Spinal arteriovenous malformations: new classification and surgical treatment

Case report: Surgical treatment and long-term successful outcome of a spinal intramedullary vascular malformation in a dog

A 3.5-year-old male intact Staffordshire terrier crossbreed dog was presented with a one-week history of progressive paraparesis with fecal and urinary incontinence. Neurological examination was consistent with a T3-L3 myelopathy. A magnetic resonance imaging study revealed the presence of a well-circumscribed hemorrhagic space-occupying lesion at the level of T12, suspected to be a vascular malformation, such as cavernoma or arteriovenous fistula, primary hematoma or hamartoma; less likely considerations included hemorrhagic inflammation or hemorrhagic primary or secondary neoplasia. A dorsal laminectomy, durotomy, and midline dorsal myelotomy were performed with a surgical microscope, and the vascular lesion was identified and removed. Histological examination of surgical samples yielded fibrin, hemorrhage, hematoidin pigment, and some neural tissue. Although a lining wall was visualized during surgery consistent with a vascular malformation, there was no histological confirmation of such a structure, hampering definitive classification of the lesion. There was no gross or histopathological evidence that would support a diagnosis of a hamartoma or benign neoplasia. The dog was paraplegic with intact nociception the day following surgery. Ambulation was recovered within 2 weeks. Progressive and complete recovery of neurological function was seen over the next 12 weeks. No recurrence of neurological dysfunction was seen over a 12-month follow-up period. Surgical treatment should be considered in dogs with spinal intramedullary vascular lesions which can have a successful long-term outcome.

Conus medullary arteriovenous malformation mimicking intramedullary tumor: a case report

Background

Vascular malformation of the spine accounted for 3–4% of all intradural lesions. Spinal arteriovenous malformation (AVM) is often missed because of overlapping symptoms with other pathology and ambiguous imaging. Here, we report a conus medullary AVM that mimics intramedullary tumours either from clinical findings or MR imaging.

Case presentation

We report a 24-year-old man with left foot monoparesis, paresthesia, and intermittent claudication for the last 3 months. Magnetic resonance imaging revealed a strongly enhanced intramedullary lesion with a hypointense signal on T1-weighted images and a hyperintense signal on T2-weighted images without flow void, suggesting an intramedullary tumour of ependymoma. Left-sided hemilaminectomy was performed, revealing an AVM on conus medullary. Microsurgical resection was performed by subsequently ligating the arterial feeder and draining vein using a temporary clip. Improvement of neurological status without postoperative sequelae was noted.

Conclusions

Because of the similarity in epidemiology, symptoms, clinical progression, and imaging, suspicion of spinal AVM should remain. This case highlights that appropriate and meticulous surgical resection can preserve the patient's neurological function.

Spinal Vascular Shunts: Single-Center Series and Review of the Literature of Their Classification

Spinal arteriovenous shunts (sAVSs) are an uncommon disease, constituting 3 to 4% of intradural lesions; 70% of these lesions are spinal arteriovenous fistulas (sAVFs), whereas spinal arteriovenous malformations (sAVMs) are rarer. Both share the problem of their classification due to the heterogeneity of their angioarchitecture. The aim of this study is to report a series of sAVSs treated in the neurosurgery department of the Hospital Nacional Guillermo Almenara during the 2018–2020 period and to present an overview of the current literature on sAVS classification. We reviewed all medical records of patients diagnosed with sAVFs and sAVMs during the 2018–2020 period, and then we analyzed images with Horos v4.0.0, illustrated some cases with Clip Studio Paint v1.10.5, and performed a descriptive statistical analysis with SPSS v25. Twelve patients were included in this study, eight of which were women (67%) and four of which were men (33%); the age range was from 3 to 74 years. Eight sAVSs were sAVFs, whereas four were sAVMs. The most frequent clinical manifestation was chronic myelopathy in seven patients (58%). Of those treated only by embolization, seven (70%) resulted in complete occlusion (five sAVFs and two sAVMs), while three (30%) remained with a residual lesion. At last follow-up, five patients (42%) improved clinically, and the seven remaining (58%) maintained the same neurological state. sAVSs require a detailed study of their angioarchitecture for proper management. The endovascular treatment is safe with acceptable cure rates. The surgical option should not be set aside.

Role of the Cervical Anterior Spinal Artery in the Endovascular Treatment of Vascular Diseases: Bystander, Accomplice, Victim, or Friend?

The cervical anterior spinal artery (ASA) is a very important artery arising from the intracranial vertebral artery (VA). It can play different roles in endovascular treatment (EVT) of spinal vascular diseases. The current understanding of these roles is incomplete; therefore, we performed this review. We found that cervical ASA can be involved in many spinal vascular diseases, such as arteriovenous fistula (AVF), arteriovenous malformation (AVM), and aneurysm, and can serve as a collateral channel in proximal VA occlusion. In AVF and AVM, when the cervical ASA is involved, it often plays the role of an accomplice or victim because it acts as the feeder or as a bystander that does not provide blood flow to the AVF and AVM. In cervical ASA aneurysm, the ASA is a victim. During EVT of VA aneurysms or stenoses, the cervical ASA ostia can be covered or occluded, resulting in ASA ischemia. In this situation, the ASA is a victim. In VA occlusion or the subclavian steal phenomenon, the cervical ASA can serve as a collateral channel to provide blood flow to the posterior circulation. In this case, the ASA plays the role of a friend. According to the role of the cervical ASA in spinal vascular diseases, EVT should be determined “case by case.” Most importantly, when EVT is performed to treat these diseases, the cervical ASA axis must be preserved. Therefore, understanding the role of the cervical ASA in spinal vascular diseases is crucial.

