Flexible wireless implant offers hope for chronic pain sufferers

Flexible wireless implant offers hope for chronic pain sufferers

Chronic pain is a debilitating condition that greatly impacts quality of life and often leads to opioid medications with their serious side effects and risks of addiction. According to the US Pain Foundation, 51.6 million Americans live with chronic pain. For over 17 million sufferers, their chronic pain is highly impactful - and often limits their life or work activities.

Current implantable electrical stimulators offer an alternative by stimulating the spinal cord to block pain signals from reaching the brain. However, these devices come with drawbacks such as high cost, invasive surgeries, and the need for frequent battery replacement. Now, researchers from the Zhou Laboratory in the USC Viterbi Alfred E. Mann Department of Biomedical Engineering, in collaboration with the Jun Chen group at UCLA, have developed a revolutionary solution: a flexible ultrasound-induced wireless implantable stimulator (UIWI) secured to the back for personalized, self-administering, chronic pain management.

This groundbreaking device, detailed inNature electronicsrepresents a significant leap forward in pain management. While current spinal cord stimulators can be bulky and are hardwired for batteries, the new device is designed to bend and twist with movement and is powered by a portable ultrasound transmitter without the need for a battery. It also uses machine learning algorithms to customize treatment for each patient. The work was led by Zohrab A. Kaprielian Fellow in Engineering Qifa Zhou, who is also a professor of ophthalmology at the Keck School of Medicine of USC.

Pain relief when needed: How the implantable stimulator works

At the heart of this innovation is wireless power, eliminating the need for bulky batteries and complex cable surfaces that often require repeated operations. The UIWI stimulator receives its energy from an external, portable ultrasound transmitter (WUT). Ultrasound offers a safe, effective non-invasive method for deep tissue penetration. The device converts mechanical waves into electrical signals through a phenomenon called the piezoelectric effect. The core of the UIWI stimulator is a miniaturized piezoelectric element made of lead zirconate titanate (PZT), a highly efficient material for converting the electrical energy required for stimulation into electrical power.

What really sets this device apart is its wireless, intelligent, and self-advocating pain management capabilities. We believe it has great potential to replace pharmacological systems and conventional electrical stimulation approaches and address the clinical need for pain reduction. “

Qifa Zhou, Professor of Ophthalmology, Keck School of Medicine of USC

PhD Zhou lab candidate and lead author Yushun (Sean) Zeng said the wireless smart miniaturized stimulator has the ability to generate sufficient electrical stimulation intensity by using ultrasound energy, resulting in personalized, targeted and localized treatment.

“This energy-converting type is crucial for deep stimulation because ultrasound is a non-invasive and highly penetrating energy in clinical and medical fields,” Zeng said. “By leveraging the wireless ultrasonic energy transmitter and closed-loop feedback system, this UIWI stimulator removes the need for bulky implanted batteries and enables real-time, precisely adjustable pain modulation.”

“From a clinical perspective, incorporating deep learning pain assessment enables dynamic interpretation and response to fluctuating pain states, which is essential for adjusting patient-specific variability.” Zhou Lab, Ph.D. Candidate Chen Gong, also senior writer on the paper.

The device works from:

• Schmerzen nachweisen: Das System überwacht die Gehirnaufzeichnungen kontinuierlich, insbesondere Elektroenzephalogramm -Signale (EEG), die die Schmerzniveaus eines Patienten widerspiegeln.
• Nutzung von KI zur Beurteilung von Schmerzniveaus: Ein ausgefeiltes maschinelles Lernmodell, das auf einem neuronalen Netzwerk namens Resnet-18 basiert, analysiert diese Gehirnsignale und klassifiziert Schmerzen in drei unterschiedliche Ebenen: leichte Schmerzen, mäßige Schmerzen und extreme Schmerzen. Dieses KI -Modell hat eine Gesamtgenauigkeit von 94,8% bei der Unterscheidung zwischen diesen Schmerzzuständen.
• Anpassungsbehandlung nach Bedarf: Sobald ein Schmerzniveau identifiziert ist, passt der tragbare Ultraschall -Sender automatisch die überträgende akustische Energie ein. Der UIWI -Stimulator kann dann die vermehrte Energie erfassen und sie in elektrische Intensität umwandeln und das Rückenmark stimulieren. Dies schafft ein System mit geschlossenem Kreislauf, das eine echtzeit personalisierte Schmerzbehandlung bietet.

The UIWI stimulator itself is flexible, bendable and twistable and allows for optimal placement on the spinal cord. The electrical stimulation it delivers to the spinal cord causes the signals that transmit and inhibit pain to be rebalanced, effectively suppressing the feeling of pain.

Proof of success in the laboratory

The Zhou Lab team tested the UIWI stimulator in rodent models, with results demonstrating effectiveness for pain treatment.

Researchers successfully resolved chronic neuropathic pain using mechanical stimuli (such as a pen prick) and acute thermal stimuli (infrared heat).

Laboratory tests showed that treatment with the UIWI stimulator led to significant reductions in pain indicators. In an experiment to evaluate whether an animal associates an environment with pain relief, rodents showed a clear preference for the chamber in which the pain management system was activated, further confirming the effectiveness of the device.

The future of personalized pain relief

The successful development and testing of the UIWI stimulator marks a pivotal moment in the quest for advanced pain management. The implant's flexible design and its integration with sophisticated AI algorithms provides a dynamic and personalized treatment approach that can adapt to the fluctuating and highly individual nature of chronic pain.

Looking to the future, Zhou and his colleagues hope to see even expanded applications of the device. Zhou said future designs could further miniaturize the components and allow for less invasive device implantation - for example, with a syringe. The wearable ultrasound transmitter could also evolve into an unbraked, miniaturized device or even a wearable ultrasound array patch, potentially combining imaging capabilities with energy delivery for real-time monitoring and targeted stimulation. Future iterations could also be controlled by smartphone software, offering even more robust personalized pain management.

Zhou said the device's goal is to transform chronic pain management and go beyond the limitations of current solutions to provide a truly personalized, intelligent and effective way to relieve pain.

“Our results highlight the potential of ultrasound implantable electronics in clinical and translational chronic pain treatment,” said Zeng.

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