Wallace v Kam

[2012] NSWCA 82

Court of Appeal

New South Wales

Case Title:

Wallace v Kam

Medium Neutral Citation:

[2012] NSWCA 82

Hearing Date(s):

19 September 2011

Decision Date:

13 April 2012

Jurisdiction:

Before:

Allsop P at [1]; 
Beazley JA at [35]; 
Basten JA at [156]

Decision:

Appeal dismissed with costs.

[Note: The Uniform Civil Procedure Rules 2005 provide (Rule 36.11) that unless the Court otherwise orders, a judgment or order is taken to be entered when it is recorded in the Court's computerised court record system. Setting aside and variation of judgments or orders is dealt with by Rules 36.15, 36.16, 36.17 and 36.18. Parties should in particular note the time limit of fourteen days in Rule 36.16.]

Catchwords:

TORTS - NEGLIGENCE - medical practitioner - duty to warn patient of material risks inherent in proposed surgery - multiple material risks - whether warning was required

TORTS - NEGLIGENCE - medical practitioner - causation - whether failure to warn of material risk that did not eventuate causally connected to injury - Civil Liability Act 2002, s 5D

Legislation Cited:

Civil Liability Act 2002

Cases Cited:

Adeels Palace Pty Ltd v Moubarak; Adeels Palace Pty Ltd v Bou Najem [2009] HCA 48; 239 CLR 420
Bennett v Minister of Community Welfare [1992] HCA 27; 176 CLR 408
Canterbury v Spence 464 F 2d 772, 150 U.S.App.D.C. 263 (1972)
Cattanach v Melchior [2003] HCA 38; 215 CLR 1
Chappel v Hart [1998] HCA 55; 195 CLR 232
Chester v Afshar [2004] UKHL 41; [2005] 1 AC 134
Cochran v Wyeth 3 A 3d 673 (Pa Super, 2010)
Downer v Veilleux 322 A 2d 82 (Me. 1974)
Ellis v Wallsend District Hospital (1989) 17 NSWLR 553
Environment Agency v Empress Car Co (Abertillery) Ltd [1998] UKHL 5; [1999] 2 AC 22
Faulkner v Keffalinos [1970] 45 ALJR 80
Hopp v Lepp [1980] 4 W.W.R. 645, 13 C.C.L.T. 66, 32 N.R. 145, 22 A.R. 361
Hughes v Lord Advocate [1963] UKHL 1; [1963] AC 837
March v Stramare (E & M H) Pty Ltd [1991] HCA 12; 171 CLR 506
Modbury Triangle Shopping Centre v Anzil [2000] HCA 61; 205 CLR 254
Moyes v Lothian Health Board 1990 S.L.T. 444
Pledge v RTA [2004] HCA 13; 205 ALR 56
Reibl v Hughes [1980] 2 S.C.R. 880, 14 C.C.L.T.1, 114 D.L.R. (3d) 1, 33 N.R. 361, J.E. 80-894
Rogers v Whitaker [1992] HCA 58; 175 CLR 479
Rosenberg v Percival [2001] HCA 18; 205 CLR 434
Sidaway v. Governors of Bethlem Royal Hospital [1985] AC 871
Strong v Woolworths Ltd [2012] HCA 5
Tame v NSW [2002] HCA 35; 211 CLR 317
Travel Compensation Fund v Tambree [2005] HCA 69, 224 CLR 627

Texts Cited:

Gerd Gigerenzer in Reckoning with Risk (Penguin, 2002)
HLA Hart and Tony Honoré, Causation in the Law, 2nd ed (1985)
Michael S Moore, Causation and Responsibility: An Essay in Law, Morals and Metaphysics (OUP, 2010), p 101
Weinrib, "A Step Forward in Factual Causation" (1975) 38 Modern Law Review 518

Category:

Principal judgment

Parties:

Ian Wallace (Appellant)
Andrew Kam (Respondent)

Representation

- Counsel:

P Bates;  P White (Appellant)
D J Higgs SC;  M Fordham (Respondent)

- Solicitors:

Gerard Malouf & Partners (Appellant)
Tresscox Lawyers (Respondent)

File number(s):

CA 2007/265252

Decision Under Appeal

- Court / Tribunal:

- Before:

Harrison J

- Date of Decision:

09 July 2010

- Citation:

Wallace v Ramsay Health Care [2010] NSWSC 518

- Court File Number(s)

SC 20412/07

Publication Restriction:

HEADNOTE

[This headnote is not to be read as part of the judgment]

The appellant underwent fusion to alleviate pain caused by an intervertebral disc protrusion in his lumbar spine. After the surgery, the appellant suffered bilateral femoral neurapraxia, or local nerve damage to the thighs. The appellant brought proceedings against the respondent neurosurgeon who performed the surgery, seeking damages in relation to the respondent's failure to warn of the material risks of the operation, namely, the risk of bilateral femoral neurapraxia and a 5 per cent risk of paralysis.

The trial judge held that the respondent breached his duty of care to the appellant by failing to warn of the material risk of bilateral femoral neurapraxia. However, his Honour held that the appellant did not establish that he would have declined the surgery if warned of that risk. Relevantly, his Honour did not make a finding of whether the 5 per cent risk of paralysis was a material risk, which the respondent was under a duty to disclose to the appellant, nor whether he would have declined the operation if warned of that risk. He treated the risk which did not materialise as irrelevant.

The appellant appealed against his Honour's judgment for the respondent.

The issue for determination was whether the trial judge erred (a) in failing to consider a risk that did not eventuate, but might, had an appropriate warning been given, have led the plaintiff not to have the operation and (b) in finding that the only relevant breach of duty was the failure to warn of the risk that in fact materialised, but where a warning would not have led the plaintiff to decline an operation.

Held per Allsop P dismissing the appeal (Basten JA agreeing in part):
(1) The task involved in s 5D(1)(a) is to determine the factual connection between the negligence and the occurrence of the particular harm. It does not incorporate policy or value judgments: [4].
Cited: Strong v Woolworths Ltd

(2) In the circumstances of this case, the enquiry required by s 5D(1)(a) was a full factual analysis of what Dr Kam did and did not say and what Mr Wallace would have done. This was not undertaken: [2], [9].

(3) It is only possible for this Court to resolve the matter by assuming Mr Wallace was not warned of the risk of paralysis and, if so warned, would not have undergone the operation: [11].

(4) In order for a conclusion under s 5D(1)(b) that the scope of liability should not extend, there needs to be a conclusion of the tenuousness of the factual link or some limitation by reference to the rule of responsibility involved. Here, the duty and the rule of responsibility under s 5D(1)(b) are to protect the patient from harm from material inherent risks that are unacceptable to him or her: [12]-[14].

Considered: Rosenberg v Percival; March v Stramare (E & MH) Pty Ltd; Chappel v Hart; Environment Agency v Empress Car Co (Abertillery) Ltd

(5) Where the risks can be seen as separate and distinct, recovery is limited to risks coming home that were material and that should have been disclosed and that were not acceptable to the patient: [18]-[19], [23].

Considered: Rosenberg v Percival

Held per Beazley JA (dissenting):
(1) The question of the materiality of risks is determined objectively in all the circumstances. Whether a risk of a 5 per cent chance of a catastrophic outcome is a material risk is a question of fact for the determination of the trial judge: [67].

