Current approaches to cranial surgery are painstaking, requiring a surgeon to use a hand-drill and carefully clear intricate openings in the skull to access the brain. Researchers at the University of Utah say they have come up with a much more efficient way of doing things, developing a robotic drill that could cut operation times by hours and reduce the risk of infection throughout.
The reason why cranial surgery is so meticulous is because of the incredibly sensitive structures spread throughout the human head. Nerves, major veins and arteries all present no-go zones for surgeons carefully carving bone from the skull, which means that the process can take around two hours.
"It was like doing archaeology," said William Couldwell, a neurosurgeon at University of Utah Health. "We had to slowly take away the bone to avoid sensitive structures."
In search of a better way, Couldwell turned to the university's mechanical engineering department and enlisted the help of associate professor AK Balaji to explore the possibilities. He offered us this insight into the process behind the new device.
"Several design considerations needed to be addressed before the drill could be developed," Balaji tells New Atlas. "Of primary importance was the need to develop a safe and reliable device, capable of ensuring repeatability. Also of importance was the need to have a device that could provide access to the surgeon during the surgery. The design team also considered the need for portability of the drill so that it could be easily transported into an operating room. Additionally, use of 3D collated medical image data was incorporated as a design input to enable visualization of the surgical path space."
The result was a computer-driven automatic drill inspired by those used to machine parts for cars. Built from scratch, the drill works with purpose-built software and draws on bone data taken from a CT scan to identify the sensitive structures that must be avoided. Surgeons can then map out a safe path through and program the drill to follow the route, as well as mark safety barriers within 1 mm (0.04 in) of a sensitive structure. Conveniently, the machine removes most of the bone at the same time.
"It's like Monster Garage, except instead of machining a part, we are machining the skull," said Couldwell.
The team put the drill through its paces by having it carve out a translabyrinthine opening on a practice skull, a complicated jigsaw-like cut designed to get around the ear. The team saw this as a suitable proving ground for the drill, as the cut is performed thousands of times a year and must avoid sensitive structures such as facial nerves and large veins, therefore requiring a lot of experience and skill.
The testing was a success, with the team reporting that the exercise demonstrated the safety and speed of the drill, and that it could cut the time of the procedure from two hours to two and a half minutes. This would be a big deal, because shorter surgeries mean less costs, less chance of infection and the automated nature means less chance of human error. It could also boost the chances of a good recovery, according to the team.
What's more, the researchers say the drill could be used in a variety of surgical procedures, such as preparing the bone for a hip implant. They are currently exploring the possibility of commercializing the drill so it is suitably versatile and fit for that purpose.
The video below shows the drill in action, while the research was published online in the journal Neurosurgical Focus.
Source: University of Utah
