Petrous apex's dural arteriovenous fistula (DAVF) mimicking a pineal region tumour: a rare cause of Hakim triad

A dural arteriovenous fistula (DAVF) is a dural-based shunt between meningeal arteries and meningeal veins, sinuses and/or cortical veins; they have been classified and named according to the location and the flow pattern. Petrous apex DAVFs are located where the petrosal vein penetrates the dura mater into the superior petrosal sinus; there are only few cases reported in the literature, they can show an aggressive behaviour (subarachnoid haemorrhage, severe brainstem oedema) with a high mortality rate. The described case is, to the best of our knowledge, the first case of a DAVF presenting with symptoms mimicking idiopathic normal pressure hydrocephalus. After worsening of gait impairment, memory loss and urinary incontinence an urgent CT of the brain showed hydrocephalus and a hyperdense mass in the pineal region mimicking a pineal tumour; an emergent digital subtraction angiogram showed a left petrous apex Borden type III DAVF. A transvenous embolisation was performed obtaining a complete obliteration.

Endovascular Management of Intracranial Dural Arteriovenous Fistulas: Transarterial Approach

In this second of 3 review articles on the endovascular management of intracranial dural AVFs, we discuss transarterial treatment approaches. The treatment goal is to occlude the fistulous point, including the most distal portion of the arterial supply together with the most proximal portion of the draining vein (ie, the "foot" of the vein), which can be accomplished with liquid embolic agents via transarterial access. Anatomic factors to consider when assessing the safety and efficacy of a transarterial approach using liquid embolic agents include location, angioarchitecture, and proximity of arterial feeders to both the vasa nervosum of adjacent cranial nerves and the external carotid-internal carotid/vertebral artery anastomoses. Anatomic locations typically favorable for transarterial approaches include but are not limited to the transverse/sigmoid sinus, cerebral convexity, and superior sagittal sinus. In this review article, we discuss the technical approaches, outcomes, potential complications, and complication avoidance strategies for transarterial embolization.

Radiation Dose and Fluoroscopy Time of Endovascular Treatment in Patients with Intracranial Lateral Dural Arteriovenous Fistulae

Purpose

Intracranial lateral dural arteriovenous fistula (LDAVF) represents a specific subtype of cerebrovascular fistulae, harboring a potentially life-threatening risk of brain hemorrhage. Fluoroscopically guided endovascular embolization is the therapeutic gold standard. We provide detailed dosimetry data to suggest novel diagnostic reference levels (DRL).

Methods

Retrospective single-center study of LDAVFs treated between January 2014 and December 2019. Regarding dosimetry, the dose area product (DAP) and fluoroscopy time were analyzed for the following variables: Cognard scale grade, endovascular technique, angiographic outcome, and digital subtraction angiography (DSA) protocol.

Results

A total of 70 patients (19 female, median age 65 years) were included. Total median values for DAP and fluoroscopy time were 325 Gy cm² (25%/75% percentile: 245/414 Gy cm²) and 110 min (68/142min), respectively. Neither median DAP nor fluoroscopy time were significantly different when comparing low-grade with high-grade LDAVF (Cognard I + IIa versus IIb–V; p > 0.05, each). Transvenous coil embolization yielded the lowest dosimetry values, with significantly lower median values when compared to a combined transarterial/transvenous technique (DAP 290 Gy cm² versus 388 Gy cm², p = 0.031; fluoroscopy time 85 min versus 170 min, p = 0.016). A significant positive correlation was found between number of arterial feeders treated by liquid embolization and both DAP (r_s = 0.367; p = 0.010) and fluoroscopy time (rs = 0.295; p = 0.040). Complete LDAVF occlusion was associated with transvenous coiling (p = 0.001). A low-dose DSA protocol yielded a 20% reduction of DAP (p = 0.021).

Conclusion

This LDAVF study suggests several local DRLs which varied substantially dependent on the endovascular technique and DSA protocol.

Posterior Fossa Dural Arteriovenous Fistulas with Subarachnoid Venous Drainage: Outcomes of Endovascular Treatment

BACKGROUND AND PURPOSE

Dural AVFs located in the posterior fossa are a rare entity. The objectives of the study were to analyze the anatomy of dural AVFs, their endovascular treatment strategies, and clinical outcomes.

MATERIALS AND METHODS

Two centers retrospectively selected patients treated between January 2009 and June 2018 having posterior fossa dural AVFs. We collected patient demographics, clinical presentation, arterial and venous outflow anatomy of the dural AVFs, and treatment outcomes.

