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Background: Practice patterns regarding the preoperative embolization of skull base tumors vary widely among institutions and are driven by surgeon preference and concerns about safety., Objective: We present a recent experience at our institution with a specific focus on procedural decision-making, embolization of vessels arising from the internal carotid circulation, and complication rates., Methods: During a 7.5-year period, 262 meningiomas were referred for embolization. of which 119 (45%) originated from the skull base. Tumors were categorized by location, feeding artery origin, and arteries embolized. Complication rates were reviewed., Results: Sixty-four of 119 patients with skull base tumors (54%) underwent embolization of at least 1 feeding artery. Feeding arteries arose from the external carotid artery (ECA) circulation in 26 (22%), the internal carotid artery (ICA) circulation in 30 (25%), a combination of ECA/ICA/Vert in 54 (45%), and had only pial supply in 10 (8%). In total, 15 of 85 (18%) ICA feeding vessels were embolized. This included 9 of 28 vessels from the meningohypopheseal trunk, 3 of 4 vessels from the anterior temporal artery, 1 of 35 vessels from the ophthalmic artery, 1 of 8 vessels directly from the ICA, and 1 of 5 vessels from the inferolateral trunk. Complete devascularization occurred in 6 of 64 patients; subtotal devascularization was seen in 58 of 64. The overall angiographic complication rate for all meningiomas embolized in the study period was 2.5% (5/199). None of the complications occurred in the skull base group., Conclusion: Preoperative embolization of skull base meningiomas and ICA feeding vessels can be done with low complication rates when intraprocedural decision-making favors complication avoidance over complete devascularization.

Objective: To describe a typical presentation of venous malformation within the masseter muscle, including physical findings and imaging, and to present the University of California, San Francisco's (UCSF) Vascular Anomalies and Birthmark Center's (VABC) experience with sclerotherapy for these lesions., Study Design: Case series with chart review., Setting: Tertiary care medical center., Subjects and Methods: Retrospective chart review of all patients presenting to the UCSF VABC over a 10-year period., Results: Twelve patients with isolated venous malformations of the masseter muscle were identified. All of these patients presented with pain and facial asymmetry that was more pronounced with jaw-clenching. All underwent magnetic resonance imaging demonstrating a T2 hyperintense homogenous mass contained within the masseter muscle. Eleven of 12 had evidence on imaging of phleboliths within the mass; 10 patients underwent sclerotherapy. All treated patients had initial improvement in symptoms and/or appearance. Seven of 10 have had sustained improvement at a mean follow-up of 28 months., Conclusion: Masseteric venous malformations have a typical clinical presentation and imaging characteristics that should allow clinicians to distinguish them from other abnormalities presenting in this area. Percutaneous sclerotherapy should be considered as a treatment option for these patients and can result in excellent outcomes., (Copyright © 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.)

Background and Purpose: Cerebral and cervical arterial abnormalities are the most common non-cutaneous anomaly in PHACE syndrome, but the location and type of arterial lesions that occur have not been systematically assessed in a large cohort. Our aim was to characterize the phenotypic spectrum of arteriopathy, assess the frequency with which different arteries are involved, and evaluate spatial relationships between arteriopathy, brain structural lesions, and hemangiomas in PHACE syndrome., Materials and Methods: Intracranial MRA and/or CTA images from 70 children and accompanying brain MR images in 59 patients with arteriopathy and PHACE syndrome were reviewed to identify the type and location of arterial lesions and brain abnormalities. Five categories of arteriopathy were identified and used for classification: dysgenesis, narrowing, nonvisualization, primitive embryonic carotid-vertebrobasilar connections, and anomalous arterial course or origin. Univariate logistic regression analyses were performed to test for associations between arteriopathy location, hemangiomas, and brain abnormalities., Results: By study design, all patients had arterial abnormalities, and 57% had >1 form of arteriopathy. Dysgenesis was the most common abnormality (56%), followed by anomalous course and/or origin (47%), narrowing (39%), and nonvisualization (20%). Primitive embryonic carotid-vertebrobasilar connections were present in 20% of children. Hemangiomas were ipsilateral to arteriopathy in all but 1 case. The frontotemporal and/or mandibular facial segments were involved in 97% of cases, but no other specific associations between arteriopathy location and hemangioma sites were detected. All cases with posterior fossa anomalies had either ICA anomalies or persistent embryonic carotid-basilar connections., Conclusions: The arteriopathy of PHACE syndrome commonly involves the ICA and its embryonic branches, ipsilateral to the cutaneous hemangioma, with dysgenesis and abnormal arterial course the most commonly noted abnormalities. Brain abnormalities are also typically ipsilateral.

Background and Purpose: CV following aneurysmal SAH is a significant cause of morbidity and mortality. We review our experiences using PTA and IA verapamil infusion for treating medically refractory cases., Materials and Methods: We performed a retrospective review of patients with SAH admitted from July 2003 to January 2008., Results: Of 546 patients admitted within 72 hours of symptom onset, 231 patients (42%) developed symptomatic CV and 189 patients (35%) required endovascular therapy. A total of 346 endovascular sessions were performed consisting of 1 single angioplasty, 286 IA verapamil infusions, and 59 combined treatments. PTA was performed on 151 vessel segments, and IA verapamil was infused in 720 vessel segments. IA verapamil doses ranged from 2.0 to 30.0 mg per vessel segment and from 3.0 to 55.0 mg per treatment session. Repeat treatments were necessary in 102 patients (54%) for persistent, recurrent, or worsening CV. There were 6 treatment-related complications, of which 2 resulted in clinical worsening. No deaths were attributable to endovascular therapy. At follow-up, 115 patients (61%) had a good outcome and 55 patients (29%) had a poor outcome. Sixteen patients died from causes related to SAH, while 3 died from other medical complications., Conclusions: Endovascular treatments are an integral part of managing patients with medically refractory CV. In our experience, PTA and IA verapamil are safe, with a low complication rate, but further studies are required to determine appropriate patient selection and treatment efficacy.

