Endovascular approach to treatment of indirect carotico-cavernous fistulae

The purpose of the study was to assess the cure rate in patients with indirect carotico-cavernous fistula (CCF) treated by transvenous embolisation via the inferior petrosal sinus (IPS) pathway or the superior ophthalmic vein (SOV). Twelve fistulae in 11 patients were treated by transvenous embolisation, eight patients via the IPS and four fistulae in three patients via the SOV. Angiographic cure was defined as complete obliteration of the fistula and clinical cure as total resolution of signs and symptoms. Complete cure was achieved in eight patients with nine fistulae embolised transvenously. Five fistulae were approached via the IPS and four via the SOV. Our preferred method for treatment of indirect CCF is the transvenous route. The IPS approach is technically easier and has fewer potential risks than the SOV approach. However, if the IPS is not patent the SOV can provide good alternative access to the cavernous sinus.     

Transfemoral,transvenous embolisation of dural arteriovenous fistula involving the isolated transverse-sigmoid sinus from the contralateral side

Summary.  Background: A dural arteriovenous fistula (AVF) involving the transverse-sigmoid (T-S) sinus which is occluded at its proximal and distal ends i.e., an isolated sinus, runs the risk of haemorrhaging or causing serious neurological deficits as a result of its retrograde leptomeningeal venous drainage. While lesions of this type have not been considered to be treatable by percutaneous, transvenous embolisation, this paper challenges this view.  Case Presentation: Two middle-aged men with dural AVFs involving the isolated left T-S sinus presented with motor aphasia due to focal brain edema or haemorrhage. Under local anaesthesia, transfemoral, transvenous embolisation was performed with a microcatheter that was passed through the occluded proximal transverse sinus from the right (contralateral) side. The isolated sinus was then occluded with platinum coils. This embolisation resulted in angiographic and clinical cure of dural AVFs in both patients.  Interpretation: Transfemoral, transvenous embolisation is a therapeutic alternative for the treatment of dural AVFs involving the isolated T-S sinus. Embolisation obviates the need for craniotomy and general anaesthesia, which are required for the established modes of treatment, i.e., direct surgery or direct percutaneous sinus packing. Published online October 10, 2002 Correspondence: Masaki Komiyama, M.D., Department of Neurosurgery, Osaka City General Hospital, 2-13-22, Miyakojima-Hondori, Miyakojima, Osaka 534-0021 Japan.     

Embolisation of indirect carotid-cavernous sinus dural arterio-venous fistulae using the direct superior ophthalmic vein approach

Summary  Indirect carotid-cavernous sinus dural arterio-venous fistulae (cDAVF) can be treated by transarterial and/or transvenous embolisation. This study evaluated patients with cDAVF who underwent transvenous embolisation using the direct superior ophthalmic vein (SOV) approach. Between January 2004 and October 2006, eight cDAVF in seven patients were embolised using direct surgical exposure of the SOV when access to the cDAVF via transarterial or transfemoral venous routes was not feasible. Medical records and imaging studies were retrospectively reviewed. The seven patients consisted of four females and three males from 43 to 65-year-old (mean age, 54.4 years). Six cDAVF lesions were located on the left side and two on the right. All fistulae were successfully embolised and showed clinical improvement. One patient presented after treatment with transient venous congestion on the brain stem, which was relieved by osmotic diuretics and steroids. Direct surgical exposure of the SOV for transvenous embolisation of cDAVF can be effective if the facial vein, inferior petrosal sinus, and internal jugular vein are thrombosed. This approach is easy, safe, and effective when performed by a multidisciplinary team. Correspondence: Jae-Whan Lee, Assistant Professor, Department of Neurosurgery, Brain Research Institute, Yonsei University College of Medicine, 134 Shinchon-dong Seodaemun-gu, Seoul 120-752, Korea.     