RESULTS

Twenty-six patients treated endovascularly for posterior fossa dural AVFs, type III, IV, or V, were included. One hundred percent of the dural AVFs were occluded. A transarterial approach was performed in 23 dural AVFs (88.5%); a combined transarterial and transvenous approach, for 2 dural AVFs (7.7%); and a transvenous approach alone, for 1 dural AVF (3.8%). The middle meningeal artery was the most common artery chosen to inject embolic liquid (46%, 12/26). Procedure-related morbidity was 15.4% at 24 hours, 7.7% at discharge, and 0% at 6 months. Procedure-related mortality was 0%.

CONCLUSIONS

Endovascular treatment offers high occlusion rates for posterior fossa dural AVFs with low morbidity and mortality rates. The arterial approach is the first-line preferred approach, even if a transvenous or combined approach would be a safe and effective option for patients with favorable anatomy.

Clinical importance of the occipital artery in vascular lesions: A review of the literature

The occipital artery (OA) is a critical artery in vascular lesions. However, a comprehensive review of the importance of the OA is currently lacking. In this study, we used the PubMed database to perform a review of the literature on the OA to increase our understanding of its role in vascular lesions. We also provided our typical cases to illustrate the importance of the OA. The OA has several variations. For example, it may arise from the internal carotid artery or anastomose with the vertebral artery. Therefore, the OA may provide a crucial collateral vascular supply source and should be preserved in these cases. The OA is a good donor artery. Consequently, it is used in extra- to intracranial bypasses for moyamoya disease (MMD) or aneurysms. The OA can be involved in dural arteriovenous fistula (DAVF) and is a feasible artery for the embolisation of DAVF. True aneurysms and pseudoaneurysms can occur in the OA; surgical resection and embolisation are the effective treatment approaches. Direct high-flow AVF can occur in the OA; embolisation treatment is a good option in such cases. The OA can also be involved in MMD and brain arteriovenous malformation (AVM) by forming transdural collaterals. For a patient in the prone position, if occipital and suboccipital craniotomies are performed, the OA can also be used for intraoperative angiography. In brief, the OA is a very important artery in vascular lesions.

Dural Arteriovenous Fistula Arising after Intracranial Surgery in Posterior Fossa of Nondominant Sinus: Two Cases and Literature Review

The results of recent clinical and experimental studies suggest that the most important factor associated with the pathogenesis of dural arteriovenous fistula (AVF) is sinus thrombosis and subsequent venous or intrasinus hypertension. Here, we describe two patients who each developed a dural AVF after a posterior fossa craniotomy on the side of the nondominant or hypoplastic transverse (TS)-sigmoid (SS) sinuses. A 63-year-old female underwent surgical resection of a meningioma in the left cerebellopontine angle. Preoperative subtraction digital angiography (DSA) revealed a hypoplastic, ipsilateral left TS-SS and the sinus occlusion was revealed after surgery. Sixteen months later, she presented with a progressive left retroauricular, pulse-synchronous bruit. An AVF in the left TS-SS region was diagnosed by DSA and treated with transvenous coil embolization. The patient recovered without neurological deterioration. A 56-year-old female underwent surgical removal of an epidermoid tumor in the right cerebellopontine angle. Preoperative DSA revealed severe, ipsilateral right TS stenosis and the sinus occlusion was revealed after surgery. Two years later, she presented with the progressive right retroauricular, pulse-synchronous bruit, which was diagnosed by DSA as dural AVF in the right TS-SS region. She was treated with transvenous coil embolization and recovered without neurological deterioration. Sinus manipulation during intracranial surgery carries a potential risk of dural AVF development and this should be carefully considered, even when the ipsilateral TS-SS is nondominant or appears hypoplastic.

Clinical importance of the posterior meningeal artery: a review of the literature

The posterior meningeal artery, which arises from the vertebral artery, is a critical artery in neurological lesions. However, a comprehensive review of the importance of the posterior meningeal artery is currently lacking. In this study, we used the PubMed database to perform a review of the literature on the posterior meningeal artery to increase our understanding of its role in vascular lesions. The posterior meningeal artery provides the main blood supply to the paramedial and medial portions of the dura covering the cerebellar convexity. The posterior meningeal artery is often involved in dural arteriovenous fistulas occurring near the posterior fossa, and the posterior meningeal artery can be the path for transarterial embolisation or a path through which to monitor the degree of dural arteriovenous fistula embolisation. In posterior circulation ischaemia and moyamoya disease, the posterior meningeal artery can form transdural anastomoses with pial arteries at the surface of the brain, and these can help prevent ischemia. The posterior meningeal artery can also develop aneurysms, most of which are traumatic pseudoaneurysms; patients should therefore be treated in a timely manner or followed up carefully in cases of rebleeding. In addition, during a craniotomy, the posterior meningeal artery should be protected intraoperatively to avoid damaging any transdural anastomosis that may be present. In addition, when the posterior meningeal artery is the main feeding artery of an intracranial tumour, that artery is a satisfactory path for preoperative embolisation. Briefly, the posterior meningeal artery is a very important artery in neurosurgery.

