OPHTHALMIC FINDINGS IN DURAL ARTERIOVENOUS SHUNTS M. MADISON SLUSHER, MD and
B. RICHARD LENNINGTON, MD BY INVITATION
WINSTON-SALEM, NORTH CAROLINA RICHARD G. WEAVER, MD and
COURTLAND H. DAVIS, JR, MD BY INVITATION
WINSTON-SALEM, NORTH CAROLINA Five cases of dural carotid arteriovenous shunts in the region of the cavernous sinus are reported. Discussion of the specific carotid angiographic features stresses the pathophysiologic characteristics of these shunts in relation to the ophthalmic findings. In all cases, the meningohypophyseal artery was involv~d as the sole or predominant source of the afferent arterial supply, and the degree of proptosis, epibulbar congestion and secondary glaucoma correlated with retrograde filling of the superior ophthalmic vein from the cavernous sinus. The ophthalmologist's early recognition of this entity as a "spontaneous" pathologic occurrence is important, since he is intimately involved in its diagnosis and long-term management.
DuRAL arteriovenous shunts in the region of the cavernous sinus constitute a clinical entity that has received scant attention from ophthalmic literature. Newton and Hoyt1 have asserted that most "spontaneous" carotid cavernous fistulae consist of dural shunts between meningeal branches of the internal or external carotid artery and dural veins in the vicinity of the cavernous sinus; they reported 11 such cases in the neuroradiologic literature. Recent, isolated case reports have emphasized this as a distinct neuro-ophthalmologic entity and selective cerebral angiography as its definitive diagnostic procedure. 2 •3
Submitted for publication Oct 24, 1978. From the Section on Ophthalmology (Drs Slusher and Weaver) and the Section on Neurosurgery (Dr Davis), Department of Surgery, and the Section of Neuroradiology, Department of Radiology (Dr Lennington), Bowman Gray School of Medicine of Wake Forest University, WinstonSalem, North Carolina. Presented at the 1978 Annual Meeting of the American Academy of Ophthalmology, Kansas City, Mo, Oct 22-26. Reprint requests to Section on Ophthalmology, Bowman Gray School of Medicine, Winston-Salem, NC 27103 (Dr Slusher).
The purpose of this paper is to examine dural arteriovenous shunts from the ophthalmologist's standpoint, defining the diagnosis and pathophysiology in terms of selected carotid arteriography and discussing the ophthalmic findings and prognostic significance. Twentyeight cases of presumed carotid-cavernous fistulae that had been evaluated by the Sections
720
VOLUME 86 MAY 1979
DURAL ARTERIOVENOUS SHUNTS
on Ophthalmology, Neurosurgery and Neuroradiology at the Bowman Gray Medical Center over a 15-year period were reviewed. Five cases of dural arteriovenous shunts were identified from that group. Two cases had not initially been diagnos-ed as arteriovenous shunts on clinical examination; the correct diagnosis was made only by selective cerebral arteriography. CASE REPORTS
CASE 1.-An 80-year-old woman with a two- to three-week history of right retrobulbar pain, and a protruding and intensely red right eye, was referred to the center. Her best corrected visual acuity was 20/50 -2 in the right eye and 20/50 in the left eye. She showed 8 mm of right proptosis and noticeable engorgement and injection of her right epibulbar vessels (Fig 1). Intraocular pressure by applanation was 29 mm Hg in her right eye and 22 mm Hg in her left eye. There were no extraocular muscle palsies.
Fig 1.-Patient 1, 80-year-old woman. There is proptosis (8 mm) on right, as well as epibulbar vascular congestion.
