Perimedullary Arteriovenous Fistula Research Articles

Pediatric peri-medullary arteriovenous fistula: Pearls for diagnosis and treatment

Pediatric type IVc perimedullary arteriovenous fistulae (PAVF) comprise a rare subcategory of spinal vascular malformations in which multiple spinal arteries directly connect with draining veins resulting in high-flow arteriovenous shunting and large intradural venous varicosities. Complete disconnection of the fistula is necessary to prevent hemorrhage or spinal compression. A surgical, rather than endovascular, approach proves favorable under specific circumstances. Due to the rarity of these pediatric fistulae, no large studies exist to enumerate these circumstances. This case report fills this void by detailing several considerations which favored surgery for a type IVc PAVF in a 17-year-old female patient.

Angioarchitecture Classification and Treatment Modalities of Craniocervical Junction Arteriovenous Fistulas: A Cohort Study of 155 Patients.

Craniocervical junction (CCJ) arteriovenous fistulas (AVFs) are rare. Variability in clinical manifestations and treatment strategies for CCJ AVFs stems from differences in their angioarchitecture. Our study aims to categorize CCJ AVFs based on their angioarchitecture and explore the associated clinical features and treatment modalities for distinct CCJ AVF types. The authors conducted a retrospective analysis of patients with CCJ AVFs treated at a single neurosurgical facility over the past decade. These patients were classified based on the angioarchitecture of their CCJ AVFs. The analysis included an evaluation of angioarchitecture, clinical characteristics, treatment strategies, and outcomes. The study included 155 patients, with a median age of 56 years, collectively manifesting 165 CCJ AVFs. Our classification identified 4 distinct CCJ AVF types: epidural AVFs (19 [11.5%]), dural AVFs (98 [59.4%]), radicular AVFs (33 [20.0%]), and perimedullary AVFs (15 [9.1%]). Further differentiation was applied based on the presence of pial feeders. The predominant fistula location was at cervical-1 (77.0%). Ascending intradural drainage (52.7%) and descending intradural drainage (52.1%) were frequently observed drainage patterns. Patients with dural AVF predominantly presented with venous hypertensive myelopathy, whereas patients with other types of CCJ AVFs showed a higher incidence of subarachnoid hemorrhage (P = .012). Microsurgery was the predominant treatment, applied in the management of 126 (76.4%) AVFs, whereas 8 (4.8%) AVFs exclusively underwent interventional embolization and 25 (15.2%) received a combination of interventional embolization and microsurgical treatment. CCJ AVFs can be distinguished based on the fistula location and the arterial feeders. Currently, microsurgery stands as the preferred treatment strategy for CCJ AVFs, whereas interventional embolization plays a distinctive role in cases with specific angioarchitecture or as a pretreatment measure before microsurgery.

Microsurgical intraluminal obliteration of type IV perimedullary arteriovenous fistula with an in situ hemostatic agent: illustrative case.

Spinal arteriovenous fistulas (SAVFs) are underdiagnosed entities that can lead to severe morbidity from spinal cord dysfunction or hemorrhage. Treatment options include endovascular embolization or direct surgical obliteration at the level of the arteriovenous shunt. The authors present a case of intraluminal microsurgical access for occlusion with a hemostatic agent of a type IV SAVF near the conus medullaris as an alternative to clip occlusion to avoid nerve root compromise. Temporary microsurgical clipping of the SAVF led to nerve root compromise detected via intraoperative monitoring. Instead, the authors advanced elongated pieces of a hemostatic agent directly into the arterial lumen via arteriotomy to create direct obliteration of the fistula without intraoperative monitoring changes. In patients unable to tolerate clipping of the SAVF because of nerve root involvement and neurophysiological signal decline, open access of the vessels and direct intraluminal obliteration using a hemostatic agent should be considered as an alternative method of fistula occlusion.

Spontaneous obliteration of a spinal perimedullary fistula.

We herewith report a young patient who had an incidental spinal vascular malformation of the cervicomedullary junction discovered during a work-up for anosmia. Angiography demonstrated a perimedullary spinal arteriovenous fistula with supply from lateral spinal arteries arising from bilateral V3 level segmental arteries. It was decided to manage the patient conservatively with magnetic resonance imaging monitored biannually. On a recent follow-up magnetic resonance, nearly 10 years later, we noted a subtle change in caliber and imaging characteristics at the posterior margin of the cervical medullary junction. Repeat digital-subtraction angiography showed no evidence of early venous filling from the previously involved branches. Microcatheter exploration of the right lateral spinal artery confirmed spontaneous occlusion of the spinal perimedullary arteriovenous fistula, without any persistent shunting. Spontaneous resolution of a spinal vascular malformation is rare; this case demonstrates the dynamic nature of shunting vascular malformations and that spontaneous obliteration of arteriovenous shunts is possible.

