The Utility of Preoperative CT Angiography for Middle Meningeal Artery Embolization in Acute Epidural Hematoma

Abstract

Objective: Hematoma expansion in acute epidural hematomas occurred in 11.2%–32% of patients treated conservatively at initial presentation and required craniotomy. Middle meningeal artery (MMA) embolization has been reported to be effective in preventing hematoma expansion. We report a case of an asymptomatic acute epidural hematoma in which CTA was used to identify the source of bleeding. Embolization of the MMA was performed to prevent hematoma expansion.

Case Presentation: A 30-year-old male patient was admitted to the emergency department following a collision with a car while riding his motorcycle. The patient exhibited clear consciousness and no neurological deficits. A head CT scan revealed a right parietal and temporal bone fracture, and an acute epidural hematoma directly below the fracture site. The hematoma was small, and the patient was treated conservatively. Three hours later, a follow-up head CT scan revealed an enlarged hematoma. This hematoma was found near the transverse sinus. To identify the source of the bleeding, a CTA was performed, which revealed extravasation into the hematoma from an area distant from the transverse sinus. We performed embolization of the MMA. The postoperative course was good with no postoperative hematoma expansion.

Conclusion: CTA for acute epidural hematoma without neurological symptoms is a useful diagnostic tool that can identify patients at high risk for hematoma expansion. If the findings indicate the need for intervention, MMA embolization is a treatment option that may reduce the risk of hematoma expansion and craniotomy.

Introduction

Acute epidural hematomas manifest in 2.7%–4% of head injuries.¹⁾ The etiology of hematoma formation encompasses disruption of the middle meningeal artery (MMA), bleeding from the fracture site, and disruption of the venous sinus.²⁾ However, the most prevalent etiology is a disruption of the MMA.³⁾ Craniotomy is the preferred treatment option for cases with neurological symptoms resulting from hematoma, while conservative treatment is indicated for small hematomas and asymptomatic patients.¹⁾

Hematoma expansion has been documented in 11.2%–32% of patients treated conservatively at initial presentation, requiring craniotomy.^3–6) Although there have been reports of the efficacy of embolization of the MMA in preventing hematoma expansion in such cases,^3,7,8) not all cases result in hematoma expansion. Therefore, appropriate case selection is imperative. We report a case of an asymptomatic acute epidural hematoma in which CTA was used to identify the source of bleeding, and embolization of the MMA was performed to prevent hematoma expansion.

Case Presentation

A 30-year-old male patient was admitted to the emergency department following a collision with a car while riding a motorcycle. He had no past medical history and was not taking any prescribed medications. Upon admission to our hospital, the patient exhibited clear consciousness and no neurological deficits. A head CT scan revealed a right parietal bone fracture, traumatic subarachnoid hemorrhage in the right temporal lobe, and an acute epidural hematoma directly below the fracture site. The fracture extended along the lambdoid suture from the parietal bone to the mastoid part of the temporal bone (Fig. 1A). The hematoma was small, and the patient was treated conservatively (Fig. 1B). The patient was admitted to the intensive care unit and treated with antihypertensive therapy. Three hours later, a follow-up head CT scan revealed an enlarged hematoma (Fig. 1C). This hematoma was found near the transverse sinus. To identify the source of the bleeding, a CTA was performed, which revealed extravasation into the hematoma from an area distant from the transverse sinus in the early phase (Fig. 1D and 1F). The extravasation was enlarged in the delayed phase (Fig. 1E). The patient was asymptomatic 3 hours after the initial visit, and an MMA embolization was performed to prevent future expansion of the hematoma.

