Surgical treatment of high grade dural arteriovenous fistulae

Navigation guided small craniectomy and direct cannulation of pure isolated sigmoid sinus for treatment of dural arteriovenous fistula

Dural arteriovenous fistula (DAVF) is a rare condition affecting approximately 1.5% of 1,000,000 individuals annually. It frequently occurs in the transsigmoid and cavernous sinuses. An isolated sigmoid sinus is extremely rare and is treated by performing transfemoral transvenous embolization along the opposite transverse sinus. A 69-year-old woman presented with asymptomatic Borden type III/Cognard type III DAVF involving an isolated sigmoid sinus. She underwent a staged operation in which a navigation system was used to expose the sigmoid sinus in the operating room before transferring the patient to the angio suite for transvenous embolization. Various modalities have been used to treat DAVF, including surgical disconnection, transarterial embolization, transvenous embolization, and stereotactic radiosurgery. However, treating DAVF cases where the affected sinus is isolated can be challenging because an easily accessible surgical route may not be available. In this case, direct sinus cannulation and transvenous embolization were the most effective treatments.

Endovascular treatment for sphenoidal region dural arteriovenous fistula

Sphenoidal region dural arteriovenous fistulas (DAVFs) are rare. Endovascular treatment (EVT) is an effective treatment approach. However, understanding and performing EVT for sphenoidal region DAVFs are difficult and challenging. Therefore, we performed a review to explore this issue further. In this review, we discuss the dural feeders and venous structures of the sphenoidal region, the angioarchitecture of sphenoidal region DAVFs, the role and principle of EVT, various EVT techniques, and the prognosis and complications associated with EVT. We found that various EVT techniques, including transarterial embolization (TAE), retrograde transvenous embolization (TVE), and direct puncture EVT, can be used to treat sphenoidal region DAVFs. TAE represents the most commonly utilized approach. TVE and direct puncture EVT should be limited to highly selective cases. EVT must penetrate the fistula and very proximal venous recipient pouch with a liquid embolic agent or coil the fistula point to have a complete curative effect. Successful EVT can lead to the obliteration of sphenoidal region DAVFs and a good clinical outcome. However, these complications cannot be neglected.

Sphenoparietal Sinus Dural Arteriovenous Fistulas: A Series of 10 Patients

BACKGROUND

Dural arteriovenous fistulas (DAVFs) of the sphenoparietal sinus or sphenoid wing region are uncommon lesions with unique and interesting angioarchitecture. Understanding appropriate anatomy and recognizing patterns provide important treatment implications.

OBJECTIVE

To describe a single surgeon's experience with open surgical treatment of sphenoparietal sinus DAVFs, the surgical indications for this uncommon lesion, and the microsurgical techniques related to its treatment and to review the literature on its surgical treatment.

METHODS

Consecutive cases of sphenoparietal sinus DAVF treatment conducted by a single surgeon over 24 years (1997-2020) were retrospectively reviewed. Published reports of similar cases were reviewed.

RESULTS

Of 202 surgically treated DAVFs, 10 lesions in 10 patients were sphenoparietal sinus DAVFs. Four patients presented with intracranial hemorrhage, 3 with headache, and 2 with pulsatile tinnitus; 1 patient was incidentally identified as having a DAVF during treatment for a ruptured aneurysm. Most patients (7 of 10) had undergone endovascular embolization previously. Nine patients had Borden type III DAVFs and one had a Borden type II fistula. Surgery in all 10 patients resulted in angiographically confirmed fistula obliteration. Clinical outcomes at the last follow-up, measured by a modified Rankin Scale (mRS) score, were excellent in 6 patients (mRS ≤ 2) and poor in 1 patient (mRS ≥ 3); late outcomes were not available for 3 patients.

CONCLUSION

Sphenoparietal sinus DAVFs are an uncommon anatomic subtype. Careful attention to angiographic detail leads to identification of the site of venous interruption and results in a high rate of surgical cure with excellent clinical outcomes.

Contemporary Management of Cranial Dural Arteriovenous Fistulas

Cranial dural arteriovenous fistulas (dAVFs) are rare acquired neurovascular disorders that have the potential to profoundly alter the local and global cerebral venous drainage. Factors such as location, angioarchitecture, degree of shunting, and mode of presentation all appear to have some bearing on the natural history of dAVFs, which can vary from almost entirely benign to life-threatening. Accurate and evidence-based risk stratification is, therefore, key to informing important management decisions. The treatment strategies are nuanced and, for an already rare entity, can vary tremendously from 1 fistula to another. It is only through a thorough understanding of their behavior and the treatment options available that we will be able to deliver tailored treatment to the correct dAVF and the correct patient. We aimed to provide an up-to-date summary of the reported data on the natural history and predictors of aggressive behavior for cranial dAVFs in general, followed by site-specific management considerations.

