Spinal arteriovenous metameric syndrome: clinical manifestations and endovascular management

Arteriovenous shunts of the cervical spine: patient demographics, presentation, patterns of high-risk venous drainage, and updated classification

BACKGROUND

Intracranial dural arteriovenous (AV) fistula classifications focus on presence/absence of retrograde flow in the cortical veins of the brain as this angiographic finding portends a worse prognosis. However, prior categorization systems of AV shunts in the spine do not incorporate these features. We propose an updated classification for spinal shunting lesions that terms any shunting lesion with retrograde flow in any cortical vein of the brain or spinal cord medullary vein as "high risk". To present this classification, we analyzed our center's most recent experience with cervical spine shunting lesions.

METHODS

The electronic medical record at our institution was reviewed to identify shunting lesions of the cervical spine and patient demographics/presentation. Comprehensive craniospinal digital subtraction angiograms were evaluated to classify shunt location, type (arteriovenous malformation (AVM) vs arteriovenous fistula (AVF)), and presence of high-risk venous drainage.

RESULTS

Some 52 lesions were identified and categorized as pial/dural/epidural/paravertebral AVFs and intramedullary/extraspinal AVMs. Lesions were classified as high risk or not depending on the presence of retrograde flow into at least one vein that directly drains the spinal cord or brain. All patients who presented with either hemorrhage or infarct had underlying high-risk lesions. Additionally, 50% (17/34) of symptomatic patients with high-risk lesions presented with neurological extremity symptoms (OR=10.0, p=0.037) most of which fit a myelopathic pattern.

CONCLUSION

We present an updated classification system for shunting lesions of the spine that focuses on high-risk retrograde flow to the brain or spine in addition to anatomical location in order to better inform patient management.

Perioperative Management of Spinal Arteriovenous Malformation Embolization: Delayed Venous Thrombosis and Implications for Severe Back Pain

BACKGROUND AND PURPOSE

The prognosis of untreated spinal arteriovenous malformations (SAVMs) is poor. Embolization plays an important role in the management of intramedullary SAVMs. Delayed aggravation due to spinal venous thrombosis following successful embolization has been reported; however, perioperative management strategies to prevent thrombosis have not been explored. We present our single-center experience of SAVM embolization and perioperative management, including anticoagulation.

MATERIAL AND METHODS

We retrospectively evaluated 18 patients with SAVMs who underwent transarterial embolization. Perioperative anticoagulation therapy was administered to selected patients. We compared the characteristics of the patients, including perioperative management procedures, between those with and without postoperative worsening following embolization.

RESULTS

Acute postoperative worsening within 1 week occurred in 4 (22.2%) patients. Of these, immediate worsening was observed in one patient as a procedure-related complication. Delayed worsening after 24 h was observed in 3 patients, caused by delayed venous thrombosis with severe back pain. Rescue anticoagulation for delayed worsening improved symptoms in two patients. A comparison between patients with and without acute postoperative worsening revealed significant differences in age (median 46.5 vs. 26.5 years, p = 0.009) and the presence of postoperative back pain (75.0% vs. 0%, p = 0.005); however, there was no significant difference in use of selective anticoagulation (p = 0.274).

CONCLUSION

The results of this study suggest that SAVM embolization can cause acute worsening due to postoperative venous thrombosis with severe back pain, which may be reversed by anticoagulation therapy. Back pain is an important finding that suggests venous thrombosis, and anticoagulation should be urgently administered.

Recurrent Spinal Arteriovenous Malformations in a Patient with Cobb Syndrome

Cobb syndrome is a rare neurocutaneous disease characterized by multiple spinal vascular anomalies and vascular skin lesions affecting the corresponding dermatome. We present a case of a 12-year-old boy with history of spinal arteriovenous malformation (AVM) extending from T4-T5 status post partial embolization 3 years ago and hyperpigmented patch overlying his thoracic back region presenting with 2 days of back pain and lower extremity numbness and weakness. He had multiple Type III AVMs within the spinal and paraspinal tissues involving the T4-T7 vertebral elements, most extensively T4 and T5. The largest aneurysm located at the confluence of the main AVM nidus was a 4 mm anterior spinal artery aneurysm, which was embolized with partial embolization of the main AVM nidus, resulting in complete aneurysm occlusion. This report provides valuable insight on the natural history, recurrence risk, and treatment options of Cobb syndrome to aid in early diagnosis and improve outcomes.