Fig. 1 (A) The fracture extended along the lambdoid suture from the parietal bone to the mastoid part of the temporal bone (black arrowhead). (B) Initial head CT imaging revealed the presence of an epidural hematoma in the right occipital region. (C) A subsequent CT scan, performed 3 hours later, demonstrated an enlargement of the hematoma. (D) CTA revealed extravasation (white arrowhead) from a region distant from the venous sinus in the early phase. The early phase was taken 1 second after the internal carotid artery at the C1 level of the cervical spine, which was contrasted. (E) CTA in the delayed phase showed enlargement of extravasation (white arrowhead). The delayed phase was taken 4 seconds after the early phase. (F) 3D reconstruction image of CTA showed extravasation (red dot) within the hematoma (green area), which was separated from the venous sinus

Endovascular surgery

The procedure was performed under general anesthesia, and a 7-F sheath was inserted through the right femoral artery. Thereafter, 3000 units of heparin were administered, and a 7-F Roadmaster (Goodman, Aichi, Japan) was guided to the origin of the right external carotid artery.

Subsequently, a 4.2-F FUBUKI (ASAHI INTECC, Aichi, Japan) was guided from the 7-F Roadmaster (Goodman) to the origin of the right MMA. The 1.3-F DeFrictor Nano (Medico’s Hirata, Osaka, Japan) was navigated with CHIKAI X 010 (ASAHI INTECC) into the posterior convexity branch of the right MMA. Angiography from the MMA showed multiple extravasations from the MMA posterior convexity branch (Fig. 2A–2D). The injection of 12.5% n-butyl-2-cyanoacrylate (NBCA) was administered from a 1.3-F DeFrictor Nano (Medico’s Hirata), and the occlusion of the vessel was subsequently confirmed (Fig. 2E–2G). We injected 12.5% NBCA and, without pausing, withdrew the catheter. Many refer to this as “the simple push technique.” Immediately after surgery, protamine was administered. Finally, cone-beam CT was performed to confirm the absence of hematoma enlargement (Fig. 2H). Postoperative deterioration of the traumatic subarachnoid hemorrhage in the right temporal lobe, as depicted on preoperative CT imaging, was not observed.

Fig. 2 (A) Angiography from the ECA showed extravasation (white arrowhead) from the posterior convexity branch of the MMA. (B) Slab maximum intensity projection image of rotational angiography showed extravasation (white arrowhead) from the MMA posterior convexity branch. (C) The microcatheter (black arrow) was guided to just before the bleeding source. (D) Angiography from the MMA posterior convexity branch showed extravasation (white arrowhead). (E) NBCA was injected into the affected area, and it subsequently leaked out of the MMA (white arrowhead). (F) X-ray image after the injection of NBCA revealed extravasation of NBCA in the parietal convexity region. (G) Postoperative angiography of the ECA showed occlusion of the MMA posterior convexity branch. (H) Cone-beam CT after the procedure showed NBCA (white arrowhead) within the hematoma. There was no hematoma expansion. ECA, external carotid artery; MMA, middle meningeal artery; NBCA, n-butyl-2-cyanoacrylate

Postoperative course

In the postoperative period, the patient exhibited no signs of hematoma expansion or neurological deterioration. Following the observation of adequate postoperative progress, the patient was discharged from the hospital on the 5th postoperative day. Follow-up head CT obtained at the 1- and 2-month postoperative time points revealed a reduction in the size of the hematoma (Fig. 3).

Fig. 3 (A) Postoperative head CT the day after surgery revealed no enlargement of the hematoma in comparison to the immediate postoperative image. (B) One-month postoperative head CT demonstrated a reduction in hematoma volume. (C) Hematoma resolution was observed on the 2-month postoperative head CT

Discussion

The efficacy of MMA embolization for the treatment of acute epidural hematoma has been documented in previous studies. Peres et al. reported that all patients with acute epidural hematoma who were not considered candidates for craniotomy at initial presentation underwent MMA embolization regardless of cerebral angiography findings, and no subsequent craniotomy was required.³⁾ Although this report did not document any complications associated with the procedure, it is important to note that complications can occur, particularly when occluding the proximal MMA.⁹⁾ This is due to the presence of arterial supply from the cranial nerves and dangerous anastomosis with the ophthalmic and internal carotid arteries.¹⁰⁾ If the MMA near the foramen spinosum is the bleeding source, craniotomy may be the 1st consideration as the hematoma is in the temporal region where brain herniation is likely to occur. Also, there is concern about complications related to neurotrophic branches and dangerous anastomosis during embolization.