Background and Purpose: The natural history of PMAVFs, also known as type IV spinal cord AVFs, is incompletely understood. Both open surgical and endovascular approaches have been described as treatment modalities for this disease. The goal of this study was to evaluate the long-term outcome of patients with PMAVFs treated at a single tertiary care institution., Materials and Methods: We conducted a retrospective study of 32 patients with PMAVFs, evaluated between 1983 and 2009. Data were gathered by reviewing outpatient clinic notes, operative and radiologic reports, and spinal angiograms. The PMAVFs were categorized into 1 of 3 types based on the angiographic imaging criteria. Pretreatment and posttreatment ambulation and micturition symptoms were quantified by using the ALS., Results: Thirty patients underwent corrective procedures, 4 by embolization alone, 11 by surgery alone, and 15 with a combination of the 2. Twenty-eight patients underwent follow-up spinal angiography, with residual shunt noted in 6 patients. The mean follow-up period was 54 months (range, 1-228 months). Analysis of the ALS scores revealed that treatment of PMAVFs, independent of technique, resulted in significant improvement in ambulation but inconsistent changes in micturition. In addition, residual fistula at the time of the follow-up angiogram was associated with worsened neurologic status or lack of improvement. Outcome analysis based on fistula type showed dramatic improvement in ALS ambulation scores (62%) for type 3 fistulas, compared with types 1 and 2 (26% and 27%, respectively)., Conclusions: Significant improvement in ambulation but in not micturition was observed following treatment. Residual fistula on follow-up angiography was associated with progressive worsening or lack of improvement in neurologic function. Patients with type 3 fistulas were shown to benefit most from treatment, with marked improvement in posttreatment ambulation scores. As endovascular and surgical techniques continue to evolve, further studies are warranted.

A neonate with congestive heart failure at birth due to a nearly holohemispheric pial arteriovenous malformation is described. This occurred despite a normal second trimester prenatal sonogram. Successful treatment of heart failure was achieved by embolization alone. This case demonstrates that hemodynamically significant lesions may arise later or enlarge more rapidly in utero than previously thought.

Microcephalic osteodysplastic primordial dwarfism type II (MOPD II) is a rare genetic syndrome characterized by extremely small stature and microcephaly, and is associated in 25% of patients with intracranial aneurysms and moyamoya disease. Although aneurysmal subarachnoid hemorrhage and stroke are leading causes of morbidity and death in these patients, MOPD II is rarely examined in the neurosurgical literature. The authors report their experience with 3 patients who presented with MOPD II, which includes a patient with 8 aneurysms (the most aneurysms reported in the literature), and the first report of a patient with both moyamoya disease and multiple aneurysms. The poor natural history of these lesions indicates aggressive microsurgical and/or endovascular therapy. Microsurgery, whether for aneurysm clip placement or extracranial-intracranial bypass, is challenging due to tight surgical corridors and diminutive arteries in these patients, but is technically feasible and strongly indicated when multiple aneurysms must be treated or cerebral revascularization is needed.

Background and Purpose: Pediatric aneurysms are rare and, thus, relatively poorly understood as compared to those in adults. Our aim was to characterize the clinical, imaging, treatment, and outcome data of patients younger than 19 years diagnosed with intracranial aneurysms at a tertiary care institution., Materials and Methods: We performed a retrospective medical record review of pediatric patients examined at our university hospital between 1981 and 2008., Results: We evaluated 77 patients (mean age, 12 years; 40 female, 37 male) with 103 intracranial aneurysms. Patients presented with headache (45%), cranial neuropathies (16%), nausea/vomiting (15%), vision changes (13%), trauma (13%), seizure (4%), or sensory changes (3%). Subarachnoid hemorrhage occurred in 25 patients. Thirty-one fusiform aneurysms occurred in 25 patients. Forty-seven saccular aneurysms occurred in 35 patients. Twelve infectious aneurysms occurred in 6 patients. Fifteen traumatic aneurysms occurred in 12 patients. Fifty-nine patients underwent treatment of their aneurysms; 18 patients' conditions were managed conservatively. Nineteen patients underwent primary endovascular coiling, 1 patient had endovascular stent-assisted coiling, 11 patients underwent endovascular parent artery occlusion, 19 patients underwent surgical clipping, and 10 patients had aneurysms trapped and bypassed. Mortality was 1.3%. Morbidity included 8% infarction and 4% new-onset seizures. Six patients developed new aneurysms or had enlargement of untreated aneurysms., Conclusions: In our experience, intracranial aneurysms of childhood show a female predilection and predominantly saccular morphology. In neurovascular centers where microneurosurgical and endovascular options are available, most children with intracranial aneurysms can be successfully treated with low morbidity and mortality. Fusiform aneurysms require a combined microneurosurgical and endovascular approach more often than saccular aneurysms. The development of new aneurysms in pediatric patients during limited follow-up warrants further investigation.

Objective: Brain arteriovenous malformations (AVM) have high matrix metalloproteinase-9, interleukin-6, and myeloperoxidase (MPO) expression, and polymorphic variations in inflammatory genes are associated with an increased risk of hemorrhage. In this study, we characterized the presence of inflammatory cells in AVM lesional tissue specimens., Methods: Immunohistochemistry was used to identify and localize neutrophils (MPO as marker), macrophages/microglia (CD68 as marker), T lymphocytes (CD3 as marker), and B lymphocytes (CD20 as marker). Endothelial cell (EC) marker CD31 was used as an index to assess vascular mass (EC mass). Surgical specimens from 20 unruptured, nonembolized AVMs were examined; seven cortical samples from temporal lobectomy were used as controls. Positive signals for inflammatory cell markers were counted and analyzed by normalizing to the area of the tissue section and the amount of endothelial cells (cells/mm/EC mass pixels). Levels of MPO and matrix metalloproteinase 9 were determined by enzyme-linked immunosorbent assay., Results: Neutrophils and macrophages are all frequently identified in the vascular wall of AVM tissue. In contrast, T and B lymphocytes are rarely observed in AVM tissue. AVM tissue displayed more neutrophil and macrophage/microglia markers than epilepsy control tissue (MPO: 434 +/- 333 versus 5 +/- 4, P = 0.0001; CD68: 454 +/- 404 versus 4 +/- 2, P = 0.0001; cells/mm/EC mass pixels). In ex vivo studies, neutrophil quantity, MPO, and matrix metalloproteinase-9 levels were all colinear (R = 0.98-0.99)., Conclusion: Our study demonstrates that inflammatory cells are present in AVM tissue. Taken together with previous genetic and cytokine studies, these data are consistent with a novel view that inflammation is associated with AVM disease progression and rupture.

