No liability for materialisation of inherent risk*

Legal Directions

The New South Wales Court of Appeal has dismissed the appeal of a stroke victim who sought to claim damages from a radiologist for failing to diagnose an aneurysm three years before she underwent an operation which caused its rupture. Unanimously, the Court held that this rupture was the materialisation of an ‘inherent risk’ that could not be avoided by the exercise of ‘reasonable care and skill’, and accordingly there could be no liability attributed to the radiologist pursuant to s5I of the Civil Liability Act 2002 (NSW).


Christine Paul, the plaintiff, was diagnosed with a brain aneurysm in 2006. She subsequently decided to undergo an operation to remove it with a view to avoiding the risk of a spontaneous rupture. During the operation, however, this very risk materialised (without any failure to warn, or lack of care or skill on the part of the operating surgeons) and Ms Paul suffered a stroke. She brought proceedings in the Supreme Court of New South Wales against Dr Cook, a radiologist who had failed to diagnose the aneurysm three years earlier following an angiogram (at which time it was the same size and shape as it was in 2006). The doctor admitted he breached his duty of care to Ms Paul and damages of $1 million were agreed between the parties. However, causation was in issue.

At first instance

It was argued on behalf of Ms Paul that, if the doctor had properly identified the aneurysm in 2003, she would have undergone an operation to remove it earlier and, statistically, she would not have suffered the rupture (as the likelihood of the risk materialising during the procedure was in the range of 1-2%). Drawing upon s5I of the CLA, the doctor argued he could not be liable in negligence for the materialisation of an inherent risk which could not be avoided by the exercise of reasonable care and skill.

Justice Brereton rejected the interpretation of s5I advanced on behalf of the doctor and held that the phrase ‘reasonable care and skill’ referred to that of the doctor, not ‘some subsequent intervenor’. However, his Honour went on to dismiss Ms Paul’s claim on the basis that it was not appropriate for the doctor’s liability to extend to her injuries, pursuant to s5D(1)(b) of the Civil Liability Act (CLA) (that is, the ‘scope of liability’ element of causation).

On appeal

Ms Paul appealed Justice Brereton’s decision. The Court of Appeal comprising Justices Basten, Leeming and Ward, unanimously dismissed the appeal, holding that causation had not been established. Their Honours also found that, in the circumstances of this case, Justice Brereton’s construction of s5I was too restricted. Indeed, their Honours considered that s5I was the preferable basis upon which to conclude that the doctor could not be liable for Ms Paul’s harm.

Justices Basten and Ward agreed with Justice Leeming’s reasons in relation to the correct interpretation and application of s5I in the circumstances. As a preliminary point the Court noted that the effect of sections like s5I is to provide a complete answer to any claim for damages (whether it be in tort, contract, or otherwise) arising out of a failure to exercise reasonable care and skill. The presence of the phrase ‘as a result of’ in s5I(1), as distinct from ‘caused by’ or ‘arising from’ (which is seen elsewhere in Part 1A), reveals that s5I deals with the broader, legal concept of liability and its connection with a defendant’s conduct (rather than the causal connection between that conduct and a plaintiff’s harm). That is, once it is established that the particular harm suffered by a plaintiff has arisen as a result of the materialisation of an inherent risk (a risk that could not be avoided by the exercise of reasonable care and skill), then there is no liability for that harm.

His Honour went on to address Justice Brereton’s restricted interpretation of ‘inherent risk’ to mean something that could not have been avoided by Dr Cook’s reasonable care and skill. This was potentially correct where there was a relationship between the act of negligence and the exposure to the inherent risk, such as when a patient is harmed by the materialisation of an unavoidable risk from treatment which the patient only underwent by reason of a negligent diagnosis. However, there was no such relationship in this case. The risk that materialised in Ms Paul’s case could not have been avoided by reasonable care on the part of the doctor – if Ms Paul chose to undergo surgery the risk that the aneurysm would rupture was always present. Whether she chose to have the operation in 2003 or in 2006 (as was the case), the risk could not be avoided by reasonable care and skill. Accordingly, there was no causal link between the doctor’s negligence and Ms Paul’s harm. The doctor could not be held liable.


While Justices Basten and Leeming confirmed that s5I would have no application where negligence causes exposure to an inherent risk (in keeping with the common law, as exemplified by the decision of the High Court of Australia in Mahony v Kruschich (Demolitions) Pty Ltd), their Honours declined to consider how s5I would operate where negligence increases an inherent risk. It appears as though the primary consideration will be both the existence, and proximity, of a relationship between the failure to exercise reasonable care and skill and the exposure to an inherent risk.

This decision clarifies that, when looking to apply s5I in a causation argument, it is not necessary to establish that the materialisation of an inherent risk could not have been avoided by reasonable care and skill on the part of the defendant. To use the words of Justice Brereton, the relevant care and skill may be that of a ‘subsequent intervenor’. As a result, s5I has the potential to be applied quite broadly.

*Paul v Cooke [2013] NSWCA 311

Authored by Gabrielle Watts, Lawyer, Sydney.

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