The latest study from the University of Cambridge: "Spinal Cord Stimulation" helps you get rid of stubborn pain, thin as hair, without invasive surgery

In the United Kingdom, back pain is the main cause of disability, and the annual cost to the entire economy is as high as 12 billion pounds.

Now, these patients suffering from pain have new hope.

This device is very thin, only about the thickness of a hair, about 60 microns.

Christopher Proctor, one of the corresponding authors of the paper and a PhD in Engineering from the University of Cambridge, said: "Our goal is to create something that has the best of both worlds, that is, medical equipment that is clinically effective but does not require complex and risky surgery.

Early test results of this device show that it can effectively treat many forms of severe pain.

A "best of both worlds" solution

As an effective treatment and relief plan, spinal cord stimulation (SCS) is an option for those suffering from intractable back pain or other types of neuropathic pain.

It is understood that SCS equipment is usually divided into two categories: percutaneous linear probes and paddle probes, which are composed of one-dimensional (1D) and two-dimensional (2D) electrode arrays, but each has its drawbacks: linear probes with a diameter of less than 2 mm It is designed to be implanted percutaneously with Tuohy needles.

The purpose of the researchers at the University of Cambridge is very clear, which is to combine these two devices to develop a minimally invasive paddle SCS (MI-SCS) implant that combines soft robotics manufacturing technology, thin-film electronics technology and microfluidic technology.

The device can be rolled up to fit a needle, allowing percutaneous implantation during low-risk surgery, and then expanded in situ to provide a paddle-type analogue.

Specifically, MI-SCS is designed and manufactured using standard lithography and soft lithography techniques, and the device components in contact with the patient are entirely made of biocompatible materials, including parylene-C, silica gel, and polyethylene , Polyimide and gold

After being rolled up, the device and all packaging, including fluid connections, electrical connections, and support tubes, are designed to be less than 2 mm in diameter.

Researchers can fabricate MI-SCS to a thickness between 30-60μm, where the thickness of the device is determined by the silicone fluid layer, while the electronic layer is only 4μm

Evaluation of performance parameters and implantation methods

After the birth of the laboratory products, the researchers studied the main characteristics of these devices in vitro, including electrical stability, mechanical stability, and dimensional changes after the fluidic components were driven.

The test data shows that using electrical impedance spectroscopy to characterize the electrical characteristics of the MI-SCS device, an electrode yield of 80% has been calculated

The researchers also measured the stability of the device for repeated bending.

Based on the successful in vitro validation, the researchers used a human remains model to test the proposed surgical method for the fully packaged MI-SCS device

In the experiment, the implantation of the device at the L3/4 vertebral body of the human body was carried out by a trained neurosurgeon who was as close as possible to the percutaneous device implantation procedure, that is, through the Tuohy needle, without the need to place the device at the insertion site The laminectomy was performed, and the final implantation effect and process have been initially verified
.

Still needs further optimization

The researchers stated that it is possible to use standard percutaneous procedures to introduce the device into the human body and expand it into a paddle-like structure at a clinically relevant location on the spinal cord
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After deployment, the device is expanded to the size of a common clinical paddle SCS device, with a width of up to 14mm, while providing fewer surgical risks and simple epidural needle insertion procedures
.

It is worth noting that the limitations of X-ray imaging proved to be a challenge for placing thin-film bioelectronic devices under fluoroscopy guidance.
After exploring several technologies and materials to improve the opacity of MI-SCS devices under fluoroscopy, the researchers Finally, a problem-solving strategy was found: the bismuth particles were incorporated into the MI-SCS silicone matrix to create the mark
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The use of this material for patterning can be explored in the future to further help the precise insertion and positioning of the device
.

In practical applications in the future, the robustness, output and functionality of MI-SCS equipment are critical to clinical medical work
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Most equipment failures are due to fluid failures rather than electrical failures.
Since the device requires relatively high pressure to operate in the body, any pinholes or tears in the silicon cavity will cause the device to fail to work properly
.
One of the researchers' goals is to continue to optimize the MI-SCS device design to increase the output and consistency of the equipment
.

Since the relative size of the device is designed for human treatment, it is difficult to scale the device to a very small size suitable for mouse models.
Therefore, it is necessary to use large mammalian models for further experimental verification.
Future work Another goal of the researchers is to conduct in vivo experiments to further prove the safety of this device, to evaluate its effectiveness in treating pain, and to assess the potential risks of accepting this device for a long time
.

However, everything is hopeful
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The principle of the fluid-driven in-situ device that can change its shape can be applied to other stimulation or recording devices, and only needs to rely on low-risk, minimally invasive surgical methods
.
Looking to the future, similar devices can even be implanted in the brain, retina, or in hard-to-reach body parts.
Using this shape-adaptive technology, scientists will be able to place a large area of ​​"electrical interface" throughout the body and realize more derivative solutions.
Bioelectronics and soft robotics technology can also produce implants with unique characteristics, which are expected to revolutionize the current practice of neurosurgery in the medical field
.