Source: http://bc-injury-law.com/blog/tag/causation
Timestamp: 2019-04-19 18:44:55+00:00

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The BC Court of Appeal released reasons for judgement this week further addressing the law of indivisible injuries.
In this week’s case (Moore v. Kyba) the Plaintiff was member of the Canadian Navy and suffered an interscapular injury in a 2007 motor vehicle collision. A year before this he injured his right shoulder in a shipboard fall and lastly suffered a bicep tear during a fall in 2008.
 Much judicial ink has been spilled concerning the characterization of multiple injuries as divisible or indivisible, and the impact of that characterization on the determination of causation and assessment of damages in a negligence case.
 The legal principles underlying these concepts are clear, but explaining them to a jury “is no easy task” (see Laidlaw v. Couturier, 2010 BCCA 59 at para. 40). Nor is their application in varying particular factual contexts always straightforward.
 The relevant principles were clearly set out in Athey v. Leonati,  3 S.C.R. 458. Their elaboration in Blackwater v. Plint, 2005 SCC 58,  3 S.C.R. 3, and by this Court in T.W.N.A. v. Canada (Ministry of Indian Affairs), 2003 BCCA 670 at paras. 22-37, B.P.B. v. M.M.B., 2009 BCCA 365, Bradley v. Groves, 2010 BCCA 361 and Laidlaw are also helpful.
It is important to distinguish between causation as the source of the loss and the rules of damage assessment in tort. The rules of causation consider generally whether “but for” the defendant’s acts, the plaintiff’s damages would have been incurred on a balance of probabilities. Even though there may be several tortious and non-tortious causes of injury, so long as the defendant’s act is a cause of the plaintiff’s damage, the defendant is fully liable for that damage. The rules of damages then consider what the original position of the plaintiff would have been. The governing principle is that the defendant need not put the plaintiff in a better position than his original position and should not compensate the plaintiff for any damages he would have suffered anyway: Athey.
 Thus, whether a defendant is liable to a plaintiff for an injury is a matter of causation; the amount of compensation the defendant must pay is a matter of assessment of damages.
The respondents submitted that apportionment is permitted where the injuries caused by two defendants are divisible (for example, one injuring the plaintiff’s foot and the other the plaintiff’s arm): Fleming, supra, at p. 201. Separation of distinct and divisible injuries is not truly apportionment; it is simply making each defendant liable only for the injury he or she has caused, according to the usual rule. The respondents are correct that separation is also permitted where some of the injuries have tortious causes and some of the injuries have non-tortious causes: Fleming, supra, at p. 202. Again, such cases merely recognize that the defendant is not liable for injuries which were not caused by his or her negligence.
In the present case, there is a single indivisible injury, the disc herniation, so division is neither possible nor appropriate. The disc herniation and its consequences are one injury, and any defendant found to have negligently caused or contributed to the injury will be fully liable for it.
 In this case, in determining causation, the jury had to determine whether the appellant caused injury to the respondent, and if so, whether the rotator cuff injury, the interscapular pain, and the bicep tear were divisible injuries or an indivisible injury. If they were divisible, the appellant could only be found to be liable for the interscapular pain caused by the motor vehicle accident. If they were indivisible, the appellant would be liable for that indivisible injury. ..
 At the stage of assessment of damages, the question is what compensation the plaintiff is entitled to receive from the defendant.
 If the injury is divisible, then the plaintiff is entitled to be compensated for the injury caused by the defendant. In this case, if the interscapular pain was a divisible injury, then the respondent was entitled to compensation for his loss flowing from that injury.
 For a recent example of a reduction in damages to reflect a pre-existing condition, see Bouchard v. Brown Bros. Motor Lease Canada Ltd., 2012 BCCA 331.
At the conclusion of the reasons the Court of Appeal attached the trial judge’s jury charge which is worth reviewing. For access to my archived posts addressing indivisible injuries you can click here.
Reasons for judgement were released this week by the BC Supreme Court, Kelowna Registry, discussing the issue of causation in a disc injury claim.
In this week’s case (Valuck v. Challandes) the Plaintiff was injured in a 2007 head-on collision. Fault was admitted by the offending motorist. The Plaintiff was ultimately diagnosed with a disc protrusion at the L5-S1 Joint.
