Neurosurgeons Are Practicing on Hollywood Props

No one wants to hear that they're a surgeon's first patient. Especially if it's brain surgery. Especially if the patient is your kid.

But it happens, in part because surgical residents have restrictions on how many hours they can be on duty. Another reason is that the field itself is advancing so quickly—procedures that used to require surgeons to remove a large part of the skull to access areas deep in the brain can now be done with an endoscope, a flexible tube equipped with a light, camera, and other surgical tools, which is inserted through a small hole drilled in the skull.

Endoscopy is better for patients because it's less invasive, which means shorter recovery time and less damage to the brain. But for surgeons, it's a new technique to learn. "The challenge is that the surgery is different—not difficult, but different," says Alan Cohen, the director of pediatric neurosurgery at the Johns Hopkins Hospital. "It's a different eye-hand coordination, it's different skill. We sometimes call it Nintendo neurosurgery because you're only seeing a small part of anatomy at any time and watching a TV screen."

Surgeons are well-trained, of course, and neurosurgeons generally have a seven-year residency. They watch videos of more experienced surgeons doing the procedures, and they practice on cadavers, on physical models, or, increasingly, with virtual reality. But the problem, Cohen says, is that the videos don't give them hands-on training. Cadavers often don't have the specific condition the surgeons are learning to treat. And the models and virtual reality don't provide tactile feedback the way a real human body does.

So to make a better practice dummy, Cohen teamed up with a group of neuroradiologists at Boston Children's Hospital and Hollywood special effects company Fractured FX, which has credits including the grisly Cinemax medical drama The Knick and American Horror Story: Freakshow (for which the company won a Creative Arts Emmy in 2015). Together, the team created a prototype model for trainees to learn how to do a procedure called endoscopic third ventriculostomy, or ETV—it treats hydrocephalus, or water on the brain, one of the most common conditions that pediatric neurosurgeons encounter, Cohen says. (ETV creates a hole in one of the brain's ventricles, or cavities, which allows excess cerebrospinal fluid to circulate.)

Using 3D-printed resins and a variety of different plastics, the special effects artists created a life-size model based on scans from a real hydrocephalus patient. The press release describes it as "uncannily accurate." "Neurosurgeons will buy into something if it looks realistic. If it looks primitive, they will lose interest," Cohen says. The team went back and forth for about a year to make sure the brain had a Jello-like consistency, that the arachnoid membranes had just enough give, and that the basilar artery was sufficiently red and pulsating with the flow of "blood." There is also moving cerebrospinal fluid. You can't get this kind of visual and tactile feedback from virtual reality or cadavers.

The parts of the dummy that the trainees drill through are easily replaceable. The face of the "patient" is eerily lifelike, complete with freckles and eyelashes—so lifelike, in fact, that it fooled the editors of the Journal of Neurosurgery: Pediatrics, where the study was published Tuesday, who asked the study authors to get signed permission from the "patient" in order to run the photo with the paper, Cohen says.

To test their model, the researchers had 17 surgical residents and more experienced surgeons practice on the prototype then complete a questionnaire about how helpful they felt it was. They rated the simulation very high in terms of both tactile feel and how well it mirrored a real ETV. To Cohen, there's only so much you can really get from these questionnaires. The more important test, he says, was having two attending neurosurgeons watch videos of the participants performing the procedure on the dummy and assess how they did. The attendings didn't know whose surgery videos they were watching or which participants had more experience beforehand. But, after watching the videos, they were able to clearly distinguish the trainees from the experts, which is to say that the model is realistic enough to accurately reflect surgeons' years of training.

Video: ETV performed on a patient-specific 3D printed simulator. Copyright Alan R. Cohen., MD.

Cohen is already using the prototype at training conferences. It's not a guarantee that practicing on a more realistic model will translate to better skills in the actual operating room, but he's confident that his team is onto something. "Now that we have this, we will try to refine this model to make it more accurate," Cohen says, first for other conditions that require minimally invasive neurosurgery, and maybe someday for all types of neurosurgery. The brain's components can be swapped out to practice treating a variety of ailments. He says the model could even be used for general surgery. 3D-printed bodies with replaceable parts? This is beginning to sound a lot like Westworld.

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