Sacks v. Ross: Addressing Causation in Cases of Systemic Delay Caused by Multiple Defendants

In the recent case of Sacks v. Ross, the Ontario Court of Appeal had the opportunity to consider and clarify the law of causation in medical malpractice cases that involve the negligence of multiple defendants.   The Court also set out a new format for jury questions in these cases.  The directions and questions from the Court of Appeal provided welcome clarification and will help jurors to better understand how to fairly decide causation issues in these cases.

The Facts

Jordan Sacks went into Sunnybrook Hospital for a routine bowel surgery. After the surgery, the sutures holding the ends of the bowel came apart, causing an anastomotic leak. The contents of Mr. Sacks’ bowel spilled into his abdominal cavity. Anastomotic leaks must be treated quickly to prevent infection and sepsis. Unfortunately for Mr. Sacks, his healthcare team did not discover the leak until much later. By the time his doctors discovered the leak and began treatment, Mr. Sacks’ body had gone into septic shock. The infection was so severe that he had to have both of his legs amputated below the knees and have all of his fingertips amputated.  He was in a medically induced coma for 3 months, in hospital for 7 months, and at a rehabilitation centre for a further 4 months.

Mr. Sacks’ lawyers argued that the delay in diagnosis and treatment of the anastomotic leak caused Mr. Sacks to suffer septic shock and the amputations, and that the delay was the result of multiple errors made by a team of doctors, nurses, and other health professionals at Sunnybrook Hospital.

After a lengthy trial, the jury returned a verdict that found that five defendants have breached their respective standards of care.  However, the jury did not conclude that the breaches of the standard of care caused the injuries.  The case was dismissed.

Issues on Appeal

Mr. Sacks appealed on the basis that the jury was not properly instructed on how to approach the issue of causation and that the members of the jury were not asked the correct questions.  Because of these failures, the jury’s answers were ambiguous and could not form the basis for a supportable judgment.

The Court of Appeal was asked to consider the following three issues:

  1. Did the trial proceed on a correct understanding of causation?
  2. Were the jury questions on causation appropriate?
  3. Were the jury instructions on causation legally correct?
  4. Did a legal error in the jury questions or in the jury instructions deprive the plaintiffs of a fair trial?

The Decision

Correct Reasoning on Causation in Negligence Cases

The Court set out the following general reasoning process for causation:

  1. What likely happened?
  2. What likely would have happened if the defendant hadn’t breached the standard of care?
  3. What is the allocation of fault among defendants?

If this process leads to the conclusion that the plaintiff wouldn’t have suffered the injury if the defendant hadn’t been negligence, the “but for” causation test is satisfied.

The Court noted that cases arising from allegations of delayed diagnoses involving multiple defendants raise more complex causation issues. The “but for” test of causation continues to apply in these cases. Each of the defendants’ negligence must be a necessary cause of the injury. However, that defendant’s negligence need only be a cause of some injury to the plaintiff, not the entirety of the injury.

The Appropriate Jury Questions in Complex Delayed Diagnosis Cases

Before articulating the appropriate jury questions in a complex delayed diagnosis case involving multiple defendants, the Court set out the following characteristics that are required in jury questions:

  • The questions should be tailored to the specific findings of fact necessary to decide the case.
  • The questions should respond to the facts in issue and be logically sequential.
  • Questions should be expressed as simply and clearly as possible.
  • No question should be a compound question or contain an embedded assumption.
  • Questions should be neutrally expressed and should not nudge the jury toward a particular result.
  • If possible, the questions should be answered in a “yes” or “no” format, followed by a blank space in which the jury can insert a damages figure if it finds liability.
  • In professional negligence cases, the jury should be asked to provide reasons for any finding of negligence.
  • The jury’s answers should permit the trial judge to complete the judgement.

In terms of process, trial counsel should propose the jury questions to the trial judge in advance. The trial judge should carefully scrutinize the draft jury questions and has an obligation to reject formulations that do not reflect the required characteristics of jury questions, even if counsel have agreed on those questions. All of this should be done well before jury instructions are prepared.

The Court of Appeal framed the appropriate jury questions as follows:

  • Have the Plaintiffs proven, on a balance of probabilities, that a delay in treatment caused Jordan Sacks’s injuries?

If the answer to that question is “yes”, in respect of each individual defendant:

  • Have the Plaintiffs proven, on a balance of probabilities, that the delay resulting from [this defendant’s] breach of the standard of care caused or contributed to the injuries of Jordan Sacks?

If the answer to that question is “yes”, in respect of each individual defendant:

  • How did [this defendant] breach the standard of care? Please provide clear and specific answers.

The new jury questions include two important changes from the questions originally ordered by the trial judge.  First, the jury must begin by answering whether a delay in treatment, whether caused by one defendant or multiple defendants in combination, caused injuries to the plaintiff.  Second, when dealing with each defendant’s role in the delay, the words “or contributed to” are included in the question.  This is an important reminder to members of the jury that no one defendant’s conduct must be the cause of the plaintiff’s injury, as long as the negligence contributed to the delay that caused the injury.

Jury Instructions

The Court of Appeal identified the following best practices for the formulation and circulation of jury instructions:

  1. The trial judge should provide a draft set of jury instructions to the parties ahead of time and give counsel an opportunity to make submissions.
  2. The trial judge should give the members of the jury a written copy of the jury instructions together with the jury questions.

The Court noted that the purpose of jury instructions is to explain to the jury what their role is in trial and their corresponding duties.  This is accomplished by incorporating the following principles and content:

  • Instructions should explain legal principles that jurors are to apply to reach their decision.
  • Instructions should be legally accurate and expressed in plain language, avoiding “legalese”.
  • Instructions should strike the crucial balance of being both comprehensive and comprehensible.
  • The trial judge must isolate the critical issues in the case and tailor the charge to them.
  • Instructions should avoid overreliance on model charge manuals or long quotes from appellate decisions. Slavishly quoting the exact words of a legal test or specimen instruction might in fact constitute an error if it operates to confuse the jury.

In a delayed diagnosis case with multiple tortfeasors, the jury instructions must carefully instruct members of the jury on the reasoning process to be employed in moving through the events to determine causation. Generally speaking, a negligent tortfeasor should not be able to sidestep liability on the basis that there was sufficient cumulative delay resulting from negligent acts or omissions of other defendants, so that it cannot be proven that the defendant’s particular contribution was “necessary” to cause the injury. Causation will be established if the plaintiff proves on a balance of probabilities that the negligence of the defendant caused or contributed to the delay and that the delay caused the injury.


Ultimately, Court of Appeal found that the deficiencies in the trial judge’s jury instructions and in the formulation of the jury questions would not have changed the jury’s verdict in the case.  It dismissed the plaintiffs’ appeal.


The Court of Appeal provided much-needed clarity on the application of causation principles to delay diagnosis cases involving multiple doctors and healthcare practitioners. Clarification of these principles has also led to the formulation of a defined set of jury questions that will help members of future juries to work through causation problems in a way that is fair to plaintiffs and which prevents negligent defendants from sidestepping their liability by suggesting that their particular contribution to the delay was not significant enough to have changed the outcome. This will avoid the very problem the plaintiffs complained of in Sacks – that multiple defendants may fall below the standard of care and create a global delay that causes catastrophic injury to a plaintiff, but each of them can avoid liability by suggesting that the negligence of others resulted in the delay that caused the injury, ultimately leaving the plaintiff without recourse. Unfortunately for Mr. Sacks, he did not have the benefit of a jury being able to work through questions framed in that way.

Patrick Brown


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