Augmentation of Ipsilateral Middle Meningeal Artery Embolization After Unilateral Chronic Subdural Hematoma Evacuation Using a Contralateral Approach: A Case Series of 26 Consecutive Patients.

Background and objectives: After surgical drainage of a chronic subdural hematoma (cSDH), middle meningeal artery (MMA) embolization aids in preventing the revascularization of the cSDH membranes at the capillary level and, in turn, reaccumulation. With the MMA circulation ipsilateral to the surgical side often being disrupted, there is recruitment of collaterals from the contralateral MMA tree to the ipsilateral cSDH membranes. The aim of this study was to demonstrate the ability of additive contralateral liquid embolic (LE) injection after ipsilateral surgery to augment MMA embolization. We hypothesized that contralateral LE injection may provide additional MMA embolization to the affected ipsilateral side and increase response to treatment.

Methods: Consecutive cases of unilateral cSDH surgery with ipsilateral MMA embolization and additive contralateral LE injection were retrospectively identified from a prospectively maintained database of the senior authors.

Results: Over the study period, 26 consecutive cases of recurrent cSDH after unilateral surgery were identified. There was an average age of 73 ± 2.7 years (range 27-90 years), and 14 patients (54%) were female. All 26 patients (100%) had previous burr holes or a craniotomy. The average cSDH thickness after surgery and before embolization was 10 ± 0.3 mm, and the average midline shift was 3.5 ± 0.7 mm. Of the 26 patients who underwent bilateral MMA embolization, 96% had over-the-top contralateral-to-ipsilateral LE injection and penetration, providing additional embolization to membranes of the index ipsilateral cSDH. The average cSDH thickness on follow-up was 4 ± 5 mm and midline shift of 0.2 ± 0.7 mm. Complete cSDH resolution was achieved in 7 patients (39%). Two patients had cSDH recurrence, one of which required reoperation. There were no LE or catheter-related complications.

Conclusion: Contralateral MMA embolization in patients who have undergone ipsilateral cSDH evacuation and traditional ipsilateral MMA embolization allows for over-the-top LE penetration of cSDH membranes, thereby further augmenting the desired ipsilateral MMA embolization.