SCC to review standard of care and causation issues in medical negligence suits

How does a patient who suffered an unforeseen injury during surgery prove that their surgeon was negligent? Can the injury itself provide circumstantial evidence that the standard of care was breached? Or must the plaintiff first disprove all possible non-negligent causes of the injury?

The Supreme Court of Canada (“SCC”) will consider these issues on January 18th when it hears the case of Karen Armstrong v Colin Ward, SCC 39049.

The Facts

In February 2010, Karen Armstrong (“Ms. Armstrong”) underwent a colon removal procedure (“colectomy”) at the Royal Victoria Hospital in Barrie, Ontario. Her surgery was conducted by Dr. Colin Ward (“Dr. Ward”). There was no sign that Ms. Armstrong was injured during or immediately following the procedure. However, she later developed abdominal pain and doctors determined that her left ureter (which carries urine from the kidneys) was blocked by scar tissue. Ms. Armstrong eventually had to have her left kidney removed in October 2010 due to the damage caused by this injury. She sued Dr. Ward for negligence, alleging that he caused the scarring by improperly using a cauterizing device known as a LigaSure during her colectomy. She also sued the hospital and three other doctors, but eventually discontinued proceedings against all but Dr. Ward.

Ontario Superior Court of Justice

In Armstrong v Royal Victoria Hospital, 2018 ONSC 2439 (“Trial Decision”), Justice Mulligan held that Dr. Ward negligently caused Ms. Armstrong’s injuries. There were two issues during the seven-day trial. First, Did Dr. Ward breach the standard of care expected of a general surgeon in conducting Ms. Armstrong’s colectomy? Second, if so, did this breach cause the damage to Ms. Armstrong’s ureter?

The parties called two medical experts each. All the witnesses agreed that the LigaSure could cause damage through “heat transfer” up to two millimeters from the jaws of the tool. In order to avoid injury during a routine colectomy, a surgeon must identify the location of the ureter at the outset and regularly re-identify it throughout the procedure. Colectomies are common and the medical literature suggests that ureteral injuries during such surgeries are extremely rare. Based on this evidence, Justice Mulligan concluded that the standard of care required of a general surgeon performing a colectomy is to identify, protect, and avoid direct contact with or close proximity to the ureter with the LigaSure.

Ms. Armstrong argued that Dr. Ward breached this standard either by directly injuring her with the Ligasure or improperly bringing it within two millimeters of her ureter. Justice Mulligan found that Dr. Ward did not directly touch the ureter with the LigaSure because this would have caused different symptoms than occurred. He also accepted that Dr. Ward initially took steps to identify and protect the ureter. However, Justice Mulligan rejected Dr. Ward’s claim that he always kept at least five centimeters away at all times, in part because the ureter was not always in view of his surgical camera.

Instead, Justice Mulligan inferred that Dr. Ward had brought the LigaSure within two millimeters of Ms. Armstrong’s ureter and so breached the standard of care. In reaching this conclusion, he gave weight to the plaintiff’s expert evidence that Ms. Armstrong’s injury could not have occurred in a routine colectomy but-for the defendant’s negligence. The expert testified that, were the appropriate steps carried out, the risk of damaging the ureter “should be zero” (Trial Decision, para 75). In contrast, the defence expert’s theory was that the LigaSure had either set off some sort of inflammatory response, or caused collateral damage to surrounding fatty tissue, that led to the scarring. Justice Mulligan found no other supporting evidence for this theory. Furthermore, the LigaSure is a ubiquitous, precision-based device. Justice Mulligan accepted that if it had such a serious side effect, then not only would higher rates of reported injury be expected, but surgical use of the LigaSure would have been discontinued.

Ontario Court of Appeal

Dr. Ward appealed from the trial judgment. In Armstrong v Royal Victoria Hospital, 2019 ONCA 963 (“Appeal Decision”), a majority of the Ontario Court of Appeal set aside the lower court’s finding of negligence.

The Majority

Justice Paciocco held that the trial judge had erred in imposing a “standard of perfection” on Dr. Ward rather than one of reasonable care (Appeal Decision, para 3). This standard improperly emphasized the goal of the surgery (i.e., not to injure the ureter) rather than the steps that a reasonably prudent surgeon would take to achieve that result. Justice Paciocco felt that the trial judge had collapsed the causation and standard of care inquiries because liability appeared to flow merely from the fact that an injury occurred. In the majority’s view, Justice Mulligan also failed to identify the steps required of a reasonably prudent surgeon in a colectomy beyond those he found that Dr. Ward took in this case. Justice Paciocco disagreed that keeping the LigaSure more than two millimeters away from the ureter was itself a step because the standard provided that any such deployment, whether intentional or accidental, was improper. This was too high a standard that amounted to a requirement to avoid all injuries.

The majority accepted that a goals-based approach might be acceptable in extreme cases, such as leaving a surgical implement inside a patient or removing the wrong limb. However, a trial judge cannot conclude that only negligence could have caused an injury without first ruling out potential non-negligent causes. The defendant does not have the burden to raise these other explanations. This was not such an extreme case because Justice Mulligan did not explicitly find that it would always be negligent to deploy a LigaSure within two millimeters of the ureter. He could not use success as the standard of care if there might be accidental but non-negligent deployment of the tool.