Malignancy-related Hypercalcemia Caused by Metameric Cutaneous Metastasis of Parathyroid Hormone-related Protein-producing Bladder Carcinoma with Squamous Cell Differentiation: An Autopsy Case of Cobb Syndrome

A 74-year-old woman was admitted with hypercalcemia and prolonged disturbance of consciousness. The left buttock to the anterior aspect of the left thigh was swollen and erythematous, with a collection of 1.0-cm large, firm, elastic nodules distributed in a zosteriform pattern in the L1-L4 region. Based on autopsy findings, a very rare case of Cobb syndrome was diagnosed due to a spinal vascular malformation at the Th12-L4 level and L5 vertebral hemangioma. Cobb syndrome-associated cutaneous metastasis extending along the same metamere was complicated by immunohistochemically proven parathyroid hormone-related protein-producing advanced bladder carcinoma in this case.

Targeted embolisation for coexisting conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas with a varix on a shared drainer†

BACKGROUND

The coexistence of vascular malformations in the conus medullaris and cauda equina has been rarely reported, and the complex angioarchitecture in multiple arteriovenous lesions remains poorly understood.

CASE DESCRIPTION

A 17-year-old woman presented with a sudden-onset, stepwise worsening of weakness and pain in the bilateral legs. Angiography revealed conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas. One of the drainers was shared between the coexisting lesions and harboured a varix. Targeted embolisation of a fistulous point in the conus lesion was performed with precaution to prevent occluding the common drainage route, which led to symptom improvement with angiographical diminishment of the varix.

CONCLUSIONS

Recognising that communications between drainers can be observed in multiple spinal arteriovenous lesions is important in facilitating a safe embolisation. Cautious assessment of angiogram with fusion images of cone-beam computed tomography and volumetric T2 magnetic resonance imaging can help in establishing the diagnosis and treatment strategy.

Spontaneous regression of extradural high-flow vascular malformation in spinal arteriovenous metameric syndrome (SAMS): A unique case report

Background

Spinal arteriovenous metameric syndrome (SAMS) is a rare nonhereditary genetic vascular disorder, involving multiple layers of tissues in the same metameric level. Spontaneous regression of SAMS has never been reported in the medical literature.

Case Description

A 42-year-old woman presented with intermittent low back pain for 6 months. Magnetic resonance imaging of the thoracolumbar spine incidentally found clusters of spinal vascular malformations involving spinal cord, vertebral bodies, epidural space, and paraspinal muscles. There was no sign of venous congestion. Magnetic resonance angiography and spinal angiography revealed intradural spinal cord arteriovenous malformation (SCAVM) at the level of T10-11 and extradural high-flow osseous arteriovenous fistula. Due to asymptomatic SAMS and a high risk of anterior spinal arterial compromise during treatment, conservative treatment was considered in our patient. Spinal angiography obtained 8 years after initial angiography demonstrated significant regression of extradural component of SAMS and stable intradural SCAVM.

Conclusion

We describe a unique case of SAMS with spontaneous regression of extradural component during a long-term observation period.

Postsurgical dural supply to the spinal cord arteriovenous malformation in spinal arteriovenous metameric syndrome

Dural supply from the external carotid system in cerebral arteriovenous malformations (AVMs) is well known, but actual angiographic evidence of dural supply to spinal cord AVMs (SCAVMs) has not been reported. Here, we report a case of dural supply to the conus SCAVM in the spinal arteriovenous metameric syndrome segment 25-30. Thirteen years after spinal surgery (T12-L2 laminoplasty), spinal angiography showed multiple dural supplies from the dorsal somatic branches, prelaminar arteries, and radiculomeningeal arteries to the SCAVM at the level of the previous spinal surgery. To the best of our knowledge, this is the first reported case with dural supply to the spinal cord. This case demonstrates that the extradural and extraspinal branches can supply the spinal cord in rare instances of spinal dural adhesions following repeated hemorrhages and surgical intervention under a metameric link background.

Spinal intraosseous arteriovenous fistulas with perimedullary drainage associated with vertebral compression fracture: illustrative case

BACKGROUND

Although osseous involvement is occasionally observed in spinal epidural arteriovenous fistulas (AVFs) or seen as a part of diseases of spinal arteriovenous metameric syndrome, purely intraosseous spinal AVFs are extremely rare. Their clinical and imaging characteristic features are not well known. The authors present a case of purely intraosseous AVFs associated with compression fracture.

OBSERVATIONS

A 76-year-old man presented with back pain and progressive myelopathy. Computed tomography showed compression fracture of the T12 vertebral body and dilatation of perimedullary veins. Spinal angiography revealed an intraosseous AVF at the T12 spine level, which was fed by multiple feeders of ventral somatic branches and drained into the paravertebral and perimedullary veins. The intraosseous AVF was completely occluded by the combined techniques of transarterial and transvenous embolization with glue and a coil. The symptoms disappeared within 1 month after embolization.

