In medical malpractice litigation, the plaintiff must prove two distinct things on a balance of probabilities: that the physician breached the standard of care, and that the breach actually caused the harm. The two are independent. A clear breach can fail at the causation stage.
I represented Christine Knight at trial in Knight v Lawson, 2023 ONSC 570. The trial judge found that the gynecologist who performed Ms. Knight’s hysterectomy breached the standard of care by failing to consider a ureteric injury when Ms. Knight returned to hospital with concerning symptoms after the surgery. We did not succeed on causation. The trial judge concluded that, on the medical evidence, earlier diagnosis would not have changed the outcome. The injury was likely ischemic in nature and had already progressed beyond the point where stenting or any other early intervention could have prevented the further surgery and complications that followed.
The case is worth setting out, both for what it shows about the law of causation in surgical malpractice and for what it shows about the limits of what a strong breach case can accomplish on its own.
The facts
In February 2014, Christine Knight underwent a laparoscopically-assisted vaginal hysterectomy and right oophorectomy at Stevenson Memorial Hospital in Alliston. The procedure was performed by Dr. Glasine Lawson, a gynecologist. According to the operative note, the surgery went well, and Ms. Knight was discharged the next day.
What was not appreciated at the time was that the surgery had damaged Ms. Knight’s right ureter, one of the two tubes that drain urine from the kidneys to the bladder.
A few days after surgery Ms. Knight began feeling unwell. On the fifth day she returned to hospital. By the next day she was back under Dr. Lawson’s care. Dr. Lawson identified the problem as either an abscess compressing the ureter or a kidney infection, and started antibiotics directed at both possibilities. She did not consider the alternative possibility that the ureter itself had been injured during the surgery, and she did not consult a urologist.
Five days later Ms. Knight was feeling better and was discharged. Eight days after that, she returned to hospital again, this time with a large collection of fluid in her abdomen and uncontrolled urinary leakage from her vagina. A new CT scan showed that her right ureter was leaking and that urine was tracking through sutures from the surgery into the vagina, a condition known as a ureterovaginal fistula. She was transferred to a different hospital and placed under the care of a urologist.
The trial findings
The trial judge’s findings broke into three distinct conclusions.
No breach in the surgery itself. The court accepted Dr. Lawson’s evidence that she would have inspected the ureters during the procedure, even though that inspection was not documented in the operative note. The trial judge also found that, at the time of surgery, the ureter would not have shown a visible injury even if inspected. The operative care therefore met the standard.
Breach in the post-operative management. When Ms. Knight returned to hospital five days after surgery, the differential diagnosis Dr. Lawson considered (abscess or kidney infection) did not include ureteric injury. The trial judge found that this was a breach of the standard of care. A reasonable gynecologist, faced with a patient returning unwell after a recent hysterectomy and showing the constellation of symptoms Ms. Knight had, should have considered ureteric injury as a possibility and should have obtained a urology consultation. Had that consultation occurred, the trial judge found, a urologist likely would have attempted to repair the injury with ureteric stenting.
No causation. Despite that breach, the claim failed at causation. The medical evidence at trial established that the ureteric injury was likely ischemic in nature, caused by surgical cautery during the hysterectomy, rather than a mechanical injury such as a partial transection. An ischemic ureteric injury follows a different clinical course from a mechanical one. The damaged tissue continues to break down after the inciting event. By the time Ms. Knight returned at the five-day mark, the trial judge found, the injury had progressed to the point where ureteric stenting would not have prevented the eventual fistula or the surgical reconstruction that followed. As the trial judge put it, “Earlier stenting would not likely have led to Ms. Knight avoiding the need for further surgery, nor would it have accelerated the timeline when she could have had the surgery.”
The action was dismissed.
What this case shows
A few things, looking back.
Breach and causation are separate elements, and the second one can be the harder of the two. This is something I tell prospective clients in the first conversation, but Knight is a useful reminder of how decisive it can be. Even when the breach analysis is straightforward (a doctor faced with a patient who returned unwell five days after a hysterectomy should have included ureteric injury on the differential), causation can dismantle the case if the harm would have happened anyway given the underlying mechanism of injury.
Mechanism of injury matters. In ureteric injury cases specifically, and in any case where the harm involves a progressive process (ischemic damage, infection, hypoxic injury), the mechanism analysis is doing real work. A mechanical injury, like a transection or a clamp injury, can often be repaired if caught early. An ischemic injury, where tissue has been devascularized and is going to break down regardless of when it is recognized, is a different problem. Earlier diagnosis of an ischemic ureteric injury at five days does not necessarily change the trajectory.
Cases like this need to be analyzed for causation at the front end, not the back end. In any claim involving a surgical injury that was missed on follow-up, the question to ask first is whether the injury, by its nature, would have responded to earlier intervention. If the answer turns on the mechanism (mechanical versus ischemic, transmural versus partial, contained versus expanding), the medical evidence on that point will likely decide the case. That evidence should be sought and tested early.
Most surgical malpractice cases turn on facts of this kind. Surgical injuries to ureters, bowel, blood vessels, and nerves are recognized risks of major surgery. They are not, by themselves, evidence of negligence. Where there is a basis to allege negligence, it is usually in the recognition and management after the surgery rather than in the surgery itself. Knight is consistent with that pattern: the surgical care was found to meet the standard, and the breach finding was on the post-operative recognition. The causation question, however, is what determined the outcome.
For more on surgical injury claims, see the Surgical Errors practice page. For an overview of the legal process and the role of causation in particular, see Suing for Medical Malpractice in Ontario: What You Need to Know.
The first conversation is free and strictly confidential. The earlier we look at the records, the better.
Decision Date: January 27, 2023
Jurisdiction: Ontario Superior Court of Justice
Citation: Knight v Lawson, 2023 ONSC 570 (CanLII)