Complications Associated with Transvenous Embolisation of Cavernous Dural Arteriovenous Fistula

Results are presented of transvenous embolisation, via either the inferior petrosal sinus (IPS) or the superior ophthalmic vein (SOV), for 19 patients with cavernous dural arteriovenous fistula with special emphasis on complications. In 17 patients (89%) there was complete angiographic elimination of the shunts and resolution of the symptoms. The remaining two patients also improved clinically, regardless of the minimal residual shunts. Complications included forehead dysaesthesia in one patient, blepharoptosis in two, and transient abducens nerve palsy in three. Injury of the supra-orbital nerve and levator muscle occurred in association with the exposure of the SOV in the patient with dysaesthesia of the forehead and in those with blepharoptosis, respectively. In two patients, abducens nerve palsy resulted from coil over-packing in the cavernous sinus and from dissection of the clival dura during guidewire penetration of the thrombosed IPS in one patient. We found that the complication rate decreased with time, because we became better with this procedure. We believe that transvenous embolisation is the best available treatment modality if one pays careful attention to avoid complications related to the procedure.     

Transvenous embolization for cavernous dural arteriovenous shunts: about the intracranial venous approach to the cavernous sinus

Recently, the first choice of therapy for cavernous dural arteriovenous shunts (CdAVS) is transvenous embolization. Usually the approach routes for cavernous sinus are the inferior petrosal sinus (IPS), the superior ophthalmic vein (SOV) in most cases and the superior petrosal sinus (SPS) in rare case. But, it is difficult for us to treat patients in whom there are no extracranial veins through which to approach the cavernous sinus, with transvenous embolization. We presented the case in which intracranial transvenous approach to the cavernous sinus and transvenous embolization were performed and in which we achieve good results. In this article, we presented a case with Barrow's type D CdAVS and cortical venous drainage. At first, transarterial embolization was performed to decrease the amount of venous drainage for the purpose of eliminate convulsions and consciousness disturbance. However, cortical venous drainage continued. Moreover bilateral dilated SOVs normalized and bilateral IPSs were not visible, so we decided that it was impossible to carry out the transvenous embolization via extracranial veins. Transvenous embolization to the left cavernous sinus via the intracranial ophthalmic vein between the superior ophthalmic fissure and the inferior ophthalmic fissure after craniotomy was performed. Then, the transvenous embolization to the right cavernous sinus was carried out through the right superficial middle cerebral vein after craniotomy. The results were good and chemosis and bilateral abducens palsy diminished immediately. Trans-intracranial venous embolization for CdVAS is a very useful therapy when no extracranial veins exist for transvenous embolization.     

Trans-arterial embolisation therapy of dural carotid–cavernous fistulae using low concentration n-butyl-cyanoacrylate

Background  Trans-venous embolisation has been accepted as the preferred treatment for dural carotid–cavernous fistulae (DCCF). However, such an approach is not always feasible. In this circumstance, trans-arterial embolisation with low concentration n-butyl-cyanoacrylate glue (NBCA) may be a feasible alternative. We report our results and experience of this method for DCCF. Materials and methods  Five patients with DCCF were treated by trans-arterial embolisation using low concentration NBCA by wedging the microcatheter into the main feeding artery. All five lesions were associated with venous drainage into the superior ophthalmic vein. The inferior petrosal sinus was patent in one patient and thrombosed in four. Additional venous drainage into the Sylvian vein and the superior petrosal sinus was observed in two patients. Findings  The definitive NBCA injection was performed via the branches of the middle meningeal artery in three patients and accessory meningeal artery as well as ascending pharyngeal artery in two patients. Four patients showed complete obliteration of the DCCF on the post-embolisation angiogram, and follow-up studies showed clinical cure or improvement and successful obliteration of the DCCF. One patient had a residual DCCF after the procedure, but showed complete obliteration and clinical cure at 5-month follow-up. Glue penetrated into the Sylvian vein in one patient during the procedure without sequelae. Two patients had transient worsening of ocular symptoms after the procedure. Conclusions  Trans-arterial embolisation with low concentration NBCA using a wedged microcatheter technique is still a safe and effective treatment for DCCF when the transvenous approach is not feasible. However, care must be taken to prevent inadvertent arterial and venous embolisation. An erratum to this article can be found at     

