Gaining Broad Acceptance

June 30th, 2011 - As an adult Chiari patient, like so many others, who was severely affected, initially disregarded if not down-right disrespected by numerous doctors and health care professionals but ultimately decompressed to realize a near full recovery, it is difficult to understand why so many physicians have never heard of Chiari or why so many believe that adult Chiari is simply a benign variant of normal that is rarely the cause of symptoms.

The short answer to this perplexing question lies with a term known as evidenced based medicine. When we say evidenced based medicine we mean that sufficient evidence exists to draw a conclusion based on an acceptable level of uncertainty. I have written about this in the past1. A lot of information that the lay person would find acceptable for drawing a conclusion is simply not acceptable. Reported case studies are not acceptable because they lack statistical power. Retrospective studies are not acceptable because they depend frequently on data collected in the past for another reason and the data that can be difficult to verify. I have discussed in the past that the acid test needed for making firm conclusions are large reproducible well-designed prospective studies. This simply is not the situation unfortunately when it comes to Chiari. Let's look at this situation more closely to understand what the barriers are.

I'll start by contrasting fibromyalgia to Chiari. Look at the chart below. It shows the number of papers published in the medical literature for both fibromyalgia and Chiari versus time. There were very few publications on either of these conditions prior to 1960. What's interesting is that in the nineties the number of publications on fibromyalgia takes off like a rocket. Today the publication rate for fibromyalgia is more than two-fold greater than Chiari.

image002.gif Patients with fibromyalgia and Chiari share many similar symptoms and complaints that can not be objectively measured or verified. If you go back to the nineties, fibromyalgia was basically considered a waste basket syndrome. In other words, when a patient presented to a physician with the symptoms of fibromyalgia the patient was considered to be suffering from depression or some psychological problem and was therefore crumbled up like a piece of unwanted paper and tossed in the waste basket. Tossing such a patient into the waste basket consisted of everything from telling them they were stressed out and needed a vacation to writing them a prescription for an antidepressant.

That is certainly no longer the case today with fibromyalgia. How things have changed! In just a short time, large reproducible well controlled prospective studies have been conducted to yield data allowing conclusions to be drawn with an acceptable level of uncertainty showing that fibromyalgia has its origins in the physical as opposed to the mental realm and that medication can effectively treat this physical deficit. The stimulus for generating these data like it or not lies in the fact that medicine is also about business. There are many more individuals with fibromyalgia compared to Chiari which financially justified investing into fibromyalgia research by the pharmaceutical industry.

Let's return to Chiari or cerebellar ectopia. We say, "but Chiari has been known for a long time" and "there are still hundreds of published papers in respected medical journals". Surely the collective information has value if not offers proof that Chiari is more than an anatomical benign variant of normal. Well, no, unfortunately it does not.

Cerebellar ectopia was first observed by the pathologist John Cleland. He published his findings in 1883. Hans Chiari published a case study later in 1891 and his classical paper describing 21 cases in 1896. So, yes, it has been known for a long time. However, to be able to say that an anatomical difference such as cerebellar ectopia causes significant symptoms is a completely different ball game. Disease is complex. Many malfunctions can occur within the body to cause symptoms. Others possible problems must be systematically and rigorously ruled out before one can say with acceptable confidence that one particular problem or malfunction of difference from the typical situation is cause of the symptoms.

Much of our knowledge of Chiari and the symptoms it causes is historically attributed to the pediatric situation. If you look at the early publications on Chiari you will find that they first centered around pathological descriptions and then advance to the pediatric situation. Chiari malformations in infants and children with symptoms are more obvious or pronounced. Their symptoms and anatomy can be more easily measured objectively. The adult situation is very different and much more unclear. Some adults have no symptoms at all for decades. When symptoms do emerge, how can one be confident that a cerebellar ecotpia or herniation of only a few millimeters that has caused no problems for decades is all of the sudden responsible for the symptoms? One important clue or test would be to show that surgical treatment corrects the patient's symptoms and complaints. Early attempts to demonstrate this however did not exactly produce stellar results. Even today, the failure rate of surgical decompression remains significant.

In preparing this piece, I came across early reports of adult Chiari cases. I wanted to locate the first published paper on a suboccipital craniectomy or hind brain decompression to treat an adult case of Chiari malformation. I don't think I did but I did find two reports from 1969, one was a paper by Smith and Ridley in the British Medical Journal2 and the other was a letter to the editor of the same journal by Douglas N. Golding3.

I found the Smith & Ridley paper of great interest. In it, they report on three adult cases. All three cases were severe. In two cases, decompression resulted in very limited improvement. In the third case, the patient suffered a cardiac arrest during decompression and surgery was terminated. The patient died 24 hours later of a second cardiac arrest. This is what I mean by not so stellar results. I was impressed however with the radiography work up described in the paper in which the Chiari malformation (cut and pasted below4) from the patient described in the first case can clearly be seen.

image004.gif Unfortunately, Golding's report in his letter to the editor of an adult Chiari patient that he decompressed is similarly less than stellar. His case involving a 27 year-old woman concluded as follows. "Unfortunately, the neurological signs have since worsened progressively and she is now severely spastic in all four limbs, though she is still able to work about the house with difficulty and can just about manage stairs."

You might say that these early surgical decompression attempts got things off on the wrong foot in terms of generating a reasonable hypothesis that Chiari malformations in adults may be the cause of symptoms which can be improved by decompression surgery.

There have of course been thousands of decompressions since. There is no standard method used to report outcomes but broadly it seems that about 20% experience a near full recovery, 20% experience no improvement and 60% experience partial improvement of various degrees. This combined with the fact that we still do not have a diagnostic or an objective measure that correlates with symptom severity, retains us in a situation of not having the evidence necessary to conclude with an acceptable level of uncertainty that adult Chiari is more than a benign asymptomatic variant of normal.

We do however have enough information to form a very reasonable hypothesis that adult Chiari causes significant symptoms and decompression surgery can often help.

To move the situation from hypothesis to conclusion which ultimately is needed to get more physicians on board, we need more research in three areas. One, we need to better understand how Chiari malformations occur. Two, we need an objective diagnostic test that correlates well with symptom severity. Three, we need large well designed prospective treatment studies that uses outcome definitions considered valid and widely accepted. Research is going on in all three of these areas but more is needed. The pharmaceutical industry will not invest their dollars into this area for obvious reasons. Government agencies could potentially invest in this research however there is great competition for these funds from other disease areas. The challenge is great but we must stay the course.

In the mean time, given this situation, if you are a patient exploring treatment options it is imperative to go straight to a neurosurgeon with expertise and experience in Chiari. Doing anything less is only likely to be a waste of time. If you have been fortunate to have made the journey with a good outcome and feel passionate about doing something about the situation, I would appreciate hearing from you as there may be opportunities for you to help and get involved.

1The Science Behind the Science

2Brit. med. J., 8 February 1969, 353-355.

3Brit. med. J., 12 April 1969, 119.

4Complete text with images available for free in the Internet.


Ed. Note: The opinions expressed above are solely those of the author. They do not represent the opinions of the editor, publisher, or this publication. Mr. D'Alonzo is not a medical doctor and does not give medical advice. Anyone with a medical problem is strongly encouraged to seek professional medical care.