It is not enough at law for a Plaintiff to prove that a defendant is negligent, as a Plaintiff must also prove that the negligence of a Defendant actually caused the injury.

 

The general, but not conclusive, test for causation is the “but for” test. A Plaintiff must show, on a balance of probabilities, that “but for” (without) the negligence of the Defendant, then the Plaintiff’s injury would not have happened.

 

The “but for” test is not workable in some situations, so courts also establish causation where the negligence of the Defendant “materially contributes” to the occurrence of the injury i.e. beyond the de minimus range.

 

The “but for” test also recognizes that compensation for the negligence of another should only be made where there is a substantial connection between the injury and the conduct of the Defendant.  This ensures that the Defendant will not be held liable for a Plaintiff’s injuries when such injuries may be due to factors that are not connected to the Defendant.

 

There is no requirement for a Plaintiff to show that the negligence of a Defendant was the sole cause of the injury to the Plaintiff. So long as the defendant was only part of the cause of an injury, then that Defendant will be liable, even if his or her act alone was not enough to cause the injury to the Plaintiff. The Defendant is responsible for all injuries substantially connected to, or caused by, the negligence of the Defendant.

 

In Perry v. Vargas, the Plaintiff was injured in a motor vehicle accident, and brought an ICBC claim for injuries. There were several other non-tortious (not related to the car accident) causes of the Plaintiff’s injuries as well. The Court would eventually rule that, based on a preponderance of probabilities, it was not prepared to find that the motor vehicle accident was the cause of the Plaintiff going from working full-time, to not being able to work full-time. The Court also provides useful commentary on the relevant principles of law with respect to the issue of causation.

 

[103]     In Resurfice Corp. v. Hanke, 2007 SCC 7 (CanLII), 2007 SCC 7 at paras. 21 to 23, 2007 SCC 7 (CanLII), [2007] 1 S.C.R. 333, the Supreme Court of Canada confirmed that the basic test for determining causation remains the “but for” test, and that the test applies to multi-cause injuries. However, the Court developed the “but for” test by stating a “substantial connection” between the injury and the defendant’s conduct is necessary in cases where the defendant’s act was not the sole cause of the plaintiff’s injury. 

 

[104]     The developments in the “but for” test in Hanke were succinctly summarized by Madam Justice Neilson in Farrant v. Laktin, 2011 BCCA 336 (CanLII), 2011 BCCA 336 at paras. 9 to 11, 338 D.L.R. (4th) 527

 

[9]  The general test for causation, established in Athey v. Leonati …….   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.

 

[10] In Hanke v. Resurfice Corp., 2007 SCC 7 (CanLII), 2007 SCC 7, [2007] 1 S.C.R. 333, …  the Court replaced the Athey definition of “material contribution” to the plaintiff’s injury with the concept of “a substantial connection” between the injury and the defendant’s conduct. These developments were usefully summarized by Mr. Justice Smith, writing for the majority, in Sam v. Wilson, 2007 BCCA 622 (CanLII), 2007 BCCA 622 at para. 109: 

 

… the “material contribution test” applies as an exception to the “but for” test of causation when it is impossible for the plaintiff to prove that the defendant’s negligent conduct caused the plaintiff’s injury using the “but for” test, where it is clear that the defendant breached a duty of care owed the plaintiff thereby exposing the plaintiff to an unreasonable risk of injury, and where the plaintiff’s injury falls within the ambit of the risk. …

 

[11] Thus, in applying the “but for” test, the trial judge was required to consider not just whether the defendant’s conduct was the sole cause of the plaintiff’s disabling pain, but also whether the plaintiff had established a substantial connection between the accident and that pain, beyond the de minimus level.

 

[Emphasis added.]

 

[105]     Accordingly, to satisfy the “but for” test, a plaintiff must show that the defendant caused his or her injury by proving on a balance of probabilities that the defendant’s conduct was the sole cause of his or her injury, or that there was a substantial connection between the defendant’s actions and the injury, beyond the de minimus level.

 

[145]     In short, I am not satisfied on a balance of probabilities that, but for the 2006 Accident, Ms. Perry would be having these ongoing symptoms. Nor am I satisfied that the debilitating headaches she experienced shortly before going on medical leave are related to the 2006 Accident. In my view it has not been proven, on a balance of probabilities,  that her change from being capable of full-time work to being incapable of full-time work, occurring two years after the 2006 Accident, is related to any of the injuries she suffered in the 2006 Accident.   