Treatment of high cervical arteriovenous fistulas in the craniocervical junction region.

The craniocervical junction (CCJ) is a complex region. Rarely, arteriovenous fistulas (AVFs) can occur in the CCJ region. Currently, it is accepted that CCJ AVFs should only refer to AVFs at the C1-C2 levels. It is reasonable to assume that high cervical CCJ AVFs are being referred to when discussing CCJ AVFs. High cervical CCJ AVFs can be divided into the following four types: dural AVF, radicular AVF, epidural AVF and perimedullary AVF. Until now, it was difficult to understand high cervical CCJ AVFs and provide a proper treatment for them. Therefore, an updated review of high cervical CCJ AVFs is necessary. In this review, the following issues are discussed: the definition of high cervical CCJ AVFs, vessel anatomy of the CCJ region, angioarchitecture of high cervical CCJ AVFs, treatment options, prognoses and complications. Based on the review and our experience, we found that the four types of high cervical CCJ AVFs share similar clinical and imaging characteristics. Patients may present with intracranial hemorrhage or congestive myelopathy. Treatment, including open surgery and endovascular treatment (EVT), can be used for symptomatic AVFs. Most high cervical CCJ AVFs can be effectively treated with open surgery. EVT remains challenging due to a high rate of incomplete obliteration and complications, and it can only be performed in superselective AVFs with simple angioarchitecture. Appropriate treatment can lead to a good prognosis.

Spinal Extramedullary Arteriovenous Fistulas: A 15-Year Endovascular Treatment Experience in a Tertiary Care Hospital in Thailand.

Spinal arteriovenous shunts are rare diseases. Different classifications have been proposed, but the most widely used are those classified by locations. Different locations (i.e., intramedullary and extramedullary) have different treatment outcomes and different posttreatment angiographical results. Our study presents the 15-year endovascular treatment outcomes of patients who had spinal extramedullary arteriovenous fistulas (AVFs) at Ramathibodi Hospital, which is a tertiary care hospital in Thailand. A retrospective medical record and imaging review of all patients with spinal extramedullary AVFs, which were confirmed by a diagnostic spinal angiogram in our institute from January 2006 to December 2020, were performed. The angiographic complete obliteration rate in the first session of endovascular treatment, clinical outcomes of the patients, and complications of the procedures for all eligible patients were analyzed. Sixty-eight eligible patients were included in the study. The most common diagnosis was spinal dural AVF (45.6%). The most common presenting symptoms were weakness, numbness, and bowel-bladder involvement (70.6%, 67.6%, and 57.4%, respectively). Ninety-four percent had spinal cord edema in preoperative magnetic resonance imaging. All patients had pial venous reflux. Sixty-four patients (94.1%) received endovascular treatment as the first option. The complete obliteration rate in the first session of endovascular treatment was 75% and was high in all subgroups except for the perimedullary AVF group. The overall intraoperative complication of endovascular treatment was 9.4%. Follow-up imaging showed no residual AVF in 50 patients (87.7%). Most of the patients (57.4%) had improvement of neurological functions at 3- to 6-month follow-up. Treatment results of spinal extramedullary AVFs were good in terms of angiographic aspects and clinical outcomes. This may have resulted from the locations of the AVFs, which mostly did not involve the spinal cord arterial supply, with the exception of perimedullary AVFs. Although perimedullary AVF is difficult to treat, it can be cured by careful catherization and embolization.

Angiographic Index for the Treatment Efficacy and Functional Outcomes of Spinal Cord Arteriovenous Shunts: the Vertebral Blush Sign.

The functional outcomes in spinal cord arteriovenous shunts (SCAVSs) are usually unpredictable from current assessments of treatment results. We aimed to investigate and propose anew index marker, the vertebral blush (VB) sign, for assessing the treatment efficacy of SCAVSs. This retrospective cohort study enrolled patients diagnosed with SCAVSs between June 2012 and May 2021. The VB sign was defined as the angiographic finding of reappearance or enhanced contrast staining of the vertebral bodies fed by shunt-related arteries observed after shunt occlusion. The primary outcome was the improvement in motor/sensory disturbances or sphincter impairments within 1 year after treatment. The secondary outcome was shunt recanalization. VB sign characteristics and associations with outcomes were analyzed. Of 65patients with SCAVSs, 57were eligible for VB sign assessment; among these, there were 26with the VB sign and 31without the VB sign. Among vascular shunts perimedullary arteriovenous fistula showed the greatest difference in prevalence rate between those with and without the VB sign (33.3%, n = 9/27 versus 10.0%, n = 3/30; P = 0.031). On multivariable logistic regression analysis, SCAVSs with the VB sign had significantly more favorable outcomes than those without the VB sign (adjusted odds ratio, 5.61; 95% confidence interval, 1.48-21.23; P = 0.01). There was no relationship between the VB sign and secondary outcomes (P = 0.35). The VB sign is independently associated with functional recovery after shunt occlusion and could be an assessment tool for the treatment efficacy of SCAVSs.

