Disc herniations and radiculopathy.

The last podcast discussed MRIs and findings of new vs old disc damage.  We went over a lot of findings on MRIs of evidence to suggest new vs old injuries.  The last podcast should be helpful with demonstrable objective evidence of injury and causation.  In the medical legal world objective demonstrable evidence is often the key.  What about subjective evidence?  Does the way the patient experiences their injuries have an impact on diagnosis and a medical legal case?  The study I want to go over today shows the importance of having subjective evidence. 

Today’s study is from the journal of radiology clinical neurology published in 2014 by Filippo del Grande MD et al titled “Imaging the intervertebral disk age-related changes, herniations and radicular pain.   They reported that this study was done to examine age-related changes in the disc vs. new injuries.  This study specifically focuses on radiculopathy.  Radiculopathy is damage to the nerve roots as they leave the spine.  Typical radiculopathy will occur in the neck or low back.  This will often lead to arm or leg pain.  Typical radiculopathy will be a disc herniation abutting or compressing a nerve root.  Radiculopathy can be a serious injury.  If the nerve root is completely smashed or compressed then a surgical consultation and likely decompression surgery is likely needed.  The damage done to the nerve can become permanent and will need urgent management.    

The study defined radiculopathy as presence of nerve dysfunction including motor weakness, sensory loss, or diminished deep tendon reflexes, and it is typically accompanied by radiating limb pain which is described as intermittent, lancinating, electric or burning.  Radiculopathy is different than referred pain from other sources like facets or SI joints.  Referred pain is typically deep, dull and achy and rarely refers below the knee or elbow.  With motor vehicle collisions I often seen neck and arm pain or low back and leg pain.  It is really important clinically to distinguish between radicular pain and referred pain.  This is typically done during the examination.  If there is a likelihood of radiculopathy an MRI is likely needed. 

Today’s study showed that before the invention of the MRI it was difficult to diagnose radiculopathy.  Once MRI came out imaging radiculopathy became simple.  This study showed that although we were able to see disc herniations on MRI the diagnosis of radiculopathy was shown to be more complex.  This study showed that the role of radiculopathy requires more than just an MRI showing nerve abutment or compression, and that an inflammatory component was required. 

The study showed that once we have a new disc herniation the natural progression is resorption.  The herniated disc material will be resorbed through macrophage which is a cellular destruction or engulfing of herniated disc material.  This macrophage process is inflammatory and can contribute to radiculopathy.  A new herniation by definition is when the inside of the disc or nucleus pulposis moves outside of the disc.  The nucleus pulposis is immunogenic or the body sees it as foreign material.  An immune process occurs and this creates an inflammatory response.  This inflammation can contribute to radiculopathy.  This study showed that if we take the nucleus pulposis and introduce it into the epidural space without nerve compression we can still cause nerve dysfunction from the inflammatory response, but not pain.  They showed that pain or specifically radicular pain is when we have disc come in contact with the nerve root and inflammation.    They reported quote “Hence radiculopathy and radicular pain are the products not only of nerve compression but also an inflammatory response” end quote. 

This information can help time date new vs. old injuries seen on MRI.  If the patient’s MRI shows disc material contacting the nerve root, but the patient is not experiencing radicular pain then this could be an old disc injury.  If the MRI shows disc material contacting the nerve root and radicular pain then it is one more indicator that this is a new active inflammatory injury. 

This information is very powerful and important for patient care and the medical legal world.  This study shows that for radiculopathy we need demonstrable objective evidence with subjective evidence.  The combination of subjective evidence is supported in the literature as not just nice to have with radiculopathy, but required.   The important part of this article is that subjective complaints are another important part of evidence needed to show new vs pre-existing injuries. 

Showing the importance of subjective complaints this study showed quote “Age-related changes in the disk occur progressively throughout adult life without any relation to symptoms” end quote.  I know in the medical legal world we are looking for demonstrable objective evidence of injury with causation.  This article shows us the importance of subjective evidence.  If we have an MRI with degenerative changes due to age then we would expect that these changes came on progressively throughout their life without relation to symptoms.  IF we have subjective symptoms, especially radicular pain then this study shows that we are likely dealing with a new injury.  We will always need the subjective evidence and this article shows the importance of this.   My favorite part of this article is Quote “ Only a close concordance, a key in lock fit, of an imaging finding and an individual patient’s pain syndrome can suggest causation, which further implies that the imager must know the nature of a radicular pain syndrome if he/she is to suggest a causal lesion” end quote. 

