Introduction
In its Judgement of 23 December 2016, the Supreme Court expressed itself for the first time on the doctrine of lost chance in a medical liability case. The direct object was a child who, despite treatment by the Erasmus MC, became blind shortly after birth. After more than 13 years of litigation, the parents and the child have come one step closer to receiving their compensation.

The essence of this case is the question whether Erasmus MC is liable for the loss of a chance of a better treatment outcome. On appeal in cassation, an important element was the question whether the Court of Appeal had correctly assessed the claim for (compensation for) lost chance and had included the expert reports in its assessment in an understandable manner.

Factual background
Twins were born in May 1996. One child died in the first week after her birth, the other baby had to undergo abdominal surgery shortly after birth. Due to inadequate blood circulation in her right leg, necrosis occurred and eventually her foot had to be amputated. The hospital treating the child, Erasmus MC, accepted liability for this.

On 25 June 1996, an ophthalmologist examined the child for the presence of ‘retinopathy of the premature’ (ROP), but this examination failed because the pupils were not (no longer) dilated. A second examination took place on 9 July 1996. On the basis of the findings during this examination, the ophthalmologist decided that emergency treatment was required. Both eyes were treated on 10 July 1996, but this has not been able to prevent the child eventually becoming blind.

The parents and the child held Erasmus MC liable.

The claim includes the assertion that the child had lost a better treatment result because the ophthalmological follow-up examination and treatment had not taken place earlier. According to the claimants, prompt treatment was necessary in view of the chance of developing ROP and everything should therefore have been done to have another eye examination as soon as possible.

Both the District Court and the Court of Appeal rejected the claims. Subsequently, a successful appeal to the Supreme Court was lodged, so follows from the judgement of the Supreme Court of 23 December 2016 (ECLI:NL:HR:2016:2987).

Lack of grounds, application of wrong criterion and lost chance
In its judgement of 21 April 2015, the Court of Appeal in The Hague did not to address the assertion of the claimants that a re-examination should have taken place in a shorter term than one week, earlier than on 2 July 1996 therefore.
For this reason, the Supreme Court considers that the Court of Appeal had inadequately substantiated its opinion.

The Court of Appeal had also considered that a (sufficiently) realistic chance of a better treatment result had not been lost because follow-up examination after 25 June 1996 had not taken place earlier than on 9 July 1996.
The Court of Appeal considered that the assessment of the hypothetical situation of the child having been treated earlier, must not be tested against the standard of the optimally acting ophthalmologist but that of the reasonably acting and reasonably competent ophthalmologist. From the expert reports, the Court of Appeal derived that a reasonably acting and reasonably competent ophthalmologist would have set the follow-up examination at a term of one week, in which case treatment would have taken place approximately at the same time and there was therefore not a case of lost chance. The Court of Appeal considered that the fact that there may be some lost chance if one proceeds on the basis of an optimum (earlier) treatment, is not relevant for the assessment of the current claims, in view of the assessment against the aforementioned standard.

This view of the Court of Appeal also did not hold. The Supreme Court formulated the relevant legal rules.

According to the Supreme Court, the Court of Appeal failed to appreciate that in answering the question whether a chance of a better treatment result had been lost for a patient, it must first be assessed whether there have been acts contrary to the standard of that which befits a reasonably acting and reasonably competent professional colleague.
If it is concluded that there have been violations of this standard, then subsequently, in the assessment of the causal link between the violation of the standard and the alleged loss, a comparison must be made between the factual situation after the violation of the standard and the hypothetical situation such as it would have been if the violation of the standard had not occurred. As regards the factual situation, it concerns the determination of that which actually occurred. As regards the hypothetical situation, it concerns the determination of what actually would have happened without the violation of the standard. According to the Supreme Court, this hypothetical situation must therefore not be based on the standard of a reasonably acting and reasonably competent professional colleague but on the treatment that would have actually taken place, be it that the principle must be that no violation of the standard would have occurred.

In this context, a witness statement of the acting ophthalmologist is referred to, who stated that it cannot be denied that the chances of the child would have been better with earlier treatment.

According to the Supreme Court, the Court of Appeal had wrongly not addressed the question what the ophthalmologist would have done if the second attempt at examination had taken place earlier.

