BARRY v. DEPUY SYNTHES COMPANIES
Authored by: Jeremy J. Gustrowsky
A recent Federal Circuit decision has significant implications for how courts handle expert testimony in patent cases, especially when it comes to claim construction and survey evidence. The case revolved around Dr. Mark A. Barry’s allegations that DePuy Synthes Companies and related entities induced surgeons to infringe his patents—U.S. Patent Nos. 7,670,358, 8,361,121, and 9,668,787—covering surgical tools and techniques for correcting spinal deformities like scoliosis.
At trial, the district court excluded the testimony of Dr. Barry’s two key experts: Dr. Walid Yassir, who opined on infringement, and Dr. David Neal, who conducted a survey to estimate how often surgeons used the accused tools in an infringing manner. The court reasoned that Dr. Yassir’s opinions contradicted its construction of the term “handle means,” and that Dr. Neal’s survey suffered from methodological flaws. With both experts excluded, the court granted judgment as a matter of law in favor of DePuy, effectively ending Dr. Barry’s case.
On appeal, the Federal Circuit found that the district court had abused its discretion. The appellate judges determined that Dr. Yassir’s testimony did not actually contradict the court’s claim construction but rather applied it in a way that a reasonable jury could accept or reject. The court emphasized that disputes over how an expert applies a claim construction are factual matters for the jury, not grounds for exclusion. Similarly, the court held that Dr. Neal’s survey, while potentially imperfect, was not so flawed as to be inadmissible; its limitations went to the weight of the evidence, not its admissibility.
The Federal Circuit’s decision underscores the importance of allowing expert testimony to be tested through cross-examination and jury evaluation, rather than being excluded outright unless it clearly contradicts the court’s legal rulings or is fundamentally unreliable. The court reversed the district court’s exclusion of both experts and the grant of judgment as a matter of law, remanding the case for a new trial where both Dr. Yassir and Dr. Neal may testify.