Adjunctive middle meningeal artery embolization is associated with lower 30-day readmission and mortality in chronic subdural hematoma: A propensity-matched national analysis.
Al Saiegh F, Kotzur T, et al. • Clinical neurology and neurosurgery • 2026
Adjunctive middle meningeal artery embolization was independently associated with lower 30-day readmission and in-hospital mortality in patients undergoing surgical evacuation for chronic subdural hematoma.
Key Findings
Results
MMA embolization was associated with significantly lower 30-day readmission rates compared to surgery alone.
30-day readmission rate was 8.8% in the MMA embolization group vs 11% in the surgery-alone group
Risk ratio 0.82 (95% CI 0.68–0.97; p = 0.024)
Result remained significant after Bonferroni correction for two primary outcomes
Analysis used modified Poisson regression with NRD survey weights and Taylor series linearization
2028 patients were retained after propensity score matching from an original cohort of 4918
Results
MMA embolization was associated with significantly lower in-hospital mortality compared to surgery alone.
In-hospital mortality was 2.4% in the MMA embolization group vs 4.5% in the surgery-alone group
Risk ratio 0.52 (95% CI 0.32–0.85; p < 0.001)
Result remained significant after Bonferroni correction
The E-value for the mortality association was 3.26 (1.63 for the upper 95% CI limit), suggesting the mortality benefit is unlikely to be explained by unmeasured confounding alone
Results
Readmission specifically for recurrent subdural hematoma was substantially lower in the MMA embolization group.
Risk ratio for readmission due to recurrent SDH was 0.37 (95% CI 0.19–0.72; p = 0.004)
This represents a 63% relative reduction in readmission for recurrent SDH
This was a secondary outcome analyzed in addition to the two primary outcomes
Results
Hospital charges were higher in the MMA embolization group, but there was no significant difference in length of stay.
Higher hospital charges were observed in the adjunctive MMA embolization group compared to surgery alone
No statistically significant difference in length of hospital stay was detected between the two groups
These were analyzed as secondary outcomes
Methods
The study identified 4918 patients undergoing surgical evacuation for chronic subdural hematoma in the National Readmissions Database from 2020 through 2022.
2218 patients received adjunctive MMA embolization and 2700 underwent surgery alone
After propensity score matching, 2028 patients were retained for the primary analysis
The NRD (National Readmissions Database) was the data source, covering years 2020–2022
Analyses incorporated NRD survey weights with Taylor series linearization to account for complex survey design
Results
The sensitivity analysis using E-values suggested the mortality benefit associated with MMA embolization is unlikely to be fully explained by unmeasured confounding.
E-value for the mortality association was 3.26
E-value for the upper bound of the 95% confidence interval was 1.63
E-values were calculated specifically to assess sensitivity to unmeasured confounding
What This Means
This research suggests that adding a procedure called middle meningeal artery (MMA) embolization to standard surgery for chronic subdural hematoma (a type of blood collection on the brain's surface) is linked to better short-term patient outcomes. Using a large national hospital database covering 2020–2022, researchers compared nearly 5,000 patients who either received surgery alone or surgery plus MMA embolization, which involves blocking a blood vessel that feeds the outer brain lining to reduce the chance of blood re-accumulating. After statistically matching patients to make the groups comparable, those who received the combined treatment had lower rates of being readmitted to the hospital within 30 days (8.8% vs. 11%) and lower in-hospital death rates (2.4% vs. 4.5%).
Patients who received MMA embolization were also much less likely to be readmitted specifically because the blood collection came back, with a 63% reduction in that type of readmission. The combined treatment did come with higher hospital costs, but patients did not stay in the hospital longer on average. The researchers also performed a statistical test to check whether hidden differences between the groups (factors not captured in the database) could explain the mortality difference, and found this was unlikely.
This research suggests that combining MMA embolization with surgery may offer meaningful benefits for patients with chronic subdural hematoma, particularly in reducing the risk of death and the need for return hospital visits. Because this is a database study and cannot prove cause and effect, the authors call for further prospective (forward-looking, controlled) studies to confirm these findings.
Al Saiegh F, Kotzur T, Tao E, Webb M, Mascitelli J, Seifi A. (2026). Adjunctive middle meningeal artery embolization is associated with lower 30-day readmission and mortality in chronic subdural hematoma: A propensity-matched national analysis.. Clinical neurology and neurosurgery. https://doi.org/10.1016/j.clineuro.2026.109514