Objective: The disciplines of microneurosurgery and cranial base surgery have reached maturity, and technical advances in the surgical management of aneurysms are limited. Although most aneurysms can be clipped microsurgically or coiled endovascularly, a subset of patients may require a combined approach. A consecutive series of patients with aneurysms in one surgeon's cerebrovascular practice was reviewed retrospectively to analyze strategies for integrating microsurgical and endovascular techniques in the management of complex aneurysms., Methods: Between 1997 and 2001, 596 aneurysms in 491 patients were treated microsurgically by the senior author (MTL) at the University of California, San Francisco, and 77 of these patients (96 aneurysms) were managed with a multimodality approach comprising a total of eight different combinations: selective revascularization and aneurysm occlusion (n = 23), endovascular and surgical trapping (n = 1), clipping of the aneurysm after attempted or incomplete coiling (n = 22), coiling after attempted or incomplete clipping (n = 5), clipping of recurrent aneurysm after coiling (n = 6), coiling of recurrent aneurysm after clipping (n = 1), clipping and coiling of multiple remote aneurysms (n = 13), and coiling after previous surgery (n = 6)., Results: A total of 96 aneurysms were treated with combined therapy, of which 43% were large or giant in size and 34% had fusiform or dolichoectatic morphology. Complete angiographic obliteration was achieved in 91 aneurysms (95%). Overall, 66 patients (86%) had good outcomes (Glasgow Outcome Scale score of 4 or 5; mean follow-up, 9 mo). The treatment mortality rate was 9.1% (seven patients), and permanent treatment-associated neurological morbidity rate was 5.2% (four patients)., Conclusion: Evolving endovascular technologies need to be integrated into the microsurgical management of aneurysms. Multimodality approaches are best used with complex aneurysms in which conventional therapy with a single modality has failed. Revascularization remains a unique surgical contribution to the overall management of aneurysms with which current endovascular techniques cannot be used. Multimodality management should be considered an elegant addition to the therapeutic armamentarium that, through simplification and increased safety, improves the treatment of complex aneurysms beyond what is achievable by performing clipping or coiling alone.

Conservative surgical strategies are appropriate for most symptomatic hemangiomas causing cord compression without instability or deformity. Even so, complete intralesional spondylectomy following embolization of aggressive vertebral hemangiomas with circumferential vertebral involvement can be safely accomplished. Such a spondylectomy can also prevent recurrence of hemangiomas. Transarterial embolization without decompression is an effective treatment for painful intraosseous hemangiomas. Vertebroplasty is useful for improving pain symptoms, especially when vertebral body compression fracture has occurred in patients without neurological deficit, but is less effective in providing long-term pain relief.

Objective: The goals of this study were to characterize the clinical, radiological, treatment, and outcome data associated with patients diagnosed with spinal dural arteriovenous fistulae (SDAVFs) at a single tertiary care institution over a 20-year period., Methods: A 20-year retrospective study was undertaken at our university hospital. Patients with mixed intracranial and spinal dural fistulas were excluded. A literature review of articles reporting endovascular or combined treatment of SDAVFs was performed., Results: Between 1984 and 2005, our institution diagnosed and treated 63 patients (mean age, 62; 13 women, 50 men) with SDAVFs. The presenting symptoms were consistent with progressive myelopathy, and included lower extremity weakness (33 patients, 52%), parasthesias (19 patients, 30%), back pain (15 patients, 24%), and urinary symptoms (four patients, 6%). Thirty-nine patients underwent an initial endovascular embolization with 27 requiring only this first procedure for complete obliteration. On the other hand, 24 patients underwent an initial surgical procedure with 20 of them treated successfully with a single operation. Endovascular patients presented at mean age 62.3 years (standard deviation [SD], 10.6), were hospitalized for an average of 3.1 days (SD, 2.6), and were followed-up for 39 months (SD, 33). Surgical patients presented at mean age of 65.8 years (SD, 10.3), were hospitalized for 9.8 days (SD, 2.7), and were followed-up for 35 months (SD, 44). A significant improvement in Aminoff-Logue scores was found in both the endovascular and surgery groups (gait, P < 0.001; micturition, P = 0.005). The endovascular group had reduced hospitalization (P = 0.0001). No differences were found in the magnitude of clinical response to treatment., Conclusion: SDAVFs most commonly present with progressive myelopathy, yet often remain undiagnosed for months or years. Endovascular therapies and surgical therapies are associated with significantly improved symptoms once the definitive diagnosis of SDAVF is made.

Background and Purpose: Embolization of meningiomas has emerged as a preoperative adjuvant therapy that has proved effective in mitigating blood loss during surgical resection. Arterial supply to these tumors is typically identified by diffuse areas of parenchymal staining after selective x-ray angiograms. We investigate the benefits that selective injection of MR contrast may have in identifying vascular territories and determining the effects of embolization therapy., Materials and Methods: Selective intra-arterial (IA) injection of dilute MR contrast media was used to assess the vascular distribution territories of meningeal tumors before and after embolization therapy. Regions of the tumor that experienced loss of signal intensity after localized contrast injections into the external and common carotid as well as vertebral arteries were used to quantify the specific vessel's volume of distribution. Assessments were made before and after embolization to reveal changes in the vascular supply of the tumor. MR findings were compared with radiographic evaluation of tumor vascular supply on the basis of conventional x-ray angiography., Results: MR proved to be an excellent means to assess tissue fed by selected arteries and clearly demonstrated the treated and untreated portions of the neoplasm after therapy. In some instances, MR revealed postembolization residual enhancement of the tumor that was difficult to appreciate on x-ray angiograms. Very low contrast dose was necessary, which made repeated assessment during therapy practical., Conclusion: MR perfusion imaging with selective IA injection of dilute contrast can reveal the distribution territory of vessels. Changes in tumor vasculature could be detected after embolization, which reveal the volumetric fraction of the tumor affected by the therapy.

Purpose: Intracranial aneurysm (IA) growth is associated with increased morbidity. We sought to establish a quantitative computational method based on contrast-enhanced MR angiography (CE-MRA) for estimating aneurysmal volume changes over time., Materials and Methods: Computational volume calculations were tested against a distensible phantom. Untreated patients with IA were followed longitudinally with annual MRI. Maximal linear dimensions along the longitudinal axis and two transverse axes were determined by visual review of maximum intensity projection (MIP) data, and aneurysm volume was approximated as (length x width x height)/2. Averages of the visual approximations were compared to the lumenal volume as determined with a computational algorithm using the MRI data., Results: MRI-based measurements accurately represented volume changes in the phantom (R2 = 0.97, Y = 1.06x + 271 CM3). In the clinical study there were a total of 11 intervals of one-year follow-up in six patients (mean +/- SD, age = 53 +/- 20 years). The raw one-year growth using the computational volume was 9% +/- 17%. The corresponding value for the averaged measurement of the reviewers was 8% +/- 14%. Neither the mean values nor the SDs were different (P = .51)., Conclusion: MRI-based measurement of aneurysm volume appears feasible for longitudinal studies of aneurysm natural history., (Copyright 2007 Wiley-Liss, Inc.)

