Rupture of a de novo dural AV fistula following adult cerebral AVM resection

Abstract

Acquired unruptured dural arteriovenous fistulas (DAVFs) have been described; however, ruptured de novo DAVFs remain exceedingly rare. We describe the case of a man in his 40s who presented with a recurrent intraparenchymal haemorrhage several years after angiographic cure of an intracranial arteriovenous malformation (AVM). Repeat angiography identified a new Cognard type IV DAVF anterior to the prior craniotomy. He underwent preoperative embolisation followed by craniotomy to completely obliterate the fistulous point. This case illustrates the need for close monitoring of AVM patients, even after complete obliteration, as local recrudescence of arteriovenous shunting can occur even in adulthood.

Background

Dural arteriovenous fistulas (DAVFs) represent a subset of intracranial arteriovenous malformations (AVMs) defined by having arterial supply from the extracranial dural arteries and early venous drainage into the intracranial sinuses or cortical veins. The aetiology of spontaneous DAVFs remains poorly understood; however, acquired de novo DAVFs have been observed after head trauma and a variety of intracranial procedures.^1–16 Although treatment of these iatrogenic DAVFs has been described, many were discovered incidentally or identified during follow-up for their primary pathology. None presented with rupture. As such, we report the first case of a de novo DAVF presenting with haemorrhage several years after complete resection of a ruptured AVM in an adult.

Case presentation

A 41-year-old man presented with right-sided weakness and numbness and was found to have a left frontoparietal intraparenchymal haemorrhage associated with an underlying cerebral AVM (figure 1). He underwent partial embolisation followed by craniotomy for resection and was found to have no residual AVM on follow-up angiography (figure 2). He recovered well with only mild residual right hemibody weakness and numbness.

Figure 1.

(A) Anteroposterior and (B) lateral left internal carotid artery angiogram demonstrating the presence of an arteriovenous malformation.

Figure 2.

(A) Anteroposterior and (B) lateral left internal carotid artery angiogram demonstrating complete obliteration of previously seen arteriovenous malformation.

Investigations

Four years later he presented with sudden onset headache, right-sided hemiplegia and mild aphasia and was found to have another left frontal intraparenchymal haemorrhage anterior to the prior AVM cavity (figure 3). Non-invasive imaging demonstrated a new aneurysmal dilation in the left frontal lobe that was not present on previous imaging after the AVM resection (figure 4). Angiography confirmed the presence of a new Cognard type IV DAVF with arterial supply from the right middle meningeal artery draining directly into a left frontal cortical vein (figure 5). There was no evidence of recurrent or residual AVM.

Figure 3.

CT demonstrating a left frontal intraparenchymal haemorrhage anterior to the prior resection cavity.

Figure 4.

(A) CT angiography demonstrating an aneurysmal dilation near the new left frontal haemorrhage (marked with a solid white arrow), (B) prior magnetic resonance angiography and (C) T2-weighted MRI following arteriovenous malformation resection with no evidence of aneurysmal dilation.

Figure 5.

(A) Left external carotid and (B) middle meningeal artery angiograms demonstrating fistulous connection to a left frontal cortical vein with an associated venous ectasia (marked with solid arrows).

Treatment

Transarterial embolisation of the fistula via the right middle meningeal artery was attempted but embolic material was unable to reach the fistulous point. As a result, the patient underwent craniotomy to ligate the fistula. Postoperative angiogram demonstrated complete obliteration of the fistula (figure 6).

Figure 6.

Left middle meningeal artery angiogram demonstrating complete obliteration of the fistula.

Outcome and follow-up

The patient had almost completely recovered 5.75 months after surgery except for a persistent right foot drop.

