Yesterday the High Court delivered
judgment in Wallace v Kam, and
important case addressing causation in the context of a failure to warn by a
medical practitioner.
Mr
Wallace sought medical assistance in relation to a condition of his lumbar
spine. Dr Kam, a neurosurgeon, performed a surgical procedure on him. The
surgical procedure 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. The
surgical procedure was unsuccessful: the condition of Mr Wallace's lumbar spine
did not improve. The first risk materialised: Mr Wallace sustained neurapraxia
which left him in severe pain for some time. The second risk did not.
Mr
Wallace claimed damages from Dr Kam for the neurapraxia he sustained. Mr
Wallace's claim in the Supreme Court of New South Wales was that Dr Kam
negligently failed to warn him of risks including the risk of neurapraxia and
the risk of paralysis 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.
The
trial judge found that Dr Kam negligently failed to warn Mr Wallace of the risk
of neurapraxia. But he also found that Mr Wallace would have chosen to undergo
the surgical procedure even if warned of the risk of neurapraxia. Because it was that risk which actually
materialized, the question of whether Dr Kam had negligently failed to warn Mr
Wallace of the risk of paralysis was irrelevant.
In
the Court of Appeal Allsop P and Basten JA held that even if 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, nonetheless
he was not entitled to damages for the neurapraxia. Beazley JA held to the contrary, noting that
had he been warned of the risk of paralysis, the surgery (and hence the
neurapraxia) would not have occurred.
The
High Court unanimously rejected Mr Wallace’s appeal. The Court held that the question of liability
for the neurapraxia was to be answered by application of section 5D of the Civil Liability Act 2002. That section divided the causation issue into
two elements: factual causation (ie was the negligence was a necessary condition
of the occurrence of the harm - a straightforward “but for” test) and scope of liability (ie is it appropriate
for the scope of the negligent person's liability to extend to the harm so
caused).
The
High Court held that a medical practitioner’s duty of care was a single
comprehensive duty to exercise reasonable care and skill in the provision of
advice and treatment. A component of
that single duty of care is to warn a patient of “material risks” inherent in a
proposed treatment. On the assumptions
being made for the purposes of deciding the case, that duty was breached by the
failure to warn of the risk of paralysis and the neurapraxia, and had Mr
Wallace been warned of the risk of paralysis he would not have undergone the
surgery.
In
this case, the factual causation question was clearly and straight-forwardly
answered in the affirmative. The failure
to warn of the risk of paralysis was a necessary condition of the neurapraxia
sustained by Mr Wallace.
More
difficult, however, was the “scope of liability” question. The duty of a medical practitioner to warn
the patient of material risks inherent in a proposed treatment is imposed by
reference to the underlying common law right of the patient to choose whether
or not to undergo a proposed treatment.
Beazley JA had considered it was appropriate to impose liability in this
case because to do so would promote that objective. However, the High Court held that the policy
underlying the requirement that a doctor exercise of reasonable care and skill
in warning of material risk is neither to protect that right to choose nor to
protect the patient from exposure to all unacceptable risks. The underlying
policy is rather to protect the patient from the occurrence of physical injury
the risk of which is unacceptable to the patient. It is therefore appropriate
that the scope of liability for breach of the duty reflect that underlying
policy. Accordingly, in terms of section
5D, it was not appropriate for the scope of liability to extend to the harm (neurapraxia)
that Mr Wallace was willing to accept asa consequence of the surgery.
The
position of Mr Wallace in respect of the neurapraxia when considered for the
purposes of causation was in principle no different from what his position
would have been had Dr Kam properly warned him of the risk of neurapraxia and
had he made an express choice to proceed with the surgical procedure in light
of that warning. He was not to be compensated for the occurrence of physical
injury the risk of which he was prepared to accept.