 

In Valuck v. Challandes, the Plaintiff was injured in a motor vehicle accident in 2007, and later suffered a herniated disc in 2008, but not in a motor vehicle accident. At issue was whether the original accident in any way caused the herniated disc injury to occur. The Court ruled that the first accident caused some damage to the disc in question, which weakened the disc, and made it more susceptible to later injury. The Court commented that scientific precision is not necessary to establish causation.

 

[57]         The law is well settled that if the evidence shows on the balance of probabilities that a defendant’s tortious act materially contributed to the plaintiff’s pre-trial loss, then the defendant must be held liable for that loss. That is so even though the tortious act was only one of several non-tortious factors that caused the loss. This is a question of liability. So, when it comes to the intertwining of a tortious act and non-tortious conditions, the court must decide whether the defendant is liable or not liable. The law permits no middle ground.

 

[58]         In the present case the evidence clearly established that the collision caused injuries to the plaintiff’s chest, left shoulder, neck and mid-back. The defendant is liable for plaintiff’s losses attributable to those injuries.

 

[59]         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.

 

[60]         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.

 

[61]         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.

 

[62]         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.

 

[63]         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.

 

[64]         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.

 

[65]         I have concluded that the evidence in this case does not admit a scientifically certain answer to the herniation question. Scientific certainty is not necessary, however. As the Supreme Court of Canada said in Athey v. Leonati, [1996] 3 S.C.R. 458 at paragraph 16:

 

…Causation need not be determined by scientific precision; as Lord Salmon stated in Alphacell Ltd. v. Woodward, [1972] 2 All E.R. 475, at p. 490, and as was quoted by Sopinka J. at p. 328, it is “essentially a practical question of fact which can best be answered by ordinary common sense”. …

 

[66]         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.

 

In Farrant v Latkin, the British Columbia Court of Appeal discussed the law of causation in the context of personal injury lawsuits. The Plaintiff had suffered from pre-existing conditions, which were aggravated by a motor vehicle accident. At the trial level, the Plaintiff had argued that the ongoing symptoms were related to the motor vehicle accident in question, however the Court did not accept this. The Plaintiff successfully appealed, with the Court of Appeal finding that the trial judge had applied the wrong legal test for causation. A new trial was ordered.

 

[2]               The plaintiff had a history of back problems between 1976 and 1998, resulting in significant degenerative changes in his spine, which I will refer to as “spinal degeneration”. His back had been minimally symptomatic, however, in the six years preceding the accident. He suffered soft tissue injuries and a recurrence of his back pain in the collision, which were diagnosed as a Grade 2 whiplash. This improved substantially by July 2004 but, in the fall of 2004, the plaintiff’s back pain became more pronounced. It increased over the ensuing months and by April 2006 he was permanently disabled and could no longer work.

 

[3]               At trial, the defendant conceded the plaintiff’s back pain in the months immediately following the accident was caused by the collision. The central issue was whether the plaintiff could establish a causal connection between the accident and his subsequent and more debilitating back pain, which I will refer to as the “disabling pain”. The trial judge framed the issue in these terms:

 

[10]      The threshold issue in this case is causation: was it the injury sustained in the accident that caused, and continues to cause, the plaintiff’s back and leg pain, or is his pain attributable to his pre-existing degenerative disease of the spine?

 

[4]               The trial judge decided the plaintiff had not established the accident caused the disabling pain. He found the plaintiff’s whiplash had resolved for the most part in four months, and awarded $20,000 for that injury.

 

[5]               The plaintiff says the trial judge erred by casting the issue of causation as an either/or choice between the accident and his pre-existing spinal degeneration. He maintains that, in asking the wrong question, the trial judge failed to recognize that a plaintiff need not prove the defendant’s conduct was the sole cause of his or her injury. That error led him to neglect the alternative: that the accident and the spinal degeneration were both contributing causes of his disabling pain.

 

[6]               The defendant responds that the reasons for judgment of the trial judge, read as a whole, demonstrate he properly applied the governing law on causation, and his findings on that issue turned on an assessment of conflicting medical evidence that is abundantly supportable.

 

[7]               For the reasons that follow I would allow the appeal and direct a new trial.

 

[8]               To justify compensation for his disabling pain, the plaintiff must establish a causal connection between the defendant’s negligence and that pain.

 

[9]               The general test for causation, established in Athey v. Leonati, 1996 CanLII 183 (SCC), [1996] 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.

