Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: A Review of Established and Emerging Embolic Agents

Abstract

Middle meningeal artery embolization is an increasingly common procedure involved in the treatment of chronic subdural hematoma (cSDH) that can be an adjuvant intervention or an alternative to traditional medical or surgical therapies. Our review aims to summarize the mechanism, properties, and available clinical data for current and investigative embolic agents used for the treatment of cSDH. Pubmed, Scopus, and clinicaltrials.gov were searched for relevant studies and ongoing trials that examine middle meningeal artery embolization for cSDH. Particle agents, liquid embolic agents, and coil embolization are the common classes of embolic materials used in clinical practice and in ongoing trials. These embolic agents are not only mechanical occlusive materials; they have unique properties that address the angiogenic and proinflammatory mechanisms that propagate and sustain cSDH. Particle agents, such as polyvinyl alcohol and Embosphere (tris‐acryl gelatin microspheres) have been the most commonly used embolic agents given the long‐term evidence base regarding efficacy and established safety record. Liquid embolic agents such as cyanoacrylate glues and copolymer agents such as Onyx, Squid, and PHIL are increasingly common in clinical settings due to improved visualization on imaging, durable embolization, and better control of distal embolization. Coil embolization is used in conjunction with other embolic agents or as monotherapy in the setting of dangerous middle meningeal artery anastomoses. There are several ongoing randomized clinical trials and prospective cohort studies that will clarify the safety, efficacy, and use cases of particle agents, liquid embolic agents, and coil embolization for the treatment of cSDH.

Preoperative middle meningeal artery embolization in the treatment of organized chronic subdural hematoma

“…Chronic subdural hematoma (CSDH) is becoming increasingly prevalent and stands as one of the most frequent conditions necessitating interventional or surgical treatment. Its incidence in the general population is approximately 14 per 100,000, rising to 17 per 100,000 in individuals older than 70 years [ 5 ]. On the other hand, OSDH is exceedingly rare, constituting only 0.5% to 2% of all SDH cases [ 3 ].…”

“…Middle meningeal artery embolization (MMAE) is an adjunctive therapy that treats the pathophysiology of CSDH through embolization of neovascular vessels with an embolic agent to interrupt the vascular supply to the hematoma [ 5 ]. Reduced reoperation rates have been shown to be consistent with endovascular treatment as a stand-alone treatment as well as adjunctive to surgical resection (reoperation rate 1.7%) compared with surgical treatment alone (reoperation rate 27.5%) in previous studies [ 5 ]. We report the case of a 61-year-old male patient with a history of chronic subdural hematoma in the left hemisphere, who underwent twist-drill craniostomy with ipsilateral recurrence in the form of organized subdural hematoma.…”

Middle meningeal artery embolization for chronic subdural hematoma: an effective treatment with a bright future

“…Corroborating trials are forthcoming and may provide additional strength to these results, particularly in the role of MMAE as a standalone cSDH treatment, as well as in patients with bilateral cSDH and in the setting of comorbid conditions such as patients requiring anticoagulation. Ongoing randomized multicenter trials 12 will assess these and other issues, as well as evaluating the efficacy of other embolization agents (table 1). There is still much to learn.…”

“…Select ongoing randomized trials of middle meningeal artery embolization for chronic subdural hematoma (adapted from Tudor et al12 ) …”

Occult middle meningeal artery to middle cerebral artery anastomosis associated with prior trauma

“…Notably, the choice of embolic material for MMA embolisation widely varies, and studies evaluating polyvinyl alcohol particles, ethylene-vinyl alcohol dissolved in dimethyl-sulfoxide (Onyx; Medtronic Neurovascular, Irvine, California, USA), ethylene vinyl alcohol copolymer with suspended micronised tantalum dissolved in dimethyl sulfoxide (Squid; Balt, Montmorency, France), PHIL liquid embolic (MicroVention, Aliso Viejo, California, USA), n-butyl cyanoacrylate (n-BCA) and endovascular coils with and without gelatin sponge, have all been described in the literature. 4 Meta-analysis comparing the choice of embolic for MMA embolisation has insufficient available data to reach a conclusion regarding efficacy differences between the agents. 5 …”