Pina

*20 *534 INTRODUCTION

Appellant Vincent Pina brought this personal injury suit against respondents County of Los Angeles and Los Angeles County Sheriff's Department (collectively the County), alleging, inter alia, that the County negligently caused a bus on which he was a passenger to strike a pillar in 2013. Appellant denied injury immediately after the accident but reported pain soon thereafter, obtaining treatment and diagnoses of spinal injury from Gary Chen, M.D., and chiropractor Philemon Tam, D.C. At trial, appellant admitted sustaining injury in a separate bus accident in 2016, for which he sued the Los Angeles County Metropolitan Transportation Authority (MTA). The County also introduced evidence that appellant was struck by a car in 2010. Nevertheless, Dr. Chen opined that the 2013 accident caused the injuries for which appellant claimed damages, including injuries requiring future surgery. Pursuant to Code of Civil Procedure section 2034.310, subdivision (b), the trial court allowed the County to call Robert Wilson, M.D. -- whom the MTA had retained to examine appellant in his separate lawsuit, but whom the County failed to designate as an expert in this case -- for…