It is important to note that the MMA may not be the source of bleeding in some cases. Therefore, preoperative identification of the source of bleeding is useful in determining the indication for MMA embolization. Suzuki et al. performed contrast-enhanced CT prior to embolization of the MMA in patients with contrast leakage within the hematoma and reported that all patients subsequently had no hematoma expansion.⁷⁾ Sugi et al. has designated the increase in Hounsfield units in the hematoma after contrast-enhanced CT as the “leakage sign,” and has reported that this finding affects the expansion of the hematoma.¹¹⁾ Therefore, prior contrast-enhanced CT may be useful in selecting cases at high risk for hematoma expansion. In this case, the hematoma and venous sinus were in close proximity, which suggested the possibility that the venous sinus was the origin of the bleeding. To accurately diagnose the source of the bleeding, we performed CTA. To the best of our knowledge, there have been no reports of preoperative CTA for acute epidural hematoma to identify the artery as the source of bleeding, which, in turn, supports MMA embolization. This may be especially useful in cases of hematoma with bleeding points near the venous sinus. In this case, CTA was performed at the time of follow-up CT. If CTA had been performed at the time of initial diagnosis, it may have allowed for earlier therapeutic intervention. If the patient does not have renal dysfunction or other risks associated with the use of contrast media, such as contrast media allergy, CTA may be performed at the time of diagnosis of epidural hematoma, and an MMA embolization procedure may be considered for patients with extravasation.

The embolization material utilized in this case was NBCA, while various embolization materials were employed in previous reports.³⁾ It was reported that no hematoma expansion was observed with any of these materials. The MMA has abundant collateral blood circulation,¹²⁾ and head trauma is often complicated by coagulation abnormalities.¹³⁾ Considering these factors, the use of NBCA for immediate hemostasis is reasonable when, as in this case, the bleeding source is peripheral to the MMA and the risk of using liquid embolic material is low. There are no reports on the use of heparin and its dosage during embolization, or the use of protamine postoperatively. We kept heparin use to a minimum to prevent hematoma growth and administered protamine promptly after embolization. While no previous reports exist, it is important to consider that intracranial hemorrhage may enlarge with heparin administration.

In cases of multiple cerebral contusions, intraparenchymal hemorrhage, and coagulation abnormalities, the 1st priority is to correct the coagulation abnormalities quickly by replacing coagulation factors. Systemic heparinization may increase intraparenchymal hemorrhage, and we should be cautious about whether to perform MMA embolization. MMA embolization is particularly useful in cases such as the present case, in which the main lesion is an epidural hematoma and other intraparenchymal hemorrhages are minor.

In previous reports, the procedure has been performed under both local and general anesthesia.^3,8) We chose general anesthesia because of the possibility that systemic heparinization would enlarge the hematoma and cause restlessness, making it difficult to continue the procedure.

Suzuki et al. reported a mean hematoma resolution time of approximately 20 days following embolization.⁷⁾ In the present case, the hematoma demonstrated a decrease at 1-month post-embolization CT, and complete resolution at 2-month post-embolization CT, aligning with the previously reported outcomes.

Conclusion

CTA for acute epidural hematoma without neurological symptoms is a useful diagnostic tool that can identify patients at high risk for hematoma expansion. If the findings indicate the need for intervention, MMA embolization is a treatment option that may reduce the risk of hematoma expansion and craniotomy.

Acknowledgments

We acknowledge the editorial services that provided help with the language in this paper.

Disclosure Statement

The authors declare that they have no conflicts of interest.

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