Henry v Zaitlen: A Jury Verdict for Delayed Diagnosis of a Spinal Cord Fistula

Most of the appellate decisions in the rewritten case-comment cluster on this site involve plaintiffs appealing from defendant trial judgments. The defendants prevailed at trial; the plaintiff sought appellate review; the Court of Appeal in most cases affirmed. Henry v Zaitlen, 2024 ONCA 243, is the opposite posture. A young man with progressive neurological symptoms developed paraplegia from an undiagnosed spinal dural arteriovenous fistula that his treating neurologist failed to investigate. A jury awarded just under $1.5 million in damages. The neurologist appealed. The Court of Appeal for Ontario dismissed the appeal.

The case is doctrinally significant for several reasons. It is one of the few clean appellate affirmances of a plaintiff jury verdict in modern Ontario medical malpractice practice. It engages a distinctive standard-of-care theory — the “failure to investigate” framework — that operates differently from the more familiar misdiagnosis or wrong-treatment claims. It articulates the appellate review framework for plaintiff jury verdicts (substantial deference to the jury’s findings). And it shows how the Wilson v Swanson “error of judgment” defence fails when the alleged error consists of sustained inaction in the face of mounting evidence requiring response.

The clinical condition: spinal dural arteriovenous fistula

A spinal dural arteriovenous fistula (SDAVF) is an abnormal direct connection between an artery and a vein at the dural sheath of a spinal nerve root. The shunt bypasses the normal capillary system and produces venous hypertension in the spinal cord. The elevated venous pressure compromises drainage from the cord itself, producing congestive ischaemic damage to the cord tissue.

The clinical presentation is typically a progressive myelopathy: lower extremity weakness, sensory disturbance, gait impairment, and bladder and bowel dysfunction. Symptoms develop over weeks to months and worsen if untreated. The natural history is progressive deterioration to paraplegia.

SDAVF is treatable. The fistula can be closed surgically or by endovascular intervention. With timely diagnosis and treatment, the prognosis can be very good — patients can recover substantial function. The time window matters: earlier diagnosis preserves more cord tissue and produces better outcomes. Late diagnosis, after extensive cord damage has occurred, produces worse outcomes even with successful fistula closure.

SDAVF is rare. It is uncommon at any age and particularly uncommon in younger adults. Presentation in the third or fourth decade does occur. The rarity contributes to the diagnostic challenge — the condition is not at the top of the differential for a young patient with neurological symptoms — but rarity does not excuse failure to consider it when the clinical picture supports it.

The diagnostic test is magnetic resonance imaging. Standard MRI of the relevant spinal level will typically show characteristic findings (cord edema, intramedullary signal change, prominent perimedullary veins). Definitive confirmation requires spinal angiography. The key point: a focused MRI of the relevant spinal level is the first step. Where lumbar imaging is unrevealing and symptoms are progressing, thoracic imaging is the natural next step.

The substantive facts

Mr. Henry, a man in his thirties, presented to the emergency department of Brampton Civic Hospital on January 27, 2010 with complaints of lower back pain, numbness down the left leg and pelvic area, and difficulty urinating and voiding. MRI of his lumbar spine showed enhancement of the conus medullaris (the terminal end of the spinal cord) and of the cauda equina nerve roots below the conus. An internal medicine specialist examined him on January 28 and referred him to Dr. Zaitlen, a neurologist, on an urgency basis.

January 29, 2010 — first neurology consultation. Dr. Zaitlen described the case as an emergency referral for new-onset sensory loss over the perineum, bowel and bladder dysfunction, and sensory and motor loss in the lower limbs. He noted no exposure, injury, or infection that could be identified as a trigger. He documented a differential diagnosis of trauma, infection, inflammation, and cancer, and ordered a lumbar puncture to obtain cerebrospinal fluid for analysis.

