Update on the rules of consent

Duce v Worcester Acute Hospitals NHS Trust [07.06.18]

Date published





The Court of Appeal recently provided clarity on the rules relating to liability where the injury is directly linked to consent. It reinforces the materiality rule established in Montgomery v Lanarkshire Health Board [2015] and confirms the limited scope of the causation principle established in Chester v Afshar [2004].

The rules as established in Chester and Montgomery

Chester represented a departure from traditional causation principles. In this case, Ms. Chester consented to spinal surgery, which had a 1-2% risk of worsening her condition, which she was not made aware of. Dr. Afshar argued, in accordance with a responsible body of medical opinion, that it was not mandatory to advise Ms. Chester of this risk. In the event, the risk materialised and Ms. Chester suffered cauda equina cord compression.

The House of Lords held that Ms. Chester should have been warned of the risk. Ms. Chester did concede that she would have still had the surgery but would have taken time to consider it. Therefore, the surgery would have taken place on a different date and perhaps with a different surgeon, but the chances of the complication would have remained the same.

Part of the legal test applied was:

On policy grounds I would hold that the test of causation is satisfied in this case. The injury was intimately involved with the duty to warn…. It was the product of the very risk that she should have been warned about when she gave her consent.

Montgomery concerned hypoxic brain injury secondary to delivery complicated by shoulder dystocia. Mrs. Montgomery claimed she should have been warned of the 9-10% risk of shoulder dystocia and been offered a caesarean section. This complication would not have occurred from a caesarean section.

The Health Board defended the claim on the basis that not advising Mrs. Montgomery of the risk was in accordance with responsible practice. The Supreme Court however, favoured a patient-centred legal test, specifically providing:

…a duty to take reasonable care to ensure … the patient is aware of any material risks involved in any recommended treatment, and of any responsible alternative or variant treatments….

Duce v Worcester Acute Hospitals NHS Trust

Mrs. Duce elected to undergo a total abdominal hysterectomy due to heavy periods. The consultant gynecologist advised of the risk of normal post-operative pain but did not advise specifically of the risk of developing chronic or neuropathic pain. Surgery was performed non-negligently, however Mrs. Duce sustained nerve damage and suffered chronic post-surgical pain. She argued that there was a failure to inform her at consent of this risk and would not have opted for surgery had she been warned.

The Judge at first instance held there was no duty to warn Mrs. Duce of the risk as this was not the advice that the profession gave at the time. In addition, the risk of suffering three to six months of numbness and pain was given and Mrs. Duce continued to have surgery that day. Mrs. Duce appealed on the following points:

  • The Judge did not address consent in accordance with Montgomery, as there was no discussion about what risks were material.
  • The legal test of causation derived from Chester should be used in this case even though Mrs. Duce would have proceeded to surgery. In essence, Mrs. Duce sought remedy for a defective consent process, the injury not being explained to her at consent.


The appeal was dismissed. The Court of Appeal held that Mrs. Duce had not established that the medical knowledge at the time considered there was a risk of chronic pain or neuropathic pain. Therefore, there was no duty to warn of the risk (Montgomery).

They also dismissed the argument to apply Chester. In considering this, Lord Justice Hamblen noted that the Chester judgment was laced with references to facts of that case and that their approach had a very narrow application. In essence, the test Mrs Duce sought to rely upon was not designed to amend the entirety of the law on causation. The case in Chester was made on conventional ‘but for’ principles in that on the alternative day for surgery, the 1-2% risk of complication would not have arisen on balance. As Mrs. Duce would have had surgery on the same day, causation was not established on the conventional basis.


The court have provided a reminder that the first stage of the Montgomery decision is to determine the risks known to clinicians at the material time. If the profession, at the time of the incident were not aware of a particular risk, then there can be no requirement to have conveyed that at consent, whether or not that is a material risk to a patient in hindsight.

The court then provided further reassurance that the decision of Chester is confined to the circumstances of that case. In consent cases, where disclosure of a material risk would have led the patient to defer the surgery, and as a matter of fact this risk materialised at the actual surgery, this will satisfy the “but for” causation.

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