Many years ago, as I read through the July 1998 edition of Discover magazine, I came across a fascinating essay entitled “First, Do No Harm”, by Frank T. Vertosick, Jr. (I later learned he was the author of a number of excellent books, including
When Air Hits Your Brain and Why We Hurt: The Natural History of Pain.) When I started reading it, I was idly curious; when I finished it , I was determined to skeptically examine the way medical decisions were made.
Sadly, I can’t provide a link to the article – although much of the content of Discover is available in various indexing and archival services, that particular commentary isn’t for reasons of copyright. But if you have access to back issues of the magazine, I highly you recommend you take a look at that particular edition; the essay begins on page 106.
What was so powerful about the essay that I remember it vividly more than a decade after I read it? Let me show you the bolded quote prominently displayed on its first page:
In the 1970s neurosurgeons began performing an operation designed to save lives. It actually risked them. But no one bothered to determine that for 20 years.
The human scalp is extremely well-supplied with blood to help keep body temperature under control by radiating away excess heat. In terms of immediate physiological requirements, the scalp doesn’t need anywhere near the total amount of blood that flows through it. Additionally, the peripheral arteries of the face and scalp tend not to become restricted or clogged with fatty deposits, with the result that many older patients have excellent blood flow in all parts of their heads but their brains.
Doctors began to think that redirecting this excess blood supply might be a good way to mitigate the devastating effects of strokes. When the brain wasn’t getting the blood it needed, why not borrow from the scalp? So in 1967, Dr. Gazi Yasargil of Switzerland was the first to conduct an extracranial-intracranial (EC-IC) bypass in humans, threading scalp arteries through the skull and grafting them onto the surface of the brain. Between then and 1976, he offered the surgery to 84 patients with a history of stroke or transient ischemic attacks, temporary blockages of blood in the brain that often warn of later strokes. In that time, only three of the patients had further strokes; based on older studies of similar patients, Yasargil concluded that more than half of his patients would have had strokes if he had not performed the surgeries, and that the EC-IC bypass was a highly effective preventative treatment.
Other neurosurgeons hadn’t waited for even this preliminary study to be concluded before offering the bypass themselves, years before any long-term investigation was possible. Thousands of surgeries were performed before even Yasargil’s results were published. As Vertosick reports:
Microsurgical laboratories sprang up overnight to teach the fine skills required for joining spaghetti-size arteries with sutures invisible to the naked eye. Large hospitals and universities aggressively recruited experienced bypass surgeons. Technically elegant and very lucrative, the operation became the darling of the neurosurgical community.
But technically early studies like Yasargil’s were only suggestive, not definitive. There was no proof that the therapy worked as well as we thought it did – they compared patients treated with surgery in the present with untreated patients from the past. That introduces the potential for biasing the results. Direct evidence would require comparing treated and untreated patients from equivalent populations in the present, with the absence of treating serving as a control.
In 1977, the National Institute of Neurological and Communicative Disorders and Stroke (NINCDS) began a study designed to do exactly that. 71 participating neurosurgical centers randomly assigned high-risk patients to either EC-IC followed by aspirin or aspirin alone. Nearly 1,400 patients had been studied when the trial ended in 1985.
Dr. Vertosick attended the conference at which the results of the study were publically released. Instead of confirming what the physicians believed to be true, the results abolished it. The surgery didn’t reduce the risk of stroke no matter how the data was examined. In fact, when deaths and strokes resulting from the surgery were included, the surgically-treated groups had more strokes with greater mortality than the groups given aspirin alone, averaging 14% more.
In other words, the EC-IC bypass wasn’t just useless, it caused significantly more strokes and deaths than doing nothing.
Yasargil’s beautiful theory died that day, slain by ugly facts. The now-wasted hours I had spent bypassing rat arteries flashed before my eyes. At the conclusion of the Honolulu talk, one of my colleagues approached me, cupped a hand to his ear, and lamented, “Did you hear that noise? The doors to a hundred microsurgical laboratories just slammed shut. For good.” Bypass mavens fought hard to save their operation, but to no avail. After a brief and acrimonious debate over the validity of the NINCDS study, the bypass era finally ended. Insurance companies stopped paying for the operation, halting its use; many surgeons still believed in it, but not enough to do it for free.
Although a minuscule number of bypasses are still performed for two rare, life-threatening brain diseases, the operation no longer has any role in the wholesale prevention of stroke. It now lies buried in the cemetery of dead therapies alongside bloodletting, head irradiation for ringworm, and a host of other harmful “cures”. Yet for nearly two decades, the best brain surgeons on earth inflicted thousands of operations on unsuspecting patients in the mistaken belief that the procedure was helping them. In doing so, they caused more death and destruction than the disease itself.
How could they have been so wrong?
That’s what the next post will be about.