Cranial Nerve Palsy after Onyx Embolization as a Treatment for Cerebral Vascular Malformation

The Onyx liquid embolic system is a relatively safe and commonly used treatment for vascular malformations, such as arteriovenous fistulas and arteriovenous malformations. However, studies on possible complications after Onyx embolization in patients with vascular malformations are limited, and the occurrence of cranial nerve palsy is occasionally reported. Here we report the progress of two different types of cranial nerve palsy that can occur after embolization. In both cases, Onyx embolization was performed to treat vascular malformations and ipsilateral oculomotor and facial nerve palsies were observed. Both patients were treated with steroids and exhibited symptom improvement after several months. The most common types of neuropathy that can occur after Onyx embolization are facial nerve palsy and trigeminal neuralgia. Although the mechanisms underlying these neuropathies are not clear, they may involve traction injuries sustained while extracting the microcatheter, mass effects resulting from thrombi and edema, or Onyx reflux into the vasa nervorum. In most cases, the neuropathy spontaneously resolves several months following the procedure.

Treatment of cranial dural arteriovenous fistulas with exclusive cortical venous drainage: A single-center cohort of 35 patients

Background and purpose Dural arteriovenous fistulas (DAVFs) with cortical venous drainage often present with hemorrhage or neurological deficits and prompt treatment is indicated. Disconnection of the draining vein is considered curative. We present the multimodality treatment results of 35 patients with cranial DAVFs with exclusive cortical venous drainage. Materials and methods Between January 2010 and January 2017, 35 consecutive patients with cranial dural fistulas with exclusive cortical venous drainage were treated. There were 27 men and eight women, mean age 68 years (range 45-87). Clinical presentation was hemorrhage in 23 (66%), pulsatile bruit in two (6%), seizures in one (3%) and blurred vision in one (3%). In eight patients (22%), the DAVF was an incidental finding. Location of the DAVFs was convexity in 25 (71%), posterior fossa in eight (23%) and tentorium in two (6%). Results Surgery was performed in four patients with anterior cranial fossa fistulas and in one patient with a tentorial dural fistula. In 30 patients, embolization with Onyx via the arterial route was the primary treatment with complete obliteration in one session in 25 patients. Additional surgical or endovascular sessions were necessary in five patients after incomplete embolization and in one patient after incomplete surgery. Obliteration was confirmed with angiography after three months. There were no procedural complications. Conclusions Patients with dural fistulas with cortical venous drainage were cured with a strategy of arterial endovascular treatment with Onyx and surgery. These techniques were either primarily successful or complementary. There were no complications of treatment.

Quantifying the Cerebral Hemodynamics of Dural Arteriovenous Fistula in Transverse Sigmoid Sinus Complicated by Sinus Stenosis: A Retrospective Cohort Study

BACKGROUND AND PURPOSE

Sinus stenosis occasionally occurs in dural arteriovenous fistulas. Sinus stenosis impedes venous outflow and aggravates intracranial hypertension by reversing cortical venous drainage. This study aimed to analyze the likelihood of sinus stenosis and its impact on cerebral hemodynamics of various types of dural arteriovenous fistulas.

MATERIALS AND METHODS

Forty-three cases of dural arteriovenous fistula in the transverse-sigmoid sinus were reviewed and divided into 3 groups: Cognard type I, type IIa, and types with cortical venous drainage. Sinus stenosis and the double peak sign (occurrence of 2 peaks in the time-density curve of the ipsilateral drainage of the internal jugular vein) in dural arteriovenous fistula were evaluated. "TTP" was defined as the time at which a selected angiographic point reached maximum concentration. TTP of the vein of Labbé, TTP of the ipsilateral normal transverse sinus, trans-fistula time, and trans-stenotic time were compared across the 3 groups.