In addition, it is successfully claimed that the Court of Appeal should not have left it unaddressed whether there was a relevant chance at law that a reasonably competent and reasonably acting doctor during a timely examination would have chosen the optimum treatment. The loss of such a chance could after all lead to loss for the claimants that is eligible for compensation. The mere finding of the expert appointed by the court – who declared that the chance that earlier treatment would have led to a better result, was not big – cannot carry the view of the Court of Appeal that this chance was not relevant at law.

In view of the foregoing, the Supreme Court overturned the judgement of the Court of Appeal in The Hague and refers the case to the Court of Appeal in Amsterdam for further hearing and ruling.

Lost chance and proportional liability
In his Opinion to the judgement of the Supreme Court, Advocate General Hartlief sets out the doctrines of lost chance and proportional liability beautifully:

‘3.4 Application of the lost chance doctrine is appropriate if there is a violation of a standard and this violation has led to the loss of a chance of a better result. This makes the lost chance doctrine an instrument for loss assessment in the event of uncertainty on the question to what extent the error has led to loss: the claimant does not get ‘everything’ (in this case: full compensation based on the blindness not occurring) but also does not come away empty handed. In the Deloitte judgement /[…] [HR 21 December 2012], the lost chance doctrine is distinguished by the Court from proportional liability. The latter doctrine offers an instrument in cases of causality uncertainty and spreads, unlike the all-or-nothing-approaches as presumptive evidence, application of Article 6:99 of the Dutch Civil Code or of the rule of reversal, the burden of such across both parties, claimant and defendant. It appears from said judgment that the Court considers the distinction between lost chance and proportional liability important as on application of the doctrine of proportional liability – apparently different than in the application of that of the lost chance – reticence must be observed. This distinction has been received with approval by some commentators but previously rather critically by others.
3.5 […] Yet, and that is where in my opinion the critics put the emphasis, it can also be dependent on the perspective and debate in the proceedings whether a case manifests itself as a loss problem or a problem of causality (uncertainty). In the first case, the lost chance doctrine may come to the fore, in the second it will actually be the doctrine of proportional liability […] 3.6 The uncertainty regarding the harmful consequences of a medical error can be solved both along the route of causality (proportional liability) and along the route of loss estimate (lost chance). […] Both on application of the lost chance doctrine and that of proportional liability, a solution is offered for one and the same problem: uncertainty about what would have happened without the error. In both cases, there is the risk that someone is held liable for loss that he has not, or not to the degree accepted by the court, caused. The proportional liability doctrine is only relevant if there it is not a very small chance that the error has caused the loss (in that case the claim is rejected and the claimant leaves empty handed) and neither in the event of a very large chance, as in that case the claim is awarded in full. There is, therefore, a lower and an upper limit. From this perspective, it is important that the Court, also on application of the lost chance doctrine, employs in any event a lower limit: after all, there has to be a realistic, i.e. not a very small, chance. […] 3.8 On the application of the lost chance doctrine, the requirement of the condicio sine qua non relationship between the error and the loss is satisfied if without the violation of the standard (unlawful act or, such as here, attributable failure) there would have been a realistic chance of a better result. The condicio sine qua non relationship here is therefore between the error and the lost chance of a better treatment result (and not the condicio sine qua non relationship between the professional error and [claimant 1] blindness). In that respect, there is therefore a factual assessment and not a normative criterion. Whether or not there is subsequently compensable loss (a sufficiently realistic chance) (as appeared already before) may then, in turn, depend on normative elements. […] 3.10 For granting compensation in respect of lost chance, it is necessary that the injured party has been deprived of a realistic (which means: not very small) chance of success. It follows from the case law of the Court that for application of the lost chance doctrine, it is not required that a large chance of success has been lost. […]

Conclusion
In answering the question whether a patient has lost a chance of a better treatment result, it must first be assessed whether there have been violations of the standard of that which befits a reasonably acting and reasonably competent professional colleague.

If it is concluded that there have been violations of this standard, then subsequently, in the assessment of the causal link between the violation of the standard and the alleged loss, a comparison must be made between the factual situation after the violation of the standard and the hypothetical situation such as it would have been if the violation of the standard had not occurred.

As regards the factual situation, it concerns the determination of that which actually occurred. As regards the hypothetical situation, it concerns the determination of what actually would have happened without the violation of the standard. According to the Supreme Court, this hypothetical situation must therefore not be based on the standard of a reasonably acting and reasonably competent professional colleague but on the treatment that would have actually have taken place, be it that the principle must be that no violation of the standard would have occurred.

By Daan Baas, lawyer