This paper proposed a new design on multi-layer flexible microelectrode arrays (MEA) of epiretinal prosthesis, as well as a set of automatic testing system to evaluate and analyze the MEA. Experiment results showed that the MEA was satisfying on both flexibility and impedance and the multi-layer design didn't introduce significant differences.
Microarray Analysis ; Microelectrodes ; Prostheses and Implants ; Prosthesis Design ; Prosthesis Implantation ; instrumentation ; Retina

Cardiac Catheterization ; Heart Septal Defects, Ventricular ; therapy ; Humans ; Prosthesis Implantation ; instrumentation ; Septal Occluder Device

Cochlear Implantation ; instrumentation ; Cochlear Implants ; Electrodes ; Female ; Humans ; Infant ; Prosthesis Failure

Adult ; Aged ; Aortic Aneurysm, Abdominal ; surgery ; Blood Vessel Prosthesis Implantation ; instrumentation ; Female ; Humans ; Male ; Middle Aged

OBJECTIVETo evaluate the feasibility and effectiveness of transcatheter transapical implantation of a new domestic balloon-expandable bioprosthetic aortic valve in goats.

METHODSWe developed a new tube-like balloon-expandable bioprosthetic aortic valve which was made from cobalt-chromium alloy and bovine pericardium. Briefly, fresh bovine pericardium was trimmed into artificial leaflets and sutured into the cobalt-chromium alloy stent by hand post cell extracting and anti-calcification treatments. A left anterolateral mini-thoracotomy was performed in the 5(th) intercostal space of 5 goats. After opening the pericardium, the apex of the left ventricle was punctured, a stiff guidewire was positioned across the aortic arch and anchored in the descending aorta. The delivery catheter (22 F) was then introduced through the stiff guidewire into the aorta arch under fluoroscopic guidance. After correct valve position was confirmed by digital subtraction angiography, the valved stent was implanted after rapid inflation of the balloon. The immediate results of implanted valved stents were evaluated with angiography and echocardiography.

RESULTSFour devices were successfully implanted into aortic valve position of goats and one goat died of severe aortic valve regurgitation because the valved stent was implanted below the normal position.Immediate observation after procedure in 4 goats by angiography and echocardiography showed that the valved stents were in the desired position after implantation. Mild paravalvular leakage were found in 3 out of the 4 survived goats and there were no moderate to severe aortic regurgitation in survived goats.

CONCLUSIONThe procedure of transcatheter transapic aortic valve implantation with our new-type domestic balloon-expandable valved stent and delivery system is feasible and effective.

Animals ; Aortic Valve ; Catheterization ; Cattle ; Female ; Goats ; Heart Valve Prosthesis Implantation ; instrumentation ; methods ; Male ; Stents

Arteries ; surgery ; Arteriosclerosis Obliterans ; surgery ; Bioprosthesis ; Blood Vessel Prosthesis ; Blood Vessel Prosthesis Implantation ; instrumentation ; Humans ; Lower Extremity ; blood supply ; surgery

OBJECTIVEThe purpose of this study was to determine the feasibility of transcatheter pulmonary valve replacement in sheep up to 6 months post procedure.

METHODSFresh sheep pericardium treated with a 0.6% glutaraldehyde solution for 36 hours was sutured to a valvular ring and then fixed onto a newly designed nitinol self-expandable stent. Thoracotomy was performed in sheep (23.5 +/- 3.1) kg under general anesthesia and the device was delivered into the native pulmonary valve of the sheep via the anterior wall of right ventricle by catheter and fooled for 6 months.

RESULTSOne sheep died 4 months after the procedure due to in-stent thrombosis. Another 4 animals survived the 6-month observing period. Angiographic and hemodynamic measurements confirmed good positioning and function of the stents with a competent valve immediately post procedure and 6 months post the procedure in surviving animals.

CONCLUSIONImplantation of the nitinol self-expandable stent in the pulmonary valve position by a transcatheter approach is feasible and good function of transcatheter implanted memory nitinol valved stents was shown after 6 months of implantation in sheep.

Animals ; Disease Models, Animal ; Female ; Heart Valve Prosthesis ; Heart Valve Prosthesis Implantation ; instrumentation ; methods ; Male ; Pulmonary Valve ; surgery ; Sheep ; Stents

OBJECTIVEThe feasibility and clinical effects of hollow obturator prosthesis for the repair of maxillofacial defect immediately after maxillectomy for cancer were assessed.