Considered: Rogers v Whitaker; Rosenberg v Percival

(2) An undisclosed risk, which is one of a 'cluster of risks', does not need to materialise in order to establish a causative link between the breach of the duty to warn of material risks and the harm suffered: [138].

Distinguished: Rosenberg v Percival

Considered: Hughes v Lord Advocate; Chester v Afshar; Reibl v Hughes; Canterbury v Spence; Downer v Veilleux

Applied: Ellis v Wallsend District Hospital

(3) The trial judge erred in finding that the duty to warn of material risks was confined to the risk of neurapraxia: [151].

(4) The concepts of duty of care and causation are interrelated and any determination of causation must be made with regard to the nature and scope of the relevant duty of care. The statutory principles do not abrogate this relationship: [111], [147]-[148].

Cited: Chappel v Hart; Rosenberg v Percival

(5) The question of whether the warning of the risk of paralysis was in fact given involves questions of fact and it is not appropriate for this court to engage in fact finding on this point: [152]-[153].

Held per Basten JA dismissing the appeal:
(1) Any attempt to treat elements of causation as entirely separate and distinct is doomed to fail in contestable cases, as is a rigid compartmentalisation of duty, breach and causation: [164].

Cited: Rosenberg v Percival

(2) As a matter of principle, if the purpose of requiring payment of compensation is to require the defendant to bear the cost of the harm eventuating from his or her negligent conduct, it is far from clear why that burden should be imposed in circumstances where the harm could only have arisen from breach of another element of the duty: [173].

(3) It is hard to identify a principled basis upon which a medical practitioner should be made legally responsible to pay compensation to a person who suffered an adverse outcome as to which he or she had been properly advised and had accepted: [174].

(4) The failure to warn of the risk which came to pass was not a physical condition necessary for the occurrence of harm, so that aspect of the negligence of the respondent was not a relevant cause of the harm: [175].

JUDGMENT

1. ALLSOP P: I have had the great benefit of reading in draft the reasons of Beazley JA and Basten JA. Though relatively simple in its primary factual matrix, this case reveals the subtleties and difficulties that underlie questions of causation. I have not found the resolution of the case easy. That difficulty stems from the fulcrum around which the question of liability turns: the value judgment involved in deciding whether it is appropriate that Dr Kam should be liable for the harm caused by the manifestation of neurapraxia. I have come to the view that it is not appropriate. I differ somewhat from Basten JA in concluding why the appeal should be dismissed. Given the comprehensive discussion by Beazley JA of the background, facts and authorities, for which I am grateful, I am able to state my reasons shortly.

2. The reasons of the primary judge were, if I may say so, clear, concise and precise. His Honour set out the framework of the causal analysis by reference to the Civil Liability Act 2002 (NSW), s 5D. In my respectful view, however, though his Honour reached the correct conclusion, the analysis by which he reached his conclusion paid insufficient regard to the structure of analysis required by s 5D. In particular, I disagree with his Honour's approach to s 5D(1)(a). The difference in my approach to that adopted by the primary judge broadly conforms to the difference of approach I have to that primarily adopted by Basten JA. In the circumstances of this case, the enquiry required by s 5D(1)(a) required a full factual analysis of what Dr Kam did and did not say and what Mr Wallace would have done. The limitation on the scope of liability of Dr Kam arises from the enquiry and conclusion under s 5D(1)(b).

3. It is thus necessary, first, to say something of the operation of s 5D. The framework within s 5D is the division of the enquiry into "the distinct elements of factual causation and scope of liability ... in line with the recommendations in ... the Ipp Report": Strong v Woolworths Ltd [2012] HCA 5 at [19] (per French CJ, Gummow J, Crennan J and Bell J). See also Adeels Palace Pty Ltd v Moubarak [2009] HCA 48; 239 CLR 420 at 440 [45]. The debt that the authors of the Ipp Report owed to Professor Stapleton that was acknowledged in the Ipp Report reinforces the proposition stated in Strong (above) that the subject of s 5D(1)(a) is a purely factual enquiry and not one in which value judgments are made and into which policy considerations intrude: cf March v Stramare (E & MH) Pty Ltd [1991] HCA 12; 171 CLR 506. That is the burden of much of the scholarship of Professor Stapleton in this area. That conclusion is also, and principally, derived from the words of the statute, by the two words in parentheses: "(factual causation)".

4. Thus, the task involved in s 5D(1)(a) is the elucidation of the factual connection between the negligence (the relevant breach of the relevant duty) and the occurrence of the particular harm. That task should not incorporate policy or value judgments, whether referred to as "proximate cause" or whether dictated by a rule that the factual enquiry should be limited by the relationship between the scope of the risk and what occurred. Such considerations naturally fall within the scope of liability analysis in s 5D(1)(b), if s 5D(1)(a) is satisfied, or in s 5D(2), if it is not.

5. Of course, the factual enquiry in s 5D(1)(a) is governed by the nature and content of the duty and its breach since that is the "negligence" referred to in s 5D(1). It is the connection between that and the harm that is to be analysed, factually.

6. The duty is that described by Mason CJ, Brennan J, Dawson J, Toohey J and McHugh J in Rogers v Whitaker [1992] HCA 58; 175 CLR 479 at 483:

   "to exercise reasonable care and skill in the provision of professional advice and treatment ... [being] a 'single comprehensive duty covering all the ways in which a doctor is called upon to exercise his skill and judgment'; it extends to the examination, diagnosis and treatment of the patient and the provision of information in the appropriate case. It is of course necessary to give content to the duty in the given case."

   (Citations omitted.)

   See also at 489:

   "Acceptance of this approach does not entail an artificial division or itemization of specific, individual duties, carved out of the overall duty of care. The duty of a medical practitioner to exercise reasonable care and skill in the provision of advice and treatment is a single comprehensive duty."

7. If a medical procedure has material risks (being risks to which in the circumstances a reasonable person in the patient's position would be likely, if warned, to attach significance or to which the patient would be likely, if warned, to attach significance if the medical practitioner is or should reasonably be aware of that fact) that are inherent, then, leaving to one side the exigencies of emergency or other questions of therapeutic judgment, the scope and content of the duty of care includes a duty to warn the patient of those material inherent risks: Rogers v Whitaker at 487-490, in particular at 490.

8. Whether any set of circumstances where there has been said to be a failure to disclose and appropriately warn of more than one risk may be better viewed as several distinct breaches of the same duty or one interconnected failure to disclose all relevant inherent risks will depend upon a factual enquiry. Here, one operation was being contemplated. The potential benefits and risks of undergoing that operation were all part of the relevant information, as a whole, which the appellant was entitled to have in order to make up his mind, after weighing all relevant information, as to whether to seek the benefits of the procedure, by hazarding such risks as it entailed. It is unrealistic to posit a coherent factual enquiry for the purposes of s 5D(1)(a) by only asking what would have been his decision had he only been told part of what he should have been told. The duty was one comprehensive duty. If it was breached, that occurred, on the appellant's case, by failing to tell him of both possible risks - neurapraxia and paralysis in an appropriately framed and coherent warning that would have enabled him to weigh the benefits and the hazards of the procedure. There are at least two further reasons not to limit the enquiry under s 5D(1)(a) in this way: first, the words of the paragraph and its content do not call for a partial factual enquiry or a factual enquiry truncated by a policy based reason; and secondly, such a truncation may well be factually incoherent. The relationship of the different risks to each other may be close or it may be distant. That may depend upon a number of matters, including the medical relationship of the risks or the attitude or background of the patient.

