Tag Archives: trigeminal neuralgia

Role of the MRI in TN

On many TN (Trigeminal neuralgia) forums, I came across a number of people having 2nd or 3rd MRI’s in order to obtain proof of a trigeminal compression.  I did the same, had a total of 4 MRI’s and even drove hours to get to the latest model (Tesla 3). They never showed the compression that was found at surgery…

That is why I’m sharing the article below for it resumes what you should know about the role of the MRI in TN.

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Should trigeminal neuralgia patients get neuroimaging?  A neurosurgeon’s perspective

Mark E. Linskey, M.D.
Department of Neurological Surgery
University of California, Irvine Medical Center

Should patients with trigeminal neuralgia get neuroimaging usually in the form of MRI?  Well, my answer to that is always yes but not for the reasons that are often thought.  Many patients are told that what you’re looking for on the MRI is whether or not you have a blood vessel compressing the nerve and then if you find that there isn’t one there you’re not a candidate for microvascular decompression.  Well, nothing can be further from the truth.

The main reason for getting the MRI is to rule out those 2-3% of cases where vascular compression is not the cause where you might have a tumor of the nerve or the brainstem.  You might have a cyst in the cerebella pontine angle.  You might have an aneurysm or an AVM and those require different treatments than treatment for trigeminal neuralgia.  The trigeminal neuralgia there is secondary.  You’re also looking for conditions that are very important for counseling patients for complication risk after surgery.  Examples are patients who have Chiari malformations who have crowded steep angles in their posterior fossa.  They have a much higher risk for hearing loss if they undergo microvascular decompression.  Another example is a large vessel compression something we call a dolichoectatic vertebrobasilar compression.  If you can say that ten times fast.  But while the results of decompression for that are just as good for other blood vessels, the complication risk can be higher.  We’ve published that result and it’s important to know that ahead of time to counsel patients.

The truth is that if a MRI scan shows a blood vessel there, that is a very important factor for predicting a potentially good outcome.  But not showing a blood vessel there doesn’t mean anything.  If you have the classic syndrome you will have the blood vessel there.  The chances of finding it there in my series are at 100%.  In a larger series of Dr. Jannetta’s it’s at 97% and the other 3% if followed over time turned out to be patients in the very early course of their MS and when followed longer were found to have MS later on.

The truth is that 2/3’s of patients have more than one blood vessel compressing and you only see that at surgery.  MRI rarely shows more than one.  So when it doesn’t show any, that doesn’t mean there isn’t a blood vessel there.

In scientific terms, we say that it’s positive predictive value is good, it’s negative predictive value is terrible, and it’s sensitivity is poor.  So, be careful of that.

The other point I’ll make is that one of the tragedies of that misperception that is out there is that often a MRI that shows vascular compression is interpreted by a radiologist not used to interpreting that and then it gets into a MR report as a normal MR of the brain.  A neurologist who may not be comfortable or a family practitioner or an internist who may not be comfortable reading the image themselves may see that and either delay or negate referral for a procedure that could be very helpful.  If you’re going to even interpret the MR, it’s not the radiologist; it’s the neurosurgeon who’s experienced in interpreting this disease who needs to do the interpreting.  And the technique of MR has to be very specific high quality, volume acquisitions, with very fine cuts.

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Other info regarding MRI & TN :

All Pain All Gain !!

I honestly did not expect post-surgery to be that hard… They we’re five of the roughest days I have ever experienced mentally and physically.  Looking back on it, I might not have been the though guy you see in movies but hey, it had to be done and I pulled thru!  No use going into details but rather focus on what remains…

TN Pain slowly going away and a feeling of pride and accomplishment that will definitely last.

I had read it over and over; Surgery is THE best solution with THE best outcome for healty TN patients.

Wanna dance with pain and pills for the rest of you’re life? fine by me but not for me anyways…

Problems

MVD next week !

