Key elements a neurosurgical expert report must address in delayed subdural haematoma diagnosis claims

Chronology and clinical presentation

A neurosurgical expert report assessing delayed diagnosis of a subdural haematoma must establish the chronological relationship between the claimant’s clinical presentation and the diagnostic data available to the treating team at the material time. The expert applies the legal principles from Bolam v Friern Hospital Management Committee [1957] and Bolitho v City and Hackney Health Authority [1998] to determine whether the clinical team’s actions aligned with a responsible body of medical opinion.

The report should identify the specific clinical features that, in the expert’s opinion, warranted urgent neuroimaging at each relevant time point. This assessment depends on the contemporaneous records, including triage notes, nursing observations, and any available imaging reports. Where records are incomplete, the expert must state the limitations this imposes on their ability to reconstruct the clinical timeline.

Standard of care and breach of duty

The expert must define the standard of care by reference to the clinical information available to the treating team at the time of the alleged delay. This involves evaluating whether the decision to monitor rather than scan, or to delay imaging, fell within a range of reasonable practice supported by a responsible body of neurosurgical opinion.

Key considerations include:

• The claimant’s neurological status at initial presentation, including Glasgow Coma Scale score, focal deficits, or signs of raised intracranial pressure.
• Whether the clinical signs—such as headache, confusion, or deteriorating consciousness—should have prompted immediate neuroimaging under the relevant clinical standards at the time.
• Whether the decision to observe rather than scan was a reasonable exercise of clinical judgement, given the patient’s history and presentation.
• The extent to which the treating team’s actions aligned with or departed from accepted practice, as documented in contemporaneous records.

Evidential foundation for retrospective analysis

The expert’s opinion on the adequacy of the diagnostic timeline relies on a complete review of primary documentation. This includes:

• Initial triage and admission records, including vital signs and neurological assessments.
• Nursing observation charts, particularly any documentation of deterioration.
• Contemporaneous imaging reports, including any earlier scans that may have been performed.

Where records are missing or incomplete, the expert must explicitly state how this affects their ability to determine whether clinical decline was overlooked or appropriately managed. The imaging record forms the technical basis for the expert’s opinion, distinguishing between the actual findings at the point of delayed diagnosis and the inferred appearance of the haematoma at earlier disputed time points. If the evidence does not clearly establish the rate of expansion of the bleed, the expert should qualify their conclusions regarding the likely clinical effect of earlier intervention.

Causation: the but-for test and material contribution

The expert must address whether earlier diagnosis and intervention would have altered the claimant’s outcome. This requires application of the but-for test: whether, on the balance of probabilities, the claimant’s neurological deficit would have been avoided or reduced had the haematoma been diagnosed and treated sooner.

The report should:

• Compare the likely state of the haematoma and the claimant’s neurological condition at the hypothetical time of earlier diagnosis with the actual findings at the point of eventual intervention.
• Assess whether earlier surgical intervention—such as emergency craniotomy or burr-hole evacuation—would have prevented or mitigated the specific neurological deficit claimed.
• Distinguish between the primary injury sustained at the time of trauma and the secondary damage caused by the mass effect of the haematoma.

Where material contribution to the injury is argued, the expert must clearly define the specific portion of the deficit attributable to the delay, avoiding any suggestion that the delay generally worsened the claimant’s condition without measurable effect.

Discipline boundaries and handover of evidence

A neurosurgical expert’s opinion is typically confined to the management of the intracranial pathology. Other disciplines may be required to address related issues:

• An emergency medicine expert may opine on the initial triage and threshold for urgent imaging in the accident and emergency setting.
• An intensivist or anaesthetist may assess the management of physiological stability, ventilation, or monitoring.

In England and Wales, where both parties instruct experts, the court may direct discussions under CPR Part 35.12 to identify areas of agreement and disagreement. The experts may produce a joint statement, but this is not automatic and depends on the court’s directions or the parties’ agreement. The expert’s duty remains to the court, not to the instructing party, and they must maintain independence throughout.

Jurisdictional considerations for expert evidence

The procedural requirements for expert evidence differ across the UK:

• In England and Wales, reports must comply with Practice Direction 35, and experts owe an overriding duty to the court under CPR Part 35.3.
• In Scotland, the role of the expert is governed by the principles of the skilled witness, as outlined in Kennedy v Cordia (Services) LLP [2016], with procedures under Chapter 43 for personal injury cases.
• In Northern Ireland, expert evidence is governed by the Rules of the Court of Judicature.

Where a case involves cross-border elements, the expert must ensure their analysis respects the procedural and substantive rules of the jurisdiction in which the claim is brought.

Precision and utility of the expert opinion

The value of the neurosurgical expert’s opinion lies in its precision. The report must:

• Connect the clinical records to the specific allegations of delay, avoiding generic conclusions.
• Clearly state the evidential basis for the opinion, including any limitations imposed by missing or incomplete records.
• Distinguish between areas of certainty and those where the evidence is insufficient to support a definitive conclusion.

The report serves as the clinical foundation for the legal team’s assessment of whether the alleged deficiencies in diagnosis constitute a breach of duty and, if so, whether they caused the claimed injury.