CASE REPORT Cervical Spine Dural Arteriovenous Fistula With Coexisting Spinal Radiculopial Artery Aneurysm Presenting as Subarachnoid Hemorrhage: Case Report Joshua W. Lucas, BS Jesse Jones, MD Azadeh Farin, MD Paul Kim, MD Steven L. Giannotta, MD Department of Neurosurgery, Keck School of Medicine, University of Southern California, Los Angeles, California Correspondence: Joshua W. Lucas, BS, 1200 N State St, Suite 3300, Los Angeles, CA 90089. E-mail: joshualu@usc.edu Received, September 14, 2010. Accepted, February 22, 2011. Published Online, June 28, 2011. Copyright ª 2011 by the Congress of Neurological Surgeons BACKGROUND AND IMPORTANCE: We present a patient with a cervical spine dural arteriovenous fistula associated with a radiculopial artery aneurysm at the same vertebral level presenting with subarachnoid hemorrhage. CLINICAL PRESENTATION: A 45-year-old Native American man presented with suddenonset severe headache, lethargy, and right hemiparesis. Computed tomography (CT) of the head showed subarachnoid hemorrhage and hydrocephalus. A subsequent CT of the neck showed an anterior spinal subdural hematoma from C2 to C4 causing mild cord compression. Carotid and vertebral angiography failed to demonstrate an intracranial aneurysm, but showed a spinal dural arteriovenous fistula originating from the right vertebral artery at the C5 neuroforamen. The severity of the patient’s symptoms, atypical for rupture of a dural arteriovenous fistula, prompted more thorough angiographic evaluation. Thus, injection of the right thyrocervical trunk was performed, demonstrating a 4-mm spinal radiculopial artery aneurysm. Following ventriculostomy, a hemilaminectomy from C4 to C7 was performed with disconnection of the fistula from its drainage system. Subsequent resection of the aneurysm, which was determined to be the cause of the hemorrhage, was accomplished. The patient improved neurologically and was discharged to rehabilitation. CONCLUSION: Spinal cord aneurysms from a separate vascular distribution may coexist with spinal dural arteriovenous fistulas. In the setting of spinal hemorrhage, especially in situations with an atypical clinical presentation, comprehensive imaging is indicated to rule out such lesions. KEY WORDS: Aneurysm, Dural arteriovenous fistula, Subarachnoid hemorrhage Neurosurgery 70:E259–E263, 2012 DOI: 10.1227/NEU.0b013e31822ac0fb S pinal dural arteriovenous fistulas (dAVFs) are the most common type of spinal vascular malformations, comprising 60 to 80% of such lesions.1,2 Spinal dAVFs are acquired lesions representing an abnormal connection between a dural branch of a radicular artery and vein along the spinal dural surface, forming in response to poorly understood pathophysiologic mechanisms.2-4 Most dAVFs are found at the neural foramina of the thoracolumbar junction, but they may arise at any spinal level.2,3 ABBREVIATIONS: dAVF, dural arteriovenous fistulas; SAH, subarachnoid hemorrhage NEUROSURGERY www.neurosurgery-online.com Lesions in the thoracolumbar region manifest as progressive myelopathy with spastic paraparesis, sensory disturbances, or genitosphincteric dysfunction.1,3 Craniocervical spinal dAVFs can present with similar symptoms, but are distinguished by a propensity for causing subarachnoid hemorrhage (SAH) and cranial nerve dysfunction.3,5,6 Rupture of craniocervical dAVFs, although rare, typically produces lowgrade subarachnoid hemorrhage. Here, we present an unusual case of a dAVF originating from branches of the vertebral artery and a coexisting aneurysm of the spinal pial circulation in a patient presenting with moderate-grade SAH. VOLUME 70 | NUMBER 1 | JANUARY 2012 | E259 Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited. LUCAS ET AL CASE REPORT A 45-year-old Native American man presented with sudden-onset severe headache. The patient also reported light sensitivity, neck pain and stiffness, nausea, and one episode of emesis. He was confused and lethargic with a Glasgow Coma Score of 13, and 2/5 strength in his right upper extremity with 4/5 strength in his right lower extremity. The patient admitted to a 10-year history of daily intravenous drug abuse. Of note, he denied a history of fevers, chills, or other symptoms of acute infection. A noncontrast head computed tomography (CT) revealed extensive SAH in the upper cervical region and the basilar cisterns, and intraventricular hemorrhage with hydrocephalus (Figure 1). Subsequently, a CT angiogram of the head and neck to assess for a vascular etiology revealed an anterior spinal subdural hematoma extending from C2 to C4 causing mild cord compression (Figure 2). Also, a prominence of vessels surrounding the cord suggestive of a vascular malformation within the spinal canal was identified. A separate focus of hyperdensity at the C4/C5 level suggestive of an aneurysm was also noted (Figure 3). Magnetic resonance imaging of the cervical spine was strongly supportive of these findings (Figure 4). Comprehensive cerebral and spinal cord angiography was subsequently performed. Injection of the right vertebral artery demonstrated an abnormally enlarged radicular artery at the C5 level and a dAVF at