Patient factors in the treatment of chronic subdural hematomas

Chronic subdural hematoma (cSDH) recurrence after burr-hole drainage remains incompletely understood, and the role of adjunctive middle meningeal artery embolization (MMAE) in reducing recurrence is debated. We retrospectively analysed 261 consecutive patients who underwent single burr-hole drainage of a unilateral cSDH between 2017 and 2024 at a single academic centre (71.26 % male; mean age 71.50 ± 13.31  years), of whom 97 received MMAE and 164 did not. Recurrence was defined as reoperation for a recurrent hematoma within 90  days. With only 14 recurrences observed, the multivariable model was fitted with Firth penalization and all estimates are exploratory. Overall recurrence was 5.36 %. Recurrence did not differ significantly between patients who received MMAE and those who did not (4.12 % vs. 6.10 %; absolute risk difference 2.0 percentage points, 95 % CI, -4.6 to 7.4; p = 0.581), and the difference narrowed further when the analysis was restricted to the years in which MMAE was available at our institution (4.12 % vs. 4.79 %). Documented head trauma was the only covariate associated with recurrence (OR 0.15, 95 % CI 0.02-0.62). No interaction between MMAE and any patient factor was demonstrable, and no subgroup comparison survived correction for multiple testing. No recurrences occurred among the 58 patients with head trauma who received neither anticoagulation nor MMAE. These findings describe recurrence in a low-baseline-risk surgical cohort and generate a testable hypothesis: that the absolute benefit of MMAE scales with baseline recurrence risk, and that documented head trauma is a candidate marker of lower baseline risk.