When a Plaintiff suffers injuries by the fault of another but the evidence establishes that the person would have likely suffered the same symptoms of pain because of a pre-existing condition the Plaintiff’s award of damages can be reduced to reflect this reality. This principle of personal injury law is known as the “crumbling skull” doctrine. Reasons for judgement were released this week by the BC Supreme Court, Vernon Registry, dealing with this area of law.
In this week’s case (Booth v. Gartner) the Plaintiff was injured in a 2007 BC car crash. The Defendant struck the Plaintiff’s vehicle when he entered an intersection against a red light. ICBC admitted fault on behalf of the Defendant but disputed the extent of the accident related injuries.
At trial Mr. Justice Cole found that the accident caused a variety of injuries. One of the most significant was low back pain which continued to the time of trial. The Plaintiff did not have back pain before the car crash however she had severe pre-existing (although asymptomatic) facet arthritis in her low back. The accident caused this condition to become painful. The Court was persuaded that this condition had a likelihood of developing pain in the future even without the accident. As a result of this finding the Court reduced the Plaintiff’s non-pecuniary damages by 25%. In reaching this result Mr. Justice Cole reasoned as follows:
 I accept Dr. Vallentyne’s opinion that the degeneration in her lower back is severe at two levels and it is likely she would have been troubled by lower back pain and stiffness at some time in the future, absent Accident #2. However, I am also satisfied that although the degeneration is pre-existing, there was symptomatic acceleration of the facet arthritis as a result of Accident #2…
 The CT scan of September 20, 2008, according to Dr. Vallentyne, “showed severe bilateral degeneration of the facet joints at the L4-5-S1 levels in addition to a minor 3 mm L4-5 degenerative anterolisthesis”.
 According to Dr. Vallentyne, degenerative changes take years to develop and he found it was probable that the plaintiff had degenerative changes of her lower lumbar facet joints prior to the 2007 motor vehicle accident. He concluded that “[g]iven that the degeneration is severe at two levels, it is likely that Ms. Booth would have been troubled by low back pain and stiffness at sometime in the future absent the 2007 MVA.”
 I am satisfied that there is a measurable risk that the pre-existing condition would have detrimentally affected the plaintiff in the future, regardless of the defendant’s negligence, and I must take that into account in reducing the overall award.
 The principle to be applied is found in Zaruk v. Simpson et al., 2003 BCSC 1748, 22 B.C.L.R. (4th) 43 [Zaruk]. There the plaintiff had suffered a soft-tissue injury but some of her symptoms by the time of trial were consistent with degenerative changes. The Court was not satisfied that the general condition would have become symptomatic between the date of the accident and the date of trial, but concluded at para. 40, that there was a measurable risk that it would have become symptomatic in the future:
 However, application of the crumbling skull doctrine may not result in the same reduction for past losses as future losses. Past losses must be assessed on the basis of a balance of probabilities. “Once the burden of proof is met, causation must be accepted as a certainty,” [Athey v. Leonati,  3 S.C.R. 458] ¶ 30). But for the assessment of future losses, “[a] future or hypothetical possibility will be taken into consideration as long as it is a real and substantial possibility and not mere speculation,” (Athey ¶ 27)
 The Court then reduced non-pecuniary damages by 15% and future care damages by 20%.
 Because the plaintiff’s degenerative condition was described by Dr. Vallentyne as “severe bilateral degeneration”, I am of the view that a large deduction is appropriate in this case and I find an appropriate deduction for non-pecuniary damages is 25% and for future care damages, 30%.
 In a crumbling skull situation, as in this case, the plaintiff has a pre-existing condition which is active, or likely to become active. The pre-existing condition “does not have to be manifest or disabling at the time of the tort to be within the ambit of the crumbling skull rule”: Barnes at para. 89, citing A. (T.W.N.) v. Clarke, 2003 BCCA 670, 22 B.C.L.R. (4th) 1 at para. 62. In crumbling skull situations, the defendant is only liable for damages caused by the accident and responsible for returning the plaintiff to their original position. As Major J. stated in Athey: the defendant is liable for the additional damage but not the pre-existing damage: at para. 35. The defendant is therefore not liable for the effects of the pre-existing condition that the plaintiff would have experienced in any event: A. (T.W.N.) at para. 52. If there is a “measurable risk” that the pre-existing condition would have impacted the plaintiff in the future then, regardless of the defendant’s negligence, a court can take this into account in awarding damages: at para. 35.
 In addition, the defendant claims an independent intervening event, subsequent to the Accident, also had significant impact on the plaintiff. An independent intervening event is an unrelated event, such as disease or a non-tortious accident, that occurs after the plaintiff is injured. The impact of such events is taken into account in the same manner as pre-existing conditions: Barnes at para. 96. Thus, the plaintiff is only entitled to damages which flow from the difference between his or her original position and their “injured position”: Athey at para. 32. If the unrelated event would have impacted the plaintiff’s original position adversely, the “net loss” attributable to the accident at issue will not be as great and damages will be reduced proportionately: Barnes at para. 96.
 I note that our Court of Appeal has stated that a reduction in damages to reflect the impact of independent intervening events or pre-existing conditions applies equally to non-pecuniary and pecuniary damages: A. (T.W.N.) at paras. 36-37; Barnes at para. 90.