Some cranial operations require two hours of bone removal before work on the tissue below can begin. Inspired by the precision cutting and milling of machine tools, the engineers and neurosurgeons at Utah built a custom device capable of making the same incisions in just two and a half minutes.
"We knew the technology was already available in the machine world, but no one ever applied it to medical applications," said researcher William Couldwell, a neurosurgeon at the University of Utah.
Patients first undergo a CT scan to gather bone data and identify the exact location of nerves and major veins and arteries. This imaging data is then used to program the drill’s cutting path. Surgeons can also input safety barriers along the cutting path to avoid other sensitive structures, and an emergency cut-off switch is tripped automatically if agitation to facial nerves is detected.
The team applied the new drill to the translabyrinthine opening, which is a hard, complex jigsaw-like bone that circumnavigates the ear. It’s a common method of surgery performed thousands of times a year to gain access to slow-growing, benign tumours that form around the auditory nerves. According to the team, the traditional hand-drilling required to make the cut requires advanced levels of skill, and can take in excess of two hours.
"We thought this procedure would be a perfect proof of principle to show the accuracy of this technology," said Couldwell.
By reducing the cutting time to minutes, patients are under anaesthetic for much less time, surgeons are less fatigued, and the chance of infection is significantly reduced. What's more, the device is not restricted to cranial surgery, and could have applications across a range of procedures.
"This drill can be used for a variety of surgeries, like machining the perfect receptacle opening in the bone for a hip implant," said Couldwell.