LESSONS

Although extremely rare, spinal intraosseous AVFs can develop after compression fracture and cause congestive myelopathy. Combined transarterial and transvenous embolization is useful for the specific case of spinal intraosseous AVFs with both paravertebral and perimedullary drainage.

Clinical features and outcomes of perimedullary arteriovenous fistulas: comparison between micro- and macro-type lesions

BACKGROUND

Although the angioarchitecture of perimedullary arteriovenous fistulas (PMAVFs) is straightforward, their size and blood flow are highly heterogeneous. This study aimed to evaluate the differences in clinical features and outcomes of PMAVFs based on lesion size and blood flow.

METHODS

114 consecutive patients with PMAVFs from two institutes were retrospectively reviewed. The lesions were classified as either micro-PMAVFs (shunt point diameter <1 cm) or macro-PMAVFs (shunt point diameter ≥1 cm).

RESULTS

The patients with micro-PMAVFs were older at the first presentation (33.50 vs 13.50 years, p<0.001). Macro-PMAVFs were more commonly associated with spinal metameric arteriovenous shunts (6.9% vs 28.6%, p=0.003). Compared with the macro-PMAVFs, the micro-PMAVFs showed a significantly higher risk of gradual clinical deterioration after initial onset (73.6%/year vs 10.0%/year; HR 3.888, 95% CI 1.802 to 8.390, p=0.001). A total of 58.6% of the micro-PMAVFs were treated surgically, whereas 85.7% of the macro-PMAVFs were treated via endovascular approaches. Complete obliteration was 73.7% for the whole cohort, and was more common for the micro-PMAVFs than for the macro-PMAVFs (87.9% vs 58.9%, p=0.001). At the last follow-up, spinal function was significantly improved compared with the pretreatment status, and the rate of severe disability of patients with macro-PMAVFs was slightly but not significantly higher than that of patients with micro-PMAVFs (16.1% vs 8.6%, p=0.315) CONCLUSIONS: The clinical risks, treatment strategies and obliteration rates of PMAVFs differ based on their size and blood flow.

Treatment of Spinal Arteriovenous Malformation and Fistula

With the rapid advancements in endovascular therapy over previous decades, the treatment of spinal arteriovenous malformations (AVMs) continues to evolve. The decision to use endovascular versus surgical therapy largely depends on the type of lesion and its anatomic location. Recent studies demonstrate that endovascular treatment is effective for extradural arteriovenous fistulas (AVFs), intradural ventral (perimedullary) AVMs, and intramedullary spinal AVMs. Treatment of intradural dorsal (dural) AVFs remains largely surgical because of lower recurrence rates, although recent studies demonstrate equivocal outcomes. Extradural-intradural (juvenile) AVMs and conus AVMs remain difficult-to-treat lesions.

Combined endovascular and surgical management of a case of Cobb syndrome

Cobb syndrome is a rare neurocutaneous disorder characterised by spinal and cutaneous vascular malformations in a metameric distribution. Managing such cases is a challenge for the interventionists and neurosurgeons as the results are often suboptimal. We describe a case of Cobb syndrome in a young male child who presented clinically with acute paraparesis and lower backache. On radiological workup, an intradural perimedullary complex spinal arteriovenous fistula was seen with presence of subarachnoid haemorrhage in the spinal canal and compressive myelopathy. There was a haemangioma in paraspinal muscles and a maculopapular cutaneous lesion in the lower back. He was treated with combined endovascular embolisation and surgical intervention and showed significant clinical improvement on follow-up.

The efficacy and deficiency of contemporary treatment for spinal cord arteriovenous shunts

