부의 고무입자 변형상태를 편광현미경과 원자력간 현미경을 사용하여 관찰하였다. 고무변성 에폭시 수지의 균열선단부의 손상역은 파괴하중의 약 13 % 하중에서 생성이 되어, 약 57 % 하중까지 균열개시 없이 성장하였다. 57 % 하중 근처에서 개시만 균열은 최대하중부근까지 고착-활강거동을 반복하면서 안정 / 불안정 파괴로 진전하였다 이 과정에서 발생한 음향방출신호의 시간-주파수 분석결과, 고투입자 내부에서의 케비테이션 생성단계에서 주파수대역은 0.15 ∼ 0.20 MHz 이었고, 그 후의 안정 및 불안정시의 주파수 대역은 0.20∼0.30MHz 이었다.

• Journal of Welding and Joining
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• 제33권1호
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• pp.35-40
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• 2015

Recently, there have been the increase of ship size and the development of oil and gas in arctic region. These trends have led to the requirements such as high strength, good toughness at low temperature and good weldability for prevent of brittle fracture at service temperature. There has been the key issue of crack arrestability in large size structure such as container ship. In this report for the first time, crack arrest toughness of thick steel plate welds was evaluated by large scale ESSO test for estimate of brittle crack arrestability in thick steel plate. For large structures using thick steel plates, fracture toughness of welded joint is an important factor to obtain structural integrity. In general, there are two kinds of design concepts based on fracture toughness: crack initiation and crack arrest. So far, when steel structures such as buildings, bridges and ships were manufactured using thick steel plates (max. 80~100mm in thickness), they had to be designed in order to avoid crack initiation, especially in welded joint. However, crack arrest design has been considered as a second line of defense and applied to limited industries like pipelines and nuclear power plants. Although welded joint is the weakest part to brittle fracture, there are few results to investigate crack arrest toughness of welded joint. In this study, brittle crack arrest designs were developed for hatch side coaming of large container ships using arrest weld, hole, and insert technology.

• Journal of Trauma and Injury
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• 제36권4호
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• pp.362-368
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• 2023

Purpose: Clinical reports on treatment outcomes of sternal fractures are lacking. This study details the clinical features, treatment approaches, and outcomes related to traumatic sternal fractures over a 10-year period at a single institution. Methods: A retrospective cohort study was conducted of patients admitted to a regional trauma center between January 2012 and December 2021. Among 7,918 patients with chest injuries, 266 were diagnosed with traumatic sternal fractures. Patient data were collected, including demographics, injury mechanisms, severity, associated injuries, sternal fracture characteristics, hospital stay duration, mortality, respiratory complications, and surgical details. Surgical indications encompassed emergency cases involving intrathoracic injuries, unstable fractures, severe dislocations, flail chest, malunion, and persistent high-grade pain. Results: Of 266 patients with traumatic sternal fractures, 260 were included; 98 underwent surgical treatment for sternal fractures, while 162 were managed conservatively. Surgical indications ranged from intrathoracic organ or blood vessel injuries necessitating thoracotomy to unstable fractures with severe dislocations. Factors influencing surgical treatment included flail motion and rib fracture. The median length of intensive care unit stay was 5.4 days (interquartile range [IQR], 1.5-18.0 days) for the nonsurgery group and 8.6 days (IQR, 3.3-23.6 days) for the surgery group. The median length of hospital stay was 20.9 days (IQR, 9.3-48.3 days) for the nonsurgery group and 27.5 days (IQR, 17.0 to 58.0 days) for the surgery group. The between-group differences were not statistically significant. Surgical interventions were successful, with stable bone union and minimal complications. Flail motion in the presence of rib fracture was a crucial consideration for surgical intervention. Conclusions: Surgical treatment recommendations for sternal fractures vary based on flail chest presence, displacement degree, and rib fracture. Surgery is recommended for patients with offset-type sternal fractures with rib and segmental sternal fractures. Surgical intervention led to stable bone union and minimal complications.

• 대한정형외과학회지
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• 제52권1호
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• pp.25-32
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• 2017

목적: 고령 환자에서 발생한 불안정성 대퇴골 전자간부 골절의 치료 시 골수강내 금속정의 길이에 따른 방사선적, 임상적 치료 결과를 비교 분석하고자 한다. 대상 및 방법: 2009년 8월부터 2014년 12월까지 방사선 영상상 AO/OTA 분류 31-A2 대퇴골 전자간부 골절로 진단되어 골수강 내 금속정을 이용한 내고정을 시행한 뒤 최소 1년 이상 추시가 가능하였던 65세 이상의 환자 139예를 대상으로 후향적 대조군 연구를 시행하였다. 대상군을 짧은 골수정(I군)과 긴 골수정(II군)을 사용한 군으로 분류하였으며 각각 106예, 33예로 조사되었다. 방사선적인 평가로 골절의 정복 정도, 골유합까지의 기간, 합병증 발생을 조사하였으며 수술 전 혈색소, 수술 시간, 수술 중 출혈량, 수혈 유무, 입원 기간 및 최종 추시 시 Charnley 고관절 점수를 통한 임상적 평가를 시행하였다. 결과: 수술 후 단순 방사선 검사상 전 예에서 good 또는 acceptable한 정복 상태를 얻었다. 골유합까지 평균 4.8개월이 걸렸으며 두 군 간의 차이는 없었다. II군(57.87분)이 I군(45.65분)보다 수술 시간이 길었던 것으로 확인되었다(p=0.003). 수술 중 출혈량의 경우 II군(288.78 ml)이 I군(209.90 ml)보다 많은 것으로 확인되었다(p=0.046). 최종 추시 시 임상적 결과는 두 군 모두 만족스러웠다. 결론: 고령의 환자에서 발생한 후내측 골편을 동반한 불안정성 대퇴골 전자간부 골절의 치료 시 골절 부위의 정복을 잘 시행한 경우 긴 골수정과 짧은 골수정 모두 만족스러운 방사선적, 임상적 결과를 보였다.

• Archives of Plastic Surgery
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• 제34권6호
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• pp.813-817
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• 2007

Purpose: The zygomatic arch is a key element which composes the facial contour. In many cases of zygomatic arch fracture, it is difficult to fix rigidly the fractured segments. If reduced bone segments were not fixed rigidly, they are proven to be displaced by mastication or unintentional external forces. So, unfixed zygomatic arch fracture after reduction may require a external device of prevention of collapse. We introduce a new protector which stabilizing the fractured segments to prevent for collapse of the reduced zygomatic arch fracture. Methods: After reduction of zygomatic arch with blind approach(Gillies', Dingman or Keen's approach), bone segments was pulled with percutaneous traction suture in medial aspect of zygomatic arch. Then, the suture was fixed with Aqua $splint^{(R)}$, externally. And intraoperative and postoperative X-ray was done. The splint was removed on 14 days after the operation. Results: 5 patients were treated with this method. 4 patients of total patients had no collapse in zygomatic arch. There was minimal collapse in one patient. Postoperative complications such as facial nerve injury, mouth opening difficulty, contour deformity, infection, scar were not observed. Conclusion: In comparison with other techniques, this technique has several advantages which are simple and easy method, short operation time, no scar, less soft tissue injury, and facilitated removal of splint. Therefore, Aqua $splint^{(R)}$ would be a good alternative to prevent for collapse in unstable zygomatic arch fractures