Companies dealing with profound hearing loss, chronic pain, Parkinson's disease, and epilepsy must rely on expensive and technologically-limited hand-assembled electrode arrays in their neurostimulators. These devices are costly due to low throughput and yield; the complexity is limited by what can be achieved with the human hand; and quality assurance is difficult to maintain in the presence of human error. By using lithographically-based technology for the automated manufacturing of arrays, this project has the potential to significantly reduce their cost while improving their reproducibility and performance. The microelectromechanical arrays has the potential to enable medical device manufacturers to increase the number of electrodes on their leads by 5X, reduce the size of the electrodes by greater than 30X, reduce the overall size of the leads by 92%, and easily define the mechanical properties of the arrays. And by utilizing this technology to eventually add position sensing and actuation, the team believes that the insertion of the arrays can be largely automated, reducing surgical placement time and cost while allowing better placement and improved performance.
There is a rise in the incidence of neurological diseases and disorders in the US. Conditions such as hearing loss, Parkinson's disease, and epilepsy are more prevalent now than ever, and pharmaceutical solutions are lacking in both effectiveness and safety. Neurostimulation implants have been developed to treat such conditions, however, their performance and costs are lacking, due to hand-assembly manufacturing. In the case of hearing loss, over 150,000 cochlear prosthetics have been implanted worldwide to date; however, over 250 million people worldwide are estimated to be disabled due to hearing loss. Many of these people are in developing countries and lack the funds necessary to take advantage of current prostheses, both due to the cost of the systems themselves and due to the cost of the associated surgery. By using lithographically-based technology for the neurostimulation arrays, the team has the potential to significantly reduce their cost while improving their surgical safety and performance. The enabling technology will also promote the creation of new neurostimulation devices (e.g., for blindness and paralysis) whose size and complexity is not currently achievable with hand-assembly. The technology being proposed promised to result in a significant leap forward in the practical treatment of neurological disorders and diseases on a worldwide scale and thus possesses the potential for significant impact.
Over 150,000 cochlear prostheses have been implanted worldwide to date. They have been remarkably successful, but over 250 million people worldwide are estimated to be disabled due to hearing loss. Many of these people are in developing countries and lack the funds necessary to take advantage of current prostheses, both due to the cost of the systems themselves and due to the cost of the associated surgery. We hope to dramatically reduce cost in both areas by replacing the current hand-assembled wire-bundle electrode arrays with thin-film arrays fabricated using Micro Electro Mechanical Systems (MEMS) technology. Free of the size constraints associated with wire arrays, it should be possible to significantly increase the number of electrodes (improving pitch specificity) and insert the arrays more deeply (and more safely) into the cochlea (achieving greater pitch range). And by utilizing this technology to add position sensing and actuation, the insertion of the arrays can eventually be automated, reducing surgical placement time and cost while preserving more residual hearing. Many of these benefits extend well beyond the cochlear implant market and could also be used to treat conditions such as chronic pain, epilepsy, Parkinson’s disease, blindness, and other disorders. In this grant we investigated the commercial opportunities for MEMS array technology in the clinical marketplace. We did this in two ways: 1) We surveyed 84 potential customers in the cochlear, spinal cord, facial paralysis, deep brain and vagus nerve stimulator markets; 2) We tested fabrication methods for incorporating clinically viable materials into pre-existing MEMS cochlear array designs. Our first hypothesis was that the primary advantage of MEMS electrode arrays over hand-assembled cochlear implants is that the MEMS fabrication technology can pack an order-of-magnitude more electrodes in the same space as the wire bundle arrays. After surveying clinicians from leading implant centers, leading cochlear implant manufacturers, and cochlear implant recipients, we discovered that this hypothesis was incorrect. Many customers interviewed were skeptical that increasing the number of electrodes would actually improve performance. In fact, some even saw more electrodes as a disadvantage. However, many mentioned the need for smaller, more flexible arrays capable of better preserving residual hearing. The manufacturers agreed that hand manufacturing techniques limit how small the present arrays can be made, compromising the residual hearing a patient may have. This is very important because preserving residual hearing improves sound recognition and could open a significantly expanded portion of the hearing-impaired population to cochlear implants. At the conclusion of the survey, we determined that for cochlear implants the primary advantage is that because of smaller array size MEMS technology can be inserted more easily and with less damage to residual hearing. Our second commercialization hypothesis was that demand exists in non-cochlear neurostimulator markets. After surveying customers in the spinal cord stimulation, deep brain stimulation and facial paralysis stimulation communities, we determined that this hypothesis is true. Spinal cord and deep brain stimulator manufacturers are currently funding internal research to produce MEMS arrays for these prostheses and are actively seeking relationships with startups in MEMS array development. Despite the need for MEMS technology in these markets, our third hypothesis was that cochlear implant manufacturers are the best initial target. To test this hypothesis, we developed a customer archetype from interviews with business development and technology leaders in all three markets (spinal cord, deep brain, and cochlear), estimated manufacturing costs for each market, and assessed the cost savings in each market that could be expected by switching to MEMS arrays. After all analyses were completed, we determined that cochlear implants are indeed the best initial market. This area is the most eager to adopt the technology, has the greatest need to reduce hand-assembly manufacturing complexities, and could receive the greatest cost savings by switching to a MEMS-manufactured array. Our final hypothesis was that MEMS fabrication steps can be used to produce arrays using medically-approved materials (platinum and silicone) that are suitable for long-term in-vivo use. Both materials are attractive mechanically and are biocompatible but are difficult to etch and deposit using standard MEMS processing. To test this hypothesis we developed processes to deposit and selectively etch platinum and silicone layers on silicon carrier wafers. We were able to build low-stress electroplated platinum stimulating sites on lithographically-defined platinum seed layers and to pattern silicone array substrates using reactive ion etching (RIE). Based on the conclusions reached in testing all four hypotheses, we determined it is feasible for MEMS cochlear electrode arrays to be produced and sold through a startup entity based on the ability to preserve residual hearing. We estimate that there is a revenue opportunity between $152M/yr and $358M/yr for a startup in this area within five years, making cochlear implants available to a greatly expanded portion of the hearing impaired population.
