A commonly-used treatment for chronic subdural haematoma – the build-up of 'old' blood in the space between the brain and the skull, usually as a result of minor head injury in older patients – leads to a worse outcome than receiving no medication, suggests new research.

Published in the New England Journal of Medicine and led by the University of Cambridge, Dr. Ellie Edlmann, Clinical Lecturer in Neurosurgery at the University of Plymouth, co-authored the research – and explains why it is a landmark study.

“Chronic subdural haematoma is one of the most common disorders managed by neurosurgeons and mainly affects older people,” she said. “People affected often have headaches, confusion, balance problems or limb weakness, and can think they are suffering from a stroke. Instead it is a build-up of blood on the brain that causes the problem and surgery to drain the liquid collection is effective for the majority of patients. A commonly used steroid called dexamethasone has been growing in popularity as a treatment for chronic subdurals either alongside surgery or instead of it. However, consensus has been lacking regarding how effective it is, especially since no high-quality studies had been conducted until now. It’s a real landmark trial in neurosurgery, with findings that will change practice.”

With funding from the National Institute for Health Research (NIHR), a group of doctors and researchers from 23 neurosurgical units in the United Kingdom enrolled 748 patients with chronic subdural haematoma in the "Dexamethasone in Chronic Subdural Haematoma (Dex-CSDH)" randomised trial. Half the patients were randomised to a two-week tapering course of dexamethasone and the other half to an identical placebo, so that the patient didn’t know which treatment they received.

The vast majority of patients in both groups had an operation to drain the haematoma and had an improvement in their function at six months compared to hospital admission. However, the critical result of the study was that the patients who received dexamethasone had a much lower chance of a good recovery (84%) compared to those who received placebo (90%). This was primarily because the patients on dexamethasone suffered with more complications during their recovery, likely due to side effects of the drug. This highlighted the previously unknown risks of using this drug for chronic subdural patients, and should prevent it from being routinely prescribed in the future.

Peter Hutchinson, Professor of Neurosurgery at the University of Cambridge and the trial's Chief Investigator, said: 

"Chronic subdural haematoma has been steadily increasing in frequency over the past decades. Patients affected are often frail and have other co-existing medical conditions. Since the 1970s, dexamethasone has been used as a drug alongside or instead of surgery with a few studies reporting good results. Our trial sought to determine if dexamethasone should be offered routinely to all patients with chronic subdural haematoma or if its use should be abandoned. Based on our findings, we believe that dexamethasone should not be used in patients with chronic subdural haematoma anymore."

Dr. Angelos Kolias, Lecturer of Neurosurgery at the University of Cambridge and the trial's Co-chief Investigator, added: 

"The results of the study were surprising given that dexamethasone seemed to help reduce the number of repeat surgeries. However, this simply reinforces the importance of conducting high-quality trials with patient-reported outcomes as the main outcomes of interest."

Dr. Edlmann concluded: 

"Credit is due to all doctors and researchers from across the NHS who worked tirelessly in order to enrol all eligible patients in the trial; in particular, the role of trainee neurosurgeons, members of the British Neurosurgical Trainee Research Collaborative, needs to be highlighted. We sincerely thank all patients and their carers, as without their altruistic participation, this trial would not have been possible."

The full study, entitled Trial of Dexamethasone for Chronic Subdural Hematoma, is available to view in the New England Journal Of Medicine doi: 10.1056/NEJMoa2020473.