Ruptured isolated spinal artery aneurysms: Case series of five patients and a review of the literature on management strategies.

BACKGROUND: Aneurysms of the spinal arteries are rare entities, the majority of which are associated with other vascular lesions, such as spinal vascular malformations. Isolated spinal artery aneurysms (SAAs) are even less frequently encountered, and their incidence is largely unknown, as the literature is limited to case reports and small series. The optimal management strategy for SAAs is not well defined. OBJECTIVE: To review the institutional experience of five patients with isolated SAAs. METHODS: Five cases of isolated SAAs were identified at our institution, including two cases with multiple simultaneous SAAs. Clinical presentation, imaging, and management strategies for each case were reviewed. A literature review of all SAAs reported between 1950 and 2020 was performed. RESULTS: A total of five patients with eight isolated SAAs presented to our institution: one aneurysm was lumbar in location, while the remaining seven were thoracic. Two patients were treated with glue embolization followed by laminectomy for hematoma evacuation; one was treated with only surgery; and the other two, which both had multiple lesions, were managed conservatively with interval complete regression of their aneurysms. All five patients had good neurological outcomes. Literature review found 124 patients with at least 137 isolated SAAs and revealed treatment strategies including conservative management, glue or coil embolization, muslin wrapping, and surgical resection or clipping. CONCLUSION: Multiple management strategies exist for SAAs, and clinical consideration of patient presentation and lesion morphology determine appropriate strategy. Our case series demonstrates three of these treatment paradigms.

Filum Terminale Arteriovenous Fistula with Additional Arterial Supply by the Posterior Spinal Artery: A Report of Two Cases.

Filum terminale arteriovenous fistulas (FTAVFs) are rare and usually supplied by the artery of the filum terminale, distal termination of the anterior spinal artery (ASA). These fistulas may also supply from the lateral sacral artery (LSA) arising from the internal iliac artery and/or middle sacral artery. Additional supply by the posterior spinal artery (PSA) has never been mentioned before. The authors describe two middle-aged men harboring FTAVFs manifested with progressive myelopathy and bowel/bladder dysfunction. The first fistula was supplied by the ASA with additional supply by the dilated PSA connecting with the ASA. Another fistula was supplied by the LSA and the PSA communicating with the ASA. The first case was successfully treated by endovascular treatment with N-butyl cyanoacrylate through the enlarged PSA, whereas the second case was surgically treated by direct obliteration of the fistula. Both patients had good neurological outcome.

Anatomical Study of the Posterior Spinal Artery Branches to the Medulla Oblongata.

BACKGROUND: The posterior spinal arteries (PSAs), branches of the intracranial segment of the vertebral artery or posterior inferior cerebellar artery, run bilaterally along the spinal cord and are integral to the blood supply primarily to the posterior one third of this structure. However, a less well-described distribution of the PSAs is their supply to the posterior medulla. The purpose of this study is to examine the medullary branches of the PSA anatomically. METHODS: We conducted a cadaveric study to evaluate for branches of the PSA supplying the medulla oblongata. RESULTS: All 14 sides had medullary branches arising from the PSAs. The average number of branches supplying the medulla oblongata on each side was 6. Most of these branches traveled laterally to anastomose with medullary branches arising from the anterior spinal artery. Additionally, lateral and ascending branches were noted. CONCLUSIONS: Physicians who interpret imaging of the craniocervical junction, in particular arteriograms, should be aware of ascending medullary branches arising from the anterior spinal artery. Additionally, neurosurgeons operating this region must be careful in dissecting over the posterior medulla and manipulating the cerebellar tonsils, as in telovelar approaches to the fourth ventricle, in order to avoid iatrogenic injury to these vessels. Additionally, variable stroke patterns involving the vertebral artery or posterior inferior cerebellar artery might include ischemia to the medulla oblongata via PSA branches, and this anatomy should be kept in mind by interventionalists, radiologists, and neurologists alike.

Posterior spinal artery aneurysm as an unlikely culprit for perimesencephalic pattern subarachnoid hemorrhage: illustrative case.