Intervention for unruptured high-grade intracranial dural arteriovenous fistulas: a multicenter study

OBJECTIVE

The risk-to-benefit profile of treating an unruptured high-grade dural arteriovenous fistula (dAVF) is not clearly defined. The aim of this multicenter retrospective cohort study was to compare the outcomes of different interventions with observation for unruptured high-grade dAVFs.

METHODS

The authors retrospectively reviewed dAVF patients from 12 institutions participating in the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR). Patients with unruptured high-grade (Borden type II or III) dAVFs were included and categorized into four groups (observation, embolization, surgery, and stereotactic radiosurgery [SRS]) based on the initial management. The primary outcome was defined as the modified Rankin Scale (mRS) score at final follow-up. Secondary outcomes were good outcome (mRS scores 0-2) at final follow-up, symptomatic improvement, all-cause mortality, and dAVF obliteration. The outcomes of each intervention group were compared against those of the observation group as a reference, with adjustment for differences in baseline characteristics.

RESULTS

The study included 415 dAVF patients, accounting for 29, 324, 43, and 19 in the observation, embolization, surgery, and SRS groups, respectively. The mean radiological and clinical follow-up durations were 21 and 25 months, respectively. Functional outcomes were similar for embolization, surgery, and SRS compared with observation. With observation as a reference, obliteration rates were higher after embolization (adjusted OR [aOR] 7.147, p = 0.010) and surgery (aOR 33.803, p < 0.001) and all-cause mortality was lower after embolization (imputed, aOR 0.171, p = 0.040). Hemorrhage rates per 1000 patient-years were 101 for observation versus 9, 22, and 0 for embolization (p = 0.022), surgery (p = 0.245), and SRS (p = 0.077), respectively. Nonhemorrhagic neurological deficit rates were similar between each intervention group versus observation.

CONCLUSIONS

Embolization and surgery for unruptured high-grade dAVFs afforded a greater likelihood of obliteration than did observation. Embolization also reduced the risk of death and dAVF-associated hemorrhage compared with conservative management over a modest follow-up period. These findings support embolization as the first-line treatment of choice for appropriately selected unruptured Borden type II and III dAVFs.

Observation Versus Intervention for Low-Grade Intracranial Dural Arteriovenous Fistulas

BACKGROUND

Low-grade intracranial dural arteriovenous fistulas (dAVF) have a benign natural history in the majority of cases. The benefit from treatment of these lesions is controversial.

OBJECTIVE

To compare the outcomes of observation versus intervention for low-grade dAVFs.

METHODS

We retrospectively reviewed dAVF patients from institutions participating in the CONsortium for Dural arteriovenous fistula Outcomes Research (CONDOR). Patients with low-grade (Borden type I) dAVFs were included and categorized into intervention or observation cohorts. The intervention and observation cohorts were matched in a 1:1 ratio using propensity scores. Primary outcome was modified Rankin Scale (mRS) at final follow-up. Secondary outcomes were excellent (mRS 0-1) and good (mRS 0-2) outcomes, symptomatic improvement, mortality, and obliteration at final follow-up.

RESULTS

The intervention and observation cohorts comprised 230 and 125 patients, respectively. We found no differences in primary or secondary outcomes between the 2 unmatched cohorts at last follow-up (mean duration 36 mo), except obliteration rate was higher in the intervention cohort (78.5% vs 24.1%, P < .001). The matched intervention and observation cohorts each comprised 78 patients. We also found no differences in primary or secondary outcomes between the matched cohorts except obliteration was also more likely in the matched intervention cohort (P < .001). Procedural complication rates in the unmatched and matched intervention cohorts were 15.4% and 19.2%, respectively.

CONCLUSION

Intervention for low-grade intracranial dAVFs achieves superior obliteration rates compared to conservative management, but it fails to improve neurological or functional outcomes. Our findings do not support the routine treatment of low-grade dAVFs.

