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Medical Negligence and Consent: The Expert's Role

Medico Legal

The law concerning consent to medical treatment changed in 2015 with the Supreme Court ruling in Montgomery v Lanarkshire Health Board. So what is the medical expert's role now in giving evidence issues of consent? 

Patient Consent.The Law

Prior to the Montgomery decision, whether medical advice was adequate was a matter judged by the standards of the medical profession. The Bolam test applied. Advice was adequate if a responsible body of doctors practicing the same discipline would have offered the same advice. So a vascular surgeon's advice about the merits of, say, amputation was judged according to whether a responsible body of vascular surgeons would have given similar advice. If so, the advice was adequate and there was no breach of duty.

With Montgomery, the law changed. The Supreme Court held that Bolam test did not apply to advice. A doctor's duty is now to take reasonable care to ensure that a patient is aware of the material risks of a recommended treatment, and the material risks of reasonable alternative or variant treatments. A risk is considered material if, in the circumstances of a particular case either:

• a reasonable person in the patient's position would be likely to attach significance to the risk (I call this the first limb), or

• the doctor is or should reasonably be aware that the particular patient would attach significance to it (the second limb).

Patient Autonomy

Underlying the Supreme Court's decision is respect for patient autonomy. It is for the patient to decide what risks to take. Assessing risks and considering their significance for a particular person is not just a medical matter. Different people will place different weights on different risks. Their decision will be affected by their values, goals and concerns generally. Because considering the significance of risks for one's own life is not a uniquely medical decision, the role of experts in giving evidence on this issue is now limited.

A report by the Kings Fund (Patient Preferences Matter) concludes that doctors not always as good as they think at understanding what patients want. In one example, doctors were asked what percentage of patients undergoing treatment for breast cancer gave top priority to preserving the breast. Doctors put the figure at 71%. In fact when patients were asked, the figure was only 7%. This is an extraordinary difference. When I mentioned this to a breast surgeon he said, 'But we were always taught at medical school to preserve the breast if at all possible'. It seems he was taught wrongly. There are numerous other examples in the report of doctors misunderstanding their patients' preferences both in terms of treatment and outcomes. This indicates quite how important that the Montgomery decision was in enshrining patient autonomy in the law's approach to patient consent.

Following Montgomery, a doctor must now take reasonable care to work out what each patient would regard as material. The starting point is to consider what a reasonable person like this particular patient would expect to be told. The court expects there to be a dialogue between doctor and patient. Through discussion the doctor works out what the patient's concerns are and assesses what information to provide. Armed with relevant information (and what is relevant will vary from person person), patients can make their own decisions and properly exercise autonomy.

Advising Patients: Separate Roles I

In the light of Montgomery, advising patients in effect involves what I suggest are 2 distinct roles. One involves the exercise of medical skill. The other does not.

The first role involves assessing the range of reasonable treatment options. There is never just one possible approach to a medical issue. Even if medicine can only offer one treatment there is always an option of not having treatment. The doctor then must consider the risks and benefits of alternative treatments. Exercising this role requires medical skill.

The other role is to identify which risks are material for each patient. This normally means applying what I have called the first limb and considering what a reasonable patient like this patient would want to know. In some circumstances the second limb applies because the doctor is aware that this particular patient attaches significance to a risk a reasonable patient might not. Identifying what risks are material to this patient is not an exercise of uniquely medical skill. Some considerations will be non-medical. And they will differ from patient to patient.

Medical Advice: The Role of Expert Evidence

The medical expert can assess the exercise of the first role but not the second. The expert can identify:

• the range of reasonable treatment options; and

• the risks and benefits each.

However, it is not the expert's role to give an opinion about the exercise of second role. The court does not need expert evidence on the point. Experts stray outside the ambit of their role if they comment on it.

The expert should not now comment on:

• whether the discussion with the patient was adequate; and

• whether particular risks are material risks for this individual patient.

Assessing these issues involves an appraisal of whether a patient's rights have been respected – whether they have able to exercise autonomy. In the words of Lords Kerr and Reed in Montgomery, 'Responsibility for determining the nature and extent of a person’s rights rests with the courts, not with the medical professions.'

Recent Cases

2 cases decided 2017 help to illustrate the role of the expert.

(a) Thefaut v Johnson [2017] EHWC 497

Mrs Thefaut underwent private spinal surgery and suffered a poor outcome. She was found to have been given inadequate advice as to the risks and had therefore not given valid consent. The court heard expert evidence as to the risks and benefits of surgery as opposed to conservative management. It found that the surgeon's advice was inaccurate – his figures were wrong. He under-estimated the risks of surgery, overestimated the benefits and failed to advise that with conservative treatment she would probably recover within a year.

The expert evidence addressed the first of the 2 roles identified above. The question was not whether the risks of which Mrs Thefaut was advised were material – it was whether the medical information she was given was correct. Expert evidence at this point was appropriate.

(b) Webster v Burton Hospitals NHS Foundation Trust [2017] EWCA Civ 62

The first post-Montgomery case to reach the Court of Appeal concerned a failure by an obstetrician to advise a pregnant woman adequately. Scans showed some unusual features. Although the obstetrician was not aware of their significance, had he checked he would have discovered that they were associated with an increased risk of antenatal foetal death. Experts properly gave evidence as to what those risks were and the options for managing the pregnancy (induction at term or continuing after the expected date of delivery). Induction would have minimised the risk. However the nature of the discussion with the woman and the assessment of the significance of those risks for her fell within the second role.

The claim was tried a few months before the Supreme Court made its decision in Montgomery. The trial judge applied the Bolam test to the question of consent (in line with the law as it was understood to be at the time). He found that the obstetrician should have carried out some research and would have discovered the association. But should he have gone on to advise the mother? The Defendant's expert thought a responsible obstetrician would not have regarded the unusual scan findings as significant. It was therefore unnecessary in his view to discuss them with the mother. The Claimant's expert thought he should have discussed them but only because the obstetrician was pursuing an unusual course of action in failing to induce. The claim failed at trial.

After Montgomery, the Court of Appeal heard the mother's appeal. It rejected the evidence of both experts on the issue of whether the obstetrician should have advised the mother of the risk. It found that she was entitled to be told. In her mind this would have been a material risk. This was not a matter for experts and their views on the point were rejected.


With Montgomery the landscape in relation to consent to medical treatment has changed. This has implications for experts. Their role has changed. They can give evidence in defining the range of reasonable management options and the risks and benefits of those options. What they should not now address is whether the discussion with a patient was adequate, whether particular risks were material to the patient and whether consent was valid. Assessing these issues is not a matter of medical skill. It involves an assessment of the patient's rights and is a matter for the court and not the medical profession.

Paul Sankey is a solicitor and partner at Enable Law, specializing in clinical negligence claims for patients. https://www.enablelaw.com/team/paul-sankey/

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