On May 8, 2026, Paul presented at the Ontario Trial Lawyers Association’s 2026 Conference and Annual Meeting, held at the Metro Toronto Convention Centre, North Building. His paper, “Liability Considerations in Surgical ‘Never Events’ or Recognized Complication Cases,” addressed one of the most challenging areas of plaintiff-side medical malpractice practice: intraoperative surgical negligence, where the event in question occurred behind the closed doors of an operating room while the client was under general anesthesia.
The paper was built around the Supreme Court of Canada’s framework in Armstrong v Ward, 2021 SCC 1, [2021] 1 SCR 3, and around two of Paul’s own reported cases: O’Neill-Renouf v Ibrahim, 2019 ONSC 4369, in which the plaintiff succeeded, and Knight v Lawson, 2023 ONSC 570, in which the claim failed. The two cases, together with Armstrong, illustrate how surgical negligence claims succeed or fail on the evidentiary record.
The conceptual problem
Surgical negligence cases occupy a uniquely difficult space within medical malpractice law. Direct evidence of the alleged negligence is scarce. There is no eyewitness who can describe the precise moment of error. The operative report is often dictated hours later and reflects what the procedure was supposed to look like rather than a contemporaneous record of how it actually unfolded. The surgeon’s evidence at discovery and trial is typically a description of usual practice rather than specific recollection of the case.
Within intraoperative surgical claims, two categories of case recur in plaintiff practice. The first is “never events”: injuries that appear, on their face, to be inconsistent with competent surgical care. The second, far more challenging category, is “recognized complications”: adverse outcomes treated as accepted risks of properly performed procedures. The line between the two is often blurred. Cases that present initially as recognized complications can, on closer analysis, be reframed as never events once the mechanism of injury is properly understood.
The central legal challenge sits underneath that distinction. Negligence cannot be inferred from outcome alone. Yet outcome is often the most compelling, and sometimes the only, piece of evidence available to the plaintiff. The task is to turn outcome into inference, and inference into proof of substandard care.
Armstrong v Ward: the governing framework
The modern starting point is Armstrong v Ward. The trial judge had found liability where the defendant surgeon came within one to two millimetres of the ureter with a thermal device during a colectomy. The Court of Appeal for Ontario, in a 2-1 decision reported as Armstrong v Royal Victoria Hospital, 2019 ONCA 963, reversed. The majority concluded that the trial judge had improperly defined the standard of care by reference to the avoidance of the injury itself. That reasoning, the majority warned, would impose a standard of perfection, collapse breach into causation, and create de facto strict liability in technically demanding surgical work.
The Supreme Court of Canada restored the trial judgment, adopting the dissenting reasons of the Court of Appeal. The dissent’s reasoning is the doctrinal foundation of plaintiff-side intraoperative surgical practice in Ontario. It recognized that certain intraoperative obligations are so fundamental that a failure to achieve their intended protective effect may support an inference that they were not properly carried out. The standard is not defined by outcome, but the occurrence of a particular type of injury can inform whether the required steps were in fact adequately performed.
Three propositions follow from the dissent the Supreme Court adopted. Circumstantial inference is a legitimate path to proof of breach in surgical cases. Reliance on the mechanism of injury is not circular reasoning; it is part of the factual matrix that informs whether reasonable care was exercised. And the trial judge’s findings, where open on the evidence, are entitled to deference. Armstrong affirms that surgical negligence can be established through circumstantial reasoning where the nature and mechanism of injury support the inference that proper care was not taken.
Reframing recognized complications
A central piece of plaintiff-side surgical practice is the reframing of cases that defence experts have characterized as recognized complications. The “recognized complication” label is rhetorically powerful: if an injury is a known risk, the framing suggests inevitability rather than fault. But the label, on its own, is legally meaningless unless it is tied to the standard of care.
The wrong question is whether the injury is a recognized complication. The right question is whether the complication occurred despite the exercise of reasonable care. Once the mechanism of injury is examined, a “recognized complication” often begins to look less like an unavoidable risk and more like the consequence of an identifiable departure from the standard: improper instrument placement, failure to identify critical structures, excessive force or thermal spread, or inadequate intraoperative checks. The strategy is to deconstruct the complication and rebuild it as a sequence of events that reveal substandard care.
O’Neill-Renouf v Ibrahim: when circumstantial proof succeeds
The plaintiff in O’Neill-Renouf underwent a transvaginal tape (TVT) procedure and suffered an obturator nerve injury. The defence position was straightforward: the injury was caused by edema, a recognized complication of the procedure. The plaintiff’s theory was equally straightforward: the injury was the consequence of improper needle placement outside the intended surgical field.
The court found for the plaintiff. The case did not succeed on the fact of the injury alone. It succeeded because the court concluded that the most reasonable explanation for the injury was surgical negligence. Three factors carried that conclusion.