Intracranial Subarachnoid Haemorrhage Caused by Cervical Spinal Dural Arteriovenous Fistulas: Case Report

Cervical spinal vascular abnormalities commonly present with progressive myelopathy as a result of venous congestion. They are not very prone to bleed and tend to be underdiagnosed due to their subtle clinical presentation. We came across a rare case of intracranial subarachnoid haemorrhage caused by cervical spinal dural fistula in the Imperial College Healthcare NHS Trust Hospitals/UK in June 2020. We diagnosed the patient under strict evidence base medicine guidance, which otherwise would have been missed. We discussed the case in several multidisciplinary team (MDT) meetings, and patient was treated under the joint care of the neurology and neurosurgical teams. Patient made a full recovery and discharged home with no neurological defects or complications. Here, we reported this case with all the evidence we gathered from our MDT discussion. We hope our experience would help improve the diagnosis and management protocol for future patients with a similar condition.

Vascular Spinal Cord Disorders

Vascular disorders of the spinal cord are uncommon yet under-recognized causes of myelopathy. Etiologies can be predominantly categorized into clinical and radiographic presentations of arterial ischemia, venous congestion/ischemia, hematomyelia, and extraparenchymal hemorrhage. While vascular myelopathies often produce significant morbidity, recent advances in the understanding and recognition of these disorders should continue to expedite diagnosis and proper management, and ideally improve patient outcomes. This article comprehensively reviews relevant spinal cord vascular anatomy, clinical features, radiographic findings, treatment, and prognosis of vascular disorders of the spinal cord.

Spinal cord arterio-venous shunts: From classification to therapeutic management

Spinal Cord Arterio-Venous shunts (SCAVSs) are a rare disease. The aim of this paper is to describe how we classify and consider management of SCAVSs in relation to the location of the shunt focusing mainly on intradural SCAVSs. The anatomical features of the SCAVSs together with data provided by MRI and CT scans allow identification of four types of SCAVSs: paraspinal, epidural, dural and intradural ones. Clinical and neuroradiologic characteristics are described for each entity as well as the therapeutic endovascular management at our institution between 2002 and 2020. The therapeutic management of SCAVSs, and in particular of intradural shunts, remains mainly based on endovascular treatment as a first-choice approach. Understanding properly the lesional and regional vascular anatomy is mandatory to plan an appropriate therapeutic strategy and obtain good clinical results stable at long term follow up.

Revisiting the Vertebral Venous Plexus-A Comprehensive Review of the Literature

The venous drainage of the vertebral and paravertebral regions is important for a better understanding of hematogenous disease spread. Moreover, the spine surgeon must be well acquainted with this anatomy to minimize intraoperative and postoperative complications. A comprehensive review of the vertebral venous plexus (Batson plexus) was performed with a concentration on the clinical and surgical correlations of this venous network.

Spinal dural arteriovenous fistula: A rare cause of progressive myelopathy and bladder and bowel dysfunction

Spinal dural arteriovenous fistula (SDAVF) is a rarely seen vascular lesion in the spinal cord and is often overlooked. If left untreated in the early stages, it is associated with severe morbidity and may lead to progressive myelopathy and bladder and bowel dysfunction. A 55-year-old male patient was admitted with complaints of lower extremity weakness, gait disorder, urinary retention, and stool retention. Based on physical examination and magnetic resonance imaging findings, a preliminary diagnosis of SDAVF was made. The diagnosis was confirmed by spinal angiography showing SDAVF on the left T6. Microsurgery was planned, once endovascular embolization failed. Although symptoms of progressive myelopathy and bladder and bowel dysfunction are rarely seen, SDAVF diagnosis should not be overlooked, and it should be kept in mind that early diagnosis and treatment prevent severe morbidities.

Compression of the S1 Nerve Root by an Extradural Vascular Malformation: A Case Report and Discussion of Atypical Causes of Lumbar Radiculopathy

We present a case of lumbar radiculopathy due to a vascular malformation in the lumbar spine and discuss various causes of atypical lumbar radiculopathy. Lumbar radiculopathy is a condition of neurologic deficits and painful symptoms of the lower extremities due to nerve root compression, most commonly at the L5 and S1 levels. Several factors contribute to lumbar radiculopathy, including intervertebral disc herniation, foraminal stenosis, and spinal instability. There are also a number of atypical causes, including medication side effects or metabolic disorders, which produce symptoms of radiculopathy but do not involve compression of the nerve root. Anatomic variations in the nerve roots or vascular supply surrounding the nerve root may also increase the risk of developing radiculopathy and serve as an obstacle to interpreting imaging during a preoperative workup. A 38-year-old woman presented with sudden onset radicular symptoms in her right lower extremity. Lumbar magnetic resonance imaging demonstrated a right-sided L5-S1 extruded nucleus pulposus. Her symptoms failed to improve after conservative management so she underwent surgical decompression of L4-S1. Intraoperatively, we discovered an extensive, extradural vascular malformation present at the L5-S1 level and believed this to be the true cause of her radiculopathy. This case represents an atypical cause of lumbar radiculopathy and demonstrates the importance of considering atypical causes during diagnostic workup and preoperative planning.

