The Canadian common law of informed consent is grounded in patient autonomy: the patient, not the doctor, decides whether to proceed with a particular treatment. The physician’s obligation is to provide the information necessary to make a meaningful choice. The framework, articulated in Reibl v Hughes, [1980] 2 SCR 880, and Hopp v Lepp, [1980] 2 SCR 192, requires disclosure of material risks, alternatives, and the consequences of not proceeding. The standard is patient-centred: what would a reasonable patient in the plaintiff’s circumstances want to know to make an informed decision?
The framework works reasonably well for the single-procedure case — a hernia repair, a hysterectomy, a colonoscopy. It becomes more complicated where the treatment is multi-step. A plan involving three embolizations followed by surgical resection of a brain arteriovenous malformation is not one procedure; it is a coordinated sequence of procedures, each with its own risks, executed over months by a treatment team of multiple specialists. What does informed consent look like in that context? Whose obligation is it to obtain? And against what risk picture should the patient’s decision be measured?
Denman v Radovanovic, 2024 ONCA 276, is the Court of Appeal for Ontario’s recent and authoritative answer. The court affirmed a trial finding of liability against three physicians at Toronto Western Hospital for failure to obtain informed consent in a multi-step AVM treatment plan that left a 54-year-old man with catastrophic brain injury during the third embolization. Damages had been settled pretrial at $8.5 million. The trial had proceeded on liability only. The appellate affirmance establishes several doctrinal propositions of substantial importance: that the disclosure standard for multi-step treatment requires disclosure of cumulative risks across the entire plan; that the obligation to obtain consent rests collectively on the team, not solely on the physician performing each procedure; that the disclosure must include the risks of not proceeding alongside the risks of treatment; and that directing the patient to misleading information aids does not satisfy the disclosure obligation.
The case is doctrinally one of the most important Ontario informed consent decisions in recent years. It is also a meaningful plaintiff appellate win that adds important balance to the rewritten cluster on this site.
The clinical context: AVMs and embolization
A brain arteriovenous malformation (AVM) is an abnormal tangle of blood vessels where arteries connect directly to veins without the normal capillary bed between them. The direct shunt produces high-pressure arterial blood flowing into vessels not designed to handle it. Over time, the abnormal flow can produce:
- Hemorrhage (rupture of the AVM with intracerebral bleeding — the most catastrophic risk)
- Seizures
- Progressive neurological deficits from mass effect or vascular steal phenomena
- Headaches
The natural history of an asymptomatic AVM is variable. The annual risk of hemorrhage is typically estimated in the range of 2 to 4 percent per year, with substantial individual variation depending on the AVM’s anatomic characteristics, the patient’s age, and other clinical factors. Some AVMs remain stable for decades; others rupture catastrophically without warning. The cumulative lifetime risk for a younger patient with an unruptured AVM is meaningful, but it must be weighed against the cumulative risk of intervention.
Treatment options for AVMs include:
- Conservative management: observation with periodic imaging follow-up
- Microsurgical resection: open neurosurgical removal of the malformation
- Stereotactic radiosurgery: focused radiation that occludes the AVM over months to years
- Endovascular embolization: catheter-based delivery of embolic material (coils, glue, particles) to occlude the abnormal vessels
Each treatment carries its own risk profile. Surgery carries the risks of general anesthesia and any neurosurgical procedure (bleeding, infection, neurological deficit). Radiosurgery has a delayed effect and carries radiation-related risks. Embolization carries the risks of catheter manipulation (vessel rupture, embolic material migration to normal brain tissue, stroke, hemorrhage from flow changes).
Multi-step treatment plans are common in complex AVM management. The plan typically involves staged embolizations to reduce the AVM’s size and flow, followed by definitive surgical or radiosurgical treatment. The staged approach reduces some intra-procedural risks but introduces its own complications: each procedure adds incremental risk, the cumulative procedural risk aggregates, and the AVM’s flow dynamics may change between stages in ways that increase rather than decrease the risk of subsequent intervention.
This is the clinical context for the disclosure question in Denman. Mr. Denman had an AVM with a real but quantifiable natural risk. He was offered a multi-step treatment plan with its own substantial procedural risks. The question for informed consent was whether the disclosure framework adequately equipped him to choose between the proposed treatment and conservative management.
The substantive facts
Mr. Denman was 54 years old when his AVM was discovered. He had not suffered a hemorrhage. The AVM was asymptomatic at the time of discovery — identified during evaluation for unrelated symptoms.