Contemporary treatments for spinal cord arteriovenous shunts are only based on clinicians' treatment experiences and expertise due to its rarity. We reviewed the clinical course of the largest multi-cantered cohort to evaluate the efficacy and deficiency of contemporary interventional treatments for spinal cord arteriovenous shunts. The clinical features, treatment results and clinical outcomes of 463 spinal cord arteriovenous shunts patients were retrospectively assessed. The main outcome was the neurological deterioration that was evaluated based on the modified Aminoff and Logue scale. According to post-treatment DSA, complete obliteration was defined as disappearance of the intradural lesion, whereas partial obliteration was defined as any residual intradural lesion remaining visible and was further categorized as shunt-reduction obliteration (the nidus or shunt points was reduced) or palliative obliteration (only obliterated aneurysms or feeders). Cure rate was 40.6% for whole cohort, 58.5% after microsurgery, and 26.4% after embolization. The curative resection was associated with non-metameric lesions, lesions with a maximum diameter < 3 cm and lesions without anterior sulcal artery supply. The curative embolization was associated with fistula-type lesions, non-metameric lesions, and main drainage diameter < 1.5 mm. Permanent treatment-related neurological deficits rate was 11.2% for the whole cohort, 16.1% after microsurgery, and 5.6% after embolization. The pre-treatment clinical deterioration rate was 32.5%/year, which decreased to 9.3%/year after clinical interventions. After partial treatment, the long-term acute and gradual deterioration rate were 5.3%/year and 3.6%/year, respectively. The acute deteriorations were associated with metameric lesions, craniocervical lesions, lesions with a maximum diameter ≥2 cm and residual aneurysm. Residual aneurysm was the only predictor of acute deterioration for non-metameric spinal cord arteriovenous shunts. The gradual deteriorations were associated with palliative obliteration, absence of pre-treatment acute deterioration and intact main drainage. Although clinical risks of spinal cord arteriovenous shunts were reduced after clinical interventions, contemporary treatments for spinal cord arteriovenous shunt remains associated with considerable risks and incomplete efficacy. Individualized treatment plans should be adopted according to the angioarchitectural features and major clinical risks of specific lesions. There is a higher opportunity for complete obliteration for lesions with simple angioarchitecture. However, regarding most of spinal cord arteriovenous shunts with complex vascular anatomy, partial treatment is the only choice. For these patients, palliative obliteration targeting the aneurysms is recommended for reducing hemorrhagic risk, whereas shunt-reduction obliteration is necessary for non-haemorrhagic myelopathy. Contemporary treatment is ineffective in reducing hemorrhagic risk of incurable metameric spinal cord arteriovenous shunts.

Spontaneous closure of an incidental high-flow paravertebral arteriovenous fistula caused by vertebral giant cell tumor curettage: illustrative case

BACKGROUND

Paravertebral arteriovenous fistula (AVF) after spinal surgery is rarely reported in the literature. Its natural course is largely unknown.

OBSERVATIONS

The authors report a 31-year-old woman with a high-flow AVF after T12 vertebral giant cell tumor curettage. Eight months after the initial surgery, revision en bloc surgery was planned. Preoperative computed tomography angiography was performed for vascularity assessment, which incidentally revealed a large paravertebral early-enhanced venous sac. High-flow AVF was confirmed through subsequent spinal angiography. Endovascular embolization was scheduled before the surgery to avoid massive blood loss. However, the AVF closed spontaneously 1 month after the spinal angiography. The plan was changed to preoperative embolization; subsequently, three-level en bloc spondylectomy was performed smoothly.

LESSONS

Iatrogenic AVF is possible, prompting investigation by vascular imaging when suspected. Embolization is a preferred treatment method when feasible. However, for iatrogenic etiology, the prothrombotic property of the contrast medium may induce the resolution. Multidisciplinary discussion can be very helpful before aggressive spinal surgery.

Intradural spinal cord arteriovenous shunts in a personal series of 210 patients: novel classification with emphasis on anatomical disposition and angioarchitectonic distribution, related to spinal cord histogenetic units

OBJECTIVE

Few classifications of intradural spinal arteriovenous shunts (ID-SAVSs) have considered their anatomical localization in relation to their phenotype and angioarchitectonics. The authors propose another vision of ID-SAVSs allowing a reappraised classification based on analysis of the anatomical disposition, angioarchitecture, and histogenetic location of these vascular malformations.

METHODS

The radiological and clinical records of 210 patients with ID-SAVSs were retrospectively reviewed, considering their localization, vascular architectonics, and correlation with the 5 histogenetic units of the spinal cord. Among these, 183 files with complete data allowed precise analysis of the ID-SAVSs.

RESULTS

Among these 183 files (162 and 21 cases with single and multiple lesions, respectively), different entities were identified: 13 pial macro arteriovenous fistulas (MAVFs), 92 pial micro arteriovenous fistulas (mAVFs), 33 superficial pial niduses, and 69 intramedullary niduses. Thirteen sulcal shunts (either fistulas or niduses) were considered subtypes of pial lesions. Among the 21 multiple cases, 11 were monomyelomeric while 10 were multimyelomeric. Pial lesions, either fistulas or niduses, were dominantly vascularized by pial arteries (anterior or posterior depending on the localization of the shunt) and occasionally (except for MAVFs) by transmedullary arteries. Pial niduses occasionally extended into the funiculus by recruiting intrinsic veins or by extension of the nidus itself inside the white matter. Intramedullary niduses were always vascularized by both centrifugal and centripetal feeders, respectively, from sulcal arteries (SAs) and pial arteries. Sulcal lesions are pial lesions located within the ventral median sulcus and vascularized by SAs and veins. Single or multiple ID-SAVSs can be part of various syndromes such as hereditary hemorrhagic telangiectasia, Parkes-Weber, RASA1, CLOVES, and spinal arteriovenous metameric syndromes. Histogenetic analyses revealed a specific distribution of each ID-SAVS in the 5 histogenetic units of the spinal cord: intramedullary niduses were found almost equally from cervical to thoracic units, while MAVFs and mAVFs were mostly found from thoracic to postcrural ones. Pial niduses showed intermediate features between intramedullary and fistulous lesions and were mostly distributed from brachial to crural segments.

