Cerebral cavernous malformations

Durai arteriovenous malformations (AVMs) are interesting lesions, which can present as diagnostic and therapeutic challenges. Such AVMs were initially described as located solely in the durai venous sinuses, but during the last decade researchers have discovered them in other locations such as the tentorium and foramen magnum. It is understandable that they can develop in other locations because numerous arteriovenous shunts normally occur all over the dura. Early reports emphasize that they are congenital; however, some investigators have proposed that they are acquired lesions arising after sinus thrombosis and trauma. They also have variable clinical features. From 1975 to 2000 we treated 400 AVMs, of which 46 were dural. Of these 46 durai AVMs, 18 could be classified as skull base AVMs. We restricted the designation of skull base AVMs to those AVMs located in the tentorium or adjacent to bones of the skull base. Two of these AVMs actually had their vascular nidus located in the bone. The common durai sinus AVMs were excluded from this category. The presenting clinical features of these skull base AVMs ranged from headache and pulsatile tinnitus to intracranial hemorrhage. They were treated by a combination of endovascular and microsurgical treatment. The majority of patients had a good clinical outcome. Skull base durai A VMs are an interesting clinical entity. Their clinical course, treatment and final outcome are variable depending on their location. They should be managed by a multidisciplinary approach. [Neural Res 2003; 25: 860-864]

Keywords: Skull base; durai AVMs; tentorium

INTRODUCTION

Dural arteriovenous malformations (AVMs) are abnormal shunts located within the leaflets of dura matter. Such AVMs were initially described within the durai sheaths of venous sinuses1-3; however, it was subsequently discovered that they can be found in the tentorium as well as basal dura4,5. Aminoff classified durai AVMs into a posterosuperior group which drained into sagittal, transverse, or sigmoid sinus and an anteroinferior group with venous drainage into cavernous, petrosal, or sphenoparietal sinus. This anteroinferior group localized along the skull base is the focus of our present study. These skull base durai AVMs constitute 25% to 30% of all durai AVMs6. The majority of durai AVMs belong to the posterosuperior group occurring in association with transverse-sigmoid sinus, and they are excluded from the present series.

During the last 25 years (1975-2000), we have treated 400 cases of AVM at our institution, of which 46 were dural. Of these 46 durai AVMs, 18 could be classified as skull base AVMs. We can further subdivide the latter group into durai AVMs of the anterior cranial fossa (ACF), durai AVMs of the cavernous sinus and middle cranial fossa (MCF), and durai AVMs of the tentorium and posterior cranial fossa (PCF). Two of the durai AVMs located in the posterior fossa were unusual in that actual AVM nidus was situated in the bone though the venous drainage was via intracranial durai venous sinuses.

MATERIALS AND METHODS

Dural AVMs of ACF

Case 1

A 74-year-old male presented with visual deterioration. The AVM was located in the right ACF and cribiform plate. It was supplied by branches of the middle meningeal and internal maxillary arteries (Figure 1). The venous drainage was to the superior sagittal sinus. The AVM was treated by surgical excision after partial embolization. The patient had no complications.

Dural AVMs of the Cavernous Sinus and MCF

Case 2

A 54-year-old male presented with left proptosis and diplopia. Examination revealed ocular bruit and obscured disc margins. The AVM was located in the left cavernous sinus and supplied by branches of the dorsal meningeal, both internal carotids, ascending pharyngeal, internal maxillary, and middle meningeal arteries (Figure 2). The venous drainage was retrograde into left superior ophthalmic veins. The AVM was treated by endovascular embolization with subtotal occlusion and reduction of proptosis. Against medical advice, the patient left before treatment could be completed.

Case 3

A 30-year-old female presented with headache and nausea. The AVM was located in the right cavernous sinus with arterial supply from the internal carotid artery and venous drainage into the cavernous sinus and superior ophthalmic vein. The patient's progress is being followed.

Case 4

A 64-year-old female presented with headache, trigeminal facial pain, tinnitus, and diplopia. The AVM nidus was in the cavernous sinus and supplied by the internal carotid artery. The AVM underwent spontaneous thrombosis while under observation.

Case 5

A 74-year-old female presented with left eye chemosis, proptosis, and glaucoma. The AVM was located in the left cavernous sinus and supplied by both external carotid arteries and some Iwigs from the internal carotid artery. The venous drainage was via the superior ophthalmic vein. The patient required embolization twice and has been stable since 1997.

Case 6

A 65-year-old male presented with right eye proptosis, chemosis, and retro-orbital pain. The AVM was supplied by branches of the external carotid, ascending pharyngeal, and internal maxillary arteries. The venous drainage was retrograde into the superior ophthalmic vein and facial veins. The AVM was treated by transarterial embolization. After a year, the AVM recanulated, but the patient has been followed without any further treatment since the symptoms are minimal.

