Causation in clinical negligence – does the Pomphrey case change or restate the law?

Posted: 05/09/2019

Earlier this summer judgment was handed down in the case of Pomphrey v Secretary of State for Health and Anor [2019] 4 WLUK 483. On the face of it, this was a case involving a delay in diagnosis and management of Cauda Equina Syndrome (CES). Both breach of duty and causation were denied and, in giving judgment, the judge took the opportunity to consider carefully how causation should be addressed in cases involving a negligent delay in surgery and the materialisation of a recognised, non-negligent complication of surgery.

Philippa Luscombe, partner in the clinical negligence team and head of the Cauda Equina claims team considers the judgment and its implications below.

What is Cauda Equina Syndrome (CES)

CES is a condition whereby a disc in the spine ‘slips’ and compresses a specific set of nerve roots at the base of the spinal cord – the Cauda Equina roots. These are sensitive nerves which, if compressed for an extended period, will suffer permanent damage. These nerves control bladder, bowel and sexual dysfunction as well as affecting lower limb sensation and stability.

Because of the implications of permanent damage, CES is regarded as a surgical emergency and, if suspected and at an early stage, urgent steps need to be taken to exclude or confirm a diagnosis and arrange surgery if present.  Beyond a certain time and progression of symptoms the urgency is removed as the damage will already be permanent.

Pomphrey v Secretary of State for Health and Anor [2019] 4 WLUK 483

In this instance, the claimant made a number of allegations of failings in his medical care prior to him coming under the care of a neurosurgical team for surgery and he alleged that these led to a delay in diagnosis of his CES. The judge considered both the factual and expert evidence available and found against the claimant on all of those allegations. He concluded that there had been no breach of duty on the part of any of the medical practitioners involved in his care prior to diagnosis and that his earlier symptoms had been due to spinal stenosis and not CES.

However, the claimant had also alleged that his neurosurgeon had delayed arranging his surgery for an unacceptable period of time. Of note is the fact that, by the time the claimant came under the care of the surgeon, he was past (in both time and clinical presentation) what would generally be regarded as the “window of opportunity” for surgical intervention to produce a better outcome. In short, he needed surgery but was no longer a surgical emergency.

The judge considered the evidence and found in favour of the claimant on this point. The delay between him seeing the neurosurgeon and having surgery was around 40 days (including the Christmas period) and the judge found that the latest he should have undergone surgery with proper care would have been 10 days earlier than it occurred.

Having identified a breach of duty, the judge then had to consider causation. The focus of the claimant’s case against the neurosurgeon was not that the delay in surgery resulted in a worse outcome in terms of his CES symptoms as it was accepted that ‘the damage was done’ by the time he saw him. Instead the claimant tried to use a consent case to argue that the recognised complications of the surgery arising from a dural tear which he suffered would have been avoided.

Chester v Ashfar [2004]

In the 2004 case of Chester v Ashfar, the claimant succeeded in establishing that she had not been properly advised about the risks of proposed spinal surgery and so had not given informed consent. She too suffered a recognised, non-negligent complication of the surgery.

Her case was that, due to the nature of the risks and complications of the proposed procedure, if she had received proper advice on these she would have wanted to go away and think about things before proceeding. She accepted that she would ultimately have had the surgery but not at the time that she did.

In causation terms, her case was that the risk of such a complication materialising was minimal. It only happens in a small number of cases and, therefore, on the balance of probabilities the same complication would not have occurred with the same operation performed on another day. The court accepted that case as an exception to the general causation ‘rule’ that the breach of duty must have caused the damage. Since then consent cases have often been run on that basis where a claimant can establish that they would not have had the treatment at that time with appropriate advice and that the recognised complication which eventuated was only a relatively small risk.

Pomphrey judgment

In Pomphrey, the claimant sought to apply the same test but to a different scenario. He argued that if his surgery had been earlier then, on the balance of probabilities, the same complication would not have occurred.

The judge considered the argument but did not accept it. In this instance, it was clear that the surgery would have been the same surgery in the same hospital with the same surgeon, just 10 days earlier than in fact occurred and with no material change in the claimant’s condition. Therefore, the risk profile would have been the same as the surgery that did take place.

His reasoning was that “a general risk of a particular complication which is based on the statistical cohort of a large number of different surgeons (and usually containing a range of different causes and circumstances) must yield to more refined evidence of the risk of the complication arising from the technique of the particular surgeon undertaking the same operation on different days. So the focus must be on the particular operation in question”.

The judge was of the view that the same operation performed by the same surgeon in similar circumstances 10 days earlier would have carried the same risk and so the complication of the dural tear would still have occurred.

At first glance this might seem a threat to the long-established Chester principle. Although in some cases the claimant may well have had the same procedure but with a different surgeon or in different circumstances and so a different risk profile, that will not always be the case. However, in his obiter comments at the end of the judgment the judge addressed this.

It was clear that his view was that the Chester test was not applicable here - rather than that he did not accept it or sought to modify it. He made the point that Chester was about a patient not being advised of risks of which they would have been sufficiently concerned about not to go ahead with the proposed treatment at that time if properly advised. He also said that the House of Lords felt that when such a claimant then suffers injury, having not been warned of the risks, they should recover.

In Pomphrey, the breach of duty was about the timing of the surgery and breach of duty by way of delay had no impact on the risks inherent in the procedure (of which the claimant was aware). The judge was clear that the House of Lords in Chester had identified a specific scenario whereby a claimant should be able to recover with an exception to the normal causation requirement that the breach of duty must have caused the damage. But this case was not a Chester scenario and there was no evidence in this case that the breach by way of delay had any impact on the risk inherent or the fact it materialised. Therefore, the claimant should not recover.  

The surgeon owed no duty to avoid inherent risks and the breach of duty involved had no bearing on the probability of injury occurring where there had been no change in the claimant’s condition during the period of delay.

The judge made clear that his decision was in part a factual finding. Having heard the surgeon’s explanation about why and how the dural tear occurred, he formed the view that it would have happened in this particular case whenever the surgery took place. He looked at why it occurred and formed the view that those reasons meant that, on this particular patient, that outcome from surgery was always likely.

Pomphrey does not therefore change the law at all in terms of either consent cases and/or causation. But there is scope for defendants in consent cases to try to use the factual approach to argue that a particular claimant was always likely to suffer a particular complication because of the specific circumstances of their case. We may well see a case on this issue go through the courts in the future.

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