February 12, 2010 — second consultation. Mr. Henry reported continued pain. His symptoms had not resolved but were, in Dr. Zaitlen’s assessment, “at least stable.” CSF testing had ruled out cancer and reduced the likelihood of infection. There was little evidence of trauma. Mr. Henry had a high white cell count but did not have meningitis. Some test results were still pending. Dr. Zaitlen did not order further tests; he elected to continue clinical follow-up.

March 5, 2010 — third consultation. Mr. Henry continued to have numbness in the saddle area, muscle twitching and spasms, stiffness in the lower back, hip and buttock pain, and sensory discomfort in the leg. Symptoms were neither worsening nor improving, in Dr. Zaitlen’s view. The condition remained undiagnosed — what Dr. Zaitlen described as an “unusual condition.” He ordered five additional tests including a repeat MRI of the lumbar spine and an MRI of the head and cervical (upper) spine. He referred Mr. Henry to a neurologist specializing in autoimmune inflammatory disease.

March 14–15, 2010 — imaging. The head and cervical spine MRI was normal. The repeat lumbar spine MRI showed the same conus and cauda equina enhancement as the original January imaging. Dr. Hilarie Sheehan, the radiologist interpreting the March 15 MRI, noted that Mr. Henry was “not improving” and that the condition remained undiagnosed. Critically, her report observed that since the head and cervical spine had been evaluated, formal imaging of the thoracic spinal cord might also be warranted to exclude abnormality at that level.

March 23, 2010 — ER presentation with worsening. Mr. Henry returned to the Brampton Civic ER reporting “acute worsening” of the numbness and weakness in his left leg. He could now walk only with difficulty. He also reported episodes of difficulty voiding that had been occurring intermittently since late February. An ER physician examined him and discharged him for continued follow-up with Dr. Zaitlen.

The critical period: March 23 to July 20, 2010. Dr. Zaitlen received the March 14 and 15 MRI results, the Sheehan report (with its specific recommendation for thoracic imaging), and the March 23 ER record showing acute worsening. He took no action. He did not contact Mr. Henry or arrange for the patient to reattend. He did not order any further investigations. He did not order the thoracic MRI that Dr. Sheehan had specifically recommended.

Progressive deterioration. Over the following months, Mr. Henry’s symptoms worsened. He developed lower limb weakness, loss of bladder and bowel control, and pain and sensory disturbance extending up to the level of his umbilicus.

July 20, 2010 — paraplegia. Mr. Henry returned to Brampton Civic by ambulance, now paraplegic. Dr. Zaitlen was on vacation. A covering neurologist, Dr. Michael Angel, immediately conducted a lumbar puncture and ordered an MRI of the thoracic spine in light of “clear upper motor neuron features.” The radiologist (Dr. Robert Kurtz) found the MRI highly suspicious for a dural arteriovenous fistula in the mid-thoracic region. Another consulting neurologist (Dr. Brian Best) agreed. Mr. Henry was transferred to Toronto Western Hospital. On July 22, the diagnosis was confirmed by further imaging and consultation with an interventional neuroradiologist.

July 25, 2010 — surgical repair. The fistula was surgically repaired. Mr. Henry underwent rehabilitation and physical therapy and recovered some function. By 2019, however, his legs remained weak and spastic. He had difficulty walking, limited stamina, and required help over distance. He had severe bladder and bowel control problems, severe constipation, nerve pain in his legs and pelvis, and ongoing leg spasms. He continued to require ongoing therapy and medication. He had not returned to work.

The trial

Mr. Henry’s theory of liability was direct. Dr. Zaitlen breached the standard of care by failing to investigate the cause of the condition after receiving Dr. Sheehan’s March 15 report (with its specific recommendation for thoracic imaging) and the March 23 ER record (showing acute worsening). Had thoracic spinal cord imaging been performed at any time between March 2010 and July 2010, the SDAVF would have been detected. Earlier diagnosis would have allowed earlier surgical repair before paraplegia developed, and Mr. Henry would have recovered substantially more function.

