Angiographic challenges of spinal dural and epidural arteriovenous fistulas: report on 45 cases.

PURPOSE: The localization of the fistula level in spinal dural arteriovenous fistulas (dAVFs) and epidural arteriovenous fistulas (edAVFs) remains a diagnostic challenge. METHODS: Consecutive patients with spinal dAVFs and edAVFs in the thoracic, lumbar, and sacral regions were included. The primary endpoint was to describe the characteristics of patients who required angiography with multiple catheterizations of segmental arteries (10 or more). RESULTS: Forty-five patients (median age 69 years; male 89%; dAVFs, n = 31; edAVFs, n = 14) were included. Spinal dAVFs commonly developed in the thoracic region and edAVFs in the lumbosacral region. Fistulas were predicted at the correct level or plus/minus 2 level in less invasive examinations using multi-detector CT angiography (n = 28/36, 78%) and/or contrast-enhanced MR angiography (n = 9/14, 64%). We encountered diagnostic challenges in the localization of fistulas in 6 patients. They underwent angiography a median of 2 times. In each patient, spinal levels were examined at a median of 25 levels with a median radiation exposure of 3971 mGy and 257 ml of contrast. Fistulas were finally localized at the high thoracic region (T4-6) in 3 patients, the sacral region (S1-2) in 2, and the lumbar region (L3) in 1. Four patients were diagnosed with edAVFs and 2 with dAVFs. The correlation coefficient between the fistula level and the rostral end of the intramedullary T2 high-signal intensity on MRI was interpreted as none. CONCLUSION: In patients in whom less invasive examinations failed for fistula localization, high thoracic or sacral AVFs need to be considered.

The negative impact of treatment delays on the long-term neurological outcomes of spinal dural arteriovenous fistulas: a longitudinal cohort study.

OBJECTIVE: Dural arteriovenous fistulas are rare vascular malformations that affect the brain and spinal cord. Spinal dural arteriovenous fistulas (sdAVFs) are the most frequently encountered vascular malformation affecting the spinal cord. The object of this study was to evaluate the impact of treatment delays on the long-term neurological outcomes of either open surgical or interventional treatment of sdAVFs. METHODS: In this retrospective, population-based cohort study, the authors examined consecutive patients with diagnosed sdAVFs at a tertiary care center between 2005 and 2020. Patients were assessed using the Aminoff-Logue disability scale (ALS) at various time points including symptom onset, primary care visit, first specialist outpatient visit, as well as both short and long-term follow-ups. The postoperative long-term ALS gait and bladder grades constituted the primary outcomes of the study. RESULTS: Among the 34 patients included in the study, the median age was 65 years, and there was a male predominance (71%). Most lesions were in the lumbar region (47%). Significant worsening in ALS gait and bladder grades was observed preoperatively, followed by postoperative improvements (p < 0.05). There was no difference in outcomes between surgical and endovascular treatments. Older age (OR 1.10, 95% CI 1.03-1.17, p = 0.007), worse preoperative ALS gait grades (OR 5.12, 95% CI 2.18-12.4, p < 0.001), and longer time from first specialist outpatient visit to first treatment (OR 1.00, 95% CI 1.00-1.01, p = 0.040) were independently associated with worse long-term gait outcomes. Only the preoperative ALS bladder score was a predictor of worse long-term bladder function (OR 92.7, 95% CI 28.0-306.7, p < 0.001). CONCLUSIONS: Both surgical and endovascular treatments for sdAVFs led to significant neurological improvements. However, treatment delays were associated with less favorable long-term outcomes. Prompt diagnosis and early intervention prior to symptom progression may enhance recovery and help to preserve neurological function.

Surgical evolution in spinal dural arteriovenous fistula treatment-a 7 years monocentric experience.

