Brain surgeons already have a difficult task. Making it harder is the fact that they often can't see exactly what they're doing, sometimes relying on several two-dimensional scans to create a mental image of the inside of a person's head.

Augmented reality can help change that. Surgeons at Duke University are testing the Microsoft HoloLens, the AR headset that's currently in development. The surgeons are using the goggles to project three-dimensional holograms of the brain on the head they're working on.

The first surgery the team is testing, called a ventriculostomy, is used when fluid in the brain is creating dangerous levels of pressure. It entails drilling a hole through the skull and placing the end of a foot-long catheter in the brain.

Normally, a CT scan is taken to produce an image of the brain; the surgeons then use landmarks on the person's head to locate the proper point and angle of insertion. Surgeons are very good at it, but not perfect--and sometimes, the space they're targeting has shifted away from where it usually appears in the brain, so they have to estimate how far from the normal area they need to aim.

Brain surgeons in the operating room use a large, complex computing system called neuronavigation that lets them study the brain in a 3-D space. That system takes time to prepare--a luxury not afforded during an emergency room ventriculostomy.

With the new system, the brain's CT scan can be fed into the HoloLens. That scan is then projected onto the patient's head.

"The idea is that we'll be able to guide the catheter in under navigation, instead of basically doing it blind," says Andrew Cutler, neurosurgery resident at Duke. "We can see the brain how it actually appears, right in front of us in three dimensions."

Cutler and fellow resident Shervin Rahimpour bought their development edition of the HoloLens in the spring. Microsoft is selling the product to testers who can help it develop use cases for the product before its full consumer rollout, which could still be years away.

AR has been tested as a tool for surgery for a while. In 2014, a surgeon at Stanford used Google Glass during a mock surgery to remove a mass from a model human.

Duke's procedure is one of the first to apply to something as intricate as the brain. So far, the team has only tested the HoloLens procedure on models. But Cutler says their goals are to operate on a cadaver by spring of 2017 and to get Institutional Research Board approval to test on people within a year.

Before then, the team will work on getting the hologram to autofuse at the precise location necessary by matching up facial features in the hologram to those of the person. The team will also try to get the catheter to track more accurately.

Check out the team's video below. It's a bit hokey--the catheter tracking clearly needs work, and there most likely wouldn't be a pack of Jolly Ranchers on a real operating table--but it offers a good visual as to how this could someday function.