Traumatic middle meningeal artery pseudoaneurysm: Case report and review of literature
Article information
Abstract
Traumatic aneurysms represent less than 1 percent of intracranial aneurysms and middle meningeal artery pseudoaneurysms are even rare. Traumatic aneurysms are usually pseudoaneurysms formed by the rupture of all the layers of the vessel wall. They are associated with high mortality as they can present as epidural, subdural, and rarely intraparenchymal hematoma. However, only nine cases of traumatic pseudoaneurysms of middle meningeal artery are reported that have presented as an acute intracerebral hematoma. We report a case of ruptured pseudo aneurysm of middle meningeal artery presenting with intraparenchymal hematoma in which hematoma evacuation and aneurysm excision was done immediately. The patient recovered well in the post-operative period. In addition, we reviewed all cases of middle meningeal artery pseudoaneurysms reported in the literature either as extradural hematomas, subdural/intraparenchymal hematomas, or subarachnoid hemorrhages. However, identifying the location of the aneurysm intraoperatively may be challenging as the hematoma may obscure the same. Distance from the sphenoid ridge may serve as a good intraoperative guide. Intraoperative localization along with surgical evacuation if done immediately can lead to gratifying results.
INTRODUCTION
Pseudoaneurysm develops when the vascular wall tears through all its layers, and the surrounding brain tissue forms the aneurysm’s wall. Middle meningeal artery pseudoaneurysms are rare entities [2] most commonly presenting as acute or delayed extradural hematoma following trauma [2]. They are life-threatening and are associated with skull base fractures in the temporal skull base. The natural history of these pseudoaneurysms is unpredictable with some cases showing spontaneous resolution and some showing rupture requiring surgical evacuation.
Management of these pseudoaneurysms can be done either surgically or with endovascular intervention. There is no defined standard consensus regarding the treatment for the same.
CASE DESCRIPTION
A 36-year-old male presented to emergency in an altered sensorium following a road traffic accident with a Glasgow coma scale of 10/15. A plain computed tomography (CT) of brain showed a right temporal hematoma of volume 40 cc with midline shift of 7 mm and effaced cisterns and small contusion in left temporal lobe with linear undisplaced fracture of the right temporal bone (Fig. 1A). The patient was planned for emergency evacuation of right temporal hematoma, and a CT angiography was done before shifting to the operation theatre. CT angiography showed the presence of a middle meningeal artery pseudoaneurysm with the nidus situated adjacent to the hematoma (Fig. 1B). The decision of hematoma evacuation along with aneurysm excision was made.
(A) CT Plain brain shows contusion in right temporal lobe with linear undisplaced fracture of the right temporal bone. (B) CT angiogram suggestive of right middle meningeal artery pseudoaneurysm. (C) Pseudoaneurysm located close to sphenoid ridge. (D) Excision of pseudoaneurysm along with the dural cuff. (E) Post-operative CT Brain shows good hematoma evacuation with opening of the basal cisterns. (F) Post-operative CT angiogram shows the absence any aneurysm. CT, computed tomography
The patient underwent right frontotemporal craniotomy and aneurysm was located 3 cm from the sphenoid ridge as calculated from the preoperative CT scan (Fig. 1C). There was associated fracture and underlying dural tear in line with the pseudoaneurysm, providing a pathway for the hematoma to extravasate into the temporal lobe. Apart from the pseudoaneurysm, no other source of bleeding was noted intraoperatively and the pseudo aneurysm was in contact with hematoma (Fig. 1C). Upon dislodging the clot brisk bleeding from the pseudo aneurysm was also noted which was controlled with coagulation on either ends of the middle meningeal artery close to the aneurysm followed by excision of the pseudo aneurysm (Fig. 1D). The dura was then repaired with temporal fascia graft and bone flap was replaced. The patient recovered well in the post-operative period with improvement in sensorium to Glasgow Coma Scale (GCS) 15/15. Histopathological study showed the presence of aneurysmal sac with tear lined by fibrin clot. The post-operative CT angiogram showed the absence of any aneurysm along with good hematoma evacuation and opening of the basal cisterns (Fig. 1E, 1F). He was discharged on post-operative day 2 and follow-up at 6 months showed complete recovery with a Glasgow outcome scale extended score of 8.
