Sistemas implantáveis de estimulação elétrica funcional para controle artificial de movimentos funcionais: [revisão] / Implantable functional electrical stimulation systems for artificially controlling functional movements: [review]

Pessoas com lesão no sistema nervoso central (SNC), particularmente após lesão medular e acidente vascularencefálico podem apresentar limitação na capacidade de realização das atividades da vida diária incluindo alocomoção. A estimulação elétrica funcional (FES) promove a contração dos músculos paralisados/paréticos e permite realizar essas tarefas funcionais. O objetivo deste trabalho éapresentar uma revisão dos sistemas artificiais de controle motor implantáveis desenvolvidos para minimizar os efeitos das incapacidades causadas pela lesão e de outras como asdecorrentes de acidente vascular encefálico. Buscas foram feitas no serviço online Google Acadêmico, resultando na compilação de base com 259 artigos. Os estimuladores elétricossão classificados em quatro categorias, dependendo da localização dos eletrodos e da topologia do sistema: externos ou não-invasivos que utilizam eletrodos de superfície, hard-wired implantados com acoplamento transcutâneo, e totalmente implantados. O estimulador elétrico mais antigocitado é de 1961 e o mais recente é de 2008. Os estimuladores elétricos descritos foram eficazes para realizar artificialmente movimentos funcionais. Transdutores de várias naturezas foram empregados em sistemas de malha aberta e fechada. Sistemas de malha fechada tiveram maior incidência nos estimuladores elétricos mais recentes. Estimuladores elétricos totalmente implantados e com acoplamento transcutâneo apresentaram menos problemas com quebras de eletrodos e problemas de infecção do que os hard-wired. As estratégias de estimulação envolveram controle ativado tanto pelo paciente quanto automático. Depósitos de patente também são apresentados. A redução de dispositivos que permanecerão internos a dimensões injetáveis favorece os sistemas de FES com acoplamento transcutâneo. Pesquisas científicas de alta tecnologia buscam desenvolver microestimuladores injetáveis com novos materiais isolantese técnicas de implante menos invasivas...

After suffering a spinal trauma, people with spinal cord injury become unable to perform several daily life activities. The aim of this study is to present a review of artificial motor control systemsdeveloped to minimize the effects of this impairment. A 259-paper database was compiled from the results of queries submitted to Google Scholar online service. Electrical stimulators are classified in four categories according to electrodes placement and systemtopology: external or non-invasive which use surface electrodes, hard-wired, implanted with transcutaneous coupling, and totally implanted. The oldest electrical stimulator cited dates back to 1961 and the most recent is from 2008. The described electrical stimulators were efficient for performing artificial functionalmovements. Transducers of different natures were used in open and closed loop systems. Totally implanted and transcutaneously coupled electrical stimulators showed less electrode failures and infection problems than hard-wired systems. In recent electricalstimulators, closed loop systems are more incident. Patent deposits are also presented. The physical reduction of components and units to injectable dimensions favors transcutaneously coupled electrical stimulators. High technology scientific researches aim to develop injectable micro stimulators with new insulation materials and less invasive implantation techniques. For implantable systems, before performing the implant it is required to test the efficacy and to consider the control strategy practicality. This fact also leads to the need of developing new techniques for communicating more efficiently between implantable electrical stimulators and the external control units.

[A 36 years experience with implantable pacemakers. A historical analysis]. / Experiencia de 36 años con marcapasos implantables. Un análisis histórico.

BACKGROUND: The implantation of pacemakers improves cardiac function and quality of life, in particular with dual chamber DDD and DDDR modes. AIM: To evaluate our clinical experience and results on pacemaker implantation, from 1963 to 1998. MATERIAL AND METHODS: Computerized data collected from 2,445 consecutive paced patients was reviewed. A total of 3,554 operative procedures were performed, including 412 procedures for complications and 697 pacemaker replacement. Patient survival was determined from clinical records, inquiry to pacemaker manufacturers and death certificates from Servicio de Registro Civil e Identificación de Chile (Chilean Civil and Identification Registry). RESULTS: Use of dual chamber (DDD and DDDR) pacemakers increased progressively up to 74% from 1988 to 1998. Complication rate was 42% in the 1963-1976 study period, it decreased to 10.6% in the 1977-1987 study period, and to 5.6% by 1988-1998. Only two patients died during surgery in the study period (0.08%). In the 1977-1987 period, pacemakers lasted 10.6 years. Survival rates were 52% at ten years, 33% at 15 years, and 21% at 20 years, with a median survival of 11.7 years, and 7.24 years in patients over 80 years old. CONCLUSIONS: Transvenous permanent pacing can be accomplished today with a low complication rate, mainly due to better technology and surgical procedures.