Dural Arteriovenous Fistula within Superior Sagittal Sinus Wall with Direct Cortical Venous Drainage: A Systematic Literature Review

Dural arteriovenous fistulas (DAVFs) located within superior sagittal sinus (SSS) wall with direct cortical venous drainage are rare. They are also known as variant DAVF (vDAVF) and form a special subgroup of DAVFs. Their chance of presenting with aggressive features is high compared with transverse sigmoid sinus fistula. They drain directly into cortical veins (Borden type 3, Cognard type III and IV). A systematic English literature review of SSS vDAVF was made. Systematic literature review revealed a total of 31 published cases. These were commonly seen in male population, (24 males, 77.41%, 24/31). Average age of patients was 54 years. A total of 24 patients (77.41%, 24/31) had aggressive clinical presentations with 13 patients (41.93%, 13/31) having intracranial hemorrhages (ICH). Two patients had rebleeding (15.38%, 2/13). Middle portion of SSS was commonly involved (15 cases, 75%). A total of 25 (96.15%, 25/26) cases had patent SSS. Most of the fistulas were idiopathic (65.38%, 17/26), with trauma being a frequent etiological factor (26.92%, 7/26). Venous ectasia was seen in 19 patients (59.37%, 19/32). Middle meningeal arterial (MMA) supply was seen in all patients (100%, 26/26), with bilateral MMA supply in 21 cases (80.76%), and unilateral in 5 cases (19.23%). Twenty patients (62.50%, 20/32) received only endovascular treatment (EVT), while four patients had EVT followed by surgery (12.5%, 4/32). Transarterial route via MMA was the preferred treatment option (79.16%). Complete obliteration of fistulas was noted in all cases (100%, 30/30). No immediate complication was noted after EVT. As much as 92.30% patients showed good recovery. Thus, SSS vDAVF forms a special subgroup of DAVF, with aggressive presentation, and warrants urgent treatment. EVT is effective treatment option and can produce complete obliteration.

Facial Nerve Arterial Arcade Supply in Dural Arteriovenous Fistulas: Anatomy and Treatment Strategies

BACKGROUND AND PURPOSE

Endovascular treatment of petrous dural AVFs may carry a risk of iatrogenic facial nerve palsy if the facial nerve arterial arcade, an anastomotic arterial arch that supplies the geniculate ganglion, is not respected or recognized. Our purpose was to demonstrate that the use of a treatment strategy algorithm incorporating detailed angiographic anatomic assessment allows identification of the facial nerve arterial arcade and therefore safe endovascular treatment.

MATERIALS AND METHODS

This was a retrospective cohort study of consecutive petrous dural AVF cases managed at Toronto Western Hospital between 2006 and 2018. Our standard of care consists of detailed angiographic assessment followed by multidisciplinary discussion on management. Arterial supply, primary and secondary treatments undertaken, angiographic outcomes, and clinical outcomes were assessed by 2 independent fellowship-trained interventional neuroradiologists.

RESULTS

Fifteen patients had 15 fistulas localized over the petrous temporal bone. Fistulas in all 15 patients had direct cortical venous drainage and received at least partial supply from the facial nerve arterial arcade. Following multidisciplinary evaluation, treatment was performed by endovascular embolization in 8 patients (53%) and microsurgical disconnection in 7 patients (47%). All patients had long-term angiographic cure, and none developed iatrogenic facial nerve palsy.

CONCLUSIONS

By means of our treatment strategy based on detailed angiographic assessment and multidisciplinary discussion, approximately half of our patients with petrous AVFs were cured by endovascular treatment, half were cured by an operation, and all had preserved facial nerve function.

Complication rate, cure rate, and long-term outcomes of microsurgery for intracranial dural arteriovenous fistulae: a multicenter series and systematic review

Although microsurgery is an established treatment modality for intracranial dural arteriovenous fistula (dAVF), data regarding the perioperative complication rate, cure rate, and long-term outcomes remain scarce. The aims of this study were to describe our original experience with microsurgery, including the surgical complications and pitfalls, and conduct a systematic review of the relevant literature. A multicenter cohort of patients with dAVF treated by microsurgery was retrospectively assessed. In addition, the PubMed database was searched for published studies involving microsurgery for dAVF, and the complication rate, cure rate, and long-term outcomes were estimated. The total number of patients in our multicenter series and published articles was 553 (593 surgeries). The overall rates of transient complications, permanent complications, death, and incomplete treatment were 11.4, 4.0, 1.2, and 6.5%, respectively. A favorable outcome was achieved for 90.1% patients, even though almost half of the patients presented with intracranial hemorrhage. Of note, the incidence of recurrence was only one per 8241 patient-months of postoperative follow-up. Surgeries for anterior cranial fossa dAVF were associated with a lower complication rate, whereas those for tentorial dAVF were associated with higher complication and incomplete treatment rates. The complication and incomplete treatment rates were lower with simple disconnection of cortical venous drainage than with radical occlusion/resection of dural shunts. Our findings suggest that the cure rate, complication rates, and outcomes of microsurgery for dAVF are acceptable; thus, it could be a feasible second-line treatment option for dAVF. However, surgeons should be aware of the specific adverse events of microsurgery.