Advances in 3D angiography for spinal vascular malformations

Spinal vascular malformations are difficult to diagnose lesions that can be associated with significant permanent morbidity. The angioarchitecture of spinal vascular anatomy and the associated pathologies have only recently been illuminated by the advent of spinal angiography. However, conventional spinal digital subtraction angiography is often limited by significant variability, overlapping vessels, as well as an inability to understand the precise location of the nidus or fistula in relation to the spinal cord and spine. In this study, we present 4 unique cases wherein 3-dimensional rotational angiography (3DRA) with dual volume acquisition was useful in defining the anatomy of spinal fistulas as well as planning treatment.

Diagnostic accuracy and efficiency of combined acquisition of low-dose time-resolved and single-phase high-resolution contrast-enhanced magnetic resonance angiography in a single session for pre-angiographic evaluation of spinal vascular disease

Background/Purpose

The purpose of this study was to evaluate the utility and efficacy of combined low-dose, time-resolved (TR) and single-phase high-resolution (HR) contrast-enhanced MRA (CE-MRA) as a pre-angiographic study for spinal vascular disease.

Materials and methods

Seventeen consecutive patients with suspected spinal vascular disease were retrospectively reviewed. All patients underwent combined low-dose TR CE-MRA and three-dimensional single-phase HR CE-MRA at 3 Tesla, followed by conventional spinal digital subtraction angiography (DSA) within 90 days. Six patients underwent additional spinal MRA and DSA for treatment follow-up. Spinal lesions were analyzed in terms of presence, disease type, laterality, spinal level, and number of arterial feeders.

Results

Low-dose TR CE-MRA helped proper localization of subsequent HR CE-MRA in two patients with high or low level of the lesion. For initial detection of spinal vascular disease, sensitivity, specificity and accuracy of CE-MRA were 93.3% (n = 14/15), 100% (n = 3/3), and 94.4% (n = 17/18), respectively. In characterization of dural arteriovenous fistula (AVF), perimedullary AVF, spinal cord arteriovenous malformation (AVM), and extraspinal AVM, CE-MRA correctly characterized in 86.7% (n = 13/15) among the positive findings, and in 88.9% (n = 16/18) among the several patients including negative results. CE-MRA showed matched per-case localization of arterial feeders within 1 vertebral level in 80% (n = 12/15), and matched per-lesion localization in 78.3% (n = 18/23).

Conclusion

Combined low-dose TR CE-MRA and single-phase HR CE-MRA at 3 Tesla was an effective and accurate non-invasive tool for the pre-angiographic evaluation of spinal vascular diseases in a single session.

Hospital complications and costs of spinal arteriovenous malformations in the United States from 2002-2014

BACKGROUND

Spinal arteriovenous malformations (AVMs) are rare disease entities with significant morbidity if untreated. Risk factors of complications, hospitalization and costs-of-care remain in need of characterization.

METHODS

Using the National Inpatient Sample years 2002-2014, adult subjects with spinal AVMs who underwent either laminectomy with lesion excision or endovascular embolization were extracted using ICD-9-CM diagnostic code 747.82. Predictors of inpatient complications, hospital length of stay (HLOS), and discharge home were evaluated using multivariable regression. Cost was evaluated using inflation-adjusted healthcare cost [charge*(cost/charge ratio)]. Mean differences (B), odds ratios (OR) and 95% CIs are reported. Significance was assessed at P<0.001.

RESULTS

In 2546 weighted admissions, age was 54.4±16.5-years (laminectomy: 70.0%, embolization: 30.0%). Fifteen percent suffered inpatient complications. Cost of hospitalization was $ 41216±38511 and was elevated for subjects with complications ($67571±2636, vs. no complications: $36562±723, P<0.001). Increased costs for categories of complications ranged from $ 16525 (renal/urinary) to $62246 (thromboembolism). In surgical subjects, complications were more costly ($ 69761±2896, vs. no complications: 36520±809, P<0.001). On multivariable analysis, major/extreme disease severity and major/extreme mortality risk were associated with increased complications and HLOS (P<0.001). Elective admissions had shorter HLOS (B=-4.3-days, [-4.8, -3.8], P<0.001) and higher odds of discharge home (OR=2.6 [2.1-3.2], P<0.001). Laminectomy (vs. embolization) was associated with complications (OR=2.6, 95% CI [1.7-3.8], P<0.001), HLOS (B=3.4-days [2.9-4.0], P<0.001), and decreased discharge home (OR=0.3 [0.2-0.4], P<0.001).

CONCLUSIONS

In spinal AVMs, high disease severity, non-elective admissions, and surgery are associated with complications, HLOS, and discharge to a non-home facility. Costs are elevated in patients suffering complications. Future studies are warranted.

Location, length, and enhancement: systematic approach to differentiating intramedullary spinal cord lesions

Purpose

Intramedullary spinal cord abnormalities are often challenging to diagnose. Spinal cord biopsy is a high-risk procedure with the potential to cause permanent neurological injury. Magnetic resonance imaging is the modality of choice for diagnosis and preoperative assessment of patients with spinal cord abnormalities. The radiologist’s ability to narrow the differential diagnosis of spinal cord abnormalities has the potential to save patients from invasive approaches for diagnosis and also guide appropriate management.

Approach/methods

This article will provide a systematic approach to the evaluation of intramedullary spinal cord lesions—with emphasis on location, length and segment distribution, and enhancement pattern—to help narrow the differential diagnosis. In doing so, we will review various spinal cord pathologies, including demyelinating and metabolic conditions, neoplasms, and vascular lesions.