The optic discs were normal and the retinal vasculature was bilaterally symmetric. There were diffuse macular pigmentary degenerative changes in both eyes and moderately advanced bilateral cataracts. No bruit could be heard over the eyes or in the head. The innominate angiographic injection indicated either dural arteriovenous malformation or a shunt on the dorsum sellae, filling from the right meningohypophyseal artery. The right superior ophthalmic vein filled retrogradely from the right cavernous sinus. Clinical Course: Two days after arteriography, the patient demonstrated definite
721
improvement in the epibulbar vascular injection, although the amount of proptosis remained the same. Intraocular pressure dropped to 24 mm Hg in the affected right eye. Three months later, however, the patient's original signs and symptoms had returned and a repeat carotid arteriogram was performed. Her dural arteriovenous shunt was again obvious as was filling from the left internal carotid artery (Fig 2). She was conservatively treated and she improved rapidly. Examination four years later indicated that the patient's vision was getting worse due to bilateral cataracts. She had normal discs and extraocular movements. The patient had only 3 mm of right proptosis (Fig 3). Her episcleral vessels appeared normal and the lOP by applanation was 22 mm Hg in each eye. CASE 2.-A 71-year-old woman was transferred to the Neurosurgical Service as a postoperative patient from another hospital. She had been diagnosed as having a carotid cavernous fistula and had undergone a left carotid clip occlusion and muscle embolization of the left internal and external carotid arteries several weeks before. Her history was one of sudden onset of proptosis and redness in the left eye six months before surgical treatment. At admission, she still had proptosis (7 mm) in, and epibulbar congestion of, the left eye. Ophthalmic examination revealed bilateral aphakia, diminution of vision in the left eye compared with the right (Jaeger 7 vs Jaeger 5), and the absence of a bruit over the left eye. Ocular rotations were not limited, and the optic discs were alike in appearance and color. Left common carotid artery injection revealed an enlarged ascending pharyngeal branch of the external carotid artery filling an arteriovenous structure along the course of the left inferior petrosal sinus and draining into the cavernous sinus. There was subsequent forward flow into the left superior ophthalmic vein. An enlarged left artery to the inferior cavernous sinus also contributed to the dural arteriovenous shunt. Clinical Course: The patient was conservatively treated during her hospital stay and was lost to follow-up after discharge. CAsE 3.-A 68-year-old woman first came to the attention of a neurologist after she experienced a seven-week period of right frontotemporal headache during her postoperative recovery from a hysterectomy. Diplopia and "swimmy-headedness" devel-
722
SLUSHER ET AL
OPHTH AAO
Fig 2.-Left internal carotid artery injection showing dural shunt (broadhead) filled from meningohypophyseal trunk and draining into right cavernous sinus (open arrow) with retrograde filling of left superior ophthalmic vein.
Fig 3.-Four-year follow-up photograph of patient in Fig 1. Only 3 mm of proptosis remains, and epibulbar vessels are no longer prominent.
oped shortly before her evaluation at the Bowman Gray Medical Center. Visual acuity was 20/25 in both eyes. Visual fields indicated no defect, but a total right third nerve palsy was present along with a dilated, unresponsive right pupil. No impression of proptosis was recorded. The optic discs were flat and of normal color. Selective injection of the right common carotid artery indicated an arteriovenous malformation on the dura of the clivus. Its primary arterial supply appeared to be an enlarged right meningohypophyseal trunk. A reticulated cluster of vessels over the greater wing of the right sphenoid was opacified. Flow was into the inferior petrosal sinus, and drainage into the cavernous sinus was not identified.
Clinical Course: Three months later the patient returned, complaining of a noise in her head and decreased vision in her right eye_ A bruit could be heard over the right eye. The optic discs had not changed, and no congestion of epibulbar or retinal vessels was noted. Repeat selective cerebral arteriography showed the dural arteriovenous shunt to be more apparent, with filling of the right cavernous sinus-a finding not present on the initial study. Because the patient's signs and symptoms were worsening, an intracranial ligation of the right carotid artery with muscle embolization of the shunt was performed. Postoperatively, the bruit the patient had heard disappeared. At a follow-up examination three years later, she had recovered most of her levator function, although she still had 3 mm of proptosis of the right eye. Her pupil remained fixed and nonreactive, but her extraocular movements showed some recovery, with so-called misdirection regenerative findings_ CAsE 4.-The referring ophthalmologist of a 64-year-old woman had seen her six months before her initial evaluation at the center; diplopia had been her only ocular complaint. That cleared spontaneously, but when she was seen at the center, a red,
VOLUME 86 MAY 1979
DURAL ARTERIOVENOUS SHUNTS
723
"swollen" right eye and moderate periocular pain had developed. She had undergone a coronary artery bypass procedure 18 months earlier for symptomatic coronary artery occlusive disease. Vision in the right eye was 20/30 -2; in her left eye, 20/25 -2. The pupils reacted normally. Visual fields were full. Extraocular movements were normal. She had proptosis (5 mm) of the right eye, and her lOPs by applanation were 30 mm Hg (right eye) and 20 mm Hg (left eye). There was probable venous engorgement of the retinal veins, but the optic discs were normal. Selective carotid arteriograms showed a dural arteriovenous malformation on the superior aspect of the clivus, which drained into the right cavernous sinus and filled the superior ophthalmic vein in a retrograde manner. Afferent arterial supply was from meningeal branches of both external carotid arteries and the meningohypophyseal trunk of the left internal carotid artery. The bulk of flow to the arteriovenous malformation appeared to be from the left external carotid and meningohypophyseal arteries; a small quantity came from the right meningeal artery (Fig 4).
