Chester v. Afshar

Factual and Procedural Background

The Plaintiff experienced chronic lower-back pain from 1988 onwards. After years of conservative treatment by a rheumatologist, imaging revealed significant disc protrusions. In November 1994 the rheumatologist referred the Plaintiff to the Defendant, an experienced neurosurgeon, who advised elective lumbar surgery and performed it three days later. The procedure was carried out with due technical skill but resulted in cauda equina syndrome, leaving the Plaintiff partially paralysed.

The trial judge found no operative negligence but held that the Defendant had breached a duty to warn the Plaintiff of a 1–2 % inherent risk of serious neurological damage. Although the judge could not say the Plaintiff would never have consented to surgery, he found she would at least have postponed it to seek more information. Judgment was entered for the Plaintiff. The Court of Appeal affirmed. The Defendant appealed to the ultimate appellate court.

Legal Issues Presented

1. Whether a doctor’s negligent failure to warn a patient of a small but inherent surgical risk can be treated as the legal cause of the ensuing injury when the patient cannot prove she would ultimately have refused the operation.
2. Whether traditional “but-for” causation should be modified in informed-consent cases so that breach and materialisation of the warned-about risk suffice for liability.
3. Whether public-policy considerations concerning patient autonomy justify such a modification.

Arguments of the Parties

Defendant's Arguments

• Causation in negligence requires proof that, but for the breach, the injury would probably not have occurred; the Plaintiff could not show she would have declined surgery altogether.
• Failure to warn did not increase the risk; the same 1–2 % chance would have existed whenever and by whoever the surgery was performed.
• Creating liability without proof of increased risk would make doctors insurers against inherent surgical hazards.

Plaintiff's Arguments

• The Defendant’s duty was to protect the Plaintiff’s right to make an informed choice; breach of that duty combined with realisation of the very risk about which she should have been warned is sufficient causation.
• If properly warned, the Plaintiff would have postponed the procedure, sought other opinions, and the statistical likelihood of this specific injury on a later occasion was extremely small.
• Policy considerations supporting patient autonomy warrant a narrow but necessary departure from orthodox causation rules.

Table of Precedents Cited

Court's Reasoning and Analysis

Five Law Lords delivered separate opinions. A majority (Judge Steyn, Judge Hope, and Judge Walker) endorsed a limited departure from traditional causation:

• The core purpose of the warning duty is to safeguard patient autonomy; without an effective remedy that purpose is undermined.
• The injury suffered was the very risk about which the Defendant was obliged to warn. That intimate nexus justifies treating breach and injury as causally linked.
• Policy considerations—respect for personal autonomy and maintenance of public confidence—support a “narrow and modest” relaxation of the “but-for” rule, analogous to the approach in Fairchild.

The minority (Judge Bingham and Judge Hoffmann) would have allowed the appeal:

• Traditional causation was not satisfied; the Plaintiff could not prove she would ultimately have refused surgery.
• Failure to warn did not increase the risk; imposing liability would improperly make physicians insurers of unavoidable surgical hazards.
• Vindication of autonomy might justify nominal relief, but not full compensatory damages for physical injury.

Holding and Implications

Appeal dismissed. The Plaintiff is entitled to damages for the neurological injury.

Implications: The ruling recognises an exception to strict “but-for” causation in informed-consent litigation. Where a patient suffers the very injury about which a warning was required, courts may treat breach and injury as causally connected even absent proof the patient would never have consented. The decision strengthens patient autonomy but is expressed as a “narrow and modest” doctrinal modification rather than a wholesale replacement of causation principles.