When is expert testimony required to prove causation in Utah personal injury cases? Brinkerhoff v. Fleming Explained

The Utah Court of Appeals in Brinkerhoff v. Fleming clarified when expert testimony is necessary to prove causation in personal injury cases, particularly those involving preexisting conditions and multiple accidents.

Background and Facts

Krista Brinkerhoff was injured as a passenger in a November 2016 rear-end collision. However, she had been involved in two prior accidents in 2014 and summer 2016, and did not seek immediate medical treatment after the November incident. Four months later, she began chiropractic treatment. Her expert witness, Dr. Clayton, opined that her injuries were permanent and caused by the November 2016 accident. During deposition, it was revealed that Clayton relied on undisclosed medical articles and an intake sheet, and when presented with Brinkerhoff’s complete medical history showing preexisting conditions, he revised his causation opinion.

Key Legal Issues

The case presented two critical issues: (1) whether the expert’s testimony should be excluded under rule 26(a)(4)(A)(iii) for failing to disclose materials relied upon, and (2) whether expert testimony was required to prove causation given the complex medical history.

Court’s Analysis and Holding

The court affirmed exclusion of the expert under rule 26, finding that undisclosed materials were “substantive in nature” and prejudiced opposing counsel’s deposition strategy. On causation, the court distinguished Sheppard v. Geneva Rock, noting that while expert testimony isn’t always required when causal connections are “readily apparent using only common knowledge,” Brinkerhoff’s case involved preexisting injuries, delayed treatment, and multiple accidents that made causation too complex for lay jurors.

Practice Implications

This decision reinforces strict compliance with discovery disclosure requirements and clarifies that the Sheppard exception for lay causation testimony applies only in straightforward cases. Practitioners must ensure complete disclosure of all materials experts rely upon and should anticipate needing expert testimony in cases involving preexisting conditions or complex medical causation issues.