Archive For The “Epistemology” Category

Adjacent Segment Disease: Incidence

By | May 3, 2015

The real mystery is why some people get it and some people don’t. If increased wear and tear on the next segment above or below were an inexorable concomitant of all fusions we would expect to see it to some degree in all cases of fusion, worse in some and less severe in other patients. […]

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The Predictive Value of MRIs in the Diagnosis of Axial Back Pain

By | March 5, 2015

Let us assume that 100 people complaining of pure axial low back pain come into the waiting room at Schlesinger Pain Centers in Burbank. For simplicity we will also assume that there are no malingerers or people with rare causes of back pain in the group. Using the prevalence data from the last blog we […]

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The Diagnosis of Axial Back Pain

By | March 4, 2015

The most common clinical problem that we face at Schlesinger Pain Centers is low back pain and it comes in two distinct varieties, axial and radicular. Radicular back pain is defined as pain that radiates into the buttock or the leg usually in the distribution of one or more spinal nerve roots. In rare cases […]

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Predictive Value: Sickle Cell Anemia in China

By | March 3, 2015

Let us now assume that some overeager field worker from the World Health Organization has gotten a grant to take our easy, cheap, 99% sensitive and 99% specific test for Sickle Cell Anemia and start a screening program in Beijing. The test remains the same but the prevalence of Sickle Cell Trait, not Disease is […]

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Predictive Value: Sickle Cell Anemia in Nigeria

By | March 2, 2015

Now let’s take a look at the example that I have been promising you. Suppose we had a cheap test for Sickle Cell Anemia that is both 99% sensitive and 99% specific. That sounds like a pretty good test, doesn’t it?   Let’s say that we go to Nigeria and test 100,000 people for the disease. […]

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Predictive Value

By | March 1, 2015

No test regardless of the sensitivity and specificity should ever be used without taking a good history and performing a careful physical exam. At Schlesinger Pain Centers we know that the reason for this is that the incidence[1] of any disease varies with the patient population and the predictive value of the test is greatly […]

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By | February 28, 2015

The converse of sensitivity, which is a measure of the frequency of false negatives is specificity, which is a measure of the frequency of false positives or Type I errors. The mathematical definition is the percentage of people without the disease in question who in fact have a negative test. A real world example can […]

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By | February 27, 2015

As we have said above the majority of the complexity in medical decision-making results from the uncertainty of our information. The first type of uncertainty that we will deal with is the problem of false negatives or Type II errors, which is the possibility that someone with a negative test for a disease may actually […]

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The Mystery of Medical Management: Why Is Everything My Doctor Says So Complicated

By | February 26, 2015

Medical management is complicated at the outset by two mutually incompatible mandates imposed by our society. Most patients approach their physician in a spirit of subordination, seeing him as an expert able to weigh competing pieces of information and make a decision that they themselves are incapable of, much as a child might approach a […]

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Defining Normal

By | February 17, 2014

In this blog I would like to explore the important distinction between average and normal. In the blog entitled “Health and Disease” I spoke about the importance of how one defines normal. A common practice in medicine is to look at the results of a particular test and select the mean or the median value […]

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