Children's anti-scoliotic fixators with transcutaneous electronic activation
Conventional spinal implants are static and rigid structures which underpin the skeleton, not adapted to patient's post-surgery evolution (e.g. growth in scoliotic children). A new active spinal implant uses mechanical energy from the patient's body to perform an active, progressive dynamic correction. It is growth-compatible and can be extracted after completion of skeletal amendment. It is non-invasively controlled by means of a transcutaneous transformer. The core of the prosthesis is an internal hydraulic mechanism, which allows the appropriate corrective forces, bending moments and torques to be applied on the spine. The actions of the prosthesis on the skeleton can be periodically modified, under medical supervision, by activating several built-in, remote controlled micro-valves. The power and control signal to transiently activate the intracorporeal microvalves will be obtained by means of a PRC (parallel resonant converter) with a transcutaneous transformer. Telemetry is obtained by adding a slight oscillation in the frequency control circuit, resulting in an AM + FM modulated output signal. This signal is analyzed by a microcontroller in order to activate the selected intracorporeal microvalve The new implant allows a progressive correction thanks to the non-invasive control of its modifiable geometry and its visco-elastic behaviour. (C) 2008 Elsevier Ltd. All rights reserved.
active spinal implants transcutaneous transformer hydraulic circuits transcutaneous signal