Cranial dural arteriovenous shunts: selection of the ideal lesion for surgical occlusion according to the classification system

BACKGROUND

The types of cranial dural arteriovenous fistulae (cDAVFs) that constitute good surgical candidates are unclear despite the use of classifications. We aimed to compare the DES classification with other classification schemes in identifying "ideal lesions for surgery." The DES scheme is based on two features: the level of the shunt (BVS, bridging vein shunt; DSS, dural sinus shunt; ISS, isolated sinus shunt; EVS, emissary vein shunt) and the type of leptomeningeal venous reflux (LVR) (direct, exclusive, strained).

METHODS

In this observational cohort study, the angiographies of 20 consecutive patients treated over 1 year were analyzed retrospectively. We defined cDAVFs as ideal for surgery, if cure may be achieved by disconnecting the arterialized draining vein through a single craniotomy. To evaluate the performance of each classification scheme in identifying the "ideal lesion for surgery," we carried out a sensitivity analysis of the Borden, Cognard, and DES schemes.

RESULTS

Eight lesions were Borden type 3 and 1 type 2, and 11 type 1. According to Cognard, 2 lesions were type IV, 2 type III, 1 type IIa+b, 11 type I, and 4 lesions could not be clearly classified. According to the DES scheme, 8 lesions were DSS, 4 BVS, 3 ISS, and 5 EVS. All 4 lesions classified as BVS in the DES were ideal lesions for surgery (sensitivity, specificity, PPV, NPV 100%). Not all high-grade lesions according to Borden were good surgical candidates.

CONCLUSION

The DES scheme, as opposed to other classifications, facilitates the therapeutic decision-making especially for selecting candidates for surgery.

The oculomotor-tentorial triangle. Part 2: a microsurgical workspace for vascular lesions in the crural and ambient cisterns

OBJECTIVE

Pathology in the region of the basilar quadrifurcation, anterolateral midbrain, medial tentorium, and interpeduncular and ambient cisterns may be accessed anteriorly via an orbitozygomatic (OZ) craniotomy. In Part 1 of this series, the authors explored the anatomy of the oculomotor-tentorial triangle (OTT). In Part 2, the versatility of the OTT as a surgical workspace for treating vascular pathology is demonstrated.

METHODS

Sixty patients with 61 vascular pathologies treated within or via the OTT from 1998 to 2017 by the senior author were retrospectively reviewed. Patients were grouped together based on pathology/surgical procedure and included 1) aneurysms (n = 19); 2) posterior cerebral artery (PCA)/superior cerebellar artery (SCA) bypasses (n = 24); 3) brainstem cavernous malformations (CMs; n = 14); and 4) tentorial region dural arteriovenous fistulas (dAVFs; n = 4). The majority of patients were approached via an OZ craniotomy, wide sylvian fissure split, and temporal lobe mobilization to widen the OTT.

RESULTS

Aneurysm locations included the P1-P2 junction (n = 7), P2A segment (n = 9), P2/3 (n = 2), and basilar quadrification (n = 1). Aneurysm treatments included clip reconstruction (n = 12), wrapping (n = 3), proximal occlusion (n = 2), and trapping with (n = 1) or without (n = 1) bypass. Pathologies in the bypass group included vertebrobasilar insufficiency (VBI; n = 3) and aneurysms of the basilar trunk (n = 13), basilar apex (n = 4), P1 PCA (n = 2), and s1 SCA (n = 2). Bypasses included M2 middle cerebral artery (MCA)-radial artery graft (RAG)-P2 PCA (n = 8), M2 MCA-saphenous vein graft (SVG)-P2 PCA (n = 3), superficial temporal artery (STA)-P2 PCA (n = 5) or STA-s1 SCA (n = 3), s1 SCA-P2 PCA (n = 1), V3 vertebral artery (VA)-RAG-s1 SCA (n = 1), V3 VA-SVG-P2 PCA (n = 1), anterior temporal artery-s1 SCA (n = 1), and external carotid artery (ECA)-SVG-s1 SCA (n = 1). CMs were located in the midbrain (n = 10) or pontomesencephalic junction (n = 4). dAVFs drained into the tentorial, superior petrosal, cavernous, and sphenobasal sinuses. High rates of aneurysm occlusion (79%), bypass patency (100%), complete CM resection (86%), and dAVF obliteration (100%) were obtained. The overall rate of permanent oculomotor nerve palsy was 8.3%. The majority of patients in the aneurysm (94%), CM (93%), and dAVF (100%) groups had stable or improved modified Rankin Scale scores.