BACKGROUND: Angiogram-negative nontraumatic subarachnoid hemorrhage (SAH) can be diagnostically challenging, and a broad differential diagnosis must be considered. Particular attention to initial radiographic hemorrhage distribution is essential to guide adjunctive investigations. Posterior spinal artery aneurysms are rare clinical entities with few reported cases in the literature. An understanding of isolated spinal artery aneurysm natural history, diagnosis, and management is evolving as more cases are identified. OBSERVATIONS: Isolated thoracic posterior spinal artery aneurysm can be the culprit lesion in perimesencephalic distribution SAH. Embolization resulted in complete aneurysm occlusion and did not result in periprocedural morbidity. At the 1-year follow-up, the patient was neurologically intact with no recurrence on magnetic resonance angiography. LESSONS: This case report highlighted the presentation, diagnostic workup, clinical decision-making, and endovascular intervention for a woman who presented with SAH secondary to posterior spinal artery aneurysm. After initially negative results on vascular imaging, dedicated spinal vascular imaging revealed the location of the aneurysm. Multiple treatment modalities exist for isolated spinal artery aneurysms and must be selected on the basis of patient- and lesion-specific characteristics.

Intradural lumbar radicular arteriovenous malformation mimicking perimedullary arteriovenous malformation of the conus medullaris: illustrative case.

BACKGROUND: Intradural radicular arteriovenous malformation (AVM) of the cauda equina is a rare entity of spinal AVMs. Because of the specific arterial supply of the conus medullaris and cauda equina, AVMs in this area sometimes present with confusing radiological features. OBSERVATIONS: The authors reported a rare case of intradural radicular AVM arising from the lumbar posterior root. The patient presented with urinary symptoms with multiple flow void around the conus medullaris, as shown on magnetic resonance imaging. Digital subtraction angiography demonstrated arteriovenous shunt at the left side of the conus medullaris fed by the anterior spinal artery via anastomotic channel to the posterior spinal artery and rich perimedullary drainers. There was another arteriovenous shunt at the L3 level from the left L4 radicular artery. Preoperative diagnosis was perimedullary AVM with radicular arteriovenous fistula. Direct surgery with indocyanine green angiography revealed that the actual arteriovenous shunt was located at the left L4 posterior root. The AVM was successfully treated by coagulation of feeding branches. LESSONS: Unilateral arteriovenous shunt fed by either posterior or anterior spinal artery at the conus medullaris may include AVM of the cauda equina despite abundant perimedullary venous drainage. Careful pre- and intraoperative diagnostic imaging is necessary for appropriate treatment.

Neurovascular anatomy: Spine.

The arterial supply of the spinal cord is provided by the spinal branch of the cervical, thoracic, and lumbar intersegmental arteries. While supply is initially provided at each embryonic segment, only a few prominent anterior radiculomedullary arteries remain at the adult stage, including the arteries of the cervical and lumbosacral enlargements as well as a constant upper thoracic contributor. The spinal cord is surrounded by the vasocorona, an arterial network that includes several longitudinal anastomotic chains, notably the anterior and posterior spinal arteries, which respectively supply the central and peripheral components of the intrinsic vascularization. The intrinsic venous circulation is also divided into central and peripheral components. The perimedullary venous system includes several longitudinal anastomotic chains interconnected by the coronary plexus. The radiculomedullary veins loosely follow the spinal nerve roots on their way to the epidural plexus. Their point of passage through the thecal sac forms an important valve-like structure, the antireflux mechanism.

Spinal neurovascular complications with anterior thoracolumbar spine surgery: a systematic review and review of thoracolumbar vascular anatomy.