Summary/conclusion

Although intramedullary spinal cord abnormalities can be a challenge for the radiologist, a systematic approach to the differential diagnosis with a focus on lesion location, cord length and segment involvement, as well as enhancement pattern, can greatly help narrow the differential diagnosis, if not synch the diagnosis. This strategy will potentially obviate the need for an invasive approach to diagnosis and help guide treatment.

Teaching points

• Imaging diagnosis of intramedullary spinal cord lesions could obviate cord biopsy.

• Evaluation of cord lesions should focus on location, length, and enhancement pattern.

• In demyelination, the degree of cross-sectional involvement is a distinguishing feature.

Study and therapeutic progress on spinal cord perimedullary arteriovenous fistulas

Spinal cord perimedullary arteriovenous fistulas (PMAVFs) are rare and belong to type IV spinal cord arteriovenous malformations (AVMs). Little is known regarding the treatment and prognosis of spinal cord PMAVFs. In the present study the relevant literature from PubMed was reviewed, and it was found that these fistulas can occur at all ages but are more common in children. In children, most spinal cord PMAVFs are large and with high flow, begin with bleeding and are frequently associated with hereditary hemorrhagic telangiectasia. However, in adults, most spinal cord PMAVFs are small and with low flow and begin with progressive spinal cord dysfunction. The early diagnosis of spinal cord PMAVFs is generally difficult, and symptoms can be very severe at the time of diagnosis. Digital subtraction angiography remains the gold standard; however, computed tomography angiography and magnetic resonance angiography are also promising. Spinal cord PMAVFs can be treated by endovascular embolization, surgical removal or a combination of the two methods. Most spinal cord PMAVFs show good outcomes after the appropriate treatment, and the prognosis is primarily associated with the blood flow of the PMAVF. For high-flow spinal cord PMAVFs, endovascular embolization is more effective and can lead to a good outcome; however, for low-flow spinal cord PMAVFs, surgical removal or the combination with endovascular embolization is the optimal choice. The prognosis for low-flow types is slightly worse than for high-flow spinal cord PMAVFs in children, but the outcome is acceptable.

Spinal arteriovenous malformations: Is surgery indicated?

Purpose:

To identify clinico-radiological distinguishing features in various types of spinal arteriovenous malformations (AVM) with an aim to define the role of surgical intervention.

Materials and Methods:

Hero's modified Di Chiro classification differentiated four types of spinal AVMs on digital subtraction angiogram (DSA) in 74 patients: I. Dural arteriovenous fistulae (n = 35, 47.3%); II. Glomus/intramedullary (n = 13, 17.6%); III. Juvenile/metameric (n = 4, 5.4%); and, IV. Ventral perimedullary fistula (n = 21, 28.4%). A patient with extradural AVM remained unclassified. Demographic profiles, DSA features and reason for surgical referral were recorded. Statistical comparison of discrete variables like gender, spinal cord level, presentation and outcome was made using Chi-square test; and, continuous variables like age, feeder number, duration of symptoms and number of staged embolizations by one way analysis of variance with Boneferoni post hoc comparison. Embolization alone (n = 39, 52.7%), surgery alone (n = 16, 21.6%), and combined approach (n = 4, 5.4%) were the treatments offered (15 were treated elsewhere).

Results:

Type I-AVM occurred in significantly older population than other types (P = 0.01). Mean duration of symptoms was 13.18 ± 12.8 months. Thoracic cord involvement predominated in type-I and III AVMs (P = 0.01). Number of feeding arteries were 1 in 59.7%; 2 in 29.0%; and, multiple in 11.3% patients, respectively. Staged embolization procedures in type-III AVM were significant (P < 0.01). Surgical referral was required due to: Vessel tortuosity/insufficient parent vessel caliber (n = 7); residual AVM (n = 4); low flow AVM (n = 3); and, multiple feeders (n = 2). Check DSA (n = 34) revealed complete AVM obliteration in 26 and minor residual lesion in eight patients. Neurological status improved in 26 and stabilized in 25 patients.

Conclusions:

Differentiating between Type I-IV AVMs has a significant bearing on their management. Surgical intervention should be considered as an important adjunct/alternative to therapeutic embolization.

The Preventive Effect of Endovascular Treatment for Recurrent Hemorrhage in Patients with Spinal Cord Arteriovenous Malformations

BACKGROUND AND PURPOSE

Spinal cord AVMs represent rare and insufficiently studied pathologic entities. Embolization is thought to play an important role in the management of spinal cord AVMs. Factors for recurrent hemorrhage and the impact of endovascular treatment on prevention of recurrent hemorrhage remain to be confirmed. We aimed to assess recurrent hemorrhagic incidence of spinal cord AVMs and its prevention by endovascular treatment.

MATERIALS AND METHODS

We reviewed 80 patients with spinal cord AVMs by spinal cord angiography who had hemorrhage before the first endovascular treatment at New York University Medical Center, Beth Israel Medical Center, or Roosevelt Hospital in New York. We compared the baseline and radiologic characteristics of patients with and without recurrent hemorrhage by the log-rank test and the Cox proportional hazards model.

RESULTS

We observed recurrent hemorrhage in 35 (44%) patients (1/41 patients with endovascular treatment and 34/39 patients without endovascular treatment). The median length of total follow-up was 659 days (interquartile range, 129-2640 days), and the median length from first-to-recurrent hemorrhage was 369 days (interquartile range, 30-1596 days). The log-rank test revealed that endovascular treatment and venous thrombosis reduced recurrent hemorrhage, and associated aneurysm was related to recurrent hemorrhage. Even in multivariate analysis, the endovascular treatment reduced (hazard ratio, 0.027; P < .0001) and associated aneurysm increased (hazard ratio, 3.4; P = .044) the risk of recurrent hemorrhage.