Having surgery this week made me think about everyone around me that helped me one way or another during this ordeal.  Work colleagues and bosses, we’re so comprehensive with me has I was working (or trying …) and coping with pain.  My sisters have been my biggest fan and never cessed to encourage me from day one.

Soeur

Lastly my wife because as in chess, the queen protects the king. Not once has she issued a single criticism while observing me pass countless hours on the net or hearing my grievances. Instead, she took control of the family boat and revealed herself in her true light, a woman of heart, unconditionally generous, who keeps sprinkling my personal legend …

I don’t know how or when but rest assured I’ll make up for it little Patsy… 

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MVD vs Partial sensory rhizotomy…

My neurosurgeon told me that, during MVD, if they do not find any obvious compression, they usually propose a procedure called “partial sensory rhizotomy” (PSR).  This involves cutting part of the trigeminal nerve at the base of your brain.  It obviously a decision you don’t take on a whim so before going further, I searched more info.  Here’s what I found :

  1. PSR is a commonly used alternative in instances where decompression cannot be performed because no significant vascular compression of the trigeminal nerve is found at surgery.
  2. The more nerve fibers that are cut, the greater the chance of lasting pain relief but also the greater the chance of dense and permanent numbness.
  3. Risks associated with PSR, even with the expert hands of a neurosurgeon, are :
    • Experiencing weakness in the face (on the side of the operation)
    • Difficulties with swallowing, or double vision
    • Risk of pain within the numb area (classified as Trigeminal Deafferentation Pain or called anesthesia dolorosa a long time ago)
    • Most commonly is of partial loss of lower facial sensation (or numbness)
  4. PSR success outcome is lower than a microvascular decompression (MDV). The probable reason behind this may be that MVD is directed towards the resolution of obvious neurovascular conflict whereas in PSR, the primary cause for TN is usually not recognizable.

To me the real question was, would I be willing to accept my present condition of continous pain in a sedentary lifestyle (and the shovel of daily pills) for the rest of my life?

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No matter how many times I weighed the pros and cons, I always came to the same conclusion to go for it…

Let’s hope I end up on the good statistical side …

sdsd

A bit about me (:

Trigeminal neuralgia (TN) challenged me 16 months ago.  I’m presently waiting for a head surgery (MVD) that, i hope, will permit to gain my active lifestyle back.

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Before September 2015, I was enjoying up to 5-6 hours a week of training and/or family activities.  One day without notice, I started experiencing trigeminal neuralgia.

During the last 16 months, I have not counted the titanic amount of time spent trying to gain access to so many different medical professionals, or to surf the net for medical knowledge.  I took charge in the most dynamic way to solve my condition and get back in shape.  I thank myself for being resilient and stuborn.

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At first and since I was physically very active, the symptoms of crisis appeared to me immediately after a physical activity.  I had already endured a herniated disc in the past and it was just as if I had one in my face!  Shortly afterwards, I landed at my dentist, who referred me to an endodontic specialist.  Everything was fine … I had to look elsewhere …

My symptoms:

  • Episodes of severe, shooting or jabbing pain that feet like an electric shock in the mandibular & maxillary branch of the trigeminal nerve
  • Bouts of pain lasting from a few seconds to several minutes
  • Constant aching, burning feeling that’s less intense than the spasm-like pain
  • Pain affecting the left side of the face in areas supplied by the trigeminal nerve, including the cheek, jaw, teeth

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Shortly afterwards, I landed in a neurologist’s office who prescribed me all the right drugs.  At one point, I began to realize that pharmacology would never allow me to eliminate this unbearable and omnipresent pain. I was now conviced the root cause of my pain resided in a vascular element that was compressing my trigeminal nerve. Indeed, I had noticed a direct correlation between the level of my pain and physical activity on my part.  Enough was enough…

A few days before christmas, I arranged to see a top neurosurgeon who proposed to operate on me. Finally !  The procedure is called a microvascular decompression (MVD). It’s apparently the procedure with the best outcome pourcentage. So there I am, inviting you to follow my trail. This rocky path has been my toughest challenge so far, but have no doubt, I will succeed …

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