Causation – establishing the difference the breach of duty made

This is one of the most difficult areas to address in civil claims, both for lawyers and for their medical experts, even more so if there is a pre-existing condition.  In doing so, the medical expert must be aware of, understand and apply several legal tests.

Firstly, the ‘Egg-Shell Skull’ principle means that someone who causes injury to another person must take that other person as they are. Therefore, if the injured person has a vulnerability or pre-existing condition with the result that the impact of the accident or injury on them is more severe than would normally be expected, the person who causes the injury is responsible for all of the consequences as they arise in this individual and damages will not be reduced because of this increased vulnerability.

On the other hand, damages will not be awarded for what would have occurred in any event as a result of this pre-existing condition, but only for the consequences of the breach of duty – how the claimant’s life has been affected by the breach of duty. The expert has therefore to help identify the difference between the situation resulting from the breach of duty (and the likely future prognosis) and the situation as it would have been but for the breach of duty.[1]

Approach to the evidence

The expert must therefore first address the issue of what the claimant’s functioning would have been over time had the breach of duty not occurred.  Then the expert addresses what the claimant’s situation has in fact been and will be, and finally describes what the significance of that difference is, in terms of symptoms, function and consequences.

If the breach of duty has long-term effects then it is necessary to continue to compare into the future the situation as it would have been in the absence of the accident with what it will now be. For the future proof is no longer necessary on the balance of probabilities but the likelihood of both situations (the ‘but for’ situation and the situation consequent on the accident) must be compared according to the level of risk.

A claimant with a degenerate spine who suffers a disc prolapse in an accident can recover damages for the symptoms and restrictions consequent on the prolapse, but in assessing damages the fact that a prolapse might well have occurred in any event in the absence of an accident will be highly relevant.  The expert must seek to set out what would probably have happened in the absence of the accident – the likelihood of a prolapse, the events likely to give rise to it, it’s timing, it’s treatment etc – and compare that and the consequences to what has in fact occurred.  In that way the consequences of the accident (the damage caused by the accident) can be identified and damages assessed.  Easily stated as a principle, but not necessarily straightforward to address and to justify in a medical report.

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[1] See Ch 6 (sections 6.1, 6.2 and 6.5) of Writing Medico-Legal Reports in Civil Claims – an essential guide

Relying on the burden of proof to dismiss a complicated claim

In Barnett v Medway NHS Foundation Trust [2017] EWCA Civ 235 the Court of Appeal considered an appeal against the trial judge’s dismissal of a clinical negligence claim on the basis that the claimant had failed to prove the claim on the balance of probabilities.  The judge did not therefore make express findings as to which experts’ evidence carried greater weight.

It is rarely that it is considered appropriate for a claim to be resolved on this basis.  In Stephens v Cannon [2005] EWCA Civ 222 it was said:

A court which resorts to the burden of proof must ensure that others can discern that it has striven to make a finding in relation to a disputed issue and can understand the reasons why it has concluded that it cannot do so. The parties must be able to discern the court’s endeavour and to understand its reasons in order to be able to perceive why they have won and lost. An appellate court must also be able to do so because otherwise it will not be able to accept that the court below was in the exceptional situation [my emphasis] of being entitled to resort to the burden of proof.”

In Verlander v Devon Waste Management [2007] EWCA Civ 835 the Court of Appeal stated that:

First, a judge should only resort to the burden of proof where he is unable to resolve an issue of fact or facts after he has unsuccessfully attempted to do so by examination and evaluation of the evidence. Secondly, the Court of Appeal should only intervene where the nature of the case and/or the judge’s reasoning are such that he could reasonably have been able to make a finding one way or the other on the evidence without such resort.…

In Verlander the Court of Appeal emphasised that the use of the word “exceptional” in Stephens meant no more than that resorting to the balance of probabilities is only necessary where on the available evidence, conflicting and/or uncertain and/or falling short of proof, there is nothing left but to conclude that the claimant has not proved his case.

The burden of proof remains part of our law and practice – and a respectable and useful part at that — where a tribunal cannot on the state of the evidence before it rationally decide one way or the other.”

In Barnett the claimant suffered from a rare congenital condition, hypophosphatasia, resulting in deficient bone mineralisation and a tendency to stress fractures.  He was admitted to hospital with acute pain at the back of his thigh.  He was given antibiotics, and was discharged home after 2 weeks in hospital.  He was readmitted as an emergency just over a month later with an abscess in his spine at L5/S1 and infarction of the lower thoracic spinal cord, resulting in paraplegia at T7.

The issues at trial revolved around what blood cultures, if taken prior to the administering of antibiotics during his first admission to hospital, would have revealed, and whether that would have resulted in more effective treatment of the infection.  The defendant argued that it was likely that even if cultures were obtained no infection would have been detected at that time.  The claimant was markedly vulnerable to infection and was on a combination of drugs which would probably have diminished the effectiveness of his immune system.

The 2 experts called had clearly found answering the questions very difficult.  As the Court of Appeal summarised:  “Not only was the medicine particularly difficult, but the evidence of the 2 microbiology experts was expressed in difficult and shifting terms … both experts shifted position.  The evidence of both experts was somewhat rebarbative … Taken as a whole [the claimant’s expert’s] evidence fell short of establishing probability.

The trial judge was therefore entitled, on the particular facts of this case and given the state of the expert evidence at trial, to conclude that the claimant had failed to discharge the burden of proof, and therefore without concluding that either expert was probably right or probably wrong.  The judge was however criticised for the brevity of his judgment in justifying this approach.

Joint discussion

An additional point of note, and remarked upon with some surprise by the Court of Appeal, was that at the joint discussion the microbiologists had not been asked to consider whether cultures taken following the initial admission to hospital would have revealed infection, although this was a very important issue and was considered at trial in the oral evidence of the experts.  Primary responsibility for preparation of an agenda for a joint discussion lies with the lawyers.  Experts often comment that an agenda is of little assistance, but here is an example of a case where one of the issues which was of considerable importance for the claim was omitted by the lawyers and was not therefore discussed prior to the trial.

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