9. The correct course is to undertake the whole factual enquiry called for by s 5D(1)(a) in order to determine the factual relevance and connection of the negligence to the harm caused.

10. One then turns to the operation of s 5D(1)(b) to assess whether it was "appropriate for the scope of the negligent person's liability to extend to the harm so caused". It is that enquiry which will draw in (without intending to be exhaustive) value judgments, an assessment of the scope of the risks, the type of breaches and risks involved, their relationship to the risk that came home and legal policy questions as to how widely to permit the scope of liability to reach.

11. Strictly speaking, neither enquiry under s 5D(1)(a) or (b) has been undertaken. Factual matters were not found by the primary judge that bear principally upon the enquiry under s 5D(1)(a). For present purposes, those factual matters were what Dr Kam said and what Mr Wallace would have done had full and adequate disclosure been made. These involve assessment of credit and of the witnesses generally. It is not possible for this Court to undertake that factual enquiry. It is only possible for this Court to finalise the matter by assuming that Mr Wallace was not warned of the risk of catastrophic paralysis and if so warned he would not have undergone the operation, and by coming to a view about the operation of s 5D(1)(b) on the facts as they stand.

12. The enquiry and conclusion under s 5D(1)(b) involve a value judgment. In circumstances where s 5D(1)(a) has been satisfied, for the enquiry under (1)(b) to produce an answer that the scope of the liability of the medical practitioner in Dr Kam's position should not extend to the harm that would not have occurred had he or she not been negligent, it is necessary that there be a conclusion either of the tenuousness of the factual link or some limitation by reference to the rule of responsibility involved. For instance, in Chappel v Hart [1998] HCA 55; 195 CLR 232 at 257 [66] and Rosenberg v Percival [2001] HCA 18; 205 CLR 434 at 460 [83], Gummow J gave the example of harm being caused by the misapplication of an anaesthetic in an operation that would not have taken place had the doctor disclosed some inherent medical risk. His Honour characterised the sheeting home of liability as (Chappel at 257 [66]) an "absurd" or "unjust" or (Rosenberg at 460 [83]) an "unacceptable" result that would prevent the law concluding that the negligence caused the harm. This analysis was, of course, at common law under the approach dictated by March v Stramare in which value judgments form part of the process of reasoning about causation. The same kinds of value judgments attend the operation of s 5D(1)(b) (and s 5D(4)), as well as, in another context, s 5D(2). The drawing of a conclusion that a consequence of posited liability would be "unjust", "absurd" or "unacceptable" would be relevant to the conclusion of appropriateness for s 5D(1)(b). Thus, to use the language of the statute, one might restate the point made by Gummow J in his Honour's example by asking whether it is appropriate to extend liability to the defendant where his or her negligence only placed the plaintiff in the place at the time permitting a risk unrelated to that involved in the duty that was breached to come home. If the ceiling of the operating theatre falls in, if the surgeon collapses and strikes the patient, if the anaesthetist misapplies the anaesthetic, if any of countless other things, foreseeable or unforeseeable, go wrong with an operation, a value judgment, based on the rule of responsibility concerned (Environment Agency v Empress Car Co (Abertillery) Ltd [1998] UKHL 5; [1999] 2 AC 22) will have to be made, under s 5D(1)(b). It is in this enquiry that the relationship between the content of the duty (the rule of responsibility), the nature of the risk the subject of the duty and what harm occurred is important: March v Stramare at 516; Faulkner v Keffalinos (1970) 45 ALJR 80 at 86; H L A Hart and T Honoré Causation in the Law (Oxford, 2nd Ed, 1985) at 122.

1. At common law, the ascription of a causal character to a factor without which the harm would not occur, rather than of a non-causal character as a mere condition placing the plaintiff at the place of the harm, depends ultimately on a value judgment (that may well be contestable) made by reference to such (overlapping and at times synonymous) factors as the rule of responsibility and the legal policy underlying it, the content and scope of the duty, the risk addressed by the rule and the duty, the character of the breach, the foreseeability or remoteness of the harm, the intervention of other factors (human and non-human) and their nature, and evaluative common sense. Such considerations also find their place in the enquiry in s 5D(1)(b). Causation is part of the legal analysis concerning whether to attribute legal responsibility and award compensation in a just and coherent way conformable with the legal rule at hand.

2. Here, unlike in the above examples, the harm was factually caused (under s 5D(1)(a)) by the manifestation of an inherent risk that was related to the duty that was breached. The harm here did not occur by the acts or omissions of a third party, or by misapplied anaesthetic, or by some random act or circumstance of the day distinct from the duty to warn. One of the risks, of a number of which Mr Wallace should have been warned, came home. Mr Wallace was in one sense entitled to make his decision on the basis of complete information. That said, the approach to the enquiry under s 5D(1)(b) should reflect the underlying legal aims of the duty and the rule of responsibility: that is, to protect the patient by holding the doctor responsible for the harm that may result from material inherent risks that were not the subject of warning. The duty and the rule of responsibility are not to protect the patient from the risk of an uninformed decision; they are not to protect the integrity of the decision: Rosenberg at 456 [61] and Rogers v Whitaker at 489-490. They are to protect the patient from harm from material inherent risks that are unacceptable to him or her.

3. In the value judgment necessary for s 5D(1)(b), one can readily contemplate circumstances where it was not appropriate to extend the scope of liability, even though a but for test was satisfied. Recovery for the costs of, and inconvenience involved in, an entirely successful operation, in which none of the inherent risks that should have been the subject of a warning came home, might be one. The conclusions that sheeting home such liability would be absurd, unjust, unacceptable or inappropriate would be readily understandable. That conclusion also brings with it the proposition that it is necessary that a risk not warned against come home for there to be an appropriate causal relationship between the breach and the harm. This is the proposition that lies at the heart of the American cases discussed by Beazley JA and referred to below.

4. Another example is that of an inherent risk being clearly disclosed and expressly accepted by the patient, who was content to hazard that risk; that very risk comes home; but the operation would not have been undergone had a quite different risk been disclosed. The factual causal (but for) link may be clear; so, it might be thought, is the injustice or opportunism of the claim. If it is correct to say that injustice and opportunism are suggested by those facts, one is driven to ask what is different about the case here: where the risk that came home was not disclosed, but would, if alone disclosed, have been accepted.

5. In both examples in the previous paragraph, the hazarding of the risk was acceptable to the patient. Unless the further disclosure or disclosures required is or are such that it or they bears or bear on the acceptability of that risk, one would assume that that risk remained acceptable. What was not acceptable was the combination of all the risks such that the procedure became unacceptable. An example of the further disclosure bearing on the acceptability of a risk might be as follows. If the occurrence of neurapraxia was disclosed that risk may have been acceptable in itself with its usual consequences; but if neurapraxia could, in some cases, trigger other catastrophic neurological consequences it would be impossible to say that the risk of neurapraxia had been accepted, even though only the "usual" consequences and discomfortures of it had manifested themselves. But, if neurapraxia was an acceptable risk or hazard, but other risks quite unrelated to it were not, the claim would still be for damage from harm (neurapraxia) the risk of which was acceptable.

