New Scientist vol 163 issue 2198
07 August 1999 page 18
Is it ethical for surgeons to cut patients open and sew them up without doing anything?ONE of the first things Lynda McKenzie, a 46-year-old Canadian artist and writer with Parkinson's disease, recalls about the operation she had 30 months ago is the dull whirring of a drill as it cut four holes through her anaesthetised forehead. "It's like being at the dentist," she says. "You hear the drill, but you don't feel it."
Later, through the haze of sedation, she heard the surgeon ask for the "implants"—a reference to the fetal cells that are injected deep into the brains of Parkinson's patients in an effort to compensate for neurons destroyed by the disease. After the operation, McKenzie says she felt her Parkinson's had definitely improved.
But McKenzie did not receive any implants. She was part of a control group of patients who had the operation, but not the injection. "I was told that might happen," she says. "But I was sure that I had received the tissue." Her symptoms were temporarily soothed just by the act of healing—the placebo effect.
Placebo surgery—a practice that many doctors thought had been abandoned forty years ago—is making a comeback. It is an integral part of two other clinical trials for Parkinson's treatment currently under way, a recent trial of chronic pain treatment in cancer patients and another for knee surgery. Advocates say placebo surgery allows the same scientific rigour accepted in the rest of medicine to be applied to surgical techniques. But critics question the wisdom—and the ethics—of operating on patients without trying to cure them.
Placebos are best known for their role in drug trials. One set of patients is given the drug, the other set is given an inert substitute. Neither doctors nor patients know who gets what, which stops them prejudging and biasing the results.
By contrast, the principles behind surgery seem obvious. If something is diseased, you cut it out or try to replace it. If something falls off or breaks, you sew it back on or mend it. So surgical techniques are often adopted before they have undergone clinical tests.
But testing surgery with placebos is not a new idea. It was used in the 1950s to test a treatment for angina, in which two arteries in the chest were tied off to direct more blood to the heart. Although three-quarters of patients showed a marked improvement after the procedure, many surgeons were sceptical. Their suspicions were confirmed after a small study by a Seattle doctor, Leonard Cobb, and his colleagues in 1959. Half his patients had the operation, but in the other half, the surgeon cut into the chest but didn't tie off the arteries. To the shock of proponents of the procedure, both groups showed equal improvement (New England Journal of Medicine, vol 260, p 1115). The operation was soon abandoned.
Back to the old ways
Despite this success, the future of placebo surgery didn't seem bright. Surgeons soon returned to their traditional ways. And in the 1970s, ethicists began to worry that patients in clinical trials should be thoroughly informed of any dangers before giving consent. Without much discussion, it was assumed that no patient would agree to fake surgery once they knew of the risks.
The reason for the recent revival of sham surgery in the US is unclear. Some experts suspect it is partly driven by insurance companies which want stricter proof that techniques work before they pay for them.
Curt Freed of the University of Colorado Health Sciences Center in Denver, one of the leaders of McKenzie's trial, says he turned to placebo surgery after reaching an impasse in his research. Along with his colleague, Robert Breeze, Freed had been experimenting with fetal neuron transplants in Parkinson's since 1988.
After years of study, they had developed what appeared to be a successful approach. "All our patients were saying positive things about the therapy," he says. But drug trials with Parkinson's patients had shown that they are highly susceptible to prolonged placebo effects.
Because of this uncertainty, Freed and his team convinced the US National Institutes of Health to fund a placebo-controlled trial of their procedure on 40 patients.
The challenge, says Freed, was to design a study that balanced the safety of the patient against a convincing sham. They decided to drill holes in the placebo patients' heads, but only to touch the protective surface of the brain without penetrating it. Both real and fake operations followed a set script, including—as McKenzie correctly recalled—asking for the implants even if they weren't to be used. Only Freed and the surgeon knew who received the fetal tissue and who did not. The doctors who evaluated the patients over the next year weren't told.
The results of the trial were announced in April at the meeting of the American Academy of Neurology in Toronto, Canada. The researchers found a strong placebo effect—all the patients reported an improvement. However, the study also found that the implants had grown in nearly all patients who received them. And implant patients under 60 years of age showed a 30 per cent improvement in motor skills, compared with those who had the placebo operation—although older patients showed no improvement. The complex results proved to neurosurgeon Michael Walker, former director of the NIH division that funded Freed's work, the crucial role that placebo surgery played. "Without that comparison, we'd be arguing into the next millennium whether the surgery had an effect or not," he says.
But others worry that the research might be sacrificing patients' rights in the hunt for scientific rigour. "Drilling into someone's head is pretty radical," says Bill O'Neill, ethics and science adviser to the British Medical Association in London. "I'd be very surprised for a hospital ethics committee in Britain to approve such a placebo."
William Andereck, chairman of medical ethics at California Pacific Medical Center in San Francisco, says the term placebo surgery is misleading because placebos are innocuous, while surgery always carries a risk. "It's one thing to give patients a sugar pill," he says. "But it's not acceptable to give them strychnine instead."
But if sham surgery has its critics, it also boasts some converts, among them Thomas Freeman of the University of South Florida, Tampa. Initially, a Parkinson's trial led by Freeman was not going to include a placebo surgery control. "I dismissed it on a reflex basis, as most surgeons would," he says. But in the end, he decided it was better to expose a few placebo subjects to some risk than end up promoting a potentially dangerous operation to hundreds of future patients.
But no one is quite sure where to draw the line. Donald Kornfeld sat on the hospital ethics board at Columbia Presbyterian Center in New York city that eventually approved Freed's trial. They decided that the benefits and risks of the placebo and experimental groups were well balanced. And after the trial, placebo patients were given the choice of receiving implants, so treatment was only delayed.
But Kornfeld's committee turned down a similar trial to inject nerve cells from pigs into Parkinson's patients. They decided that the protocol, which called for months of treatment with antibiotics in both groups, was asking too much of control patients. Other centres, however, agreed to participate and the trial is in progress.
McKenzie, who has now had the real surgery, feels she was thoroughly informed. "It's wrong for anyone to say I was a sacrificial lamb," she says. "We're on the last crunch in making advances on this disease. Being in this study is a part I can play."
Philip Cohen
San Francisco
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