CONCLUSIONS

Precise analysis of the anatomical disposition of ID-SAVSs in relation to functional histogenetic units allows a better understanding of these lesions and improved therapeutic management.

Endovascular Management of Type III Perimedullary Spinal Arteriovenous Malformations in Pediatric Population

BACKGROUND

Spinal arteriovenous malformations (AVMs) are a cause of 20-30 of all spinal vascular malformation. The treatment option for the AVM depends upon the type of AVM. Here, we present a case series to discuss the type, management, and post-operative conclusion of the spinal AVMs.

METHOD

Four patients with spinal AVMs were retrospectively reviewed. All 4 patients were with a nidus-type AVM. Treatment for all patients required embolization. Clinical features, imaging, treatment, and clinical results were observed. All 4 patient's clinical outcome was assessed using the Modified Ranked Scale.

RESULT

The follow-up after management showed that all four-patient recovered without any residual deficit. All four-patient scored zero (0) on the Modified Ranked Scale.

CONCLUSION

Pediatric spinal AVMs are rare and require complex multimodal approach to achieve favorable outcomes.

Anterior Spinal Artery Steal Syndrome Complicated by Ruptured Flow-Related Aneurysm of the Anterior Radiculomedullary Artery

BACKGROUND

Anterior spinal artery steal syndrome, radiculomedullary artery aneurysms, and pulmonary arteriovenous malformations with a systemic origin are each, considered individually, exceptional conditions.

CASE DESCRIPTION

We describe the coexistence of all these conditions and their pathophysiologic relationship by presenting the case of a woman who referred to the emergency department for loss of consciousness and a history of 2 days of medullary symptoms and a subsequent acute respiratory failure. Detailed imaging revealed a subarachnoid hemorrhage due to the rupture of a spinal aneurysm located in a C8 radiculomedullary artery that had its flow reversed toward the deep cervical artery from which a systemic to pulmonary arteriovenous malformation originated.

CONCLUSIONS

Eventually, the lesion was treated with the exclusion of the left C8 spinal segmental branch and embolization of the arteriovenous malformation.

Monitoring Arteriovenous Malformation Response to Genotype-Targeted Therapy

Arteriovenous malformations (AVMs) have recently been reported to have a high incidence of somatic KRAS mutations suggesting potential for treatment with mitogen-activated protein kinase inhibitors. In this case report, we describe genotype-targeted treatment of a KRAS mutant metameric AVM in a patient with Cobb syndrome using the mitogen-activated protein kinase inhibitor trametinib. Therapeutic response was monitored with phase-contrast magnetic resonance angiography to quantify AVM arterial inflow as an imaging biomarker. Treatment with trametinib resulted in a substantial decrease in blood flow to the AVM, with a >75% reduction in arterial inflow after 6 months of trametinib therapy.

Bilateral optic disc pits in a pediatric patient with Cobb syndrome

Purpose

To describe a patient with Cobb Syndrome, a rare congenital disorder characterized by cutaneous and spinal arteriovenous malformations, who was found to have bilateral optic nerve pits.

Observations

A 15-year-old boy diagnosed with Cobb Syndrome, manifesting as a large cutaneous port-wine stain associated with an underlying left paraspinous arteriovenous malformation resulting in severe scoliosis, presented for a screening ophthalmological exam. The patient had no visual symptoms. On examination, his visual acuity was 20/20 in each eye; however, bilateral optic disc pits were discovered on biomicroscopy and confirmed by spectral-domain optical coherence tomography.

Conclusion and importance

The unusual finding of bilateral optic disc pits in this rare congenital neurocutaneous disorder represents the first report of ophthalmic abnormalities in association with Cobb syndrome. Patients with Cobb Syndrome may be considered for screening ophthalmological exam for the detection of subclinical optic nerve abnormalities.

Metameric spinal AVM: Long-term symptomatic relief achieved by embolization of the extradural component

BACKGROUND

Metameric spinal cord arteriovenous malformations (AVMs) are rare lesions characterized by an intradural and extradural component. They are difficult to treat surgically by the endovascular route. We report a case in which symptomatic relief was achieved by embolization of the extradural component only.

CASE PRESENTATION

A 35-year-old woman presented with acute worsening of back pain, weakness in the left leg and urinary retention. Spinal angiography showed a metameric spinal cord AVM with partial common venous drainage of the extradural and intradural components.