Objective: Diffuse arteriovenous malformations (AVM) have non-compact niduses, irregular margins, and intervening brain parenchyma. Deep perforating arteries often contribute to the ragged border of these diffuse AVMs. We hypothesized that diffuseness and deep perforator supply increase the difficulties and risks associated with microsurgical AVM resection., Methods: Diffuseness was quantified using computer-generated outlines of AVMs on angiograms, contour plots with varying image intensities, and calculations of nidus area-intensity profiles. Diffuse AVMs had nonlinear area-intensity profiles with high transition intensities ([I*] greater than 0.5). A consecutive series of 304 patients who were treated with microsurgical AVM resection over a period of 7.8 years was analyzed, along with quantification of diffuseness in a subset of 103 consecutive patients. Neurological outcomes were assessed by using the Modified Rankin Scale, and logistic regression analysis was used to identify predictors of deterioration and poor outcome at late follow-up evaluation., Results: Diffuse niduses were observed in 25% of patients, and 18% of patients had deep perforating artery supply. Patients with compact AVMs were more likely to have good outcomes or overall improvement (88 and 87%, respectively) than patients with diffuse AVMs (65 and 54%, respectively) (P = 0.008 and P < 0.001, respectively). Similarly, absence of deep perforator supply was associated with good outcomes or improvement in 85 and 78% of patients, respectively, compared with 63 and 64% of patients, respectively, in patients with deep perforator supply (P < 0.001 and P = 0.028, respectively). By logistic regression analysis, diffuseness and deep perforator supply were both associated with significant increases in surgical risk., Conclusion: Diffuseness and deep perforating artery supply are subtle features of an AVM that predict worse outcomes after microsurgical resection. Diffuseness makes surgical planes more difficult to determine and follow, whereas deep perforators are friable, poorly visualized, and located in eloquent white matter tracts. The Spetzler-Martin grading scale does not directly account for these two features; however, they should be considered carefully when making treatment recommendations to patients with AVMs.

Summary: We report 3 patients with previously undiagnosed spinal dural arteriovenous fistulas (SDAVFs), who developed acute paraparesis following lumbar epidural steroid injection. MR imaging demonstrated spinal cord T2 hyperintensity, edema and/or enhancement of the conus, and intradural enlarged vascular flow voids. Spinal angiography confirmed SDAVFs arising from pedicles remote from the sites of the epidural steroid injection. Fistulas were eliminated with either endovascular or combination endovascular and open surgical approaches, with subsequent partial resolution of paraparesis.

Objective: We analyzed the outcome of patients with symptomatic vertebral hemangiomas treated at University of California, San Francisco, over a 20 year period. Treatment included transarterial embolization, embolization followed by surgical decompression or vertebral reconstruction with arthrodesis, and percutaneous vertebroplasty alone., Methods: All medical, surgical, and radiological records were reviewed retrospectively. All patients underwent follow-up neurological examination and evaluation of back pain., Results: Sixteen patients diagnosed with symptomatic vertebral hemangiomas causing pain or neurological deficit were treated at University of California, San Francisco, between 1984 and 2004. Mean follow-up was 81 months. Seven of nine patients undergoing surgical decompression and tumor resection reported pain relief and demonstrated improvement in neurological deficit when present. Two patients had recurrent myelopathy: one was successfully treated with a second decompressive surgery, whereas the second underwent a staged vertebrectomy. All three patients undergoing vertebrectomy had cord compression from extraosseous tumor growth. Preoperative embolization reduced expected intraoperative blood loss in four patients. Three of four patients who underwent transarterial embolization alone experienced resolution of back pain. Two of four patients treated with vertebroplasty had long-term pain relief., Conclusion: Transarterial embolization followed by laminectomy is a safe and effective procedure for the treatment of cord compression by vertebral hemangioma causing stenosis without instability or deformity. Vertebrectomy preceded by embolization and followed by reconstruction can be used to treat cord compression from extraosseous tumor extension. Transarterial embolization without decompression is an effective treatment for painful intraosseous hemangiomas. Vertebroplasty is useful for improving pain symptoms, especially when vertebral body compression fracture has occurred in patients without neurological deficit, but is less effective in providing long-term pain relief.

Objective and Importance: Intraorbital arteriovenous fistulas (AVF) of the ophthalmic veins are an extremely rare phenomenon. This article describes two such cases treated solely by transvenous occlusion and not hitherto described in the literature., Methods and Results: Two women, aged 51 and 63 years old, presented with proptosis and chemosis mimicking a carotid-cavernous fistula. In both cases, cerebral angiography revealed an intraorbital dural AVF of the superior and inferior ophthalmic vein, respectively. Both patients underwent transvenous ablation of the dural AVF retrograde via the facial vein and subsequently had complete resolution of the presenting symptoms., Conclusion: Ophthalmic vein fistulas are a rare form of AVF with presenting symptoms mimicking those of carotid cavernous fistulae. This report describes two cases of ophthalmic vein fistulas successfully treated and angiographically obliterated via transvenous embolization with resolution of the patient's presenting symptoms.

Objective: Despite its quantitative definitions, the Spetzler-Martin grading scale for brain arteriovenous malformations (AVMs) is subject to interobserver variability, particularly when observers differ in their subspecialties. Interobserver variability between neuroradiologist and neurosurgeon grading was analyzed in a large AVM series to determine its extent, causes, and clinical implications., Methods: In a consecutive surgical series of 224 AVM patients, Spetzler-Martin grades were assigned independently by a neuroradiologist and a neurosurgeon. Interobserver agreement was measured with a Cohen kappa analysis and the Wilcoxon signed-rank test., Results: Disagreement in grades occurred in 62 (27.7%) patients. By kappa analysis, agreement was highest for venous drainage pattern (kappa = 0.90), intermediate for eloquence (kappa = 0.71), and lowest for size (kappa = 0.67), with substantial agreement on overall grade (kappa = 0.61). By Wilcoxon signed-rank test, size scores and AVM grades were significantly different. Causes of interobserver variability in grading included diffuse nidus, differences in angiographic versus surgical borders, paradoxical venous drainage, and the ambiguity of eloquence. Interobserver variability affected outcome data but did not diminish the predictive value of the Spetzler-Martin scale., Conclusion: The Spetzler-Martin grading system can be applied reliably to most AVMs with good agreement between observers, but some unusual AVMs expose the system's imprecision and subjectivity. Interobserver variability can affect reporting of results, surgical risk assessment, and patient selection. Undergrading may encourage borderline surgical candidates to choose surgery and obtain results below their expectations.