METHODSThirteen patients with T3-4aN0M0 maxillary neoplasm were treated by the prostheses immediately after maxillectomy. According to the 3D-CT reconstruction of nasal sinus, the 3D stereoscopic prototype was constructed before the surgery. Simulating surgery with Surgicare 5.0 software and then the prosthesis 3D stereoscopic model was shaped. The prosthesis was made quickly and precisely with methacrylate resins according to the model and the print mold before surgery, with supplementary tooth at the bottom of prosthesis. In the surgery, the prosthesis was installed instantly after maxillectomy. The patients were followed up at 1, 3 and 6 month after the surgery, respectively. The facial features and the pronunciation clarity were examined and the questionnaires were carried out in the patients, with comparation by paired t-test. The hollow obturator prosthesis would be replaced by permanent prosthesis made of methacrylate resins at 6 month after the surgery.

RESULTSThe hollow obturator prostheses were installed accurately and maxillofacial defects were repaired immediately after maxillectomy in the 13 patients. Postoperative follow-up showed there were significant differences in eyeball sagging (t = 4.67, P < 0.05), mid-facial region collapse (t = 5.67, P < 0.05), and pronunciation clarity (t = 16.38, P < 0.05) between patients with and without prostheses. Questionnaires showed that all the patients were satisfied with the retention of prostheses, the improvement of appearance, the improvement of the symptom of water choking and speech definition. Six months after the surgery, the hollow obturator prostheses were replaced smoothly by permanent prostheses in 11 of the 13 patients.

CONCLUSIONThe precise and instant repair of maxillofacial defect by prosthesis after maxillectomy can improve survival quality of patient.

Adult ; Aged ; Denture, Partial, Immediate ; Female ; Humans ; Male ; Maxillary Neoplasms ; surgery ; Maxillofacial Prosthesis Implantation ; Middle Aged ; Prosthesis Implantation ; Reconstructive Surgical Procedures ; instrumentation ; methods

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

OBJECTIVETo explore long-term effect of the treatment of refractory benign esophageal strictures with a novel retrievable fully covered stent made of nitinol alloy.

METHODSFrom November 2009 to May 2011, the stents were placed in 8 patients with refractory benign esophageal strictures in the Department of Thoracic Surgery at the Cancer Center of Sun Yat-sen University. Esophago-gastro-duodenoscopy and barium swallow examinations were performed respectively on the 1st, 7th, 30th, 60th day after implantations of the stents and 1,2,3,6 months or even longer after removal of the stents in order to assess the long-term effect on the improvement of dysphagia and the development of complications.

RESULTSThe stents were successful deployed in all the patients. The dysphagia scores were improved instantly and significantly as compared to the preoperative scores(P<0.05). Seven patients had long-term improvement of dysphagia. The dwelling time of all the stents ranged from 4 to 60 weeks, with a median of 16.8 weeks. Six patients had their stent removed after a dwelling time of 4 to 18 weeks(median 9.7 weeks). The follow-up period was 1.5-9 months (median 6.1 months). The improvement of dysphagia was also significant during follow-up after removal of the stents(P<0.05). At the most recent follow up, two patients still had the stent in place. The first one has already been followed up for 15 months and was still on regular diet. The other one experienced improvement of dysphagia score up to two months after placement, but downgraded to 3 by the third month. Relapse of stenosis occurred in 1 patient, migration in 2 patients, and tissue hyperplasia in 3 patients, of whom 2 developed inward growth of granulation tissue due to the rupture of the covering membrane.

CONCLUSIONSThe new retrievable fully covered stent made of nitinol alloy significantly improves the swallowing function of patients with intractable benign esophageal strictures after implantation and after removal of the stents, with low incidence of long-term restenosis. However, the high rate of migrations and the poor quality of the covering membrane further implies that the design of the new stent still needs to be improved.

Adult ; Aged ; Alloys ; Esophageal Stenosis ; surgery ; Female ; Humans ; Male ; Middle Aged ; Prosthesis Implantation ; instrumentation ; methods ; Stents ; Treatment Outcome