Prótese óculopalpebral com captação de movimento palpebral: proposta de dispositivo mecânico / Oculopalpebral prosthesis with eyelid motion capture: mechanical appliance proposition

Introdução: A reconstrução de grandes defeitos da face nem sempre é passível de correção cirúrgica, podendo ser restaurados com as próteses faciais. Apesar da prótese óculopalpebral apresentar uma aparência natural, ela é facilmente notada, pois não apresenta os movimentos palpebrais de abertura e fechamento sincronizadas com o olho contralateral, tornando assim a reconstrução protética um grande desafio. Objetivos: Planejar, desenhar, viabilizar e construir um protótipo com recurso mecânico/elétrico possibilitando sincronia dos movimentos palpebrais com o olho sadio para utilização em prótese óculopalpebral. Material e Métodos: Confecção de uma prótese óculopalpebral com um dispositivo de pálpebra móvel em silicone médico capaz de conectar-se a um sistema mecânico-elétrico responsável por realizar movimentos de abertura e fechamento da pálpebra móvel da prótese. Resultados e Discussão: Foi confeccionada uma prótese óculo-palpebral em resina acrílica termicamente ativada, criando-se um nicho para a acomodação de um sistema elétrico e possibilitar a livre movimentação de uma fina pálpebra em silicone interligada ao dispositivo tornando possível a conexão desse sistema com um sensor que capta o movimento palpebral de um olho saudável. Conclusão: No presente estudo um protótipo mecânico - elétrico foi planejado, desenhado e desenvolvido acoplado a uma prótese óculopalpebral estabelecendo e sincronizando seus movimentos palpebrais com o olho sadio.

Introduction: Surgical reconstruction of large facial defects may not be always possible. Extraoral maxillofacial prosthesis are a good restorative option. Even though when the oculopalpebral prosthesis presents a natural appearance, it can be easily noticed because its eyelids do not move. It is desirable for the eyelids to open and close synchronously with contralateral eye. Thus, prosthetic reconstruction of oculopalpebral region is a great challenge. Objectives: To plan, design, enable and build a oculopalpebral prosthesis prototype with mechanical and electric features allowing eyelid motion with synchronization with the sound eye. Material and method: Fabrication of an oculopalpebral prosthesis with a medical grade silicone movable eyelid which has the capability to connect itself to an mechanical-eletrical system responsible to make opening and closing movements on prosthesis movable eyelid. Results and discussion: An oculopalpebral prosthesis was made in thermoactivated acrylic resin. A gap was created to accomodate an electrical system and also allow free motion of a thin silicone eyelid attached to the dispositive. This system can be connected to a sensor which captured the eyelid motion of a sound eye. Conclusion: A mechanical-electrical prototype was planned, designed and developed attached to an oculopalpebral prosthesis stablishing and synchronizing its eyelid movements with the sound eye.

A new double-cone nitinol device for PDA occlusion: design, manufacturing and initial in vivo results.

Use of occluder devices for a patent ductus arteriosus (PDA) closure is restricted to small diameter PDAs and involves high device costs. The objective of this study was to develop a new nitinol implant for the closure of a PDA and to evaluate its safety and efficacy in an animal model. The design consists of a device that promotes thrombus formation in the PDA. The device has a double-cone shape with their vertices joined. The cones are made of a nitinol wire helix with dacron fibers attached. The proximal end of the helix can be screwed to a conventional catheter release wire. In vitro testing was performed to verify the effectiveness of the implantation of the device and its releasing system; all trials (n = 30) were successful, showing accurate placement and release of the device. Complete and successful implantation of the device was achieved in all in vivo experiments (n = 5). There was one case of embolization due to premature detachment; a second device was successfully implanted. Histological evaluation after 42.3 +/- 3.1 days demonstrated complete PDA occlusion. The retrieved PDA showed total closure of the defect, endothelization of the PDA outlets and proper lodging of the device.

Dimensional error of selective laser sintering, three-dimensional printing and PolyJet models in the reproduction of mandibular anatomy.

BACKGROUND: Selective laser sintering (SLS), three-dimensional printing (3DP) and PolyJet are rapid prototyping (RP) techniques to fabricate prototypes from virtual biomedical images. To be used in maxillofacial surgery, these models must accurately reproduce the craniofacial skeleton. PURPOSE: To analyze the capacity of SLS, 3DP and PolyJet models to reproduce mandibular anatomy and their dimensional error. MATERIAL: Dry mandible, helical CT images, SLS, 3DP and PolyJet prototypes, and digital electronic caliper. METHODS: Helical CT images were acquired from a dry mandible (criterion standard) and manipulated with the InVesalius software. Prototypes were produced using SLS, 3DP and PolyJet techniques. Thirteen linear measurements of each prototype were made and compared with the dry mandible measurements. RESULTS: The results showed a dimensional error of 1.79%, 3.14% and 2.14% for SLS, 3DP and PolyJet models, respectively. The models satisfactorily reproduced anatomic details and the SLS and PolyJet prototypes showed greater dimensional precision and reproduced mandibular anatomy more accurately than the 3DP model. CONCLUSIONS: The SLS prototype had a greater dimensional accuracy than the PolyJet and 3DP models. The PolyJet technique reproduced anatomic details of the mandible more accurately.

Future stent drug delivery systems.

Drug-eluting stents (DES) with antiproliferative drugs attached via polymers on the stent surface have reduced in-stent restenosis and repeat revascularization compared with bare metal stent (BMS) across nearly all lesion and patient subsets. However, the small number of patients with in-stent restenosis after DES treatment still exists. Furthermore, concerns about long-term safety of DES are raised, particularly regarding the higher-than-expected late-event thrombosis. There is no doubt that the DES will continue to play a pivotal role in the treatment of coronary artery disease, yet future designs need to incorporate features that reduce thrombosis and promote endothelialization along with maintaining the efficacy. This review focuses on novel generation of DES, discussing new programs, including new antiproliferative agents, novel polymeric and non polymeric stents.

Development of a microcontrolled bioinstrumentation system for active control of leg prostheses.

This article describes the design of a microcontrolled bioinstrumentation system for active control of leg prostheses, using 4-channel electromyographic signal (EMG) detection and a single-channel electrogoniometer. The system is part of a control and instrumentation architecture in which a master processor controls the tasks of slave microcontrollers, through a RS-485 interface. Several signal processing methods are integrated in the system, for feature extraction (Recursive Least Squares), feature projection (Self Organizing Maps), and pattern classification (Levenberg-Marquardt Neural Network). The acquisition of EMG signals and additional mechanical information could help improving the precision in the control of leg prostheses.

Study of the different types of actuators and mechanisms for upper limb prostheses.

Research in the area of actuators and mechanisms has shown steadily growing technological advances in externally activated upper limb prostheses. From among the actuators, advances include the use of piezoelectric materials, special metal alloys, polymers, and new motor applications, while the advances in mechanisms include mechanical designs based on the anatomy of the human hand and improvements in the way these components are combined. These efforts are aimed at meeting the need for anthropomorphic and functional prosthetic devices that enable patients to carry out basic daily tasks more easily and reduce the rejection rate of prostheses. This article technically discusses the several types of actuators and mechanisms, listing their main characteristics, applications, and advantages and disadvantages, and the current state of research in the area of rehabilitation of upper limb functions through the use of active prostheses. Comparisons of these devices are made with regard to the main criteria of construction and operation required to achieve optimal prosthetic performance.