Accounting for 70% of all spinal vascular malformations, spinal dural arteriovenous fistulas (SDAVF) are the most common type of malformation. Interruption of the fistulous arterialized vein point is the goal of surgical treatment. The aim of the study was to compare open surgery (laminectomy) versus minimal invasive surgery (MIS) in SDAVF treatment. Between March 2013 and March 2020, we retrospectively collected 21 consecutive adult patients with SDAVF. Since March 2017, MIS has been routinely used for surgical treatment. Pre- and post-operative clinical evaluations used Aminoff-Logue score (ALS). Complication rate was noted. Post-operative occlusion of the malformation was confirmed by digital subtraction angiography (DSA) in all patients. MIS was compared to open surgery in terms of efficacy and complications with statistical evaluation. Standard laminectomy was performed in 12 patients and MIS technique in 9 patients. No difference was noted on pre-operative parameters. ALS and MRI signs of myelopathy were improved in all cases except for 1 patient in each group. All SDAVFs were excluded based on post-operative DSA. Significant differences were noted between the 2 groups in terms of perioperative blood loss (p<0.001), post-operative pain visual analog scale values (p<0.001), and first time out of bed (p<0.001). Wrong level surgery occurred in one patient in each group; patients were re-operated using the same technique. No infection or cerebrospinal fluid (CSF) leak was noted. In our experience, MIS is a safe alternative to open laminectomy for SDAVF treatment. MIS contributes to patient comfort and minimizes blood loss without increasing complication rate.

Endovascular embolisation as minimally-invasive treatment for spinal dural arteriovenous fistulas - evaluation of long-term results.

AIM OF STUDY: Spinal dural arteriovenous fistulas (sDAVF) are rare spinal cord lesions formed between a radicular artery and medullary vein leading to venous hypertension resulting in neurological impairment. Endovascular embolisation is a minimally-invasive method aiming to interrupt the shunt between the artery and vein. We report our experience with sDAVF treated endovascularly. MATERIAL AND METHODS: Clinical and procedural data of 16 consecutive patients diagnosed with sDAVF was reviewed. Pre- and post-operative neurological condition was evaluated using both the Aminoff and Logue disability scale and the VAS scale. Rates of complete occlusions, technical difficulties, and procedural complications were noted. RESULTS: Four of the patients were female and 12 were male; mean age was 62.4 years. Mean interval between symptom onset and treatment was 13.3 months. Complete occlusion was achieved in 88% (14/16 patients). Significant or moderate clinical improvement in long-term follow-up was observed in eight patients (50%). Recurrence was observed in two cases (13%). CONCLUSIONS AND CLINICAL IMPLICATIONS: While endovascular methods are being refined and thus achieving an increasing percentage of successful occlusions, patients should be closely monitored since this condition is recurrent and the clinical consequences of myelopathy can persist despite complete occlusion of the shunt.

Spinal Dural AVFs: Classifications and Advanced Imaging.

Spinal dural arteriovenous fistulas (SDAVFs) are the most common vascular shunts of the spine. They occur predominantly in men (more than 80%), commonly involve the thoracolumbar spine, and usually cause progressive myelopathy because of venous congestion of the spinal cord. Recent advanced imaging technology can visualize the detailed angioarchitecture of the spinal cord, and this provides more information of the regional microanatomy related with the shunt disease. We retrospectively analyzed the location of the shunt with adjacent vasculatures and assessed the efficacy and the sensitivity of each imaging modality. Based on these data, a new concept of classification for SDAVFs was reviewed.

Primary conus medullaris arteriovenous shunt and secondary lumbo-sacral epidural arteriovenous fistula: One malformation can hide another.

We report an anatomical-based association between conus medullaris pial arteriovenous shunt that drain caudally towards the lumbosacral area with very delayed onset of an acquired lumbar epidural shunt, draining secondarily towards intradural veins and responsible for a venous congestive myelopathy with identical clinical symptoms. These patients require close clinical and imaging follow-ups in order to propose adequate treatments before onset of irreversible neurological deficits. MRA should include the lumbo-sacral area in its field of view.

Outcomes following surgical versus endovascular treatment of spinal dural arteriovenous fistula: a systematic review and meta-analysis.

Although surgical resection is associated with a complete cure in most cases of spinal dural arteriovenous fistulas (SDAVF), there has been an increasing trend towards embolisation. We performed a systematic review and meta-analysis comparing surgical resection with endovascular treatment in terms of success of treatment, rate of recurrence and complications. A literature search was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Strength of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation Working Group system. Surgical outcomes such as initial treatment failure, late recurrence, neurological improvement and complications were compared between the two approaches. We included 57 studies with 2029 patients, of which 32 studies with 1341 patients directly compared surgery (n=590) and embolisation (n=751). Surgery was found to be associated with significantly lower odds of initial treatment failure (OR: 0.15, 95% CI 0.09 to 0.24, I2 0%, p<0.001) and late recurrence (OR 0.18, 95% CI 0.09 to 0.39, I2 0%, p<0.001). The odds of neurological improvement following surgery were also significantly higher compared with embolisation alone (OR: 2.73, CI:1.67 to 4.48, I2 :49.5%, p<0.001). No difference in complication rates was observed between the two approaches (OR 1.78, 95% CI 0.97 to 3.26, I2 0%, p=0.063). Onyx was associated with significantly higher odds of initial failure/late recurrence as compared with n-butyl 2-cyanoacrylate (OR: 3.87, CI: 1.73 to 8.68, I2 :0%, p<0.001). Surgery may be associated with superior outcomes for SDAVFs in comparison to endovascular occlusion. Newer embolisation agents like Onyx have not conferred a significant improvement in occlusion rate.

