Conception et développement d'un stimulateur anti-douleur très flexible et complètement programmable

Abstract

The objective of this research project is to design and to implement an advanced full programmable spinal cord stimulation (SCS) system, based on Melzack and Wall gate control theory of pain. The system can be used as a treatment of choice for certain intractable chronic pain not responding to conventional treatment. The system delivers controlled electrical stimuli to some properly selected nerve fibers along the spinal cord. The stimulation of these nerve fibers modulates pain messages being transmitted to the brain. This thesis presents the design and implementation of the basic component of the system, which is the dedicated microprocessor, as well as the other functional parts that have been integrated together to get a miniaturized implantable device provided with appropriate programming and operating tools. The spinal cord stimulation system described here is mainly composed of three parts: two external units and a surgically implanted module. The first external part consists of a computer-based system with completely graphical software and appropriate hardware interface, intended for the physician to program and to adjust the internal part. The patient, in order to control stimulation at his convenience, will use the second external unit. As for the implanted part, this one is built around a powerful mixed-signal ASIC, which is mounted together with appropriate demodulation and power recovery circuits, a memory (EEPROM), and a few peripheral discrete components. Communication of power and data between external and internal parts is achieved through a transdermal inductive link. The system proposed is very user-friendly and unique in its way of operation, providing an unlimited flexibility and complete external programmability. In fact, it is the only miniaturized system providing the user with the possibility to get different stimulation algorithms simultaneously making it more adaptable to the conditions and the state of the patient. It also provides several original features that make it possible to perform a wide range of stimulation algorithms and to generate an unlimited number of stimulus waveforms. As examples, we can mention the possibility of using combined stimuli through simultaneous stimulation over two channels, the possibility of generating complex current pulse shapes, and the access to a greater number of stimulation parameters."--Résumé abrégé par UMI.