RESULTS

Thirty-six percent of type I, 100% of type IIa, and 84% of types with cortical venous drainage had sinus stenosis. All sinus stenosis cases demonstrated loss of the double peak sign that occurs in dural arteriovenous fistula. Trans-fistula time (2.09 seconds) and trans-stenotic time (0.67 seconds) in types with cortical venous drainage were the most prolonged, followed by those in type IIa and type I. TTP of the vein of Labbé was significantly shorter in types with cortical venous drainage. Six patients with types with cortical venous drainage underwent venoplasty and stent placement, and 4 were downgraded to type IIa.

CONCLUSIONS

Sinus stenosis indicated dysfunction of venous drainage and is more often encountered in dural arteriovenous fistula with more aggressive types. Venoplasty ameliorates cortical venous drainage in dural arteriovenous fistulas and serves as a bridge treatment to stereotactic radiosurgery in most cases.

Spontaneous Aggressive Conversion of Venous Drainage Pattern in Dural Arteriovenous Fistula Treated with Onyx Embolization

We report a case of dural arteriovenous fistula (DAVF) that showed spontaneous conversion of venous drainage pattern from Borden type II to type III within a four month period of follow-up. Upon admission, the patient presented with aggravated neurologic status and newly developed seizure. After admission, endovascular embolization was performed through the middle meningeal artery with Onyx®. Complete obliteration of dural arteriovenous shunt was confirmed by angiography, and the patient's clinical symptoms improved. Although most cases of DAVF show benign clinical course and conversion pattern, close follow-up is required to detect potential aggravation.

Dural Arteriovenous Fistulae: Imaging and Management

Intracranial dural arteriovenous fistulae (DAVF) are pathologic arteriovenous shunts between meningeal arteries and dural venous sinuses or veins. They account for approximately 10% to 15% of all intracranial vascular malformations and are most common in middle-aged patients. DAVF are the most common vascular cause of pulsatile tinnitus. Digital subtraction angiography remains the gold standard for diagnosing these lesions. The pattern of venous drainage determines the type of DAVF and their risk for hemorrhage. Endovascular treatment has become a first-line option for their management. This article describes the natural history, clinical presentation, classification, imaging features, and management options of intracranial DAVF.

Transarterial onyx embolization of cranial dural arteriovenous fistulas: long-term follow-up

BACKGROUND AND PURPOSE

Endovascular therapy with liquid embolic agents is a common treatment strategy for cranial dural arteriovenous fistulas. This study evaluated the long-term effectiveness of transarterial Onyx as the single embolic agent for curative embolization of noncavernous cranial dural arteriovenous fistulas.

MATERIALS AND METHODS

We performed a retrospective review of 40 consecutive patients with 41 cranial dural arteriovenous fistulas treated between March 2006 and June 2012 by using transarterial Onyx embolization with intent to cure. The mean age was 57 years; one-third presented with intracranial hemorrhage. Most (85%) had cortical venous drainage. Once angiographic cure was achieved, long-term treatment effectiveness was assessed with DSA and clinical follow-up.

RESULTS

Forty-nine embolization sessions were performed; 85% of cranial dural arteriovenous fistulas were treated in a single session. The immediate angiographic cure rate was 95%. The permanent neurologic complication rate was 2% (mild facial palsy). Thirty-five of the 38 patients with initial cure underwent short-term follow-up DSA (median, 4 months). The short-term recurrence rate was only 6% (2/35). All patients with occlusion at short-term DSA undergoing long-term DSA (median, 28 months) had durable occlusion. No patient with long-term clinical follow-up (total, 117 patient-years; median, 45 months) experienced hemorrhage.

CONCLUSIONS

Transarterial embolization with Onyx as the single embolic agent results in durable long-term cure of noncavernous cranial dural arteriovenous fistulas. Recurrence rates are low on short-term follow-up, and all patients with angiographic occlusion on short-term DSA follow-up have experienced a durable long-term cure. Thus, angiographic cure should be defined at short-term follow-up angiography instead of at the end of the final embolization session. Finally, long-term DSA follow-up may not be necessary if occlusion is demonstrated on short-term angiographic follow-up.

Brainstem Congestion due to Dural Ateriovenous Fistula at the Craniocervical Junction

Dural ateriovenous fistula (DAVF) at the craniocervical junction is rare. We report a patient presenting with brainstem dysfunction as an uncommon onset. Brainstem lesion was suggested by magnetic resonance image study. Angiogram revealed a DAVF at a high cervical segment supplied by the meningeal branch of the right vertebral artery, with ascending and descending venous drainage. Complete obliteration of the fistula was achieved via transarterial Onyx embolization. Clinical cure was achieved in the follow-up period; meanwhile, imaging abnormalities of this case disappeared. Accordingly, we hypothesize that a brainstem lesion of this case was caused by craniocervical DAVF, which induced venous hypertension. Thus, venous drainage patterns should be paid attention to because they are important for diagnosis and theraputic strategy.