Fig 4.-Left external carotid injection demon· strating filling of clival dural shunt (broadhead), drainage into cavernous sinus, and retrograde filling of right superior ophthalmic vein (arrows).
Clinical Course: The patient was conservatively treated, but continued to have an injected right eye, reduced vision, and 5 mm of proptosis (Fig 5). Two months after her initial visit, a sudden onset of
Fig 5.-Patient 4, 64-year-old woman, who presented initially with 5 mm of proptosis and prominent epibulbar vessels.
severe pain and swelling about the right globe occurred. Her vision had decreased to 20/50 in the right eye and lOP in that eye had risen to 60 mm Hg. A flame-shaped hemorrhage was now noted in her right fundus. The conjunctiva on the right was slightly chemotic, and her right globe was approximately 9 mm proptotic. Repeat selective cerebral arteriograms suggested prompt and equal filling from the meningeal branches of both external carotid arteries into the diva! plexus of vessels, the right cavernous sinus, and the right superior ophthalmic vein. The patient improved rapidly following this second arteriographic study and, within • three days, proptosis of her right eye was 3 to 4 mm, lOP had dropped to 26 mm Hg, and visual acuity had improved to 20/30. She remained asymptomatic for two years, and at latest follow-up, visual acuity in the right eye was 20/20 and lOP in that eye was 17 mm Hg. The fundus vasculature was symmetric. Only 1 to 2 mm of proptosis could be measured, and there was no sign of dilated epibulbar vessels (Fig 6).
Fig 6.-Two·year follow-up of patient in Fig 5. Proptosis is only 1 to 2 mm, lOP is normal, and epibulbar vascular congestion has resolved.
CAsE 5.-A 66-year-old woman with hypertension and a two-month history of progressive, painless, right proptosis was referred to the center. Systemic evaluation before her referral included optic foramina films and endocrine studies, which showed no abnormal findings. On her initial ophthal-
724
SLUSHER ET AL
mic evaluation at the center, visual acuity was 20/40 for both eyes, but was subjectively better for the left. Extraocular movements were full, and the pupils reacted normally. The right episcleral vessels were markedly injected (Fig 7), and there was conjunctival chemosis. Hertel readings indicated a right proptosis of 5 mm; the proptosis was pulsatile, but no bruit could be heard. Intraocular pressure by applanation was 39 mm Hg (right eye) and 23 mm Hg (left eye). The optic discs were asymmetric. The right optic disc showed hyperemia and minute splinter hemorrhages. Selective carotid arteriography indicated a dural arteriovenous shunt on the dorsum sellae that was supplied by the meningohypophyseal trunk of the right internal carotid artery. Drainage was into the cavernous sinus, producing forward filling of the superior ophthalmic veins (Fig 8).
Fig 7.-Dilated tortuous episcleral vessel in patient
fi. Intraocular pressure is 39 mm Hg, and globe
is 5 mm proptotic.
Clinical Course: During the patient's hospitalization, adult-onset diabetes was diagnosed, and she was placed on insulin therapy. Following arteriography, some remission of her signs occurred, but the lOP for her right eye remained elevated at 27 mm Hg. Four months after the patient's initial evaluation, her visual acuity had improved to 20/30, and the optic disc had become less hyperemic. The proptosis had not changed.
