In the USA, the number of operations conducted each year rose from 14 million in the early 1970s to 23 million in 1989.
Extracranial/intracranial bypass to reduce the risk of stroke, was first introduced in 1967 and widely adopted by the mid-1970s. In 1987, findings of a random trial of 1,377 patients found no discernible difference in the incidence of strokes between patients who had received operations and those given aspirin. Carotoid endarterectomy, the surgical removal of the diseased inner layer of the artery in patients with varying degrees of stenosis (narrowing of the arteries), is also a procedure designed to prevent strokes. A European study found that in severe forms of stenosis, each ten operations might prevent two strokes and cause one.
The development in 1988 of laparoscopes, surgical devices which can be used to conduct operations without cutting open the body, has started a fashion in laparoscopy. Because the surgery is "blind" (aided by small internal cameras), in the hands of the inexperienced, vital arteries or organs can be damaged. Without thorough checking, bits of gallstone can be left behind and block the bile duct. Another concern is that removal of the gall bladder (cholecystectomy) is now so simple that the mere finding of gallstones may prompt a surgeon to take out the gall bladder, even though gallstones do not always cause problems.
Surgery has never been subjected to the same rigorous evaluation as pharmaceuticals. A new operation does not have to be tested first on animals. Unless it has been explicitly identified by a surgeon as experimental, it can be performed without peer review; there does not need to be any formal experimental design; and there is no need for follow-up studies to review the new technique. In many instances, surgeons are free to try out new techniques whether qualified to do so or not.
Surgical skills vary greatly. A surgeon who, as a result of his personal experience, believes an operation works will – even in the face of conflicting data – regard it as unethical to deprive his patients of its benefits. Thus random clinical trials can be performed only when there is uncertainty. The personal qualities of the surgeon cannot be discounted in clinical trials. Patients tend to do better under an enthusiastic surgeon. Nobody would advocate that surgical clinical studies should include dummy operations or unrelated surgeons and patients.