On Feb. 20, 2016, claimant Ann Green, 62, a retiree, was driving in San Rafael. Her vehicle was broadsided by an underinsured motorist. Green claimed to her back. The other motorist’s insurer tendered its policy. Green sought further recovery via the supplementary-underinsured-motorist provision of her own insurance policy, which was administered by State Farm Insurance Cos. Green claimed that the other motorist was negligent in the operation of the other vehicle and caused the accident by running a red light. The matter proceeded to arbitration., Green claimed she suffered an aggravation of her preexisting lumbar condition as a result of the accident. She claimed that, following the incident, she had pain in her back, but she still continued on to a dinner party. She presented to a doctor one month later and was diagnosed with a herniated disc at the L5-S1 level. Green  underwent multiple steroid injections to her lumbar spine and graduated to radiofrequency nerve ablations. She ultimately underwent a transforaminal lumbar interbody fusion in 2020, four years after the accident. Green claimed the accident sped up the degeneration of her lumbar spine, causing severe pain and the need for the lumbar fusion. The plaintiff’s treating neurosurgeon testified about Green’s back surgery, and opined that the subject accident was a substantial factor in causing the need for Green to have the lumbar surgery. Green sought recovery of past medical costs and damages for past and future pain and suffering. State Farm’s counsel noted that Green did not seek medical treatment immediately after the accident and, instead, continued on to a party. Counsel also noted that Green did not see a doctor for almost one month. In addition, State Farm’s counsel noted that, during expert discovery, the parties learned that Green had fallen off of a horse in 2018, two years after the motor vehicle accident, and suffered fractures to her ribs and sacrum. State Farm’s counsel asserted that Green’s lumbar injury and subsequent surgery were a result of the fall from the horse and not related to the subject accident.