DISCUSSION
The exact cause of dural arteriovenous shunts remains unknown. Various authors 1 •2 have speculated
OPHTH AAO
Fig 8.-Left internal carotid injectio11 demon· strating dural shunt on clivus (broadhead), filled from meningohypophyseal trunk with drainage into cavernous sinus (open arrows) and retrograde filling of right superior ophthalmic vein.
that they represent congenital malformations or that they develop due to the rupture of very thin-walled vessels in the cavernous sinus itself on the basis of underlying vascular disease or trauma. Two of the five patients had well-documented vascular disease: Patient 4 had cerebral arteriosclerotic changes, documented by arteriograms, and had undergone a coronary artery bypass procedure for symptomatic coronary artery occlusive disease 12 months before onset of the symptoms caused by her dural arteriovenous shunt. Patient 5 was diabetic and hypertensive. None of the patients had a history of trauma. All were over 60 years of age, and all were women, fitting into an apparent sexual predisposition documented by Taniguchi et al. 4 Angiographically, the shunts were usually identified as a tangle of small vessels with shunting of opacified blood into a venous struc-
GASSERIAN GANGUOM
Fig 9.-Top, View from above of normal anatomic relationships of cranial vascular anatomy in region of cavernous sinus. Bottom, Lateral diagram of cavernous sinus area showing relationship of cranial nerves in area to arterial vasculature.
R6 1879
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DURAL ARTERIOVENOUS SHUNTS
ture. Although other authors 4 have stressed their difficulties with angiographic diagnosis, in this study, selective cerebral arteriography made a definitive diagnosis possible. The majority of the malformations that occur are supplied by arteries arising near the shunt. Two branches of the cavernous carotid artery are commonly involved: the meningohypophyseal trunk and the artery to the inferior cavernous sinus. The meningohypophyseal trunk originates from the proximal dorsal cavernous carotid artery and supplies blood to the clival dura, inferior cavernous sinus structures, tentorium, and posterior hypophysis (Fig 9). Barely identifiable on a normal angiogram (Fig 10), the meningohypophyseal trunk may enlarge as it supplies flow to a shunt. In all five of the patients in this study and in six of the 11 patients studied by Newton and Hoyt, 1 the shunt received blood from the meningohypophyseal trunk.
Fig 10.-Common carotid arteriogram showing normal meningohypophyseal trunk (arrow). Its small size makes it barely visible angiographically.
727
The inferior cavernous sinus artery originates from the lateral side of the mid-cavernous carotid artery (Fig 9). It normally supplies structures of the inferior cavernous sinus; it provided shunt flow in one of the five patients in this study and in four of Newton and Hoyt's patients. The external carotid artery contributes frequently to shunt flow through small arterial channels originating near the meningeal artery foramina and passing within the dura to the parasellar region. Parkinson5 demonstrated in vitro the connection of those collateral channels with cavernous sinus arterial branches. In four of the patients in this study, the shunt received circulation in that manner; in the fifth patient, the shunt derived circulation from meningeal branches of an ascending pharyngeal artery. Four of the five shunts received blood from both the internal and the external carotid artery. Venous drainage from four shunts was into the cavernous sinus, with subsequent retrograde filling of the superior ophthalmic vein. The ocular signs and symptoms and the frequency of their occurrence in the five patients are shown in Table 1. The signs and symptoms are identical to those cited by several other authors 1- 4 and include headache, proptosis, dilated episcleral vessels, elevated lOP, objective and subjective bruits, cranial nerve palsy, and blurred vision. Unlike the patients reported by Newton and Hoyt, 1 no patients had severe visual loss or blindness. Unilateral sixth nerve palsy was not observed in any of the patients, as it had been in seven of Newton and Hoyt's patients, but patient 3 had a profound palsy of the third
728
SLUSHER ET AL
OPHTH AAO
cranial nerve on her right side. -Over a four-year period, that palsy has shown some regenerative efforts of a misdirected type (Fig 11). None of the patients with transient visual disturbance had choroidal changes like those in the patient reported by Harbison et aP.
