• 제목/요약/키워드: Clearance margin

검색결과 14건 처리시간 0.017초

3-Dimensional fasciectomy: A highly efficacious common ground approach to Dupuytren's surgery

  • Miranda, Benjamin H;Elliott, Charlotte;Kearsey, Christopher C;Haughton, David N;Webb, Mark R;Harvey, Ian;Fahmy, Fahmy S
    • Archives of Plastic Surgery
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    • 제45권6호
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    • pp.557-563
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    • 2018
  • Background Numerous Dupuytren's fasciectomy techniques have been described, each associated with unique surgical challenges, complications and recurrence rates. We describe a common ground surgical approach to Dupuytren's disease; 3-dimensional fasciectomy (3DF). 3DF aims to address the potential contributors to the high recurrence rate of Dupuytren's disease and unite current limited fasciectomy practice that varies considerably between surgeons. Methods We describe the 3DF principles; raising thin skin flaps (addressing dermal involvement), excising diseased palmar fascia with a 3-5 mm clearance margin (treating highly locally recurrent conditions) and excising the vertical septae of Legueu and Juvara (providing deep clearance, hence addressing all potentially involved pathological tissue). The surgical outcomes between traditional limited fasciectomy (LF) and 3DF are compared. Results From the 786 operations included (n=585), postoperative recurrence rates were significantly lower for the 3DF group (2/145, 1.4%) than the LF group (72/641, 11.2%) (P= 0.001), and the time to recurrence was significantly longer ($5.0{\pm}0years$ vs. $4.0{\pm}0.2years$; P<0.0001). With recurrence excluded, there were no differences between the postoperative complication rates for 3DF (5/145, 3.5%) and LF (41/641, 6.4%) (P=0.4). Conclusions Our results suggest that 3DF leads to lower recurrence rates and a longer disease-free period for patients, without increasing complications. 3DF provides a safe, efficacious, common ground surgical approach in the treatment of Dupuytren's flexion deformity.

카테너리 각도를 이용한 가공송전도체의 이도 추정 (Dip Estimation for Overhead Transmission Conductor using Catenary Angle)

  • 김성덕;손홍관;장태인
    • 조명전기설비학회논문지
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    • 제21권5호
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    • pp.112-119
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    • 2007
  • 가공송전 도체는 정상 동작조건 하에서 전력회사의 선로 설계지침에 규정된 지상고를 안정범위 내에서 항상 유지할 수 있어야 한다. 따라서 새로운 선로를 건설하거나 노화도체의 장력을 다시 조정하거나 또는 전력용량을 최대화하기 위해 동적송전용량을 모니터링하는 경우에, 도체 이도를 측정/또는 모니터링하는 것은 매우 중요하다. 본 연구에서는 도체의 카테너리 각도로 이도 및 장력을 추정하기 위한 새로운 방법을 제안한다. 가공송전선로의 대부분의 도체들은 전형적인 카테너리 곡선을 나타내므로 철탑 측의 카테너리 각도로부터 도체의 카테너리 곡선을 유일하게 결정할 수 있다. 이 카테너리 곡선을 토대로 도체의 이도나 수평장력을 쉽게 추정할 수 있다. 몇 가지 시뮬레이션과 간단한 실험 결과를 통하여 제안된 방법이 가공송전선의 도체 이도와 장력을 측정/또는 모니터링하는데 효과적으로 사용될 수 있음을 확인하였다.

프로세스 고속 경량 원심 압축기의 로터다이나믹 안정성 강화를 위한 설계해석 - Part II: 로터다이나믹 안정성 개선 (Design Analysis for Enhancing Rotordynamic Stability of Process High-Speed Light weight Centrifugal Compressor - Part II: Improvements to Rotordynamic Stability)

  • 이안성
    • Tribology and Lubricants
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    • 제30권1호
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    • pp.9-14
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    • 2014
  • In this Part II study, rotordynamic stability analyses were carried out to confirm improvements to the stability of a process high-speed lightweight centrifugal compressor, depending on the effects of tilting pad journal bearing designs. The bearing design variables considered were the clearances, LBPs, LOPs, and preloads. The results showed that the rotordynamic stability of the subject compressor rotor-bearing system improves exactly in accordance with the effects of the bearing design variables, which were determined in the preceding Part I study, owing to reduced bearing stiffnesses. Specifically, it was confirmed that the stability of the rotor system can be greatly improved by increasing both the machined and assembled bearing clearances, but there were no stability improvements by simply changing from an LBP to an LOP design. In addition, it was confirmed that for given fixed machined bearing clearances, the stability can be additionally improved by decreasing the preloads, i.e., by increasing the assembled clearances. In conclusion, it may be necessary to improve the designs of the original tilting pad bearings to obtain a sufficient margin of rotordynamic stability against a possible aerodynamic cross-coupled stiffness in a process high-speed centrifugal compressor. Thus, increasing the machined and assembled bearing clearances and decreasing the preload could be effective solutions.

Merkel cell carcinoma: A series of seven cases

  • Lee, Yong Woo;Bae, Yong Chan;Nam, Su Bong;Bae, Seong Hwan;Kim, Hoon-Soo
    • Archives of Plastic Surgery
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    • 제46권5호
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    • pp.441-448
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    • 2019
  • Background Merkel cell carcinoma (MCC) is a rare neuroendocrine malignancy affecting the skin, for which timely diagnosis and aggressive treatment are essential. MCC has most often been reported in Caucasians, and case reports in Asians are rare. This study presents our experiences with the surgical treatment and radiotherapy of MCC in Asian patients. Methods We retrospectively reviewed the records of seven MCC patients between 2000 and 2018 from a single institution, and analyzed patient characteristics, tumor characteristics, surgical treatment, sentinel lymph node evaluation, reconstruction, adjuvant radiation therapy, and prognosis. Results Eight MCC lesions occurred in seven patients, most commonly in the head and neck region. All patients underwent surgical excision with reconstruction. The final surgical margin was 1.0 cm in most cases, and reconstruction was most commonly performed with a splitthickness skin graft. Five patients received adjuvant radiotherapy, and two patients received sentinel lymph node biopsy. During the follow-up period, three patients remained well, two died from other causes, one experienced recurrence, and one was lost to follow-up. Conclusions We treated seven Asian MCC patients and our series confirmed that MCC is a very dangerous cancer in Asians as well. Based on our experiences, thorough surgical excision of MCC with histopathological clearance should be considered, with sentinel lymph node evaluation if necessary, followed by appropriate reconstruction and careful postoperative observation. Adjuvant radiation therapy is also recommended for all Asian MCC patients. The results of this case series may provide guidance for the treatment of Asian MCC patients in the future.