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Spontaneous arteriovenous fistula of the orbit: case report
Surgical Neurology 65 (2006) 55 – 57 www.surgicalneurology-online.com
Technique
Spontaneous arteriovenous fistula of the orbit: case report Jun-ichiro Hamada, MD, PhDT, Motohiro Morioka, MD, PhD, Yutaka Kai, MD, PhD, Tomotaka Sakurama, MD, Jun-ichi Kuratsu, MD, PhD Department of Neurosurgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-856, Japan Received 14 February 2005; accepted 31 March 2005
Abstract
Background: A spontaneous arteriovenous fistula of the orbit is exceedingly rare. We report the first case of such condition treated with direct surgical exposure of the superior ophthalmic vein (SOV) followed by embolization. Case Description: A 55-year-old man presented with upper lid swelling, conjunctival chemosis, and proptosis of the right eye. Angiography revealed an intraorbital shunt supplied by the ophthalmic artery whose venous drainage curved anteriorly to the SOV. Because transarterial and transvenous endovascular approaches to treat the fistula were impossible, we performed direct surgical exposure of the SOV followed by the embolization of the fistula. Postoperative angiograms demonstrated complete closure of the fistula. All symptoms had disappeared by 2 months after surgery. Conclusions: For appropriate treatment planning, it is necessary to identify the location of the shunt. In cases where transarterial and transvenous endovascular approaches to treat the fistula are difficult or impossible, direct surgical exposure of the SOV followed by embolization may accomplish complete closure of the fistula without significant risk for iatrogenic injury. D 2006 Elsevier Inc. All rights reserved.
Keywords:
Arteriovenous fistula; Ophthalmic artery; Orbit; Superior ophthalmic vein
1. Introduction
2. Case report
Arteriovenous fistulas (AVFs) in the orbit are quite rare, and most are part of facial arteriovenous malformations [1-5,7]. Arteriovenous fistulas develop from a single communication between an artery and a vein. Because the bypass of capillary beds results in decreased vascular resistance, regional blood flows preferentially through the fistula, thereby exposing the veins to increased intraluminal pressure. Successful treatment requires closure of the fistulas. We report clinical and radiological findings in a patient with a spontaneous AVF in the orbit. We discuss our experience with this patient and present an effective management strategy for similar cases.
2.1. History
T Corresponding author. Tel.: +81 96 373 5219; fax: +81 96 371 8064. E-mail address: [email protected] (J.-i. Hamada). 0090-3019/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2005.03.043
This 55-year-old man presented with a 6-month history of upper lid swelling, conjunctival chemosis, and proptosis of the right eye. There was no history of orbital trauma or family history of vascular disorders. 2.2. Examination and operation On admission, ophthalmologic examination disclosed marked dilatation of conjunctival vessels, chemosis, and exophthalmos of the right eye. Ocular movements were almost normal. Intraocular pressure was 22 mm Hg in the right eye and 10 mm Hg in the left eye. Neurologic examination showed no other deficits. Magnetic resonance imaging disclosed right exophthalmos, extraocular muscle enlargement, and a dilated superior ophthalmic vein (SOV) (Fig. 1). Early-phase angiograms revealed an enlarged abnormal branch of the ophthalmic artery that supplied the SOV after an abrupt change in its vascular caliber and
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because of fracture of the ethomoid bone with subsequent rupture of the artery into the ophthalmic venous system [4,6], the orbital AVF in our patient occurred spontaneously without trauma. The hemodynamic characteristics of AVFs in the orbit are comparable to those of orbital arteriovenous malformations or carotid-cavernous sinus fistulas. Increased
Fig. 1. T2-weighted magnetic resonance images showing right exophthalmos, extraocular muscle enlargement, and a dilated SOV (arrow).
course. The SOV drained anteriorly into several small tributaries with slow outflow (Fig. 2). No nidus and no draining into the cavernous sinus were observed. These findings were compatible with the diagnosis of AVF in the orbit. The feeding artery from the ophthalmic artery could not be subjected to arterial embolization. Because tributaries from the SOV also failed to provide access to treat the fistula (because their small size prevented cannulation necessary for embolization), we used the transcranial extradural approach. Opening the roof of the orbit and laterally retracting the superior rectus muscle revealed a dilated SOV. After interruption of this vein, intraoperative angiograms did not show complete disappearance of the fistula. Therefore, rectangular pieces of oxidized cellulose (Surgicel), about 2 2 3 mm, were inserted through the SOV. This packing of the SOV resulted in complete obliteration of the fistula on the intraoperative angiograms. 2.3. Postoperative course Although he experienced transient mild abducens palsy that resolved completely by the third week after surgery, his symptoms had disappeared by the second postoperative month. Angiograms obtained 6 months after surgery demonstrated the occlusion of the fistula, and he experienced no symptom recurrence (Fig. 3). 3. Discussion Arteriovenous malformations are congenital lesions with numerous, large feeding arteries, a central nidus, and many dilated draining veins. Arteriovenous fistulas, on the other hand, are characterized by a single arteriovenous connection within the vascular mass [2]. Although most AVFs in the orbit occur after injury to an ethomoid artery
Fig. 2. A: Superselective angiograms of the right ophthalmic artery demonstrating that a branch from the ophthalmic artery supplies the AVF. B: Venous drainage curved anteriorly to the SOV. The arrow indicates the location of the fistula. C: The SOV drained into several small tributaries with slow outflow.
