University of Basel Researchers Double Laser Bone-Cutting Depth with Novel ‘Top Hat’ Beam Profile

Researchers double the depth of laser bone cuts to 4.5cm using a "top hat" beam profile. Discover how this University of Basel breakthrough impacts surgery.

By: AXL Media

Published: Feb 26, 2026, 6:37 AM EST

Source: The information in this article was sourced from University of Basel

Overcoming the Hard Tissue Barrier

Laser technology has long been considered the ideal surgical tool due to its contact-free precision and ability to create complex geometries. However, its adoption in orthopedics has been stalled by a persistent physical limitation: lasers historically could not cut deep enough or fast enough through dense bone tissue. Existing systems typically lose efficiency at depths of 2 to 3 centimeters, making them unsuitable for major procedures like joint implants. Researchers at the University of Basel’s Department of Biomedical Engineering have now breached this barrier, demonstrating that the primary constraint was not the amount of energy used, but how that energy was distributed within the laser beam.

The Geometry of Energy: Gaussian vs. Top Hat

In a standard laser system, the beam follows a Gaussian distribution, where the intensity is strongest at the center and tapers off toward the edges. While effective for soft tissue, this profile causes the walls of a deep bone cut to absorb a significant portion of the energy, leaving the center too weak to penetrate further. To solve this, the Basel team implemented a "top hat" profile, which caps the central intensity and spreads the energy evenly across the entire surface of the beam. This uniform distribution prevents energy loss to the sidewalls, allowing the laser to maintain its cutting efficiency at depths of up to 4.5 centimeters.

A Breakthrough in Thermal Safety and Healing

Simply increasing the power of a traditional laser to reach greater depths is not a viable surgical solution, as excessive heat can char the bone and permanently damage the surrounding tissue. The top hat profile avoids this "carbonization" by maximizing the photothermal ablation threshold without spiking the temperature at a single central point. Laboratory tests conducted on bovine femur cortical bone confirmed that the new method not only cuts deeper but does so with minimal compositional change to the bone. This preservation of the bone’s biological structure is essential for faster post-surgical healing and the successful integration of implants.