6. Of course, these questions are intensely factual involving the relationship between the risks, what risks were acceptable and what were not - whether severally or in combination. Thus, it might not be possible to disentangle one risk from another, in which case the fact that one risk came home would not entitle a conclusion that it should be examined severally. If, however, the risks can be seen as separate and distinct, that is one not bearing on the likelihood of the other occurring, or having no other relevant medical relationship or connection or no known relevant connection for the patient, the policy reasons behind the approach of Gummow J being transferred to the enquiry under s 5D(1)(b) are powerful. By this approach, recovery is limited to risks coming home that were material and that should have been disclosed, and that were not acceptable, in the sense that the patient would not have been willing to hazard that risk for the benefits of the procedure.

7. It is undoubted that the duty is a single comprehensive duty, but the harm for which the doctor should be held liable is the just and appropriate consequences of his or her breach of failing to warn of inherent risks. That, however, 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. This limits recovery to what was an unacceptable risk (or risks) and harm therefrom that has (or have) not been the subject of a warning.

8. Here, the relevant findings of the primary judge at [91]-[94] were clear:

   "[91] In my opinion the plaintiff would not have declined the surgery if warned of the possibility of this condition in general or specific terms as a risk of the surgery he was contemplating. This is so in my opinion whether the risk is characterised as a risk of bilateral femoral neurapraxia, local nerve damage, weakness in either or both of his legs or in general terms that he could be left temporarily worse off with a condition fitting these descriptions. This is for the following reasons.

   [92] As the result of his preoperative condition, as described by him, the plaintiff was desperate for some form of pain relief. He had attended a pain management centre in an effort to try to reduce the pain in his back and legs. He agreed he had had some difficulty attempting to do this. He had tried physiotherapy but this had not helped. He was taking more and more medication with no corresponding benefit. He could only walk with the aid of a walking stick. No conservative measures had worked. Dr New had foreshadowed the need for surgery. The plaintiff was 'absolutely fed up with having to take medication'. He was in a perpetual (medicated) daze. He told Dr New that the fact of the matter was that he was not getting any better. He felt inadequate and useless. He had severe restrictions in movement. This was a cause of significant stress and anxiety. He had bouts of depression because his future was uncertain. He approached Dr Kam for assistance to try to do something about unremitting pain, because he could barely move. Dr Diwan had told him that surgery might be risky. He agreed Dr Kam had told him the same thing. By the time he saw Dr Kam for the second time 'he was desperate for relief'. He could hardly walk. He had tried everything and nothing had worked. He had even had suicidal thoughts. To the suggestion that he was in desperate straits, he agreed he was in a lot of pain. The last resort was to undergo surgery.

   [93] A key to understanding what the plaintiff would have done if warned of the risk that in fact materialised is to compare the plaintiff's condition before the operation with the effects of the bilateral femoral neurapraxia itself. There is in my opinion no comparison at all. In a report dated 26 November 2004 addressed to Dr Kam, Dr Awad referred to the bilateral femoral neurapraxia and indicated that the plaintiff's 'power in his legs is slowly improving and he has some anti-gravity movements and he has been slowly mobilised with the physiotherapists'. As earlier recorded, Dr Dowla found that by 25 February 2005 the objective neurophysiological evidence did not support the existence of any definite neuropathic abnormality.

   [94] In my opinion, having regard to his desperate preoperative plight, the plaintiff would not have declined the proposed surgery upon the basis of a possible risk of the condition that he suffered in fact. The prospect for this plaintiff of some mild and temporary interference with power and sensation in his lower limbs is out of all proportion to the disabling and distressing condition from which he hoped Dr Kam's surgery would provide a cure or at least some relief. It is to my mind inconceivable, or at the very least highly unlikely, that the plaintiff would have hesitated for a moment to submit to a procedure which he knew to be attended by all of the risks Dr Kam said he informed him of, as well as the risks of which on my finding he should have been informed, in circumstances in which he was in a desperate search for relief from unremitting pain, when there was a 70 to 75 per cent chance of some relief and when the relevant cost to him may have been a mere temporary loss of power and sensation in his lower limbs of the nature, extent and duration of the condition that materialised."

   These findings were to the effect that that the risk of neurapraxia was acceptable to Mr Wallace. That risk came home.

9. There was no suggestion that the neurapraxia was medically related to the risk of catastrophic paralysis. On the material, they can be taken to be distinct risks, albeit part of the various matters that should have been disclosed to Mr Wallace in one body of disclosure.

10. I will assume for the purpose of seeking to resolve the appeal that Mr Wallace would not have undergone the operation had he been warned of the 5 per cent risk of catastrophe and that Dr Kam did not disclose this risk. That is to say, however, on the material, that he would not have undergone the operation knowing of the additional and distinct risk of the catastrophic paralysis.

11. The expression of the matter by Gummow J in Rosenberg at 461 [86], though in the context of a single risk, supports the conclusion that extending Dr Kam's liability through the enquiry under s 5D(1)(b) would not be appropriate. To paraphrase what Gummow J said in Rosenberg, it will be appropriate for the scope of liability to extend to circumstances where the doctor fails to warn the patient of a particular consequence and that consequence (reflecting a material risk) in fact eventuates. The rule of responsibility seeks to hold the doctor liable for the consequence of material risks that were not warned of that were unacceptable to the patient.

12. This approach has the support of the United States cases to which Beazley JA refers. The requirement that the undisclosed risk come home in an overwhelming number of jurisdictions (see the citations in Cochran v Wyeth Inc 3 A 3d 673 at 680 (2010)) reflects the widespread acceptance of a qualification of the but for test conformable with notions of legal causation reflected in the use of the phrase "proximate cause". This use of the expression "proximate cause" in this context can be seen to involve the employment of a limiting factor based on legal policy considerations drawn from a value judgment of the kind that falls to be made within s 5D(1)(b), by reference to the content of the duty.

13. It is to be recognised here, however, that the risk that came home, neurapraxia, was undisclosed. If this is where one left the analysis, the words of Circuit Judge Robinson speaking for the Court of Appeals for the District of Columbia in Canterbury v Spence 464 F 2d 772 at 791 [32] (1972) (though necessary to transpose into a situation of multiple risks to be disclosed) might appear to support the appellant's argument, albeit in the context of objective rather than subjective causal analysis:

    "If adequate disclosure could reasonably be expected to have caused that person to decline the treatment because of the revelation of the kind of risk or danger that resulted in harm, causation is shown, but otherwise not."

14. One must, however, recognise the importance of the phrase "because of the revelation of the ... risk or danger". The Court in Canterbury v Spence was emphasising the relationship between disclosure and manifestation of the risk. The further relevant fact here is that the primary judge found, with some clarity, that this risk, although undisclosed, was acceptable to Mr Wallace in that it, as a risk distinct from the catastrophic paraplegia, would not have led Mr Wallace to decline the operation. It is the value judgment to be made consequential on that finding that is critical. That value judgment, in the circumstances here where the risks are distinct, in my view, is one that is indistinguishable from that to be made consequent upon disclosure and acceptance of the risk that came home.