OBJECTIVE: Spinal cord infarction due to interruption of the spinal vascular supply during anterior thoracolumbar surgery is a rare but devastating complication. Here, the authors sought to summarize the data on this complication in terms of its incidence, risk factors, and operative considerations. They also sought to summarize the relevant spinal vascular anatomy. METHODS: They performed a systematic literature review of the PubMed, Scopus, and Embase databases to identify reports of spinal cord vascular injury related to anterior thoracolumbar spine procedures as well as operative adjuncts and considerations related to management of the segmental artery ligation during such anterior procedures. Titles and abstracts were screened, and studies meeting inclusion criteria were reviewed in full. RESULTS: Of 1200 articles identified on the initial screening, 16 met the inclusion criteria and consisted of 2 prospective cohort studies, 10 retrospective cohort studies, and 4 case reports. Four studies reported on the incidence of spinal cord ischemia with anterior thoracolumbar surgery, which ranged from 0% to 0.75%. Eight studies presented patient-level data for 13 cases of spinal cord ischemia after anterior thoracolumbar spine surgery. Proposed risk factors for vasculogenic spinal injury with anterior thoracolumbar surgery included hyperkyphosis, prior spinal deformity surgery, combined anterior-posterior procedures, left-sided approaches, operating on the concavity side of a scoliotic curve, and intra- or postoperative hypotension. In addition, eight studies analyzed operative considerations to reduce spinal cord ischemic complications in anterior thoracolumbar surgery, including intraoperative neuromonitoring and preoperative spinal angiography. CONCLUSIONS: While spinal cord infarction related to anterior thoracolumbar surgery is rare, it warrants proper consideration in the pre-, intra-, and postoperative periods. The spine surgeon must be aware of the relevant risk factors as well as the pre- and intraoperative adjuncts that can minimize these risks. Most importantly, an understanding of the relevant spinal vascular anatomy is critical to minimizing the risks associated with anterior thoracolumbar spine surgery.

Cervical Posterior Spinal Artery Syndrome Caused By Spontaneous Vertebral Artery Dissection: Two Case Reports and Literature Review.

Herein, we described 2 patients with posterior spinal artery syndrome (PSAS) caused by vertebral artery dissection. The patients complained of sudden neck pain or walking instability. Neurological examination revealed sensory loss, muscle weakness, and sensory ataxia. Angiography showed double lumen sign or intimal flap in the vertebral artery. T2-weighted imaging and diffusion-weighted imaging of MRI showed a hyperintense lesion in the dorsal side of the cervical spinal cord at different times after onset. Both patients had good outcome after antiplatelet therapy and physiotherapy. A review of previously reported PSAS cases was also conducted in order to improve the understanding and awareness of this rare myelopathy.

Isolated Posterior Spinal Artery Aneurysm Presenting with Spontaneous Thrombosis After Subarachnoid Hemorrhage.

BACKGROUND: The cause of subarachnoid hemorrhage is more likely to be intracranial than spinal. Bleeding, although common with spinal arteriovenous malformations and spinal cord tumors, rarely occurs with ruptured isolated spinal artery aneurysms. Here, we report a case of isolated thoracic posterior spinal artery aneurysm presenting with thrombosis after subarachnoid hemorrhage. CASE DESCRIPTION: A 67-year-old woman presented with sudden-onset nausea and low back and right thigh pain that worsened with movement. Computed tomography (CT) and magnetic resonance imaging (MRI) scans of the head suggested a small subarachnoid hemorrhage in the high-convexity sulcus, and lumbar puncture showed bloody cerebrospinal fluid. There was no apparent intracranial aneurysm on CT angiography; however, spinal MRI showed a lesion on the right side of the spinal cord at Th10. Contrast-enhanced CT showed an enhancing lesion at this site on day 7 that was not present on day 15. Selective right Th10 intercostal artery angiography on day 22 showed no evidence of aneurysm. The lesion was suspected to be a thrombotic spinal artery aneurysm. Given the unclear natural history of this entity, surgery was performed on day 36. After right Th10 hemilaminectomy and opening the dura, the arachnoid and adhesions were found to be thickened. A fusiform-shaped thrombosed aneurysm continuous with the radiculopial artery was removed. The patient was discharged without neurologic deterioration. CONCLUSIONS: Isolated spinal artery aneurysm is a rare cause of subarachnoid hemorrhage. It is expected that additional cases will clarify the natural history and indications for treatment.

Double Origin of the Posterior Inferior Cerebellar Artery: Anatomic Case Report.

BACKGROUND: Double origin of the posterior inferior cerebellar artery is rare. It has important clinical implications especially in cases of aneurysms of the vertebral artery or the posterior inferior cerebellar artery. Several radiologic reports of this variant exist. However, no anatomic illustration of this rarity exists in the literature. This brief report provides the first anatomic illustration of this important variation of the vertebrobasilar system. CASE DESCRIPTION: A cadaveric specimen was prepared for dissection. A far lateral craniotomy was performed on the right side. While exploring the right cerebellomedullary cistern, 2 separate origins of the posterior inferior cerebellar artery were found from the vertebral artery as the caudal and rostral trunks that joined to form the distal posterior inferior cerebellar artery trunk at the tonsillomedullary segment. Microscopic and endoscopic illustrations are provided. CONCLUSIONS: To the best of our knowledge, this is the first anatomic report on the double origin of the posterior inferior cerebellar artery. Cadaveric illustration of this variant helps with understanding its anatomic relationship with adjacent neurovascular structures of the cerebellomedullary cistern including the perforating arteries and the lower cranial nerves.