CONCLUSIONS

Endovascular embolization is the first choice of treatment for spinal cord AVMs and is effective in preventing recurrent hemorrhage.

Imaging diagnosis and the role of endovascular embolization treatment for vascular intraspinal tumors

Intraspinal tumors comprise a large spectrum of neoplasms, including hemangioblastomas, paragangliomas, and meningiomas. These tumors have several common characteristic imaging features, such as highly vascular mass appearance in angiography, hypointense rim and serpentine flow voids in MRI, and intense enhancement after intravenous contrast administration. Due to their rich vascularity, these tumors represent a special challenge for surgical treatment. More recently, the surgical treatment of intraspinal vascular tumors has benefited from the combination of endovascular techniques used to better delineate these lesions and to promote preoperative reduction of volume and tissue blood flow. Endovascular embolization has been proven to be a safe procedure that facilitates the resection of these tumors; hence, it has been proposed as part of the standard of care in their management.

Intraoperative direct puncture and embolization (IOPE) using a glue material for spinal cord arteriovenous fistula: a case report

INTRODUCTION

Spinal arteriovenous fistula (AVF) is treated by embolization or surgery. However, transarterial embolization or surgery is difficult in rare cases when the fistula site is very complicated to access especially as in fistular nidus supplied by posterior and anterior spinal artery. We present the case which was treated with intraoperative direct puncture and embolization (IOPE) using glue material, since the usual transarterial or transvenous neurointerventional approach was difficult to embolize the AVF.

METHODS

A 36-year-old woman presented with progressive leg weakness and pain after a 20-year history of lower back pain. She had pelvic and spinal AVF combined with arteriovenous malformation (AVM). Despite prior treatment of the pelvic lesion with radiotherapy and coil embolization, the spinal lesion persisted and caused repeated subarachnoid hemorrhages. A spinal angiogram revealed a tortuous and long feeder of the AVF which had growing venous sac, as well as AVM. Two embolization trials failed because of the long tortuosity and associated anterior spinal artery. Four months later, drastic leg weakness and pain occurred, and IOPE was performed using a glue material.

RESULTS

The subsequent recovery of the patient was rapid. One month later, the use of a strong opioid could be discontinued, and the patient could walk with aid. A follow-up spinal angiogram revealed that the venous sac of the AVF had disappeared.

CONCLUSION

In spinal AVF which is not feasible to access by usual intervention approach and to dissect surgically, IOPE with glue material can be considered for the treatment.

MRI and MRA of spinal cord arteriovenous shunts

The purpose of this review is to describe the diagnostic criteria for spinal cord arteriovenous shunts (SCAVSs) when using magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), and to discuss the extent to which the different MRI and MRA sequences and technical parameters provide the information that is required to diagnose these lesions properly. SCAVSs are divided into four groups according to location (paraspinal, epidural, dural, or intradural) and type (fistula or nidus); each type of lesion is described. SCAVSs are responsible for neurological symptoms due to spinal cord or nerve root involvement. MRI is usually the first examination performed when a spinal cord lesion is suspected. Recognition of the image characteristics of vascular lesions is mandatory if useful sequences are to be performed-especially MRA sequences. Because the treatment of SCAVSs relies mainly on endovascular therapies, MRI and MRA help with the planning of the angiographic procedure. We explain the choice of MRA sequences and parameters, the advantages and pitfalls to be aware of in order to obtain the best visualization, and the analysis of each lesion.

Venous drainage of the spine and spinal cord: a comprehensive review of its history, embryology, anatomy, physiology, and pathology

Venous drainage of the spine and spinal cord is accomplished through a complex network of venous structures compartmentalized to intrinsic, extrinsic, and extradural systems. As the literature on this topic is scarce, the following review was performed to summarize the available literature into a single coherent format. The medical literature on the spinal venous system was reviewed using online sources as well as historical documents that were not available online in regard to history, embryology, anatomy, and physiology with a particular emphasis on the pathology affecting this system. The spinal venous system is complex and variable. Proper understanding of all aspects is critical for the management of the pathology that results from its failure.

Spinal glomus (type II) arteriovenous malformations: a pooled analysis of hemorrhage risk and results of intervention

BACKGROUND

The natural history and treatment results for spinal glomus (type II) arteriovenous malformations (AVMs) remain relatively obscure.

OBJECTIVE

To calculate spinal glomus (type II) AVM hemorrhages rates and amalgamate results of intervention.

METHODS

We performed a pooled analysis via the PubMed database through May 2012, including studies with at least 3 cases. Data on individual patients were extracted and analyzed using a Cox proportional hazards regression model to obtain hazard ratios for hemorrhage risk factors.

RESULTS

The annual hemorrhage rate before treatment was 4% (95% confidence interval [confidence interval]: 3%-6%), increasing to 10% (95% CI: 7%-16%) for AVMs with previous hemorrhage. The hazard ratio for hemorrhage after hemorrhagic presentation was 2.25 (95% CI: 0.71-7.07), increasing to 13.0 within the first 10 years (95% CI: 1.44-118). The overall rates of complete obliteration were 78% (95% CI: 72%-83%) for surgery and 33% (95% CI: 24%-43%) for endovascular treatment. Long-term clinical worsening occurred in 12% of patients after surgical treatment (95% CI: 8%-16%) and in 13% after endovascular treatment (95% CI: 7%-21%). No hemorrhages occurred after complete obliteration. After partial surgical treatment, the annual hemorrhage rate was 3% (95% CI: 1%-6%); no hemorrhages were reported over 196 patient-years after partial endovascular treatment.

