Chronic Subdural Haematoma: Systematic Review Highlighting Risk Factors for Recurrent Bleeds

Abstract

Introduction: Chronic subdural haematoma (CSDH) is one of the commonest forms of intracranial
haemorrhage. Surgical drainage of CSDH is a routine operation in the modern neurosurgical
practice which has shown to be the most effective way in treating this entity; however, the
incidence of recurrence of the haematoma post operatively remains as high as 26.5%. The risk
factors for CSDH recurrence remains an area of ongoing research.
Objective: We have conducted a systematic review to evaluate the available literature addressing
the risk factors for CSDH recurrence, aiming to minimise or at least identify patients at
higher risk of recurrence in order to decrease associated morbidity.
Methods: Ovid via Medline, PubMed, and Google scholar databases were searched for eligible
studies, search results were then limited to studies in English language, Humans and studies
published within the last 5 years. The included studies were critically appraised using the Critical
Appraisal Skills Programme (CASP) tool, and each study has then been ranked using the
Harbour and Miller hierarchy of ranking.
Results: Based on available evidence, we classified the risk factors associated with recurrence
to patients’, radiological, and surgical factors. Patient factors include history of seizures,
trauma, alcoholism, brain atrophy, and presence of CSF shunts, while the role of diabetes in
relation to the recurrence is controversial. Radiologically the presence of air in the subdural
space post-operatively, the width of the haematoma, and the presence of bilateral CSDHs are
associated with increased risk of recurrence. While the predictive value of multiple membranes
in the CSDH remains controversial. Surgically, the risk of recurrence was noted to be higher in
patients with parietal or occipital compared to those who had frontal burr hole drainage, also
placing a subdural drain decreases the chance of recurrence and some evidence showed better
outcomes for frontally placed drains. The role of anti-inflammatory agents (including steroids)
remains an area of ongoing debate.
Conclusions: Risk factors for CSDH can be divided into patients’, radiological, and surgical
factors. We encourage health care providers to minimize if not prevent potentially avoidable
factors. Patients with increased risks for recurrence should be identified early by the treating
team and when possible should be informed about their higher than usual risk of recurrence.
Moreover this review highlights the general lack of a sufficiently powered class I evidence addressing
this topic and that further research is required in this topic.