The V3 segment of the vertebral artery as a robust donor for intracranial-to-intracranial interpositional bypasses: technique and application in 5 patients.

The V3 segment of the vertebral artery (VA) has been studied in various clinical scenarios, such as in tumors of the craniovertebral junction and dissecting aneurysms. However, its use as a donor artery in cerebral revascularization procedures has not been extensively studied. In this report, the authors summarize their clinical experience in cerebral revascularization procedures using the V3 segment as a donor. A brief anatomical description of the relevant techniques is also provided.

Conus Medullaris Syndrome Due to Posterior Spinal Artery Infarction

A 77-year-old female with a history of osteoarthritis visited our clinic complaining of lower back pain, paresthesia in both legs, and voiding difficulty. Her pain and temperature sensations were diminished below the L1 dermatome, and proprioception was decreased in both feet. The findings of a routine laboratory workup, echocardiogram, and cerebrospinal fluid studies were normal. Spine magnetic resonance imaging revealed high T2-weighted signal intensities and diffusion restriction in the posterior conus medullaris. The patient was diagnosed and treated for posterior spinal artery infarction.

Rare spinal cord infarction in a patient with acute type B aortic dissection.

A 69-year-old man was admitted to our hospital with acute epigastric discomfort and subsequent paraplegia. Computed tomography revealed acute type B aortic dissection with a thrombosed false lumen. Magnetic resonance imaging did not reveal spinal cord infarction. Paraplegia resolved completely within 1 h. However, on the following day, the patient developed motor impairment in the left leg, sensory disorder of the bilateral legs and urinary retention. The symptoms gradually improved with conservative medical therapy. Magnetic resonance imaging on hospitalization Day 20 revealed spinal cord infarction limited to the right posterior area at level T7/T8 and the conus medullaris. The patient was discharged 44 days after admission. The presented case is notable for its atypical presentation of spinal cord infarction resulting from acute aortic dissection. The aetiology of neurological symptoms, especially that of lower extremity monoplegia, remained undiagnosed.

Electrophysiological monitoring during preoperative angiography to guide decisions regarding permanent occlusion of major radicular arteries in patients undergoing total en bloc spondylectomy.

OBJECTIVE Preoperative embolization is performed before spine tumor surgery when significant intraoperative hemorrhage is anticipated. Occlusion of radicular and segmental arteries may result in spinal ischemia. The goal of this study was to check whether neurophysiological monitoring during preoperative angiography in patients scheduled for total en bloc spondylectomy (TES) of spine tumors improves the safety of vessel occlusion. METHODS This was a case series study of patients who underwent tumor embolization under somatosensory evoked potential (SSEP) and motor evoked potential (MEP) monitoring in preparation for TES in treating spine tumors. The angiography findings, the embolized vessels, and the results are presented. RESULTS Five patients whose ages ranged from 33 to 75 years and who had thoracic spine tumors are reported. Four patients suffered from primary tumor and 1 patient had a metastatic tumor. Radicular arteries at the tumor level, 1 level above, and 1 level below were permanently occluded when SSEPs and MEPs were preserved during temporary occlusion. No complications were encountered during or after the angiography procedure and embolization. CONCLUSIONS Temporary occlusion with electrophysiological monitoring during preoperative angiography may improve the safety of permanent radicular artery occlusion, including the artery of Adamkiewicz in patients undergoing TES for the treatment of spine tumors.

Posterior Spinal Artery Aneurysm Presenting with Leukocytoclastic Vasculitis.