CONCLUSIONS

The OTT is an important anatomical triangle and surgical workspace for vascular lesions in and around the crural and ambient cisterns. The OTT can be used to approach a wide variety of vascular pathologies in the region of the basilar quadrifurcation and anterolateral midbrain.

Reconsidering an important subclass of high-risk dural arteriovenous fistulas for stereotactic radiosurgery

OBJECTIVE

Aggressive dural arteriovenous fistulas (dAVFs) with cortical venous drainage (CVD) are known for their relatively high risk of recurrent neurological events or hemorrhage. However, recent natural history literature has indicated that nonaggressive dAVFs with CVD have a significantly lower prospective risk of hemorrhage. These nonaggressive dAVFs are typically diagnosed because of symptomatic headache, pulsatile tinnitus, or ocular symptoms, as in low-risk dAVFs. Therefore, the viability of stereotactic radiosurgery (SRS) as a treatment for this lesion subclass should be investigated.

METHODS

The authors evaluated their institutional experience with SRS for dAVFs with CVD for the period from 1991 to 2016, assessing angiographic outcomes and posttreatment hemorrhage rates. They subsequently pooled their results with those published in the literature and stratified the results based on the mode of clinical presentation.

RESULTS

In an institutional cohort of 42 dAVFs with CVD treated using SRS, there were no complications or hemorrhages after treatment in 19 patients with nonaggressive dAVFs, but there was 1 radiation-induced complication and 1 hemorrhage among the 23 patients with aggressive dAVFs. In pooling these cases with 155 additional cases from the literature, the authors found that the hemorrhage rate after SRS was significantly lower among the patients with nonaggressive dAVFs (0% vs 6.8%, p = 0.003). Similarly, the number of radiation-related complications was 0/124 in nonaggressive dAVF cases versus 6/73 in aggressive dAVF cases (p = 0.001). The annual rate of hemorrhage after SRS for aggressive fistulas was 3.0% over 164.5 patient-years, whereas none of the nonaggressive fistulas bled after radiosurgery over 279.4 patient-years of follow-up despite the presence of CVD.

CONCLUSIONS

Cortical venous drainage is thought to be a significant risk factor in all dAVFs. In the institutional experience described here, SRS proved to be a low-risk strategy associated with a very low risk of subsequent hemorrhage or radiation-related complications in nonaggressive dAVFs with CVD.

Hybrid Capability to Integrate Multiple Treatment Modalities for Managing High-Grade Intracranial Dural Arteriovenous Fistulas

BACKGROUND

An integrated multimodality approach can be effective in treatment of high-grade dural arteriovenous fistulas. Nevertheless, this requires a high level of efficient cooperation between different departments, underlying a degree of bias in the decisional process. In comparison, hybrid capability, integrating these modalities in one hand, may allow aggregating multimodality treatment strategies by pooling their individual benefits, leading to a more holistic view of the consequences of each modality.

METHODS

We retrospectively reviewed 18 cases of dural arteriovenous fistulas subjected to a hybrid treatment approach at the Diakonieklinikum Jung-Stilling, Siegen, Germany, between March 2008 and January 2017. Nine cases were excluded. We selected 4 cases that highlight different aspects of hybrid capability for illustrative purposes.

RESULTS

Hybrid capability allows treatment of a dural arteriovenous fistula based on the individual clinical situation of the patient and features of the lesion, free of interdepartmental bias. The surgeon maintains a level of flexibility that enables him or her to move from a minimally invasive endovascular approach to a maximally invasive surgical access according to the specific situation. Hybrid capability can lead to a highly efficient treatment regimen with palliation of symptoms and complete obliteration of the fistula, improving performance in these complex pathologies.

CONCLUSIONS

Hybrid capability has great potential in the treatment of complex neurovascular lesions. It remains to be seen if a single surgeon with hybrid capability can supersede the current multidepartmental practice and achieve better outcomes.

Hybrid Operating Room Settings for Treatment of Complex Dural Arteriovenous Fistulas

OBJECTIVE

Dural arteriovenous fistulas (dAVFs) are abnormal direct shunts between the occipital or meningeal artery and a meningeal vein or dural venous sinus. Treatment strategies include endovascular, microsurgical, stereotactic radiosurgical, or combined interventions. With few previous reports focused on dAVF treatment in a hybrid operating room (hOR), the authors reviewed their 6-year experience in this unique setting for these complex fistulas.

