The favourable results of treatments can fade over time (the Decline Effect, see later post) for many reasons. Often the initial enthusiasm (bias) of the proponents is not replicated in later studies (see previous blog). But sometimes it can be shown that as the scientific validity of the studies improve, the effect decreases. This is because studies with better scientific methods will (by definition) have less bias (causes of error) and therefore the results will provide a better estimation of the truth. Vertebroplasty (injecting osteoporotic vertebral fractures with cement) is a recent (and controversial) case in point.
Saturday, 26 May 2012
There is a common belief that if something costs more, it must be better; that you get what you pay for. Recently, a friend of a friend (this is not sounding very scientific, but hear me out) went to see two spine surgeons about his neck pain. One surgeon advised against surgery. The other recommended a neck fusion, to be done in the private hospital with an out-of-pocket “gap” (the fee, above and beyond the health fund rebate) of $10,000. He is now considering drawing on his retirement fund to pay for the surgery. Considering that there are surgeons who will perform this operation for no “gap”, is this worth it? Is the price a reflection of quality?
Wednesday, 23 May 2012
There is one thing (out of a list of many) that makes me disappointed with a surgical trainee; it comes after they describe a new case to me and offer their preferred surgical treatment. I then ask them for the evidence supporting their recommendation. They say: “Well, I saw a guy do one once.” This short statement says so much. Firstly, how we are influenced by what we see, particularly when somebody considered to be senior or authoritative does it. It also shows how readily we recommend treatments without good knowledge of the outcomes of that treatment, or of the alternatives. It is easier just to think: “If this guy did it, then it must be OK”.
This is why appendicectomy is so commonly done. Randomised trials have told us that removing the appendix is not necessary on first presentation, and it is associated with a worse long term outcome. Yet if you present to any of my hospitals with suspected appendicitis, you are unlikely to be leaving hospital without having your appendix removed.
Sunday, 20 May 2012
The idea behind "revascularising" coronary arteries is very appealing: “My blood vessels were blocked and the doctors unblocked them”. Like so many things addressed in my blog, this sounds good and seems hard to argue with, unless you look at it scientifically and ask the right questions. ...
Thursday, 17 May 2012
IDET (Intradiscal electrothermal therapy) fits perfectly into the template for a successful placebo treatment described in my earlier blog. It has everything: biological plausibility, high tech equipment, high cost, conflicts of interest, great lab results, encouraging results from early clinical studies, and no advantage over placebo...
Sunday, 13 May 2012
For the boys, prostate cancer screening is another case in point. Screening is easy (just a blood test - a PSA) but like all screening programs it is plagued by overdiagnosis, and the harms from treatment for this condition are also quite significant (high rates of incontinence and erectile dysfunction).
Friday, 11 May 2012
Cancer screening is a no brainer for most people, who think: “why wouldn’t you do it?” It turns out that there are lots of reasons why you wouldn’t do it; reasons that (of course) fall under the all too familiar heading of Overestimating the Benefits and Underestimating the Harms. Time to take a look at the risk-benefit balance.
Monday, 7 May 2012
RF (Radio Frequency, or Radio Frequency Ablation) is used widely. The idea is that a probe is inserted into the affected area which then emits a radio frequency that “changes” (read: damages) the local tissues. It is used in the spine, the shoulder, the wrist and even for liver tumours.
The story with this is so similar to my previous blogs that many of you may be able to fill in the rest of this one for me. In fact, for things like this I should develop a standard blog template to cut and paste in the future. Something like this:
Saturday, 5 May 2012
My last blog on ultrasound and fracture healing brought up the topic of authors with conflicts of interest. This is where the authors have something to gain from publishing favourable results of medical therapies; benefits that might include royalties, stock options, research funding and my favourite: consultancy fees (this is fancy term for a relatively simple process whereby a company gives money to a doctor, often large amounts and at regular intervals). Sometimes the authors are direct employees of the company making the device or drug in question. And sometimes these employees write the article for the esteemed senior author to put his or her name to (ghost writing), thereby giving the article authority.
The acronyms are getting bigger. LIPUS (Low Intensity Pulsed Ultrasound) therapy is commonly used to heal fractures faster, or to get them to heal when they have not. It is a machine that straps on to the limb and is worn for minutes or hours each day, for a few weeks or months. Just like the techniques in my recent posts, it costs several thousand dollars and people assume that if it costs that much and is high-tech, it must be working. Lets cut to the chase.