4.Sutureless aortic valve implantation: first experience in Asia.
Guohao CHANG ; duc Thang VU ; Kristine Leok Kheng TEOH ; Lian Kah TI ; Theodoros KOFIDIS
Singapore medical journal 2014;55(11):598-600
Age-related degenerative calcification is currently the most common cause of aortic stenosis (AS) in adults and the most frequent reason for aortic valve replacement in patients with AS. With the increased life expectancy, a large proportion of elderly patients with AS is undergoing cardiac surgery, although many are not offered conventional aortic valve replacement due to the risks involved. However, sutureless aortic valve replacement provides an alternative for this group of elderly patients. This case series reports the first experience in Asia of sutureless aortic valve implantation in seven patients at our institution.
Aortic Valve Stenosis
;
epidemiology
;
surgery
;
Asia
;
epidemiology
;
Heart Valve Prosthesis
;
Heart Valve Prosthesis Implantation
;
methods
;
Humans
6.Percutaneous transhepatic biliary radiofrequency and endoprothesis: a new therapy for malignant biliary obstruction.
Guo-Lin HE ; Xiao-Ping XU ; Chen-Jie ZHOU ; Yuan CHENG ; Ming-Xin PAN ; Yi GAO ; Ze-Sheng JIANG
Journal of Southern Medical University 2011;31(4):721-723
OBJECTIVETo explore a new approach to the management of malignant biliary obstruction using percutaneous transhepatic biliary radiofrequency and endoprothesis.
METHODSPercutaneous transhepatic biliary radiofrequency and endoprothesis were performed in 2 cases of malignant biliary obstruction, including 1 of hilar cholangiocarcinoma and 1 of pancreatic head carcinoma. The tumor was ablated with radiofrequency followed by placement of matched metal stents into the biliary duct.
RESULTSThe surgical procedures were carried out smoothly in the 2 cases. The symptoms of the patients were obviously improved after the operation with a significant decrease in the serum levels of total bilirubin, and CA-199 level decreased to the normal level in 1 case.
CONCLUSIONSThis new approach is safe for management of malignant biliary obstruction. Compared with the more conventional interventional therapy, radiofrequency can reduce the intraoperative bleeding and arrest the local tumor growth to promote the patency of the stent as well as the postoperative survival of the patients.
Adult ; Aged ; Catheter Ablation ; methods ; Female ; Humans ; Jaundice, Obstructive ; etiology ; surgery ; Male ; Prosthesis Implantation ; methods ; Stents
7.Stress analysis of the staggered and straight placement of implants in the mandibular posterior region under the localized load.
Ying LI ; Yan-min ZHOU ; Zhen-ping ZHOU ; Xin WANG
Chinese Journal of Stomatology 2007;42(6):365-367
OBJECTIVETo compare the stress distribution of the staggered and straight placement of implants in the mandibular posterior region.
METHODSUsing three-dimensional finite element approach to analyze the stress distribution and variance regularity under the localized load.
RESULTSUnder vertical load, the stress peak value reduced when wide implant was placed straight (min: 3.70 MPa), but slightly increased when normal implant was placed staggered (max: 8.32 MPa); under the inclined load from buccal to lingual direction, the stress peak value reduced when the wide implant was placed in straight line (min: 12.29 MPa) or normal implant was placed staggered with buccal offset configuration (min: 15.48 MPa), but increased with lingual offset configuration (max: 23.60 MPa).
CONCLUSIONSWide implant (> or = 4 mm) with straight placement should be adopted to reduce the stress peak value and improve stress distribution, when the buccolingual diameter of the alveolar ridge in the mandibular posterior region was wide.
Adult ; Dental Implantation, Endosseous ; methods ; Dental Prosthesis Design ; Dental Prosthesis, Implant-Supported ; Dental Stress Analysis ; Finite Element Analysis ; Humans ; Mandible
8.Finite element method and computational fluid dynamics used in the analysis of a stent.