Between 2014 and 2015, the AVM team at Toronto Western Hospital formulated a treatment plan. The plan involved a series of embolizations followed by possible surgical resection. Three physicians played principal roles:
- Dr. ter Brugge — a senior interventional neuroradiologist involved in the AVM conference where the treatment plan was developed and in consultations with Mr. Denman about the plan
- Dr. Radovanovic — a neurosurgeon who participated in the treatment plan development and consultations
- Dr. Pereira — an interventional neuroradiologist who performed the third embolization
The disclosure process is the doctrinal centerpiece of the case. Mr. Denman’s informed consent was sought for the proposed multi-step plan. The trial judge found that the disclosure was inadequate. The disclosure did not address the cumulative risks across all the planned procedures; it did not adequately address the alternative of no treatment; and it was supplemented by direction to a website that contained misleading information about AVMs and their treatment.
Mr. Denman proceeded with the plan. The first embolization took place. The second took place. In June 2015, the third embolization produced a catastrophic intracerebral injury. Mr. Denman was left with left-sided paralysis.
Damages were settled pretrial at $8.5 million. The trial proceeded on liability only.
The trial finding of breach
The trial judge found that all three physicians had breached the standard of care for obtaining informed consent. The breaches included:
- Failure to disclose cumulative risks across the multi-step plan. The patient was not adequately informed about the aggregate risk profile of three embolizations followed by surgical resection. Disclosure for each procedure separately, even if individually adequate, would not satisfy the standard for a coordinated plan.
- Failure to disclose the risks of not proceeding. The patient was not adequately informed about the natural history of his AVM if untreated. Without that comparative information, he could not meaningfully choose between treatment and observation.
- Direction to misleading information. Dr. ter Brugge directed Mr. Denman to a website that contained inaccurate or misleading information about AVMs and their treatment. Referring a patient to inaccurate information aids does not satisfy disclosure and, in this case, contributed to the inadequacy.
The trial judge applied the Reibl v Hughes modified objective causation test. The question was whether a reasonable patient in Mr. Denman’s circumstances would have refused the treatment if properly informed. The trial judge found yes: neither Mr. Denman nor a reasonable patient in his position would have elected to proceed with the multi-step plan if adequately informed about the cumulative risks and the alternative of conservative management. Dr. Findlay, an expert witness at trial, testified that he personally would not have offered the proposed intervention to a patient in Mr. Denman’s circumstances because it was too high-risk.
The trial judge found all three physicians liable. Damages had been settled at $8.5 million.
The appellate analysis
The appellants raised several grounds challenging the trial judge’s findings:
- That the disclosure standard for multi-step treatment did not require disclosure of cumulative risks; rather, separate disclosure for each procedure was sufficient
- That only the physician actually performing the third embolization could be liable for failure to obtain informed consent for that procedure
- That the trial judge had erred in finding that a reasonable patient would have refused the treatment
The Court of Appeal dismissed the appeal on all grounds.
The cumulative risks doctrine
The Court of Appeal’s articulation of the cumulative risks doctrine is the heart of the case. The court held that where the treatment plan involves multiple procedures over time, the patient must be informed of the cumulative risks across all the planned procedures. The disclosure obligation operates at the level of the plan, not at the level of each individual procedure considered in isolation.
The reasoning is doctrinally grounded in patient autonomy. A patient consenting to a multi-step plan is consenting to the entire planned course of treatment, not just the first procedure. To make a meaningful informed choice, the patient must understand the risk profile of the entire course — not just the slice they are currently being asked to authorize. Disclosure that addresses only the next procedure denies the patient the information needed to choose between proceeding with the plan and choosing a different course (different treatment, no treatment, or stopping at an earlier stage).
The doctrine has significant practical implications for multi-step treatment in any specialty. Examples beyond AVM management include:
- Staged cardiac valve replacement procedures
- Multi-stage cancer treatment protocols (surgery + chemotherapy + radiation)
- Multi-stage orthopaedic reconstructions
- IVF cycle treatment plans
- Phased plastic surgery procedures
- Multi-stage dental implant procedures
In each context, the cumulative risks doctrine requires that the disclosure address the aggregate risk profile of the entire planned course, not just the procedures the patient is being asked to authorize in the current consent conversation.
For practising physicians, the doctrinal implication is significant. Consent for multi-step plans should be obtained against the backdrop of an explicit cumulative-risk discussion. The disclosure conversation should explicitly address what the patient is being asked to authorize across the entire plan, not just the next step. Documentation of the conversation should reflect this scope.