CONCLUSION

Spinal glomus (type II) AVMs with previous hemorrhage, particularly within 10 years, demonstrated a greater risk of hemorrhage. Complete obliteration and even partial endovascular treatment significantly decreased their hemorrhage rate.

Multimodal endovascular treatment of a vertebrovertebral fistula presenting with subarachnoid hemorrhage and hydrocephalus

Vertebrovertebral fistulae are rare vascular malformations that uncommonly can rupture to present clinically as intracranial subarachnoid hemorrhage. We report a 69-year-old man presenting following spontaneous apoplectic collapse. Initial workup revealed diffuse, intracranial subarachnoid hemorrhage, intraventricular hemorrhage and hydrocephalus. However, the etiology was not apparent on CT angiography of the head. Catheter-based angiography was performed, demonstrating a single-hole, high-flow vertebrovertebral fistula, arising from the V2 segment and decompressing into both cervical and skull base venous structures. Definitive treatment consisted of endovascular fistula obliteration with a combination of coil and liquid embolic material. The patient made a full neurological recovery. High cervical and skull base fistulae are rare causes of intracranial hemorrhage; endovascular treatment is effective at disconnection of the arteriovenous shunt.

A new classification scheme for spinal vascular abnormalities based on angiographic features

BACKGROUND AND PURPOSE

To determine the interobserver reliability of a newly proposed classification scheme for angiographic classification of spinal vascular malformations including arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs).

METHOD

A study was performed done in which 1-2 representative angiographic images of 26 spinal AVFs and/or AVMs were independently classified by five fellows in the ACGME accredited Endovascular Surgical Neuroradiology (ESN) program and two external interventionalists in the absence of any other clinical or imaging data. From these observations the interobserver reliability for each category and the overall scheme were determined in terms of the median weighted kappa statistic.

RESULTS

The overall interobserver reliability for the new classification scheme was a Kappa of 0.53 (Z = 21.3, P = <.0001) among the seven raters. The Kappa for individual grades was as follows: grade I (k = 0.66), grade II (k = 0.50), grade III (k = 0.44), and grade IV (k = 0.58). Three or more raters agreed on 100% of the cases. The interobserver reliability was high among the two practicing interventionalist raters (k = 0.55, 95% confidence interval 0.3-0.8). The interobserver reliability remained high among junior ESN fellows (k = 0.65).

CONCLUSION

The new classification scheme provided satisfactory reliability even in the hands of less experienced observers. The scheme can be used with minimal training and other concurrent data and can be relied upon to provide consistent results.

Rotational angiography for diagnosis and surgical planning in the management of spinal vascular lesions

Object

The management of spinal vascular malformations has undergone significant evolution with the advent of advanced endovascular and angiographic technology. Three-dimensional rotational spinal angiography is an advanced tool that allows the surgeon to gain a better appreciation of the anatomy of these spinal vascular lesions and their relation to surrounding structures. This article describes the use of rotational angiography and 3D reconstructions in the diagnosis and management of spinal vascular malformations.

Methods

The authors present representative cases involving surgical treatment planning for spinal vascular malformations with focus on the utility and technique of rotational spinal angiography. They report the use of rotational spinal angiography for a heterogeneous collection of vascular pathological conditions.

Results

Eight patients underwent rotational spinal angiography in addition to digital subtraction angiography (DSA) for the diagnosis and characterization of various spinal vascular lesions. Postprocessed images were used to characterize the lesion in relation to surrounding bone and to enhance the surgeon's ability to precisely localize and obliterate the abnormality. The reconstructions provided superior anatomical detail compared with traditional DSA. No associated complications from the rotational angiography were noted, and there was no statistically significant difference in the amount of radiation exposure to patients undergoing rotational angiography relative to traditional angiography.

Conclusions

The use of rotational spinal angiography provides a rapid and powerful diagnostic tool, superior to conventional DSA in the diagnosis and preoperative planning of a variety of spinal vascular pathology. A more detailed understanding of the anatomy of such lesions provided by this technique may improve the safety of the surgical approach.

Microsurgical management of glomus spinal arteriovenous malformations: pial resection technique: Clinical article

OBJECT

Intramedullary, or glomus, spinal arteriovenous malformations (AVMs) are rare vascular lesions amenable to resection with or without adjuvant embolization. The authors retrospectively reviewed the senior author's (R.F.S.'s) surgical series of intramedullary spinal AVMs to evaluate clinical and radiographic outcomes.

METHODS

Detailed chart and radiographic reviews were performed for all patients with intramedullary spinal AVMs who underwent surgical treatment between 1994 and 2011. Presenting and follow-up neurological examination results were obtained and graded using the modified Rankin Scale (mRS) and McCormick Scale. Surgical technique, outcomes, complications, and long-term angiographic studies were reviewed.