This study addressed the demonstrable objective evidence of new vs pre-existing disc damage as well.  Most of which we covered in the last podcast.  They showed that old disc injuries will show a loss of T2 signal in the disc.  This is due the fact that once a disc is damage it will lose fluid from inside the disc and over time appear to have a decrease in T2 signal.  They showed that old disc damage will alter the mechanics of the spine and lead to osteophytes.  They talked about modic changes and how to show a new vs pre-existing injury.  We went over modic changes last podcast in depth.  As a refresher type 1 modic changes are new active inflammation and are seen with new injuries.  Type 2 modic changes are when the marrow is being replaced with fatty tissue.  Type 2 modic changes are not new injuries and have likely been around for a couple months to a couple years.  Type 3 modic changes are when the bone is replaced by hardened sclerotic bone and is a really old injury. 

Have you ever wondered why steroid injections are done?  Sometimes I wonder if people understand why a patient with a disc herniation or other low back or cervical spine pain would be given a steroid injection.  The truth is that steroid injections will lead to deterioration of the tissues.  This sounds like a horrible way to help with the healing process.  Today’s study showed that conservative therapy is often effective management of disc herniations and given the proper environment they will heal.  The study showed that 71% of disc herniations diminished in size after 2 years and 95% diminished in size after 7 years with just conservative care.  The proper environment for disc herniations is not steroids, but yet we do steroid injections all the time.  The proper environment for a disc herniation to resorb would be normal mechanical function.  The disc will resorb better once the joint surrounding the disc have normal mechanical function.  The area needs movement. 

This study discusses why steroid injections are done for disc herniations.  They reported that steroid injections can help with inflammatory response and allow the patient to be functional and natural history will allow for resorption of the disc material and decrease in radicular symptoms.   The steroid injection should have a large anti-inflammatory response.  This anti-inflammatory response should help with pain and even help with radicular pain.  Bottom line the steroid injections are intended to decrease symptoms and increase activity and allow a time for the disc to resorb. 

Chiropractic care for patients with disc herniations will often involve working with biomechanical joint dysfunction to increase movement and allow the body to resorb the disc material.  After a steroid injection the patient will typically feel better and move better for a few weeks or months and then often the symptoms come back.  The period after a steroid injection can be very helpful for patients to continue chiropractic care and make progress with mechanical dysfunction and help with the natural resorption process. 

Real world example:

A neurosurgeon that I have done a lot of training with back in New York at the New York at Buffalo medical school has repetitively stated that we should never treat a patient’s MRI.  He feels like the MRI is an important tool for diagnosis, but that the patient’s examination and subjective complaints are more important.  I have a young patient that has a large disc herniation in his low back.  The disc herniation is abutting one of his nerve roots, but there is no nerve or spinal cord compression.  The patient saw a provider that took one look at the disc herniation and told him he needed to have surgery.  This recommendation was based off of the MRI and no evaluation.  The recommendation was made off of the MRI and the subjective complaints and physical exam were not factored into the surgical consultation recommendation.  Subjective complaints showed low back pain 7/10 and left leg pain with no numbness, tingling or weakness in the leg.  Physical exam showed no muscle weakness or other neurological deficits.  As seen in today’s study this disc will likely resorb over time with conservative care.  He was given a steroid injection to help manage the pain (not to help manage neurological deficits).  Over the next couple months his pain decreased and he was able to avoid surgery and made a fair recovery. 

Keep in mind that once his disc herniated, he will always have a damage disc.  The disc did resorb over time, but will lose disc height.  This loss of heigh will lead to altered biomechanical function and lead to osteophytes.  The structural integrity of the disc will be compromised make future injuries more likely.  The healing process of a disc herniation will show an increase of growth factor to assist in the healing process.  This healing process has been shown to increase the sensory nerves in the disc.  This makes a structurally weaker disc with a decrease in disc height more prone to feeling pain.  I liken this to a ticking time bomb that you never know when it will go off.  If you have another injury, sneeze, cough or do a   variety of different activities will it cause disc pain.  That is why disc injuries, even with a good recovery are permanent injuries and qualify for impairment ratings.       

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