The piercing whine of a drill fills the room as the brain surgery begins.
Beneath bright surgical lights, the surgeon makes small holes so that he can remove a small portion of the skull – a common and usually uneventful step in one of the most sensitive procedures in medicine. So far, so good. Setting aside the drill, the surgeon picks up a small tool, called a curette, to pry the piece up and gain access to the brain itself.
Suddenly, blood begins spurting out of the breach.
The surgeon has nicked a large vein enclosed within the dural covering of the brain. Known as a venous sinus, this vein carries as much as 15 percent of the heart’s entire output. As alarms sound on monitors, the surgeon has only seconds to assess the situation and save the patient’s life. He covers the injury with sterile gauze while applying pressure to stem the bleeding. As he begins to craft a surgical repair to the vessel, another catastrophe occurs: air is being sucked through the vent and down into the patient’s heart. The surgeon quickly calls for the gurney to be lowered to prevent more air from leaking in. Finally, he peels away a thin layer of adjoining dura membrane, folds it over the cut in the vein and seals the repair with stitches.
“Great job,” says Nathan Selden, M.D., Ph.D.
Selden, Campagna Professor and chair of neurological surgery at OHSU, watched the entire procedure with a hands-off approach. In fact, the scenario was real, but the patient was not – and that’s exactly the point of the new brain surgery simulator developed at OHSU. In this case, first-year neurosurgery resident Stephen Bowden, M.D., gained invaluable experience without risking the life of a flesh-and-blood patient.
The simulator model included a brain, skull and dural membrane produced using a 3-D printer, rigged to a bag containing mock blood. The entire program was controlled by a computer program that also displayed simulated life signs on real patient monitors and recorded the resident surgeon’s every move.
Selden compares the concept to a flight simulator used by pilots in training. Just like pilots, neurosurgeons need to diagnose problems, make complex decisions and perform technical tasks flawlessly – all at the same time - during periods of high stress. In both cases, a simulator enables trainees to avoid learning through trial and error, without risk to actual patients or passengers.
Selden developed this training technique for the neurosurgery “boot camp” courses held every year for all beginning neurosurgery trainees across the country. Recently, Selden and his team validated this approach and published their findings in the Journal of Neurosurgery. As part of the study, the team measured the heart rate of 11 resident neurosurgeons along with one experienced attending surgeon who each went through the simulation. Although the attending physician’s heart rate was demonstrably lower during the exercise, the study confirmed the simulator is a heart-pounding experience for everyone.
Bowden can attest to that.
“There was red fluid coming out of somebody’s brain, so, yeah, it was real,” he said. “The beeping sends a chill down your spine.”
This marks the first year the Society of Neurological Surgeons has required all junior neurosurgery residents to use a simulator as part of their training. Selden, who was elected this year as secretary for the society, was also the founding national director of the organization’s resident boot camp courses.
The simulator now is integral to preparing neurosurgeons nationwide.
“What you really need is experience and focus,” Selden said. “The more you’ve seen and done, the better your patient is going to do.”
Two OHSU medical residents, Dominic Siler, M.D., Ph.D., and Daniel Cleary, M.D., Ph.D., worked under Selden’s guidance to design the simulator hardware and software. Both have gone on to neurosurgical residency training, Siler at OHSU and Cleary at the University of California-San Diego. Siler said he and Cleary took up Selden’s challenge to design a simulator that’s as real as possible. They both wanted to create a model that would improve on their own experiences training with cadavers.
“Cadavers will always be great for anatomy, but they don’t bleed and can’t die if you make mistakes, so no one is stressed out about that,” Siler said.
Selden said they got it right.
“They far surpassed my expectations,” he said. “Everything seems amazingly real, from the setting, to the model, to the experience itself.”
Siler and Selden say they expect the intense vibe experienced in training will increasingly translate into positive outcomes for patients. Selden believes that in the two years since the simulator has been used, it has likely already saved lives because new surgeons are already accustomed to working under pressure.
“We want people to fail, because that’s how they learn,” Selden said. “The problem is, historically patients have paid the price.”
With the new simulator, failure means learning, and learning means safety and recovery for the real patients to come.