Dynamic contrast-enhanced magnetic resonance angiography for the localization of spinal dural arteriovenous fistulas at 3T.

OBJECTIVE: This study was undertaken to evaluate the accuracy of dynamic contrast-enhanced magnetic resonance angiography (DCE-MRA) in the precise location and demonstration of fistulous points in spinal dural arteriovenous fistulas (SDAVFs). METHODS: Fifteen patients (14 men, 1 woman; age range: 40-78 years; mean: 55.5 years) harboring SDAVF who underwent preoperative DCE-MRA and spinal digital subtraction angiography (DSA) between January 2012 and January 2015 were evaluated retrospectively. Two reviewers independently evaluated the level and side of the arteriovenous fistula and feeding artery on 3T DCE-MRA and DSA images. The accuracy of DCE-MRA was assessed by comparing its findings with those from DSA and surgery in each case. RESULTS: All 15 patients underwent DCE-MRA and DSA. DSA was unsuccessful in two patients due to technical difficulties. All cases were explored surgically, guided by the DCE-MRA. Surgery confirmed that 14 AVF sites were located in the thoracic spine, 5 in the lumbar spine, and 1 in the cervical spine. The origin of the fistulas and feeding arteries was accurately shown by DCE-MRA in 11 of the 15 patients. DCE-MRA also detected dilated perimedullary veins in all 15 patients. Overall, DCE-MRA facilitated DSA catheterization in 10 cases. In six patients, the artery of Adamkiewicz could be observed. In 15 out of 20 fistulas (75%), both readers agreed on the location on DCE-MRA images, and the κ coefficient of the interobserver agreement was 0.67 (95% confidence interval [CI], 0.16-0.87). In 13 of 16 shunts (75%), the DCE-MRA consensus findings and DSA findings coincided. The intermodality agreement was 0.77 (95% CI: 0.35-0.92). CONCLUSIONS: Our DCE-MRA studies benefited from the use of a high-field 3T MR imaging unit and reliably detected and localized the SDAVF and feeding arteries. As experience with this technique grows, it may be possible to replace DSA with DCE-MRA if surgery is the planned treatment.

Intracranial and Spinal Dural Arterio-Venous Fistula (DAVF): A Surgical Series of 107 Patients.

INTRODUCTION: Dural arteriovenous fistulas (DAVFs) is a challenging condition in vascular neurosurgery. Development of new endovascular techniques has progressively modified treatment strategies; however, surgery is still considered a valid option of treatment of this pathology. MATERIALS AND METHODS: From a retrospective analysis of our database, we selected 107 patients who underwent surgical treatment for DAVFs. Patients were grouped into five categories according to the Borden and Cognard classifications. Patients and treatment characteristics/outcome is reported. RESULTS: At admission, 30 (28 %) patients presented with intracranial hemorrhage. Fifteen (14 %) had seizure, whereas nearly half of the patients presented with non-aggressive symptoms, including headache (10, 9.3 %), cognitive impairment (8, 7.5 %), gait disturbance, and imbalance (8, 7.5 %). The majority of patients underwent surgical treatment of fistulas; in some cases, we elected combined surgical-endovascular (obliteration) treatment. CONCLUSIONS: Management of DAVF requires a multidisciplinary assessment and treatment strategies including surgical, endovascular, and radiosurgical treatment. The data reported confirmed that surgical treatment of DAVFs is associated with a good clinical and radiological (complete occlusion of the fistula) outcome in all cases, with a low rate of complications.

Preoperative Angiographic Protocol for the Surgical Management of Spinal Dural Arteriovenous Fistulas: A Technical Nuance for Safe Minimally Invasive Surgery.

