ABSTRACT
t a novel miniaturized multi sensor implant for monitoring hemodynamic parameters in cardiovascular regions. Pressure measurements are performed with a highly accurate capacitive pressure sensor. An additional acceleration and temperature sensor allows compensating the impact of patient's inclination and temperature variations on the pressure measurement, respectively. A multi-functional transponder application-specific integrated circuit (ASIC) manages sensor signal processing, storage of ID, sensor calibration data, telemetric energy, and data transmission with an extracorporeal reading unit. Each component of the implant is assembled on a low temperature co-fired ceramics (LTCC) circuit board with an integrated antenna coil enabling an inductive near-field coupling at a frequency of 13.56 MHz. For a streamlined shape and reduction of thrombogenicity, the implant is encapsulated by biocompatible polymers.
Subject(s)
Hemodynamics , Prostheses and Implants , Telemetry , Biocompatible Materials , Cardiovascular System , Equipment Design , Humans , Miniaturization , Pressure , Signal Processing, Computer-Assisted , TemperatureABSTRACT
In blinded patients, visual prostheses can restore visual perception by appropriate electrical stimulation of retinal nerve cells. This article presents the basic technological principles of retinal prostheses, using an epiretinal implantable visual prosthesis as example. An implantable visual prosthesis typically consists of extraocular and intraocular sections. The extraocular section is responsible for detecting the image. The information is derived from this image that is needed for appropriate electrical stimulation of the retinal nerve cells. Together with the necessary energy, these data are transmitted through a magnetic connection to the intraocular section. To ensure reliable transmission, the data are encoded. After transmission, energy and data are separated in the intraocular section, and the data are decoded. In accordance with the transmitted information, biphasic pulses of defined intensity and duration are produced on the simulation electrodes. In this way, ganglia cells are electrically stimulated and react with action potentials, which are transmitted to the visual cortex, where they lead to visual perception.
Subject(s)
Blindness/rehabilitation , Electric Stimulation Therapy/instrumentation , Electrodes, Implanted , Prosthesis Implantation/methods , Signal Processing, Computer-Assisted/instrumentation , Visual Prosthesis , Animals , Blindness/etiology , Electric Stimulation Therapy/methods , Equipment Design , Evidence-Based Medicine , Humans , Prosthesis Implantation/instrumentation , Technology Assessment, Biomedical , Therapy, Computer-Assisted/instrumentation , Therapy, Computer-Assisted/methods , Treatment OutcomeABSTRACT
Massive localized lymphedema is a rare disease. Only a few cases have been described in the literature. These monstrous pseudotumors of the subcutis are mostly localized in the inguinal region or at the lower extremity. These tumors often show a slow growth for many years. Besides hernias, lipomatous tumors must be distinguished. The therapy of choice is the excision of the tumor. Relapse is not uncommon in the few cases described in the literature so far. The diagnostic procedure and therapy of an 48-year-old women with a massive localized lymphedema weighing about 22 kg are demonstrated and discussed.