the C5 neuroforamen with a cranially directed draining vein extending to the suboccipital region (Figure 5). Based on the presence of posterior fossa SAH with an anterior spinal subdural hematoma, and the focus of hyperdensity seen on CT, injection of the right thyrocervical trunk was performed. This demonstrated a radiculopial artery aneurysm measuring 4 mm in diameter located anteriorly within the spinal canal at the level of the C4/C5 disc (Figure 6A and 6B). No intracranial vascular abnormalities or other anomalies were identified. These findings were consistent with a category IV subtype III spinal dAVF at the C5 neuroforamen and a radiculopial artery aneurysm at the level of the subdural hematoma fed by distal branches of the thyrocervical trunk. FIGURE 1. Axial CT scan of the head showing subarachnoid hemorrhage and intraventricular hemorrhage. E260 | VOLUME 70 | NUMBER 1 | JANUARY 2012 FIGURE 2. Sagittal CT scan of the cervical spine with contrast demonstrating an anterior subdural mass extending from C2 to C4 and a focus of enhancement at the C4/C5 disc. On postbleed day 4, the patient underwent a C4 to C7 right-sided hemilaminectomy with ligation of the dAVF and resection of the radiculopial artery aneurysm. Intraoperative angiography showed occlusion and absence of both lesions (Figure 7). The patient subsequently improved to a Glasgow Coma Score of 15 with 4+/5 strength in his right FIGURE 3. Axial CT scan with contrast through C4/C5 showing the anterior focus of enhancement later determined to be a radiculopial aneurysm and the posterior draining vein of the dAVF. www.neurosurgery-online.com Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited. CERVICAL dAVF WITH RADICULOPIAL ANEURYSM FIGURE 4. Sagittal T2-weighted magnetic resonance imaging of the cervical spine demonstrating a hyperintense ovoid lesion at the levels of C2 to C4 and multiple flow voids in the same location. upper extremity and 5/5 strength in his right lower extremity, and was discharged to rehabilitation. Histologic evaluation of the aneurysm demonstrated an arterial wall without evidence of infection, excluding the possibility of a mycotic aneurysm or pseudoaneurysm. DISCUSSION Craniocervical dAVFs, although uncommon, have been wellcharacterized in the literature. SAH has been reported to occur in 34 to 45% of cases.2,5,6 When associated with hemorrhage, cases of dAVF rupture are usually characterized by a more benign clinical course than with aneurysm rupture. Fassett et al3 found that 95% of patients with craniocervical dAVF-related SAH presented with Hunt and Hess grade I or II hemorrhage, and no patients presented with Hunt and Hess grade IV or V hemorrhage. A large percentage of these patients had lesions with a cephalad or intracranially directed drainage pattern.5,6 Comparatively, 50 to 60% of patients with aneurysm-related SAH present with Hunt and Hess grade I or II hemorrhage, while 17 to 30% present with Hunt and Hess grade IV or V hemorrhage.7,8 This patient, however, presented with moderate- to severegrade SAH necessitating a ventriculostomy, clearly atypical for a craniocervical dAVF rupture. Upon discovery of the dAVF with injection of the right vertebral artery, this case could easily have been misdiagnosed as a dAVF alone. The discrepancy between NEUROSURGERY FIGURE 5. Injection of the right vertebral artery revealing a spinal dural arteriovenous fistula with a large feeding vessel originating from the level of C5 and a posterior cranially directed draining vein. the patient’s severity of SAH and that diagnosis, along with key findings on CT, heightened our suspicion that some other process might be responsible for the hemorrhage. Thus, injection of the right thyrocervical trunk was performed, demonstrating the coexisting radiculopial artery aneurysm. We were confident, based on the anterior location of both the spinal subdural hematoma and the aneurysm, that the aneurysm was the source of the hemorrhage. The radiculopial artery aneurysm in this patient arose anteriorly from pial branches fed by the thyrocervical trunk. The dAVF, while located at the same vertebral level, arose posteriorly from right vertebral artery branches. Intraoperatively, the aneurysm was determined to be the lesion that ruptured based on its appearance and proximity to the anterior spinal subdural hematoma. There is no definite explanation for the presence of the simultaneous lesions found in this patient. An association between dAVFs and aneurysms has only rarely been reported in the literature.9 However, other complex vascular structures such as arteriovenous malformations and multiple dAVFs have been found to coexist with dAVFs more frequently.10 As low-flow lesions, dAVFs rarely produce enough hemodynamic stress on the arterial walls to induce aneurysm formation of feeding arteries. Isolated aneurysms of the anterior spinal artery proper or VOLUME 70 | NUMBER 1 | JANUARY 2012 | E261 Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited. LUCAS ET AL FIGURE 6. Injection of the right thyrocervical trunk demonstrating a radiculopial artery aneurysm within the spinal canal measuring 4 mm in diameter at the