Dr. Zaitlen’s defence was that he did not breach the standard of care. He pointed to the difficulty in diagnosing SDAVF, the rarity of the condition in a man of Mr. Henry’s age, the absence of specific clinical symptoms suggesting SDAVF before July 2010, and aspects of Mr. Henry’s presentation said to be inconsistent with this diagnosis. Alternatively, he argued that his failure to order thoracic imaging was, “at worst,” an error of judgment falling within the Wilson v Swanson, [1956] SCR 804, doctrine that mere error of judgment is not negligence.

The trial proceeded before a jury. After three days of deliberation, the jury returned a verdict in Mr. Henry’s favour and awarded just under $1.5 million in damages, comprising general damages, past income loss, future income loss, and future care costs.

The appeal

Dr. Zaitlen raised three grounds of appeal:

1. The jury’s finding that he breached the standard of care was unreasonable and unjust given the evidence at trial.
2. The jury’s answers revealed that it did not act judicially.
3. It was not open to the jury to make the future damages award that it did.

The appellate analysis

The Court of Appeal dismissed all three grounds.

On the standard of care finding. A jury could reasonably find that the neurologist breached the standard of care, relying on the evidence of the patient’s expert neurologist and rejecting the opinions of the appellant’s neurology experts. The appellate framework for jury verdicts is substantially deferential: the Court of Appeal does not retry the case on the cold record, but instead asks whether the verdict is one that a properly instructed jury could reasonably reach on the evidence.

The expert evidence at trial included neurologists testifying for both sides. The jury was entitled to accept the plaintiff’s expert and reject the defendants’ experts. Where the jury has been properly instructed and the evidence supports the verdict on at least one available line of analysis, the appellate court will not substitute its own assessment.

On the jury’s reasoning. The Court of Appeal approached the jury’s answers holistically and found a rational chain of reasoning.

On standard of care, the jury made a general observation that Dr. Zaitlen did not continue to investigate from March to June 2010, and then identified the specific failures: he should have communicated with Mr. Henry and ordered thoracic imaging.

On causation, the jury began by identifying the consequences of the breach as “delay in diagnosis, lack of communication, instruction and planning.” It then considered the impact on Mr. Henry in the short term. It concluded that had the diagnosis been made before June 2010, Mr. Henry would have been in a more favourable position for treatment and recovery with likely fewer deficits.

This is doctrinally important. The jury’s causation reasoning satisfies the Clements v Clements, 2012 SCC 32, but-for test in its temporal application: but for the breach (delayed diagnosis), Mr. Henry would have had a better outcome (more favourable position with fewer deficits). The “more favourable position” framing tracks the established Canadian jurisprudence on delayed diagnosis causation. This is not a “loss of chance” analysis (which Canadian common law has rejected) — it is a substantive causation finding that the breach made the bad outcome worse than it would otherwise have been, on a balance of probabilities.

On the future damages award. It was open to the jury to find, on the evidence, that Mr. Henry was able to return to work full-time at some point after surgery but would retire early as a result of the residual disability. The future income loss award rested on the premise that Mr. Henry had expected to work until age 68 and would now retire at age 57 — eleven years of foregone working life. This is a reasonable inference on the evidence and the appellate court would not disturb it.

The “failure to investigate” SOC framework

The doctrinal centerpiece of Henry v Zaitlen is the “failure to investigate” framework for standard of care analysis. This is doctrinally distinct from the more familiar misdiagnosis or wrong-treatment frames. The framework operates as follows:

• A patient has an undiagnosed condition with progressive or persistent symptoms
• Initial workup has narrowed the differential but not produced a diagnosis
• A specific suggestion has emerged for further investigation (here, the radiologist’s thoracic MRI recommendation)
• New clinical information indicates worsening (here, the ER worsening report)
• The treating specialist takes no action — no further investigation, no communication with the patient, no reassessment

The framework holds that sustained inaction in the face of mounting evidence requiring response can itself constitute a breach of the standard of care. The breach is not about choosing the wrong diagnosis or the wrong treatment; it is about failing to continue investigating when continued investigation was the obvious next step.

This framework is particularly important in cases of rare conditions like SDAVF. The defence argument in such cases is often that the condition was rare and difficult to diagnose, and that not all specialists would have arrived at the correct diagnosis quickly. The “failure to investigate” framework responds: the question is not whether a reasonable specialist would have diagnosed the rare condition. The question is whether a reasonable specialist would have continued investigating until a diagnosis was reached. Where a specific imaging suggestion has been made by a consulting radiologist, the standard of care for the treating specialist includes acting on that suggestion or providing a documented reason for not doing so.

In Henry, Dr. Zaitlen had:

• A specific imaging suggestion from a consulting radiologist
• New evidence of clinical worsening from the ER
• An undiagnosed and progressive condition
• No alternative working diagnosis being pursued

His response — taking no action between March 23 and July 20 — fell short of what a reasonable neurologist would have done. The jury so found. The Court of Appeal would not disturb that finding.

Why the “error of judgment” defence failed

The Wilson v Swanson, [1956] SCR 804, principle is foundational in Canadian medical malpractice. Mere error of judgment is not negligence. A physician who exercises reasonable judgment in a difficult clinical situation does not breach the standard of care merely because the judgment turns out, with hindsight, to have been wrong. The standard requires reasonable conduct, not perfect outcomes.

Dr. Zaitlen argued that his failure to order thoracic imaging was “at worst” an error of judgment falling within Wilson v Swanson. The argument failed because the framework requires the underlying judgment to have actually been exercised reasonably. In Wilson, the surgeon faced a difficult intraoperative decision and made a clinical judgment that the appellate court ultimately found defensible. The defence operates where there is evidence of:

• An active clinical assessment
• Consideration of available alternatives
• A reasoned choice based on the clinical information
• Documentation of the reasoning

What the defence does not protect is sustained inaction in the face of mounting evidence requiring response. Where the specialist has not actively reassessed, has not considered alternatives, and has simply allowed time to pass without action, there is no “judgment” being exercised — and Wilson v Swanson does not apply. The framework protects clinical judgment, not clinical neglect.

In Henry, the jury’s findings showed sustained inaction over nearly four months. Dr. Zaitlen had received the radiologist’s recommendation, had received the ER worsening report, and had taken no action in response. This is not the kind of considered clinical judgment Wilson v Swanson protects.

Communication as part of the standard of care

A distinctive feature of the Henry jury verdict is the express identification of “lack of communication, instruction and planning” as part of the breach. This is doctrinally significant.

The standard of care for a treating specialist is not limited to clinical actions like ordering tests and prescribing treatment. It extends to:

• Communicating with the patient about the suspected diagnoses and the planned investigation
• Providing instructions about when symptoms warrant re-presentation
• Maintaining a planning framework for ongoing follow-up
• Responding to information received about the patient’s clinical course

A specialist who receives an ER report showing patient worsening and does not contact the patient — does not call, does not bring the patient back for assessment, does not adjust the investigation plan — is failing a communication standard that is part of the broader SOC. The jury in Henry recognized this expressly. The Court of Appeal did not disturb it.

For practising specialists, the operational lesson is that receiving clinical correspondence about a patient (ER reports, consultant reports, imaging reports) is not a passive function. It is part of the ongoing duty of care. Reports that show worsening or that contain specific recommendations require active response — at minimum, documented consideration and a documented decision about next steps.