15. Further, it is important to understand how the appellant ran his case below. The primary judge described this in [95] of his reasons, as follows:

    "Although, as I have found, the plaintiff would have undergone the surgery even if warned of bilateral femoral neurapraxia or local nerve damage, the plaintiff contended that if he was entitled to be, but was not, warned of some risk that would have led him to decline the surgery, he is legally entitled to complain about the consequences of any risk that eventuates, even if that specific risk would not by itself have led him to do so. In this case that translated to a proposition that if the plaintiff would have declined the surgery if warned of some catastrophic outcome of which he was not warned, but which did not materialise, but would not have declined the surgery if warned of bilateral femoral neurapraxia, which did materialise, he is entitled to succeed because the latter condition was caused by the very fact of an operation he would have declined if properly warned."

16. This is also how the matter was in substance put on appeal. This makes clearer the legitimacy of equiparating the value judgments based on actual disclosure and acceptance, on the one hand, and non-disclosure, but a clear finding of acceptability, on the other. Of importance to that equiparation is the separateness and distinctiveness of the risks, which the argument of the appellant below and in this Court implicitly recognised.

17. If I may say so, the passage of Lord Caplan in Moyes v Lothian Health Board 1990 SLT 444 at 447 set out by Beazley JA has a degree of persuasion. Ultimately, however, I am not persuaded that liability for the consequences of multiple inherent risks should not be limited by reference to the considerations suggested by Gummow J and the American cases.

18. In any given case, the facts will need to be examined in a complete enquiry under both (1)(a) and (b) in order that the relationship, if any, between the individual risks be understood. If one risk, being part of a body of risks about all of which there should have been warning, comes home it may be viewed, depending on the precise facts, in particular the medical connection between the risks or the importance of the relationship of the risks to the patient, as not merely the manifestation of that individual risk, but as part of a whole body of inter-related and inter-connected risks that should not be separately examined or analysed. Nor should the examination of the risks disclosed and what risk comes home be examined over-finely. These are medical questions, set in a context of the human and professional activity of warning of risks, the analysis of which is unlikely to be assisted by over refinement.

19. Here, while the primary judge has not undertaken the enquiry expressly under s 5D(1)(b), his approach was in significant respects a substantial enunciation of its elements. I do not see from the material how the risk of neurapraxia and the 5 per cent risk of catastrophic paralysis can be seen other than as distinct matters for disclosure, albeit in the one body of disclosure. The two risks were not said to be related in any particular way. The fundamental argument put by the appellant below and in this Court implicitly recognised this distinction. The finding of the acceptability of the distinct risk that came home was clear and unequivocal in [91]-[94] of the primary judge's reasons. In these circumstances, even making the assumptions that I have, it would not be appropriate to extend to Dr Kam liability for the harm that occurred, and there is no purpose in remitting the matter to the primary judge for further hearing or consideration.

20. Looking at the matter thus, the appeal should be dismissed.

21. Notwithstanding the difficult issues raised, prima facie that dismissal should be followed by an order for costs. If any application is to be made to vary that it should be in the form of a notice of motion supported by submissions and any evidence, filed within 14 days.

22. The orders that I would make are that the appeal be dismissed with costs.

23. BEAZLEY JA: On 22 November 2004, the appellant underwent a six-hour L4/L5 posterior lumbar interbody fusion and pedicle screw fixation (the surgery), performed by the respondent, a neurosurgeon, at Westmead Private Hospital. A further surgical procedure was performed the following morning as a result of the appellant experiencing extreme pain and paralysis in both legs upon regaining consciousness after the surgery. The appellant's difficulties persisted after the further surgical procedure and he was subsequently diagnosed as having suffered bilateral femoral neurapraxia, that is, local nerve damage to the anterior femoral or thigh region of both legs, caused by lying prone for an extended period during the surgery.

24. The appellant commenced proceedings against the respondent claiming damages for breach of duty in failing to warn him of the material risks of the operation. The appellant contended there were two material risks of the operation that the respondent did not disclose to him. The first was the risk of local nerve damage to the thigh, that is, bilateral femoral neurapraxia, as the appellant lay face down on the operating table for an extended period during the surgery. That risk came home. The second risk was a 5 per cent risk of paralysis. That risk arose because the site of the operation was in the spinal cord and there was an inherent risk of injury to the spinal nerves during the course of the operation causing paralysis. This risk was described during argument as a risk of a catastrophic outcome.

25. The trial judge, Harrison J, held that the respondent had breached his duty of care to the appellant in failing to warn of the risk of bilateral femoral neurapraxia. However, as his Honour was not satisfied that the appellant would have declined the surgery had he been warned of that risk, he held that the appellant had failed to establish any causal connection between the respondent's breach of duty and his injury. It followed that the appellant had not proved his cause of action and his claim failed. A verdict was entered for the respondent.

26. The appellant has appealed from the verdict and seeks judgment in his favour in the sum of $350,000, being the amount of damages agreed between the parties at trial in the event the appellant was successful on his claim.

1. The essential issue raised on the appeal was whether the appellant's injury of bilateral femoral neurapraxia was caused by the respondent's breach of duty. On the appellant's argument, the relevant duty was to warn of material risks associated with the surgery and that the respondent breached that duty in failing to warn of the risks of neurapraxia and paralysis. He contended that had he been warned of both risks, and in particular the risk of a catastrophic outcome of paralysis, he would not have undergone the surgery. It followed on this argument that the respondent's breach in failing to warn of the risks of the operation caused the harm that he suffered and he was entitled to succeed on his claim.

Background facts

1. The appellant, who was 57 years of age at the time he underwent the surgery, suffered from a back condition as a result of carrying heavy equipment in the course of his employment. His back condition worsened towards the end of 2003 and this carried over into 2004. He sought medical treatment and underwent a number of investigations and procedures and was diagnosed with an intervertebral disc protrusion in his lumbar spine.

2. The appellant first consulted the respondent in 2004. At that time, he weighed approximately 124 kg and described himself as being "desperate for some relief as [he] could hardly walk". Following the respondent's recommendation that if he lost weight he might obtain some relief, he went on a crash diet and his weight dropped to about 110 kg over approximately three months. However, his back pain did not ease. It also appears that the appellant either regained weight or his estimation of his weight loss was inaccurate as, at the time of surgery, his weight was between 118 kg and 122 kg.

3. At a consultation on 5 October 2004, the respondent recommended immediate surgery. On this occasion the respondent told the appellant that if he did not have surgery, he would end up in a wheelchair, become incontinent and lose control of his bowels. The appellant said that this "really scared the hell out of me" and as he was in so much pain, he agreed to surgery.

4. Following the surgery on 22 November 2004 and the second operation on 23 November 2004, the appellant was hospitalised until 16 February 2005, initially at Westmead Private Hospital and then at St Joseph's Hospital, Auburn. The appellant continued to be significantly disabled after his discharge and at trial his case was that he was an incomplete paraplegic.

The trial judge's reasons

1. The trial judge identified the following issues for determination: (1) whether the respondent breached his duty of care to the appellant by failing to give a proper warning of the risks of the surgery he performed (the breach issue); (2) whether the appellant suffered harm in the circumstances (the injury issue); and (3) if harm was suffered, whether that harm was caused by the respondent's negligence (the causation issue).