Dongke LIANG ; Dazhi YANG ; Min QI
Journal of Biomedical Engineering 2007;24(3):549-553
Stent implantation can cause thrombus, vessel injury and blood flow disturbance which are considered as the main causes of instent restenosis. In order to investigate the influence of stent implantation on vessel wall and blood flow, we used finite element method (FEM) and computational fluid dynamics (CFD) in this work. The results showed that the implantation of the stent could cause vessel injury and flow stagnation. The instant recoil of the implanted stent is much more than that of the stent itself (12.3% versus 3.1%). In conclusion, FEM and CFD can help illustrate and quantify some biomechanical characteristics for the optimization of stent design.
Blood Flow Velocity
;
physiology
;
Computer Simulation
;
Finite Element Analysis
;
Humans
;
Models, Cardiovascular
;
Prosthesis Design
;
Prosthesis Implantation
;
methods
;
Stents
;
adverse effects
9.Augmentation with Transcortical Wiring of an Onlay-type Prosthesis for a Deficient Patella during Revision Total Knee Arthroplasty.
Jai Gon SEO ; Young Wan MOON ; Seung Jae LIM ; Ji Soon LIM ; Sang Min KIM
Clinics in Orthopedic Surgery 2012;4(2):163-166
The management of patellae with a severe bony deficiency during revision total knee arthroplasty is a challenging problem. However, using a technique of augmentation with transcortical wiring of an onlay-type prosthesis allowed the authors to revise a deficient patellae successfully. After making the decision to revise the existing patellar component, the procedure was found to be technically straightforward. Furthermore, the procedure does not require sophisticated instruments, only an onlay-type prosthesis, cement and wires. This technique entails fixing wires to the three pegs of the patellar component, passing the wires through drill holes in the anterior cortex and, after compression of a cemented prosthesis, augmenting the fixation by twisting the wires anteriorly. We believe that stable fixation and painless articulation will be obtained with the described technique for deficient patellae.
Aged
;
Aged, 80 and over
;
Arthroplasty, Replacement, Knee/*methods
;
Bone Cements
;
*Bone Wires
;
Humans
;
Knee Prosthesis
;
Middle Aged
;
Patella/*surgery
;
Prosthesis Design
;
Prosthesis Implantation/*methods
10.Preliminary study of a new heart valve prostheses implanted with minimally invasive techniques: pulsatile-flow testing in vitro.
Jinglong TANG ; Shuo WANG ; Li LIU ; Jian WANG ; Chunren WANG
Journal of Biomedical Engineering 2013;30(1):166-169
The aim of this study was to investigate the pulsatile-flow performance in vitro of a new heart valve prostheses implanted with minimally invasive techniques (HVPMIT). Three HVPMITs were tested valves and another three original biological heart valve prostheses acted as reference valves. The pulsatile-flow parameters (including mean pressure drop, regurgitant percentage of stroke volume, and effective orifice area) were tested in a pulse duplicator according to the methods listed in ISO5840-2005 and GB 12279-2008. The results demonstrated that the regurgitant percentage of stroke volume of tested valves was up to 13%. It was significantly higher than that of the reference valves. This result suggested that paravalvular leakage had occurred in the tested valves. It was found in the further analysis that because HVPMIT was not sewn into the heart tissue when the HVPMIT was implanted in vivo and there was not a sewing ring in the HVPMIT, when tested valves were fixed in the pulse duplicator, some gaps might exist between the stent of HVPMIT and the fix gasket, and the paravalvular leakage could therefore take place through these gaps. This study demonstrated that there are significant differences in the shape, structure, fixation in vivo and clinical operational methods between HVPMIT and original biological heart valve prostheses. It is necessary to establish new test methods which adapt for HVPMIT to evaluate its pulsatile-flow performance according to its own features.
Animals
;
Cardiac Catheterization
;
Heart Valve Prosthesis
;
Heart Valve Prosthesis Implantation
;
adverse effects
;
instrumentation
;
methods
;
Minimally Invasive Surgical Procedures
;
methods
;
Prosthesis Design
;
Pulsatile Flow