In order for evidence of a prior injury or preexisting condition to be admissable in a Nevada trial, a defendant must present by competent evidence a causal connection between the prior injury and the injury at issue. FGA, Inc. v. Giglio, 128 Nev. ____, ____, 278 P. 3d 490, 498 (2102). Furthermore, untless the connection is readily apparent to a layperson, an expert witness must be used to establish it.
