Alfredo Casasco

Dural arteriovenous fistulas as a cause of intracranial hypertension due to impairment of cranial venous outflow

OBJECTIVES A retrospective study was carried out on 13 patients with intracranial dural arteriovenous fistulas (DAVFs) who presented with isolated or associated signs of intracranial hypertension. METHODS Nine patients presented with symptoms of intracranial hypertension at the time of diagnosis. Ocular fundoscopy available in 12 patients showed bilateral papilloedema in eight and optic disk atrophy in four. Clinical evolution was particularly noticeable in five patients because of chronic (two patients) or acute (after lumbar shunting or puncture: three patients, one death) tonsillar herniation. RESULTS Two patients had a type I fistula (drainage into a sinus, with a normal antegrade flow direction). The remaining 11 had type II fistulas (drainage into a sinus, with abnormal retrograde venous drainage into sinuses or cortical veins). Stenosis or thrombosis of the sinus(es) distal to the fistula was present in five patients. The cerebral venous drainage was abnormal in all patients. CONCLUSION Type II (and some type I) DAVFs may present as isolated intracranial hypertension mimicking benign intracranial hypertension. Normal cerebral angiography should be added as a fifth criterion of benign intracranial hypertension. The cerebral venous drainage pattern must be carefully studied by contralateral carotid and vertebral artery injections to correctly evaluate the impairment of the cerebral venous outflow. Lumbar CSF diversion (puncture or shunting) may induce acute tonsillar herniation and should be avoided absolutely. DAVF may induce intracranial hypertension, which has a poor long term prognosis and may lead to an important loss of visual acuity and chronic tonsillar herniation. Consequently, patients with intracranial hypertension must be treated, even agressively, to obliterate the fistula or at least to reduce the arterial flow and to restore a normal cerebral venous drainage. The endovascular treatment may associate arterial or transvenous embolisation and /or surgery. Patients in whom the fistula is not obliterated after an endovascular therapeutic procedure, need continous clinical and angiographical follow up.

A proposed angiographic classification of intracranial arteriovenous fistulae and malformations

We propose an angioarchitectural classification of intracranial vascular lesions as arteriovenous, arteriolovenous and arteriolovenulous fistulae. In order to validate this classification, 99 intracranial arteriovenous lesions were reviewed in 98 patients. Arteriolovenulous fistulae included 39 isolated brain arteriovenous malformations (AVMs) and 1 AVM associated with a giant arteriovenous fistula (AVF). Arteriovenous fistulae included 8 giant AVFs of the brain, 6 vein of Galen aneurysms and 10 direct caroticocavernous fistulae. Arteriolovenous fistulae included 1 isolated brain AVM, 4 vein of Galen aneurysms and 30 dural AVMs. The angioarchitectural classification has three advantages. It is simple and accurate, with no reference to the congenital or acquired nature of the lesion. It allows separate identification of a special group, the arteriolovenous fistulae. It also indicates the endovascular approach: arteriolovenulous fistulae should be treated via the arterial route only, while arteriovenous and arteriolovenous fistulae can be treated via transarterial or transvenous approaches.

Long-term changes in intracranial dural arteriovenous fistulae leading to worsening in the type of venous drainage.

Abstract We review seven patients with intracranial dural arteriovenous fistulae (ICDAVF), each altering the initial type of venous drainage to one with a higher grading during long-term follow-up. Five were discovered due to symptoms of intracranial hypertension, two due to changes in tinnitus and one case following subarachnoid haemorrhage. In five cases, cortical venous drainage developed during the follow-up period. Three different mechanisms were observed: stenosis or thrombosis in the draining veins in 4 cases: increased arterial flow in 2; and the appearance o a new fistula site or extension of the initial shunt in 2. Type I and type II a fistulae which are not completely cured, require both close clinical observation and Doppler examinations in the follow-up period. Any charge in the clinical pictures indicates a repeat angiogram. Stenosis of the venous drainage, forecasting later worsening in the venous outlet, requires more thorough angiographic follow-up.

Percutaneous Transvenous Catheterization and Embolization of Vein of Galen Aneurysms

Seven cases of vein of Galen aneurysms treated by percutaneous transvenous endovascular occlusion of the aneurysmal vein are presented. In one case, the approach was via the femoral vein, and in the other six cases, by the jugular vein. All of the malformations were multipedicular and, additionally, in six of the seven there was an intervening arterial-arterial network between the posterior thalamoperforating arteries and the wall of the venous aneurysm. This fistulous network was interpreted as purely arterial and not as an associated arteriovenous malformation. For this reason, the transvenous approach was considered justified, and was performed without risk of hemorrhage caused by retrograde venous hypertension. Measurement of intra-aneurysmal pressure during the course of treatment allowed better understanding of the hemodynamics of the lesions, guided the amount of occlusion to be accomplished during each treatment session, and thus may have prevented the phenomenon of normal perfusion pressure breakthrough. The percutaneous transvenous approach offers all the advantages of the transtorcular approach but avoids surgery. Because of our excellent angiographic and clinical results--five complete and two partial occlusions, with favorable outcomes and no major complications--we believe that this technique is better for the treatment of multipedicular vein of Galen aneurysms than transarterial embolization or surgery.

