Middle meningeal artery embolization for chronic subdural hematoma: Endovascular technique and radiographic findings

Abstract

Background and purpose Embolization of the middle meningeal artery (MMA) has recently been proposed as an alternative to surgery for treatment of chronic subdural hematoma (SDH), and several case reports have been published supporting its efficacy. It has been suggested that the primary pathologic process in chronic SDH is repeated microhemorrhaging into the subdural collection from fragile neovasculature within the SDH membrane that arises from distal branches of the MMA. Embolization could thus provide a means of eliminating this chronic rebleeding. Materials and methods Images were selected from MMA embolization procedures performed at our institution in order to illustrate the technique and theory behind its efficacy for treatment of chronic SDH. Results Images from MMA angiograms demonstrate the variability of MMA anatomy and help illustrate the importance of avoiding potential ophthalmic collaterals and branches supplying cranial nerves. The findings of irregular wispiness of the distal MMA vasculature, contrast outlining of the SDH membrane on angiography, and homogenous increased density within the SDH on postembolization head computed tomography are described. Conclusion MMA embolization may provide a safe alternative for treatment of chronic SDH, but careful angiographic assessment of MMA anatomy should be performed to avoid potential complications. The findings illustrated here lend support to the theory that the pathologic process of chronic SDH is repeated leakage of blood products from an inflamed, abnormal arterial neovasculature within the SDH membrane that arises from the MMA, and thus selective embolization could provide an effective treatment.

Keywords: Angiography; embolization; middle meningeal artery; minimally invasive; subdural hematoma.

Figures

Figure 1.

(a) Common configuration of the middle meningeal artery with a common trunk that divides into frontoparietal (1) and squamosal/temporal (2) branches. (b) With this configuration, embolization can be performed with the microcatheter tip proximal to the bifurcation of these branches to achieve embolization of the maximal amount of dura.

Figure 2.

(a) A prominent petrosal branch (asterisk) is identified coursing posteriorly within the petrous bone. The microcatheter tip (circled) is visible on both the subtracted (a) and unsubtracted (b) views past the take-off of this branch in order to avoid potential harm to cranial nerve VII.

Figure 3.

(a) An orbital branch is noted coursing anteriorly (asterisk). The microcatheter tip (circled) was navigated distally past this branch and great care was taken to avoid reflux of particles. (b) Postembolization angiogram shows reduced flow into the frontoparietal branch, but persistent supply of the dura over the posterior convexity. (c) The squamosal/temporal branch was selectively catheterized and again great care was taken to avoid reflux of particles. (d) Postembolization external carotid artery angiogram shows reduced flow into both frontoparietal and squamosal/temporal branches, but preserved, unchanged flow into the orbital branch.

Figure 4.

Lateral middle meningeal artery (MMA) angiograms ((a) and (b)) demonstrate a “cotton wool-like” appearance of the distal vasculature. (c) A zoomed-in example of the abnormal distal vasculature in another lateral MMA angiogram. Lateral projections of frontoparietal (d) and squamous temporal (e) MMA injections in another patient undergoing embolization for subdural hematoma. A “cotton wool-like” appearance is again demonstrated. Postembolization external carotid artery angiogram (f) shows a truncated MMA (circled) with minimal residual anterograde flow.

Figure 5.

Posteroranterior (PA) (a) and lateral (b) projections of a prolonged middle meningeal artery (MMA) microcatheter injection under blank fluoroscopic roadmap. Contrast pooling is observed within the distal MMA vasculature.

Figure 6.

Posteroranterior projections during contrast injection of the left middle meningeal artery (MMA), unsubtracted (a) and blank roadmap (b) views. Contrast appears to outline the subdural collection as the subdural hematoma membrane does, suggesting a vascular connection between this membrane and the MMA. A slice from the coronal computed tomography performed one day prior to this procedure is provided (c) to demonstrate the distribution of blood that is identical to the contrast outline in (b).

Figure 7.

(a) Pre- and (b) postembolization non-contrast head computed tomography scans on a patient who underwent right middle meningeal artery (MMA) embolization for a right-sided chronic subdural hematoma (SDH). There is a subtle but noticeable homogeneous increase in density within the subdural collection, suggesting the pooling of contrast from the procedure. This finding lends support to the theory of an arterial connection between the MMA and the membrane surrounding the SDH.