Embolisation halves the chance of going back to theatre for a chronic subdural haematoma

Design

Systematic review and meta-analysis of randomised controlled trials, RoB-2 assessed, PROSPERO registered

Population

1,889 adults with confirmed chronic subdural haematoma across 7 randomised trials

Primary outcome

Haematoma recurrence or persistence

Effect

Recurrence RR 0.63 (95 per cent CI 0.46 to 0.85); reoperation RR 0.39 (0.28 to 0.56); serious adverse events RR 0.87 (0.72 to 1.06)

Chronic subdural haematoma is now largely a disease of older people on antithrombotics, and burr-hole drainage leaves a substantial minority coming back. Middle meningeal artery embolisation aims at the dural neovascularisation that drives rebleeding. Seven randomised trials with 1,889 adults, searched to July 2025, were pooled to test it as an addition to standard treatment.

Recurrent or residual haematoma fell (risk ratio 0.63, 95 per cent CI 0.46 to 0.85) and reoperation fell substantially further (0.39, 0.28 to 0.56). Serious adverse events did not rise (0.87, 0.72 to 1.06), and neither did neurological death, all-cause mortality, or poor functional outcome. Haematoma resorption itself did not differ, which is consistent with the mechanism - the procedure prevents refilling rather than clearing what is there. Subgroup and sensitivity analyses held across age, timing of the procedure and length of follow-up.

The finding that benefit is independent of timing matters practically, because it removes the argument that embolisation must be done in a narrow window to be worth arranging. What the evidence does not answer is who should get it: with recurrence concentrated in particular patients, an unselected policy will treat many who would not have recurred. For an older patient facing a second general anaesthetic and a second craniotomy, though, a 61 per cent relative reduction in reoperation is a large number, and it is worth asking the neurosurgical service whether embolisation is available before assuming it is not.

• Ask whether middle meningeal artery embolisation is available when a chronic subdural haematoma is drained, particularly in a frail patient.
• Do not expect faster resorption; the effect is on refilling, not clearance.
• Note that timing did not modify the benefit, so a delay in arranging it is not a reason to abandon it.
• Serious adverse events did not rise, but the trials were not powered for rare procedural harms.
• Review the antithrombotic indication at the same time; it is the other modifiable driver of recurrence.

The statistics, in plain English

A risk ratio of 0.39 for reoperation means a 61 per cent relative reduction, and the interval from 0.28 to 0.56 sits well clear of 1.0 - this is a solid finding across seven randomised trials. The safety result, 0.87 with an interval reaching 1.06, is a null: it does not show embolisation is safer, only that no increase in serious adverse events was detected at this sample size. Because the trials pooled different patient selections, the absolute benefit in your own patient depends on their baseline recurrence risk, which this analysis does not stratify.

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