How does research activity align with research need in chronic subdural haematoma: a gap analysis of systematic reviews with end-user selected knowledge gaps

BACKGROUND: Chronic subdural haematoma (CSDH) is increasingly common. Although treatment is triaged and provided by neurosurgery, the role of non-operative care, alongside observed peri-operative morbidity and patient complexity, suggests that optimum care requires a multi-disciplinary approach. A UK consortium (Improving Care in Elderly Neurosurgery Initiative [ICENI]) has been formed to develop the first comprehensive clinical practice guideline. This starts by identifying critical questions to ask of the literature. The aim of this review was to consider whether existing systematic reviews had suitably addressed these questions. METHODS: Critical research questions to inform CSDH care were identified using multi-stakeholder workshops, including patient and public representation. A CSDH umbrella review of full-text systematic reviews and meta-analysis was conducted in accordance with the PRISMA statement (CRD42022328562). Four databases were searched from inception up to 30 April 2022. Review quality was assessed using AMSTAR-2 criteria, mapped to critical research questions. RESULTS: Forty-four critical research questions were identified, across 12 themes. Seventy-three articles were included in the umbrella review, comprising 206,369 patients. Most reviews (86.3%, n=63) assessed complications and recurrence after surgery. ICENI themes were not addressed in current literature, and duplication of reviews was common (54.8%, n=40). AMSTAR-2 confidence rating was high in 7 (9.6%) reviews, moderate in 8 (11.0%), low in 10 (13.7%) and critically low in 48 (65.8%). CONCLUSIONS: The ICENI themes have yet to be examined in existing secondary CSDH literature, and a series of new reviews is now required to address these questions for a clinical practice guideline. There is a need to broaden and redirect research efforts to meet the organisation of services and clinical needs of individual patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00701-023-05618-2.