Background and Purpose: A new neurovascular microstent, the Cordis Enterprise stent, composed of nitinol, with a closed cell design, was specifically developed for the treatment of wide-necked intracranial cerebral aneurysms. The purpose of this study was to evaluate the safety, feasibility, and initial clinical results of using this device in patients., Methods: In clinical evaluation, five patients ranging in age from 54 to 71 years were electively treated. The smallest aneurysm measured 3.3 x 2.9 mm, and the largest aneurysm measured 10.6 x 8.5 mm (neck and height measurements)., Results: All five cases (100%) were technically successful without complications. In each case, the stent was accurately placed in the desired location, immediately followed by coil embolization to the desired degree of occlusion with a satisfactory result. The poststent and coil-occlusion angiogram demonstrated excellent blood flow across the stent, with satisfactory positioning of the coils within the aneurysm in all cases (100%). No patient suffered any clinical or neurologic complications, and all were discharged 1-3 days postprocedure, in stable condition with no new neurologic deficits., Conclusion: In early clinical studies, the Cordis Enterprise stent performed well. The stent was able to be well visualized, deployed easily, could be repositioned if needed, and was accurately placed without technical difficulties. The closed cell design allowed all coils to be placed within the aneurysm and remain outside the flow of the parent artery. No periprocedural complications were encountered.

Eighteen patients underwent stenting for symptomatic basilar artery stenosis. There were three major periprocedural complications (16.7%) without fatality. At a mean 26.7 +/- 12.1-month follow-up, 15 patients (83.3%) had an excellent long-term outcome. Only one patient (5.6%) had moderate disability from recurrent stroke, and two patients died of medical illness at 30 and 36 months after stenting. In this uncontrolled study, stenting appeared to be effective in reducing stroke risk and death and worthy of further scrupulous trial.

Background and Purpose: Patients undergoing stent placement as treatment for severe stenosis of the internal carotid artery (ICA) were assessed with MR imaging in a combined MR-radiographic (XMR) angiography suite. MR imaging was performed before and immediately following conventional radiography-guided stent placement. Changes in MR imaging measurable properties, including flow and perfusion, resulting from stent placement were evaluated., Patients and Techniques: MR imaging analysis was performed for 12 patients with >70% stenosis of the ICA before and after conventional radiography-guided deployment of a carotid stent. MR imaging acquisitions included angiography, quantitative flow analysis, perfusion, diffusion, and turbo-fluid-attenuated inversion recovery (FLAIR). These acquisitions were all performed immediately before and following stent placement by using conventional techniques., Results: MR angiography proved sufficient for identifying the target lesion and permitting targeted flow analysis. MR flow analysis demonstrated a marked increase in flow in the treated carotid artery (+2.2 +/- 1.2 mL/s) and little change in other extracranial arteries. MR perfusion imaging showed no significant differences in relative cerebral blood volume between hemispheres before or after treatment, but there was a modest decrease in mean transit time and time to peak evident in the treated hemisphere after stent placement. Diffusion imaging did not demonstrate any ischemic foci resulting from carotid stent treatment. Hyperintensity of the CSF was noted on turbo-FLAIR acquisitions in the ipsilateral hemisphere following stent placement in 75% of patients., Conclusion: MR imaging reliably reflects the state of the carotid artery and provides a means of monitoring and quantifying the effects of revascularization.

Objective: Subarachnoid hemorrhage (SAH) is associated with cardiac injury and dysfunction. Whether aneurysm clipping versus coiling has a differential effect on the risk of troponin release and left ventricular (LV) dysfunction after SAH is unknown. It is hypothesized that aneurysm treatment does not affect the risk of developing cardiac injury and dysfunction., Methods: The study included 172 consecutive SAH patients who underwent clipping (n = 109) or coiling (n = 63) aneurysm therapy. Hemodynamic data were collected, cardiac troponin I was measured, and echocardiography was performed on the 1st, 3rd, and 6th days after enrollment. A cardiac troponin I measurement of more than 1.0 microg/L was considered abnormal. For each echocardiographic examination, a blinded observer measured LV ejection fraction (abnormal if <50%) and quantified LV regional wall motion abnormalities. The incidence of cardiac outcomes in the treatment groups was compared using odds ratios (ORs)., Results: The coiled patients were older than the clipped patients (mean age, 59 +/- 13 yr versus 53 +/- 12 yr; t test, P < 0.001) and were more likely to have posterior aneurysms (33% versus 18%; chi(2) test, P = 0.019). There were no significant between-group differences in the risk of cardiac troponin I release (coil 21% versus clip 19%; OR = 0.89, P = 0.789), regional wall motion abnormalities (33% versus 28%; OR = 0.76, P = 0.422), or LV ejection fraction lower than 50% (16% versus 17%; OR = 1.06, P = 0.892). No patient died of cardiac causes (heart failure, myocardial infarction, or arrhythmia)., Conclusion: Surgical and endovascular aneurysm therapies were associated with similar risks of cardiac injury and dysfunction after SAH. The presence of neurocardiogenic injury should not affect aneurysm treatment decisions.

Background and Purpose: Papaverine is used to vasodilate cerebral arteries undergoing vasospasm from subarachnoid hemorrhage. However, papaverine inhibits cellular respiration in vitro and could cause neurotoxicity in humans., Methods: We studied 5 consecutive patients with cerebral vasospasm who were treated with intra-arterial papaverine preserved with chlorobutanol and imaged with MRI fluid-attenuated inversion recovery and diffusion-weighted imaging after treatment. One patient had histological analysis of the brain at autopsy., Results: All 5 patients exhibited marked neurological decline immediately after treatment, and this was sustained through hospital discharge. In all cases, MRI images showed selective gray matter-only signal changes within the vascular territory treated with papaverine. Histological analysis of 1 case brought to autopsy showed selective injury to islands of neurons with relative sparing of white matter., Conclusions: Intra-arterial delivery of papaverine preserved with chlorobutanol into vasospastic anterior cerebral arteries may result in marked neurological deterioration with selective gray matter changes on MRI imaging. This effect is consistent with a permanent toxic effect to human brain. It is unclear whether this toxicity is caused by papaverine or chlorobutanol, and its use in the treatment of cerebral vasospasm should be reserved for cases without alternatives.

