A NOVEL ACTIVE ELECTRODE BOOK FOR MULTI-FUNCTIONAL RESTORATION AFTER SPINAL CORD INJURY
Lead Research Organisation:
University College London
Department Name: Electronic and Electrical Engineering
Abstract
It has been shown that electrical stimulation of the lumbar and sacral anterior and posterior nerve roots in the spinal canal can restore many functions to people with serious spinal cord injury, to improve their health and quality of life. This requires the use of many stimulating electrodes. However, a major concern in implanted nerve root stimulators for chronic use with patients is safety. Electrodes that are meant for stimulation could, under fault conditions, corrode or electrolyse water in the tissue causing nerve damage. This danger is usually diminished and made acceptable by placing a large blocking capacitor (in the uF range) in series with each stimulating electrode. These capacitors determine the physical size of the stimulator which is too large to fit in the spinal canal. Thus, existing implanted devices have a subcutaneous stimulator connected with cables to the intra-thecal nerve root electrodes. Surgeons consider that it is an unacceptable surgical risk to increase the number of cables which pass through the dura, and this limits the number of functions that can be obtained. This is a serious disadvantage given the number of valuable functions that have been shown to be possible. One way to overcome this limitation is to generate the stimulation currents close to the electrodes, inside the dura, but that means that the size of the electronic package must be very small and yet it must still be safe. We have invented a method which allows us to use blocking capacitors as small as 50pF, so that the complete stimulator can be integrated on a single silicon chip, and still be fail-safe. In this research, we propose to develop the technology in the form of an active electrode book that may be directly implanted in the human spinal canal for multi-functional restoration after spinal cord injury. In addition, we will develop new minimal integrated circuit sealing methods for use in small implanted devices, and a new micro-fabrication method to cut the platinum electrodes out of foil with a laser and join them to the stimulator chip. Prototype active electrode books will be produced that will be made available for subsequent pilot studies in patients. The project is a multidisciplinary collaboration between University College London, the Tyndall National Institute in Ireland, and the University of Freiburg in Germany.
Publications
Cirmirakis D
(2013)
Humidity-to-Frequency Sensor in CMOS Technology With Wireless Readout
in IEEE Sensors Journal
Cirmirakis D
(2011)
An implantable humidity-to-frequency sensor in CMOS technology
Demosthenous A
(2013)
An Integrated Amplifier With Passive Neutralization of Myoelectric Interference From Neural Recording Tripoles
in IEEE Sensors Journal
Flynn M
(2010)
Characterization and Mechanical Reliability Evaluation of Gold Polysilicon Eutectic Bonded Wafers
in ECS Transactions
Jiang D
(2018)
A Multichannel High-Frequency Power-Isolated Neural Stimulator With Crosstalk Reduction.
in IEEE transactions on biomedical circuits and systems
Jiang D
(2017)
An Integrated Passive Phase-Shift Keying Modulator for Biomedical Implants With Power Telemetry Over a Single Inductive Link.
in IEEE transactions on biomedical circuits and systems
Langlois PJ
(2010)
High-power integrated stimulator output stages with floating discharge over a wide voltage range for nerve stimulation.
in IEEE transactions on biomedical circuits and systems
Liu X
(2011)
An Integrated Stimulator With DC-Isolation and Fine Current Control for Implanted Nerve Tripoles
in IEEE Journal of Solid-State Circuits
Liu X
(2012)
Active books: the design of an implantable stimulator that minimizes cable count using integrated circuits very close to electrodes.
in IEEE transactions on biomedical circuits and systems
Liu X
(2016)
An Implantable Stimulator With Safety Sensors in Standard CMOS Process for Active Books
in IEEE Sensors Journal
Liu X
(2016)
Advances in Scalable Implantable Systems for Neurostimulation Using Networked ASICs
in IEEE Design & Test
Liu X
(2008)
Platinum electrode noise in the ENG spectrum
in Medical & Biological Engineering & Computing
Nonclercq A
(2012)
Safety of multi-channel stimulation implants: a single blocking capacitor per channel is not sufficient after single-fault failure.
in Medical & biological engineering & computing
Saeidi N
(2010)
Developing a Wafer Level Gold-Polysilicon Eutectic Bond Process to Protect Sensitive Electronic Devices
in ECS Transactions
Saeidi N
(2013)
A Capacitive Humidity Sensor Suitable for CMOS Integration
in IEEE Sensors Journal
Saeidi N
(2013)
Technology for integrated circuit micropackages for neural interfaces, based on gold-silicon wafer bonding
in Journal of Micromechanics and Microengineering
Saeidi N.
(2009)
Design and fabrication of corrosion and humidity sensors for performance evaluation of chip scale hermetic packages for biomedical implantable devices
in 2009 European Microelectronics and Packaging Conference, EMPC 2009
Xiao Liu
(2008)
An Integrated Implantable Stimulator That is Fail-Safe Without Off-Chip Blocking-Capacitors.
in IEEE transactions on biomedical circuits and systems
Description | Developed new implantable stimulator technology. |
Exploitation Route | We expect the technology to be used in the development of future implantable stimulators. |
Sectors | Electronics,Healthcare |
Description | European Commission - FP7 |
Amount | € 1,168,134 (EUR) |
Funding ID | 258654 - NEUWalk |
Organisation | European Commission |
Sector | Public |
Country | European Union (EU) |
Start | 06/2010 |
End | 11/2014 |
Description | Tyndall National Institute |
Organisation | University College Cork |
Department | Tyndall National Institute |
Country | Ireland |
Sector | Academic/University |
PI Contribution | We provided expertise in the development of microelectronics for implantable stimulators. |
Collaborator Contribution | They provided expertise in the development of micropackages for implantable devices. |
Impact | Several joint publications as listed in the outputs. |
Start Year | 2007 |