Regardless of what factual theory of negligence a lifting injury plaintiff pursues, the plaintiff must prove that the negligence of the defendant caused the injury at issue. As simple as this concept appears, the nature of the plaintiff’s causation burden in a lifting injury is often poorly understood and is, in fact, very hard to meet. To prove causation, the plaintiff must show both that the defendant’s negligence was a substantial factor or the “but for” cause of his injuries and also that his injury was “foreseeable.” This part of the series addresses “but for” causation. The next addresses “foreseeability.”

Analysis of causation in lifting injury cases begins with the Texas Supreme Court’s opinion in Leitch v. Hornsby. Leitch involved a lifting injury in which the plaintiff claimed that he should have been provided with a back belt. The Court assumed without deciding that the plaintiff’s employer owed a duty to supply him with a back belt. (This assumption is questionable as addressed in Part III of this series.) The Court also assumed without deciding that lifting the object at issue caused the plaintiff’s back injury. The Court then addressed the evidence relating to causation:

The record shows [plaintiff’s] treating physician testified that lifting the cable reel caused [his] back injury.  However, in response to a question about whether [plaintiff’s] injury could have been prevented by the use of a lift belt, [plaintiff’s] treating physician testified:  “I would be unable to comment.  I don’t think there is anything that would be available to say yes or no in that respect.  This testimony is no evidence of causation.

[Plaintiff’s] co-worker . . . expressed his opinion that the use of a lift belt would have eliminated [plaintiff’s] injury.  [Defendant] argues that [the co-worker’s] testimony is no evidence, because as [defendant] objected at trial, [the co-worker] was not qualified to testify about whether lifting equipment would have prevented [plaintiff’s] injury.  We agree.  [The co-worker’s] testimony has no probative worth and is not proper evidence of causation because his testimony amounts to mere conjecture, and because he was not qualified to testify about what type of lifting devices might have prevented [plaintiff’s] injuries.  [citations omitted].  Therefore, this is no evidence to support the jury’s verdict.

Thus, Leitch holds two things of great significance to a lifting injury case:  (1) the plaintiff has the burden of showing that the negligence of the defendant, and not merely the incident at issue, caused his injury; and (2) expert testimony, probably medical testimony, is required to meet this burden.

The logic of Leitch applies to all lifting injury cases and not just back belt cases. Accordingly, courts have applied the same rule to inadequate assistance claims generally and the failure to adduce competent expert testimony on this issue has led to the authors obtaining a summary judgment in several such cases including as examples: Sanders v. Home Depot and Lewis v. Randall’s Food & Drug. The reasoning applies with equal force to NIOSH RLE claims or any other lifting injury negligence theory. Put simply, the plaintiff must prove through competent expert testimony that he would not have been injured but for the defendant’s negligence. If the plaintiff’s claim is that he did not receive adequate assistance, for example, he must show that assistance would have prevented him from being injured. By reasonable inference, if the negligence theory is that the plaintiff was required to lift too much weight according to some interpretation of the NIOSH RLE, then the plaintiff must show he would not have been hurt if he had lifted some other amount consistent with the RLE. In theory, in a particular case, the plaintiff might have to show that lifting forty pounds would not have injured him but lifting fifty-five pounds did. And the plaintiff must meet this burden with reliable, admissible expert testimony under Leitch. Since such testimony addresses injury causation, it is very likely that a medical or similarly qualified expert must fill this particular evidentiary gap. In the author’s experience, most plaintiffs do not even try to obtain the needed testimony.