The collective team responsibility doctrine
The second major doctrinal contribution is the holding that informed consent for a team-developed multi-step plan is the collective responsibility of the team, not the sole responsibility of the physician performing each procedure.
The appellants had argued that only the physician actually performing each procedure could be held liable for failure to obtain informed consent for that procedure. On that view, Dr. ter Brugge (who never performed an embolization himself) could not be liable; only Dr. Pereira (who performed the third embolization) could be liable for the disclosure for that procedure.
The Court of Appeal rejected this approach. The court cited two key authorities:
Ferguson v Hamilton Civic Hospitals, 1983 CanLII 3059 (ONSC). The Ontario Superior Court of Justice (then the Ontario High Court) had held that a neurosurgeon who did not perform a procedure could nonetheless be liable for inadequate disclosure where he had been aware of the limitations of the performing physician. Ferguson establishes that the disclosure duty is not strictly co-extensive with the act of performing the procedure. Physicians who participate in formulating treatment plans, who consult with patients about those plans, or who otherwise hold themselves out as involved in the patient’s care can bear disclosure obligations even where they do not perform the procedure.
Section 13 of the Health Care Consent Act, 1996. The Ontario statute expressly contemplates that “one health practitioner may, on behalf of all the health practitioners involved in the treatment plan, propose the treatment plan and, in doing so, may determine the patient’s capacity to give or refuse consent to the treatments referred to in the plan and obtain a consent or refusal of consent.” The provision recognizes that modern medical practice involves team-based care for complex conditions, and provides the statutory framework for treatment-plan-level consent.
The combination produces a clean doctrinal framework. Where a treatment plan is developed by a team and proposed to the patient, the consent for the plan operates at the team level. Physicians involved in formulating or proposing the plan bear disclosure responsibility for the plan. The fact that a particular physician did not personally wield the catheter on a particular day does not insulate that physician from disclosure liability for inadequate consent to the plan.
The doctrinal implication is significant for modern hospital practice. AVM teams, tumour boards, transplant teams, surgical-medical-oncology multidisciplinary teams, and other team-based care models all operate within this framework. The disclosure obligation does not pass from team member to team member with each procedure; it is held collectively at the team level. Each team member who participates in the plan formulation or in consultations with the patient about the plan bears responsibility for ensuring the disclosure is adequate.
The “no treatment” comparison requirement
A third doctrinal point is the holding that disclosure must address the risks of not proceeding alongside the risks of the proposed treatment. Without comparative information, the patient cannot make a meaningful choice.
In Denman, Dr. ter Brugge failed to disclose the lifelong risk profile of the AVM if left untreated. The trial judge found this to be a separate component of the disclosure failure. The Court of Appeal affirmed.
The doctrinal point: informed consent is fundamentally a comparative decision. The patient is choosing between treatment and an alternative (which may be a different treatment, no treatment, or a deferred decision). For the choice to be meaningful, the patient must understand the risk profile of both options. Disclosure that addresses only the proposed treatment, without addressing what would happen if the patient did not proceed, deprives the patient of the comparison required for the choice.
For practising physicians, the implication is that consent discussions should explicitly address the alternative-of-no-treatment as part of the disclosure. The discussion need not be lengthy where the alternative is clearly inferior — for emergent treatment of a life-threatening condition, the comparison may be straightforward. But for elective treatment of conditions with significant uncertainty about natural history (like asymptomatic AVMs, certain cancers, certain cardiac conditions), the no-treatment comparison is essential.
The misleading website issue
A fourth doctrinal point is the finding that Dr. ter Brugge had directed Mr. Denman to a website with misleading information about AVMs and their treatment. The trial judge treated this as part of the inadequate disclosure. The Court of Appeal affirmed.
The doctrinal implication is that supplementary patient education materials are part of the disclosure framework. Where a physician directs a patient to additional information sources, the physician bears some responsibility for the accuracy and balance of those sources. Directing a patient to a website that contains misleading information is not a substitute for adequate disclosure; in some circumstances, it can actively contribute to the disclosure failure.
For practising physicians, the operational lesson is that patient education referrals should be made with care. Authoritative, peer-reviewed, and balanced sources are preferable. Vendor websites, advocacy organizations with particular agendas, and other potentially partisan sources should be avoided or, if referenced, accompanied by appropriate framing.