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

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. 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. 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. 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.

Differentiation between spinal dural arteriovenous fistulas, intramedullary spinal arteriovenous malformations, and perimedullary arteriovenous fistulas through magnetic resonance imaging

Differentiation between spinal dural arteriovenous fistulas, intramedullary spinal arteriovenous malformations, and perimedullary arteriovenous fistulas through magnetic resonance imaging

Arteriovenous Fistulas Fed by Spinal Arterial Feeders at the Craniocervical Junction Region.

Arteriovenous fistulas (AVFs) at the craniocervical junction (CCJ) region with spinal arterial feeders are rare. There are few reports on such diseases. This study retrospectively reviewed 20 consecutive cases with CCJ AVFs with spinal arterial feeders from our neurosurgical center, which can enrich the experience of diagnosis and treatment of such arteriovenous fistulas. To further explain the clinical manifestations, angiographic characteristics, and treatment strategies of CCJ AVFs with spinal arterial feeders and share the treatment experience of our neurosurgical center. A total of 113 patients with CCJ AVFs treated at our institution between January 2013 and December 2020 were enrolled. After analyzing their imaging data, 20 patients with CCJ AVFs with spinal arterial feeders were included. Clinical presentation, angiographic characteristics, intraoperative findings, and treatment outcomes were analyzed. The median age was 52 years (IQR 45-58 years). Twenty-four fistulas were included in this study and were classified based on angiographic characteristics: dural AVF (1 [4.2%] of 24), radicular AVF (15 [62.5%] of 24), epidural AVF (2 [8.3%] of 24), and perimedullary AVF (6 [25.0%] of 24). Subarachnoid hemorrhage occurred in 19 cases (95.0%) and was the main clinical manifestation. Thirteen patients (65.0%) were treated with microsurgery only, 6 (30.0%) with embolization and microsurgery, and 1 (5.0%) with interventional electrocoagulation. Nineteen patients (95.0%) had favorable outcomes. Subarachnoid hemorrhage was the most common presentation of CCJ AVFs with spinal arterial feeders. Different treatment strategies should be selected based on different angioarchitecture.

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

BackgroundAlthough 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...

Incidence and clinical characteristics of spinal arteriovenous shunts: hospital-based surveillance in Okayama, Japan.

There have been no accurate surveillance data regarding the incidence rate of spinal arteriovenous shunts (SAVSs). Here, the authors investigate the epidemiology and clinical characteristics of SAVSs. The authors conducted multicenter hospital-based surveillance as an inventory survey at 8 core hospitals in Okayama Prefecture between April 1, 2009, and March 31, 2019. Consecutive patients who lived in Okayama and were diagnosed with SAVSs on angiographic studies were enrolled. The clinical characteristics and the incidence rates of each form of SAVS and the differences between SAVSs at different spinal levels were analyzed. The authors identified a total of 45 patients with SAVSs, including 2 cases of spinal arteriovenous malformation, 5 cases of perimedullary arteriovenous fistula (AVF), 31 cases of spinal dural AVF (SDAVF), and 7 cases of spinal epidural AVF (SEAVF). The crude incidence rate was 0.234 per 100,000 person-years for all SAVSs including those at the craniocervical junction (CCJ) level. The incidence rate of SDAVF and SEAVF combined increased with advancing age in men only. In a comparative analysis between upper and lower spinal SDAVF/SEAVF, hemorrhage occurred in 7/14 cases (50%) at the CCJ/cervical level and in 0/24 cases (0%) at the thoracolumbar level (p = 0.0003). Venous congestion appeared in 1/14 cases (7%) at the CCJ/cervical level and in 23/24 cases (96%) at the thoracolumbar level (p < 0.0001). The authors reported detailed incidence rates of SAVSs in Japan. There were some differences in clinical characteristics of SAVSs in the upper spinal levels and those in the lower spinal levels.