Objective: Central venous sampling (CVS) is used frequently in the evaluation of ACTH-dependent Cushing's syndrome. However, several controversies exist including the diagnostic accuracy, the sampling site of choice (cavernous sinus vs. inferior petrosal sinus) and the use of lateralization data in tumour localization. We have analysed our experience with CVS to address these controversies., Design: We retrospectively reviewed CVS data in patients with ACTH-dependent Cushing's syndrome, in whom cavernous sinus sampling (CSS), inferior petrosal sinus sampling (IPSS) and IPSS after administration of ovine corticotrophin releasing hormone (oCRH) were performed., Patients: Data on 95 patients were analysed, including 79 patients with suspected Cushing's disease (CD) and 16 patients with suspected ectopic ACTH syndrome (EAS)., Results: For the differential diagnosis of ACTH-dependent Cushing's syndrome, the diagnostic accuracy of IPSS after oCRH stimulation was 97% compared to 86% for CSS. While no single sampling site was perfect in diagnostic accuracy, sampling both CS and IPS achieved a combined diagnostic accuracy of 100%. Lateralization data predicted tumour location in 62-68% of the patients with various central venous drainage patterns and in 77-80% of the patients with symmetrical drainage. CSS was not significantly superior to IPSS in tumour lateralization. In patients with suspected CD based on CVS and in whom an adenoma was not found on magnetic resonance imaging (MRI) and not located by the surgeon intraoperatively, hemihypophysectomy based on lateralization data was successful in only 10 of the 18 patients (56%) with various central venous drainage patterns and in 5 of 10 patients with symmetrical drainage., Conclusion: CVS is a powerful method for differentiating CD from the EAS. CSS without oCRH was not superior to IPSS after oCRH stimulation; however, we achieved a 100% diagnostic accuracy if at least two sites were sampled. Tumour localization by CVS did not accurately predict the tumour site at surgery and should not be used to guide surgical resection.

Background: The goal of this study was to examine safety and efficacy of transarterial embolization for the treatment of idiopathic posterior epistaxis., Methods: A retrospective chart review was conducted to characterize the underlying conditions of eighty-one consecutive patients for whom complete records were available presenting with posterior epistaxis, the associated risk factors for patients with idiopathic posterior epistaxis, and the success rate of embolization in this patient population., Results: One hundred consecutive patients undergoing embolization for epistaxis were identified and 81 patients were included in the analysis. Nineteen patients did not have sufficient and retrievable medical records to be included in the study. Idiopathic posterior epistaxis was the most common underlying etiology of patients with refractory posterior epistaxis (34%). Hypertension, vascular disease, and diabetes were frequently detected comorbid diseases. Patients were equally as likely to be hypertensive as normotensive at the time of presentation (45 and 55%, respectively). Most patients (83%) had failed at least one prior treatment modality. Few patients had a recurrence of epistaxis within 72 hours (three patients [12%]) or had an adverse effect associated with embolization (three patients [12%])., Conclusion: Embolization for the treatment of posterior epistaxis is a safe and effective treatment modality.

Objective: We hypothesized that coexisting extranidal arterial aneurysms (EAs) would be associated with an increased risk of incident intracranial hemorrhage (ICH) from brain arteriovenous malformation (BAVM) rupture., Methods: To determine the presence of EAs and compare the sources and locations of ICH, we retrospectively reviewed the computed tomographic, magnetic resonance imaging, and angiographic studies of patients who presented between 1990 and 1999. EAs were defined as saccular luminal dilations of the parent feeding vessels that were proximally flow-related (i.e., at the circle of Willis), distally flow-related (i.e., distal to the circle of Willis), and unrelated (i.e., in circulation distant from the BAVM)., Results: Of 314 BAVM patients, 138 (44%) presented with ICH. In the ICH group, 22 patients (16%) had aneurysmal ICH, 100 (72%) had BAVM ICH, and 16 (12%) had ICH from an indeterminate source. There were 61 patients with 1 or more EAs (29 patients with 42 flow-related proximal aneurysms, 39 patients with 48 flow-related distal aneurysms, and 10 patients with 20 unrelated aneurysms). Multivariate regression analysis revealed that ICH patients were more likely than non-ICH patients to have a coexisting EA (35 versus 13%; odds ratio = 3.9; 95% confidence interval, 2.1-7.5; P < 0.001), but this effect was not present when only BAVM-related ICH was considered (odds ratio = 0.3; 95% confidence interval, 0.1-1.0; P = 0.052). Other independent predictors of ICH included small AVM size (<3 cm), exclusively deep venous drainage, and the presence of an intranidal aneurysm., Conclusion: Clinical presentation with ICH was associated with EA aneurysms, but the association was due to aneurysmal rather than BAVM rupture, suggesting that EAs and the BAVM ICH risks may be considered as separate entities in future studies.

We report a case of fatal subarachnoid hemorrhage from nontraumatic rupture of an aneurysm at the basilar terminus in which both computed tomography angiography and conventional angiography showed evidence of active bleeding. The time period from initial ictus to CT angiography was 30-50 minutes and to conventional angiography was 120-140 minutes. This case illustrates that aneurysmal bleeding is not necessarily as brief as a few seconds and can last up to 30 to 50 minutes and perhaps longer. Continued bleeding from an intracranial aneurysm is a rare event that can be recognized using computed tomography angiography and likely indicates a poor prognosis.

Stroke is a common cause of death and disability in industrialized nations. Technical advances and the increased availability of noninvasive brain imaging techniques have permitted precise and early diagnosis of acute cerebral ischemia. This has made emergent thrombolytic therapy for rapid restoration of cerebral perfusion increasingly possible. Herein, the authors present a review of the clinical trials investigating acute stroke treatment with intraarterial thrombolysis.

Objective: The most common location for dural arteriovenous fistulae (AVFs) is the transverse/sigmoid sinus. We describe our prospective analysis of data for 10 patients with recipient fistulae parallel to the transverse/sigmoid sinus. Recognition of this entity allows embolization of the fistula with preservation of the parent sinus. This report reviews the presentation and angiographic characteristics of the "parallel venous channel" and the treatment results for this series of patients., Methods: Between 1995 and June 2002, at the medical center of the University of California, San Francisco, we identified 10 patients with a parallel venous channel as the recipient pouch for all arterial input into a transverse/sigmoid sinus AVF. The clinical presentations, angiographic features, endovascular treatments, and outcomes are described. Angiographic follow-up monitoring was performed for 1 to 6 years for all patients with cortical venous drainage (5 of 10 patients). Clinical follow-up periods ranged from 1 to 7 years., Results: All patients presented with pulsatile tinnitus disruptive to sleep. Other symptoms included severe headaches, papilledema and visual disturbances, hemiparesis, and mastoid pain. All 10 parallel venous channels communicated with the transverse or sigmoid sinus. Cortical venous drainage was present in 50% of cases. Endovascular ablative procedures, using either coils or ethanol, were performed for all patients. The parallel venous channel was successfully embolized, with preservation of the transverse/sigmoid sinus, for all 10 patients. There were no major complications. All patients experienced resolution of their symptoms, with no recurrence., Conclusion: The existence of a parallel venous channel as the recipient pouch for all arterial inflow in a series of 10 transverse/sigmoid sinus AVFs is described. Endovascular obliteration of the parallel channel, with preservation of the parent sinus, was successfully performed for all 10 patients. Recognition of the parallel venous channel is clinically important for the treatment of transverse/sigmoid AVFs.