r.l
> E= ~
(/J
2 ~ E-
B. RICHARD LENNINGTON, MD BY INVITATION
WINSTON-SALEM, NORTH CAROLINA RICHARD G. WEAVER, MD and
COURTLAND H. DAVIS, JR, MD BY INVITATION
WINSTON-SALEM, NORTH CAROLINA Five cases of dural carotid arteriovenous shunts in the region of the cavernous sinus are reported. Discussion of the specific carotid angiographic features stresses the pathophysiologic characteristics of these shunts in relation to the ophthalmic findings. In all cases, the meningohypophyseal artery was involv~d as the sole or predominant source of the afferent arterial supply, and the degree of proptosis, epibulbar congestion and secondary glaucoma correlated with retrograde filling of the superior ophthalmic vein from the cavernous sinus. The ophthalmologist's early recognition of this entity as a "spontaneous" pathologic occurrence is important, since he is intimately involved in its diagnosis and long-term management.
DuRAL arteriovenous shunts in the region of the cavernous sinus constitute a clinical entity that has received scant attention from ophthalmic literature. Newton and Hoyt1 have asserted that most "spontaneous" carotid cavernous fistulae consist of dural shunts between meningeal branches of the internal or external carotid artery and dural veins in the vicinity of the cavernous sinus; they reported 11 such cases in the neuroradiologic literature. Recent, isolated case reports have emphasized this as a distinct neuro-ophthalmologic entity and selective cerebral angiography as its definitive diagnostic procedure. 2 •3
Submitted for publication Oct 24, 1978. From the Section on Ophthalmology (Drs Slusher and Weaver) and the Section on Neurosurgery (Dr Davis), Department of Surgery, and the Section of Neuroradiology, Department of Radiology (Dr Lennington), Bowman Gray School of Medicine of Wake Forest University, WinstonSalem, North Carolina. Presented at the 1978 Annual Meeting of the American Academy of Ophthalmology, Kansas City, Mo, Oct 22-26. Reprint requests to Section on Ophthalmology, Bowman Gray School of Medicine, Winston-Salem, NC 27103 (Dr Slusher).
The purpose of this paper is to examine dural arteriovenous shunts from the ophthalmologist's standpoint, defining the diagnosis and pathophysiology in terms of selected carotid arteriography and discussing the ophthalmic findings and prognostic significance. Twentyeight cases of presumed carotid-cavernous fistulae that had been evaluated by the Sections
720
VOLUME 86 MAY 1979
DURAL ARTERIOVENOUS SHUNTS
on Ophthalmology, Neurosurgery and Neuroradiology at the Bowman Gray Medical Center over a 15-year period were reviewed. Five cases of dural arteriovenous shunts were identified from that group. Two cases had not initially been diagnos-ed as arteriovenous shunts on clinical examination; the correct diagnosis was made only by selective cerebral arteriography. CASE REPORTS
CASE 1.-An 80-year-old woman with a two- to three-week history of right retrobulbar pain, and a protruding and intensely red right eye, was referred to the center. Her best corrected visual acuity was 20/50 -2 in the right eye and 20/50 in the left eye. She showed 8 mm of right proptosis and noticeable engorgement and injection of her right epibulbar vessels (Fig 1). Intraocular pressure by applanation was 29 mm Hg in her right eye and 22 mm Hg in her left eye. There were no extraocular muscle palsies.
Fig 1.-Patient 1, 80-year-old woman. There is proptosis (8 mm) on right, as well as epibulbar vascular congestion.
