Thu v. Willis and the Necessity of Expert Medical Testimony

On March 13, 2023, in a memorandum decision, the Indiana Court of Appeals affirmed a trial court’s decision for the plaintiff in a negligence complaint despite the defendant-appellant’s argument that the plaintiff failed to provide sufficient evidence that the car accident at issue was the proximate cause of his injuries.

In this case, Thu v. Willis,[1] Guy Willis Sr. (“Willis”) and his sons were rear ended by Sein Thu and subsequently filed a complaint for negligence against Thu. The jury found in favor of Willis, and Thu appealed to the Indiana Court of Appeals, alleging that Willis “failed to present sufficient evidence to support the jury’s verdict in his favor.” Particularly, Thu alleged that Willis’s evidence was insufficient because Willis “did not present expert medical testimony to connect the crash to his injuries.”

The court referred to Martin v. Ramos[2] to clarify that expert medical testimony is not necessarily required if a layperson could “readily understand the causation.” In Martin, the Indiana Court of Appeals decided that “when an injury is objective in nature,” the plaintiff may testify to his injury and that testimony may be sufficient for a jury verdict even without expert medical testimony. In his appeal, Thu argued that Willis’s injuries were not objective, but rather too complicated for a lay person to understand. One of Thu’s major points of argument involved the fact that Willis testified to having pain from the accident on his left in addition to a history of sciatica. Thu argued that Willis was not qualified to testify whether his diagnoses were caused by his injuries from the accident or by the prior back pain he already had experienced before the accident.

However, the court agreed with Willis that testimony from a medical expert was not necessary to establish the cause of his injuries. Willis contended that his injuries were objective: the first doctor he visited noted “palpable muscle spasms in his neck”; a nurse practitioner noted “‘pain in his cervical spine and muscle tension’ in his lower back”; and doctors months later noted “‘tenderness’ in his neck and back.” Further, Willis insisted that he had no subsequent injuries after the car accident with Thu, and the new pain he experienced after the accident was different from the pain he experienced previously. The court explained that the preexisting pain did not “automatically necessitate” expert testimony.

Thu raised Daub v. Daub[3] to support his position. The court ultimately found that Mr. Willis’s ability to explicitly distinguish between his preexisting pain and the new pain following the accident distinguished the cases. The plaintiff in Daub suffered significant injuries that required two surgeries and ten days in the hospital, whereas Willis’s pain was only temporary.

Ultimately, because a “lay person could readily understand the connection” between the new pain Mr. Willis experienced and the collision itself, the court held that Willis “did not need to present expert medical testimony to prove the causation of his injuries.”

Because the court issued this holding as a memorandum decision, this case is not binding on any Indiana courts under Indiana Appellate Procedure Rule 65(D). However, the case may still be cited to any court for “persuasive value” under Rule 65(D), and the case may prove to be useful to personal injury plaintiffs across Indiana to establish cause without the need for expert medical testimony.


[1] Thu v. Willis, 22A-CT-1450, 2023 LEXIS 272 (Ind. Ct. App. 2023).

[2] 120 N.E.3d 244 (Ind. Ct. App. 2019).

[3] 629 N.E.2d 873 (Ind. Ct. App. 1994).



The statements contained here are matters of opinion for general information purposes only and should not be considered by anyone as forming an attorney client relationship or advice for any particular legal matter of the reader. All readers should obtain legal advice for any specific legal matters.

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