The first was the immediate onset of symptoms. The plaintiff experienced obturator nerve symptoms the moment she awoke from surgery. That timing strongly supported a direct traumatic mechanism rather than a delayed inflammatory process like edema. The second was anatomical specificity. The obturator nerve lies outside the intended surgical field for a TVT procedure. The defence’s recognized-complication theory had to explain why a nerve outside the field had been involved, and the explanation it offered did not fit. The third was the elimination of alternatives. On the totality of the clinical evidence, the edema explanation simply did not account for the picture as a whole. Once the alternatives had been examined and discounted, the negligent explanation was the one that remained.
O’Neill-Renouf is a worked example of the Armstrong dissent in operation. The case was built on the nature of the injury, the timing of symptoms, the anatomy, and the elimination of non-negligent alternatives. The operative report, which had suggested a benign procedure, was treated as one piece of evidence in a larger record rather than as the canonical account of what occurred.
Knight v Lawson: where the case falls short
Knight moved in the opposite direction. The plaintiff suffered a ureteric injury during a laparoscopically-assisted vaginal hysterectomy with right oophorectomy. The injury was not detected intraoperatively. The plaintiff did not allege that the ureteric injury itself was negligent; the theory was that the failure to identify and correct the injury before the conclusion of the operation fell below the standard of care, because a reasonably prudent gynecologist aware of the known risk of ureteric injury would have meaningfully assessed the ureters before closing.
The trial judge accepted the defence position on the intraoperative claim. The court found that the surgeon followed her usual practice of checking the ureters for peristalsis at the relevant stages of the operation, even though that step was not specifically documented in the operative note. The court also accepted expert evidence that certain types of ureteric injury, particularly those involving thermal or ischemic mechanisms, may not be visually apparent at the time they occur and may declare themselves clinically only days later. On that record, the trial judge refused to infer, from the failure to detect the injury, that the examination was inadequate. The injury could have occurred despite reasonable care.
The court did accept that the post-operative care fell below the standard of care: the surgeon failed to consider a ureteric injury when the post-operative clinical presentation warranted it. The claim still failed, however, on causation. The court found that the injury would likely have required the same surgical repair regardless of the timing of diagnosis, and that earlier diagnosis would not have materially altered the course. Knight is a reminder that standard-of-care breaches in surgical cases live or die on the coherence of the causation theory that follows.
Evidentiary challenges
Three evidentiary problems recur in intraoperative surgical work.
The first is expert reluctance. Surgical negligence cases depend entirely on the willingness of surgeons in the same specialty as the defendant to provide candid opinions. That willingness is often constrained. Reluctance shows up not as outright refusal but as opinions framed at a high level of generality, heavy reliance on the language of recognized complications, and a tendency to default to the proposition that adverse outcomes can occur in the absence of negligence. The response is to seek out experts who will engage with mechanism and probability rather than abstractions about risk, and who can articulate, on the specific anatomy, timing, and clinical course, why a particular injury is or is not consistent with the exercise of reasonable care.
The second is the limits of the operative record. Operative notes are summaries dictated after the fact. They reflect what was intended to occur or what ordinarily occurs, rather than a granular account of what actually happened. The defence routinely relies on the absence of any documented complication in the operative note as affirmative evidence that none occurred, but that inference is not always justified. The plaintiff’s task is to reconstruct the surgical event through the broader perioperative record: nursing records, anesthesia records, post-operative observations, imaging findings, and the timing and evolution of symptoms. Discrepancies between those sources and the operative note can be highly probative. The absence in the record of confirmatory steps that should have been documented, if performed, can itself form part of the case.
The third is the absence of direct evidence. There is rarely a witness to the precise moment of error, and almost never a contemporaneous record of the critical misstep. The case has to be built through circumstantial coherence: the nature and location of the injury, the timing of symptoms, the known mechanisms by which such injuries occur, and the elimination of plausible non-negligent causes. The plaintiff’s task is not to exclude every theoretical possibility but to demonstrate that the negligent explanation is more consistent with the totality of the evidence than any alternative.
Conclusion
Surgical negligence cases are among the most challenging in plaintiff-side medical malpractice practice. The law does not permit liability based on outcome alone, yet outcome is often the central piece of evidence. The art of the work lies in transforming outcomes into inferences and inferences into proof of negligence. Armstrong provides the framework. O’Neill-Renouf demonstrates how circumstantial evidence can establish negligence on the right record. Knight illustrates the limits, and the consequences of a causation theory that does not hold.
Three things make the difference. The mechanism of injury has to be clearly identified, anchored in the anatomy, timing, and clinical course. The defence’s recognized-complication framing has to be systematically dismantled, moved from possibility to implausibility on the specific facts of the case. And the inference of negligence has to emerge not as speculation but as the explanation that best fits the totality of the evidence. The cases that succeed do so because each piece of circumstantial evidence points in the same direction. The cases that fail are the ones where that coherence is missing, or where the causation theory cannot carry the breach finding through to a recoverable harm.