METHODS

Patients with complex cerebral dAVFs underwent endovascular and microsurgical treatment in the hOR. In this retrospective review, 8 consecutive patients with cerebral dAVFs (Borden type 2 or higher) underwent endovascular and microsurgical treatment. Demographic characteristics, symptoms related to the dAVF, preoperative angiographic features, preinterventional therapies, intraoperative digital subtraction angiography (iDSA), and postoperative clinical and radiologic findings were reviewed.

RESULTS

Of these 8 patients, 5 patients underwent multiple embolizations (up to 3) and hybrid procedures, with no procedure-related complications. After microsurgical resection, iDSA revealed remnants of the fistula, which was then immediately re-resected, in 2 patients. At closing of the hybrid procedure, iDSA revealed no fistula remnants in 7 patients (88%). At mean follow-up examination (58 months), 5 patients (62%) had cure of the dAVF, confirmed by noninvasive angiography. Two patients (25%) experienced a recurrence of the dAVF within 5 months.

CONCLUSIONS

Our hybrid techniques achieved high rates of dAVF obliteration, with all 8 patients achieving good or excellent outcomes and symptom relief. Angiographic follow-up within 6 months after the hybrid procedure is recommended for all patients even when intraoperative findings do not show remnants.

Dural Arteriovenous Fistulas at the Petrous Apex

OBJECTIVE

Dural arteriovenous fistulas (DAVFs) at the petrous apex are rare but may cause subarachnoid hemorrhage (SAH) or severe brainstem edema. This study aimed to summarize their clinical features and discuss the classification.

METHODS

During a 15-year period, 64 consecutive patients with DAVF at the petrous apex were reviewed. According to their angioarchitecture, these cases were classified as follows: type I, no venous ectasia (48.4%); type II, venous ectasia but with normal vein proximal to the fistula (29.7%); and type III, venous ectasia at the site of the fistula (21.9%).

RESULTS

There were 53 men and 11 women included. Presented symptoms were SAH in 8 patients (12.5%), nonhemorrhagic neurologic defects (NHNDs) in 53 patients (82.8%), and no symptoms in 3 patients (4.7%). There were 49 patients who received transarterial embolization, 8 patients who received microsurgery, and 7 patients who received embolization and microsurgery. Complications occurred in 9 patients (14.1%), including transient cranial nerve palsy (4.7%), rebleeding (6.3%), and respiratory failure (3.1%). Of the type I patients, 96.77% presented with NHNDs and 77.42% presented with infratentorial drainage. However, SAH occurred more often in type II (21.05%)/type III cases (28.57%), and most patients carried a supratentorial drainage (63.16% and 85.71%, respectively). In different types of DAVFs, the necessity for embolization combined with microsurgery (6.45% in type I, 10.53% in type II, 21.43% in type III) and the occurrence of rebleeding complications (0% in type I, 10.53% in type II, and 14.29% in type III) were varied.

CONCLUSIONS

Petrous apex DAVFs carried a high risk of embolization-related complications. Based on the vascular architecture, this classification may reflect their clinical features and provide some advice on the treatment of DAVFs at the petrous apex.

Surgical management of superior petrosal sinus dural arteriovenous fistulae with dominant internal carotid artery supply

Background While technological advances have improved the efficacy of endovascular techniques for tentorial dural arteriovenous fistulae (DAVF), superior petrosal sinus (SPS) DAVF with dominant internal carotid artery (ICA) supply frequently require surgical intervention to achieve a definitive cure. Methods To compare the angiographic and clinical outcomes of endovascular and surgical interventions in patients with SPS DAVF, the records of all patients with tentorial DAVF from August 2010 to November 2015 were reviewed. Results Within this cohort, eight patients with nine SPS DAVF were eligible for evaluation. Five DAVF were initially treated with endovascular embolization, while four underwent surgical occlusion without embolization. Of the SPS DAVF treated with embolization, two (40%) remained occluded on follow-up, while the remaining three (60%) persisted/recurred and required surgical intervention for definitive closure. Of the four SPS DAVF treated with primary surgical occlusion, all four (100%) remained closed on follow-up. In addition, of the three SPS DAVF that persisted/recurred following embolization and required subsequent surgical closure, all three (100%) remained occluded on follow-up. Two (100%) SPS DAVF that were successfully treated with embolization had major or minor external carotid artery supply, while the three (100%) persistent lesions had major ICA supply via the meningohypophyseal trunk (MHT). Three (75%) of the four SPS DAVF treated with primary surgical occlusion had dominant MHT supply. Conclusion Complete endovascular closure of SPS DAVF with dominant ICA supply via the MHT may be difficult to achieve, while upfront surgical intervention is associated with a high rate of complete occlusion.