The Dissent

Justice van Rensburg would have maintained the trial decision. In a lengthy dissent, she disagreed that the trial judge had articulated a standard of perfection or adopted a results-oriented approach. In her view, the evidence clearly supported the conclusion that a reasonably competent surgeon would have kept the LigaSure at least two millimeters away from the ureter at all times. This was an essential step of the procedure rather than a goal outside of the surgeon’s control. The ultimate objective was not protection of the ureter but rather safe removal of the colon. Contrary to the majority’s characterization, the trial judge found that Dr. Ward failed to take all steps required to protect the ureter throughout the entire surgery.

The dissent further held that for a plaintiff to succeed in a medical malpractice case, they are not required to disprove every possible explanation for an injury—especially not theories that are never raised at trial. Similarly, a trial judge need only consider potential non-negligent causes that are actually supported by the evidence. In this case, the central trial inquiry was how Ms. Armstrong’s injury had occurred. The trial judge explicitly considered, and rejected, the defendant’s theory of non-negligent cause. By speculating about other potential explanations, the majority inappropriately considered theories that were not supported by the record.

Key Issues on Appeal

Deference to Factual Findings

The majority of the Court of Appeal described Justice Mulligan’s standard of care determination as “an error of law” (Appeal Decision, para 33). However, as the dissent points out, the lower court’s inquiry was heavily fact-based. On appeal, Ms. Armstrong argues that the majority effectively re-weighed the trial evidence and so failed to defer to trial judge’s findings of fact.

Defining the Standard of Care

If Justice Paciocco was concerned that the trial judge set too high a standard for surgeons, the majority decision may take the law in the opposite direction. An unfortunate implication of the judgment is that a surgeon can apparently meet their duty of care by taking some, but not necessarily all, of the required steps in medical procedure. However, as Justice van Rensburg noted, “[t]here is a difference between using the appropriate technique and executing it properly” (Appeal Decision, para 165).

In this case, all of the experts agreed that avoiding the ureter is a central requirement of a colectomy. They disagreed primarily over how Ms. Armstrong’s injury occurred and whether bringing the LigaSure within two millimeters of the ureter would be a breach of the standard of care. The trial judge weighed this evidence and sided with the plaintiff’s experts. In his appeal factum, Dr. Ward suggests that ureteral injuries are a normal complication of colectomies (Respondent’s Factum, para 105). Yet the trial evidence indicated the opposite. It seems reasonable to conclude that the minimum standard here was more than merely trying to avoid the ureter, but instead actually avoiding it.

Injury as Circumstantial Evidence of Breach

The majority’s distinction between goals and steps may be semantic since, as Ms. Armstrong argues, virtually every aspect of a surgery could be described as either one. But the majority was also concerned that the trial judge inferred a breach of the standard of care simply because Ms. Armstrong had experienced an injury. In contrast, the dissent found that determining whether a breach occurred required first deciding what actually happened during surgery. There were competing theories of whether the injury in this case was the result of Dr. Ward bringing the LigaSure within two millimeters of Ms. Armstrong’s ureter, or him keeping his distance but nevertheless causing inadvertent scarring. Causation therefore bore directly on whether Dr. Ward maintained an appropriate distance. The trial judge inferred that he had not done so because the evidence did not support the defence explanation for the injury. Dr. Ward criticizes this as an example of hindsight bias in the negligence analysis. For her part, Ms. Armstrong argues that, “there was simply no evidence that a surgeon could take reasonable precautions and nevertheless come with[in] 2mm of the ureter” (Appellant’s Factum, para 78). If the trial judge correctly articulated the standard of care, then it seems this inferential approach was necessary due to the lack of direct evidence about the surgery.

Disproving Non-Negligent Causes of Injury

The plaintiff has the burden to prove all elements of a negligence claim on a balance of probabilities. But expecting a patient to specify how a doctor was negligent may create an imbalance since they usually cannot know exactly what happened during surgery. As in this case, the defendant—a medical expert who actually conducted the procedure—can easily claim ignorance of how the injury occurred.

Both Ms. Armstrong and the intervenors at the SCC argue that where the plaintiff establishes prima facie causation, they should succeed unless the defendant can demonstrate an equally likely, non-negligent cause of the injury. This is consistent with Justice van Rensburg’s holding that the causation analysis should be limited to those theories actually raised at trial. While the plaintiff retains the legal burden, the defendant will have a tactical burden to raise non-negligent explanations (and the plaintiff will face a further decision over whether and how to rebut those arguments). This framework appears better calibrated to the complexities of medical causation than the majority’s standard. Proving that only negligence could have caused an injury will be an impossible hurdle in many cases.

Ultimately, it is difficult to predict how the Court will decide these interrelated issues on appeal. Whatever the result, this case is one to watch due to its implications for the medical malpractice bar and negligence claims more broadly.

Erin Sobat

Erin Sobat

Erin Sobat is a third-year JD student at Osgoode Hall Law School. He previously completed a Bachelor of Arts in History at McGill University. At Osgoode, Erin spent eight months as a Workers’ Rights caseworker at Parkdale Community Legal Services. He has also been actively involved with Osgoode’s chapter of the Law Union of Ontario, the Journal of Law and Social Policy, and various other legal aid clinics. Erin will be articling at a union-side labour law firm in Toronto. Outside of law, he enjoys cooking, biking, and reading science fiction on his balcony.

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