level of C4/C5. A, anteroposterior view. B, lateral view. branches of the anterior spinal artery are also rare lesions, but when present are often associated with SAH.11,12 The decision to proceed with an open microsurgical technique was made to allow for complete treatment of both the aneurysm and dAVF. The subdural hematoma was large enough to compress the cervical spinal cord, so a longer laminectomy was performed to aid in decompression. Based on the patient’s long history of intravenous drug abuse, we were suspicious that the radiculopial artery aneurysm might have actually been a mycotic aneurysm. However, no active infection was identified, and final pathological analysis of the aneurysm wall confirmed that the aneurysm was not mycotic. The lesions in this patient highlight the possibility that craniocervical dAVFs and aneurysms of the spinal cord may coexist. Without additional clues from the CT scan and the patient’s uncharacteristic presentation, the SAH and spinal hemorrhage might have mistakenly been attributed to rupture of the dAVF, leaving the true cause of the hemorrhage undiscovered. Thus, it is reasonable to conclude that early progression to more comprehensive vascular imaging studies in the diagnostic algorithm may be indicated to assess for the presence of such simultaneous lesions. Disclosure The authors have no personal financial or institutional interest in any of the drugs, materials, or devices described in this article. REFERENCES FIGURE 7. Postoperative angiogram of the right vertebral artery displaying complete resolution of the spinal dural arteriovenous fistula. E262 | VOLUME 70 | NUMBER 1 | JANUARY 2012 1. Sivakumar W, Zada G, Yashar P, Giannotta SL, Teitelbaum G, Larsen DW. Endovascular management of spinal dural arteriovenous fistulas. A review. Neurosurg Focus. 2009;26(5):E15. 2. Guo LM, Zhou HY, Xu JW, et al. Dural arteriovenous fistula at the foramen magnum presenting with subarachnoid hemorrhage: case reports and literature review. Eur J Neurol. 2010;17(5):684-691. 3. Fassett DR, Rammos SK, Patel P, Parikh H, Couldwell WT. Intracranial subarachnoid hemorrhage resulting from cervical spine dural arteriovenous fistulas: literature review and case presentation. Neurosurg Focus. 2009;26(1):E4. www.neurosurgery-online.com Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited. CERVICAL dAVF WITH RADICULOPIAL ANEURYSM 4. Narvid J, Hetts SW, Larsen D, et al. Spinal dural arteriovenous fistulae: clinical features and long-term results. Neurosurgery. 2008;62(1):159-167. 5. Aviv RI, Shad A, Tomlinson G, et al. Cervical dural arteriovenous fistulae manifesting as subarachnoid hemorrhage: report of two cases and literature review. Am J Neuroradiol. 2004;25(5):854-858. 6. Kai Y, Hamada J, Morioka M, Yano S, Mizuno T, Kuratsu J. Arteriovenous fistulas at the cervicomedullary junction presenting with subarachnoid hemorrhage: six case reports with special reference to the angiographic pattern of venous drainage. Am J Neuroradiol. 2005;26(8):1949-1954. 7. Kassell NF, Torner JC, Jane JA, Haley JC Jr, Adams HP. The international cooperative study on the timing of aneurysm surgery. Part 2: surgical results. J Neurosurg. 1990;73(1):37-47. 8. Hunt WE, Hess RM. Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg. 1968;28(1):14-20. 9. Malek AM, Halbach W, Phatouros CC, et al. Spinal dural arteriovenous fistula with an associated feeding artery aneurysm: case report. Neurosurgery. 1999;44(4):877-880. 10. Kim DJ, Willinsky R, Geibprasert S, et al. Angiographic characteristics and treatment of cervical spinal dural arteriovenous shunts. Am J Neuroradiol. 2010;31(8):1512-1515. 11. Kawamura S, Yoshida T, Nonoyama Y, Yamada M, Suzuki A, Yasui N. Ruptured anterior spinal artery aneurysm: a case report. Surg Neurol. 1999;51(6):608-612. 12. Saunders FW, Birchard D, Willmer J. Spinal artery aneurysm. Surg Neurol. 1987;27(3):269-272. NEUROSURGERY COMMENT T he authors present an interesting case of spinal dural arteriovenous fistula (SDAVF) presenting with intracranial subarachnoid (SAH) and cervical spinal subdural hemorrhage (SDH). In and of itself, SAH is a rare presenting symptom for SDAVF, although recently a clinical series from Toronto reported a relatively high incidence of hemorrhagic presentation of cervical DAVFs (Kim et al, AJNR 2010;31:1512-1515). Feeding artery aneurysms to a SDAVF have been reported previously by UCSF (Malek et al, Neurosurgery 1999;44:877-880), with pathologic correlation. The current case report also offers pathology confirming a true arterial aneurysm as opposed to a dissection or mycotic aneurysm. This case underscores the importance of performing complete cervicocerebral angiography in order to delineate all possible feeding arteries to cervical spinal AV fistulas. Detailed angiography is essential prior to either endovascular or surgical treatment of these rare but important vascular malformations so that all arterial feeders to the AVF are identified as well as the pial supply to the spinal cord itself. Steven W. Hetts San Francisco, California VOLUME 70 | NUMBER 1 | JANUARY 2012 | E263 Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited.