Spinal juvenile (Type III) extradural-intradural arteriovenous malformations

Recurrence Rates Following Treatment of Spinal Vascular Malformations: A Systematic Review and Meta-Analysis

BACKGROUND

Spinal vascular malformations (SVMs), including arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs), are a varied group of vascular lesions that can be subclassified according to localization, vascular structure, and hemodynamics. Early intervention is necessary to halt progression of disease and minimize irreversible dysfunction. We sought to characterize initial treatment success and recurrence rates following interventional treatment of various types of SVMs.

METHODS

A systematic review and meta-analysis were performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. SVMs were categorized into 4 groups: dural AVFs, perimedullary AVFs, intramedullary AVMs, and extradural-intradural AVMs (e.g., epidural, paraspinal). Initial occlusion, recurrence, and complication rates were compared using random-effects analysis.

RESULTS

There were 112 manuscripts included, with a total of 5626 patients with SVM. For treatment, 2735 patients underwent endovascular embolization, 2854 underwent surgical resection, and 37 underwent stereotactic radiosurgery. The initial treatment success and overall recurrence rates following surgical resection of all SVMs were 89.5% (95% CI: 80.5%-98.5%) and 2.3% (95% CI: 0.9%-3.7%), respectively. Those rates following endovascular embolization were 55.9% (95% CI: 30.3%-81.5%) and 27.7% (95% CI: 11.2%-44.2%), respectively. Higher rates of initial treatment success and lower rates of recurrence with surgery were observed in all subtypes compared to embolization. Overall complication rates were higher after embolization for each of the SVM categories.

CONCLUSIONS

Surgical resection of SVMs provided higher rates of initial complete occlusion and lower rates of recurrence than endovascular techniques. Attaining technical success through obliteration must still be weighed against clinical impact and natural history of the specific vascular malformation.

Spinal Vascular Shunts: A Patterned Approach

Spinal vascular shunts, including fistulas and malformations, are rare and complex vascular lesions for which multiple classification schemes have been proposed. The most widely adopted scheme consists of 4 types: type I, dural AVFs; type II, intramedullary glomus AVMs; type III, juvenile/metameric AVMs; and type IV, intradural perimedullary AVFs. MR imaging and angiography techniques permit detailed assessment of spinal arteriovenous shunts, though DSA is the criterion standard for delineating vascular anatomy and treatment planning. Diagnosis is almost exclusively based on imaging, and features often mimic more common pathologies. The radiologist's recognition of spinal vascular shunts may improve outcomes because patients may benefit from early intervention.

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.

Spinal Arteriovenous Malformation: Case Report and Review of the Literature

Spinal arteriovenous malformations (AVMs) are a rare form of spinal blood vessel defect that results in vessel engorgement leading to clinical signs secondary to mass effect and ischemia. We present the patient’s clinical course following suspicion of spinal AVM along with a review of current classification and imaging modalities.

Microsurgical or endovascular strategy for complete obliteration of spinal arteriovenous shunts in a single-institute 10-year retrospective study

The objective of this retrospective study is to more fully understand the optimal strategy to manage spinal arteriovenous (AV) shunts. This study included a cohort of 35 patients with a diagnosis of spinal AV shunts who were treated over the past 10 years at a single institute. Angiographic diagnosis of intramedullary AV malformations (IM-AVM), perimedullary AV fistulas (PM-AVF), dural AV fistulas (D-AVF), or epidural AV fistulas (ED-AVF) was carefully made, and the microsurgical or endovascular strategy for them was determined at the interdisciplinary meeting consisting of neurospinal surgeons and endovascular specialists. Endovascular surgery was first considered whenever safely possible. Microscopic direct surgery using intraoperative image guidance was considered for cases in which endovascular access was challenging or not safely possible. Combined treatment was another option. The clinical condition was assessed using the modified Rankin scale (mRS). Seventeen of 35 cases were treated with microscopic direct surgery, 13 cases with endovascular surgery, and the remaining five cases with the combination. Complete angiographic obliteration was achieved in 30 of 35 cases (85.7%). Although residual AV shunts was recognized in 3 cases of IM-AVM, 1 case of PM-AVF and 1 case of ED-AVF, no angiographic recurrence was present with an average postoperative follow-up period of 44 months. The average mRS before surgery was 2.37 and significantly improved to 1.94 at the most recent follow-up. Interdisciplinary collaboration between neurospinal surgeons and endovascular specialists should be standard to achieve safe and successful outcomes in treating such rare and difficult spinal disorders.

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.

