Sami Hached

Inductive Power Transfer System With Self-Calibrated Primary Resonant Frequency

Inductive power transfer (IPT) is a commonly employed technique for wirelessly supplying power to implantable medical devices. A major limit of this approach is the sensitivity of the inductive link to coupling factor variations between transmitting and receiving coils. We propose in this paper a new method for compensating these variations and improving the inductive link efficiency. The proposed technique is based on a mechatronic module that dynamically tunes the primary resonant capacitor value in order to maintain the resonance state of the IPT system. The module is able to maintain resonance state for apparent primary inductance range at least from 0.5 to 5 μH using a high capacitance resolution of 0.032 pF. Experimentations conducted on a 13.56MHz IPT system showed a 65% higher power transfer compared to a traditional IPT system.

Novel, Remotely Controlled, Artificial Urinary Sphincter: A Retro-Compatible Device

Implantation of artificial urinary sphincters (AUSs) is considered to be the gold standard treatment in severe cases of stress urinary incontinence. The functioning of these implants is purely hydromechanical, as they apply constant pressure around the bulbous urethra. Common reasons for device revision are insufficient cuff pressure and, in contrast, urethral atrophy secondary to this constant pressure. Furthermore, functioning requires some dexterity, limiting their implantation in some patients. We present in this study a novel electronic AUS that offers the possibility of remotely controlling the sphincter rapidly and without mechanical effort. The implants embedded software can also be updated remotely. Its design eliminates the manual pump, making implantation easier in men and women. Furthermore, it is compatible with already-implanted AUS and can be employed for treating other sphincter deficiencies. The device has been tested on a custom test bed and on pig bladders in vitro. Different occlusive cuff pressure ranges were employed and acceptable performance was obtained. Design challenges and results are reported and discussed here.

Novel, Wirelessly Controlled, and Adaptive Artificial Urinary Sphincter

Severe stress urinary incontinence is a nonnegligible complication that affects men as well as women. When initial therapies are not sufficient, implantation of artificial urinary sphincters (AUS) is considered the gold standard treatment. This hydromechanical device applies constant pressure on the urethra to keep urine inside the bladder. Although recovery from incontinence is full or partial, this approach has certain disadvantages. In addition to the difficulties and discomfort encountered when operating the device, insufficient pressure, urethral atrophy, and erosion from constant pressure on the urethra may necessitate revision surgery. In this study, we present a novel, remote-controlled AUS with variable urethral pressure that improves continence and avoids revision surgery. The proposed design eliminates the manual pump, facilitating implantation in men and women. It is compatible with current AUS. The device requires very little power and its parameters can be monitored and updated post-operatively. It has been tested on pig bladders ex vivo. Different pressure control algorithms have been developed, and expected performances have been achieved. Design challenges and experimentation results are reported.

A Bluetooth-based Low-Energy Qi-compliant battery charger for implantable medical devices

In this paper, we present a smart battery charging system implementing the recently established Qi wireless power transmission standard. Proposed device offers the possibility of charging batteries with any Qi certified power transmitter. It eliminates the dependency to a special charger making energy supplying possible in public places and foreign countries without special equipment or adapters. It is remotely controlled through Bluetooth Low Energy protocol allowing real-time control and supervision with smartphones. The proposed device can be used with single or multiple implants architecture. Experiments have been conducted with various implants prototypes. Proposed charging system ensured proper operation and supervision. System design and experimental results are reported and discussed.

Novel Electromechanic Artificial Urinary Sphincter

Implantation of an artificial urinary sphincter (AUS) is the treatment of choice for managing severe stress urinary incontinence. This hydromechanical implant mimics a healthy sphincter by exerting a constant circumferential pressure around the urethra to close it and keep urine in the bladder. Common complications experienced with this device are urethral atrophy, erosion, and mechanical breakdown. Furthermore, AUS operation requires some dexterity resulting in difficulty and discomfort of use, and limiting the implantation in some patients. We present in this study a novel remote-controlled electromechanic AUS allowing rapid and effortless sphincter operation. Its design eliminates the classic manual pump, enhancing reliability, easing implantation in men and women, and achieving compatibility with already-implanted AUS. The device has been tested in vitro and ex vivo on fresh pig bladders. Different occlusive cuff pressure (OCP) ranges were employed and expected performance was obtained. Experimentation results and design challenges are reported and discussed here in.

Montreal electronic artificial urinary sphincters: Our futuristic alternatives to the AMS800™

INTRODUCTION We aimed to present three novel remotely controlled hydromechanical artificial urinary sphincters (AUSs) and report their in-vitro and ex-vivo results. METHODS We successively developed three distinct hydromechanical AUSs on the basis of the existing AMS800™ device by incorporating an electronic pump. No changes were made to the cuff and balloon. The AUS#1 was designed as an electromagnetically controlled device. The AUS#2 and AUS#3 were conceived as Bluetooth 2.1 remotely controlled and Bluetooth 4.0 remotely-controlled, adaptive devices, respectively. In-vitro experiments profiled occlusive cuff pressure (OCP) during a complete device cycle, with different predetermined OCP. Ex-vivo experiments were performed on a fresh pig bladder with 4 cm cuff placed around the urethra. Leak point pressure with different predetermined OCP values was successively measured during cystometry via a catheter at the bladder dome. RESULTS Our in-vitro and ex-vivo experiments demonstrated that these three novel AUSs provided stable and predetermined OCP - within the physiological range - and completely deflated the cuff, when required, in a limited time compatible with physiological voiding cycles. CONCLUSIONS Our three novel, remotely controlled AUSs showed promising results that should be confirmed by in-vivo experiments focusing on efficacy and safety.

Stability of GaN150-based HEMT in high temperature up to 400°C

The first high-temperature characterization of GaN150 HEMT devices is presented from ambient temperature to 400°C. With a 2-gate length of 150nm, three configurations of GaN150 are investigated. They have gate widths of 40µm (T<inf>1</inf>), 100µm (T<inf>2</inf>) and 200µm (T<inf>3</inf>) respectively. The stability with temperature of the electrical characteristics of the AlGaN/GaN devices are measured with tungsten probes while the tested die is heated by a hot plate. The packaging is a standard tungsten based metallization, with Ni and Au plating, supporting a 92% alumina ceramic substrate. The drain saturation current decreases from 50mA, 150mA and 290mA at room temperature (RT) to 35mA, 110mA and 175mA at 400°C for T<inf>1</inf>, T<inf>2</inf> and T<inf>3</inf> respectively. The peak transconductance value of T<inf>1</inf> is dropped from 22mS at ambient temperature to 8mS at 250°C. The pinch-off voltage is stable at VGS = −5V during the whole temperature change.

Smart artificial urinary sphincters: Implementation challenges

Stress urinary incontinence is a complication that considerably affects patient quality of life. When conservative measures are not sufficient for recovering patients continence, urologists suggest the implantation of an artificial urinary sphincter (AUS). The AMS 800 has been the gold standard AUS for more than 35 years now. This hydro mechanical device mimics the behavior of a healthy sphincter. However, it suffers from several limitations reported by medical studies and follow up. In this paper, we present our concept of the smart AUS. The latter corrects the limitations and extends the capabilities of current AUSs. We report here-in three different versions of the smart AUS. Each version integrates novel capabilities and unique features. Each device is presented and its experimentation results are detailed. Design challenges are discussed and technological barriers for the further development of actual AUSs are explained.