 

[10]           In Resurfice Corp. v. Hanke, 2007 SCC 7 (CanLII), 2007 SCC 7, 1 S.C.R. 333, the Supreme Court affirmed the “but for” test remains the basic test for determining causation, but developed the concept of “material contribution” in a different manner than that used in Athey, formulating a “material contribution” test as an exception to the “but for” test, a matter that is not relevant to this appeal. The Court replaced the Athey definition of “material contribution” to the plaintiff’s injury with the concept of “a substantial connection” between the injury and the defendant’s conduct. These developments were usefully summarized by Mr. Justice Smith, writing for the majority, in Sam v. Wilson, 2007 BCCA 622 (CanLII), 2007 BCCA 622 at para. 109:

 

“Material contribution”, as that phrase was used in Athey v. Leonati, is synonymous with “substantial connection”, as that phrase was used by McLachlin C.J.C. above in Resurfice Corp. v. Hanke.  This causal yardstick should not be confused with the “material contribution test”.  As McLachlin C.J.C. explained in Resurfice Corp. v. Hanke, at paras. 24 – 29, the “material contribution test” applies as an exception to the “but for” test of causation when it is impossible for the plaintiff to prove that the defendant’s negligent conduct caused the plaintiff’s injury using the “but for” test, where it is clear that the defendant breached a duty of care owed the plaintiff thereby exposing the plaintiff to an unreasonable risk of injury, and where the plaintiff’s injury falls within the ambit of the risk. …

 

[11]           Thus, in applying the “but for” test, the trial judge was required to consider not just whether the defendant’s conduct was the sole cause of the plaintiff’s disabling pain, but also whether the plaintiff had established a substantial connection between the accident and that pain, beyond the de minimus level.

 

In Skinner v Fu, the Plaintiff’s claim was dismissed at trial, however the British Columbia Court of Appeal ordered a new trial, ruling that the trial judge had failed to use the “but for” test of legal causation.

 

[16]         I now turn to the legal test to establish causation.  In Resurfice Corp. v. Hanke, [2007] 1 S.C.R. 333, 2007 SCC 7, the Supreme Court of Canada reaffirmed that the default test to establish causation in a negligence analysis remains the “but for” test.  The question is whether, but for the defendant’s breach of the standard of care, would the plaintiff have suffered damage?  At para. 21 of Resurfice, the Chief Justice said:

 

First, the basic test for determining causation remains the “but for” test.  This applies to multi-cause injuries.  The plaintiff bears the burden of showing that “but for” the negligent act or omission of each defendant, the injury would not have occurred.  Having done this, contributory negligence may be apportioned, as permitted by statute.

 

[17]         The Supreme Court’s articulation of the “but for” test might usefully be contrasted with the judge’s analysis, in this case, in which he posed the following question at para. 9:

 

… In determining the issue of liability for the accident, I must determine whether the negligence of the defendant was the proximate cause or materially contributed to the occurrence of the collision.

 

[18]         In my view the judge erred in the way he framed the analysis.  “Proximate cause” or “effective cause” are sometimes confusing terms.

 

[19]         The use and misuse of the term “proximate cause” was discussed by Smith J.A. in Chambers v. Goertz, 2009 BCCA 358, 275 B.C.A.C. 68 at para. 29:

 

Proximate cause” is a phrase ill-suited to the task of identifying culpable causes in negligence.  It implies that the law recognizes only one cause and that this sole cause must be close in time and space to the event.  As I have explained, these implications are not correct – every event has multiple historical factual causes.  The phrase “proximate cause” is most often used in tort law synonymously with “remoteness”, that is, “to inject some degree of restraint on the potential reach of causation”: R. v. Goldhart, at para. 36.  It suggests a limit on the scope of liability.  There is also a doctrine of proximate cause in insurance law, where the term has been used to signify the main or dominant or effective cause of a loss, since the insurer has contracted to pay for the loss only if, or unless, it was caused by an event specified in the insurance policy.  It must be noted that the term’s usefulness in insurance law has also been questioned: see C.C.R. Fishing Ltd. v. British Reserve Insurance Co., [1990] 1 S.C.R. 814 at 823, 69 D.L.R. (4th) 112, [1990] 3 W.W.R. 501; Derksen v. 539938 Ontario Ltd., 2001 SCC 72, [2001] 3 S.C.R. 398 at para. 36, 205 D.L.R. (4th) 1.