Case 7

A 30-year-old female presented with right eye chemosis, decreasing vision, and headache. The AVM nidus was in the right cavernous sinus and supplied by external and some internal carotid branches. Venous drainage was retrograde into the superior ophthalmic and facial veins. The AVM was treated by transvenous and transarterial embolization.

Case 8

A 61-year-old female presented with retro-orbital pain and diplopia. She had a bilateral cavernous sinus fistula supplied by branches of the internal maxillary, occipital, ophthalmic, and ascending pharyngeal arteries. The venous drainage was in the bilateral cavernous sinuses, right sphenoparietal sinus, superior sagittal sinus, and right inferior petrosal sinus. The AVM was treated by staged embolization. The patient did well but has right 6th, 10th and 12th nerve paresis.

Case 9

A 69-year-old male was referred to us with the incidental finding of middle fossa AVM located along the right petrous bone. The AVM was supplied by the middle meningeal, posterior meningeal and meningohypophyseal arteries and it drained into the right cerebral cortical veins and right petrosal sinus. The patient is being followed expectantly.

Dural AVMs of the PCF and tentorium

Case 10

A 63-year-old male presented with right anterior temporal lobe hematoma. The AVM nidus was located in the tentorial incisura and supplied by branches of external and internal carotid arteries. The venous drainage was via the leptomeningeal veins to the anterior temporal lobe and basal vein of Rosenthal with an associated venous aneurysm. The lesion was surgically excised with excellent results.

Case 11

A 49-year-old male presented with left hemifacial spasm. The AVM was located in the tentorium and petrous ridge and supplied by the middle meningeal artery, AICA, meningeal branch of PICA, and cavernous carotid arteries. It drained into the superior petrosal sinus and perimesencephalic veins as well as via the cortical venous branch to the transverse sinus with a venous aneurysm. The patient underwent pre-operative embolization followed by surgical excision. Post-operatively, he had deafness in the left ear, though hemifacial spasm disappeared with good facial function.

Case 12

A 29-year-old male presented with subarachnoid hemorrhage and had persistent hiccups. The AVM was located at the foramen magnum, supplied by the right vertebral and external carotid arteries, and drained into the basal and clivai veins. It was treated by surgical excision. Post-operatively, the hiccups persisted which were treated by bilateral phrenic nerve crush.

Case 13

A 65-year-old male presented with left trigeminal neuropathy and face and arm numbness. The AVM was located in the left petrous apex and tentorium, and supplied by middle meningeal artery, the tentorial branch of the internal carotid artery, and meningeal branches of the AICA and SCA. Venous drainage was into the lateral mesencephalic and internal cerebral veins. The AVM was treated by surgical excision. The resection was incomplete, and the patient had postoperative hemorrhage and expired.

Case 14

A 43-year-old female presented with headache, tinnitus, and bruit. The AVM was located around the right jugular foramen and supplied by vertebral, occipital, ascending pharyngeal, and posterior auricular arteries (Figure 3). It drained into the internal jugular vein, epidural venous plexus, and deep cervical and ascending cervical veins. The AVM was treated by embolization and then by surgical excision, lntraoperatively, the AVM nidus was found in the skull. The patient had an excellent outcome.

Case 15

A 30-year-old male presented with hemorrhage and focal seizures. The AVM nidus was located in the tentorium, and supplied by branches of the external carotid, posterior auricular, ascending pharyngeal, middle meningeal, occipital, vertebral, anterior-inferior cerebellar, and ophthalmic arteries. Venous drainage was into the superior ophthalmic and cortical veins with aneurysmal dilatation. The AVM was treated by embolization followed by surgical excision. The outcome was excellent.

Case 16

A 63-year-old male presented with SAH causing coma. The AVM was located around the foramen magnum and CP angle, and supplied by the right external carotid, occipital, and ascending pharyngeal arteries. Venous drainage occurred in the right transverse sinus, basal vein of Rosenthal and the internal cerebral vein, and was treated surgically following embolization. Post-operatively, the patient had intermittent difficulty with swallowing.

Case 17

A 55-year-old male was incidentally found to have a right tentorial AVM supplied by the occipital, middle meningeal, and meningohypophyseal arteries. Venous drainage was into the sphenoparietal sinus, cavernous sinus, basal vein of Rosenthal, and superior sagittal sinus. The patient refused treatment.

Case 18

A 48-year-old male presented with headache and tinnitus. The AVM was located in the left retromastoid area supplied by the left occipital, posterior auricular, middle meningeal, meningohypophyseal, and vertebral arteries. It drained into the internal and external jugular veins. The AVM was treated by surgical excision, lntraoperatively, the AVM nidus was found to be intraosseous. The outcome was excellent.