Interventional neuroradiology is a less invasive modality than open neurosurgery for the treatment of a wide range of neurovascular disorders. Refinements in technique and improvements in the design of microcatheters, guide wires, and embolic materials have yielded superior clinical outcomes and provided an impetus to treat more of these lesions endovascularly rather than surgically. Endovascular therapy is the standard of care for direct and indirect carotid artery cavernous sinus fistulas and may also be curative for dural arteriovenous fistulas (AVFs) in other locations. The authors provide review of the clinical features, pathophysiology, and management of intracranial AVFs focusing on contemporary endovascular treatment options.

The field of interventional neuroradiology has experienced remarkable technological developments in microcatheters and embolic materials during the past two decades. The realm of meningioma therapy has benefited handsomely from the combination of these technical improvements and the knowledge of experienced practitioners in this field. Transarterial embolization has become a standard procedure in the preoperative management of meningiomas. The authors describe the indications, pretreatment evaluation, techniques, and outcomes when preoperative angiography and embolization are performed in the treatment of these tumors.

Objective: To determine the usefulness of endovascular embolization for treatment of dural arteriovenous fistulae of the superior petrosal sinus., Methods: We performed a retrospective review of 18 patients treated during a 16-year period. Transarterial and/or transvenous embolizations were performed as a preoperative adjunct or definitive therapy. Clinical follow-up status was supplemented by telephone interviews to determine Glasgow Outcome Scale scores., Results: Fourteen patients (78%) were treated with a combination of endovascular therapy and open surgery, and 4 were treated by embolization alone (22%). Angiographic cure was achieved in all patients (100%). Thirty-day morbidity and mortality were 11 and 0%, respectively. The mean follow-up period was 5.4 years. At the latest follow-up examination, all patients had returned to independent clinical status (Glasgow Outcome Scale scores of 1 or 2)., Conclusion: Endovascular treatment of dural arteriovenous fistulae of the superior petrosal sinus can result in cure when access to the site of the fistula can be achieved. Preoperative embolization is a safe and effective adjunct to minimize bleeding during open neurosurgery.

We present a case of Guglielmi detachable coil extraction into a microcatheter after coil detachment during embolization of a superior hypophyseal artery aneurysm; extraction was a result of the suction generated during pusher-wire withdrawal. Experimental simulations using many coil and microcatheter combinations were used to identify factors that contribute to the likelihood of this phenomenon.

Background and Purpose: Excessive degradation of the vascular matrix by matrix metalloproteinases (MMPs) can lead to structural instability of vessels. In this study we examined the expression of MMPs and tissue inhibitors of metalloproteinases (TIMPs) in brain arteriovenous malformations (BAVMs)., Methods: We performed gelatin zymography for MMPs and Western blot for MMP-9, MMP-2, TIMP-1, TIMP-2, TIMP-3, and TIMP-4. MMP-9 expression was localized by immunohistochemistry., Results: We analyzed 37 BAVM specimens and 9 control brain specimens from epilepsy surgery. Thirty-two BAVM patients had embolization treatment before resection. Eighteen BAVM patients had a history of hemorrhage from BAVMs. Neither MMP-2 nor TIMP-2 was detected in BAVMs or control brain specimens. Compared with control brain samples, BAVM samples had higher levels of total MMP-9, active MMP-9, pro-MMP-9, TIMP-1, and TIMP-3. TIMP-4 levels were higher in the control brain than in BAVM specimens. MMP-9 was localized to the endothelial cell/peri-endothelial cell layer and infiltrating neutrophils of BAVMs. BAVMs with venous stenosis >or=50% had higher expression of MMP-9 than BAVMs with venous stenosis <50%. There was no apparent association between total MMP-9, pro-MMP-9, or active MMP-9 levels and (1) feeding artery pressure, (2) pattern of draining vein (exclusively deep venous drainage versus any superficial drainage), and (3) BAVM size., Conclusions: We found increased levels of MMP-9 and TIMPs in BAVMs. Abnormal balance of MMP-9 and TIMPs may contribute to vascular instability of BAVMs.

Objective: The disciplines of microneurosurgery and cranial base surgery have reached maturity, and technical advances in the surgical management of aneurysms are limited. Although most aneurysms can be clipped microsurgically or coiled endovascularly, a subset of patients may require a combined approach. A consecutive series of patients with aneurysms in one surgeon's cerebrovascular practice was reviewed retrospectively to analyze strategies for integrating microsurgical and endovascular techniques in the management of complex aneurysms., Methods: Between 1997 and 2001, 596 aneurysms in 491 patients were treated microsurgically by the senior author (MTL) at the University of California, San Francisco, and 77 of these patients (96 aneurysms) were managed with a multimodality approach comprising a total of eight different combinations: selective revascularization and aneurysm occlusion (n = 23), endovascular and surgical trapping (n = 1), clipping of the aneurysm after attempted or incomplete coiling (n = 22), coiling after attempted or incomplete clipping (n = 5), clipping of recurrent aneurysm after coiling (n = 6), coiling of recurrent aneurysm after clipping (n = 1), clipping and coiling of multiple remote aneurysms (n = 13), and coiling after previous surgery (n = 6)., Results: A total of 96 aneurysms were treated with combined therapy, of which 43% were large or giant in size and 34% had fusiform or dolichoectatic morphology. Complete angiographic obliteration was achieved in 91 aneurysms (95%). Overall, 66 patients (86%) had good outcomes (Glasgow Outcome Scale score of 4 or 5; mean follow-up, 9 mo). The treatment mortality rate was 9.1% (seven patients), and permanent treatment-associated neurological morbidity rate was 5.2% (four patients)., Conclusion: Evolving endovascular technologies need to be integrated into the microsurgical management of aneurysms. Multimodality approaches are best used with complex aneurysms in which conventional therapy with a single modality has failed. Revascularization remains a unique surgical contribution to the overall management of aneurysms with which current endovascular techniques cannot be used. Multimodality management should be considered an elegant addition to the therapeutic armamentarium that, through simplification and increased safety, improves the treatment of complex aneurysms beyond what is achievable by performing clipping or coiling alone.