Transvenous Embolization for Vertebral Arteriovenous Fistula: Report of two Cases and Technical Notes

Summary  Background. Vertebral arteriovenous fistulas are relatively rare. Although the common treatment is transarterial embolization, it may be impossible to pass through the fistula (e.g. a microfistula created by a needle puncture). We report two patients with vertebral arteriovenous fistulas due to penetrating trauma who were successfully treated by transvenous embolization.  Method. We present 2 patients with vertebral arteriovenous fistulas. One patient is presented to demonstrate complications following attempted internal jugular cannulation and the other is presented to demonstrate complications after surgery for a jugular foramen neurinoma. Both patients manifested the sign of a severe bruit.  Findings. To identify the fistula point, simultaneous transarterial and transvenous angiography was performed. Using the transvenous approach, microcoils were applied to the fistula and the bruit completely disappeared. Interpretation. Transvenous embolization is a useful technique and a first-choice strategy to treat patients with the vertebral arteriovenous fistula due to penetrating trauma.     

Deterioration of Ocular Motor Dysfunction After Transvenous Embolization of Dural Arteriovenous Fistula Involving the Cavernous Sinus

Summary  We treated 9 patients with the dural arteriovenous fistula involving the cavernous sinus by transvenous embolization. Two patients experienced deterioration of oculo-motor dysfunction after transvenous embolization. We can speculate about two different kind of causes by which patients symptoms deteriorated according to the result of intrasinus pressure recorded during the embolization [1]: high intrasinus pressure caused by the obliteration of the drainage pathway resulted in cranial nerve palsy in one case [2]; implanted coils directly compressed the cranial nerve in another case. Fortunately our cases recovered, but some kind of preventative measures may be needed in similar cases.     

Difficult cannulation of the superior ophthalmic vein in the treatment of cavernous sinus dural arteriovenous fistula: two case reports

Retrograde cannulation of the superior ophthalmic vein (SOV) is an important route for embolization of cavernous sinus dural arteriovenous fistula (dAVF). We encountered two cases with significant difficulties with cannulation of the SOV. A 66-year-old woman and an 83-year-old woman were referred to our hospital for treatment of cavernous sinus dAVF. Unilateral chemosis and exophthalmos were seen in both patients. At first, transarterial embolization was performed to reduce the flow, then, transvenous embolization was employed for the treatment of cavernous sinus dAVF. The attempts to embolize through a transfemoral route failed owing to a thrombosed or compartmentalized cavernous sinus. Surgical exposure of the SOV and puncture with needle-cannula was tried. However, in both cases, unsuccessful cannulation resulted in uncontrollable bleeding and periorbital swelling. Finally, by using road-mapping SOV was punctured in the deeper part and the fistula was obliterated with detachable coils. Postoperative course was uneventful and their symptoms were improved. Although the SOV is a useful route for cavernous sinus dAVF embolization, the presence of narrowed or tortuous veins can preclude successful cannulation.     

Bypass – Surgery and Coil – Embolisation in the Treatment of Cerebral Giant Aneurysms

Summary  Objective. Operative clipping is the most effective method in the treatment of cerebral giant aneurysms. But about 50% of all giant aneurysms are treatable this way. We want to report about eight patients with giant cerebral aneurysms, which were in our opinion “unclippable” without causing ischaemia in depending brain areas.  Methods. We describe eight cases of giant aneurysms of the pericallosal artery (n=1), the middle cerebral artery (n=3), the basilar tip (n=3) and of the upper part of the basilar artery (n=1). One patient with an aneurysm of the pericallosal artery was treated with an extra-intracranial saphenous vein bypass saphenous bypass, in three cases of middle cerebral artery aneurysms an extra-intracranial bypass was also done combined with a resection of the aneurysm. The four patients suffering from an aneurysm of the basilar artery got an extra intracranial bypass too followed by an occlusion of the aneurysm with GD-Coils.  Results. There was no peri-operative mortality and no severe peri- or postoperative complication. The neurological symptoms of all patients were unchanged after the operation. An angiographic controll showed a complete obliteration of the aneurysm and a free running bypass in all cases.  Conclusion. Bypass surgery and combined bypass surgery and coil embolisation are effective methods in the treatment of giant cerebral aneurysms, which can not be treated by clipping alone.     