The optic discs were normal and the retinal vasculature was bilaterally symmetric. There were diffuse macular pigmentary degenerative changes in both eyes and moderately advanced bilateral cataracts. No bruit could be heard over the eyes or in the head. The innominate angiographic injection indicated either dural arteriovenous malformation or a shunt on the dorsum sellae, filling from the right meningohypophyseal artery. The right superior ophthalmic vein filled retrogradely from the right cavernous sinus. Clinical Course: Two days after arteriography, the patient demonstrated definite
721
improvement in the epibulbar vascular injection, although the amount of proptosis remained the same. Intraocular pressure dropped to 24 mm Hg in the affected right eye. Three months later, however, the patient's original signs and symptoms had returned and a repeat carotid arteriogram was performed. Her dural arteriovenous shunt was again obvious as was filling from the left internal carotid artery (Fig 2). She was conservatively treated and she improved rapidly. Examination four years later indicated that the patient's vision was getting worse due to bilateral cataracts. She had normal discs and extraocular movements. The patient had only 3 mm of right proptosis (Fig 3). Her episcleral vessels appeared normal and the lOP by applanation was 22 mm Hg in each eye. CASE 2.-A 71-year-old woman was transferred to the Neurosurgical Service as a postoperative patient from another hospital. She had been diagnosed as having a carotid cavernous fistula and had undergone a left carotid clip occlusion and muscle embolization of the left internal and external carotid arteries several weeks before. Her history was one of sudden onset of proptosis and redness in the left eye six months before surgical treatment. At admission, she still had proptosis (7 mm) in, and epibulbar congestion of, the left eye. Ophthalmic examination revealed bilateral aphakia, diminution of vision in the left eye compared with the right (Jaeger 7 vs Jaeger 5), and the absence of a bruit over the left eye. Ocular rotations were not limited, and the optic discs were alike in appearance and color. Left common carotid artery injection revealed an enlarged ascending pharyngeal branch of the external carotid artery filling an arteriovenous structure along the course of the left inferior petrosal sinus and draining into the cavernous sinus. There was subsequent forward flow into the left superior ophthalmic vein. An enlarged left artery to the inferior cavernous sinus also contributed to the dural arteriovenous shunt. Clinical Course: The patient was conservatively treated during her hospital stay and was lost to follow-up after discharge. CAsE 3.-A 68-year-old woman first came to the attention of a neurologist after she experienced a seven-week period of right frontotemporal headache during her postoperative recovery from a hysterectomy. Diplopia and "swimmy-headedness" devel-
722
SLUSHER ET AL
OPHTH AAO
Fig 2.-Left internal carotid artery injection showing dural shunt (broadhead) filled from meningohypophyseal trunk and draining into right cavernous sinus (open arrow) with retrograde filling of left superior ophthalmic vein.
Fig 3.-Four-year follow-up photograph of patient in Fig 1. Only 3 mm of proptosis remains, and epibulbar vessels are no longer prominent.
oped shortly before her evaluation at the Bowman Gray Medical Center. Visual acuity was 20/25 in both eyes. Visual fields indicated no defect, but a total right third nerve palsy was present along with a dilated, unresponsive right pupil. No impression of proptosis was recorded. The optic discs were flat and of normal color. Selective injection of the right common carotid artery indicated an arteriovenous malformation on the dura of the clivus. Its primary arterial supply appeared to be an enlarged right meningohypophyseal trunk. A reticulated cluster of vessels over the greater wing of the right sphenoid was opacified. Flow was into the inferior petrosal sinus, and drainage into the cavernous sinus was not identified.
Clinical Course: Three months later the patient returned, complaining of a noise in her head and decreased vision in her right eye_ A bruit could be heard over the right eye. The optic discs had not changed, and no congestion of epibulbar or retinal vessels was noted. Repeat selective cerebral arteriography showed the dural arteriovenous shunt to be more apparent, with filling of the right cavernous sinus-a finding not present on the initial study. Because the patient's signs and symptoms were worsening, an intracranial ligation of the right carotid artery with muscle embolization of the shunt was performed. Postoperatively, the bruit the patient had heard disappeared. At a follow-up examination three years later, she had recovered most of her levator function, although she still had 3 mm of proptosis of the right eye. Her pupil remained fixed and nonreactive, but her extraocular movements showed some recovery, with so-called misdirection regenerative findings_ CAsE 4.-The referring ophthalmologist of a 64-year-old woman had seen her six months before her initial evaluation at the center; diplopia had been her only ocular complaint. That cleared spontaneously, but when she was seen at the center, a red,
VOLUME 86 MAY 1979
DURAL ARTERIOVENOUS SHUNTS
723
"swollen" right eye and moderate periocular pain had developed. She had undergone a coronary artery bypass procedure 18 months earlier for symptomatic coronary artery occlusive disease. Vision in the right eye was 20/30 -2; in her left eye, 20/25 -2. The pupils reacted normally. Visual fields were full. Extraocular movements were normal. She had proptosis (5 mm) of the right eye, and her lOPs by applanation were 30 mm Hg (right eye) and 20 mm Hg (left eye). There was probable venous engorgement of the retinal veins, but the optic discs were normal. Selective carotid arteriograms showed a dural arteriovenous malformation on the superior aspect of the clivus, which drained into the right cavernous sinus and filled the superior ophthalmic vein in a retrograde manner. Afferent arterial supply was from meningeal branches of both external carotid arteries and the meningohypophyseal trunk of the left internal carotid artery. The bulk of flow to the arteriovenous malformation appeared to be from the left external carotid and meningohypophyseal arteries; a small quantity came from the right meningeal artery (Fig 4).
