Endovascular Treatment of Hemifacial Spasm Associated with a Petrosal DAVF Using Transarterial Onyx Embolization

Summary

This paper reports that decompression of the facial nerve by transarterial Onyx embolization may relieve hemifacial spasm (HFS) caused by dilated veins due to a right petrosal dural arteriovenous fistula (DAVF).

A 56-year-old man suffered severe chronic right HFS associated with a dilated right petrosal vein lying in the vicinity of the facial nerve.

The right petrosal DAVF was reached through the middle meningeal artery using a transfemoral arterial approach and was occluded with Onyx 18 (M.T.I.- ev3, Irvine, CA, USA). There was complete remission of HFS without recurrence after two months of follow-up.

This case supports vascular compression in the pathogenesis of HFS and suggests that facial nerve injury caused by a DAVF could be treated with transarterial Onyx embolization.

Introduction

Over the last 30 years an increasing volume of evidence has been presented to support a vascular compression aetiology of hemifacial spasm ^1-11. In these cases the facial nerve compression appeared to be the result of normal, tortuous, ectatic or redundant blood vessels ^1,2, aneurysm ³, arteriovenous malformation ^4-10, and dural arteriovenous fistula (DAVF) ¹¹. We describe a case of petrosal DAVF causing classical hemifacial spasm in a 56-year-old man followed by a complete relief of symptoms after transarterial Onyx embolization.

Case Report

A 56-year-old, right handed man presented in June 2011 with a six-year history of right-sided facial twitching. Initially only the external angle of the eye was involved but there was gradual spread and appearance of pulsatile tinnitus over the next five years to involve the rest of the right side of the face although the forehead and platysma were spared. Stressful situations increased both the intensity and frequency of the twitchings while periods of relaxation might be associated with a marked improvement. There were no other symptoms. The only abnormalities on examination were the features of right-sided clonic hemifacial spasm including a mild facial weakness. It was interesting to observe that over short periods of time the facial twitching was synchronous with the peripheral pulse rate. MRI images revealed irregular flow-void signals of dilated vessels adjacent to the root exit zone of the facial nerve (not showed). The right carotid artery angiography (Figure 1) displayed a complex petrosal DAVF on the right side. There were multiple arterial feeding vessels including the petrous branches of the right middle meningeal artery, the right meningohypophyseal trunk from the internal carotid artery and a small branch from the right posterior inferior cerebellar artery. The fistula drained into the right ecstatic petrosal venous system with flow into the infratentorial venous system and supratentorial venous system. Under general anesthesia, two 5F Envoy catheters were placed in the right common carotid artery and right vertebral artery. The anterior side was used for catheterization of the fistula, and the other was used for interim control angiogram. The right middle meningeal artery posterior branch was catheterized with a Marathon (ev3, Irvine, CA, USA) microcatheter was advanced close to the fistula site with the aid of Silverspeed 10 (ev3 Irvine, CA, USA). The microcatheter was flushed first with 3 ml of normal saline, and then with 0.23 ml of dimethyl sulfoxide (DMSO) over 40 seconds, followed by 2.4 ml of Onyx 18 injection over 25 minutes. The Onyx was slowly and continuously injected with intermittent pauses from 20 to 45 seconds whenever reflux of Onyx was observed to the catheterized access vessel or when the Onyx started to penetrate into an unfavorable vessel (normal vessel, functional venous sinus, etc). Frequent interim angiograms of all potential circulations using a second diagnostic catheter were performed to monitor safe and progressive Onyx deposition. Special attention was paid to avoid the Onyx refluxing or penetrating into vital vessels such as an internal carotid artery or a venous sinus through feeders and anastomoses. The Onyx penetrated the fistula to the venous sinus and could be controlled to permit reflux into the multiple feeding arteries, to assure total occlusion without sacrificing the sinus. The microcatheter was retrieved with gentle traction. Post-embolization unsubtracted angiograms anteroposterior and lateral views demonstrated the cast of Onyx obliterating multiple feeders and the affected sinus (Figure 1C, D) and showed complete occlusion of the DAVF. No transient or permanent neurological or procedure related complications were encountered. Post-embolization the patient had a prompt improvement of the spasm. Two months later he was spasm-free with no abnormal neurological signs.

Figure 1.

Right internal carotid artery angiogram in lateral view (A) shows the right petrosal DAVF supplied from the meningohypophyseal trunk of the internal carotid artery. Right internal carotid artery angiogram in lateral view (B) shows the right petrosal DAVF supplied from the middle meningeal artery. Venous drainage is to the right petrosal vein with a venous ectasia compressing the facial nerve (arrow), then to the supratentorial and infratentorial venous systems. Post Onyx embolization unsubtracted angiograms in anteroposterior (C) and lateral (D) views demonstrate Onyx cast filling the vascular network of the fistula and show complete occlusion of DAVF.