Microsurgical treatment and outcomes of spinal arteriovenous lesions: Learned from consecutive series of 105 lesions

Spinal arteriovenous lesions (SAVLs), arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs), are rare and can devastatingly impair spinal cord function. This study aimed to evaluate clinical outcomes after microsurgical treatment with the aid of intraoperative indocyanine green video-angiography (ICG-VA) in a large series of patients with SAVLs. We retrospectively reviewed the cases of 95 consecutive patients with 105 SAVLs (77 spinal AVFs, 28 spinal AVMs) who had been treated surgically during 2010-2016 in two hospitals by the same experienced surgeon. All patients had undergone magnetic resonance imaging and digital subtraction angiography preoperatively and were assessed using the modified Aminoff and Logue Scale (mALS). All lesions were resected or occluded using ICG-VA. No ICG-VA-related complications occurred. Compared with AVF, patients with AVM tended to be younger (p<0.001) and were at higher risk of an associated aneurysm (p=0.021), hemorrhage (p<0.001), pain (p<0.001) and abrupt onset (p<0.001). SAVLs were most common in the lower thoracic region (45.71%), and their most common clinical presentation was paresthesia (89.52%). At a mean follow-up of 33.3months, mALS indicated significant improvement in patients with spinal AVFs (p<0.001) and AVMs (p=0.002) compared with their status preoperatively. An improved, stable clinical status was noted at the last follow-up in 93.51% of those with AVFs and 89.28% of those with AVMs. Thus, microsurgical treatment of SAVLs produced a lasting positive clinical outcome in a large cohort of consecutive patients. ICG-VA proved to be an efficient intraoperative tool during resection of these lesions, especially in patients with an AVF.

Epidemiology, clinical presentation, diagnostic evaluation, and prognosis of spinal arteriovenous malformations

Spinal arteriovenous malformations (sAVM) are rare vascular pathologies whose natural history remains incompletely understood. Advances in diagnostic imaging, coupled with the evolution of endovascular and microsurgical techniques have led to the description of a number of classification schemes for these lesions. An updated method has changed AVM classification from five categories of lesion based on source and location of feeder vessels to three categories based on pathophysiology. These categories include extradural arteriovenous fistulae (AVFs), intradural AVFs, extradural-intradural AVFs, intramedullary AVMs, and conus medullaris AVM each with individual subclassifications. Treatment outcomes have been shown to differ based on classification criteria. The increased use of advanced imaging prior to surgical intervention has facilitated the treatment of AVFs. Definitive diagnosis and characterization have traditionally required digital subtraction angiography, which is now being supplemented with other forms of noninvasive imaging such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA). Epidemiologically, intradural dorsal AVFs account for 80% of all sAVMs, and are characterized by low-pressure shunts located in the sleeve of the dorsal nerve root. Microsurgical treatment has been shown to be highly effective in cases of intradural dorsal AVFs, although many cases are also amenable to durable occlusion using liquid embolics. Conus medullaris AVMs, which has only been recently characterized as a separate category of sAVM, is best treated using a combination of embolization and microsurgery. Successful treatment of sAVM mandates a thorough understanding of the anatomy and classification of these lesions. The purpose of this chapter is to review and summarize the classification, natural history, and prognosis of sAVMs.

Classification and pathophysiology of spinal vascular malformations

Spinal arteriovenous malformations and fistulas comprise spinal vascular malformations (sVMs), a rare but challenging neurosurgic entity. A number of mechanisms have been proposed as explanations of neurologic decline in the setting of arteriovenous shunting, including venous hypertension, venous congestion, hemorrhage, vascular steal, or mass effect, which can be worsened with venous varices or aneurysmal dilations. Anatomic location and features dictate the categorization of sVMs. Two major systems are in place for classification of sVMs - (1) the American/French/English connection and (2) the Spetzler system - as well as a number of systems that have been described over the past century.

Vascular Diseases of the Spinal Cord: Infarction, Hemorrhage, and Venous Congestive Myelopathy

Vascular pathologies of the spinal cord are rare and often overlooked. This article presents clinical and imaging approaches to the diagnosis and management of spinal vascular conditions most commonly encountered in clinical practice. Ischemia, infarction, hemorrhage, aneurysms, and vascular malformations of the spine and spinal cord are discussed. Pathophysiologic mechanisms, clinical classification schemes, clinical presentations, imaging findings, and treatment modalities are considered. Recent advances in genetic and syndromic vascular pathologies of the spinal cord are also discussed. Clinically relevant spinal vascular anatomy is reviewed in detail.