Mid and long term outcomes of dural arteriovenous fistula endovascular management with Onyx. Experience of a single tertiary center

INTRODUCTION

The natural history of intracranial dural arteriovenous fistulas (DAVFs) with cortical venous drainage is unfavorable, and treatment is recommended in most cases. Early reports have documented excellent initial clinical and radiographic outcomes after Onyx embolization of DAVFs but little evidence is available regarding the long term durability of this technique.

METHODS

We retrospectively reviewed a database of 63 DAVFs in 53 consecutive patients who underwent Onyx embolization of a DAVF between 2001 and 2012 at our institution. Cognard types I and III were seen most commonly.

RESULTS

A total of 72 Onyx embolization procedures were successfully completed during the study period, resulting in complete or near complete occlusion by the end of the study period in 58 (92.1%) DAVFs. For DAVFs in which complete or near complete obliteration was attained, stability of obliteration at 6, 12, 24, and 46 months was 100%, 95.4%, 93.8%, and 92.3%, respectively. DAVF recanalization/regrowth was discovered on delayed follow-up angiography in only five instances in which immediate post-embolization angiography revealed complete obliteration. Complications were seen in seven embolization procedures and included cranial nerve palsies (n=3), embolic infarcts (n=2), intraparenchymal hemorrhage (n=1), and unintentional stent deployment (n=1).

CONCLUSIONS

Early evidence has indicated that endovascular Onyx embolization is safe and effective at achieving an initial angiographic cure. Results of our series suggest that angiographic and clinical outcomes of Onyx embolization remain relatively stable at mid and long term follow-up.

Dural arteriovenous fistula involving an isolated sinus treated using transarterial onyx embolization

The authors present a case of isolated dural arteriovenous fistula (DAVF) in the transverse sinus, which developed six years after microvascular decompression caused by hemifacial spasm via suboccipital craniectomy. The lesion was successfully treated by transarterial embolization using Onyx. We reviewed the related radiologic and therapeutic features of DAVF involving an isolated sinus and described the feasibility of the use of Onyx.

Recurrence of "cured" dural arteriovenous fistulas after Onyx embolization

Endovascular embolization with Onyx has been increasingly used to treat intracranial and spinal dural arteriovenous fistulas (DAVFs). Several case series have been published in recent years reporting high DAVF cure rates with this technique. Although it is seldom reported, DAVF recurrence may occur despite initial "cure." The authors present 3 separate cases of a recurrent DAVF after successful transarterial Onyx embolization. Despite adequate Onyx penetration into the fistula and draining vein, these cases demonstrate that DAVF recanalization may reappear with filling from previous or newly recruited arterial feeders. Other published reports of DAVF recurrence are examined, and potential contributory factors are discussed. These cases highlight the need for awareness of this possible phenomenon and suggest that follow-up angiography should be considered in patients treated with catheter embolization.

Transient cranial neuropathies as sequelae of Onyx embolization of arteriovenous shunt lesions near the skull base: possible axonotmetic traction injuries

INTRODUCTION

Transarterial embolization with Onyx is a relatively safe and increasingly common method of treating cranial dural arteriovenous fistulas (DAVF) and arteriovenous malformations (AVM). Cranial neuropathy resulting from this procedure has been reported.

CASE REPORTS

Three case histories are presented in two patients treated for a DAVF and an AVM near the skull base with heavily parasitized supply from external carotid artery branches. Transarterial embolization resulted in transient cranial neuropathies including two cases of lower facial nerve palsy and one case of trigeminal nerve mandibular segment (V3) neuralgia which resolved spontaneously over a few months. Treatment of the DAVF and AVM was otherwise successful.

DISCUSSION

The most common cranial neuropathies following transarterial Onyx embolization procedures are facial nerve palsy and V3 neuralgia. The middle meningeal and internal maxillary arteries are common conduits used in dural-based and facial arteriovenous shunt lesions and are in proximity to the facial nerve and maxillary segment of the trigeminal nerve as they exit the skull base. Based on their relative frequency and anatomic proximity, it is surmised that these facial neuropathies are traction-type injuries related to microcatheter extraction from the Onyx cast.

CONCLUSIONS

Cranial neuropathies, specifically facial nerve palsy and V3 neuralgia, following transarterial Onyx embolizations are probably axonotmetic traction injuries related to microcatheter extraction. These appear to be self-limiting and resolve over a few months.