2. His Honour found that the appellant sustained bilateral femoral neurapraxia following the surgery on 22 November 2004 and that the further surgical procedure carried out on 23 November 2004 was a consequence of the surgery on 22 November 2004. There is no issue about these findings on the appeal and thus the injury issue can be put to one side.

3. As to breach, the respondent conceded that he had not warned the appellant of the risk of bilateral femoral neurapraxia and that he should have done so. The trial judge found that this risk was an inherent risk of the surgery and was significant in this case because of the appellant's weight. In this regard, the appellant's weight increased both the likelihood of the occurrence of the condition as well as the extent and degree to which it might affect him if it occurred. His Honour held, at [49], that the risk of bilateral femoral neurapraxia was material.

4. Flowing from the respondent's concession as to the need for and his failure to give a warning of bilateral femoral neurapraxia, and his Honour's finding that the risk was material, his Honour held, at [51], that the respondent breached his duty of care to the appellant in failing to warn him of that risk and/or its associated symptoms or consequences. Importantly for the issue on the appeal, his Honour held, at [96], that the failure to warn of bilateral femoral neurapraxia was the only potentially relevant failure to warn.

5. His Honour concluded that if the respondent had warned of this risk, the appellant would nevertheless have undergone the surgery. Hence, the appellant had not satisfied the first limb of the test of causation in the Civil Liability Act 2002, s 5D(1)(a).

6. His Honour made no finding as to whether the respondent had failed to warn the appellant of the 5 per cent risk of paralysis or whether such risk was material. His Honour found that the appellant's allegation that the respondent had failed to warn him of possible catastrophic consequences associated with known risks of the surgery was not relevant, because that risk had not come home. His Honour cited Rosenberg v Percival [2001] HCA 18; 205 CLR 434 in support of this conclusion.

7. Apart from the conceded failure to warn of the risk of bilateral femoral neurapraxia, there was a dispute between the parties regarding what the respondent told the appellant as to the risks of the surgical procedure.

8. The appellant's evidence in chief was that the respondent told him there was a 75 per cent chance of the surgery being successful and did not mention anything that could go wrong, leaving him with the impression that if the surgery was unsuccessful he would simply be the way he was before the surgery. In cross-examination, the appellant said the advice was of a 70-75 per cent chance of the operation being successful. He said he believed there were no negative aspects to the surgery. He reiterated his understanding from what the respondent told him, that the worst that could happen was that he would simply be the way he was before the operation. The appellant also said that the respondent told him that if the operation was successful he would be in no pain at all and would be able to stop taking medication which, prior to surgery, had quadrupled in quantity and strength from when it was first prescribed.

9. The appellant agreed in cross-examination that the respondent specifically told him that any surgery had risks and complications. He also said he understood spinal surgery was "a serious business". He did not recall that the respondent specifically told him there was a risk of injury to his nerve roots and denied that he was told he could be left with weakness in either or both legs. He also denied he was told that he could have spinal cord injury, which could affect either or both of his legs, or that he could develop bladder and bowel incontinence as a result of the surgery. These denials were emphatic. In a later part of the cross-examination, the appellant said he could not remember the bladder and bowel being discussed. All he remembered was that the respondent said if he did not have surgery he would be incontinent. He also denied he was told the surgery could take longer because of his weight.

10. The appellant's wife, who had accompanied the appellant on his consultations with the respondent, also gave evidence. She agreed in cross-examination that the respondent told the appellant that even though he had not lost enough weight, consideration needed to be given to proceeding with the surgery. She agreed the respondent said that any surgery was accompanied by risks and complications and there were no guarantees. She also agreed in cross-examination that the respondent told the appellant there was a risk of nerve root injury. However, she could not remember the respondent saying the appellant could be left with weakness in either or both of his legs after surgery. Nor did she remember if anything was said as to the risk of injury to the spinal cord.

11. The respondent's evidence was that from the time of the first consultation he was concerned with the appellant's weight. His initial recommendation was for the appellant to attempt a significant weight loss program, with surgery as a last resort. The respondent said his advice to the appellant was that if there was no improvement in the appellant's level of pain after the weight loss, he may be a candidate for surgery.

12. The last consultation prior to surgery was on 5 October 2004. At that time, the appellant described his condition as being "really bad. He said that he had not been able to leave the house or get out of bed to go to the kitchen. The respondent observed that the appellant had put on weight. The respondent said that at this time, given the appellant's condition, he again advised that consideration should be given to surgery notwithstanding that the appellant had not lost enough weight.

13. The appellant's wife gave evidence that the respondent told the appellant he had no choice, he had to have surgery and if he did not, he would become incontinent. She said the respondent told the appellant he would be better off with the surgery and that otherwise he would be in a wheelchair, going to the toilet on the chair, and he would have no quality of life.

14. The respondent's evidence was that, having regard to his usual practice when discussing the risks and providing warnings in relation to a proposed fusion and pedicle screw fixation on an obese patient, he would have informed the appellant of the following matters: any surgery was accompanied by potential risks and complications; there were no guarantees with the surgery; there was a risk the appellant could sustain nerve root injury, which could leave him with a weakness in either or both legs; there was a risk of spinal cord injury, which could affect both legs; and there was a risk that he could develop bladder and bowel incontinence after the surgery.

15. The respondent also said he would have advised the appellant that due to his weight and size, the operation would take longer and his recovery would be prolonged. He said that he would have informed the appellant that even if the surgery was uneventful there was a chance that the back pain would not be resolved and would be ongoing. He said he would have informed the appellant that in his case he would estimate the probability of a successful outcome, being a significant decrease in pain, to be about 70 per cent.

16. The respondent stated in his oral evidence that his usual practice was to give a warning that there was roughly a 5 per cent chance of a catastrophic outcome of nerve root injury. No mention had been made of this in his witness statement. The respondent explained this omission as an error. When challenged in cross-examination that he had never informed the appellant of the 5 per cent risk of a catastrophic outcome, the respondent disagreed. He also disagreed that he was telling an untruth in respect of this aspect of his evidence. The respondent agreed in cross-examination that his reference to a 70 per cent likelihood of a successful outcome was not a suggestion that there was a 30 per cent chance of a catastrophic outcome. Rather, he was suggesting there was a 30 per cent chance the appellant's condition would remain the same.

17. The trial judge did not determine the factual dispute between the appellant and the respondent as to whether the respondent informed the appellant of the risk of a 5 per cent catastrophic outcome. He did, however, make observations as to the credit of the appellant, the appellant's wife and the respondent. As to the appellant, his Honour observed that he gave his evidence clearly and apparently truthfully and noted that, in any event, there was no attack upon his credit. His Honour also noted that there was no challenge to the truthfulness of the appellant's wife.

18. However, there had been an attack on the respondent's credit, in that he was challenged as to his version of what he told or at least what, in accordance with his usual practice, he would have told the appellant in relation to the risk of a catastrophic outcome. His Honour commented that the respondent's concession that he had not given a warning about the risk of bilateral femoral neurapraxia or local nerve damage cast the balance of the respondent's evidence in a favourable light. His Honour said, however, that to the extent it was necessary to do so, he found the respondent did not warn the appellant of the risk he could be left with weakness in either or both legs.