ICBC argued the disc protrusion was not caused by the crash or if it was it would have occurred even in the absence of the collision. Mr. Justice Rogers disagreed and found that while it was not scientifically possible to say with certainty that the disc injury was caused by the crash, it certainly was an event that materially contributed to the injury.
 There is a conflict in the evidence concerning the cause of the herniation of the plaintiff’s lumbar disc at the L5-S1 joint. According to Dr. Laidlow, the plaintiff’s disc was probably not injured in the collision. He bases his opinion primarily on the fact that the plaintiff’s complaints of low back symptoms did not start until several weeks after the accident. According to Dr. Laidlow, if the disc had been damaged in the accident then the plaintiff would have had symptoms in that area right after the event and that she would not have been able to ignore those symptoms. According to Drs. Shuckett and Craig, the impact likely caused some damage to the plaintiff’s lumbar disc and that damage materially contributed to the herniation that the plaintiff subsequently experienced a year and a half later.
 I found Dr. Laidlow’s evidence to be particularly useful here. Dr. Laidlow said, and I accept, that a spinal disc comprises a containment vessel made up of fifteen to twenty layers of fibrous material and of viscous disc material lying within the containment vessel. The fibrous layers of the wall can, over time, suffer tears. The tears can be spontaneous or, rarely, they can be caused by trauma. The tears may heal over time, or they may not. Tears may occur without causing any symptoms at all. Enough tears may, at some point, be present in the disc wall so that the wall begins to fail. If that happens then the disc might bulge out. The bulging can intrude on pain sensitive tissues and pain may result.
 At some further point, enough tears may be present in the fibrous layers to compromise the wall itself and the wall breaks. In that event, the viscous inner disc material will escape from the disc. The escaped material is termed a protrusion and the condition is known as a herniated disc. The protrusion may impinge on surrounding tissues, causing local pain. The protrusion may also impinge on the nerve roots that exit the spine at the site of the hernia. In that case, symptoms usually include pain radiating along the area enervated by that particular nerve.
 Dr. Laidlow testified that an accident such as the one in which the plaintiff was involved would likely have caused damage of some kind to her spine. Dr. Laidlow was not willing to say for sure such damage included tears in the wall of the plaintiff’s lumbar disc. In his view, such damage was possible, but that he could not say for sure one way or the other. Given the several weeks’ delay between the trauma of the accident and the onset of the plaintiff’s low back pain, and the year and half that passed between the accident and the herniation, Dr. Laidlow felt that the accident could not be said to be a material contributing factor in the herniation.
 Although Drs. Schuckett and Craig did not say so in so many words, the gist of their evidence was that they thought that the accident probably did weaken the disc and thus materially contributed to the herniation that occurred on the Labour Day weekend of 2008.
 Dr. Laidlow cannot be faulted for testifying that there is no way to know if the accident in fact caused one or more tears to the wall of the plaintiff’s lumbar disc – no images exist to show the state of her disc in intimate detail immediately before or immediately after the accident, and no physical examination short of a biopsy could have illuminated that issue for him.
 After taking into account all of the medical evidence and the all of evidence of the plaintiff and her witnesses, and after applying a soupcon of common sense to the mix, I have concluded that the accident did cause some damage to the containment wall of the plaintiff’s L5-S1 disc and that that damage was a material contributing factor in the herniation that occurred at the end of August 2008. It follows that I find that the defendant is liable for damages caused by that herniation.
The BC Court of Appeal released reasons for judgment this week providing a short and useful summary of the law of causation in personal injury lawsuits.
 To justify compensation for his disabling pain, the plaintiff must establish a causal connection between the defendant’s negligence and that pain.
 The general test for causation, established in Athey v. Leonati,  3 S.C.R. 458 at paras. 13-17, is the “but for” test: “but for” the accident, would the plaintiff have suffered the disabling pain? In Athey, the Court also stated that a plaintiff need not establish that the defendant’s negligence was the sole cause of the injury. If there are other potential non-tortious causes, such as the plaintiff’s spinal degeneration in this case, the defendant will still be found liable if the plaintiff can prove the accident caused or materially contributed to the disabling pain, beyond the de minimus range.

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