Literature review
We searched PubMed for the following terms: “pseudoaneurysm” AND “blunt head trauma”; “pseudoaneurysm of the middle meningeal artery in order to review the research. The search was restricted to humans and English-language articles. There was no limitation on the kind of publication, the date of publication, or the status of the publication. The search was expanded by carefully cross-checking all retrieved publications that matched the study’s objectives. The final search was conducted across all databases on September 15, 2024.
DISCUSSION
A total of 40 such cases of middle meningeal artery pseudoaneurysm are reported in the literature [1]. They must be differentiated from true aneurysms which are also quite rare and are often seen in high-flow states, like arteriovenous malformation, dural arteriovenous fistula, Paget’s disease, hypertension, meningioma, and Moyamoya disease [8]. Their pathophysiology and management are identical to aneurysms of the circle of Willis. Pseudoaneurysms are usually associated with skull base trauma leading to rupture of all the layers of the vessel wall but are lined by fibro-connective tissue surrounding a rent in the arterial wall without any normal arterial layer. Due to poor support in the arterial wall, they tend to progress fast with a rupture rate of as much as 20 percent [13]. They can result in a wide range of hematomas, with epidural ones being the most frequent.
The natural history of pseudoaneurysm is unclear, initially, there is a tiny tear in the vessel, and extravasation of blood is prevented by clot formation. This clot undergoes fibrous organization and is excavated by the flowing blood to form the sac of a false aneurysm. Thus, they typically manifest as a delayed cerebral hematoma with an abrupt clinical decline. The interval between trauma and aneurysmal rupture ranges from 1 to 30 days (mean 15 days) [1]. However, in our case, the pseudoaneurysm was noted in the first hours of trauma along with intracerebral hematoma. This is a rare entity with only nine such cases reported in the literature (Table 1). The exact mechanism of acute intraparenchymal hematoma along with a pseudoaneurysm is poorly understood. However, in these instances, it is likely that the arterial rent was significant and that the fresh clot from the acute traumatic hematoma quickly walled off to form the pseudoaneurysm. The associated dural tear could provide pathway for the bleeding to extravasate into underlying parenchyma resulting in intracerebral hemorrhage [6].
Acute pseudoaneurysm of middle meningeal rupture and contextual intraparenchymal hemorrhage
Pseudoaneurysms have varied presentations across the literature. Most commonly they present with extradural hematomas. Several such cases have been reported. These extradural hematomas are mostly temporal in location and are frequently associated with fractures. These hematomas when indicated are operated and pseudoaneurysms are excised at the same setting or at a later time with endovascular intervention. Intraoperative experience can at times be devastating from these pseudoaneurysms as noted in the study by Kim et al. [5] wherein they had to do a simultaneous angiogram intraoperatively to identify the source of torrential bleeding to find a pseudoaneurysm and bleeding was controlled only after embolization of this pseudoaneurysm. Some patients also present with a late appearance of pseudoaneurysm. Ko et al. [7] presented a rare case of the late appearance of pseudoaneurysm of the middle meningeal artery with arteriovenous fistula which was embolized successfully. A similar combination was found by Sicat et al. [15] in their case report. Pseudoaneurysms may have a gradually progressive course when observed, which can increase the chances of rupture, Lee et al. [10] reported two such cases where on follow-up, there was a significant increase in the size of pseudoaneurysms and both cases underwent embolization. On the contrary, Srinivasan et al. [16] described a case of spontaneous resolution of pseudoaneurysm within two weeks without any intervention. Kuramoto et al. [9] and Liliequist et al. [11] too demonstrated cases of spontaneous resolution of pseudoaneurysm without intervention.
