United States District Court Judge William H. Yohn, Jr. recently had the opportunity to consider whether expert testimony in a medical malpractice action should be precluded on the basis of Federal Rule of Civil Procedure 702 and Daubert v. Merrell Dow Pharmaceuticals. The case, Ellison v. United States, 753 F. Supp. 2d 468 (E.D. Pa. 2010), alleging negligence by dentists at the Philadelphia Veterans’ Medical Center, was before Judge Yohn on the basis of the Federal Tort Claims Act. Accordingly, the United States substituted itself for the named defendants and has assumed defense of the case.

The plaintiff, Christopher Ellison, experienced a debilitating stroke shortly after undergoing a tooth extraction. During the extraction, Mr. Ellison’s blood pressure dropped several times. Each time, the procedure was paused, but continued after Mr. Ellison’s blood pressure returned to an acceptable level. In support of his claims, Mr. Ellison produced expert reports by Stuart Super, DMD on the standard of care, and Scott Kasner, MD on causation.

Dr. Super opined that the dentist who performed the extraction violated the standard of care by continuing the extraction in the face of multiple episodes of hypotension without obtaining a medical consult and by failing to place Mr. Ellison under medical supervision following the procedure. The United States sought to preclude the testimony of Dr. Super on the basis that it was not reliable and not relevant on the basis of Daubert and its progeny.

First, the United States argued that Dr. Super could not establish that his opinions reflected the standard of care generally accepted by oral surgeons as opposed to his own personal beliefs. Judge Yohn held that the deposition testimony cited by the defendant in support of this argument was not dispositive. Taken as a whole, Dr. Super demonstrated that he was familiar with the standard of care based on his many years of practice in the field.

Second, the United States argued that Dr. Super could cite to no medical literature which supported his opinions. Instead, the defendant argued, Dr. Super’s opinions were contradicted by a leading dental text. Again, Judge Yohn cited to Dr. Super’s extensive experience managing similar patients, teaching students, and examining candidates for the American Board of Oral and Maxillofacial Surgery. The Court noted that Dr. Super did rely on medical literature and otherwise explained his disagreement with the literature relied on by the defendant. Judge Yohn stated, “the question is not whether Dr. Super’s opinions are correct but whether those opinions are based on ‘good grounds.’” He found that they were. He also found that Dr. Super’s opinions were relevant to the plaintiff’s claims.

The defendant also sought to preclude the opinion of Dr. Kasner that the hypotension experienced by Mr. Ellison during the extraction contributed to the development and extent of his stroke. The United States argued that Dr. Kasner’s opinion regarding the subtype of stroke suffered by Mr. Ellison was unreliable because Dr. Kasner, who was Mr. Ellison’s treating neurologist, did not perform a commonly used diagnostic technique for classifying stroke subtype. Dr. Kasner testified that he reached his conclusion by performing a differential diagnosis. The Third Circuit, Judge Yohn wrote, has repeatedly held that a differential diagnosis is a reliable methodology; a doctor is not required to rule out all alternative causes of a patient’s illness. Finally, the United States argued that Dr. Kasner’s testimony should be excluded because he could not rule out that first unavoidable episode of hypotension was the cause of Mr. Ellison’s stroke. Judge Yohn accepted the plaintiff’s argument that he could satisfy his burden in this regard by merely showing that the defendant’s negligence increased his risk of harm. Therefore, Dr. Kasner did not need to identify which episode of hypotension caused the stroke.

Accordingly, Judge Yohn denied the defendant’s motion to preclude the plaintiff’s experts and the accompanying motion for summary judgment which was based on the preclusion of one of both of Plaintiff’s experts. In allowing the case to proceed to trial, Judge Yohn stated that “The issues raised by defendants are, of course, relevant for cross-examination at trial and consideration by the fact-finder in evaluating the testimony of the various expert witnesses.”