 

[20]         The judge’s use of the term “proximate cause” in this case, diverted the analysis from the correct approach, the “but for” test.  The judge must have employed a last clear chance analysis when he used the term “proximate”.  That term implies a finding of no liability based on a determination that the appellant could have entirely avoided the accident if only he had been more attentive to the road ahead of him.  The judge found that the defendant was negligent.  Indeed he could hardly have found otherwise.  The respondent did create an unreasonable risk of harm by remaining stationary in the way he did.

 

[21]         The judgment in Resurfice Corp. v. Hanke refines the test of causation and reminds us that the defendant’s breach of the standard of care need only be a cause of the plaintiff’s injury and not the sole cause (see also Athey v. Leonati, [1996] 3 S.C.R. 458).  There may exist other causes that materially contributed to the injury, but that does not relieve the defendant of liability.  In such circumstances, relief from liability follows only if the defendant’s breach of his standard of care did not materially contribute to the plaintiff’s injury.  The analysis should be focused on the question: “but for” the defendant’s breach of the standard of care, would the plaintiff have suffered damage?  Here the judge did use the term “materially contributed” at paragraph 9, as set out above, but I conclude that he used the term synonymously with “proximate cause”.  I reach this conclusion because he did not analyze the facts consistently with the Athey material contribution test but rather in the proximate or only one cause analysis that was criticized in Chambers.

 

[22]           In summary, it is my view that the judge erred by focusing his inquiry on the conduct of the appellant to the exclusion of the admitted negligence of the respondent.  That inquiry properly was one of apportionment, but the judge neglected the essential underlying inquiry into the respondent’s negligence, and whether it was connected causally to the appellant’s injury (Resurfice at para. 23).  The judge erred in failing to consider whether the respondent’s conduct created an unreasonable risk of harm and secondly, in failing to apply the “but for” analysis.  If he had done so, he would have had to conclude that the respondent’s breach of the reasonable standard of care was a cause of the accident. 

 

[23]           This is not to say that there is anything wrong with the generally accepted rule that following drivers will usually be at fault for failing to avoid a collision with a vehicle that has stopped quickly in front (Ayers v. Singh, 85 B.C.A.C. 307, [1997] B.C.J. No. 350).  Normally a sudden stop does not create an unreasonable risk of harm.  However, here the respondent’s act of remaining stationary, in the dark, on a well-traveled highway, where the speed limit was 90 kilometres per hour, without activating either brake lights or emergency flashers, did create an unreasonable risk of harm as that term was used by the Chief Justice in Lawrence. 

 

[24]           I would order a new trial because the necessary findings of fact that would enable this court to determine, and if necessary apportion, fault have not been made.

 

APPLYING PRINCIPLES of CAUSATION WHEN ASSESSING MEDICAL EVIDENCE

 

In Hunt v. Ugre the Plaintiff was injured in two separate motor vehicle accidents, and brought ICBC claims for damages. The Court would rule that the injuries from the two accidents were indivisible and, as such, apportionment of damages would not be necessary. The Court also had occasion to discuss how it would approach causation in the context of assessing medical evidence.

 

[122]     When assessing medical evidence how should the courts approach causation?  The Court in Tsalamandris v. MacDonald, 2011 BCSC 1138 (CanLII), 2011 BCSC 1138 at paras. 144-146 (var’d on other grounds, 2012 BCCA 239 (CanLII), 2012 BCCA 239), provides the following helpful formulation of the principles which inform the Court’s analysis:

 

Because the “but for” test is to be proved on a balance of probabilities, rather than a standard of scientific certainty, great care must be had in assessing medical evidence.  The human condition is incredibly complex.  The precise biological, biochemical or molecular mechanisms causing many medical conditions are often not known and may not be known for lifetimes to come, and for the same reason, prognosis and treatment is also often not certain.  In cases where medical causation cannot by its very nature be proven with certainty, medical experts may not be comfortable stating a black-and-white opinion as to what “caused” a patient’s condition.  Often medical evidence refers to known “risk factors” for medical conditions, or a number of causes, precisely because of the expert’s discomfort in assigning one “cause” to a complex medical issue.

 

In determining causation in the legal context, courts must be mindful to assess the import and substance of the expert opinion evidence, and to be cautious about the wording used by the experts so as to not unduly discount or over-weigh the expert’s choice of language when describing medical causation.  Ultimately causation is a question for the court, taking into account the evidence.

 

It is important for the court to keep in mind that all that is required to determine these complex medical issues in the context of causation is for the plaintiff to prove what is more likely than not.  This is what is meant by the “but for” test: it is more likely than not, that without the tort, the injury or medical condition would not have happened.

 

(emphasis added.)