The cool blues and icy tundra of SnowWorld help reduce the pain a burn patient experiences by up to 50 percent. Patients can throw virtual snowballs at the penguins or just go along for the ride. ©Hunter Hoffman
In a white, sterilized room in the burn ward of Shriners Hospitals for Children in Galveston, Texas, a physician meticulously removed staples from a teenage boy’s burn. The wound covered more a quarter of his body and would take years of pain therapy to heal. Normally, he would be shouting and squirming with each tug at the bandages, but not that day; his mind was far away from the hospital, immersed in an icy VR tundra called SnowWorld.
For more than 20 years, VR pioneers and pain specialists Hunter Hoffman and David Patterson, both researchers at University of Washington, have demonstrated VR’s unique ability to alleviate acute pain. With the opioid epidemic claiming tens of thousands of lives every year, physicians are increasingly turning to new approaches for the next effective acute painkiller and SnowWorld is one of the most successful examples yet.
Burn patients go through some of the most painful procedures in medicine. A full dose of a prescription opioid like hydromorphone often doesn’t come close to blocking the intense acute pain signals that flood the brain during wound cleanings, staple removal, and physical therapy.
“Acute pain is brief and intense,” Patterson said. “In an evolutionary sense, it’s a way for us to be warned and move into a fight or flight mode.”
A burn patient uses SnowWorld during a wound cleaning. The wide-view goggles, audio headphone, and simple hand controller help keep the patient from focusing on their pain. ©Hunter Hoffman
But during medical procedures, the evolutionary purpose of pain doesn’t do much good. Opioids dull the pain by chemically blocking nerve signals racing towards the brain, but there’s a limit to how much pain they can intercept. The beauty of VR is it doesn’t require any chemicals, just a patient’s full attention. Most of the burn patients Hoffman and Patterson work with are children at the Shriners Hospital with physician Walter Meyer, so limiting their exposure to strong opioids is especially important.
SnowWorld shifts the patient’s concentration away from their pain to an icy, virtual environment bathed in cool blues and whites, where their only task is to throw snowballs at an endlessly advancing group of penguins. It might seem silly, but the results speak for themselves: burn patients experienced 35 to 50 percent less pain when immersed in VR, about the same reduction as a moderate dose of opioid painkillers.
“I think one kid described it best when he said, ‘It’s just white noise,’” Hoffman said. “He said, ‘I wasn’t thinking about anything, I was just shooting snowballs.”
Not only did patients report less pain on the widely accepted subjective pain scale, they also showed about half as much pain-related brain activity while immersed in SnowWorld. After developing a first-of-its-kind, MRI friendly headset over two years, their research team analyzed brain scans of patients with and without VR, showing that pain receptors in the brain are much less active during VR.
Hoffman was surprised during their MRI study when three of their subjects experienced no pain reduction from the prescription opioid but did report large drops in pain when immersed in VR. Burn patients often experience such high levels of acute pain that the researchers combine painkillers and VR to lower pain levels as much as possible. Using VR alone will keep levels the same but also allows patients to avoid taking strong doses of opioids.
“That’s super important because a lot of the patient’s recovery depends on nutrition, sleep, physical therapy exercises, interacting with their family,” Hoffman said. “You don’t want someone to be too medicated because there’s a lot of things we need them to do to get better.”
VR pain reduction, or analgesia, works by acting on that age old platitude “pain is in the mind,” or rather the academic version, “pain requires conscious attention.” Even if the pain signals are firing up a patient’s nerves, the brain can be tricked into ignoring them by focusing brain activity elsewhere.
“If you’re under anesthesia and you’re not conscious, then you don’t feel pain,” Hoffman said. “What we’re doing is making people less conscious using electronics; they’re less in the real world. You’re basically in a tug-of-war between the VR and the pain where the patient is doing the duel.”
With VR and an excruciating wound cleaning vying for the patient’s attention, maximizing pain reduction is all about making the experience as immersive as possible. SnowWorld has only grown more distracting over the last two decades with advances in VR technology.
Pain psychologists and SnowWorld creators David Patterson, left, and Hunter Hoffman. ©University of Washington Photos
Supercomputers the size of refrigerators and eight-pound, $90,000 VR helmets helped kick start the first versions of SnowWorld, but now researchers have incorporated head tracking, wide field of view goggles, and faster graphics processors.
Burn patients are also highly motivated to immerse themselves in the VR because the more they commit, the less pain they feel, creating a positive feedback loop of pain reduction. Back in 2000, the SnowWorld team showed that VR games work a lot better at dulling the pain and reducing anxiety than traditional, console-based games like Nintendo makes.
“You can’t look away from the SnowWorld,” Hoffman said. “What happened with that burn patient was he was supposed to be playing the Nintendo game, but half the time he was actually watching his wound care. With the Nintendo, he’s looking down there saying, ‘be careful! Be careful!’ but with VR he’s like, ‘I want to look down there, but all I see is snow.’”
Patients often experience PTSD and anxiety-driven flashbacks during procedures, which is especially disturbing when most of of their patients are young children. The researchers also worked with former U.S. soldiers who suffered combat-related burns, some of whom suffer from PTSD. Not only does wound care remind these patients of when they got their injuries, it can also elicit negative memories from past procedures, which Patterson believes can often be more traumatizing than they initial burn.
SnowWorld is highly successful in helping patients avoid these painful flashbacks by diverting their attention away from past traumas and into the virtual world. Hardened soldiers reported thoughts of penguins, snowmen, Christmas, and memories of skiing as a child during medical procedures. VR was especially adept in helping children prevent flashbacks.
When patients enter SnowCanyon, they’re greeted by cartoon penguins and snowmen. This software is especially successful with children under 10, but also works well with adults and former soldiers. ©Hunter Hoffman
“It’s not surprising that children embrace VR more, it’s clearly more appropriate for that age level,” Patterson said. “SnowCanyon has a lot of cartoon characters, which is good for children under 10, but for someone in their 40’s we might make something like [a] scuba diving world.”
SnowWorld is currently only being used in research settings at a few hospitals, but the software is available to burn centers across the nation. As VR technology gets cheaper, it’s expected to proliferate in hospitals across the nation and could even make its way into people’s daily health routines. Before long, strapping into a virtual world could be as ubiquitous as taking an aspirin or a novocaine shot at the dentist.