In Zwiren v. Thompson, 276 Ga. 498 (578 SE2d 862) (2003), the Supreme Court of Georgia set out the law governing the use of expert testimony in medical malpractice cases as follows: Medical malpractice being a civil cause of action, a plaintiff must prove liability (i.e., duty, negligence, proximate cause) by a preponderance of the evidence. "Preponderance of the evidence" is statutorily defined as "that superior weight of evidence upon the issues involved, which, while not enough to free the mind wholly from a reasonable doubt, is yet sufficient to incline a reasonable and impartial mind to one side of the issue rather than to the other." OCGA 24-1-1 (5). The standard requires only that the finder of fact be inclined by the evidence toward one side or the other. Id. at 499. Our Supreme Court then proceeded to apply this well-established law as follows: To establish proximate cause by a preponderance of the evidence in a medical malpractice action, the plaintiff must use expert testimony because the question of whether the alleged professional negligence caused the plaintiff's injury is generally one for specialized expert knowledge beyond the ken of the average layperson. Using the specialized knowledge and training of his field, the expert's role is to present to the jury a realistic assessment of the likelihood that the defendant's alleged negligence caused the plaintiff's injury. In presenting an opinion on causation, the expert is required to express some basis for both the confidence with which his conclusion is formed, and the probability that his conclusion is accurate. Perhaps in the world of medicine nothing is absolutely certain. Nevertheless, it is the intent of our law that if the plaintiff's medical expert cannot form an opinion with sufficient certainty so as to make a medical judgment, there is nothing on the record with which a jury can make a decision with sufficient certainty so as to make a legal judgment. Id. at 500-501. The court went on to say, however, that "reasonable degree of medical certainty," while an acceptable means by which an expert may express the confidence the expert has in the conclusion formed and the probability that it is accurate, is not the required standard. Georgia case law requires only that an expert state an opinion regarding proximate causation in terms stronger than that of medical possibility, i.e., reasonable medical probability or reasonable medical certainty. Id. at 503. In Zwiren v. Thompson, 276 Ga. 498 (578 SE2d 862) (2003), the Supreme Court held: In order to establish proximate cause by a preponderance of the evidence in a medical malpractice action, the plaintiff must use expert testimony because the question of whether the alleged professional negligence caused the plaintiff's injury is generally one for specialized expert knowledge beyond the ken of the average layperson. . . . It is the intent of our law that if the plaintiff's medical expert cannot form an opinion with sufficient certainty so as to make a medical judgment, there is nothing on the record with which a jury can make a decision with sufficient certainty so as to make a legal judgment. Id. at 500-501.