Ethanol embolization of arteriovenous fistulas: a primary mode of therapy.

Arteriovenous fistulas (AVFs) can be posttraumatic or congenital vascular malformations. In the initial arteriographic evaluation, chronic AVFs potentially can be confused with arteriovenous malformations (AVMs). The authors studied five patients with a single AVF and one patient with numerous AVFs. Three patients had undergone surgery for treatment of their AVFs, one patient had undergone isobutyl-2-cyanoacrylate (IBCA) embolization, and two patients had undergone no prior therapy. The AVFs recurred in the three patients who had undergone surgery and in the patient who had undergone IBCA embolization. All patients underwent ethanol embolization of their AVFs. Angiograms obtained immediately after embolization documented closure of all AVFs. At follow-up, none of the embolized lesions have recurred. The authors conclude that ethanol embolotherapy can cure these problematic lesions. Extreme caution, however, must be employed with the use of intravascular ethanol because nontarget embolization can potentially result in tissue devitalization. In this study, two patients developed a small focal area of skin necrosis that did not require skin grafting and healed with conservative management.

Management of intracranial aneurysms by surgical and endovascular treatment--modalities and results from a series of 395 cases.

Summary The selective occlusion of saccular intracranial aneurysms may be achieved by two techniques: microsurgical clipping and endovascular coiling. Each of them have particular indications which need to be defined. We report on a series in which both techniques were applied. From September 1992 to June 1996, 395 consecutive patients with small or large aneurysm were treated either by surgery (N=102) or by endovascular coiling (N=293). Coiling was chosen each time the shape of the aneurysm seemed to be appropriate for this treatment: narrow neck and ratio neck diameter by sac diameter less than one third. Satisfactory results with complete or subtotal obliteration and no recanalization on the following controls at 1, 6, 12 and 36 months, were obtained in 92% before retreatment and in 98.8% after retreatment. Unsatisfactory results were observed after surgery in 7 cases and in 25 cases after embolization. After retreatment, it remains 3 post-surgical and 2 post-endovascular cases. In the overall series, good and excellent clinical outcome was noted in 90% for small aneurysms and in 86.5% for large ones; mortality was of 4.8%. In a series in which were applied both types of treatment, surgery in 25% and endovascular technique in 75%, good results in terms of aneurysm occlusion and clinical results were achieved. These results are as good as the best series in which surgery was the only choice. Therefore with appropriate selection, endovascular treatment is a good alternative for treatment of the majority of saccular aneurysms.

Intratumoral embolization of intracranial and extracranial tumors: technical note.

A new technique of intratumoral embolization is described. An intratumoral injection of N-butylcyanoacrylate is performed either perioperatively by direct puncture of the tumor or preoperatively through the nose or through the skin. The indications for this technique are hypervascularized tumors, such as juvenile angiofibroma, hemangiopericytoma, or paraganglioma. This technique has been applied in 21 patients with excellent results in terms of devascularization.

Intratumoral Embolization of Intracranial and Extracranial TumorsTechnical Note

A new technique of intratumoral embolization is described. An intratumoral injection of N-butylcyanoacrylate is performed either perioperatively by direct puncture of the tumor or preoperatively through the nose or through the skin. The indications for this technique are hypervascularized tumors, such as juvenile angiofibroma, hemangiopericytoma, or paraganglioma. This technique has been applied in 21 patients with excellent results in terms of devascularization.

Endovascular treatment of a cavernous sinus dural arteriovenous fistula by transvenous embolisation through the superior ophthalmic vein via cannulation of a frontal vein

Abstract We describe a new approach for transvenous embolisation of cavernous sinus dural arteriovenous fistulae through the superior ophthalmic vein (SOV), i.e., via percutaneous cannulation of a frontal vein. Modern neurointerventional angiographic materials make it possible to reach the SOV in this way without puncturing it in the orbit or a surgical exposure. Orbital phlebography should still be in the repertoire of interventional neuroradiology units in large centres.

Percutaneous Treatment of Cervical Disk Hernias Using Gelified Ethanol

SUMMARY: This study investigates the efficacy of chemonucleolysis using RGE in the treatment of cervical disk hernias in a small sample of patients who had cervical diskogenic or radicular pain secondary to disk herniations. Results were satisfactory in 89.5% patients, with no adverse events recorded during the procedure or after. The use of RGE shows promising results and might be a feasible and safe alternative in the treatment of cervical disk hernias.