J.-i. Hamada et al. / Surgical Neurology 65 (2006) 55–57
57
References [1] Chakrabortty S, Nagashima T, Izawa I, et al. Intraorbital arteriovenous malformation: case report. Surg Neurol 1993;40:320 - 5. [2] Hayes BH, Shore JW, Westfall CT, et al. Management of orbital and periorbital arteriovenous malformation. Ophthalmic Surg 1995;26: 145 - 52. [3] Kim JW, Stewart WB, Spencer WH, et al. Acute expansion of an orbital vascular malformation. Arch Ophthalmol 1999;117:844 - 5. [4] Kupersmith MJ. Neurovascular neuro-ophthalmology. Berlin7 SpringerVerlag; 1993. p. 69 - 108. [5] Ohtsuka K, Hashimoto M. Clinical findings in a patient with spontaneous arteriovenous fistulas of the orbit. Am J Ophthalmol 1999;127:736 - 7. [6] Trout HH, McAlister HA, Giordano JM, et al. Vascular malformations. Surgery 1985;97:36 - 41. [7] Wright JE. Orbital vascular anomalies. Trans Am Acad Ophthalmol Otolaryngol 1974;78:606 - 16. Fig. 3. Angiograms obtained 6 months after surgery show complete closure of the fistula.
Commentary venous pressure in the orbit and signs of orbital congestion, such as proptosis, dilation of conjunctival and retinal vessels, ocular hypertension, and dilation of the superior and inferior ophthalmic veins, can be found. Orbital symptoms are frequently related not only to the degree of shunt but also to the adequacy of external drainage of the SOV. Very slow flow shunts can result in severe proptosis and chemosis because of poor or nonexistent external drainage. Angiographically, AVFs are characterized by a single arteriovenous connection within the vascular mass. Abrupt changes in the vascular caliber and/or the course of the feeding pedicle mark the location of the shunt between the artery and vein. Proximal ligation of feeding arteries is inadequate because of the potential for retrograde flow and recruitment of collateral vessels. Therefore, successful treatment requires closure of the fistulas. We performed direct surgical exposure of the SOV and embolization with rectangular pieces of oxidized cellulose because transarterial and transvenous endovascular approaches to treat the fistula were impossible. If transvenous occlusion is to be performed, the site of embolization should be as close as possible to the fistula to prevent recruitment of collateral veins for drainage. Arteriovenous fistulas of the orbit must be considered in the differential diagnosis of carotid-cavernous sinus fistulas and arteriovenous malformations. In our case, where transarterial and transvenous endovascular approaches to treat the fistula were limited, direct surgical exposure of the SOV followed by embolization accomplished complete closure of the fistula without significant risk for iatrogenic injury.
Orbital vascular malformations are relatively rare. A well-known example is Wyburn-Mason syndrome, which consists of retinal and cerebral AVM, particularly along the optic pathways [1,2]. On the other hand, AVFs are usually traumatic in origin, and spontaneous forms, as reported here, seem extremely rare. The choice of treatment of AVF is obliteration of the fistulous point, approached from either arterial or venous side. The case reported here seems exceptional because dilated SOV diverged into several small tributaries, which makes the transvenous approach from the skin extremely difficult. Superior ophthalmic vein did not drain into cavernous sinus either. The authors thus used direct surgical exposure of SOV and packed (embolized) the fistulous point, rather than direct coagulation. This would indeed be less invasive if the fistulous point is located deep in the orbit. This case report demonstrated an alternative method in difficult cases for embolization. Nobutaka Kawahara, MD, PhD Department of Neurosurgery Graduate School of Medicine University of Tokyo Tokyo 113-8655, Japan References [1] Chan WM, Yip NK, Lam DS. Wyburn-Mason syndrome. Neurology 2004;62:99. [2] Ponce FA, Han PP, Spetzler RF, Canady A, Feiz-Erfan I. Associated arteriovenous malformation of the orbit and brain: a case of WyburnMason syndrome without retinal involvement. Case report. J Neurosurg 2001;95:346 - 9.