Migration of Pacemaker Lead Into the Spinal Venous Plexus: Case Report with Special Reference to Batson's Theory of Spinal Metastasis

Summary  Objective and Importance. Migration of a foreign material via venous routes into the spinal canal is a very rare incidence. We report the second case in which a foreign body has migrated into the spinal canal via the venous route.  Clinical Presentation. This 35-years-old man presented with sudden onset of severe low back pain and pain in the right leg four months after an unsuccessful attempt to remove a disconnected cardiac pacemaker lead via the femoral vein. Direct lumbar x-ray demonstrated the broken lead of the cardiac pacemaker at the entrance of the right L5 foramen which was also demonstrated by lumbar CT.  Surgical Intervention. After right L5 hemilaminotomy, the pacemaker lead was found in a vein of the anterior spinal venous plexus just beneath and lateral to the right L5 root. After dissecting it from the surrounding adipose tissue, the embolised pacemaker lead was taken out.  Conclusion. We present a case report and review of the literature on migration of foreign material into the spinal canal, factors effecting the flow directions in the spinal veins. This case may be the first evidence that proved Batson's theory of spinal metastases in man.     

Transarterial NBCA embolization with transvenous partial outflow obstruction for superior petrosal sinus dural arteriovenous fistula: a case report

We encountered a case of superior petrosal sinus dural arteriovenous fistula (SPS DAVF) which was treated by a combination of a transvenous and a transarterial approach after the failure of the transvenous approach alone. A 69-year-old man presented with a complaint of progressive left bulbar conjunctival conjestion, exophthalmos, and impaired vision. Cerebral angiography revealed a left SPS DAVF fed by the left middle meningeal artery, the meningeal branches of the left internal carotid artery and the left posterior meningeal artery. Venous drainage proceeded through the cavernous sinus (CS) toward the left superior ophthalmic vein (SOV). Transvenous embolization via the SOV was indicated because the left ipsilateral inferior petrosal sinus contributed to the normal venous return. However the microcatheter to the CS couldn't go through the tortuous SOV. Next a transarterial NBCA (n-butyl-cyanoacrylate) embolization of the affected sinuses was performed under arterial flow control with balloons and the partial coil embolization of the origin of the SOV. The coils in the SOV trapped NBCA and the sinuses were filled slowly with NBCA. The postoperative angiogram confirmed complete obliteration of the DAVF and the patient's ocular symptoms disappeared. DAVF is usually difficult to treat by transarterial embolization with NBCA because of its multiple feeders and high flow drainage. We should therefore carefully observe its structure and the blood flow change with 3D-DSA and the selective angiography while embolizing the DAVE.     

Transvenous occlusion of dural cavernous sinus fistulas through the thrombosed inferior petrosal sinus: report of four cases and review of the literature

BACKGROUND: The aim of this study is to describe the technique and results of the endovascular approach through the thrombosed inferior petrosal sinus (IPS) for occlusion of dural cavernous sinus fistulas (DCSFs). METHODS: In four patients presenting with clinically symptomatic DCSFs, the angiogram did not show opacification of the IPS, indicating that it neither drained the arteriovenous fistula nor the cerebral venous outflow. A large volume biplane phlebogram of the jugular bulb was obtained to identify a thrombosed remnant of the IPS. We were able to navigate small hydrophilic catheters and microguide wires through the thrombosed IPS into the ipsi- or contralateral CS. After reaching the fistula site the CS was packed with detachable platinum coils. RESULTS: We were able to reach the fistula site and to achieve a dense packing of coils within the arteriovenous shunting zone in all of the patients. The final angiogram showed subtotal or complete occlusion of the arteriovenous fistula. All four patients recovered completely and showed disappearance of the fistula on follow-up arteriograms. One patient developed a transient sixth nerve palsy. No complications related to the approach were observed. CONCLUSIONS: For endovascular treatment, transvenous occlusion of DCSFs via the IPS is a feasible approach, even when this sinus is partially or completely thrombosed. Gentle handling of recently available, improved hydrophilic microguide wires and microcatheters allows effective and safe catheter navigation into the CS. A phlebogram of the jugular bulb is very useful for identification of a thrombosed IPS.     

