Discussing news and issues in orthopedics and spine healthcare. This is Spine Talk.
Hi, this is Dr. John Shim, and today I'm here with Jason Mazza,
orthopedic physician assistant. Talking about a very academic
topic, but one that's relevant to doctors and radiologists and people who deal with people with back pain.
We're going to talk about the issue about the high
intensity zone. So,
before Jason talks about high intensity zone. We just need to define it. Basically,
MRI studies will show areas of inflammation to the various body parts.
Radiologists have discovered that there's a small area of inflammation that can be seen at the end
of a disc, and that area of inflammation is considered a high intensity zone.
Well, the question is what does that actually tell us? Jason?
So the study that we looked at comes to us from the Journal of Orthopedic Surgery and Research.
The title of the study is Factors associated with lumbar disc HIZ on t2-weighted magnetic resonance
imaging. A retrospective study of
3,185 discs in 637 patients.
This is a study that comes to us from China.
It's a retrospective study where the researchers were looking at MRI images, chart reviews, and post discography images.
For over 630 patients. The goal of the study was to clarify the correlation between age, gender,
body weight, low back pain, and the presence of an HIZ sign.
The results of the study - they found the highest incidence of HIZ
lesions occurred in the 50 to 59 years old, and those with the highest body weight.
There was a significant difference in the prevalence rates of HIZ lesions, and those that were asymptomatic versus those that were symptomatic.
Overall, in the study the prevalence of HIZ was about 31 and a half percent.
The author's conclusion, was that the presence of an HIZ lesion on a lumbar MRI
was associated with aging, high body weight, and low back symptom.
An HIV, excuse me, an H I Z sign
indicated part of the natural history of disc degeneration, but is not an actual source of back pain.
This goes kind of somewhat against conventional wisdom that all
HIZ lesions cause back pain.
So, Dr. Shim again in kind of simple terms
can you kind of talk more about the HIZ lesion, and kind of what is the relevance of it?
Well, so, you know, I was in my training in the early 90's
I did my fellowship in 1993. At that time, there was lots of excitements about the use of diagnostic studies - MRIs. And
there was a study published by some pretty famous authors where they found these areas of
intensity and inflammation on the back of the discs, and they described these things as high intensity zones. And
at that time the thought was these high intensity zones
identified an acute problem and a source of back pain. So,
We're surgeons, we like to fix things.
So, we now had a finding. So, we decided, let's operate on these high intensity zones and see how people do. Well,
unfortunately, the results weren't very good, and the more we export about high intensity zones - we realized we may not understand it.
Initially, the high intensity zones were considered
acute findings. In other words, if you find a high intensity zone, it means something happened recently.
Well that turned out not to be true because often times if you find these high intensity zones
You'll see that same finding for years.
So, to say that that means something new happened just doesn't make sense. If you have that same finding it's there for years.
It doesn't make sense.
There's been follow-up studies that looked at these high intensity zones, and try to identify the
correlation of the high intensities zones, or something called an angular tear - a tear of the disc.
Well, follow-up studies using CT scans, discograms, and not
didn't always match a high intensity zone with the presence of an annular tear.
So, unfortunately,
this is still a relatively controversial area. To me, its kind of the "we don't know what we don't know" type of scenario
again. The thought that it was a source of pain may be true,
but we know many instances where these high intensity zones have nothing to do with somebody's pain. So, to me, I
don't go by the high intensity zones, simply because I don't know the meaning of that high intensity zone.
The other question I have is - obviously we know that that pain and pain perception across different cultural groups varies.
Now this was a again a Chinese study. So are there other potentially,
biological, maybe
morphological or even genetic differences across different cultures that can change or influence at the outcome of a study like this?
Well, I mean that's a very broad question, and between you and me, I bet there is something that's genetic and cultural.
Because the perception of pain is actually very individual, and it turns out to be also
related to your family history, your family reaction to pain, cultural issues with pain,
acceptability of pain in certain situations.
There are many cultures where people have certain levels of discomfort to their back or their legs or whatnot,
but they know there's nothing that can be done about it. So, they just go forward and carry on. They may have these
feelings of pain, but it doesn't affect them. There's other cultures where a little bit of pain is really significant, and causes significant
disabilities. So, there are cultural issues involved when we're looking at different populations.
To me, you know, I
look at a lot of studies. You do see studies from different areas of the world. They will say in our population of
3,000 Finnish patients, three thousand Chinese patients, two thousand African patients.
They do define their population.
Because we're not a hundred percent sure if what happens in the Finnish population
is then also going to be correlated or found in the Chinese population. So,
to summarize:
The
high-intensity zone is a finding on MRIs, but still at this time,
we do not one hundred percent know what a high-intensity
zone means to patients. It may or may not be associated with pain.
We hope we didn't confuse you more. This is Dr. Shim and Jason Mazza.
Thank you for listening.