CONCLUSIONS

Targeted embolization of the extradural component led to dramatic improvement of the patient's symptoms, probably by achieving venous decongestion. She remains neurologically stable at two years' follow-up.

Natural history of spinal cord arteriovenous shunts: an observational study

The natural history of intradural spinal cord arteriovenous shunts is unknown. We performed an observational study in a consecutive patient cohort with symptomatic intradural spinal cord arteriovenous shunts who were admitted to three institutes to investigate the clinical course of this complex disease, which would provide valuable evidence to inform clinical decision-making. The clinical course of patients with symptomatic intradural spinal cord arteriovenous shunts from initial presentation to occurrence of clinical deterioration, initiation of treatment, or last follow-up was analysed. Patients with at least 1 month of observation were included in this study. Clinical onset and deterioration patterns were divided into acute and gradual. Annual and cumulative rates of clinical deterioration as well as their risk factors were analysed using Kaplan-Meier life table analysis and Cox proportional hazards model. To assess risks and benefits of treatment, post-treatment clinical courses were further assessed. Four hundred and sixty-six patients with a mean observational period of 36.9 ± 58.8 months were included; 56.7% of patients presented with acute onset, of whom 77.3% experienced spontaneous recovery. Age of onset older than 28 years, initial modified Aminoff and Logue scale of >3, mid-thoracic lesions and non-ventral lesions were independent predictors of failure for spontaneous recovery. The annual risk of general, acute and gradual clinical deterioration after onset was 30.7%, 9.9% and 17.7%, respectively. Risk of deterioration was highest in the early period after initial onset. Acute onset was the only independent risk factor [hazard ratio 1.957 (95% confidence interval, CI 1.324–2.894); P = 0.0008] of acute deterioration and gradual onset was the strongest predictor [hazard ratio 2.350 (95% CI 1.711–3.229); P < 0.0001] of the gradual deterioration among all the stratifying factors. After invasive treatment, complete obliteration was achieved in 37.9% of patients (138 of 364) and improved or stable clinical status was noted in 80.8% of patients. Forty-two patients (11.5%) experienced permanent complications. Overall post-treatment deterioration rate was 8.4%/year, and 5.3%/year if permanent complications were excluded. The natural history of symptomatic spinal cord arteriovenous shunts is poor, especially in the early period after onset, and early intervention is thus recommended. Initial onset pattern significantly affects the natural history of the lesion, which prompts a differentiated treatment strategy.

The Rare Neurocutaneous Disorders: Update on Clinical, Molecular, and Neuroimaging Features

Phakomatoses, also known as neurocutaneous disorders, comprise a vast number of entities that predominantly affect structures originated from the ectoderm such as the central nervous system and the skin, but also the mesoderm, particularly the vascular system. Extensive literature exists about the most common phakomatoses, namely neurofibromatosis, tuberous sclerosis, von Hippel-Lindau and Sturge-Weber syndrome. However, recent developments in the understanding of the molecular underpinnings of less common phakomatoses have sparked interest in these disorders. In this article, we review the clinical features, current pathogenesis, and modern neuroimaging findings of melanophakomatoses, vascular phakomatoses, and other rare neurocutaneous syndromes that may also include tissue overgrowth or neoplastic predisposition.

Endovascular treatment of spinal arteriovenous malformations

Spinal arteriovenous malformations (AVMs) are a rare but treatable cause of myelopathy and spinal cord hemorrhage. The clinical presentation and ideal treatment of these lesions vary widely, primarily due to differences in anatomic and angioarchitectural features. Six well-defined types of fistula have been defined: (1) intradural dorsal AVM; (2) intramedullary AVM; (3) extradural-intradural AVM; (4) intradural ventral AVF; (5) extradural/epidural AVF; and (6) conus medullaris AVM. Each of these lesions have unique clinical presentations and variable natural histories and endovascular treatment options. The principles of endovascular treatment include: (1) a complete understanding of the angioarchitecture and anatomic features of the lesion, including identification of radiculomedullary arteries; (2) careful spinal angiography; (3) identification of treatment goals prior to the procedure (i.e., complete occlusion versus partial occlusion aimed at altering natural history); (4) selection of proper embolic agent; and (5) careful follow-up in both the immediate postoperative setting and long term.

The Coexistence of Extradural Arteriovenous Fistula and Soft Tissue Arteriovenous Malformation Within the Same Metamere

BACKGROUND

Spinal arteriovenous shunts are a common spinal vascular disorder. However, they can have a misleading clinical presentation and poor prognosis. They are classified into 4 types according to shunt points and drainage route, among which extradural arteriovenous fistula (eAVF) is the most rare, comprising only 1% of all spinal arteriovenous shunts. We report an extremely rare case of coexistent eAVF at the craniocervical junction and soft tissue arteriovenous malformation within the same metamere.