Multiple Pituitary Hormone Gradients from Cavernous Sinus Sampling in Patients with Cushing's Disease

Summary  Objective. Cavernous sinus sampling in patients with adrenocorticotropic-hormone (ACTH) secreting pituitary adenomas has been used to identify directly ACTH hypersecretion from the pituitary and to predict the lateralization of a microadenoma. In our previous series, cavernous sinus sampling provided a sufficient central/peripheral (c/p) ratio of ACTH and the correct laterality of the pituitary lesion in all microadenomas situated in the lateral wing. To clarify the diagnostic value of other anterior pituitary hormones in relation to ACTH gradients, we evaluated multiple pituitary hormone gradients between a cavernous sinus and a peripheral vein and between both cavernous sinuses in patients with Cushing's disease.  Methods. Cavernous sinus sampling was done in 11 patients with clinical and biochemical features of ACTH-dependent Cushing's syndrome. In 9, pituitary adenoma was detected during transsphenoidal surgery and histologically confirmed, while 2 others were suspected of having ectopic lesions. Serum ACTH, prolactin (PRL), thyroid stimulating hormone (TSH), growth hormone (GH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) from catheters in both cavernous sinuses and from a peripheral vein were measured. The c/p ratios of each hormone and the intercavernous gradients were evaluated.  Results. The c/p ratio of ACTH indicated the presense of pituitary lesions in all 9 patients with ACTH-secreting microadenomas. In addition, the intercavernous gradients of ACTH indicated the correct localization of microadenomas in all 6 patients with lateralized lesions. As for other hormones, the c/p ratios of GH, PRL, TSH and LH were significantly high in number 7, 6, 6 and 3 patients, respectively. In contrast, the significant step up of FSH was observed only in one patient. The intercavernous gradients of GH and PRL were significantly high in number 5 and 4 patients, respectively.  Conclusions. The intercavernous gradients of GH and PRL tend to indicate the lateralization of a microadenoma. The measurement of GH and PRL during cavernous sinus sampling may provide additional information, in the lateralization of ACTH-secreting microadenomas.     

Large sphenocavernous meningiomas: Is there still a role for the intradural approach via the pterional-transsylvian route?

Summary.  Background: Large-sized sphenocavernous meningiomas represent a surgical challenge. Although the role of skull base techniques with combined extra- and intradural steps has been recently emphasized, pure intradural resection tactics via the pterional route constitute the traditional microsurgical approach for resection of such tumours.  Method: We report the application of the pterional-transsylvian approach in 13 patients with sphenocavernous meningiomas. This series is unique because it includes only patients with tumours exceeding 5 cm in their greatest dimension.  Findings: A gross total resection was accomplished in 10 patients (77%). Eight patients had a good outcome, one had a persistent mild hemiparesis, and one died. No recurrences occurred in this group. Three patients (23%) had subtotal resections owing to invasion of the cavernous sinus in one instance and encasement of the middle cerebral artery in the others. Two had a good outcome and one died. In these patients minimal asymptomatic tumour progression was seen 3 and 6 years after surgery. The overall surgical outcome was good in 10 patients (77%), fair in one, and death in two.  Interpretation: In our experience, large sphenocavernous meningiomas may be operated on adopting pure intradural resection tactics via the pterional-transsylvian route with rates of gross total removal and surgical complications related to brain retraction or vascular manipulation comparable to those of extensive skull base approaches. The traditional intradural pterional transsylvian approach continues to have a place in the treatment of these lesions. Published online April 28, 2003 RID="*" ID="*"  This paper was supported in part by Grant “Piano B008 – P.R. 2” from M.U.R.S.T. and European Community.  Correspondence: Domenico d'Avella, M.D., Neurosurgical Clinic, Department of Neuroscience, Psychiatric and Anesthesiolgical Sciences, Policlinico Universitario, via Consolare Valeria 1, 98122 Messina, Italy.     