Flow control techniques for Onyx embolization of intracranial dural arteriovenous fistulae

OBJECTIVES

Experience of flow control techniques during endovascular treatment of intracranial dural arteriovenous fistulas (DAVFs) using the Onyx liquid embolic system is reported, with an emphasis on high flow shunts.

METHODS

Data were evaluated in patients with DAVFs treated endovascularly with Onyx. Adjunctive techniques with coils, acrylics and balloon assistance were utilized to reduce the rate of flow with transarterial and transvenous approaches.

RESULTS

The following types of adjunctive techniques were used in 58 patients who underwent a total of 84 embolization sessions with Onyx: transvenous coiling with transvenous or transarterial Onyx embolization in 36 patients, transarterial coiling with transarterial Onyx embolization in eight patients, arterial or venous balloon assisted technique with transarterial or transvenous Onyx embolization in 11 patients, transarterial high concentration acrylics with transarterial Onyx embolization in one patient and staged transarterial or transvenous coiling and Onyx embolization in two patients. Complete obliteration of the fistulae was achieved in 41 patients (70.7%) and 27 patients (65.9%) with high flow fistulae after endovascular treatment alone. Periprocedural complications were encountered in 16 patients, and 13 complications were associated with the adjunctive techniques. There were four neurologic and two non-neurologic clinical sequelae. Distal Onyx migration occurred in four, microcatheter retention in three and cranial neuropathy in three patients. There was one instance each of cerebellar hemorrhage, thromboembolism, coil stretching and retention, and dissection. 56 survivors experienced complete resolution or significant improvement of their symptoms on follow-up.

CONCLUSIONS

Flow control techniques are safe and effective adjunctive methods in primary endovascular Onyx embolization of high flow DAVFs.

Endovascular treatment of hemifacial spasm associated with a petrosal DAVF using transarterial Onyx embolization. A case report

This paper reports that decompression of the facial nerve by transarterial Onyx embolization may relieve hemifacial spasm (HFS) caused by dilated veins due to a right petrosal dural arteriovenous fistula (DAVF). A 56-year-old man suffered severe chronic right HFS associated with a dilated right petrosal vein lying in the vicinity of the facial nerve. The right petrosal DAVF was reached through the middle meningeal artery using a transfemoral arterial approach and was occluded with Onyx 18 (M.T.I.- ev3, Irvine, CA, USA). There was complete remission of HFS without recurrence after two months of follow-up. This case supports vascular compression in the pathogenesis of HFS and suggests that facial nerve injury caused by a DAVF could be treated with transarterial Onyx embolization.

Intracranial dural arteriovenous fistulas: classification, imaging findings, and treatment

Intracranial DAVFs are pathologic dural-based shunts and account for 10%-15% of all intracranial arteriovenous malformations. These malformations derive their arterial supply primarily from meningeal vessels, and the venous drainage is either via dural venous sinuses or through the cortical veins. DAVFs have a reported association with dural sinus thrombosis, venous hypertension, previous craniotomy, and trauma, though many lesions are idiopathic. The diagnosis is dependent on a high level of clinical suspicion and high-resolution imaging. Cross-sectional imaging techniques by using CT and MR imaging aid in the diagnosis, but conventional angiography remains the most accurate method for complete characterization and classification of DAVFs. The pattern of venous drainage observed on dynamic vascular imaging determines the type of DAVF and correlates with the severity of symptoms and the risk of hemorrhage.

A case of intraosseous dural arteriovenous fistulas involving diploic vein treated with transarterial onyx embolization

Intracranial dural arteriovenous fistulas (DAVFs) are abnormal arteriovenous connections that lie within the dura. Intraosseous DAVFs involving diploic venous system are extremely rare. A 46-year-old woman presented with headache and right pulsatile tinnitus for three weeks. The tinnitus started after yelling. Digital subtraction angiography revealed DAVF within the basal portion of right parietal bone along the middle meningeal artery (MMA) groove. The fistula was fed by frontal branch of right MMA and drained into right transverse sigmoid sinus junction through dilated middle meningeal vein. The intraosseous DAVF involving diploic vein was successfully obliterated with Onyx embolization via transarterial route.

