Title: Minimally Invasive Spinal Cord Stimulator (MI-SCS) for chronic pain treatment
Funder: Department of Health and Social Care

Abstract: Chronic pain represents the leading cause of disability worldwide. Eight million adults in the UK report chronic pain that is disabling, at a &pound;10 billion cost to the UK economy. The proportion of the population experiencing chronic pain is increasing as the population ages. Existing treatments include pharmacological, non-pharmacological and surgical treatments. However, many patients continue to experience pain despite a variety of treatments. Alternative interventions are needed because current therapies are often ineffective. Spinal Cord Stimulation (SCS) is sometimes offered as a treatment for chronic pain, but current technology has several limitations. There are two SCS lead types: cylindrical, inserted percutaneously, and paddle requiring open spine surgery. The former carries little risk but is less effective or stable. Although very effective and stable, the latter carries a much higher risk, especially for frail and vulnerable people. Previous attempts have been made to develop percutaneous paddle electrodes, but these have not demonstrated equal effectiveness and, like cylindrical SCS, have high rates of electrode misplacement. This is because they are just a smaller version of current technology. Our innovation (Minimally Invasive SCS or MI-SCS) implants large paddles through standard Tuohy needles. We have developed a prototype, successfully tested it in in-vitro and human cadaveric spine models, and published our results in a high-impact journal [Science Advances 2021]. MI-SCS is an ultra-thin and flexible electrode, thinner than a human hair. Integrated within it is a set of channels, which can be filled with water or air, allowing a controllable change in the shape of the device (i.e., rolled to unrolled).MI-SCS is inserted with the same technique as a cylindrical SCS but then expands to cover as large a spinal cord area as a paddle SCS. MI-SCS will make available an effective treatment to older and frail patients. It will also increase the capacity of the NHS to deliver effective SCS by simplifying the insertion procedure so that paddle lead placement can be carried out as a simple day-case procedure. The primary aim and key measure of success of this proposal is to achieve the finalized MI-SCS prototype. We will finalize the design and manufacturing process by working with a leading medical device manufacturer. The manufactured prototypes will be tested in human cadaveric models, where the cerebrospinal fluid space has been reconstituted, and in laboratory models of the spinal column. We will demonstrate the long-term stability of the device using proven laboratory techniques. In parallel, we will work with patients and the public and incorporate their feedback across the grant duration. We will work with the University of Cambridge Technology Transfer Office and a Health Economy Agency to strategically plan clinical translation and commercialisation. The department of Clinical Engineering will oversee the regulatory process and interface with the MHRA to prepare for regulatory approval. The complete MI-SCS system will be ready to begin testing for regulatory approvals and first-in-human clinical trials by the end of the project. We intend the device to be in mass manufacture and available for use in five years.

Lay abstract: Chronic pain affects more than one-third of the UK population and is the leading cause of disability in the UK and worldwide. It costs the UK economy &pound;10 billion overall. Many patients require daily opioids for pain control, which can result in dependency and misuse. Opioid prescription is rising and described as the opioid epidemic . Spinal cord stimulation is routinely used in patients whose chronic pain does not respond to non-invasive medical management. Spinal Cord Stimulators (SCS) are devices implanted into the spine that delivers a small electrical current that alters nerve signals in the spinal cord. However, current SCS spinal electrodes have a 5-10% complication rate and can be expensive and difficult to insert. There are currently two different types of SCS: paddle and cylindrical. The paddle is the most effective, but it requires major surgery to implant. Because of the risks, the number of patients suitable for receiving it is very limited. The cylindrical SCS can be implanted through the skin in outpatient settings using a simple needle injection procedure but is less effective and is often displaced, requiring follow-up procedures to reposition it. We have developed a new SCS device that is as effective at reducing pain as the paddle SCS and as safe and easy to implant as the cylinder SCS. We believe it will offer effective relief from chronic pain with minimal side effects and improve patient quality of life. We believe it will make the benefits of effective SCS pain relief available to many more patients. Our device is made possible by using thin, flexible materials, compatible with living tissue, capable of being rolled into a cylindrical-like structure for insertion and then actively unrolled to cover a larger area once inside the body, similar to inflating a rolled-up balloon. The implant is designed to be compatible with standard surgical tools and imaging systems, allowing the clinician to safely and accurately position the implant inside the spinal column in a simple outpatient procedure under local anaesthetic rather than through major spinal surgery. This project will develop our prototype device further. We will finalise the design and manufacturing process by working with a leading medical device manufacturer. The manufactured prototypes will be tested in donated human cadavers (dead bodies) and laboratory models of the spinal column. The finalised prototype will be ready to undergo testing for regulatory approval at the end of the project, including pre-clinical and clinical trials. We hope that a device will be in mass manufacture and available for use within five years.

Research activity codes: 5.3 MEDICAL DEVICES
Health categories: NEUROLOGICAL