RESULTS

During the study period, 20 patients (10 males and 10 females) underwent resection of glomus spinal AVMs. The mean age at presentation was 30 ± 17 years (range 7-62 years). The location of the AVMs was as follows: cervical spine (n = 10), thoracic spine (n = 9), and cervicothoracic junction (n = 1). The most common presenting signs and symptoms included paresis or paralysis (65%), paresthesias (40%), and myelopathy (40%). Perioperative embolization was performed in the majority (60%) of patients. Pial AVM resection was performed in 17 cases (85%). Angiographically verified AVM obliteration was achieved in 15 patients (75%). At a mean follow-up duration of 45.4 ± 52.4 months (range 2-176 months), 14 patients (70%) remained functionally independent (mRS and McCormick Scale scores ≤ 2). One perioperative complication occurred, yielding a surgical morbidity rate of 5%. Three symptomatic spinal cord tetherings occurred at a mean of 5.7 years after AVM resection. No neurological decline was observed after endovascular and surgical interventions. No deaths occurred. Long-term angiographic follow-up data were available for 9 patients (40%) at a mean of 67.6 ± 60.3 months (range 5-176 months) following AVM resection. Durable AVM obliteration was documented in 5 (83%) of 6 patients.

CONCLUSIONS

Intramedullary AVMs may be safely resected with satisfactory clinical and angiographic results. The pial resection technique, which provides subtotal AVM nidus resection, effectively devascularized these lesions, as confirmed on postoperative angiography, without violating the spinal cord parenchyma, thereby potentially reducing iatrogenic injury.

Endovascular embolization for symptomatic perimedullary AVF and intramedullary AVM: a series and a literature review

INTRODUCTION

Perimedullary arteriovenous fistula (AVF) has shunt on the spinal cord surface and it can be treated with surgery, or endovascular embolization. Intramedullary arteriovenous malformation (AVM) has its nidus in the cord and is difficult to treat either by surgery or endovascular technique. We report our experience with endovascular embolization in the treatment of perimedullary AVF and intramedullary AVM.

METHODS

Four consecutive cases of spinal perimedullary AVF and six intramedullary AVM were retrospectively reviewed. These cases were evaluated and treated at Beijing Tiantan Hospital, China, over a 2-year period. A review of previously reported cases was also performed.

RESULTS

There was no significant difference in the presentations (P = 0.348), level of lesions (P = 0.350), arterial suppliers (P = 0.801), and associated vascular anomalies between perimedullary AVF and intramedullary AVM, except for age (P = 0.014) and treatment modalities (P = 0.003). The patients with perimedullary AVFs were younger in our cases; the age at onset of symptoms averaged 25.8 years compared to 31.7 years for intramedullary AVMs. There was a significant male predominance for both lesions, and a significantly higher incidence of subarachnoid hemorrhage than in spinal dural AVFs. Regarding treatment, endovascular coil embolization is frequently used in perimedullary AVF and liquid embolic agent is an effective therapeutic choice in intramedullary AVM.

CONCLUSION

Perimedullary AVF and intramedullary AVM are dissimilar with dural AVF in clinical characteristics. Our experience suggests that the endovascular treatment of spine perimedullary AVFs and intramedullary AVMs is feasible and effective. Endovascular treatment for intramedullary AVMs is still challenging, the main problem is acute ischemia injury of the spinal cord.

Endovascular treatment of spinal arteriovenous lesions: beyond the dural fistula

During the past few decades, there have been significant advances in the understanding of spinal vascular lesions, mainly because of the evolution of imaging technology and selective spinal angiography techniques. In this article, we discuss the classification, pathophysiology, and clinical manifestations of spinal vascular lesions other than DAVFs and provide a review of the endovascular approach to treat these lesions.

Differential diagnosis of T2 hyperintense spinal cord lesions: part B

Hyperintense spinal cord signal on T2-weighted images is seen in a wide-ranging variety of spinal cord processes. Causes including simple MR artefacts, trauma, primary and secondary tumours, radiation myelitis and diastematomyelia were discussed in Part A. The topics discussed in Part B of this two part series include multiple sclerosis, subacute combined degeneration of the spinal cord, cord infarction, arteriovenous shunts, transverse myelitis, neurosarcoidosis, AIDS-associated vacuolar myelopathy, and syringohydromyelia. Characterization of the abnormal areas of T2 signal as well as their appearance on other MR imaging sequences, when combined with clinical context and laboratory investigations, will often allow a unique diagnosis, or at least aid in narrowing the differential diagnosis. A wide range of instructive cases is discussed here, with review of the published reports focusing on pertinent MR features to aid in diagnosis.

Spinal glomus-type arteriovenous malformations: microsurgical treatment in 20 cases

Object

Glomus-type spinal arteriovenous malformations (AVMs) are rare. In the literature only small series and anecdotal reports can be found, and there are no prospective series elucidating the natural course or the superiority of 1 treatment regimen over another (such as surgery versus embolization versus conservative treatment). Microsurgical treatment of spinal AVMs often seems difficult because many lesions are not anatomically suitable for primary microsurgical occlusion and are therefore treated with first-line neuroradiological interventions or not at all.

Methods

Between 1989 and 2005, 20 patients with glomus-type AVMs underwent microsurgical treatment at 2 major neurosurgical centers in Germany. The history of symptoms in these patients ranged from 2 days to 11 years. Four patients presented with subarachnoid hemorrhage, 2 with intramedullary hematoma, 4 with paresthesia or pain, and 10 with clinical signs of myelopathy. Seven patients underwent partial embolization prior to microsurgery. The authors only operated on AVMs accessible from a dorsal or dorsolateral approach. Neurological status was assessed with the McCormick classification scheme. Follow-up data were obtained from outpatient records. Three patients were interviewed over the telephone and 4 patients were not available for follow-up evaluation.

