Implications of the Armstrong Decision for Medical Malpractice Litigation

The Armstrong v. Ward, 2021 SCC 1 (“Armstrong”) case is of critical importance to plaintiffs, particularly plaintiffs in medical malpractice lawsuits. This case will undoubtedly have major implications for medical malpractice litigation going forward.

Facts and Legal Principles

The plaintiff in this case, Karen Armstrong, underwent a laparoscopic colectomy in 2010. Following the surgery, the plaintiff developed an obstructed ureter that led to further significant health complications.

In a typical medical malpractice case, in order to succeed in proving negligence, a plaintiff must show that:

  1. The defendant physicians and/or nurses breached the applicable standard of care; and,
  2. That the breach caused harm leading to compensable damages.

Generally speaking, standard of care is defined as the level of care that is required of a professional, with the same training, education and experience, as the defendant. In order to determine if a physician and/or nurse breached the standard of care, the plaintiff must adduce expert evidence, typically from a professional in the same specialty as the defendant(s).

Once a plaintiff overcomes the first part of the negligence test, then they must prove that the breach in fact caused physical and/or psychological harm. If a physician and/or nurse breached the standard of care but the breach did not cause any harm, then the plaintiff would not have any compensable damages.

In Armstrong, the surgeon, Dr. Colin Ward, used a LigaSure (which was the standard instrument to use for this procedure) to perform the colectomy. A LigaSure is a tool that essentially passes an electronic current between two prongs, and is used to dissect and cauterize tissue.  A LigaSure uses heat to cauterize tissue, and therefore there is a small spread of thermal radiation from the device. The main issue in the case was whether the surgeon performed the procedure correctly.

The plaintiff’s lawyer argued that the standard of care required a surgeon to stay more than 2mm away from the ureter and that Dr. Ward used the LigaSure within 2mm of Ms. Armstrong’s ureter which led to her injury. The defence argued that Dr. Ward stayed more than 5cm away from the ureter and that Ms. Armstrong’s injury was not the result of anything that Dr. Ward did, but rather an unavoidable consequence of using the LigaSure device.

Procedural History

At trial, the Judge found that the standard of care required the surgeon to keep the device more than 2mm from the ureter. He concluded that because the ureter was injured, the defendant had failed to stay within the appropriate surgical margins. The defence appealed the Trial Judge’s decision to the Court of Appeal for Ontario and the appeal was allowed.

In its 2019 decision, the majority for the Court of Appeal held that it is not enough for a plaintiff to frame the standard of care, but that a plaintiff must outline the specific steps a physician must follow to determine whether there was a breach. The Court of Appeal also noted that the Trial Judge failed to exclude other non-negligent causes (for example that a surgeon’s hands may shake during a procedure) that could lead to an injury. It is important to note that the Court of Appeal highlighted this, despite the fact that the defence did not produce any evidence on such causes. The majority also noted that the Trial Judge incorrectly applied a results-oriented analysis: finding that if the ureter was injured, then the defendant must have failed to adhere to the surgical margins.

Justice van Rensburg of the Court of Appeal wrote a strong dissent to the majority’s decision. She noted that a Trial Judge has no obligation to consider potential causes that are not advanced by the parties. In fact, if this were permitted, it could lead to multiple errors, since parties generally will review all possible factors but will only raise those causes that are possible based on the medicine.  Another important point raised by Justice van Rensburg was her finding that the Trial Judge did not err in conducting a causation analysis by first analyzing the outcome in order to determine if a breach took place.

The Plaintiff sought leave to the Supreme Court of Canada and in 2021, the Court ultimately adopted Justice van Rensburg’s reasoning, and once again found that Dr. Ward had been negligent.


The Supreme Court of Canada’s decision in the Armstrong case provides essential guidance on several points of law. Two of the most important developments are the Court’s clarification of the guidance regarding the application of ‘standard of care,’ and its revival of the evidentiary doctrine of ‘res ipsa loquitur.

Armstrong confirms that a defendant physician’s intention to meet the standard of care is simply not enough. The defendant must actually execute the necessary steps appropriately. If the Court of Appeal decision was upheld, then a surgeon would essentially have a blanket defence in multiple cases. In other words, a surgeon could argue that he or she intended to take the required steps but they were simply not successful. This would be an impossible defence for plaintiffs to overcome.

In addition, one of the most significant principles to come out of the Armstrong case is the Court’s guidance on the doctrine of res ipsa loquitur which means “the thing speaks for itself.” Before 1998, this doctrine was applied to occurrences (a) that would not have happened without negligence, and (b) where there was no evidence as to why or how the occurrence took place.  In other words, it was used in cases where the facts permitted an inference of negligence based on circumstantial evidence. However, in the case of Fontaine v. British Columbia (Office Administrator), 1998 (“Fontaine”), the Supreme Court of Canada held that the doctrine of res ipsa loquitur should be treated as “expired.”

With the Armstrong decision, the Supreme Court of Canada has essentially revived this doctrine. In this particular case, the circumstantial evidence was the nature of the actual injury that was caused to Ms. Armstrong. There was no evidence to suggest that a surgeon who actually met the standard of care would be unable to stay more than 2mm from the ureter. Armstrong confirms that a Trial Judge is entitled to determine what actually happened in order to determine whether the requisite standard of care was met. Armstrong tells us that this does not mean that the judge or jury is conflating standard of care and causation or applying the negligence test in the wrong order.

Prior to Armstrong it would be very difficult for a personal injury lawyer to take on a medical malpractice case where they would have to rely heavily on circumstantial evidence. Following this new precedent, lawyers will be able to build their theories of negligence knowing that, where appropriate, both direct and circumstantial evidence can be considered. While this development does not make it easier to prove negligence, or change the requirements for proving a breach in the standard of care, it will perhaps open the door for more patients who have been harmed while receiving medical treatment to pursue justice.

Samantha Shatz practices personal injury law with a focus on Medical Malpractice claims. Samantha helps patients and their families who have been harmed as a result of negligence by physicians and health care institutions. She can be reached at 647-796-0086 or

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