Craniocervical junction instability: instrumentation and fusion with titanium rods and sublaminar wires. Effectiveness and failures in personal experience

Summary.  Background: The aim of the study was to evaluate the effectiveness, pitfalls and failures of instrumentation and fusion with titanium wires and rods in 12 h patients with craniovertebral junction instability.  Methods: Among nine adult patients (mean age 48.11 years) with craniovertebral junction instability, four had basilar impression, three metastatic disease, one rheumatoid arthritis and one Down's syndrome. Three children (mean age 7.33 years) with genetic (Down's syndrome, 2 cases) and metabolic (mucopolisaccarydoses type IV, i.e. Morquio Syndrome, 1 case) disease were studied as well. Each patient underwent preoperative radiological evaluation by means of X-Ray, CT scan and MRI of the craniocervical region. Occipitocervical instrumentation with a titanium U-shaped wired rod was performed in each patient. Autologous bone fusion was performed in all but the two cancer patients, in whom polymethylmetacrylate was used. Postoperatively, all the patients used an external orthosis for 3–6 months. Post-operative X-Ray, CT and MRI were performed on each patient. The Frankel clinical scale was used to asses the outcome at follow-up which ranged from 1 to 10 years. At maximum follow up, there was either clinical improvement or stabilization recorded in all but one patient. This patient with basilar impression transiently worsened from grade D to C and a spinal cord lesion was already evident before the operation on MRI examination.  Interpretation: The effectiveness of surgical management of craniovertebral junction instability by instrumentation and fusion was demonstratedly in our experience. Nevertheless, the choice of the surgical technique should be made with caution when a spinal cord lesion is revealed by preoperative neuroimaging studies. Published online April 28, 2003 Acknowledgments  We thank MS. Ciara Harraher for editorial assistance.  Correspondence: Visocchi Massimiliano MD, Institute of Neurosurgery, Catholic University of “Sacred Heart”, Lgo. A. Gemelli, 8, 00168 Rome, Italy.     

Three-Dimensional Computed Tomographic Angiography in Four Patients with Dissecting Aneurysms of the Vertebrobasilar System

Summary ? Background. Recently, three-dimensional computed tomographic angiography (CTA) has been used for the diagnosis and treatment planning of cerebral aneurysm presenting with or without subarachnoid haemorrhage, but the diagnostic value of CTA has not been established. This study evaluated the usefulness of CTA in patients with dissecting aneurysms of the vertebrobasilar system.  Method. Four patients with acute dissecting aneurysms were examined by CTA, including 3 women and 1 man with a mean age of 60.5±8.5 years (range: 52–67 years). There were three patients with subarachnoid haemorrhage and one patient presenting with ischaemia. One patient underwent CTA twice and digital subtraction angiography (DSA) once, while one patient had both examinations three times. CTA was performed with a nonionic contrast medium (100 ml of iomeprol 350 mg I/ml) administered via an auto-injector into an antecubital vein at 1.5–1.7 ml/s. To reconstruct three-dimensional images, the volume rendering method was utilized.  Findings. All initial CTA studies were performed safely within 5 hours after onset. In patients with subarachnoid haemorrhage, all lesions were demonstrated by finding either the “pearl and string sign” or a “double shadow” on CTA. In the patient presenting with ischaemia, “pearl and string sign” and “double shadow” was shown after the second CTA, and follow-up CTA was able to demonstrate the change of the lesion morphology. All lesions had more irregular luminal surfaces than the non-lesional segments of the involved vessels.  Interpretation. CTA was safe in patients with acute vertebrobasilar dissection and demonstrated either the “pearl and string sign” or a “double shadow” which were commonly showed on DSA. An “irregular luminal surface sign” on CTA seems to be one of the characteristics of vertebrobasilar dissection.  The view shown by CTA is not less useful than that by DSA to diagnosis and treatment planning in the acute phase of vertebrobasilar dissection, and can also be employed to follow the changes of lesion morphology over time.     