Results

Surgery was performed via a laminectomy in 14 and hemilaminectomy in 6 patients. The microsurgical technique used consisted of retrograde dissection of the AVM from the venous side in most cases. Four (20%) of 20 patients showed worsening of neurological symptoms to a worse McCormick grade, probably caused by suspected venous stasis directly after surgery, however only 1 patient (5%) suffered permanent deterioration after surgery. In 14 patients postoperative angiography proved complete occlusion in 11 patients, including the presence of a remnant requiring a second operation with complete occlusion thereafter in 1 patient. In 3 patients occlusion was incomplete: a small residual AVM remained in 1 patient, and a discrete feeding vessel without a vein was evident in 2 patients.

Conclusions

Spinal cord AVMs are rare. If embolization is not possible, surgery may be indicated in selected cases. Spinal AVMs behave differently after incomplete occlusion either surgically or with embolization. A postoperative reduction in symptoms is frequent despite the presence of small remnants, and the risk of neurological deficits seems relatively low even in residual AVMs. Therefore, treatment need not necessarily aim at complete occlusion if that would be associated with an unacceptably high risk of neurological deficits.

National trends in spinal arteriovenous malformations

OBJECT

Spinal arteriovenous malformations (AVMs) are rare and understudied vascular lesions that cause neurological insult by mass effect, venous obstruction, and vascular steal. These lesions are challenging entities to treat because of their complicated anatomy and physiology. Current management options include open microsurgery, endovascular embolization, and stereotactic radiosurgery.

METHODS

Our study used the National Inpatient Sample database to analyze outcome data for spinal AVMs treated nationwide over an 11-year period from 1995 through 2006. Trends in procedural management, hospital course, and epidemiology of spinal AVMs are investigated.

RESULTS

Annually, an average of 300 patients presented with spinal AVMs requiring hospital treatment. The average length of hospital stay for this treatment has declined from more than 9 days in 1995 to 6 days in 2006. However, the average cost of a hospital stay has increased from < $30,000 to nearly $70,000. Whereas one-half of spinal AVMs were treated operatively in 1995, one-third were managed operatively in 2006.

CONCLUSIONS

Spinal AVMs are being increasingly treated by endovascular, radiosurgical, or combined means. A discussion of modern strategies to treat these disorders is presented.

Endovascular management of spinal vascular malformations: history and literature review

Spinal vascular malformations represent a complex group of entities whose treatment paradigm continually evolves. Given the ever-increasing role of endovascular therapy, it is the goal of the authors to review the current literature regarding this therapeutic tool and to provide recommendations guiding management. A thorough literature search was conducted using Medline, with subsequent articles being identified through cross-referencing. The analysis revealed that, since its introduction in the 1960s, endovascular therapy has been used to manage the entire spectrum of spinal vascular malformations, during which period it has undergone considerable technological and technical evolution. As such, embolization has proved of growing therapeutic utility, largely resulting from the mounting evidence supporting its safety and efficacy, in addition to the inherent minimally invasive nature. This alternative to surgical intervention will be increasingly used as first-line therapy in spinal vascular malformations.

Onyx embolization of a thoracolumbar perimedullary spinal arteriovenous fistula in an infant presenting with subarachnoid and intraventricular hemorrhage

Identifying a source of spontaneous subarachnoid hemorrhage (SAH) or intraventricular hemorrhage (IVH) in patients with negative results on cranial angiographic imaging can be a diagnostic challenge. The authors present the case of a 14-month-old girl who presented with lethargy and spontaneous SAH and IVH, and later became acutely paraplegic. Except for the SAH and IVH, findings on neuroimages of the brain were normal. Magnetic resonance imaging revealed an intramedullary thoracolumbar spinal cord hemorrhage that was found to be associated with arterialized veins intraoperatively. Catheter-based diagnostic angiography identified a spinal perimedullary macroarteriovenous fistula (macro-AVF) that was completely embolized with Onyx, negating the need for further surgical intervention. The authors believe this to be the first reported case of a thoracolumbar perimedullary macro-AVF presenting with SAH and IVH. In addition, descriptions of Onyx embolization of a spinal AVF in the literature are rare, especially in pediatric patients.

Intramedullary lesions of the conus medullaris: differential diagnosis and surgical management

The medullary conus represents a distinct entity of the spinal cord regarding its anatomical, clinical and microsurgical features. An overview of the pathologic processes of this region is provided. Epidemiological, clinical and neuroradiological characteristics of neoplastic (glial tumors, non-glial tumors, metastasis, primary melanomas) and non-neoplastic lesions (granulomatous lesions, abscess, parasitic infections, vascular, demyelinating and dysembryogenetic lesions) are discussed. Main MR imaging characteristics used to differentiate neoplastic from non-neoplastic lesions consist in pathological spinal cord expansion, gadolinium-enhancement and tumoural cyst formation. Management strategies differ substantially, depending on the kind of lesion. According to the suspected pathological entity radical resection, biopsy or conservative treatments are reasonable options. Intraoperative electrophysiological monitoring is a fundamental part of the surgical setting.

Neck and low back pain: neuroimaging

Spine imaging accounts for a major share of expenses related to neck and back pain. Improving image quality translates into better morphologic evaluation of the spine. Unfortunately, the morphologic abnormalities on spine imaging are common and nonspecific, obscuring the relevance to patient symptomatology. Furthermore, distinction between degenerative and age-related changes is not clear. The key is clinical correlation of imaging findings. This article presents a concise and illustrated discussion of spinal neuroimaging related to neck and back pain, with emphasis on degenerative disease.