The Reibl v Hughes modified objective causation test
The fifth doctrinal point is the affirmation of the trial judge’s causation analysis under the Reibl v Hughes modified objective test.
The test asks: would a reasonable patient in the plaintiff’s circumstances have refused the treatment if properly informed? The test is “modified objective” because:
- The reasonable patient standard is objective (not what this particular patient would have done, but what a reasonable patient would have done)
- “In the plaintiff’s circumstances” injects subjective elements (age, family situation, occupation, personal values, particular health concerns relevant to the decision)
The combination produces a test that asks: what would a reasonable patient with this plaintiff’s particular circumstances have decided if properly informed?
In Denman, the trial judge found that neither Mr. Denman personally nor a reasonable patient in his circumstances would have elected to proceed with the multi-step plan if properly informed. The Court of Appeal affirmed. The reasoning rested on:
- The substantial cumulative risk profile of the multi-step plan
- The asymptomatic nature of the AVM at the time of treatment
- The availability of conservative management as a credible alternative
- Dr. Findlay’s testimony that he personally would not have offered the procedure to a patient in Mr. Denman’s circumstances
The causation finding is doctrinally important because it shows the test operating to support liability where the disclosure failure is substantial and the proposed treatment is elective. The framework is most demanding for plaintiffs where the disclosure failure was minor and the treatment was necessary; it is most favourable for plaintiffs where the disclosure failure was substantial and the treatment was elective and high-risk.
The doctrinal lessons
The case stands for several propositions.
Informed consent for multi-step treatment requires cumulative risk disclosure. Disclosure must address the aggregate risk profile of the entire planned course of treatment, not just the next individual procedure. The patient is consenting to the plan; the disclosure must operate at the plan level.
The disclosure obligation is collective for team-developed plans. Physicians involved in formulating treatment plans or in consultations with patients about those plans bear disclosure responsibility for the plan. The obligation does not rest solely on the physician performing each procedure on the day of the procedure.
Section 13 of the Health Care Consent Act, 1996 provides statutory support. The provision expressly contemplates one practitioner proposing a treatment plan on behalf of the team, providing the legislative framework for treatment-plan-level consent in Ontario.
Disclosure must address the risks of not proceeding. Informed consent is fundamentally a comparative decision. The patient must understand the risk profile of both treatment and no-treatment to make a meaningful choice.
Patient education materials are part of the disclosure framework. Direction to misleading information aids does not satisfy disclosure and can actively contribute to the disclosure failure. Physicians should refer patients only to balanced, accurate sources.
The Reibl v Hughes modified objective causation test can support plaintiff outcomes. Where the disclosure failure is substantial and the treatment is elective and high-risk, the test will often find that a reasonable patient in the plaintiff’s circumstances would have refused. The framework is not stacked against plaintiffs; it operates on the merits of the disclosure and the realistic alternatives.
The informed consent cluster
Denman v Radovanovic operates as the principal Ontario substantive anchor for the informed consent sub-cluster in the rewritten case-comment library on this site. The cluster now spans:
- Denman v Radovanovic (Ontario, appellate, this case): multi-step treatment, cumulative risks, team responsibility, no-treatment comparison
- Denman v Radovanovic costs decision (Ontario, costs): the costs jurisprudence flowing from the same litigation
- Gilmore v Love (BC): real-time informed consent during labour
- Khaleel v Indar (Alberta): disclosure of alternatives + modified objective test
- Thorburn v Grimshaw (Nova Scotia): summary judgment dismissing informed consent claim
- A.G. v Rivera (BC): patient refusal doctrine (distinct from informed consent)
- Kotorashvili v Lee (Ontario): mid-treatment plan changes requiring renewed consent
The cluster now provides comprehensive coverage of the major informed consent doctrinal areas. Denman is the principal anchor for multi-step treatment disclosure, team responsibility, and the no-treatment comparison requirement.
The appellate cases cluster — eight cases, two plaintiff affirmances
Denman v Radovanovic is the eighth case in the rewritten appellate cluster and the second appellate affirmance of a plaintiff trial victory:
- Willick v Willard (Ont CA): affirmance of defendant judgment
- Hanson-Tasker v Ewart (BC CA): affirmance of defendant judgment
- Dumesnil v Jacob (Manitoba CA): new trial after defendant judgment
- Penate v Martoglio (Ont CA): new trial after defendant judgment
- Rybakov v Khattak (BC CA): affirmance of defendant judgment
- Focken v Miller (BC CA): affirmance of defendant judgment
- Henry v Zaitlen (Ont CA): affirmance of plaintiff jury verdict
- Denman v Radovanovic (Ont CA): affirmance of plaintiff bench-trial liability finding
The cluster now spans the full spectrum of appellate outcomes — defendant-favourable affirmances, intervention on substantive error, intervention on procedural defects, and now two clear plaintiff affirmances. The previously defence-heavy appellate jurisprudence in the library is now substantially balanced.