The appellate cluster — seven cases, one plaintiff affirmance

Henry v Zaitlen is the seventh case in the rewritten appellate cluster on this site and the first appellate affirmance of a plaintiff jury verdict:

• Willick v Willard (Court of Appeal for Ontario): affirmance with deferential review; defendant won at trial
• Hanson-Tasker v Ewart (Court of Appeal for British Columbia): affirmance on competing experts and Snell discretion; defendant won at trial
• Dumesnil v Jacob (Manitoba Court of Appeal): new trial; defendant won at trial
• Penate v Martoglio (Court of Appeal for Ontario): new trial; defendant won at trial
• Rybakov v Khattak (Court of Appeal for British Columbia): affirmance on expert evidence requirement; defendant won at trial
• Focken v Miller (Court of Appeal for British Columbia): affirmance on judicial humility; defendant won at trial
• Henry v Zaitlen (Court of Appeal for Ontario): affirmance; plaintiff won at trial

The seven cases now cover the full spectrum of appellate outcomes in malpractice practice: affirmance with deferential review on defendant trial wins, intervention on substantive error of law, intervention on procedural defects, affirmance on expert evidence questions, and affirmance of a substantial plaintiff jury verdict. For Ontario and cross-province appellate practice, this is a useful comprehensive reference set.

The plaintiff wins sub-grouping

Henry v Zaitlen is the second clean plaintiff win in the rewritten case-comment cluster:

• Kotorashvili v Lee (Ontario, trial level): premature hardware removal in orthopaedic surgery; $35,000 general damages
• Henry v Zaitlen (Ontario, trial + appellate): failure to investigate progressive neurological symptoms; ~$1.5 million jury award

The two cases together illustrate the range of plaintiff outcomes:

• Kotorashvili: bench trial; clear documentary record of deviation from own plan; modest damages reflecting limited long-term impact
• Henry: jury trial with appellate affirmance; failure to investigate in face of clinical worsening; substantial damages reflecting catastrophic injury with partial recovery

Different fact patterns, different procedural postures, different damages calibrations — but both clean plaintiff wins. The sub-grouping provides important balance to the cluster’s many causation/SOC defeat cases.

The missed-diagnosis cluster

Henry v Zaitlen is also a significant addition to the missed-diagnosis cluster:

• Five Dangerous ER Misdiagnoses: master patient guide
• Stroke Misdiagnosis: clinical and legal framework
• Cancer Misdiagnosis
• Sepsis
• Ectopic Pregnancy
• Cauda Equina
• Sutherland v Booth (stroke causation defeat)
• Tripp v Ross (cancer causation defeat)
• Henry v Zaitlen (this case — successful plaintiff outcome in SDAVF case)

The cluster now includes Henry as a successful plaintiff outcome in a rare condition diagnostic delay case. This is important balance — the other missed-diagnosis case comments (Sutherland, Tripp) are causation defeats. Henry shows what successful diagnostic delay litigation looks like.

The case also resonates with the Cauda Equina patient guide because the initial presentation involved cauda equina nerve root enhancement on MRI. The condition itself turned out to be more rostral (thoracic spine fistula), but the diagnostic and management framework for progressive lower neurologic symptoms is similar.

The doctrinal lessons

The case stands for several propositions.

Failure to investigate can be the breach. The standard of care extends beyond choosing the right diagnosis or treatment to continuing investigation when the diagnosis remains uncertain and the patient’s condition is not resolving. Sustained inaction in the face of mounting clinical evidence can itself constitute breach.

Specific imaging suggestions from consulting radiologists deserve action. When a radiologist’s report specifically recommends further imaging (here, the thoracic MRI suggestion), the treating specialist’s standard of care includes acting on the recommendation or providing a documented reason for not doing so.

Communication is part of the SOC. Receiving clinical correspondence about a patient is an active duty. ER worsening reports require response. The standard of care includes contacting the patient, adjusting the investigation plan, and documenting next steps when the clinical picture changes.

The “error of judgment” defence requires actual judgment. Wilson v Swanson protects clinical decisions made with reasonable consideration of available information. It does not protect sustained inaction. Where the specialist has not actively reassessed and has not made a documented decision about next steps, there is no judgment to protect.