Dural arteriovenous fistulas of the cavernous sinus with onset of intracerebral haemorrhage mimicking hypertensive putaminal hemorrhage

Summary We describe a patient with dural arteriovenous fistulas of the cavernous sinus (CS-dAVFs) who developed an intracerebral haemorrhage (ICH) mimicking hypertensive putaminal haemorrhage. Drainage into the superior ophthalmic vein (SOV) and inferior petrosal sinus (IPS) was not demonstrated on cerebral angiography, and only cortical venous reflux into the Sylvian vein was observed. In cases of venous drainage concentrated on the Sylvian vein, CS-dAVFs could indicate ICH with radiological appearance resembling putaminal haemorrhage.     

The Influence of Vascular Pressure and Angiographic Characteristics on Haemorrhage from Arteriovenous Malformations

Summary ? Background. The present study was designed to determine whether there is a physiological explanation for the predisposition of patients with certain angiographic characteristics to haemorrhage from cerebral arteriovenous malformations (AVMs).  Methods. Intra-operative measurement of feeding artery pressure (FAP) and intravascular pressures in the draining venous system [draining vein pressure (DVP) and cranial sinus pressure (SP)] were performed for 30 AVM cases using direct puncture of the vessels. The correlation between pressures and previously described angiographic characteristics predisposing to haemorrhage were evaluated.  Findings. Small nidus size and only one draining vein increased the risk of haemorrhage. FAP and DVP are both inversely related to the number of draining veins and the size of the AVMs. DVP was significantly higher in AVMs with haemorrhage (23.1±8.7 mmHg) than in those without (13.5±4.4), as was FAP (58.6±12.8 as opposed to 38.7±4.7) (p<0.05). Moreover, the difference between systemic blood pressure and the FAP with haemorrhagic AVMs (17.0±9.5 mmHg) was significantly lower than that in nonhaemorrhagic cases (33.7±5.5) (p<0.05). The pressure difference between the feeding artery and draining vein was not significant between the haemorrhagic and nonhaemorrhagic groups. There was no significant difference of SP between haemorrhagic and nonhaemorrhagic patients.  Interpretation. The present study suggests that a high DVP probably induced by high resistance in the venous drainage system, as well as a high FAP, may contribute to the development of haemorrhage from AVMs, and physiologically supports previous reports that small AVMs and AVMs with only one draining vein are susceptible to haemorrhage.     

Surgical Treatment of the Thrombosed Vein of Galen Aneurysm

Summary.  Objective and Importance: Vein of Galen aneurysm is a rare congenital anomaly of cerebral circulation and occurs mainly in newborns and children. The spontaneously thrombosed vein of Galen aneurysm is especially rare and an uncommonly reported event.  Clinical Presentation: Two patients with a spontaneously thrombosed vein of Galen aneurysm were operated on at our institute. CT and MRI demonstrated space-occupying lesions of the pineal region and two other masses in the posterior fossa in the second case. The first described case should be referred to as the true type of aneurysm. The vascular malformation, revealed in the second case should be referred to as the false type. In this case the vein of Galen was enlarged to a gigantic size due to the blood drainage from the arteriovenous malformation supplying it from the inferior posterior cerebellar artery.  Technique: Thrombosed aneurysmal sacs were resected totally by subtentorial supracerebellar and median suboccipital approaches.  Conclusion: The authors report two cases of successful surgical resection of a thrombosed vein of Galen aneurysm in children. Diagnostic features are considered and the informative value of magnetic resonance imaging is stressed. The principles of choosing the right approach and dissection techniques of thrombosed aneurysms of the vein of Galen are described. Published online September 2, 2002 Correspondence: Alexander N. Konovalov, Burdenko Neurosurgery Institute, 4 Tverskaya-Yamskaya st. 16, Moscow, Russia.