In what appears to be the first substantive decision to come out of the multiple suits alleging that a pain pump medical device damages patients, a federal court has granted summary judgment to the defendant. Kilpatrick v. Breg, Inc., No. 4:08-cv-10052 (S.D. Fla. 6/26/09). Judge Michael Moore ruled in favor of medical device manufacturer Breg, finding that the plaintiff, who alleged damage to his shoulder cartilage, did not provide enough reliable expert evidence to link the condition to the defendant’s shoulder pain pump.

Plaintiff Kilpatrick underwent arthroscopic shoulder surgery in 2004 after an orthopedic specialist discovered a tear in his shoulder socket.  To help with post-operative pain, the surgeon inserted a pain pump into plaintiff’s shoulder, which would allow the doctor to administer an anesthetic via a catheter in the patient’s arm. The surgeon injected bupivacaine into the pump’s attached catheter and further filled it with 100 cc’s of anesthetic, which was to be delivered into Kilpatrick’s shoulder over the next 48 hours.  Plaintiff alleges that he began experiencing severe pain in his shoulder in 2006. An orthopedic surgeon diagnosed the pain as glenohumeral chondrolysis, a deterioration of the cartilage, and Kilpatrick underwent shoulder replacement surgery. He then brought suit, alleging negligence, strict products liability, and violations of Florida’s Deceptive and Unfair Trade Practices Act.  Kilpatrick claimed that using the Breg pain pump to administer local anesthetic directly into his shoulder joint caused him to develop post-arthroscopic glenohumeral chondrolysis.

The reliability prong of the Rule 702 analysis was the central issue.  Breg argued, and plaintiff apparently did not contest, that the case should be treated like a toxic tort case for purposes of the Daubert inquiry, in that plaintiff had to offer proof of both general and specific causation. “If anything, determining causation in this case requires an even more complex logical chain than the typical toxic tort case, because the key issue is not merely whether a chemical compound could and did cause injury, but whether that compound as delivered via a particular medical device inserted in a particular location (within Kilpatrick’s shoulder joint) could and did cause injury,” the court found.

The summary judgment motion focused first on general causation, and the ability of plaintiff’s expert to opine adequately under Daubert that the device can cause this type of injury.  The causes of chondrolysis remain disputed, and experts in the medical community have pointed to autoimmune deficiencies, certain kinds of sutures, thermal energy procedures and contrast dyes made from gentian violets as possible risk factors.  Plaintiff’s expert admitted it was a still developing science.

Plaintiff’s expert relied on several published studies to attempt to show causation, which were not directly on point, and the Court found that his extrapolations from the studies were not warranted either.  None of the articles were based on controlled, randomized epidemiological studies of human beings, which are the best evidence. “Significantly, none of the articles explains the mechanism by which bupivacaine damages cartilage, each has important limitations that Poehling does not take into account, and none of them offers an ultimate conclusion as to the general causation of glenohumeral chondrolysis,” the court noted. At most they suggest a possible association.  Association is not causation.  As for the animal studies, the expert did not explain the possible differences in dose-response relationship between humans and rabbits, an important factor to consider in evaluating whether an alleged exposure caused an adverse effect.

As to specific causation, as is typical of many plaintiff experts, Poehling described a process of so-called “differential diagnosis,” trying to rule out other suspected causes such as thermal energy and gentian violet, the contrast dye sometimes used during arthroscopic surgery. This approach cannot, observed the court, make up for a fundamental lack of adequate proof about the general toxicity of the substance.  To “rule in” one cause, even while ruling out other causes, requires a sufficient general causation proof.  At its base, however, the conclusion on specific causation still would be unreliable, the court said, as it was “ultimately rooted in nothing more than temporal relationship.”   That before/after focus is not the basis of good science, the court said, “and Poehling’s dependence upon it further weakens the reliability of his methodology.”  Significantly, the expert had not offered a sufficient explanation of the background risk for genohumeral chondrolysis, casting further doubt on the reliability of the chosen method. He admitted that not only the pain pump — as a kind of drug delivery system — could have caused the injury, but also the anesthetic delivered via the pain pump.  Poehling’s concession that the current state of medical literature is still unsettled about the cause of the plaintiff’s condition seriously undermines the reliability of his methodology, the court concluded.  His methodology had no known rate of error, and thus all he had was a hypothesis that “may be exactly right,” but that currently is “merely plausible, not proven.”

It will be interesting to see what impact the approximately 300 suits pending against pain pump manufacturers in state and federal courts.