A considerable number of cases have also been reported to have presented with a subdural hematoma and subarachnoid hemorrhage. They have a similar line of management. However, presentation as an acute intraparenchymal hematoma is a rare entity and is most commonly seen in temporal location. There has been a total of 9 such cases reported so far (Table 1). In all of these cases, the hematoma was large enough to cause a drop in GCS and warranted surgical evacuation. In most of these cases, hematoma evacuation and management of pseudoaneurysm were done in the same procedure either surgically or by embolization. In all these cases the presence of pseudoaneurysm was known pre-operatively. There are 2 case reports wherein a double approach was performed i.e. hematoma evacuation was done at initial presentation followed by digital subtraction angiography/CT angiography (DSA/CTA) and subsequent embolization of pseudoaneurysm. Intracerebral hematoma resulting from these pseudoaneurysms can be life-threatening and there have been two instances of death as reported by Bruneau et al. [1] and Markwalder et al. [12] In the case report by Markwalder et al. [12], there was the recollection of hematoma after evacuation and during re-exploration, there was torrential bleeding which necessitated the ligation of the carotid artery. Hence, the operating surgeon must be aware of such vascular pathologies and plan accordingly. There are few case reports of delayed intracranial bleed due to these pseudoaneurysms occurring days to months following head trauma. The delayed presentation may vary from as early as 7 days to 11 months across the literature. However, most of the cases occurred within 30 days of trauma. All these cases had an intracranial injury at presentation but were not severe and were managed medically. All these cases had neurological deterioration at a later date with new-onset intracranial bleeding and all these cases required surgical evacuation and excision/embolization of pseudoaneurysm. Most of them had bad outcomes, with 2 reported deaths and 2 with severe morbidity. Therefore, there should be a suspicion of pseudoaneurysm rupture in patients presenting with delayed/ new onset intracranial bleeding following trauma.
CT angiography serves as an excellent tool in diagnosing and localizing the pseudoaneurysm. It can be done along with regular imaging for trauma when there is the presence of intracranial hematoma with skull fractures. The sphenoid ridge serves as excellent landmark, calculating distance of the pseudo aneurysm from it is extremely beneficial in locating the pseudo aneurysm intraoperatively as was done in our case. The overlying hematoma often obscures the aneurysm and manipulating without an idea about its location may lead to torrential bleeding. Additional information about the pseudoaneurysm can be obtained from DSA. These pseudoaneurysms on DSA show specific characteristics - they are found at a distance from the branching point without any evidence of neck. They have delayed filling and emptying so that the contrast medium has time to settle at the bottom of the aneurysm. Hence these aneurysms are often seen in the late injection stages of selective external carotid angiography [3].
As these pseudoaneurysms can culminant in fatal ruptures it is essential to treat them when diagnosed either incidentally or following a trauma. Both surgical and endovascular options are available. In an acute event that is associated with intracranial hematoma, craniotomy with evacuation of hematoma together with excision of pseudoaneurysm is an excellent option, which can be executed even in small centres and is time-saving and an economically feasible option. For those presenting incidentally or with insignificant intracranial hematoma, endovascular management can be considered. Traumatic pseudoaneurysms can be effectively treated using a variety of endovascular methods, such as coiling, liquid embolization, and stenting [4].
CONCLUSIONS
Middle meningeal artery pseudoaneurysms are a rare occurrence, they should be taken into account in certain circumstances, particularly when there is sudden neurological decline that occurs days or weeks after a cranial trauma and when there is a spontaneous subdural or extradural hemorrhage. They also need to be kept as a differential diagnosis of intracerebral hematoma, especially when associated with skull fractures. Surgical excision followed by hematoma evacuation at the same procedure may be a better option than endovascular intervention followed by surgical evacuation.
Notes
Disclosure
The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.