Rupture of isolated posterior spinal artery (PSA) aneurysms is a rare cause of subarachnoid hemorrhage (SAH) that presents unique diagnostic challenges owing to a nuanced clinical presentation. Here, we report on the diagnosis and management of the first known case of an isolated PSA aneurysm in the context of leukocytoclastic vasculitis. A 53-year-old male presented to an outside institution with acute bilateral lower extremity paralysis 9 days after admission for recurrent cellulitis. Early magnetic resonance imaging was read as negative and repeat imaging 15 days after presentation revealed SAH and a compressive spinal subdural hematoma. Angiography identified a PSA aneurysm at T9, as well as other areas suspicious for inflammatory or post-hemorrhagic reactive changes. The patient underwent a multilevel laminectomy for clot evacuation and aneurysm resection to prevent future hemorrhage and to establish a diagnosis. The postoperative course was complicated by medical issues and led to the diagnosis of leukocytoclastic vasculitis that may have predisposed the patient to aneurysm development. Literature review reveals greater mortality for cervical lesions than thoracolumbar lesions and that the presence of meningitic symptoms portents better functional outcome than symptoms of cord compression. The outcome obtained in this case is consistent with outcomes reported in the literature.

Cervical Posterior Spinal Artery Syndrome: A Case Report and Literature Review.

We report a case of left upper cervical posterior spinal artery (PSA) syndrome caused by atherosclerosis of the left vertebral artery. A 70-year-old female experienced sudden dizziness and paralysis of the left upper and lower limbs. Diffusion-weighted magnetic resonance imaging (DWI) of the brain showed high signal intensity at the vermis and lower left hemisphere of the cerebellum, and magnetic resonance angiography showed that the entire left vertebral artery was thin. The patient was treated with an intravenous infusion of tissue plasminogen activator 2 hours after symptom onset and made a full recovery. Repeat DWI, fluid-attenuated inversion recovery images, and T2-weighted images showed high signal intensity in the left upper cervical PSA area from the lower medulla oblongata to the C2 level in addition to the cerebellum. Previously reported cases of cervical posterior artery syndrome are reviewed.

Developmental anomalies of the distal vertebral artery and posterior inferior cerebellar artery: diagnosis by CT angiography and literature review.

PURPOSE: The aim of this study was to identify variations in the anatomy of the distal vertebral artery (VA) and posterior inferior cerebellar artery (PICA) with computed tomography (CT) angiography. METHODS: CT angiography was performed at two hospitals. And the results were analyzed for VA anomalies. RESULTS: Seven of the 3067 patients who received brain CT angiography in first hospital had seven intracranial VA fenestrations. Twelve of 546 patients who received CT angiography of intracranial and extracranial vessels in second hospital had 16 anatomical variations of the V3 segment. Two fenestrations of the V3 segment, three C1 origins of the PICA, seven aberrant VAs with an intradural course at the C2 level without a normal VA, and four aberrant VAs with an intradural course at the C2 level with a normal VA were observed. Seventeen of the 314 patients who received cervical CT angiography in second hospital had 21 anatomical variations of the VA. Two fenestrations of the V3 segment, six C1 origins of the PICA, three C2 origins of the PICA, one VA origin of the occipital artery, one fenestration of the V4 segment, five aberrant VAs with an intradural course at the C2 level without a normal VA, and three aberrant VAs with an intradural course at the C2 level with a normal VA were observed. CONCLUSIONS: A certain number of anatomical variants of the distal VA and PICA may reflect variations in size and connections of the lateral or posterior spinal artery.

Posterior Spinal Artery Aneurysm Presenting with Leukocytoclastic Vasculitis

Rupture of isolated posterior spinal artery (PSA) aneurysms is a rare cause of subarachnoid hemorrhage (SAH) that presents unique diagnostic challenges owing to a nuanced clinical presentation. Here, we report on the diagnosis and management of the first known case of an isolated PSA aneurysm in the context of leukocytoclastic vasculitis. A 53-year-old male presented to an outside institution with acute bilateral lower extremity paralysis 9 days after admission for recurrent cellulitis. Early magnetic resonance imaging was read as negative and repeat imaging 15 days after presentation revealed SAH and a compressive spinal subdural hematoma. Angiography identified a PSA aneurysm at T9, as well as other areas suspicious for inflammatory or post-hemorrhagic reactive changes. The patient underwent a multilevel laminectomy for clot evacuation and aneurysm resection to prevent future hemorrhage and to establish a diagnosis. The postoperative course was complicated by medical issues and led to the diagnosis of leukocytoclastic vasculitis that may have predisposed the patient to aneurysm development. Literature review reveals greater mortality for cervical lesions than thoracolumbar lesions and that the presence of meningitic symptoms portents better functional outcome than symptoms of cord compression. The outcome obtained in this case is consistent with outcomes reported in the literature.