Wallace v Kam was a medical negligence case concerned with the failure to warn.
Mr Wallace sought medical assistance in relation to a lumbar spine condition.
Dr Kam, a neurosurgeon, performed a surgical procedure on him, which had inherent risks.
- One risk was of temporary local damage to nerves within his thighs, described as “bilateral femoral neurapraxia”, resulting from lying face down on the operating table for an extended period.
- Another, distinct risk was a one-in-twenty chance of permanent and catastrophic paralysis resulting from damage to his spinal nerves.
Dr Kam did not warn Mr Wallace of either of the risks.
The first risk materialised and Mr Wallace sustained neurapraxia, which left him in severe pain for some time.
Mr Wallace claimed that Dr Kam negligently failed to warn him of the risks and that, had he been warned of either risk, he would have chosen not to undergo the surgical procedure and would therefore not have sustained the neurapraxia.
At the initial trial however, it was held that evidence indicated that only the second, more serious risk, would have prevented Mr Wallace from proceeding with the operation.
At trial, in the Supreme Court, Justice Harrison found that although there had been a breach in that there was a failure to warn about the risk of local temporal damage to the nerves, that failure was not a necessary condition of the occurrence of the neurapraxia, and as such was not the cause of Mr Wallace’s injury. (See Wallace v Ramsay Health Care Ltd  NSWSC 518)
Mr Wallace appealed to the Supreme Court of Appeal, where his action again failed. The Court of Appeal tested his arguments by assuming that Dr Kam negligently failed to warn Mr Wallace of the risk of paralysis and that, if warned of that risk, Mr Wallace would not have undergone the surgical procedure. They asked, on that assumption, whether Dr Kam was liable for the neurapraxia. The Court of Appeal divided in answering that question. The majority, Allsop P and Basten JA, answered it in the negative, and dismissed the appeal. Beazley JA answered it in the affirmative and would have ordered a new trial. (See Wallace v Kam  NSWCA 82)
Mr Wallace appealed to the High Court.
The High Court delivered a unanimous judgement.
It held that the negative answer of the majority of the Court of Appeal was to be preferred, and that Mr Wallace’s appeal to the High Court, which raised the same question, should therefore be dismissed.
Factual causation was made out as :
The case in respect of factual causation falls squarely within the second of the factual scenarios already discussed: if warned of all material risks, Mr Wallace would have chosen not to undergo the surgical procedure at all and would therefore not have sustained the neurapraxia.
However,the critical question was one of scope of liability.
In this regard, the question was whether Dr Kam’s liability extended to the physical injury in fact sustained by Mr Wallace in circumstances where Mr Wallace would not have chosen to undergo the surgical procedure had he been properly warned of all material risks but where he would have chosen to undergo the surgical procedure had he been warned only of the risk that in fact materialised?
The Court held that the answer to this was no.
Scope of liability was not made out because ‘the normative judgment that is appropriate to be made is that the liability of a medical practitioner who has failed to warn the patient of material risks inherent in a proposed treatment should not extend to harm from risks that the patient was willing to hazard, whether through an express choice or as found had their disclosure been made.’ .
The Appeal was dismissed with costs.