Fig 4.-Left external carotid injection demon· strating filling of clival dural shunt (broadhead), drainage into cavernous sinus, and retrograde filling of right superior ophthalmic vein (arrows).
Clinical Course: The patient was conservatively treated, but continued to have an injected right eye, reduced vision, and 5 mm of proptosis (Fig 5). Two months after her initial visit, a sudden onset of
Fig 5.-Patient 4, 64-year-old woman, who presented initially with 5 mm of proptosis and prominent epibulbar vessels.
severe pain and swelling about the right globe occurred. Her vision had decreased to 20/50 in the right eye and lOP in that eye had risen to 60 mm Hg. A flame-shaped hemorrhage was now noted in her right fundus. The conjunctiva on the right was slightly chemotic, and her right globe was approximately 9 mm proptotic. Repeat selective cerebral arteriograms suggested prompt and equal filling from the meningeal branches of both external carotid arteries into the diva! plexus of vessels, the right cavernous sinus, and the right superior ophthalmic vein. The patient improved rapidly following this second arteriographic study and, within • three days, proptosis of her right eye was 3 to 4 mm, lOP had dropped to 26 mm Hg, and visual acuity had improved to 20/30. She remained asymptomatic for two years, and at latest follow-up, visual acuity in the right eye was 20/20 and lOP in that eye was 17 mm Hg. The fundus vasculature was symmetric. Only 1 to 2 mm of proptosis could be measured, and there was no sign of dilated epibulbar vessels (Fig 6).
Fig 6.-Two·year follow-up of patient in Fig 5. Proptosis is only 1 to 2 mm, lOP is normal, and epibulbar vascular congestion has resolved.
CAsE 5.-A 66-year-old woman with hypertension and a two-month history of progressive, painless, right proptosis was referred to the center. Systemic evaluation before her referral included optic foramina films and endocrine studies, which showed no abnormal findings. On her initial ophthal-
724
SLUSHER ET AL
mic evaluation at the center, visual acuity was 20/40 for both eyes, but was subjectively better for the left. Extraocular movements were full, and the pupils reacted normally. The right episcleral vessels were markedly injected (Fig 7), and there was conjunctival chemosis. Hertel readings indicated a right proptosis of 5 mm; the proptosis was pulsatile, but no bruit could be heard. Intraocular pressure by applanation was 39 mm Hg (right eye) and 23 mm Hg (left eye). The optic discs were asymmetric. The right optic disc showed hyperemia and minute splinter hemorrhages. Selective carotid arteriography indicated a dural arteriovenous shunt on the dorsum sellae that was supplied by the meningohypophyseal trunk of the right internal carotid artery. Drainage was into the cavernous sinus, producing forward filling of the superior ophthalmic veins (Fig 8).
Fig 7.-Dilated tortuous episcleral vessel in patient
fi. Intraocular pressure is 39 mm Hg, and globe
is 5 mm proptotic.
Clinical Course: During the patient's hospitalization, adult-onset diabetes was diagnosed, and she was placed on insulin therapy. Following arteriography, some remission of her signs occurred, but the lOP for her right eye remained elevated at 27 mm Hg. Four months after the patient's initial evaluation, her visual acuity had improved to 20/30, and the optic disc had become less hyperemic. The proptosis had not changed.