DISCUSSION

The concept of durai AVM was introduced in 1951 by Fincher7, and since then an increasing number of patients have been discovered with this condition. The last major review published in 19906 cited the total number reported in the literature as being 377. The pathogenesis of these lesions has been controversial. Initially, they were reported as being congenital entities1, but recently other investigators have proposed3,8 that they are acquired lesions developing after sinus thrombosis and trauma. Still, most agree that normally there are physiological arteriovenous fistulas in the dura, which may increase in size secondary to thrombosis or traumatic disruption.

Dural AVMs were initially described in association with durai venous sinuses, but they have been found in other locations as well. Our current study focuses on the extra sinusal lesions that are located along the skull base. In our experience, these skull based AVMs represented 40% of the durai AVMs. Our patients were predominantly male and ages ranged from 29 to 74, with a peak incidence of AVM seen in the 7th decade. We divided our cases into three subgroups, depending on location in either the anterior, middle, or posterior cranial fossa. The lesions in these three areas differ in presentation and clinical management.

Dural AVMs in the ACF are the least common6, and only one patient in our series belonged to this category. These patients, however, have a more aggressive course and are more likely to bleed. Treatment is primarily surgical with or without embolization.

The majority of durai AVMs in the middle fossa occur in association with cavernous sinus. We included only spontaneously occurring AVMs (types B, C, and D), excluding traumatic carotid cavernous fistulas (type A)9. These patients usually have an insidious onset and present with ocular manifestations such as chemosis, proptosis, and diplopia. Their clinical course is much more benign and many times they undergo spontaneous thrombosis. For this reason, patients with minimal symptoms can even be followed expectantly. Treatment, if needed, is via endovascular intervention. We have never undertaken open surgical excision of these lesions.

Tentorial and posterior fossa durai AVMs have an aggressive clinical course because a large percentage of these patients have cortical venous drainage predisposing to hemorrhage. Two of our cases in the posterior fossa also had an intraosseous nidus10 with the venous drainage being in the intracranial dural venous sinuses. The formation of intra-osseous AVMs is possible because the primary meningeal arteries that run on the endosteal surface of the dura give rise to a rich anastomotic network with communications with osseous and intracranial vascular networks11. Posterior fossa durai AVMs are usually treated with surgical excision, often following embolization.

CONCLUSION

Although skull base durai AVMs are uncommon, they represent a challenging clinical entity that requires a multimodality management approach.

REFERENCES

1 Aminoff MJ. Vascular anomalies in the intracranial dura matter. Brain 1973; 96: 601-612

2 Bitoh S, Hasegawa H, Fujiwara M, et al. Irradiation of spontaneous carotid-cavernous fistulas. Surg Neurol 1982; 17: 282-286

3 Chaudhary MY, Sachdev VP, Cho SH, et al. Durai arteriovenous malformation of the major venous sinuses: An acquired lesion. AJNR 1982; 3: 13-19

4 Pierot L, Chiras J, MederJF, ef a/. Durai arteriovenous fistulas of the posterior fossa draining into subarachnoid veins. AJNR 1992; 13: 315-323

5 Piske RL, Lasjaunias P. Extrasinusal durai arteriovenous malformations. Report of three cases. Neuroradiology 1988; 30: 426-432

6 Awad IA, Little JR. Durai arteriovenous malformations. In: Barrow DL, ed. lntracranial Vascular Maiformations. Park Ridge, IL: AANS, 1990: pp. 219-226

7 Fincher EF. Arteriovenous fistula between the middle meningeal artery and the greater petrosal sinus. Case report. Ann Surg 1951; 133: 886-888

8 Houser OW, Campbell JK, Campbell RJ, et al. Arteriovenous malformation affecting the transverse durai venous sinus - an acquired lesion. Mayo CHn Proc 1979; 54: 651-661

9 Barrow DL, Spector RH, Braun IF, et al. Classification and treatment of spontaneous carotid cavernous sinus fistulas. J Neurosurg 1 985; 62: 248-256

10 Malik GM, Mahmood A, Mehta BA. Durai arteriovenous malformations of the skull base with intraosseous vascular nidus. J Neurosurg 1994; 81: 620-623

11 Kerber CW, Newton TH. The macro- and microvasculature of the dura matter. Neuroradiology 1973; 6: 175-179

Asim Mahmood and Ghaus M. Malik

Department of Neurological Surgery, Henry Ford Hospital, Detroit, Ml, USA

Correspondence and reprint requests to: Dr Asim Mahmood, Department of Neurological Surgery, Henry Ford Hospital, 2799 W. Grand Blvd., Detroit, MI 48202, USA. [nsmah@neuro.hfh.edu] Accepted for publication July 2003.

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