Discussion

The pathogenesis of hemifacial spasm is usually arterial compression of the facial nerve at the root exit zone ¹. Hemifacial spasm is also associated with other pathological conditions such as cerebellar pontine tumors, AVMs or aneurysm (Table 1). Park et al. ¹ described 236 consecutive patients with hemifacial spasm underwent microvascular decompression. Based on the contributing factors, compression patterns were categorised into six different types including: loop (n = 11; 4.6%), arachnoid (n = 66; 27.9%), perforator (n = 58; 24.6%), branch (n = 18; 7.6%), sandwich (n = 28; 11.9%) and tandem (n = 52; 22.0%). The compression patterns were significantly correlated with the compressing vessels involved. Thirty-two (86.5%) of 37 lesions where the vertebral artery was the compressing vessel involved the tandem type. Anterior inferior cerebellar artery was the compressing vessel involved in 49 (84.5%) of 58 perforator type compressions, while posterior inferior cerebellar artery was the compressing vessel involved in eight (72.7%) of 11 loop type compressions. Nagata et al. ¹⁰ described eight cases of symptomatic hemifacial spasms and they had gross pathological lesions such as a tumor (one epidermoid, one neurinoma, and two meningiomas), vascular malformation (one medullary venous malformation and two arteriovenous malformations), and aneurysm.

Table 1.

Facial spasm caused by vascular malformations.

Study (ref. no.)	Year	No. of patients	Sex (F/M)	Age	Causes	Vascular malformations	Treatment	Follow- up	Outcome
Pierry et al. 7	1979	1	no	no	no	posterior fossa arteriovenous malformation	Surgery	no	no
Buettner et al. 6	1983	3	no	no	no	Vascular malformations	no	no	no
Jannetta 2	1984	1	no	no	Venule	no	Surgery	no	complete remission
Tokimura et al. 8	1988	1	F	47	PICA	cerebellar AVM	Surgery	2 months	complete remission
Milani et al. 9	1991	1	no	10	redundant loop arising from AICA or PICA	no	Surgery	promptly	complete remission
Nagata et al. 5	1991	1	M	66	dilated feeding artery	AVM in the cerebellopontine angle	Surgery	no	no
Nagata et al. 10	1992	8	no	no	Arterial, venous and mass compression	Four tumors, three AVMs, one aneuyrsm	Surgery	no	complete emission
Konan et al. 4	1999	1	M	35	dilated right lateral mesencephalic vein	left temporo- occipital AVM	Transvenous coil embolization	2.5 years	complete remission
Neimat et al. 3	2005	1	F		anteroinferior cerebellar artery aneurysm	AVM in the cerebellopontine angle	Surgery	no	substantial recovery
Deshmukh et al. 10	2006	1	M	50	compression by arterialized leptomeningeal veins	tentorial dural arteriovenous fistula	Surgery	promptly	complete remission
M, male; F, female; AICA, anterior inferior cerebellar artery; PICA, posterior inferior cerebellar artery; AVM, arteriovenous malformation.

Since Deshmukh et al. ¹¹ first described the association of hemifacial spasm with a tentorial DAVF in 2006, this is the second case of hemifacial spasm caused by a DAVF. In our patient the MRI scan was very suggestive of arteriovenous malformation and, therefore, it was logical to proceed to cerebral angiography. In the patient with classical hemifacial spasm and normal MRI scan (including contrast enhancement) further neuroradiological investigations may be inappropriate and the question of therapy remains. In the present case, cerebral angiography showed that the hemifacial spasm was not caused by the petrosal DAVF but the dilated petrosal vein of the DAVF, which had compressed and indented the facial nerve at the root exit zone.

In recent years, there have been several reports of transarterial embolization of DAVF using Onyx ^12-21 as the primary treatment. All reported excellent occlusion of the fistula due to improved penetration of the embolic material as well as fewer arterial catheterizations. On the other hand, because of the superb penetration of the Onyx, special attention has to be paid not to over-penetrate the Onyx into normal arteries or venous drainage. In this case, it was necessary to use two catheters because the right common carotid artery and vertebral artery angiograms documented the entire DAVF. In Onyx treatment of DAVF cases with multiple feeders, we use two catheters to monitor the whole extent of the DAVF during Onyx injection. One catheter is used for guiding a microcatheter and control angiogram, while the other is catheterized to another cerebral circulation system that supplies the DAVF for interim control angiograms. This technique can aid us in detecting unfavorable Onyx filling toward normal vessels through anastomosis ^12,18,21. For safe injection, anatomical analysis and assessment of the potential anastomosis and the supply to transcranial nerves is mandatory ^18,21.

Conclusion

This case supports vascular compression in the pathogenesis of HFS and suggests that facial nerve injury caused by a DAVF could be treated with transarterial Onyx embolization.