Arguments on the appeal

1. The appellant's principal contention on the appeal was that his Honour erred in confining the relevant breach of duty to the failure to warn of the risk of bilateral femoral neurapraxia. The appellant contended that the scope and content of the respondent's duty was to adequately warn the appellant of material risks of the operation, that duty being a "single, comprehensive duty": see Rogers v Whitaker [1992] HCA 58; 175 CLR 479.

2. The appellant submitted that his Honour misapplied Rosenberg v Percival in finding that a failure to warn was not relevantly causative of harm unless the risk in respect of which there was inadequate warning, materialised. His Honour's consequent finding on causation was thereby erroneous. Alternatively, the appellant contended that Rosenberg v Percival ought to have been distinguished by his Honour on the basis that it involved a case where there was only one material risk, not two as was the case here.

3. The appellant contended the respondent had breached his duty of care not only by failing to warn of the risk of bilateral femoral neurapraxia, but also in failing to warn of the 5 per cent risk of a catastrophic outcome. It followed that given the "single, comprehensive" nature of the duty to disclose the material risks inherent in the operation and, on the assumption that there had been a breach of that "single, comprehensive duty", the causation issue had to be determined having regard to the entire breach.

4. The appellant submitted that the correct question for his Honour's determination on the causation issue was whether the appellant would have refused surgery on 22 November 2004 had he been warned, not only of the risk of bilateral femoral neurapraxia, but also of the 5 per cent risk of a catastrophic outcome. The appellant contended that the answer to that question should have been that he would have deferred or refused surgery at that time.

5. The respondent submitted that his Honour correctly determined causation as a matter of principle and as a question of fact. He contended that even if it were to be found that he had not warned of the risk of a catastrophic outcome, it was not appropriate for the scope of his liability to extend to that failure, when that risk had not eventuated.

6. The trial judge did not determine whether the risk of a 5 per cent chance of a catastrophic outcome was material or whether the appellant was warned of that risk. Both involve factual determinations of a different order. The question of materiality is determined objectively in the circumstances of the particular case: see Rogers v Whitaker at 490 (Mason CJ, Brennan, Dawson, Toohey and McHugh JJ); Rosenberg v Percival per Gummow J at 455. A reasonable person, contemplating operative treatment to resolve a condition that was not life threatening and potentially not urgent, may well attach significance to a 5 per cent risk of a catastrophic outcome in making a decision as to whether or not to undergo surgery and the respondent did not suggest to the contrary. It may be that there is no real issue as to the materiality of the risk. However, it is a question of fact for the determination of the trial judge.

7. What the appellant would have done if warned of the risk of paralysis involves a subjective determination in accordance with s 5D(3). Both parties submitted that this Court could determine this question. In doing so, neither party directed attention to the necessity to first determine whether the risk was material. Assuming materiality of the risk, the appellant advanced a number of factual circumstances that he submitted would lead a fact finder to conclude that he would not have had the operation. These matters included: his weight being more than he believed and the respondent not having informed him of his correct weight; the scope for more weight loss before surgery was finally decided upon; the fact that the appellant was under a misapprehension that the back surgery was necessary at that time; that the surgery was not urgent and the respondent's reason for recommending it at that time was the appellant's loss of quality of life, given his failure to lose weight. The appellant also contended that the trial judge overstated the appellant's future mobility restrictions in finding that he would have been housebound and bedridden for many weeks had the surgery not been undertaken at that time.

8. The respondent for his part contended that on the evidence, the Court would find that that the appellant would have had the operation in any event. The respondent referred to the appellant's condition in the weeks immediately preceding the last consultation when he was significantly incapacitated and effectively bedridden due to pain from his condition.

The legal principles

The statute

1. As this case fell to be determined in accordance with the provisions of the Civil Liability Act, the question of causation had to be determined on the basis of the provisions of s 5D. That section provides, relevantly:

   "5D General principles

   (1) A determination that negligence caused particular harm comprises the following elements:
   (a) that the negligence was a necessary condition of the occurrence of the harm (factual causation), and
   (b) that it is appropriate for the scope of the negligent person's liability to extend to the harm so caused (scope of liability).

   (2) In determining in an exceptional case, in accordance with established principles, whether negligence that cannot be established as a necessary condition of the occurrence of harm should be accepted as establishing factual causation, the court is to consider (amongst other relevant things) whether or not and why responsibility for the harm should be imposed on the negligent party.

   (3) If it is relevant to the determination of factual causation to determine what the person who suffered harm would have done if the negligent person had not been negligent:
   (a) the matter is to be determined subjectively in the light of all relevant circumstances, subject to paragraph (b), and
   (b) any statement made by the person after suffering the harm about what he or she would have done is inadmissible except to the extent (if any) that the statement is against his or her interest.

   (4) For the purpose of determining the scope of liability, the court is to consider (amongst other relevant things) whether or not and why responsibility for the harm should be imposed on the negligent party."

2. Reference should also be made to s 5E, which provides:

   "5E Onus of proof

   In determining liability for negligence, the plaintiff always bears the onus of proving, on the balance of probabilities, any fact relevant to the issue of causation."

3. Division 6, s 5O, which makes provision for the standard of care for professionals has no application to cases involving failure to warn: see s 5P, and thus is not relevant to the problem with which the Court is presently concerned.

4. The appellant submitted that in this case s 5D(1)(a), that is, the "but for" test, was satisfied: the respondent's breach of the duty to give him an adequate warning of the material risks of the operation was a necessary condition of the harm he suffered. He also submitted that s 5D(1)(b) was satisfied as it was appropriate for the scope of the respondent's liability to extend to the harm so caused.

5. Section 5D is relatively recent legislation and there is at this point little High Court authority as to its scope and application and there is no authority on the application of s 5D in a case such as the present. There also appears to be scant consideration in the case law generally of the particular issue of causation that arises here.

1. Gummow J noted, in relation to "the second level", that a failure to warn of a risk cannot be said to "cause" an injury in the same way that one speaks of causation in respect of careless conduct in carrying out the operation. The second level requires identification of the purpose for which a causal relationship is being assessed, namely the attribution of responsibility for the harm. At [86], he continued:

   "[The relevant rule] imposes an obligation upon medical practitioners adequately to warn their patients of the consequences of the treatment they are contemplating. If the medical practitioner should fail to warn the patient of a particular consequence and that consequence in fact eventuates then, subject to the question of materiality, the rule seeks to hold the medical practitioner liable for that consequence."

2. The reference to warning of "a particular consequence", followed by the condition that "that consequence in fact eventuates" is not ambiguous. Nor is it to be dismissed as an incautious or inaccurate use of language.

3. The US cases referred to by Beazley JA are to similar effect. The results in those cases are not to be ignored because the judges used the language of "proximate cause" not presently in vogue in Australia. That phrase may be traced to Sir Francis Bacon: Michael S Moore, Causation and Responsibility: An Essay in Law, Morals and Metaphysics (OUP, 2010), p 101. It is, like "scope of liability", a label to describe the boundaries of liability derived from the purposes or policies of the law. It does not dictate one conclusion rather than another.