Spontaneous Resolution of Venous Aneurysms After Transarterial Embolization of a Variant Superior Sagittal Sinus Dural Arteriovenous Fistula: Case Report and Literature Review

We present a rare case of dural arteriovenous fistula (DAVF) with subarachnoid hemorrhage and intraventricular hemorrhage due to its venous aneurysms. A 63-year-old woman was admitted for a sudden loss of consciousness. Computed tomography angiograph, magnetic resonance imaging angiography, and digital subtraction angiography revealed a superior sagittal sinus DAVF. The fistula was fed by the left middle meningeal artery and left internal carotid artery, and was drained by a right vein of Trolard, the superficial Sylvian vein, deep Sylvian vein, and basal vein to the vein of Galen. The drainage veins were enlarged obviously with 3 aneurysmal venous malformations. There was a stenosis segment on the right basal vein. All the anatomic factors of direct cortical vein drainage, normal deep vein drainage, long tortuous drainage vein, outflow restriction, and multiple venous aneurysms, were contributed to the aggressive presentation of our case. Transarterial complete embolization of the fistula with balloon protection was successfully performed. Nine months later, a follow-up magnetic resonance imaging showed a complete disappearance of the 2 venous aneurysms located in the deep Sylvian vein and basal vein, and an obvious decrease in size of the venous aneurysm of the superficial Sylvian vein. This is the first report of a DAVF with 3 ballooned venous aneurysms and a spontaneous anatomy resolution of the venous aneurysms after the embolization of the fistula. At the same time, the clinical and radiologic characteristics of variant superior sagittal sinus DAVFs were summarized by review of the literatures reported previously.

Clinical and angioarchitectural factors influencing the endovascular approach to galenic dural arteriovenous fistulas in adults: case series and review of the literature

BACKGROUND

Galenic dural arteriovenous fistulas (DAVF) are rare; however, they are the most frequent type of DAVF to manifest aggressive clinical behavior and usually represent a diagnostic and therapeutic challenge for clinicians.

METHODS

We retrospectively reviewed clinical and imaging data of patients managed with neuroendovascular techniques for the treatment of galenic DAVFs from 2000 to 2016. We searched the 2000-2016 English-language literature for papers discussing neuroendovascular management of galenic DAVFs, with or without companion surgical procedures.

RESULTS

Five patients were treated for galenic DAVFs during the study period (four males; mean age, 61 years). Three presented with progressive neurological deterioration due to venous congestion, two with acute intracranial hemorrhage. Three were treated by staged transarterial embolization procedures (three procedures in two, four procedures in one); two underwent a single transvenous embolization procedure. Four out of five fistulas were completely occluded. All patients improved clinically; the patient whose fistula was partially occluded remains angiographically stable at 2-year follow-up. Six reports describing 17 patients are reviewed. Embolization was performed via transvenous approach in 1/17 and transarterial approach in 16/17 with additional open surgery in 9/16. The trend toward the use of transarterial approaches is based primarily on advances on embolization techniques that allow better and more controllable penetration of the embolizing agents with improved clinical and angiographic results, as well as the technical complexity of the transvenous approach.

CONCLUSIONS

Although transarterial embolization is the preferred endovascular route for the management of most galenic DAVFs, selected cases can be successfully treated by transvenous approach.

Changing Clinical and Therapeutic Trends in Tentorial Dural Arteriovenous Fistulas: A Systematic Review

BACKGROUND AND PURPOSE

Tentorial dural arteriovenous fistulas are characterized by a high hemorrhagic risk. We evaluated trends in outcomes and management of tentorial dural arteriovenous fistulas and performed a meta-analysis evaluating clinical and angiographic outcomes by treatment technique.

MATERIALS AND METHODS

We performed a comprehensive literature search for studies on surgical and endovascular treatment of tentorial dural arteriovenous fistulas. We compared the proportion of patients undergoing endovascular, surgical, and combined endovascular/surgical management; the proportion of patients presenting with ruptured tentorial dural arteriovenous fistulas; and proportion of patients with good neurologic outcome across 3 time periods: 1980-1995, 1996-2005, and 2006-2014. We performed a random-effects meta-analysis, evaluating the rates of occlusion, long-term good neurologic outcome, perioperative morbidity, and resolution of symptoms for the 3 treatment modalities.