DISCUSSION
The exact cause of dural arteriovenous shunts remains unknown. Various authors 1 •2 have speculated
OPHTH AAO
Fig 8.-Left internal carotid injectio11 demon· strating dural shunt on clivus (broadhead), filled from meningohypophyseal trunk with drainage into cavernous sinus (open arrows) and retrograde filling of right superior ophthalmic vein.
that they represent congenital malformations or that they develop due to the rupture of very thin-walled vessels in the cavernous sinus itself on the basis of underlying vascular disease or trauma. Two of the five patients had well-documented vascular disease: Patient 4 had cerebral arteriosclerotic changes, documented by arteriograms, and had undergone a coronary artery bypass procedure for symptomatic coronary artery occlusive disease 12 months before onset of the symptoms caused by her dural arteriovenous shunt. Patient 5 was diabetic and hypertensive. None of the patients had a history of trauma. All were over 60 years of age, and all were women, fitting into an apparent sexual predisposition documented by Taniguchi et al. 4 Angiographically, the shunts were usually identified as a tangle of small vessels with shunting of opacified blood into a venous struc-
GASSERIAN GANGUOM
Fig 9.-Top, View from above of normal anatomic relationships of cranial vascular anatomy in region of cavernous sinus. Bottom, Lateral diagram of cavernous sinus area showing relationship of cranial nerves in area to arterial vasculature.
R6 1879
VOLUME
MAY
DURAL ARTERIOVENOUS SHUNTS
ture. Although other authors 4 have stressed their difficulties with angiographic diagnosis, in this study, selective cerebral arteriography made a definitive diagnosis possible. The majority of the malformations that occur are supplied by arteries arising near the shunt. Two branches of the cavernous carotid artery are commonly involved: the meningohypophyseal trunk and the artery to the inferior cavernous sinus. The meningohypophyseal trunk originates from the proximal dorsal cavernous carotid artery and supplies blood to the clival dura, inferior cavernous sinus structures, tentorium, and posterior hypophysis (Fig 9). Barely identifiable on a normal angiogram (Fig 10), the meningohypophyseal trunk may enlarge as it supplies flow to a shunt. In all five of the patients in this study and in six of the 11 patients studied by Newton and Hoyt, 1 the shunt received blood from the meningohypophyseal trunk.
Fig 10.-Common carotid arteriogram showing normal meningohypophyseal trunk (arrow). Its small size makes it barely visible angiographically.
727
The inferior cavernous sinus artery originates from the lateral side of the mid-cavernous carotid artery (Fig 9). It normally supplies structures of the inferior cavernous sinus; it provided shunt flow in one of the five patients in this study and in four of Newton and Hoyt's patients. The external carotid artery contributes frequently to shunt flow through small arterial channels originating near the meningeal artery foramina and passing within the dura to the parasellar region. Parkinson5 demonstrated in vitro the connection of those collateral channels with cavernous sinus arterial branches. In four of the patients in this study, the shunt received circulation in that manner; in the fifth patient, the shunt derived circulation from meningeal branches of an ascending pharyngeal artery. Four of the five shunts received blood from both the internal and the external carotid artery. Venous drainage from four shunts was into the cavernous sinus, with subsequent retrograde filling of the superior ophthalmic vein. The ocular signs and symptoms and the frequency of their occurrence in the five patients are shown in Table 1. The signs and symptoms are identical to those cited by several other authors 1- 4 and include headache, proptosis, dilated episcleral vessels, elevated lOP, objective and subjective bruits, cranial nerve palsy, and blurred vision. Unlike the patients reported by Newton and Hoyt, 1 no patients had severe visual loss or blindness. Unilateral sixth nerve palsy was not observed in any of the patients, as it had been in seven of Newton and Hoyt's patients, but patient 3 had a profound palsy of the third
728
SLUSHER ET AL
OPHTH AAO
cranial nerve on her right side. -Over a four-year period, that palsy has shown some regenerative efforts of a misdirected type (Fig 11). None of the patients with transient visual disturbance had choroidal changes like those in the patient reported by Harbison et aP.
r.l
> E= ~
(/J
2 ~ E-