411 Treatment Results of Arteriovenous Fistulas at the Craniocervical Junction: A Multicenter Cohort Study of 108 Patients

INTRODUCTION: No standard treatment has been established for the arteriovenous fistulas (AVFs) at the craniocervical junction (CCJ). METHODS: A total of 103 consecutive patients with the CCJ AVFs were collected from 29 centers that are members of Neurospinal society of Japan. Angiographic findings and the clinical characteristics of the CCJ AVFs were evaluated. RESULTS: Among 103 cases, dural AVF (59 cases), radicular AVF (12 cases), epidural AVF (16 cases), and perimedullary AVF (5 cases) were included. There were 11 cases in which combinations of the pathologies occurred in one case. 51 and 7 patients presented with subarachnoid hemorrhage (SAH) and intramedullary hemorrhage, respectively. 28 cases presented with congestive myelopathy, while there were 17 asymptomatic cases. Overall, 78 cases (76%) and 19 cases (18 %) underwent primary surgical or endovascular treatments, respectively. 4 cases (4%) underwent combined treatments. 14 cases (14%) required second treatments. The rate of initial treatment failure or recurrence was 2.6% after the surgical treatments (Surgery Group), while it was 63% of the endovascular treatment group (Endovascular Group). In multivariate analysis, endovascular treatment was the independent risk factor with significantly higher odds of initial treatment failure or recurrence (odds ratio [OR], 59; 95% confidence interval [CI], 11-324). Treatments related complications occurred in 28 cases (27 %). The rates of complications were 21% in the Surgery Group. While, it was 42% in the Endovascular Group. Complications included medulla/spinal/cerebellar infarction (12 cases), the cerebrospinal fluid leak (3 cases), and postoperative hematomas (3 cases).Post-operatively, an improvement of 1 or more in modified Rankin Scale (mRS), was observed in 60% and 37% of Surgery and Endovascular Groups, respectively with a median follow-up of 23.0 months. CONCLUSION: Based on the largest and latest multicenter cohort, this study showed that primary microsurgery was superior to endovascular treatment to achieve complete obliteration of the CCJ AVF in a single procedure.

Feasibility of Noninvasive Diagnosis of Spinal Vascular Diseases Using Time-Resolved Angiography With Stochastic Trajectories.

Background and Purpose: To determine the feasibility of time-resolved angiography with stochastic trajectories (TWIST) in the diagnosis of spinal dural arteriovenous fistula (SDAVF) and perimedullary arteriovenous fistula (PAVF).Methods: A total of 11 negative patients with TWIST examination were retrospective analyzed and then 18 patients with suspected spinal vascular diseases underwent TWIST. For negative patients, Adamkiewicz artery (AKA), great anterior radiculomedullary vein (GARV) and anterior spinal artery (ASA) were retrospective analyzed. In patients, the results of TWIST were compared with those of DSA.Results: The displaying rates of the ASA, AKA and GARV in 11 negative patients were 100, 90.9, and 90.9%, respectively. The AKA and GARV were separated on TWIST. Of 18 patients, 11 and three were diagnosed with SDAVF and PAVF, respectively. The spinal cord vascular malformation diagnosed on TWIST was consistent with DSA with an excellent intermodality agreement (Kappa = 0.92, p < 0.001). The feeding artery and side of all 11 SDAVF patients were displayed on TWIST and the results were consistent with DSA. For PAVF patients, the feeding artery in two patients and the sides as displayed on TWIST were consistent with DSA.Conclusions: TWIST enables the differentiation of the spinal artery and vein and the differential diagnosis of SDAVF and PAVF.

Embolization for Perimedullary Arteriovenous Fistulae: Pioneering Experience in Peru

Background Perimedullary arteriovenous fistulae, or type IV spinal cord arteriovenous malformations, are very rare and not well-known lesions. This paper aims to present our endovascular experience with these lesions. Methods We report our experience with 4 patients with perimedullary arteriovenous fistulae, subtypes b and c (macrofistulae), exhibiting severe neurological impairment. The patients were treated with endovascular embolization. Results Complete fistula eradication was achieved in all of them. One complication occurred. We discuss the natural history, pathophysiology, clinical presentation, prognosis and embolization techniques, along with the angiographic and clinical outcomes. Conclusion Our experience with endovascular embolization as an upfront treatment allowed us to eradicate these lesions in a safe and effective way, arresting the clinical worsening and reversing partially or completely the neurological injury in most of our cases.