Appellate review of jury verdicts is deferential. Jury verdicts are reviewed for whether they are reasonable on the evidence and whether the jury’s answers show a rational chain of reasoning. The Court of Appeal does not retry the case on the cold record. This deference applies in both directions — but in practice, plaintiff verdicts that survive appeal often involve clear evidentiary support for both breach and causation.

Delayed diagnosis causation is established when earlier diagnosis would have produced a better outcome. The Clements v Clements but-for test operates in a temporal frame. The jury’s framing of “more favourable position for treatment and recovery with likely fewer deficits” satisfies the test on a balance of probabilities. This is not “loss of chance” — it is substantive causation.

Catastrophic injury damages can be substantial. ~$1.5 million reflects the realistic value of a working-age catastrophic spinal cord injury with partial recovery: general damages, past income loss, future income loss based on early retirement, and future care costs. The methodology is standard malpractice damages calibration applied to severe but not maximal disability.

Why this case matters

For prospective clients. Henry v Zaitlen illustrates what successful malpractice cases involving progressive conditions look like. The features here are: a treating specialist with continuing responsibility for diagnostic investigation; a documented suggestion for further investigation that was not followed; clinical worsening that should have prompted reassessment; and a catastrophic outcome that would likely have been substantially mitigated by earlier diagnosis. Where these features are present, plaintiff outcomes become realistic. For more on the realistic assessment of malpractice claims, see Suing for Medical Malpractice in Ontario: What You Need to Know and Six Common Misunderstandings About Medical Malpractice.

For plaintiff counsel. The case provides several useful precedents. The “failure to investigate” framework is a clean theory of breach that can succeed where misdiagnosis or wrong-treatment theories might not. Documented radiologist recommendations that were not followed are powerful evidence of breach. ER worsening reports that were ignored are similarly powerful. The communication-as-SOC framing opens additional theories of breach beyond the strictly clinical. The appellate deference to plaintiff jury verdicts means well-supported trial victories are durable.

For defence counsel. The case is a reminder of the structural problem with the “rare condition” defence in delayed diagnosis cases. The plaintiff’s theory need not be that the specialist should have made the rare diagnosis immediately; it need only be that the specialist should have continued investigating until the diagnosis was made. Where specific recommendations from consultants were not followed, and where new clinical information was not acted upon, the rare-condition defence does not fully respond to the plaintiff’s actual theory.

For practising neurologists and other specialists managing complex undiagnosed conditions. The case is a substantial professional lesson. Where a patient has progressive or persistent symptoms of unknown cause:

• Continue investigating until the diagnosis is reached or all reasonable investigations have been exhausted
• Act on specific recommendations from consulting radiologists or other specialists, or document the reasons for not acting
• Respond to clinical correspondence about the patient (ER reports, consultant reports) — receiving the correspondence is the beginning, not the end, of the duty
• Maintain active communication with the patient about the investigation plan and what symptoms warrant re-presentation
• Document the clinical reasoning when investigations are deferred or alternatives are considered

For more on Ontario neurological malpractice generally, see Stroke Malpractice Lawyer in Toronto and Misdiagnosis Lawyer in Toronto.

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Decision Date: April 5, 2024 (appellate); trial verdict in late 2021

Jurisdiction: Court of Appeal for Ontario

Citation: Henry v Zaitlen, 2024 ONCA 243 (CanLII)

Outcome: Plaintiff jury verdict (~$1.5 million) affirmed on appeal. General damages, past income loss, future income loss (with early retirement assumption), and future care costs.

Key authorities: Wilson v Swanson, [1956] SCR 804 (error of judgment doctrine); Crits v Sylvester, [1956] OR 132 (CA), aff’d [1956] SCR 991 (standard of care); ter Neuzen v Korn, [1995] 3 SCR 674 (expert evidence requirement); Clements v Clements, 2012 SCC 32 (but-for causation); Athey v Leonati, [1996] 3 SCR 458 (multiple causes framework)