by Rozmin Mediratta February 08, 2021 4 min read

The test for the standard of care in medical negligence cases has remained untouched since the Supreme Court of Canada’s 1995 decision in ter Neuzen v. Korn.

On January 18, 2021, the Supreme Court of Canada heard the appeal in Armstrong v. Ward. Their unanimous decision maintains the status quo with respect to the standard of care in medical negligence cases.


The action was brought by the plaintiff Karen Armstrong who underwent a surgical procedure to remove her colon (a “colectomy”). While the surgery itself seemed uneventful, Ms. Armstrong developed postoperative issues, including abdominal pain and a pulling sensation. It was determined that her left ureter was blocked by scar tissue, and her left kidney was eventually removed as a result.

Ms. Armstrong sued Dr. Colin Ward, who performed the surgery, as well as the hospital and 3 other physicians. By the time of trial, she had discontinued her claim as against all defendants except Dr. Ward.

The only issue at trial was liability. Ms. Armstrong alleged that Dr. Ward was negligent in that he either touched her left ureter with the cauterizing device or brought it too close to the ureter causing injury. When the injury healed, the scarring caused the blockage.

It was undisputed that the injury occurred. It was common ground amongst the parties’ experts that heat emitting from the cauterizing device is capable of damaging tissue within 2mm, and that surgeons should identify the position of the ureter and stay at least 2mm away from it.

Dr. Ward’s position was that he stayed at least 5mm away from the ureter during the surgery, and his experts provided alternative explanations for the injury. Dr. Ward further argued that even if he accidentally came within 2mm of the ureter, he met the standard of care because he followed all of the steps in the procedure, including taking steps to identify and protect the ureter.

Ms. Armstrong’s position was that had Dr. Ward followed all of the steps in the procedure (which were undisputed), the chances of an injury to the ureter would have been zero.

In the end, the trial judge accepted Ms. Armstrong’s position that the cauterizing device caused the injury – the inference being that Dr. Ward used the device within 2mm of the ureter and therefore breached the standard of care.

The Ontario Court of Appeal

Dr. Ward appealed the trial judge’s decision.

In a 2-1 decision, the majority of the Ontario Court of Appeal the trial judge improperly applied a standard of perfection and a results based approach. In doing so, they explained that staying away from Ms. Armstrong’s ureter was the “goal” of the surgery, and that the trial judge failed to consider what reasonable “steps” were required in order to achieve that goal. In other words, the goal does not define the standard of care, conduct does.

Unsurprisingly, there were exceptions to the rule. The majority wrote that a results based approach to defining the standard of care is appropriate where negligence alone could prevent a goal from being achieved or a positive result from being attained, such as when a surgical instrument is left inside a patient or the wrong limb is removed. However, a trial judge must rule out all non-negligent causes in order to conclude that only negligence could have caused the outcome. The trial judge in this case did not do so and the appeal was allowed.

While the trial judge’s error of applying the improper standard of care was enough to allow the appeal, the majority went on to address Dr. Ward’s second ground of appeal (he had four), writing that the trial judge had improperly conflated the standard of care and causation analysis by inferring that Dr. Ward breached the standard of care by coming within 2mm of the ureter with the cauterizing device because there was an injury.

The Supreme Court of Canada

Ms. Armstrong appealed the Ontario Court of Appeal’s decision. The Supreme Court of Canada allowed her appeal, adopting the dissenting opinion of Justice van Rensburg of the Ontario Court of Appeal, and restored the trial decision.

In her dissenting opinion, Justice van Rensburg agreed there are dangers associated with a results oriented approach, but that the expert evidence at trial demonstrated staying away from the ureter was a “step” not a “goal”. She further stated that “[t]here is a difference between using the appropriate technique and executing it properly”, and that there was no evidence to suggest that a competent surgeon using reasonable care would be unable to stay more than 2mm away from the ureter during a colectomy.

She went on to write that trial judges are not required to consider potential non-negligent causes not put forward at trial, and that in this case, the trial judge considered and rejected the non-negligent causes put forward by Dr. Ward. Moreover, while the burden of proof stays with the plaintiff, they are not required to disprove every theory that could be put forward by a defendant, and particularly not ones not put forward at trial.

Finally, Justice van Rensberg agreed with the majority that it typically makes sense for a trial judge to consider causation after standard of care but that sometimes the court will need to determine what happened in order to resolve whether the standard of care was met. The case at bar fell into the latter category.

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