Can an MRI see pain?

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Welcome back to the Forensic Chiropractor podcast.

I have noticed something interesting with  my patients and imaging.  They all want to see a reason for their pain on imaging.  I think what they really want is validation that they hurt for a known reason.  I am not sure most of my patients believe or want to believe that pain can’t be seen on imaging.  Sometime we can see injuries that help explain a patient’s symptoms and sometimes we do not. 

In the forensic or personal injury world we use imaging for a couple reasons.  We always use it to manage patient care.  Imaging can sometimes help determine if a surgical consultation is needed, if we can do conservative care or a variety of different options.  We also use imaging to help form opinions of causation.  I believe that imaging should not be ordered for causation, but for patient management. 

Since causation is not always clear or agreed on, I will used all information to help with causation and the objective evidence is best for causation.  Some of the best objective evidence to help with causation on a person injury case is an MRI.  The study I want to cover today looked into MRI findings in patients with low back pain and patients without low back pain. 

The study is MRI findings of disc degeneration are more prevalent in adults with low back pain than in asymptotic controls: A systematic Review and Meta-analysis by Brinjikji (BRINJICK) et atl and published in the spine journal in 2015.  

This was a met-analysis of case-control studies comparing MRI findings in patients with low back pain and patients without low back pain.  They found 280 studies that covered this subject, but narrowed their review down to 14 studies.  The studies they reviewed only included people age 50 or younger.  The articles they used for the study were published before the Fardon study came out on nomenclature for disc damage.  They admit that this could affect their results since the term bulge, extrusion, protrusion were not based on the same definition. 

Another limitation of their study is that the asymptomatic patients were only asymptomatic at the time of imaging.  They could have had lots of prior low back pain or pain after imaging.  This brings in to question how asymptomatic these patients really were.   Most of these studies did not differentiate between the different types of modic changes.  There was a study that differentiated between type 1 modic changes and Type 2 and 3.  This study has its limitations, but I think it still has some important information.  They stressed that this study is not to be interpreted as a causation study.  This study is not one where we look at MRI findings to help determine new vs. old injuries.  This study helps us understand how likely different findings are to cause low back pain. 

I have talked a lot about causation in most of my podcasts.  I talked a lot about painting a picture of all findings to see if the picture appears to show new vs. old injuries.  You can listen to the older podcasts for a refresher.  As a short refresher course, healthy discs will have no height loss, no decreased fluid in the center, no degenerative osseous changes around the disc and no disc material sticking out beyond the vertebrae.  New disc damage will typically have no loss of disc space height, no degenerative osseous changes surrounding the disc, disc extending beyond the vertebra focally and increased signal in the herniation.  Degenerative or older disc injuries will have a loss of disc space height, degenerative osseous changes surrounding the disc, disc desiccation, circumferential disc bulge beyond the vertebrae.  In general type 1 modic changes are new injuries and type 2 and 3 are from older injuries. 

I have covered all of this information with references to research articles in the past podcasts.  That is important information for causation.  Lets assume we have established causation.  Lets even go as far as to say that both sides agree with causation.  The next step is what does this mean to the patient.  Today’s study helps us understand a little more about what MRI findings will mean to patients.  I have talked about this on other podcasts as well.  One of my favorites was podcast 10 about innervation of discs.  It showed how healthy discs have almost no nerve innervation or ability to feel pain, but damaged discs have nerve innervation everywhere and have the ability to feel pain with normal daily activities. 

Today’s study showed that the following findings are all associated with symptoms: disc bulge, disc extrusion, disc protrusion, degenerative osseous changes and type 1 modic changes.  This makes sense to me and correlates with my clinical experience.  Disc damage alters the function of the disc and joints surrounding the disc and often leads to facet mediated pain.  Disc damage as stated a minute ago also increased nerves in the disc leading to potential for pain with even normal activities.  This shows that really old or new disc problems typically cause symptoms.  Podcast 18 covered basivertebral nerve mediated pain.  The basivertebral nerve goes to the vertebral endplates and is very pain sensitive.  Type 1 modic changes are direct damage to these endplates and have been shown to represent edema and microfractures.  The findings they associated with low back pain are very common causes for my patient’s symptoms. 

They reported that findings not associated with low back pain would be type 2-3 modic changes, central canal stenosis, annular fissures or high intensity zones and spondylolisthesis.  They did report that some of these findings that were not associated with low back pain are the types of injuries that are associated with leg pain.  These studies did not assess leg pain. I know a lot of spondylolisthesis or moving of a vertebra are often associated with older injuries and may not be causes of pain and are often reported as incidental findings.   

They reported that they were surprised by the strong associated of disc bulges causing symptoms since prior studies showed asymptomatic patients with disc bulges.  Podcast 33 and other studies show that the studies showing asymptomatic disc damage is flawed and not accurate.  Today’s study seems to back up the fact that asymptomatic disc damage is not accurate. 

To recap this study showed that MRI findings of disc bulge, disc extrusion, disc protrusion degenerative osseous changes and type 1 modic changes are associated with low back pain.  They do not say that these findings show new injuries that are associated with low back pain, but that patient’s with these findings have low back pain. 

Real world

For today’s real world example I want to talk about an important part of writing a report.  Just showing an injury is not enough and I need to explain what the injury means for a patient and what it will mean down the road.  I will use today’s study and other studies to show that with disc damage patient are more likely to experience pain.  This is a long term pain and is still seen when the disc is a degenerative disc bulge with degenerative osseous changes around the disc.  New disc damage will over time degenerate into disc bulges and will still have the potential to feel pain and as seen in today’s study is strongly associated with pain. 

Insurance companies love seeing degenerative disc bulge on a report and will instantly say this is pre-existing.  This is true that in most cases degenerative changes are new and not related to the injury.  I don’t understand how insurance companies are completely onboard with saying degenerative changes are old and unrelated to the injury and likely the cause for all pain and no pain is related to an injury, but once there is a new injury they have a harder time agreeing that new injuries will eventually be an older degenerative injuries that will continue to cause symptoms.  I think today’s study is a great way to show that with new damage patient’s will likely experience symptoms and need treatment throughout their life.  

It feels like insurance companies often try to place a time frame around how long an injury should last.  I hear strain/sprain injuries should only last around 6 weeks.  I have covered in many podcasts how this is very wrong and that with ligament damage ongoing care is needed to help manage these permanent injuries and their symptoms. This is the same with disc damage there is no time frame around how long it should last, but this study appears to show that damage will cause symptoms ongoing.

My last thought I want to end with today is with patient with only degenerative findings after an injury.  It would appear that the injuries are not new and that they likely would have had symptoms prior to any injury.  Although this is true and supported by today’s study I have covered in prior podcasts that degenerative changes make patient prone to injury with less force.  That means that after an injury a patient is likely to have symptoms ongoing and the potential to have more significant injuries in the future.  I believe patient’s deserve fair compensation for permanent injuries that have been shown to cause ongoing symptoms, need ongoing care and have the potential to make more serious problems if they have future injuries. 

Thanks for listening.  Let me know if you have any questions or topics you would like me to cover.