Acute respiratory distress syndrome after onyx embolization of arteriovenous malformation

Purpose. We report a case of a 60-year-old male who underwent sequential Onyx embolizations of a cerebral arteriovenous malformation (AVM) which we implicate as the most likely etiology of subsequent acute respiratory distress syndrome (ARDS). Methods. Case report and literature review. Results. Shortly after the second Onyx embolization procedure, the patient declined from respiratory failure secondary to pulmonary edema. Clinical entities typically responsible for pulmonary edema including cardiac failure, renal failure, iatrogenic volume overload, negative-pressure pulmonary edema, and infectious etiologies were evaluated and excluded. The patient required mechanical ventilatory support for several days, delaying operative resection. The patient met clinical and radiographic criteria for ARDS. After excluding other etiologies of ARDS, we postulate that ARDS developed as a result of Onyx administration. The Onyx copolymer is dissolved in dimethyl sulfoxide (DMSO), a solvent excreted through the lungs and has been implicated in transient pulmonary side effects. Additionally, a direct toxic effect of the Onyx copolymer is postulated. Conclusion. Onyx embolization and DMSO toxicity are implicated as the etiology of ARDS given the lack of other inciting factors and the close temporal relationship. A strong physiologic rationale provides further support. Clinicians should consider this uncommon but important complication.

Intraoperative angiography for cranial dural arteriovenous fistula

BACKGROUND AND PURPOSE

IA is a valuable adjunct during surgery for a variety of neurovascular diseases; however, there are no reported series describing IA for DAVFs. This study was undertaken to evaluate the safety and efficacy of IA for DAVFs.

MATERIALS AND METHODS

A retrospective review of DAVF surgical cases during a 20-year period was conducted, and cases with IA were evaluated. Clinical details, surgical and angiographic findings, and postoperative outcomes were reviewed. The incidence of residual fistula on IAs, the utility of the surgical procedure, and the incidence of false-negative findings on IA were also determined.

RESULTS

IA was performed in 29 patients (31 DAVFs) for DAVFs. The distribution of the fistulas was the following: transverse-sigmoid (n = 9), tentorial (n = 6), torcular (n = 3), cavernous sinus (n = 4), SSS (n = 4), foramen magnum (n = 3), and temporal-middle fossa (n = 2). Twelve patients had undergone prior embolization, while 6 patients had unsuccessful embolization procedures. Thirty-eight surgeries were performed for DAVF in 29 patients, and IA was performed in 34 surgeries. Forty-four angiographic procedures were performed in the 34 surgeries. Nine patients underwent multiple angiographies. In 11 patients (37.9%), IA revealed residual fistula after the surgeon determined that no lesion remained. This led to further exploration at the same sitting in 10 patients, while in 1 patient, further surgery was performed at a later date. False-negative findings on IA occurred in 3 patients (10.7%).

CONCLUSIONS

IA is an important adjunct in surgery for DAVF. In this series, it resulted in further surgical treatment in 37.9% of patients. However, there was a 10% false-negative rate, which justified subsequent postoperative angiography.

Microsurgery can cure most intracranial dural arteriovenous fistulae of the sinus and non-sinus type

There is consensus that intracranial dural arteriovenous fistulae (dAVF) with direct (non-sinus-type) or indirect (sinus-type) retrograde filling of a leptomeningeal vein should be treated due to the high risk of neurological deficits and hemorrhage. No consensus exists on treatment modality (surgery and/or embolization) and, if surgery is performed, on the best surgical strategy. This series aims to evaluate the role of surgery in the management of aggressive dAVFs. Forty-two patients underwent surgery. Opening and packing the sinus with thrombogenic material was performed in 9 of the 12 sinus-type dAVFs. In two sinus-type fistulae of the cavernous sinus and 1 of the torcular, microsurgery was used as prerequisite for subsequent embolization by providing access to the sinus. In the 30 non-sinus-type dAVFs, surgery consisted of interruption of the draining vein at the intradural entry point. In 41 patients undergoing 43 operations, elimination of the dAVF was achieved (97.6%). In one case, a minimal venous drainage persisted after surgery. The transient surgical morbidity was 11.9% (n = 5) and the permanent surgical morbidity 7.1% (n = 3). Our surgical strategy was to focus on the arterialized leptomeningeal vein in the non-sinus-type and on the arterialized sinus segment in the sinus-type dAVFs allowing us to obliterate all but one dAVF with a low morbidity rate. We therefore propose that microsurgery should be considered early in the treatment of both types of aggressive dAVFs. In selected cases of cavernous sinus dAVFs, the role of microsurgery is reduced to that of an adjunct to endovascular therapy.