Discussion

A literature review was performed utilising the search terminology ‘iatrogenic intracranial dural arteriovenous fistula’. Only studies describing the development of a DAVF after an intracranial procedure were included. Fifteen studies met these inclusion criteria, and online supplemental table 1 displays the details of the 20 patients described in these studies. The average age of patients at the time of DAVF diagnosis was 46.1±26.4 years. The average time between their initial intracranial procedure and subsequent DAVF diagnosis was 13.2±12.9 months.^{1 3–16}

Some DAVFs were symptomatic with presentations including tinnitus, paresis, seizures, altered mentation, and difficulties with gait, memory or speech. In other cases, the DAVFs were asymptomatic and only identified on follow-up angiography for their original lesions. In all cases, the DAVFs were unruptured.^{1 3–16}

Treatments varied based on the vessels and types of flow involved.² In four cases, no treatment was performed as the venous drainage was contained within the dural venous sinuses or the lesion was deemed too small to require intervention.1 3 4 16 Most of the remaining patients were treated with embolisation. Eight required no additional treatment, while the rest received other therapies such as radiation or open surgical disconnection of the fistula.3–8 10 13–15 Two patients underwent open surgery alone for treatment of the DAVF.^{11 12} In one case, treatment was not reported.⁹

DAVFs are uncommon, representing only 10%–15% of all intracranial AVMs.¹⁵ Although the pathophysiology driving their development remains poorly understood, DAVF formation after head trauma and various intracranial procedures has been reported. Some have suggested that inadvertent venous thrombosis, whether post-traumatic or postsurgical, may result in venous hypertension that, in turn, promotes local angiogenesis which triggers the highly vascularised dura to recruit vessels that aberrantly connect to the vein distal to occlusion.³

Although a significant portion of DAVFs present with rupture, this has not been reported for de novo DAVFs discovered after an intracranial procedure despite 26% of these cases having cortical venous drainage. As such, we present the first case of a de novo DAVF presenting with an intraparenchymal haemorrhage several years after complete resection of a ruptured AVM in an adult. This discrepancy in the presentation of our patient may be attributed to the fact that he was lost to follow-up shortly after treatment of the original ruptured AVM. In the other cases, patients were typically followed closely with imaging for their initial pathologies, and when the DAVFs were discovered, they were treated promptly if they had any concerning features.^{1 3–16} Given that our patient had a Cognard type IV DAVF, even if it had not presented with haemorrhage we would have elected to treat it given the high risk of rupture in lesions with an AV shunt directly into a cortical vein.

Of the cases that required treatment, most received embolisation as a component of their treatment as this is often the preferred intervention for most DAVFs. However, if the fistulous point is not obliterated, craniotomy or radiosurgery can be performed to help obliterate the lesion.² In this case, we felt that transarterial embolisation would temporise the lesion but since the fistulous point was not occluded, the lesion would eventually recruit more arterial feeders over time. Although transvenous embolisation could have been attempted, we felt that the fistulous point was very distal and would require catheterisation of a significant portion of the superior sagittal sinus. Furthermore, given his sizeable haemorrhage and the tenuous nature of the cortical vein and associated venous ectasia, we felt surgical evacuation of the haematoma and obliteration of the fistula would be a more definitive treatment.

Although prior studies have suggested that both adult and paediatric AVMs can recur, to our knowledge, this is the first known case of a ruptured de novo DAVF occurring after complete obliteration of an adult intracranial AVM. The pathophysiology of AVM recurrence remains incompletely understood but many have suggested that local vascular endothelial growth factor expression and presence of unresected but previously embolised portions of the AVM may result in higher rates of recurrent disease.^17–21 Although the DAVF, in this case, could have simply developed after the craniotomy, given that the lesion was anterior to the prior surgery and there was unresected, embolised portions of the AVM, it is more likely that this contributed to recrudescence of AV shunting and resulted in the development of a de novo DAVF.

This case emphasises the need for rigorous, long-term follow-up care after resection of AVMs, even in adults, as there is still potential for recrudescence of abnormal arteriovenous connections over time despite having angiographic cure. Additionally, given the rarity of post-traumatic or postsurgical de novo DAVFs, long-term follow-up may provide more data on the incidence and prevalence of these lesions.

Learning points.

• De novo dural arteriovenous fistula (DAVF) development after an intracranial procedure is a relatively rare phenomenon.

• These lesions are frequently unruptured and discovered incidentally during follow-up.

• Symptomatic or high-risk de novo DAVFs should be treated while low-risk lesions can be monitored.

• The rupture of a de novo DAVF following previous obliteration of an adult cerebral arteriovenous malformation suggests that recrudescence of abnormal arteriovenous connections can still occur into adulthood even after angiographic cure.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).