Law & Medicine

The evolving role of expert testimony


Question: Which of the following statements regarding the law on evidence is incorrect?

A. Expert testimony is always needed to establish the applicable standard of care in a negligence lawsuit.

B. According to the Federal Rules of Evidence, a witness may be qualified as an expert based on knowledge, skill, experience, training, or education.

C. It is the judge, not the jury, who determines whether a witness is admissible as an expert.

D. Expert testimony is a requirement in medical malpractice lawsuits, unless a plaintiff can successfully invoke the res ipsa loquitur doctrine.

E. Only a few states have enacted statutes specifying that an expert must be in the same specialty as the defendant, and in some cases, a nonphysician such as a nurse or pharmacist may be allowed to testify.

Answer: A. Under the tort of negligence, a defendant’s conduct is measured by what is expected of the reasonable person – the man on the street. The jury can usually decide on its own, without the aid of an expert, what that level of care ought to be. However, in medical malpractice lawsuits, the law requires an expert to testify to the requisite standard of care, as this determination is believed to be beyond the scope of the layperson.

An exception, rarely invoked, is the res ipsa loquitur doctrine, where “the thing speaks for itself.” There, an expert is not necessary because of common knowledge, e.g., when a surgeon inadvertently leaves a sponge or instrument inside a body cavity.

Whether one is admitted as an expert is within the sole discretion of the judge, who is guided by the Federal Rules of Evidence. Typically, an expert is in the same medical specialty, but there are instances of professionals of unlike specialties qualifying as experts. Examples include a nephrologist testifying against a urologist, an infectious disease specialist offering an expert opinion in a stroke case, a pharmacist testifying on the issue of a medication side effect, and a nurse on bedsores.

We had previously reviewed the law governing expert medical testimony in these columns.1 However, three recent cases awaiting final adjudication caught our attention, as they raise important and serious legal issues.

The first frontally suggests that jury members may rely on their own notion of what constitutes an appropriate standard of care. Although it is established law in Maryland that expert testimony is required to set that standard in medical malpractice litigation, the recent Maryland case of Armacost v. Davis appeared to modify this principle, leading to a plaintiff verdict.2

The facts involved a neurosurgeon’s anterior cervical discectomy and fusion surgery, which was complicated by a pinpoint opening at the end of the incision. This eventually developed into a MRSA abscess. In his lawsuit, the plaintiff alleged that surgery was neither medically necessary nor appropriate, that there was no proper informed consent, and that the diagnosis of his postoperative infection was delayed.

A pivotal part of the trial centered on a Baltimore county judge’s instructions to the jury that it could consider what a layperson would deem reasonable standard of care. Moreover, the judge refused to modify the jury instructions when the doctor-defendant objected and asked that the standard of care be measured by the expectations for a neurosurgeon. The jury returned a verdict in favor of the plaintiff in the amount of $329,000.

Upon appeal, the Court of Special Appeals of Maryland ruled that the jury instructions were improper and therefore ordered a new trial. It held: “Medical malpractice claims are not general negligence claims, and so jury instructions on general negligence, although correct statements of Maryland law, are not supported by the facts of a case centered on the allegedly negligent conduct of a physician. Accordingly, we hold that the trial court erred in giving general negligence instructions in a medical malpractice case.”

The case is now before Maryland’s highest court, the Court of Appeals of Maryland, which is expected to uphold this decision and reject the reasonable person (instead of reasonable doctor) standard used by the lower court.

The second case deals with whether a jury in a medical liability trial may be prejudiced if they hear four medical experts testify for the physician and just one expert testify for the plaintiff. In Shallow v. Follwell, the defendant doctor performed a laparoscopic hernia repair, which was complicated by bowel perforation, atrial fibrillation, sepsis, and death.3

At trial, plaintiffs produced one expert witness, whereas Dr. Follwell had four, with expertise in cardiology, critical care, vascular surgery, and colorectal surgery. The trial court judge instructed the jury not to give weight to the number of experts on either side, and based on the testimony, the jury found that Dr. Follwell did not cause the perforated bowel or the patient’s death.

However, on appeal, the Missouri Court of Appeals overturned the verdict after finding that the trial court erred in allowing “unfairly cumulative and prejudicial repetition of certain expert opinions.” The Missouri Supreme Court is currently being asked to render a final opinion on the matter. In its supporting brief, the American Medical Association’s Litigation Center is urging the high court to “ensure that Missouri trial judges are empowered to safeguard the use of sound science in their courtrooms,” and that “given the highly specialized nature of medicine today, multiple experts may be required to ensure a jury has a proper understanding of the relevant medical science.”4

The third case addresses whether trial judges can suppress expert witness testimony attesting that a known complication of a medical procedure can occur absent any negligence.

The case involved a laparoscopic hysterectomy performed by a gynecologist. The patient’s bowel was perforated during the procedure.5 Expert witnesses from both sides testified about bowel perforation and professional standards, and the trial court allowed the defendant’s expert to state that such an injury was a commonplace risk even if surgery was performed properly.

The plaintiff objected to this testimony; but the trial judge overruled the plaintiff’s objection, and the jury found in favor of the gynecologist. Upon appeal, the Pennsylvania Superior Court reversed, concluding that the defendant’s expert testimony was irrelevant and misleading, and immaterial to the issue of whether the defendant’s treatment met the standard of care. It held that the evidence was inadmissible and ordered a new trial. The case is now before the Pennsylvania Supreme Court.

Dr. S.Y. Tan, emeritus professor of medicine and former adjunct professor of law at the University of Hawaii, Honolulu

Dr. S.Y. Tan

The foregoing three cases are yet to be finally adjudicated, but controversies in these and similar issues can be expected to continue. Expert testimony is dispositive at trial, and both sides rely heavily on it. Little wonder malpractice litigation is frequently framed as a “battle of the experts.”


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