Isolated hypoglossal nerve palsy due to endovascular treatment of a dural arteriovenous fistula with Onyx-18

We describe a patient with dural arteriovenous fistula (DAVF) treated with Onyx-18 who developed isolated hypoglossal nerve palsy. This is the first case of isolated hypoglossal nerve palsy caused by Onyx-18 embolization. This complication suggests that over embolization with Onyx-18 in the treatment of hypoglossal canal DAVFs should be avoided, and transvenous embolization may be safer. Furthermore, prednisolone therapy should be carried out in the prophase of nerve palsy.

Long-term outcome in patients treated for benign dural arteriovenous fistulas of the posterior fossa

INTRODUCTION

Dural arteriovenous fistula (dAVF) draining into a dural sinus without recruitment of cortical veins is regarded as relatively benign lesion and treatment is advocated only if the patient is severely affected by the symptoms. The aim of this study was to compare the clinical outcomes in patients who received endovascular treatment or no treatment, respectively.

METHODS

Twenty-one patients presented consecutively with pulsating tinnitus as leading symptom and with angiographically proven dAVF at the transverse or sigmoid sinus (Borden I). Nine patients underwent different types of endovascular embolisation, and 12 patients were not treated. After a median follow-up period of 2.3 years, outcome was evaluated by assessing the patients' symptoms and scores on the mRS, EQ-5D, SF-36 and HIT-6 scales.

RESULTS

Complete long-term closure of the dAFV was achieved in two out of nine cases; subtotal occlusion was found in seven patients. Pulsating tinnitus persisted less frequently in treated than in untreated patients. Neurologic symptoms occurred in both groups. Neither these findings nor the clinical outcome and scores on the quality-of-life scales varied substantially between the two groups.

CONCLUSION

Partial treatment did not resolve the clinical symptoms of patients with "benign" dural AVF in the follow-up and was not clearly superior to conservative management. These results suggest that embolisation should be offered only if there is a possibility of a complete cure without major periinterventional risks. Further studies should be performed to assess the risk-benefit ratio of pursuing more aggressive treatment strategies in patients with unbearable symptoms.

[Regeneration of the facial nerve in comparison to other peripheral nerves : from bench to bedside]

Despite increasing knowledge of cellular and molecular mechanisms determining the success or failure of peripheral nerve regeneration, no effective treatments for peripheral nerve injury exist. Newly developed and validated approaches for precise numerical assessment of motor deficits have recently allowed testing of novel strategies in experimental animals. One of these approaches is the daily manual stimulation of the denervated musculature. This treatment is effective in cases of cranial nerve lesions with preservation of the sensory input (facial or hypoglossal nerve) and has the potential of direct translation in clinical settings. However, manual stimulation appears to be ineffective for the treatment of mixed peripheral nerve injuries. Generally, no long-term improvement of functional recovery is achieved by electrical stimulation in rodents. While short-term post-traumatic stimulation of the proximal nerve stump has no negative effects, direct electrical stimulation of the muscle during the period of de- and reinnervation appears to hinder muscle fibre reinnervation. Finally, experimental evidence suggests that application of peptides known as glycomimetics, which mimic functional properties of carbohydrate molecules, may provide significant benefits after injuries of mixed peripheral nerves.

Curative embolization with Onyx of dural arteriovenous fistulas with cortical venous drainage

BACKGROUND AND PURPOSE

Dural fistulas with cortical venous drainage often present with hemorrhage or neurologic deficit, and prompt treatment is indicated. Occlusion of the draining vein by endovascular techniques or surgical disconnection is considered curative. We present our first endovascular experience with use of Onyx via the arterial route in these aggressive fistulas.

MATERIALS AND METHODS

Between October 2008 and October 2009, 8 consecutive patients with a dural fistula with exclusive cortical venous drainage were treated with Onyx. Three patients presented with hemorrhage; 3, with hemianopsia; 1 with bruit; and 1 after incomplete coil occlusion of a benign sigmoid sinus dural fistula. Fistula location was the sigmoid sinus segment in 4, the occipital area in 2, the cavernous sinus in 1, and the torcula in 1.

RESULTS

In all 8 patients, it was possible to occlude the proximal venous site of the fistula with Onyx via arterial feeders, resulting in complete cure in all. In 6 patients, a prolonged (17- to 29-minute) single middle meningeal artery injection was sufficient to occlude the venous site of the fistula with retrograde occlusion of other arterial feeders; in the other 2 patients, 2 injections in supplying arteries were needed. Follow-up angiograms after 6-12 weeks confirmed lasting complete occlusion of the fistulas. All patients were clinically cured, there were no complications.

CONCLUSIONS

In this small series, curative embolization of dural fistulas with exclusive cortical venous drainage by using Onyx via the arterial route was possible in all patients.