• Title/Summary/Keyword: Mesh-up

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Cranioplasty and temporal hollowing correction with a three-dimensional printed bioresorbable mesh and double vertical suture anchor muscle sling: a case report

  • Choi, Jae Hyeok;Roh, Tai Suk;Lee, Won Jai;Baek, Wooyeol
    • Archives of Craniofacial Surgery
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    • v.23 no.4
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    • pp.178-182
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    • 2022
  • Postoperative temporal hollowing is a common complication of craniotomy. Damage and repositioning of the temporalis muscle can lead to a depression in the temporal side of the skull with inferior bulging, worsening aesthetic outcomes. We report a case of cranioplasty with three-dimensional (3D) printed mesh involving an additional correction using a temporalis muscle sling to help address this problem. A 3D-printed bioabsorbable mesh was prepared based on preoperative facial computed tomography, and was fixed to the hollowed area for tissue augmentation. The temporalis muscle was elevated and fanned out to its original position, and a sling was attached to a screw that was fixed to the mesh. For reinforcement, an additional sling was attached to another screw fixed to the mesh 2-3 cm vertically above the first screw. Aesthetic results were confirmed immediately after surgery and later during outpatient follow-up. Both depression and lateral bulging were resolved, and there was no delayed drooping of the temporalis muscle on 6-month follow-up. There were no complications, and the patient was satisfied with the appearance. This is a simple yet effective technique with a low risk of complications, and should be considered for postoperative temporal hollowing patients, especially those with severe lateral bulging.

Clinical Usefulness of Titanium Mesh in Reconstruction of the Craniofacial Bone Defects (두개안면골 결손부 재건에 있어서 티타늄 그물판의 임상적 유용성)

  • Seo, Yeong Min;Jeong, Seung Moon
    • Archives of Plastic Surgery
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    • v.33 no.6
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    • pp.688-694
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    • 2006
  • Purpose: Reconstruction of the craniofacial defects can be carried out with autogenous tissues, allogenic implants, or alloplastic materials. Titanium mesh systems have been used for bony reconstruction in non load-bearing areas. They offer several advantages: immediate availibility without any donor site morbidity, easy handling, stable 3-D reconstruction, and low susceptibility to infection. The aim of this study is to evaluate the usefulness and complications of titanium mesh system in the reconstruction of the craniofacial defects. Methods: From Jan. 2000, to Dec. 2004, we performed reconstruction of craniofacial bone defects in 21 patients who had benign or malignant tumor and fracture events in the cranium, orbit, nasal bone, maxilla, zygoma and the mandible. The size of the defects ranged from $1.0{\times}1.5cm$ to $12{\times}10cm$. Two different mesh systems, micro-titanium augmentation mesh and dynamic mesh was used for bony reconstruction in non load-bearing areas. The patients were evaluated from 1 to 4 yrs clinically and radiographically with a mean follow up period of 1.5 yrs. Results: There were no serious complications, including wound infection, foreign body reaction, exposures or loos of the mesh, central infection and pathologic findings of bone around mesh exception of one patient, who had expired of skull base tumor recurrence. Long-term stability of the reconstructions and the overall functional and aesthetic outcome was excellent. Conclusion: Our experiences demonstrate that the Titanium mesh system is a relatively safe and efficient method in the craniofacial reconstruction and have broadens our choices of therapeutic procedures in the craniomaxillofacial surgery.

Adaptive mesh generation for plane stress problems using error based on element′s representative strain value (요소의 대표 변형률 값에 근거한 에러평가를 이용한 평면응력문제의 적응적 요소망 형성)

  • 정요찬;윤종열;홍승표
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.403-409
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    • 2003
  • The finite element method is one of the most widely used method of structural analysis that has wide applications in diverse fields of engineering and science. The method has been proven effective and reliable in many practical problems. One of the reasons for the methods' popularity is its ease of use, but still the user has to input the finite element mesh which affects the accuracy of the results. The knowledge required to form an effective mesh for a given problem is somewhat complex and for sometime there has been research effort to automate the generation of the mesh and this is called the adaptive mesh generation scheme. A good adaptive mesh scheme seemed to require an accurate assessment of error and generally this requires some additional computation. This paper looks into the possibility of generating adaptive meshes based on representative strain values in each finite element method. The proposed adaptive scheme does not require additional computations other that looking up the data values already computed as finite element analysis results and simple manipulations of these data. Two plane stress problems, a plate with a hole and a deep beam with a concentrated load at the end are considered to show the progress of the improved generation of adaptive meshes using the scheme.

