This argument can be used in the case of just about any off-label pioneering. I recall a recent medical case in which physicians experimentally injected Botox into the larynx of a young girl with Tourette syndrome. Their theory was that it would calm her vocal cords and lessen her ticks. The treatment didn’t work. Also, there was no scientific evidence to back up this usage (other than the theory post by the physician). On top of that, the treatment had real potential to harm the patient (and much more than that presented by a diagnostic tool measuring electrical resistance at that).

Although I do see your argument, and if a doctor actually made it past the first one or two cases and was able to justify some clinical effectiveness, then I can see where a judge might rule in favor of the physician. However, the true barrier to innovation lies in the impedance inherent in taking the risky step of pioneering a new method of treatment on that first patient. In such a case, where neither FDA approval nor anecdotal evidence of efficacy would be present, a physician would be hard pressed to provide evidence that his treatment was both effective and did not present a potential for harming the patient.

However, this all still presumes that the physician (or his attorney) could argue past the other clauses stating “that medical review boards are able to rely on their own expertise in evaluating medical practices” and that no other evidence was necessary to convince “a layperson that he was using a machine for purposes for which it was not designed and for which he was not specifically trained.” The evidence consisted of a lack of FDA approval and one contradictory expert opinion.

Furthermore, the ruling states that “Generally, Washington law does not require that expert testimony be provided to MQAC” and that the MQAC can “draw inferences from the evidence presented to them.” Furthermore, “it is not inappropriate for MQAC to draw its own conclusions as to the acceptable standard of care.” So, the expert testimony regarding efficacy would not have been necessary for MQAC to make their decision anyway.

I would hope that this case isn’t used as precedent for claims of malpractice. However, the wording of the affirmation still appears to loosen the reigns on what type of behavior actually constitutes malpractice. In my opinion, the Supreme Court would have been better off leaving out “the lack of FDA approval” as proof of ineffectiveness. In the case of Dr. Ames, it would have been simple enough (and less consequential) to affirm the ruling on the basis of supplemental expert testimony affirming the lack of clinical efficacy of LISTEN in treating allergies.

I think you overlook a vital clause of the court ruling and in so doing exaggerate the extent to which malpractice lawsuits will increase. The justices did not write that the usage of the device in question represented malpractice “simply” because it was not FDA approved, but additionally that Dr. Ames:

“Led patients to believe LISTEN could treat and diagnose allergies, when in fact it could do neither, placing these patients at risk of harm.”

This statement is crucial, because it implies that if LISTEN would have held some type of legitimacy or effectiveness towards treating allergies–whether FDA approved or not–then the burden of harm may not have been reached. The efficacy of many off-label drugs, treatments and devices while not possessing the FDA stamp of approval, has been noted in reputable medical journals, demonstrated through lab studies, or largely accepted within a specific field of medicine–i.e. amongst a majority of doctors and practitioners.

If an off-label treatment held wide spread support amongst a large portion of the medical community–for instance the use of aspirin you noted before it was sanctioned–then any harm the treatment may happen to cause would have to be weighed against its observed benefits. As a matter of public policy, this is true even if the drug in question was not designed for that specific purpose.

In future cases which argue malpractice turns merely on the presence of FDA approval, the judges will surely also look to the evidence concerning the drugs’ merits.