The plaintiff wins sub-grouping — three cases
Denman v Radovanovic is the third plaintiff win in the rewritten cluster:
- Kotorashvili v Lee (Ontario, trial): $35,000 for premature hardware removal — deviation from own treatment plan + informed consent for mid-treatment changes
- Henry v Zaitlen (Ontario, trial + appellate): $1.5 million jury verdict — failure to investigate progressive neurological symptoms
- Denman v Radovanovic (Ontario, trial + appellate): $8.5 million pretrial settlement on damages — failure to obtain informed consent for multi-step AVM treatment plan
The three cases illustrate substantially different fact patterns and damages calibrations:
- Kotorashvili: bench trial; modest damages reflecting limited long-term impact
- Henry: jury trial; $1.5 million reflecting catastrophic spinal cord injury with partial recovery
- Denman: bench trial on liability only; $8.5 million pretrial settlement reflecting catastrophic brain injury with permanent paralysis
The sub-grouping provides substantive balance to the cluster’s many causation/SOC defeat cases and illustrates the range of plaintiff outcomes available when the facts and the doctrinal framework align.
Why this case matters
For prospective clients considering multi-step treatment. Informed consent for complex multi-step treatment requires more than disclosure for each procedure separately. The cumulative risks of the entire planned course matter. The alternative of not proceeding matters. The information aids you are referred to matter. If you are facing a multi-step elective treatment for a condition that has a credible alternative of conservative management, you are entitled to a comprehensive disclosure that lets you compare the options fairly. For more on the realistic evaluation of malpractice claims, see Suing for Medical Malpractice in Ontario: What You Need to Know.
For plaintiff counsel. The case provides important doctrinal tools for informed consent litigation:
- Cumulative risks framework for multi-step treatment
- Team responsibility framework for plans developed by multidisciplinary teams
- The no-treatment comparison requirement
- The misleading materials doctrine
- The modified objective causation test operating to support plaintiff outcomes
For multi-step treatment cases involving complex specialties (interventional neuroradiology, vascular surgery, multi-stage oncology, complex orthopaedics, IVF), Denman is essential precedent.
For defence counsel. The case clarifies the scope of the disclosure obligation in modern team-based hospital practice. Defence to informed consent claims will need to address not just whether the performing physician obtained adequate consent, but whether the team as a whole did. Where the disclosure was inadequate at the plan level, individual team members participating in the plan may not be insulated by the fact that they did not personally perform each procedure.
For practising physicians, particularly those in team-based specialties. The operational lessons:
- Disclosure for multi-step plans should address cumulative risks, not just procedure-specific risks
- Document the discussion of cumulative risks in the chart
- Include explicit discussion of the no-treatment alternative
- Refer patients only to balanced, authoritative patient education materials
- Recognize that team-based care creates collective consent obligations — participation in plan formulation creates disclosure responsibility
- Section 13 of the Health Care Consent Act, 1996 permits team-based consent through one practitioner; that practitioner’s disclosure must be adequate to the entire plan
For more on the informed consent framework generally, see the cases linked in the informed consent cluster section above. For more on the related costs jurisprudence flowing from this litigation, see Denman v Radovanovic costs decision.
Decision Date: April 16, 2024
Jurisdiction: Court of Appeal for Ontario
Citation: Denman v Radovanovic, 2024 ONCA 276 (CanLII)
Outcome: Plaintiff trial finding of liability against three physicians affirmed. Damages settled pretrial at $8.5 million.
Key authorities: Reibl v Hughes, [1980] 2 SCR 880 (informed consent framework); Hopp v Lepp, [1980] 2 SCR 192 (companion case); Van Dyke v Grey Bruce Regional Health Centre, 2005 CanLII 18841 (ONCA) (patient decision-making authority); Ferguson v Hamilton Civic Hospitals, 1983 CanLII 3059 (ONSC) (non-performing physician liability); Health Care Consent Act, 1996, SO 1996, c 2, Sched A, s 13 (team treatment plan consent framework)