Intraoperative Identification of the Shunt Point of Spinal Arteriovenous Malformations by a Selective Arterial Injection of Saline to Subtract Signals of Indocyanine Green: Technical Note

It is crucial to identify a shunt point for spinal arteriovenous malformation (AVM) treatment. For this purpose, some intraoperative supports have been reported-intravenous injection of indocyanine green (ICG), selective arterial injection of ICG, and selective arterial injection of saline with a high frame rate digital camera. However, there are difficulties in accurately identifying the shunt point, especially if the lesion has multiple feeders. The aim of this technical note was to report a novel method, selective arterial injection of saline to subtract signals of ICG, to precisely identify perimedullary arteriovenous fistula shunt points having multiple feeding arteries. After exposing the lesion, a 4-F catheter was cannulated into the origins of the segmental artery. ICG was injected intravenously as a first step, and then heparinized saline solution was flushed from the catheter. Compared with other methods, this method could identify the exact shunt point and was effective for certain shunt point obliterations. Despite having similar invasiveness, selective arterial injection of saline to subtract signals of ICG is superior to previously described techniques, such as selective arterial injection of ICG. Therefore, it will be useful in spinal arteriovenous malformation surgical treatment.

Surgical Treatment for Spinal Arteriovenous Malformation

In this paper, we outlined the diagnostic and treatment strategies for spinal arteriovenous malformations, focusing on dural and perimedullary arteriovenous fistula(AVF). In many patients with spinal arteriovenous malformations, the symptoms are non-specific. Therefore, we consider it is critical to detect the signal flow voids in the enlarged spinal veins using MRI. An accurate understanding of the vascular structures is indispensable for deciding appropriate treatment strategies. Hence, performing an angiography is essential. Regarding treatment, whether to select surgical or endovascular treatment for AVF depends largely on the institution's protocols. However, the treatment should always be based on an accurate diagnosis.

Cranio-vertebral junction arteriovenous fistula presenting with subarachnoid haemorrhage: A case report

Perimedullary arteriovenous fistulas are uncommon vascular malformations particularly if they involve the craniovertebral junction. The complexity of the angioarchitecture of these lesions poses a further diagnostic challenge. Moreover, the therapeutic management is controversial and can include observation alone, endovascular occlusion, or surgical exclusion, depending on both patient and the angiographic characteristics of the lesion.

Combined surgical and endovascular approach to treat a ventrally located perimedullary arteriovenous fistula

Perimedullary arteriovenous fistulae (PMAVFs) (also called type IV spinal cord arteriovenous malformations) are rare lesions. They are located in the subarachnoid space or just under the pia. The shunt occurs between the anterior spinal artery (ASA) and/or posterior spinal artery (PSA) and a network of perimedullary veins. The aim of the treatment, surgical or endovascular, is to occlude the fistula. This article presents a unique treatment strategy of a demanding strictly ventral PMAVF in the lower thoracic cord. A posterior surgical approach with spinal cord rotation followed by direct puncture of a distally located arterial feeder was achieved. Precise identification of the fistula with superselective contrast injections was obtained and accurate catheterization of the venous pouch with a microcatheter was performed. Complete occlusion of the PMAVF was achieved with coils.

Surgical Management for Craniocervical Junction Arteriovenous Fistula Targeting the Intradural Feeder

BackgroundCraniocervical junction arteriovenous fistula (CCJAVF) has a variety of forms, including dural and perimedullary arteriovenous fistulas. Owing to this anatomic variety, the terminologies for classifying CCJAVF, most of which aim to describe angiographic structures, have yet to be firmly established, and the current taxonomic classifications do not facilitate surgical strategies. Herein we focused on the existence of intradural feeder vessels, allowing the identification of 2 types of CCJAVF. This retrospective study aimed to assess the usefulness of our diagnostic classification for CCJAVF surgery. MethodsWe divided CCJAVF into 2 types: CCJAVF with an intradural feeder vessel and CCJAVF without an intradural feeder vessel. For the former type, we set the surgical goal of interrupting the intradural feeder and the draining veins behind the posterior spinal nerve. For the latter type, the surgical goal was to interrupt the draining veins behind the posterior spinal nerve. We retrospectively analyzed the outcomes of our surgical cases. ResultsOf 12 patients with CCJAVF, 8 underwent direct surgery. No patients showed exacerbation of neurological symptoms after surgery. One patient needed a second operation for residual shunt, and another patient developed an asymptomatic angiographic recurrence in the epidural space detected on follow-up imaging. The overall outcomes of surgical cases were good with an average modified Rankin Scale score of 1.0. ConclusionsOur results indicate that our diagnostic classification for CCJAVF has the potential to simplify CCJAVF treatment without compromising patient outcomes.