Jessica Tuffin v University Hospitals Coventry and Warwickshire NHS Trust

In a clinical negligence claim involving mixed medical conditions, the claimant must prove on the balance of probabilities that the negligence either caused the injury or made a more than negligible causal contribution to it. The material-contribution principle does not dispense with proof that the negligent factor added to the cause of the injury; its mere presence in the sequence of events is insufficient.

Where several conditions may have contributed to an amputation, the court must identify the symptoms and signs that caused the decision and determine whether the negligent condition caused or materially contributed to them. A diagnosis of complex regional pain syndrome may be preferred where it better explains those symptoms than a deep vein thrombosis or post-thrombotic syndrome.

The claimant underwent elective spinal surgery in July 2015. The defendant admitted that it negligently failed to administer Clexane within 24 hours, causing an avoidable deep vein thrombosis and subsequent post-thrombotic syndrome.

The claimant later developed severe left-leg pain, ulceration and a fixed deformity, and underwent above-knee amputation in September 2018. The trial concerned whether the negligence caused or materially contributed to the amputation, including whether the claimant’s symptoms resulted from post-thrombotic syndrome, complex regional pain syndrome, or both.

1. Outcome. The defendant was liable for the DVT and post-thrombotic syndrome resulting from the admitted breach, but not for the complex regional pain syndrome or the above-knee amputation.
2. The claimant bore the burden of proving causation on the balance of probabilities. The court applied the approach in Bailey v Ministry of Defence [2008] EWCA Civ 883: the ordinary but-for test applies; where medical science cannot establish but-for causation, the claimant may succeed by proving that the negligent factor made a more than negligible causal contribution. The factor relied on must nevertheless be shown to have added to the cause of the injury, rather than merely having been present in the history.
3. The relevant causes of the amputation were severe allodynia, ulceration and the fixed position of the claimant’s knee and foot. The expert consensus was that severe allodynia was not consistent with DVT or post-thrombotic syndrome. The ulceration and fixed deformity were likewise not attributable to those conditions.
4. The court applied the Budapest criteria for CRPS. The decisive issue was whether another diagnosis better explained the signs and symptoms. It did not. The claimant was suffering from CRPS, which explained the symptoms leading to amputation.
5. The court rejected the inference that the DVT caused the CRPS merely because the conditions occurred in the same limb. The medical literature and expert evidence did not establish a satisfactory causal mechanism. The CRPS was more probably caused by the spinal surgery. The limited improvement following venous stenting showed that post-thrombotic symptoms had existed, but did not establish that they caused or materially contributed to the amputation.
6. The authorities relied on concerning material contribution, including Simmons v British Steel Plc [2004] UKHL 20 and the discussion of Bailey in Williams v Bermuda Hospitals Board [2016] UKPC 4, did not assist because the evidence failed to show that the DVT added more than negligibly to the causes of the amputation.