CASE DESCRIPTION

A 30-year-old man presented with neck pain. T2-weighted magnetic resonance imaging revealed a flow void at the right craniocervical junction compressing the spinal cord. Angiography revealed eAVF at the craniocervical junction. The patient was treated via transvenous embolization. After the procedure, shunt flow and symptoms markedly decreased. During the operation, an extracranial arteriovenous malformation under the occipital skin was detected immediately after occluding the shunt point.

CONCLUSIONS

This case indicates that transvenous embolization can be an effective treatment for eAVF and supports some hypotheses of arteriovenous malformation development. Additionally, it emphasizes the importance of examining a lesion with multiple modalities, including angiography, three-dimensional angiography, and cone-beam computed tomography, to understand the anatomy of the lesion.

Occipitocervical Fixation

BACKGROUND

Occipitocervical junction instability can lead to serious neurological injury or death. Open surgical fixation is often necessary to provide definitive stabilization. However, long-term results are limited to small case series.

OBJECTIVE

To review the causes of occipitocervical instability, discuss the indications for surgical intervention, and evaluate long-term surgical outcomes after occipitocervical fixation.

METHODS

The charts of all patients undergoing posterior surgical fixation of the occipitocervical junction by the senior author were retrospectively reviewed. A total of 120 consecutive patients were identified for analysis. Patient demographic characteristics, occipitocervical junction pathology, surgical indications, and clinical and radiographic outcomes are reported.

RESULTS

The study population consisted of 64 male and 56 female patients with a mean age of 39.9 years (range, 7 months to 88 years). Trauma was the most common cause of instability, occurring in 56 patients (47%). Ninety patients (75%) were treated with screw/rod constructs; wiring was used in 30 patients (25%). The median number of fixated segments was 5 (O-C4). Structural bone grafts were implanted in all patients (100%). Preoperative neurological deficits were present in 83 patients (69%); 91% of those patients improved with surgery. Mean follow-up was 35.1 ± 27.4 months (range, 0-123 months). Two patients died, and 10 were lost to follow-up before the end of the 6-month follow-up period. Fusion was confirmed in 107 patients (89.1%). The overall complication rate was 10%, including 3 patients with vertebral artery injuries and 2 patients who required revision surgery.

CONCLUSION

Occipitocervical fixation is a durable treatment option with acceptable morbidity for patients with occipitocervical instability.

Stereotactic radiosurgery as a feasible treatment for intramedullary spinal arteriovenous malformations: a single-center observation

Spinal cord intramedullary arteriovenous malformations are rare. For patients suffering from either hemorrhage or myelopathy, surgical or endovascular interventions are indicated. However, complete eradication of the nidus is often difficult because of its intramedullary location and complex angioarchitecture. In this report, we evaluate the feasibility and safety of stereotactic radiosurgery as a treatment modality for intramedullary spinal arteriovenous malformations (AVMs). Between 2010 and 2014, we performed stereotactic radiosurgery to treat four patients with intramedullary AVM and one with spinal arteriovenous metameric syndrome (one woman and four men; age range, 31-66 years). Three patients presented with myelopathy, and two suffered hemorrhages. Nidi were located in the cervical (three cases) and thoracic (two cases) spinal cord regions. Based on the angioarchitecture, surgery and endovascular embolization were indicated. When both modalities were deemed hazardous, radiosurgery using CyberKnife™ was offered. Radiation using marginal doses of 18 Gy was administered in three fractions. The mean follow-up period was 37.2 months (range, 16-62 months). After treatment, two of the three patients with myelopathy experienced either improvement or stabilization of their symptoms and one experienced worsening of dysesthesia. In two patients with hemorrhage, symptoms improved in one and remained stable in the other. No further hemorrhagic episodes were evident during follow-up. Follow-up angiograms showed marked shrinkage of the nidus located in the thoracic spinal cord in one case and angiographic stabilization in the others. As a treatment modality for intramedullary AVMs, CyberKnife™ is safe and can be considered when surgery or endovascular therapy is not indicated. To determine optimum radiation doses and protocols for treating spinal AVMs, further studies with more patients and long-term follow-up are required.

Surgical and Endovascular Treatment for Spinal Arteriovenous Malformations

Spinal arteriovenous malformation (AVM) is a broad term that constitutes diverse vascular pathologies. To date, various classification schemes for spinal AVM have been proposed in literature, which helped neurosurgeons understand the pathophysiology of the disease and determine an optimal treatment strategy. To discuss indications and results of surgical and endovascular interventions for spinal AVM, this article refers to the following classification proposed by Anson and Spetzler in 1992: type I, dural arteriovenous fistula (AVF); type II, glomus intramedullary AVM; type III, juvenile malformations; and type IV, perimedullary AVF. In general, complete obliteration of the fistula is a key for better outcome in type I dural and type IV perimedullary AVFs. On the other hand, in type II glomus and type III juvenile malformations, functional preservation, instead of pursuing angiographical cure, is the main goal of the treatment. In such cases, reduction of the shunt flow can alleviate clinical symptoms. Proper management of spinal AVM should start with neurological examination and understanding of angioarchitectures, which provide critical information that guides the indication and modality of intervention. Finally, close collaboration of the microsurgical and endovascular teams are mandatory for successful treatment.

