By their very nature, prescription only medical devices—particularly those that require surgical implantation—are complex products, the design and manufacture of which are not lay person knowledge. So, if you are going to claim such a device malfunctioned, you are going to have to prove it with expert evidence. This is a well-known legal concept. Yet, for some reason the plaintiff (not pro se) in Sundaramurthy v. Abbot Vascular, Inc., 2025 U.S. Dist. LEXIS 64361 (D. Mass. Mar. 31, 2025), after having all his claims except manufacturing defect dismissed on preemption grounds, failed to proffer expert evidence that such a defect existed in the stent graft implanted during his cardiac surgery.
Rather, in the first instance, plaintiff seemed content to rely on a malfunction theory to prove his case. The stent graft balloon could not be retracted therefore it did not “perform as intended” therefore it was defectively manufactured. But the leaps between each step in that equation were far too wide for the court. To prove a manufacturing defect claim, plaintiff has to show that a manufacturing error caused the particular product at issue to be defective and that the defect was caused by the manufacturer and not some intermediary after the product left the manufacturer’s custody and control. Id. at *17-18. The law in the First Circuit, and beyond, is that “expert testimony is required when the nature of the defect . . . and its causal relation to the accident [are] complex.” Id. at *18. The expert evidence rule exists so that when manufacturing processes are sufficiently complex so as to be outside the scope of “general, lay knowledge,” the jury is not left to “conduct guesswork.” Id. at *18-19. That is why Massachusetts courts have not required expert evidence to prove a manufacturing defect in a case involving a sandal but have required expert evidence where the product at issue was a 1964 Pontiac windshield or an epidural catheter. Id. at *19-20. Stent grafts are clearly in the latter category. Indeed, courts have required expert evidence in cases involving Class I and Class II medical devices. Defendants’ stent graft is a Class III medical device, meaning it was subject to greater FDA scrutiny placing it well beyond a consumer product—like a shoe—on the complexity scale.
Plaintiff’s surgeon testified that the stent graft had certain known risks, such as becoming stuck, the balloon not inflating or not deflating, and that it could puncture an artery wall. Id. at *8. The fact that one or more of these risks occurred in plaintiff’s surgery is not evidence that the product deviated from its intended design or was defectively manufactured. Not only would the lay persons on the jury need to understand the manufacturing processes for the stent graft, but also the unique medical circumstances under which the device was employed to be able to determine if plaintiff’s injuries were caused by a defect. Knowledge that no ordinary juror is expected to have.
Apparently seeing the writing on the wall, plaintiff made an eleventh-hour attempt to recast his claim under a res ipsa loquitur theory. He advanced this theory for the first time in response to defendant’s motion for summary judgment. The argument was too late. But more importantly, even if allowed, the court cited multiple cases involving Class III medical devices where res ipsa loquitur was insufficient to survive summary judgment. Id. at *26. A Class III medical device simply cannot speak for itself. It needs an expert to do that. Summary judgment granted for defendant.