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SPOT-RVC: A high-precision instrument for ophthalmologists

EPFL scientists have helped develop a microscopic glass device that doctors could use to inject medicine into retinal veins with unprecedented accuracy. Their instrument meets an important need in eye surgery, delivering exceptional stability and precision.

A team of scientists, including EPFL, has developed a breakthrough device called SPOT-RVC that doctors could use to inject medicine into retinal veins with unprecedented accuracy. The device is originally a microscopic glass with a tiny fluidic channel no wider than a strand of hair as well as a sophisticated mechanism of flexible blades.

The SPOT-RVC device which stands for Safe Puncture Optimized Tool for Retinal Vein Cannulation is just 6cm in length and 1 mm in thickness. Scientists developed this device to inject medicine directly into a patient’s retinal veins – something that has never before been possible.

Professor Thomas J. Wolfensberger, the chief physician at Jules-Gonin Hospital, said, “We wanted to develop a surgical method for treating retinal vein occlusion, which occurs when the main vein carrying blood away from the eye is blocked. There is currently no way to treat this condition – we can only treat the resulting complications.”

The high-precision miniaturized medical device, SPOT-RVC © Instant-Lab
The high-precision miniaturized medical device, SPOT-RVC © Instant-Lab

“And those complications can be severe. When a blood clot blocks the retinal vein, this reduces the amount of oxygen carried to the retina and can trigger sudden vision loss. Over 16 million people around the world suffer from this condition, which mostly afflicts the elderly.”

Using the device, scientists could inject blood-clot-dissolving compounds directly into patients’ retinal veins safely, without damaging the surrounding tissue.

As veins are so small, it’s quite challenging to get the needle into the vein without over puncturing. It’s like if you want to drill a hole into a plank of wood but doesn’t want the hole to go all the way through.

The high-precision miniaturized medical device, SPOT-RVC © Instant-Lab
The high-precision miniaturized medical device, SPOT-RVC © Instant-Lab

Dr. Charles Baur, a senior scientist at Instant-Lab, said, “We, therefore, drew on Instant-Lab’s expertise in flexible microstructures and multistable systems to engineering a microscopic device (< 1 mm in diameter) that can transition from one stable state to another very quickly – in around a millisecond – and a controlled manner. With our dynamic perforation mechanism that controls both the penetration force and direction of the needle, retinal veins don’t have time to deform. Also, the penetration force is independent of the force exerted by the surgeon’s hand, which limits the risk of over puncturing.”

Scientists used advanced microfluidics research to develop a tiny fluidic channel of the device to precisely inject the medicine. Moreover, finally, the device is made of a single piece of fused silica (SiO2).

Dr. Baur said, “Since it’s monolithic, there’s no assembly required – a step that would be nearly impossible and would make it very difficult to sterilize the instrument. The monolithic structure was also developed by Galatea and was fabricated by FEMTOprint, using the company’s high-precision 3D printing method and ultra-rapid laser.”

“We got good results from our in vitro and in vivo tests. Now we need to conduct preclinical trials and obtain the necessary certifications. Then we’ll move on to the production stage, which will require a fairly large investment. I genuinely hope that one day, the device will become a useful tool for eye surgeons.”

The device was developed through a joint R&D project involving two EPFL Neuchâtel labs (Instant-Lab and Galatea), the Jules-Gonin Hospital of Ophthalmology in Lausanne and Ticino-based FEMTOprint.

The team’s findings were recently published in the Journal of Medical Devices.

REFERENCEEPFL

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