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3D Automatic Mesh Generation Scheme for the Boundary Element Method (경계요소법을 위한 3차원 자동요소분할)

  • Lee, H.B.;Lee, S.H.;Kim, H.S.;Lee, K.S.;Hahn, S.Y.
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.935-937
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    • 1993
  • This paper presents a three dimensional automatic mesh generation scheme for the boundary element method, and this scheme can be applicable to practical problems of complex shape. The geometry of the problem is expressed as an assemblage of linear Coon's surfaces, and each surface is made up of four edge curves which are defined in the form of a parametric function. Curves are automatically segmented according to their characteristics. With these segments of curves, interior points and triangular mesh elements are generated in the parametric plane using Lindholm's method, and then their projection on the real surface forms the initial mesh. The refinement of initial mesh is performed so that the discrete triangular planes are close to the real continuous surfaces. The bisection method is used for the refinement. Finally, interior points in the refined mesh are rearranged so as to make each element be close with an equilateral triangle. An attempt has been made to apply the proposed method to a DY(Deflection Yoke) model.

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Adaptive Wireless Network Coding for Infrastructure Wireless Mesh Networks

  • Carrillo, Ernesto;Ramos, Victor
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.7
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    • pp.3470-3493
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    • 2019
  • IEEE 802.11s-based infrastructure Wireless Mesh Networks (iWMNs) are envisaged as a promising solution to provide ubiquitous wireless Internet access. The limited network capacity is a problem mainly caused by the medium contention between mesh users and the mesh access points (MAPs), which gets worst when the mesh clients employ the Transmission Control Protocol (TCP). To mitigate this problem, we use wireless network coding (WNC) in the MAPs. The aim of this proposal is to take advantage of the network topology around the MAPs, to alleviate the contention and maximize the use of the network capacity. We evaluate WNC when is used in MAPs. We model the formation of coding opportunities and, using computer simulations, we evaluate the formation of such coding opportunities. The results show that as the users density grows, the coding opportunities increase up to 70%; however, at the same time, the coding delay increments significantly. In order to reduce such delay, we propose to adaptively adjust the time that a packet can wait to catch a coding opportunity in an MAP. We assess the performance of moving-average estimation methods to forecast this adaptive sojourn time. We show that using moving-average estimation methods can significantly decrease the coding delay since they consider the traffic density conditions.

TREATMENT OF THE 'BLOW-OUT' FRACTURE USING MICRO-TITANIUM MESH (Micro-titanium mesh를 이용한 안와저 골절의 외과적 처치에 대한 연구)

  • Kim, Seong-Gon;Jeon, Young-Du;Yun, Kyoung-In
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.21 no.3
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    • pp.312-316
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    • 1999
  • When the external force was applied to the orbit the most thin area might be displaced. These were usually orbital floor and/or medial wall of orbit. Among these cases some who showed the entrapment of the muscle between the fractured fragments needed the surgical treatment. We had operated 4 cases of the "blow-out" fracture via subciliary approach. The entrapped muscles were freed from fragments and the bony defect was restored with micro-titanium mesh. Mean follow-up periods was 15 months and there were no complication observed.

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Comparison of Sequelae According to the Types of Implants in Blow-Out Fracture (안와 파열 골절 치료 시 삽입물 종류에 따른 후유증 비교)

  • Kim, Tae-Gon;Im, Jong-Hyo;Lee, Jun-Ho;Kim, Yong-Ha
    • Archives of Craniofacial Surgery
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    • v.10 no.1
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    • pp.23-28
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    • 2009
  • Purpose: Blow out fracture can present tenderness, swelling, enophthalmos, extraoccular muscle limitation, paresthesia, diplopia according to severity of injury, so reconstruction of blow out fracture is important. Orbital soft tissue should be in orbit and defected orbital wall should be corrected by autologus tissue or alloplastic implants. Every implants have their merits and faults, every implants are used various. This study was designed to compare the sequelae of blow-out fracture repair using the alloplastic implants: micro-titanium mesh(Micro Dynamic titanium $mesh^{(R)}$, Leibinger, Germany), porous polyethylene ($Medpor^{(R)}$, Porex, USA), absorbable mesh plate(Biosorb $FX^{(R)}$ . Bionx Implants Ltd, Finland). Methods: Between January 2006 and April 2008, 52 patients were included in a retrospective study analysing the outcome of corrected inferior orbital wall fracture with various kind of implants. Implants were inserted through subciliary incision. Twenty patients were operated with micro-titanium mesh, fourteen patients with porous polyethylene and eighteen patients with absorbable mesh plate. In comparative category, enophthalmos, diplopia, range of motion of extraoccular muscle, inferior orbital nerve injury were more on frequently statistically in patients. Results: Fourteen of 18 patients underwent surgical repair to improve diplopia, 11 of 17 patients to improve parasthesia, 11 of 15 patients to improve enophthalmos, 8 of 9 patients to improve extraoccular muscle limitation. Duration of follow-up time ranged from 6 months to 12 months(mean, 7.4 months). There was no statistic difference of sequelae between micro titanium mesh and porous polyethylene and absorbable mesh plate in blowout fracture, inferior wall. Conclusion: There is no difference of sequelae between micro-titanium mesh, porous polyethylene and absorbable mesh plate in blow-out fracture, inferior wall. The other factors such as defect size, location, surgeon's technique, may influence the outcome of blow-out fracture repair.