BACKGROUND: Interruption of the fistulous point is the goal of treatment of spinal dural arteriovenous fistulas (dAVFs). Microsurgery remains a highly efficient treatment in terms of complete occlusion with the lowest risk of recurrence rate. It is reported that the hardest step involves finding the fistulous site itself, potentially extending surgical access and time and increasing potential postoperative surgical-related complications. The accurate preoperative detection of the shunt and spinal level together is crucial for guiding optimal, fast, and safe microsurgical treatment. METHODS: We describe a preoperative angiographic protocol for achieving a safe and simple resection of spinal dural arteriovenous fistulas based on a 6-year institutional experience of 42 patients who underwent minimally invasive procedures. Two illustrative cases are included to support the technical descriptions. RESULTS: The suspected artery associated with the vascular malformation of interest is studied in our angiographic protocol through nonsubtracted selective acquisitions in lateral projection. The resulting frames are reconstructed with three-dimensional rotational angiography. The implementation of the preoperative angiographic protocol allowed 100% of intraoperative identification of the fistulous point in all cases with the use of a minimally invasive approach. CONCLUSIONS: Nowadays, neurosurgeons advocate for minimally invasive procedures and procedures with low morbidity risk for treatment of spinal dural arteriovenous fistulas. Our preoperative approach for accurate angiographic localization of the fistulous point through nonsubtracted and three-dimensional reconstructed angiography allowed us to achieve safe and definitive occlusion of the shunt.

Surgical Management of a Spinal Dural Arteriovenous Fistula.

Spinal dural arteriovenous fistulas (SDAVFs) may have subtle clinical presentations and are often misdiagnosed. Clinical status gradually deteriorates following symptom onset making prompt identification and management essential. Here we present a case of a 67-year-old patient with rapidly progressing motor and sensory deficits to eventual right hemiplegia. Following imaging and surgical intervention, a thoracic SDAVF was identified and resected. This case report highlights a unique SDAVF with a stroke-like presentation. For patients with such presentation, without a clear source of intracranial pathology, spinal causes such as SDAVF could be considered.

Endovascular Embolization of a Lateral Sacral Fistula: 2-Dimensional Operative Video.

Spinal dural arteriovenous fistulas are the most common vascular malformations of the spine. They are localized in the sacral spine in 5% to 14% of the cases. They can be fed by the median or the lateral sacral arteries. These lesions present with nonspecific symptoms such as radiculopathy and/or myelopathy, which often leads to a delay in diagnosis. In this video, we present the case of a 65-yr-old gentleman with a lateral sacral dural arteriovenous fistula. The patient was referred to our institution after the outside facility workup was nondiagnostic. He presented with spastic paraparesis and bilateral radiculopathy. After patient informed consent was obtained, we performed a spinal diagnostic angiogram with catheterization and angiography of the internal iliac artery, which revealed the fistula. Onyx (Medtronic, Dublin, Ireland) embolization was performed, which led to a complete occlusion of the fistula. The patient had complete neurological recovery, and at 2-yr follow-up, imaging remained negative for a fistula. In this video, we discuss the nuances and key points related to the epidemiology, diagnosis, and treatment of lateral sacral fistulas.1-3.

Spinal dural arteriovenous fistula formation after scoliosis surgery: case report.

Spinal dural arteriovenous fistulas are diagnostically challenging lesions, and they are not well described in patients with a history of a spinal deformity correction. The authors present the challenging case of a 74-year-old woman who had previously undergone correction of a spinal deformity with subsequent revision. Several years after the last deformity operation, she developed a progressive myelopathy with urinary incontinence over a 6-month period. After evaluation at the authors' institution, an angiogram was obtained, demonstrating a fistula at the T12-L1 region. Surgical ligation of the fistula was performed with subsequent improvement of the neurological symptoms. This case is thought to represent the first fistula documented in an area of the spine that had previously been operated on, and to the authors' knowledge, it is the first case report to be associated with spinal deformity surgery. A brief historical overview and review of the pathophysiology of spinal dural arteriovenous fistulas is also included.

Intraoperative Neurophysiological Monitoring in Surgical Treatment of Spinal Dural Arteriovenous Fistulas: Technique and Results.