Technique
Spontaneous arteriovenous fistula of the orbit: case report Jun-ichiro Hamada, MD, PhDT, Motohiro Morioka, MD, PhD, Yutaka Kai, MD, PhD, Tomotaka Sakurama, MD, Jun-ichi Kuratsu, MD, PhD Department of Neurosurgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-856, Japan Received 14 February 2005; accepted 31 March 2005
Abstract
Background: A spontaneous arteriovenous fistula of the orbit is exceedingly rare. We report the first case of such condition treated with direct surgical exposure of the superior ophthalmic vein (SOV) followed by embolization. Case Description: A 55-year-old man presented with upper lid swelling, conjunctival chemosis, and proptosis of the right eye. Angiography revealed an intraorbital shunt supplied by the ophthalmic artery whose venous drainage curved anteriorly to the SOV. Because transarterial and transvenous endovascular approaches to treat the fistula were impossible, we performed direct surgical exposure of the SOV followed by the embolization of the fistula. Postoperative angiograms demonstrated complete closure of the fistula. All symptoms had disappeared by 2 months after surgery. Conclusions: For appropriate treatment planning, it is necessary to identify the location of the shunt. In cases where transarterial and transvenous endovascular approaches to treat the fistula are difficult or impossible, direct surgical exposure of the SOV followed by embolization may accomplish complete closure of the fistula without significant risk for iatrogenic injury. D 2006 Elsevier Inc. All rights reserved.
Keywords:
Arteriovenous fistula; Ophthalmic artery; Orbit; Superior ophthalmic vein
1. Introduction
2. Case report
Arteriovenous fistulas (AVFs) in the orbit are quite rare, and most are part of facial arteriovenous malformations [1-5,7]. Arteriovenous fistulas develop from a single communication between an artery and a vein. Because the bypass of capillary beds results in decreased vascular resistance, regional blood flows preferentially through the fistula, thereby exposing the veins to increased intraluminal pressure. Successful treatment requires closure of the fistulas. We report clinical and radiological findings in a patient with a spontaneous AVF in the orbit. We discuss our experience with this patient and present an effective management strategy for similar cases.
2.1. History
T Corresponding author. Tel.: +81 96 373 5219; fax: +81 96 371 8064. E-mail address: [email protected] (J.-i. Hamada). 0090-3019/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2005.03.043
This 55-year-old man presented with a 6-month history of upper lid swelling, conjunctival chemosis, and proptosis of the right eye. There was no history of orbital trauma or family history of vascular disorders. 2.2. Examination and operation On admission, ophthalmologic examination disclosed marked dilatation of conjunctival vessels, chemosis, and exophthalmos of the right eye. Ocular movements were almost normal. Intraocular pressure was 22 mm Hg in the right eye and 10 mm Hg in the left eye. Neurologic examination showed no other deficits. Magnetic resonance imaging disclosed right exophthalmos, extraocular muscle enlargement, and a dilated superior ophthalmic vein (SOV) (Fig. 1). Early-phase angiograms revealed an enlarged abnormal branch of the ophthalmic artery that supplied the SOV after an abrupt change in its vascular caliber and
56
J.-i. Hamada et al. / Surgical Neurology 65 (2006) 55–57
because of fracture of the ethomoid bone with subsequent rupture of the artery into the ophthalmic venous system [4,6], the orbital AVF in our patient occurred spontaneously without trauma. The hemodynamic characteristics of AVFs in the orbit are comparable to those of orbital arteriovenous malformations or carotid-cavernous sinus fistulas. Increased
Fig. 1. T2-weighted magnetic resonance images showing right exophthalmos, extraocular muscle enlargement, and a dilated SOV (arrow).
course. The SOV drained anteriorly into several small tributaries with slow outflow (Fig. 2). No nidus and no draining into the cavernous sinus were observed. These findings were compatible with the diagnosis of AVF in the orbit. The feeding artery from the ophthalmic artery could not be subjected to arterial embolization. Because tributaries from the SOV also failed to provide access to treat the fistula (because their small size prevented cannulation necessary for embolization), we used the transcranial extradural approach. Opening the roof of the orbit and laterally retracting the superior rectus muscle revealed a dilated SOV. After interruption of this vein, intraoperative angiograms did not show complete disappearance of the fistula. Therefore, rectangular pieces of oxidized cellulose (Surgicel), about 2 2 3 mm, were inserted through the SOV. This packing of the SOV resulted in complete obliteration of the fistula on the intraoperative angiograms. 2.3. Postoperative course Although he experienced transient mild abducens palsy that resolved completely by the third week after surgery, his symptoms had disappeared by the second postoperative month. Angiograms obtained 6 months after surgery demonstrated the occlusion of the fistula, and he experienced no symptom recurrence (Fig. 3). 3. Discussion Arteriovenous malformations are congenital lesions with numerous, large feeding arteries, a central nidus, and many dilated draining veins. Arteriovenous fistulas, on the other hand, are characterized by a single arteriovenous connection within the vascular mass [2]. Although most AVFs in the orbit occur after injury to an ethomoid artery
Fig. 2. A: Superselective angiograms of the right ophthalmic artery demonstrating that a branch from the ophthalmic artery supplies the AVF. B: Venous drainage curved anteriorly to the SOV. The arrow indicates the location of the fistula. C: The SOV drained into several small tributaries with slow outflow.