4. The arguments in favour of permitting recovery in this case, subject to relevant facts being found, are broadly twofold. One is that the duty to warn should not be subdivided because the decision to undergo treatment is a single decision made by assessing all the appropriate information: it cannot sensibly be partitioned. A second, though related, argument is that the risks were not entirely distinct, as were the risk of severing a nerve and a problem with anaesthesia, in the example used by Gummow J in Chappel v Hart [1998] HCA 55; 195 CLR 232 at [66] and in Rosenberg at [83].

5. These arguments clearly turn on matters of degree and do not rely on watertight legal categorisation. Thus, in respect of the first argument, there is a close correlation between the tasks of assessing the materiality of a risk and the causal relationship with the harm. Neither can be resolved without careful attention to the particular risk as identified in the medical literature, the manner in which it should be described to the patient and the way in which it will be understood and assessed by the patient. Although the patient has but one decision to make, the factors to be placed into the balance in making that decision (in the somewhat idealised paradigm adopted by the law) are separate and each has its own weight.

6. The correlation between the tasks of assessing the materiality of a risk and the causal relationship with the harm is also close in a practical sense. Absent some subjective element known to (or which should have been apprehended by) the practitioner, "materiality" involves an objective test of assessing the likely significance of a particular risk, but by reference to a reasonable person in the plaintiff's position. The test of causation is said to be subjective, namely, asking whether this patient would have declined to undergo the treatment. However, given the inadmissibility of any statement by the patient after suffering the harm, and favourable to his or her interests, as to what he or she would have had done had the appropriate warning been given (s 5D(3)(b)), the difference between the two tasks is diminished. At least that is so in a case where the plaintiff has exhibited no specific concern before the operation as to the risks involved. Yet the materiality analysis, relevant to the identification of breach, does require separate assessment of each risk as to which it is said a warning should have been given. A trial judge could accept that, although the warning with respect to a specific risk would not have been significant to this patient, objectively it should have been given. Such a conclusion must carry with it a strong implication in relation to the possible causal connection with the harm in fact suffered.

7. In respect of the second argument, it is not self-evident that the two risks in question were closely associated. The catastrophic risk of paralysis was inherent in the site and nature of the procedure, close to the spinal column. It could have a close connection with the skill and care exercised by the surgeon in carrying out the operation. By contrast, the bilateral femoral neurapraxia, which materialised, arose from the fact that the patient was required to lie prone for a significant period. The distinction between the two is not far removed from the examples relied on by Gummow J, being the possible injury to the laryngeal nerve and the risk of misapplication of the anaesthetic.

8. As a matter of principle, if the purpose of requiring payment of compensation is to require the defendant to bear the cost of the harm eventuating from his or her negligent conduct, it is far from clear why that burden should be imposed in circumstances where the harm could only have arisen from breach of another element of the duty. Once the trial judge was not persuaded that a warning as to bilateral femoral neurapraxia would have led to a postponement of the operation, why should the practitioner bear responsibility for breach of a separate duty to warn of a risk which did not materialise? Recovery in such circumstances appears opportunistic.

9. If recovery of compensation were to be accepted in this case, it would be on the basis of the negligent failure to warn of the catastrophic risk, while the injury suffered was the bilateral femoral neurapraxia. The causal relationship would be established by a finding (yet to be made) that, if warned of the potentially catastrophic risk, the appellant would not have undergone the procedure. On that analysis, any harm which resulted from the operation would have been sufficient to attract compensation. Whether the harm which in fact resulted was a risk as to which a warning should have been given would appear not to be a relevant consideration, once it is found that, if a warning as to that risk had been given, the appellant would nevertheless have proceeded with the operation. The same result would follow if the warning had in fact been given and, consistently with the finding of the trial judge, the appellant had proceeded to undergo the operation. However, it is hard to identify a principled basis upon which a practitioner should be made legally responsible to pay compensation to a person who suffered an adverse outcome as to which he or she had been properly advised and had accepted. By contrast, there is a clear justification for imposing liability on a medical practitioner in respect of the harm suffered where an adverse outcome of which a warning should reasonably have been given, but was not, has come to pass. The principle which supports recovery in the latter case cannot, without some significant variation or expansion, justify recovery in the present case.

10. Section 5D does not clearly compel one answer to this question, rather than another. The language of the section involves (inevitably) a level of generality, which does not easily cover the circumstance where the negligence is a failure to warn of risks which inhere in a procedure carried out with due care and skill. Although it may be said that a number of physical conditions were "necessary" for the occurrence of the harm in the present case, the failure to warn of the risk which came to pass was not one. Accordingly, that aspect of the negligence of the respondent did not bear that causal relationship with the outcome sufficient to warrant imposing on him responsibility for that harm. That conclusion is at least consistent with the language of s 5D(1)(a). Alternatively, if the exclusion of something which otherwise qualifies as a necessary condition of the injury depends on a normative judgment, then it is appropriately excluded in the present case, pursuant to s 5D(1)(b) and (4).

11. The general law authority (limited as it is) weighs in favour of the conclusion reached by the trial judge, namely that relevant negligence had not been established.

12. If the weight of general law authority, to be applied pursuant to the statutory scheme, were not against a finding of liability in the present case, it would be necessary to consider whether legal principle warranted an extension of existing authority to cover the case. There are significant reasons for this Court declining such an expansion of the area of liability.

13. As explained by Kirby J in Rosenberg at [143], there is an extensive literature suggesting that the law in respect of this aspect of the patient-practitioner relationship has tended to part company with reality, in the sense that the assumptions upon which the "duty to warn" is based are fictitious or at least exaggerated. There is empirical evidence that many patients do not want and do not know how to cope with the uncertainty created by such warnings. Further, many patients go to a practitioner for skilled advice, not to be given a smorgasbord of considerations they are ill-equipped to assess. (These and related issues are exposed and analysed with clarity by Gerd Gigerenzer in Reckoning with Risk (Penguin, 2002) at pp 100-101.) The law rarely asks whether a warning should be given in a particular form and how it would be understood by the patient. For example, if a practitioner advising a particular procedure says, "the medical literature reveals that this procedure is associated with adverse consequence 'x' at the rate of 1%, but I have done the procedure 1,000 times, with no case of adverse consequences", the patient might infer that this practitioner is particularly expert, or that she is facing a string of adverse outcomes in the near future. Without attention to the precise form, content and context in relation to particular risks, the imposition of legal liability will not further the purposes underpinning the law.

14. In Rosenberg, Kirby J supported the obligation mandated by Rogers on a number of bases at [145]. Whether those considerations would favour an expansion of the current limit of liability is not a matter which can properly be resolved by this Court, but should properly be addressed by the High Court, or the Parliament.

15. The trial judge undertook a careful analysis of the evidence and the law and dismissed as irrelevant the possible failure to warn of the risk of a catastrophic outcome (as to which there was conflicting evidence). He was correct to do so. The appeal should be dismissed with costs.

16. Since writing the above, I have had the opportunity to read the reasons of the President. To the extent to which our reasoning is consistent, I agree with his more expansive analysis of the issues. To the extent we differ, primarily as to whether s 5D demands a rigid separation of physical and policy considerations in assessing causation, I would accept his alternative analysis, if thought to be preferable. It does not affect the result in the present case.

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