Middle meningeal artery embolization for recurrent subdural hematoma in an extra-intracranial anastomosis patient on anticoagulant medication: A case report

Introduction

With an incidence of 8.2 to 14.0 per 100,000 person-years, symptomatic chronic subdural hematoma (cSDH) is one of the most frequent neurological diseases. ¹ The most common reasons for recurrence are hematoma membranes, bilateral hematomas, postoperative subdural air collection, and increased tendency for bleeding. ² The recurrence risk remains high and is described in the literature as 0.3% to 33%. ³ Recently, the TOSCAN trial reported in a post hoc analysis that subgaleal drainage has a superior risk profile at similar efficacy as compared to subdural drainage. ⁴ Recent data postulate a low recurrence rate following endovascular MMA embolization in selected patients with cSDH. ⁵

MMA embolization, however, has been considered contraindicated in patients with extra-intracranial anastomoses due to an increased risk of cerebral ischemia.

The aim of this case report is to share our experience with MMA embolization in difficult vascular anatomy with recurrent subdural hematoma (SDH).

Case

A 67-year-old male presented with a right-sided cSDH (depth 42 mm) and a consecutive midline shift (MLS) of 15 mm (Figure 1). The patient had a past medical history of internal carotid artery (ICA) occlusion, ipsilateral middle cerebral artery (MCA) territory stroke, metabolic syndrome, type II diabetes, hypertension, and recently received coronary stenting. Therefore, he was on an oral P2Y12-antagonist. He presented with a worsening of his preexisting hemiparesis on the left side at the neurosurgical outpatient clinic of the University Hospital Innsbruck in 2022. Furthermore, he reported headaches and dizziness for several days. The P2Y12-antagonist (clopidogrel) was paused and bridged with enoxaparin therapy. The patient was treated with a burr hole and the insertion of a subgaleal drainage with suction. The drainage remained under continuous negative pressure for three days according to our institutional standard.

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Figure 1.

Axial CT scans of the index patient illustrate the progression over time.

Four weeks later the patient presented for a planned follow up. The computed tomography (CT) scan showed a recurrence of the large SDH on the right side. The scan revealed a depth of 40 mm with chronic and acute components (Figure 1). The patient showed no new neurological symptoms, however, due to the recurrence of the cSDH with a comparable depth to the initial presentation, the patient was scheduled for revision surgery and a subdural drainage was inserted. Four weeks later the patient presented a second recurrence of the SDH upon CT (Figure 1).

Due to the sufficient drainage and the repeated recurrence of the cSDH, we considered MMA embolization. The patient had a known history of right-sided ICA occlusion with a slight cross-flow from the contralateral side via the anterior communicating artery and the hypoplastic right-sided A1 segments. The hematoma was then treated by endovascular particle embolization of the ventral and dorsal branches of the right-sided middle meningeal artery (MMA). Written informed consent has been obtained. In accordance with Austrian federal laws a formal ethics approval was waived because the presented manuscript represents a retrospective case report/series (Institutional Review Board/Ethics Committee approval: Protocol number 1227/2022).

For the intervention, a right-sided femoral arterial approach was used. Intra-interventionally, a pronounced collateral between the ventral branch of the right-sided MMA to the ophthalmic artery (and consecutively contrast in the MCA) was seen (Figure 1). Initially, the dorsal branch of the MMA was embolized with polyvinyl-alcohol particles of the size 150 to 250 µm (Contour PVA Embolization Particles, Boston Scientific, Marlborough, MA, USA). Then, the ventral branch of the MMA was approached with the same particle size. The embolization was, respectively, performed 2 cm distally to the anastomosis with no visible reflux during the intervention. No visual field or visual acuity alterations occurred. After embolization, the membranes of the SDH were no longer detectable (Figure 1). One day after embolization a magnetic resonance imaging scan was obtained. The scan showed no complications (Figure 1). Furthermore, no new neurological symptoms developed. The patient was discharged on post-interventional day two. The P2Y12-antagonist was still paused and bridged with enoxaparin therapy. Four weeks later the patient visited our outpatient clinic. The axial CT scan showed a stable SDH without recurrence of the MLS (Figure 1). He presented with a full recovery of the preoperative symptoms three months after intervention and no further intervention was needed (Figures 1 and 2).

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Figure 2.

Computed tomography (CT) angiography showing the medial meningeal artery on the right side before and after embolization.

Discussion

The incidence of cSDHs is increasing. Especially in the age group of 80 years or older, the incidence has almost tripled since 1990. Furthermore, the percentage of patients receiving anticoagulant or antiplatelet medication almost doubled. This was the conclusion of a retrospective study aiming to determine the population-based epidemiology of cSDH over a 26-year period.^6,7 A very recently published review of the current state of the art in treating cSDHs revealed that recurrence remains the main complication in up to 33%. The authors described that embolization can reduce the recurrence rate. ⁸

The pathophysiology behind the development of cSDH is still not entirely understood. The cause of cSDH is the oozing from bridging veins resulting in a hematoma in the space between the arachnoid and dura mater. However, the neovascularization and leaking from an outer membrane are thought to maintain this process. This supports the theory that the MMA is implicated in cSDH formation.^9,10

Shotar et al. ¹¹ described in 140 MMA cases the angiographic anatomy of the MMA in relation to cSDH embolization. In their study, an angiographic relationship between the MMA and the ophthalmic artery was seen in 5% of the cases. However, in <1% of the orbital branches of the ophthalmic artery directly originated from the MMA. ¹¹

In this case report, we present the course of a 67-year-old male patient with an ICA occlusion, currently receiving P2Y12-antagonist treatment while developing a cSDH. The uniqueness of the case described above is that the angiography revealed the condition of a direct anastomosis between the ventral branch of the right-sided MMA to the ophthalmic artery due to the ICA occlusion in his past medical history. Successively, both branches were sufficiently embolized. After embolization, the patient remained stable without neurological deficits and no progression of the known cSDH or MLS occurred.

Shotar et al. ⁵ described in 2020 that postsurgical embolization of the MMA can reduce the recurrence rate of cSDH. A retrospective review in a multicenter setting showed in 151 cases that MMA embolization is a safe adjunctive therapeutic option in the elderly. ¹² Even in anatomical variations of the MMA orbital branches embolization can be a safe option. ¹¹

A single-center experience of 75 cases focusing on whether additional MMA embolization along with surgical evacuation showed that additional embolization reduces the frequency of recurrence of cSDH. ¹³

As society becomes progressively older and the past medical history of patients becomes more complex, the increasing incidence of cSDH will be a burden to patients and a future challenge for neurosurgeons. MMA embolization can be a suitable option for complex cases even in patients with acquired extra-intracranial anastomoses.

Conclusion

MMA embolization has been popularized recently for recurrent cSDH.

It is a potential option even in patients with extra-intracranial anastomosis.