Scientists in Scotland have shown that a laser technology long used in eye surgery can slice soft tissue with extreme precision, hinting at future brain operations that remove tumors cell by cell while sparing healthy tissue.
A laser technology that has reshaped millions of corneas could one day help neurosurgeons remove brain tumors with far greater precision, according to new research from Heriot-Watt University and the University of Edinburgh.
In one of the most detailed studies yet of how deep-ultraviolet, ultrashort-pulsed lasers interact with soft biological tissue, the team showed that the same type of laser used in common eye procedures can remove tissue in slices as thin as 10 micrometers. That is far finer than the millimeter-scale precision currently possible in brain surgery.
The work, part of the multidisciplinary u-Care project funded by the Engineering and Physical Sciences Research Council, part of UK Research and Innovation (UKRI), is published in the journal Biomedical Optics Express.
For about 30 years, surgeons have used ultraviolet lasers in procedures such as LASIK to reshape the cornea, the clear front surface of the eye. In those operations, tightly controlled pulses of UV light remove microscopic layers of tissue while leaving surrounding areas largely untouched.
The cornea is an ideal target.
“The cornea is well suited to this technique because it is rigid, collagen-rich and the eye’s surface is easy to reach with an ultraviolet laser beam,” Tatiana Malikova, a doctoral student in Heriot-Watt’s School of Engineering and Physical Sciences who led the study, said in a news release.
Soft tissues deeper in the body, such as the brain, are a much tougher challenge. They are mechanically weaker, more fragile and harder to access. Until now, there have been very few systematic studies of how deep-ultraviolet, ultrafast laser pulses behave in these kinds of tissues.
To tackle that gap, Malikova and her colleagues turned to an unusual stand-in for the human brain: lamb liver from the supermarket.
Lamb liver is soft and mechanically weak, though not as delicate as actual brain tissue. Crucially, it is easy to obtain in large quantities, which allowed the researchers to run hundreds of tightly controlled experiments and build a detailed picture of how the laser interacts with challenging soft tissue.
Using a deep-ultraviolet laser system that emits pulses lasting just femtoseconds (quadrillionths of a second), the team achieved clean, controlled removal of tissue with an axial precision of about 10 micrometers. Under the right conditions, microscopic analysis showed no detectable damage to tissue surrounding the ablation zone.
That level of control matters because in neurosurgery, even tiny errors can have life-changing consequences. Surgeons already operate with great care and skill, but they are constrained by the physical limits of their tools and by what they can see and feel in the operating room.
Malikova contrasted current practice with what the laser could eventually offer. Neurosurgeons are very precise, but their precision is on the millimetre scale. Getting to 10 micrometres, which is 10 times finer than a human hair, is not realistic with current tools.
In the new study, the researchers combined careful control of the laser parameters with extensive histology, the microscopic examination of tissue slices. That allowed them to document in detail how different laser settings affected both the targeted area and the surrounding tissue.
Their findings suggest that, with the right laser wavelength, pulse duration and energy, it is possible to remove extremely thin layers of soft tissue while leaving neighboring cells intact. In principle, that could allow surgeons in the future to shave away tumor cells at the edge of a growth while preserving healthy brain tissue just a few cells away.
The work is still at an early, experimental stage. The team used animal tissue models, not living human brains, and the laser system itself is a specialized laboratory setup. Any move toward clinical use would require years of further research, engineering and safety testing.
Still, the potential impact is drawing attention from clinicians.
Co-author Paul Brennan, a professor of clinical and experimental neurosurgery and honorary consultant neurosurgeon at the University of Edinburgh’s Centre for Clinical Brain Sciences, has been advising the u-Care team on possible applications in brain surgery.
“The ultrafast laser approach promises a level of precision that could transform the way we treat intracranial tumours,” Brennan said in the news release.
In neurosurgery, a few millimeters can separate a good recovery from permanent disability. Tools that can reliably work at the scale of tens of micrometers — about one-tenth the width of a human hair — could change how surgeons think about removing tumors that sit close to critical brain regions.
The u-Care project is focused on making that vision more realistic by pushing the underlying laser technology forward. The team aims to develop deep-ultraviolet light sources that are compact and robust enough for clinical environments, and to design precise ways to deliver that light safely into the body.
If successful, the benefits could extend beyond brain surgery. Deep-ultraviolet lasers interact strongly with many biological molecules, which opens possibilities for highly selective cutting or sterilization. Researchers involved in u-Care hope that, in the long term, the same platform could support cancer surgery with cellular-level precision and new strategies to combat drug-resistant superbugs.
Co-auhor Robert Thomson, a professor of photonics in the Institute of Photonics and Quantum Sciences at Heriot-Watt and primary investigator on u-Care, emphasized the long-term promise.
“Within the next few decades, laser technologies like this could transform surgery and improve patient outcomes,” he said.
Realizing that promise will require more than just better lasers. Malikova and her colleagues envision a future in which advanced imaging and robotic guidance systems are standard in operating rooms. High-resolution brain scans could map a tumor and nearby critical structures in three dimensions, while robotic arms position and steer the laser with sub-millimeter accuracy.
In that kind of setting, a deep-ultraviolet ultrafast laser could become one part of an integrated surgical platform, capable of removing diseased tissue layer by layer while surgeons monitor progress in real time.
For now, the lamb liver experiments mark a key step: showing that a tool proven in eye surgery can, under carefully controlled conditions, slice soft tissue with extraordinary precision and minimal collateral damage. It is an early but important sign that the same physics that sharpened vision for millions of patients might one day help neurosurgeons operate at the level of individual cell layers, giving more people a chance at safer, more effective brain surgery.
Source: Heriot-Watt University