Endovascular stent graft exclusion of a thoracic arteriovenous malformation in a patient with Cobb syndrome

Cobb syndrome is a rare neurocutaneous disorder characterized by spinal vascular abnormalities in association with a vascular lesion of the skin at the same metamere. Patients present after the onset of symptoms such as paraplegia, back pain, and, less commonly, fatigue due to heart failure. Available treatment options to date have included neurosurgical resection and endovascular embolization. We present a patient with Cobb syndrome with a progressively symptomatic arteriovenous malformation involving the thoracic vertebrae and left hemithorax, with extensive blood supply from the T3 to T10 intercostal arteries, and demonstrate successful endovascular thoracic stent graft placement and coil embolization.

Exclusively epidural spinal metameric arteriovenous shunts: case report and literature review

BACKGROUND CONTEXT

Spinal arteriovenous metameric syndrome (SAMS) is a subgroup of spinal arteriovenous malformations (AVMs). Most SAMS cases have intra- and extradural AVMs and suffer from hematomyelia, subarachnoid hemorrhage, or venous congestive myelopathy.

PURPOSE

To present a rare case of SAMS in which spinal AVMs were exclusively epidural. We reviewed previous literature and evaluated the feasibility of a treatment strategy using endovascular interventions, followed by surgical obliteration.

STUDY DESIGN

A case report and literature review of SAMS.

METHODS

We report a case of a 15-year-old boy suffering from SAMS in which epidural venous ectasia because of extradural AVMs caused spinal cord compression.

RESULTS

The patient was successfully treated with multiple sessions of transarterial embolization followed by open surgery. After the treatment, his neurologic deficits resolved. Postoperative angiography confirmed complete obliteration of extradural AVMs.

CONCLUSIONS

Although exclusively epidural spinal AVM is an uncommon type of SAMS, combined endovascular and surgical interventions can be an effective treatment for AVMs to achieve better radiologic outcomes and complete resolution of patient symptoms.

Spinal arteriovenous metameric syndrome in a neonate presenting with congestive heart failure: case report

BACKGROUND

Spinal arteriovenous metameric syndrome (SAMS) is a combination of more than two separate vascular malformations in the same embryonic metameres. This syndrome, also known as Cobb syndrome, is rare, especially in the neonate.

CASE DESCRIPTION

A neonatal girl with a birthmark in the occipital and posterior nuchal regions presented with severe heart failure on the day of birth. The large arteriovenous fistulas in the left hypoglossal canal and in the posterior nuchal region were embolized with detachable coils on the postnatal days 5 and 18, which improved heart failure markedly. The associated intramuscular arteriovenous malformation in the posterior neck was left untreated because large arteriovenous fistulas had been occluded. She grew up without any neurological deficits and developed with normal milestones until the latest follow-up of 8 years old.

CONCLUSION

To our knowledge, this is the first case with SAMS in a neonate presenting with congestive heart failure. Presence of a birthmark in a neonate presenting with congestive heart failure may suggest the possible underlying high-flow vascular malformations in the same metamere.

Endovascular treatment in spinal perimedullary arteriovenous fistula

This study includes 20 patients with 21 spinal perimedullary fistulae. There were nine Type IVa (42.8%) lesions, ten Type IVb (47.6%) and two Type IVc (9.5%) lesions. The dominant arterial supply was from the anterior spinal artery (47.6%), posterior spinal artery (19%) and directly from the radiculomedullary artery (28.5%). Sixteen lesions in 15 patients were treated by endovascular route using n-butyl-2-cyanoacrylate. Endovascular treatment was not feasible in five patients. Of the ten patients with microfistulae, catheterization failed/was not attempted in 40%, complete obliteration of the lesion was seen in 60% but clinical improvement was seen in 40% of patients. Catheterization was feasible in all ten patients with macrofistulae (nine type IVb and two type IVc lesions). Complete obliteration of the lesions was seen in 60% and residue in 30%. Clinical improvement was seen in 80% and clinical deterioration in 10%. In conclusion, endovascular glue embolization is safe and efficacious in type IVb and IVc spinal perimedullary fistulae and should be considered the first option of treatment. It is also feasible in many of the type IVa lesions.