VR for Back Pain!

Isn’t the future amazing. Just think how excited Mark Zuckerberg was to see that the Metaverse could treat real ailments.

But let’s back up. 

By ESA, CC BY-SA 3.0 igo, https://commons.wikimedia.org/w/index.php?curid=62840930

But before that

I work professionally as a Physical Therapist and Strength Coach. If you are interested in my services you can contact me at: hirsch.sm@gmail.com or thru Trainerize.

FDA Regulation

If I survey a bunch of folks I expect that most would agree that we want the FDA to regulate medical “stuff” for the following things:

  • Efficacy – does it actually treat the condition
  • Safety – does it hurt you
    • And what side effects does it have
  • Content – does the product actually contain what it says
  • Purity – does it NOT contain other stuff

(Except for Libertarians they’d disagree with the whole premise because the “market” will sort it out better than the Government. But recorded history shows them to be factually incorrect.)

And what medical “stuff” do folks want regulated this way? Well, again, I suspect that most folks would want this list of stuff covered:

  1. Pharmaceuticals i.e. what’s usually meant by drugs in this context
  2. Homeopathic preparations*
  3. Natural and herbal remedies*
  4. Medical devices
  5. Surgical procedures
  6. Other medical treatments not covered by the above. 

* Sellers of homeopathy and herbal remedies would claim that FDA regulation is unnecessary because they “know” it’s safe and effective etc.

So what on that list is regulated by the FDA the way most folks want it to be? Item #1 only. That’s it. Formally #2 is also but the FDA only recently started to and they still devote minimal resources to it. 

Medical Devices

Leaving aside the lack of FDA regulation for safety and efficacy of surgery or the things that PT’s like myself do, let’s talk about medical devices. 

The FDA does not “approve” medical devices. They authorize them. This is a key distinction in their lingo. Approve means that it’s tested for all the characteristics at top. Authorized means the device is safe and it may even work. They apply a lower standard of evidence for what works. 

Drugs require multiple double-blind studies showing a clinically significant effect size. As well as a good balance of adverse events and side effects against the dangers of the condition being treated. 

Devices need to be safe. So an e-stim or TENS device for relief of chronic low back pain must only shock you in the specific way that it is intended to do and not randomly shock you in a way that causes injury. They are regulated for content in the sense that the TENS unit has to actually deliver electricity. And for purity in the sense that it can’t be secretly a drug delivery method. 

Now e-stim actually works for temporary relief of back pain and is appropriate in very limited cases. I’m not knocking on the authorization for it. But it is not approved and not subjected to the same level of testing as pharmaceuticals.

On to the Metaverse!

The FDA authorized marketing for a VR program to treat chronic low back pain. Note a key word in there: marketing. The FDA auth is for selling and advertising. It is not for FDA approval. While the company is likely to tout the “FDA AUTHORIZATION” all over it’s marketing, without breaking any rules, you can safely bet that third party promoters will muddy the waters by saying “approved”. 

The FDA’s own description of the single study of this product’s efficacy leaves a lot to be desired. Such as evidence that it works.

They tout percent decreases in pain such as 30% and 50% and for how long those effects lasted. The numbers look impressive. But pain relief is not normally reported that way in the literature I’m familiar with. 

Pain relief is normally reported the way the next paragraph reports it.

“To evaluate the effectiveness of EaseVRx, at the end of the eight-week program, participants were asked to rate the following outcomes on a 10-point scale, with 10 being the greatest value: pain intensity, pain interference on activity, pain interference on mood, pain interference on sleep and pain interference on stress. On average, participants experienced a decrease in pain intensity of 1.31 points over the eight weeks of treatment. Participants also reported a decrease in pain interference for all measured outcomes that ranged from .95 points to 1.27 points down from their respective scores at the start of treatment.”

https://www.fda.gov/news-events/press-announcements/fda-authorizes-marketing-virtual-reality-system-chronic-pain-reduction

But those results are not clinically significant. It is standard for me to ask patients to rate their pain on a scale from 0 to 10. It is normal for them to reply with two numbers, such as “1 or 2” or “5 or 6”. Humans don’t really differentiate pain on an 11 point scale. A five or six point scale is probably closer to our actual precision. 

This is formally known as Minimum Detectable Change (MDC). Imagine that two businesses are selling sticks of various lengths. And one business claims that, on average, their sticks are 1/4” longer than the competitors. BUT it turns out they did their measurements with a yardstick that was only marked in 1 inch increments, with none of the smaller lines between inches. Would you still trust their claim to be 1/4” longer?

No, you wouldn’t trust the claim. Their instrument for measuring lacks the precision necessary to make that claim. Well, we have just that data for the Numeric Pain Rating Scale (NPRS) – and it’s the same for the Visual Analog Scale (VAS) (just multiply by 10). That data shows a MDC of about 1.5. So any result below 1.5 cannot be trusted as a real difference. 

But I said clinically significant. This term refers to whether or not the difference matters to the patient and clinical outcomes. We measure this characteristic in part with Global Rating of Change (GRC). As well as other methodologies. And from this we generate a Minimum Clinically Important Difference (MCID). The MCID for that pain scale is about the same as the MDC, which isn’t surprising given the subjective aspect of pain. If the patient can tell that the difference is real then it matters to them. 

Does this new device work?

Short answer: no.

Longer answer: not according to the evidence so far presented.

Why do I summarize this evidence as, “no, does not work”? Because the burden of proof is on them to show their device is efficacious. The correct assumption for any novel treatment is that it does not work. 

Why does it seem like it worked in the study?

The control group was poorly designed. Or well designed if your objective was a false positive result. The study is described as double-blinded but the control group got a 2D experience with no therapeutic aspect while wearing a VR headset. They knew they were in the control group. No doubt about it. 

The basic reason for the experimental group, with the 3D therapeutic experience, to report a small improvement is an Expectancy Effect. There are a lot of other factors that go into why treatments that don’t work will lead to positive outcomes in poorly designed study. Enough that it would be it’s own long, multi-part series of posts. (if you want that I’ll need a Patreon first).

Conclusion

I would love a more accessible approach to improving chronic low back pain. But this is not even that since a typical VR set up requires more space than most people’s homes.

It was an interesting experiment. But the real results were negative. Which is important to know. However, the product should not be authorized by the FDA but the FDA is following the laws that they have been given. 

Author: Steven Hirsch, DPT, CSCS

Physical therapist, strength coach, historical fencer.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: