High Court considers causation in clinical negligence

22 May 2019 by

causation in clinical negligence spinal diagram

Pomphrey v Secretary of State for Health and Anor [2019] 4 WLUK 483— decision not yet on Bailii but available on Lawtel.

This case concerned an alleged failure to diagnose compression of nerve roots leading to cauda equina and alleged delay in operating urgently.  It raises an important issue in relation to causation and the applicability of the famous decision of Chester v Afshar [2004] UKHL 41.

The Claimant advanced a range of arguments on breach of duty against a number of individuals in respect of a failure to refer for earlier surgery for symptoms of early onset cauda equina, all of which failed having regard to a careful analysis of the factual and expert evidence.

The judge did, however, find that there was a breach of duty in respect of the delay between seeing the consultant neurosurgeon on 14 December 2011 and the actual operation which took place on 24 January 2012. The negligent period of delay was found to be 10 days. 

That breach of duty opened the door to the Claimant running an argument based on Chester v Afshar and Crossman v. St George’s NHS Trust [2016] EWHC 2878 that the same dice rolled on another day would not have resulted in ‘snake eyes’; viz. an injury which was an accepted complication of the operation, estimated at around 5%. This being a case where the consultant in question accepted that the injury had been “inadvertent” and therefore not one that necessarily would have occurred.

Dismissing the claim on the facts but also, obiter, on the law, the judge found that the operation, if performed 10 days earlier, would not have changed the risk profile of the operation. It would have been performed with “the same surgeon, physiology, difficulty with depth, technique, and use of punch in the same spot.”  The crucial reasoning of Judge Cotter at [274] 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 therefore found that, “had there been no delay the operation would still have been carried out by Mr P. and the same dural tear would have occurred.

In his obiter remarks at the end of the judgment the judge also accepted the Defendant’s case on the law, and rejected the Claimant’s argument that Chester represented a change to the basis of establishing causation in a case where the starting point is that the breach of duty did not affect the risk inherent in the procedure.

In reasoning in this way the judge was obliged to, and did, distinguish the decision of HHJ Peter Hughes QC in Crossman, explaining that, in his view,  HHJ Hughes QC had not considered the question of the scope of duty of care, nor addressed the approach of the court in Chester to establishing causation on conventional principles, saying at [290]:

given that there was no direct link between the admitted negligence and the risk arising from the surgery (which he would have undergone in any event) and no material alteration in the risk had the operation been performed three months later it is difficult to reconcile the learned Judge’s [HHJ Hughes’] approach with the unanimous view of their Lordships [in Chester] as to the problems with reliance upon conventional causation in such circumstances.

His conclusion on the law was essentially that, given that the scope of the relevant duty which was breached was a duty to avoid unreasonable delay, he would have declined to follow the approach in Crossman, and would have found that simple ‘but for’ causation, based solely upon the operation taking place on different day would not have been sufficient, without more, for the Claimant to establish causation.  Indeed he said that to do so would “drive a coach and horses” through well-established causation principles.


This case is particularly interesting for two reasons. First, because of what the judge says on factual causation at [274] about the general risk of a particular complication yielding 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. 

Second, because of his careful analysis of the speeches of the House of Lords in Chester and his distinguishing of HHJ Hughes QC’s decision in Crossman. The judge’s analysis is that Crossman has been impliedly overruled by the Court of Appeal’s decision in Meadows v Khan [2019] EWCA Civ 152 not least because the Court of Appeal has re-affirmed in Khan the limitations of the but-for test for causation given ‘scope of duty’ considerations. The net result of the judge’s conclusion was that, as the Defendant cogently argued:

the risk that the Claimant would sustain a dural tear was a risk inherent in that surgery and the delay in operating did not alter the magnitude of the risk; the injury was liable to occur whenever the surgery was performed…. It would be wrong to permit the Claimant to recover damages by changing the scenario in an irrelevant detail which has no bearing on the probability of the injury occurring i.e. by bringing the time of the surgery forward (absent any deterioration in condition). Moreover, the Defendant’s scope of duty did not extend to avoiding a risk inherent in the surgery that he was to undergo. The fact that the Claimant sustained a dural tear was coincidental and not within the scope of the Defendant’s duty.

Jeremy Hyam QC is a barrister at One Crown Office Row.

Andrew Kennedy, also of One Crown Office Row, appeared for the Defendant in this case. He did not contribute to this article.

A version of this article appeared in the One Crown Office Row Quarterly Medical Review — Spring 2019, which can be found here.

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