J.-i. Hamada et al. / Surgical Neurology 65 (2006) 55–57
57
References [1] Chakrabortty S, Nagashima T, Izawa I, et al. Intraorbital arteriovenous malformation: case report. Surg Neurol 1993;40:320 - 5. [2] Hayes BH, Shore JW, Westfall CT, et al. Management of orbital and periorbital arteriovenous malformation. Ophthalmic Surg 1995;26: 145 - 52. [3] Kim JW, Stewart WB, Spencer WH, et al. Acute expansion of an orbital vascular malformation. Arch Ophthalmol 1999;117:844 - 5. [4] Kupersmith MJ. Neurovascular neuro-ophthalmology. Berlin7 SpringerVerlag; 1993. p. 69 - 108. [5] Ohtsuka K, Hashimoto M. Clinical findings in a patient with spontaneous arteriovenous fistulas of the orbit. Am J Ophthalmol 1999;127:736 - 7. [6] Trout HH, McAlister HA, Giordano JM, et al. Vascular malformations. Surgery 1985;97:36 - 41. [7] Wright JE. Orbital vascular anomalies. Trans Am Acad Ophthalmol Otolaryngol 1974;78:606 - 16. Fig. 3. Angiograms obtained 6 months after surgery show complete closure of the fistula.
Commentary venous pressure in the orbit and signs of orbital congestion, such as proptosis, dilation of conjunctival and retinal vessels, ocular hypertension, and dilation of the superior and inferior ophthalmic veins, can be found. Orbital symptoms are frequently related not only to the degree of shunt but also to the adequacy of external drainage of the SOV. Very slow flow shunts can result in severe proptosis and chemosis because of poor or nonexistent external drainage. Angiographically, AVFs are characterized by a single arteriovenous connection within the vascular mass. Abrupt changes in the vascular caliber and/or the course of the feeding pedicle mark the location of the shunt between the artery and vein. Proximal ligation of feeding arteries is inadequate because of the potential for retrograde flow and recruitment of collateral vessels. Therefore, successful treatment requires closure of the fistulas. We performed direct surgical exposure of the SOV and embolization with rectangular pieces of oxidized cellulose because transarterial and transvenous endovascular approaches to treat the fistula were impossible. If transvenous occlusion is to be performed, the site of embolization should be as close as possible to the fistula to prevent recruitment of collateral veins for drainage. Arteriovenous fistulas of the orbit must be considered in the differential diagnosis of carotid-cavernous sinus fistulas and arteriovenous malformations. In our case, where transarterial and transvenous endovascular approaches to treat the fistula were limited, direct surgical exposure of the SOV followed by embolization accomplished complete closure of the fistula without significant risk for iatrogenic injury.
Orbital vascular malformations are relatively rare. A well-known example is Wyburn-Mason syndrome, which consists of retinal and cerebral AVM, particularly along the optic pathways [1,2]. On the other hand, AVFs are usually traumatic in origin, and spontaneous forms, as reported here, seem extremely rare. The choice of treatment of AVF is obliteration of the fistulous point, approached from either arterial or venous side. The case reported here seems exceptional because dilated SOV diverged into several small tributaries, which makes the transvenous approach from the skin extremely difficult. Superior ophthalmic vein did not drain into cavernous sinus either. The authors thus used direct surgical exposure of SOV and packed (embolized) the fistulous point, rather than direct coagulation. This would indeed be less invasive if the fistulous point is located deep in the orbit. This case report demonstrated an alternative method in difficult cases for embolization. Nobutaka Kawahara, MD, PhD Department of Neurosurgery Graduate School of Medicine University of Tokyo Tokyo 113-8655, Japan References [1] Chan WM, Yip NK, Lam DS. Wyburn-Mason syndrome. Neurology 2004;62:99. [2] Ponce FA, Han PP, Spetzler RF, Canady A, Feiz-Erfan I. Associated arteriovenous malformation of the orbit and brain: a case of WyburnMason syndrome without retinal involvement. Case report. J Neurosurg 2001;95:346 - 9.