Applying an energy source, such as a laser, to cut through or cauterize tissue is already widely used in external surgeries, such as laser eye surgery, but using this technology safely and accurately during minimally invasive internal procedures is difficult. Current endoscopic technology does not permit lasers to be steered and manipulated with sufficient precision.
Now researchers at the Harvard Wyss Institute have developed a new technique to accurately steer a laser beam at the end of an endoscope for minimally invasive laser surgery. The approach relies on three small mirrors that move within a tiny cylinder to accurately steer the laser path within a significant range of motion. The entire device resides within the working channel of an endoscope, allowing a surgeon to precisely control laser movement inside the body.
“To enable minimally invasive laser surgery inside the body, we devised a microrobotic approach that allows us to precisely direct a laser beam at small target sites in complex patterns within an anatomical area of interest,” said Peter York, a researcher involved in the study. “With its large range of articulation, minimal footprint, and fast and precise action, this laser-steering end-effector has great potential to enhance surgical capabilities simply by being added to existing endoscopic devices in a plug-and-play fashion.”
The system uses a series of small mirrors that can be articulated to control the path of the laser through the device, which it enters through an optical fiber. The major challenge was creating a working mechanism within such a small space – the cylinder used to house the components is approximately the diameter of a drinking straw.
“We found that for steering and re-directing the laser beam, a configuration of three small mirrors that can rapidly rotate with respect to one another in a small ‘galvanometer’ design provided a sweet spot for our miniaturization effort,” said Rut Peña, another researcher involved in the project. “To get there, we leveraged methods from our microfabrication arsenal in which modular components are laminated step-wise onto a superstructure on the millimeter scale – a highly effective fabrication process when it comes to iterating on designs quickly in search of an optimum, and delivering a robust strategy for mass-manufacturing a successful product.”