OBJECTIVE AND BACKGROUND: Data on intraoperative neurophysiological monitoring (IOM) during surgery of spinal dural arteriovenous fistulas (SDAVFs) are lacking. The purpose of this study was to evaluate the role of IOM during microsurgery for SDAVFs. MATERIALS AND METHODS: From March 2007 to March 2013, 12 patients had microsurgery with IOM for SDAVFs. The IOM included somatosensory-evoked potentials, motor-evoked potentials (MEPs), and - in selected cases - D-Waves. All patients were evaluated at admission and at follow-up (6, 12, and 24 months) with Aminoff-Logue Disability Scale for Gait-Aminoff-Logue Disability Scale (G-ALS) and Micturition-Aminoff-Logue Disability Scale (M-ALS). STATISTICAL ANALYSIS USED: Logistic regression was used for detecting the clinical risk factors influencing neurological functions after the treatment. RESULTS: During surgery, we registered the absence of significant modifications of evoked potentials in nine cases (75%), while improvement of MEPs occurred in three cases (25%). No false-negative case was registered, and IOM predicted the absence of new postoperative neurological deficit in all patients. At 24-month follow-up, nine patients improved their overall neurological status, while three patients remained stable. At univariate analysis, Aminoff-Logue Disability Scales for Gait and Micturition (G + M-ALS) score at 24-month follow-up was directly associated with the duration of symptom before the surgery (P = 0.024), preoperative G-ALS (P = 0.02), M-ALS (P = 0.022), and G + M-ALS scores (P = 0.045), and improvement of IOM after occlusion of the fistula (P = 0.025). CONCLUSIONS: In our series, no significant worsening of evoked potentials occurred and subsequently the surgical strategy was not changed by IOM. However, no false-negative case was registered, and IOM predicted the absence of new postoperative neurological deficit in all patients. Patients with improvement of IOM parameters after occlusion of the fistula had greater chances of postsurgical improvement at the univariate analysis.

Surgical management of spinal dural arteriovenous fistulas.

Spinal dural arteriovenous fistulas are the most common type of spinal arteriovenous malformations. Treatment options consist of microsurgical exclusion and/or endovascular embolization. We retrospectively identified all patients who benefited from surgical treatment at our tertiary center between January 2001 and December 2008. Clinical and imaging data were collected from patient files, including pre- and post-operative formal neurological examination, complete spine MRI and spinal digital subtraction angiography. Of our 30 patients, 25 were men and five were women with a median age of 62 years (range 24-76). The average delay between symptom onset and clinical diagnosis was 27 months (range 1-90). Complete cure of the fistula was obtained in all patients in a single surgical session with no procedural complications and no surgical morbidity. After a mean follow-up period of 32 months (range 14-128), 25 patients (83%) had improved, four were stable and one worsened. Despite recent advances in endovascular techniques and materials, there is a subgroup of patients for which surgery remains the best treatment option. Careful patient selection, a multidisciplinary approach and standardized surgical techniques can lead to excellent results with virtually no complications.

The Transdural Course of Radicular Spinal Cord Veins--A Microangiographical and Microscopical Study.

PURPOSE: This study focuses on the following questions: What are the morphological features at the transdural course of radiculomedullary veins? How are these short transdural segments that may harbour pathological arteriovenous shunts connected to the internal vertebral venous plexus? Is the conception of a reflux-impeding mechanism at the transdural segment indispensable and convincing? METHODS: A total of 102 radiculospinal veins were studied microscopically at various levels of the spinal canal using serial paraffin and semi-thin sections. In addition, 26 vessels were investigated microangiographically following orthograde (12) or attempted retrograde (14) opacification of the intradural venous segment with barium sulphate. After paraplast-embedding, contact-microradiographs were taken using high-resolution spectroscopic plates. RESULTS: At their transdural course, the veins showed narrowing of their lumen accompanied by changes in the vessel wall composition and a tortuous course. Two structurally distinct arrangements of the transdural segment could be identified: A slit type was seen in 60% of the veins studied and a bulge- or nodular type was seen in 35% of the veins. In total, 5% of cases could not be assigned to either one of these types. Reflux to radicular veins from the outside of the dura mater could be produced in 2 out of 14 specimens. The extradural venous plexus, which primarily receives the radicular vein, was composed more frequently of lacunar spaces rather than plexiform blood vessel convolutions. Rare observations were fibrotic, blind ending radiculomedullary veins and continuation of a distinct venous blood vessel after crossing the dura. CONCLUSIONS: Reflux from the epidural plexus to radicular veins is not reliably stopped at the dural level and possibly physiological. Different arrangements of the transdural course of the veins appear to be at least appropriate to modulate flow. The purpose for two different types of radicular vein exit is unclear. The clinical impact of disturbed reflux-control is uncertain, which is in stark contrast to the severe consequences resulting from dural arteriovenous shunts. The functional role of the probably predominant epidural venous plexus for the spinal cord blood circulation remains poorly understood.