RESULTS

Twenty-nine studies with 274 patients were included. The proportion of patients treated with surgical treatment alone decreased from 38.7% to 20.4% between 1980-1995 and 2006-2014. The proportion of patients treated with endovascular therapy alone increased from 16.1% to 48.0%. The proportion of patients presenting with ruptured tentorial dural arteriovenous fistulas decreased from 64.4% to 43.6%. The rate of good neurologic outcome increased from 80.7% to 92.9%. Complete occlusion rates were highest for patients receiving multimodality treatment (84.0%; 95% CI, 72.0%-91.0%) and lowest for endovascular treatment (71.0%; 95% CI, 56.0%-83.0%; P < .01). Long-term good neurologic outcome was highest in the endovascular group (89.0%; 95% CI, 80.0%-95.0%) and lowest for the surgical group (73.0%; 95% CI, 51.0%-87.0%; P = .03).

CONCLUSIONS

Patients with tentorial dural arteriovenous fistulas are increasingly presenting with unruptured lesions, being treated endovascularly, and experiencing higher rates of good neurologic outcomes. Endovascular treatment was associated with superior neurologic outcomes but lower occlusion rates.

Spontaneous resolution of a flow-related ophthalmic-segment aneurysm after treatment of anterior cranial fossa dural arteriovenous fistula

BACKGROUND

The natural history of proximal, feeding-artery aneurysms after successful obliteration of high-grade, anterior cranial fossa dural arteriovenous fistulas (dAVFs) has not been well documented.

CASE DESCRIPTION

A 52-year-old Caucasian male presented with an unruptured anterior cranial fossa (dAVF) and an associated aneurysm. Cerebral angiography revealed a large, contralateral, carotid-ophthalmic segment aneurysm, enlarged feeding ophthalmic arteries, as well as cortical venous drainage. Successful surgical obliteration of the dAVF was undertaken to eliminate the risk of hemorrhage.

CONCLUSION

The carotid-ophthalmic aneurysm regressed significantly after surgical obliteration of the dAVF and a follow-up, planned coiling procedure to address the carotid-ophthalmic aneurysm was abandoned. This represents the first reported case of a near complete, spontaneous resolution of an unruptured carotid-ophthalmic aneurysm associated with a high-grade anterior cranial fossa dAVF.

Dural arteriovenous fistula presenting with exophthalmos and seizures

Concomitant seizures and exophthalmos in the context of a temporal dural arteriovenous fistula (dAVF) has not been described before. Here, we report a 55-year-old-male who presented with an 8-month history of progressive painless exophthalmos of his left eye, conjunctival chemosis, reduced vision and new onset complex partial seizures. Cerebral angiography demonstrated Cognard Type IIa left cerebral dAVF fed by branches from the left occipital artery and an accessory meningeal artery, with drainage to the superior ophthalmic vein. Following surgical obliteration of dAVF feeding vessels, our patient had dramatic improvement in visual acuity, proptosis and chemosis along with cessation of clinical seizures.

Advances in Surgical Approaches to Dural Fistulas

Dural arteriovenous fistulas are abnormal connections of dural arteries to dural veins or venous sinuses originating from within the dural leaflets. They are usually located near or within the wall of a dural venous sinus that is frequently obstructed or stenosed. The dural fistula sac is contained within the dural leaflets, and drainage can be via a dural sinus or retrograde through cortical veins (leptomeningeal drainage). Dural arteriovenous fistulas can occur at any dural sinus but are found most frequently at the cavernous or transverse sinus. Leptomeningeal venous drainage can lead to venous hypertension and intracranial hemorrhage. The various treatment options include transarterial and transvenous embolization, stereotactic radiosurgery, and open surgery. Although many of the advances in dural arteriovenous fistula treatment have occurred in the endovascular arena, open microsurgical advances in the past decade have primarily been in the tools available to the surgeon. Improvements in microsurgical and skull base approaches have allowed surgeons to approach and obliterate fistulas with little or no retraction of the brain. Image-guided systems have also allowed better localization and more efficient approaches. A better understanding of the need to simply obliterate the venous drainage at the site of the fistula has eliminated the riskier resections of the past. Finally, the use of intraoperative angiography or indocyanine green videoangiography confirms the complete disconnection of fistula while the patient is still on the operating room table, preventing reoperation for residual fistulas.