Is Titanium Mesh Cage Safe in Surgical Management of Pyogenic Spondylitis?

  • Heo, Won;Kang, Dong-Ho;Park, Kyung-Bum;Hwang, Soo-Hyun;Park, In-Sung;Han, Jong-Woo
    • Journal of Korean Neurosurgical Society
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    • v.50 no.4
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    • pp.357-362
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    • 2011
  • Objective : To report our experience with pyogenic spondylitis treated with anterior radical debridement and insertion of a titanium mesh cage and to demonstrate the effectiveness and safety of the use of a titanium mesh cage in the surgical management of pyogenic spondylitis. Methods : We retrospectively analyzed the clinical characteristics of 19 patients who underwent surgical treatment in our department between January 2004 and December 2008. The average follow-up period was 11.16 months (range, 6-64 months). We evaluated risk factors, cultured organisms, lab data, clinical outcomes, and radiographic results. Surgical techniques for patients with pyogenic spondylitis were anterior radical debridement and reconstruction with titanium mesh cage insertion and screw fixation. All patients received intravenous antibiotics for at least 6 weeks postoperatively, and some patients received oral antibiotics. Results : The infections resolved in all of the patients as noted by normalization of their erythrocyte sedimentation rates and C-reactive protein levels. The mean pain score on a Visual Analog Scale was 7.8 (range, 4-10) before surgery and 2.4 (range, 1-5) after surgery. The Frankel grade was improved by one grade in seven patients. After surgery, the average difference of the angle was improved about $6.96^{\circ}$ in all patients. At the last follow-up, the mean loss of correction was $4.86^{\circ}$. Conclusion : Anterior radical debridement followed by the placement of instrumentation with a titanium mesh cage may be a safe and effective treatment for selected patients with pyogenic spondylitis. This surgical therapy does not lead to recurrent pyogenic spondylitis.

Improved structures of stainless steel current collector increase power generation of microbial fuel cells by decreasing cathodic charge transfer impedance

  • Nam, Taehui;Son, Sunghoon;Kim, Eojn;Tran, Huong Viet Hoa;Koo, Bonyoung;Chai, Hyungwon;Kim, Junhyuk;Pandit, Soumya;Gurung, Anup;Oh, Sang-Eun;Kim, Eun Jung;Choi, Yonghoon;Jung, Sokhee P.
    • Environmental Engineering Research
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    • v.23 no.4
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    • pp.383-389
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    • 2018
  • Microbial fuel cell (MFC) is an innovative environmental and energy system that converts organic wastewater into electrical energy. For practical implementation of MFC as a wastewater treatment process, a number of limitations need to be overcome. Improving cathodic performance is one of major challenges, and introduction of a current collector can be an easy and practical solution. In this study, three types of current collectors made of stainless steel (SS) were tested in a single-chamber cubic MFC. The three current collectors had different contact areas to the cathode (P $1.0cm^2$; PC $4.3cm^2$; PM $6.5cm^2$) and increasing the contacting area enhanced the power and current generations and coulombic and energy recoveries by mainly decreasing cathodic charge transfer impedance. Application of the SS mesh to the cathode (PM) improved maximum power density, optimum current density and maximum current density by 8.8%, 3.6% and 6.7%, respectively, comparing with P of no SS mesh. The SS mesh decreased cathodic polarization resistance by up to 16%, and cathodic charge transfer impedance by up to 39%, possibly because the SS mesh enhanced electron transport and oxygen reduction reaction. However, application of the SS mesh had little effect on ohmic impedance.

Dry Milling Process of Barley Kernels (건식 보리 제분공정에 관한 연구)

  • Mok, Chul-Kyoon;Lee, Sang-Hyo;Lee, Hyun-Yu;Nam, Young-Jung
    • Applied Biological Chemistry
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    • v.28 no.3
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    • pp.115-123
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    • 1985
  • The milling characteristics of barley of various moisture content were investigated using Brabender Grain Hardness Tester (GHT) to set up the optimum conditions of dry milling process. The optimum GHT clearance were 1/0-1/10 for-10+12 mesh particles, 0/5-0/15 for-12+18 mesh, and 0/-15 for -18 mesh. The grain hardness of barley kernel increased with moisture content and the grindability, on the other hand, decreased. The consumed electric energy in milling increased with moisture content and showed the maximum value at the moisture content of 14.04%. The optimum conditions of dry milling of barley were 0/-5 GHT clearance and 12.80% moisture content and the consumed electric energy was 92.41Kwh for the production of 1,000kg of -18 mesh particles.

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