Background: Preoperative noninvasive localization studies of the neck and mediastinum are beneficial before reoperation. However, the role of selective venous sampling (SVS) for parathyroid hormone (PTH) in reoperative parathyroid surgery has never been clearly defined. The purpose of this study was to evaluate the accuracy of SVS when applied selectively to the subset of patients with indeterminate noninvasive localization studies., Methods: Between January 1990 and December 2001, 64 of 235 (27%) patients with persistent or recurrent hyperparathyroidism were considered candidates for SVS in addition to noninvasive localization studies. Accuracy of SVS for PTH was retrospectively evaluated., Results: Successful surgical treatment was achieved in 86% of these patients. SVS for PTH yielded true-positive results in 75% of patients and was not useful for the surgeon in 17% (completely false-positive in 12% and indeterminate in 5%). In 2% of patients, SVS identified successfully 1 gland but failed to locate another abnormal gland. In 6% of patients, the location of the abnormal parathyroid tissue remained unknown, and the patients have persistent hyperparathyroidism., Conclusions: We showed that SVS is clinically useful in patients with persistent or recurrent hyperparathyroidism when the noninvasive localization studies do not clearly localize the abnormal parathyroid glands.

Objective: Although anterior circulation disease has both medical and surgical treatment options, management of vertebrobasilar disease has predominantly had only medical options. Some patients remain symptomatic despite medical treatment, and angioplasty has been demonstrated to relieve critical stenoses. However, the elative safety and effectiveness of medical and surgical treatments is not clearly known. This report reviews the clinical characteristics, indications, and procedural risks of intracranial angioplasty in a series of patients with symptomatic posterior circulation ischemia., Methods: All patients undergoing angioplasty for critical intracranial vertebral or basilar artery stenosis at the University of California at San Francisco Medical Center between June 1986 and July 1999 were included in a retrospective record review. Clinical features and procedural complications were recorded., Results: Angioplasty was performed on 25 vessel lesions in 25 patients in whom medical therapy had failed. The patients ranged in age from 50 to 87 years. Of the 25 stenoses, 10 were intracranial vertebral, 9 vertebrobasilar junction, and 6 basilar in location. Angioplasty was effective in reducing the degree of stenosis by more than 40% in all 25 vessels. The overall risk of stroke or death was 28%, and the risk of disabling stroke or death was 16%., Conclusion: Intracranial posterior circulation angioplasty is effective in the reduction of stenosis and can be performed with relative safety. Angioplasty can be considered as a treatment option in patients with recurrent ischemic symptoms despite medical therapy.

Purpose: To describe the endovascular treatment and clinical outcome in patients with indirect carotid cavernous fistulas (CCFs) over a 15-year period. To our knowledge, this is the largest series in the medical literature., Design: Interventional case series., Methods: A retrospective evaluation of 135 consecutive patients who underwent examination and treatment for indirect CCF was performed. Patients received independent evaluations by ophthalmologists, neurologists, or neuro-ophthalmologists before, during, and after endovascular treatment. Patients initially received noninvasive imaging followed by cerebral arteriography for definitive diagnosis and stratification by angiographic risk factors. Endovascular treatment was performed in 133 (98%) patients and clinical follow-up was achieved in 135 (100%) patients on an average of 56 +/- 4.3 months (range: 2 months-14 years). Angiographic follow-up was performed in 72 (54%) patients with ongoing symptoms or a history of fistula with high-risk angiographic features. Arteriographic cure with long-term clinical outcome is summarized by modified Rankin scale (mRS) and Barthel index (BI)., Results: At a mean follow-up of 56 months, 121 (90%) patients were clinically cured. At latest clinical follow-up, 131 (97%) patients showed good recovery (mRS, 1-2; BI 90-100), one (1%) had moderate disability (mRS, 3; BI, 50-60), and three (2%) (mRS, 4; BI, 40-50) were severely disabled. Procedure-related permanent morbidity was 2.3%. There was no operative mortality., Conclusions: With the observed favorable outcomes and low rate of procedural morbidity in this patient population with long-term angiographic and clinical follow-up, endovascular therapy should be the primary treatment for patients with indirect (dural) fistulas of the cavernous sinus.

Spinal cord vascular malformations are often a cause of spinal myelopathy. Endovascular surgical approaches to spinal cord vascular malformations have become an important adjunct and often the primary treatment of these disorders. Spinal cord vascular malformations may be divided into several categories based on their anatomy and location. They may present with a wide range of symptoms far removed from the vascular pathology. Early recognition and treatment can effect a better outcome and often reverse presenting neurologic deficits. Emerging magnetic resonance imaging techniques allow visualization of flow voids, some vascular anatomy, and intramedullary pathology and are a good screening modality. However, selective diagnostic spinal angiography remains the study of choice to diagnose and elaborate on the anatomy and potential treatment protocols. Rapidly evolving endovascular techniques and technology are revolutionizing the treatment of vascular pathology in the central nervous system, either as an adjunct to traditional neurosurgical techniques or as definitive therapy. We review the diagnosis and treatment options for spinal cord vascular malformations.

Osteoporosis is a debilitating disease that occurs in epidemic proportions in Western societies and has a large economic impact. Percutaneous vertebroplasty is successful in alleviating subacute and chronic pain caused by osteoporotic compression fractures and pathological vertebral fractures from tumor infiltration. The technique is safe and can be performed on an outpatient basis utilizing high-resolution fluoroscopy.

Background and Purpose: Several studies have shown that procedural outcomes are better at high-volume institutions, possibly due to greater physician experience (learning) or practice (repetition). Our purpose was to determine whether outcomes for coil embolization improved with the experience of the practitioner, after adjusting for the perceived risk of treatment., Methods: We identified all unruptured aneurysms treated with coil embolization at our institution from 1990 through 1997. A clinical nurse specialist abstracted the characteristics from cases that met the entry criteria. Two neurologists independently determined the complications by using definitions established a priori. The influence of experience of the treating-physician on complications was evaluated with univariate and multivariable logistic regression analyses., Results: Sixteen complications occurred in 94 patients (17%) treated with coil embolization. Complications occurred in 53% of the first five cases that each of three physicians treated, and in 10% of later cases (P <.001). After an adjustment for all other predictors, including physician assessment of the risk of the procedure, the odds of a complication decreased with increasing physician experience (odds ratio, 0.69 for every five cases treated; 95% confidence interval: 0.50, 0.96; P=.03)., Conclusion: The risk of complications with coil embolization of unruptured aneurysms appears to decrease dramatically with physician experience. Because the physicians in this study were highly experienced in other endovascular techniques at study onset, the rate of learning may not be generalizable to other centers.

Background: Patients harboring a brain arteriovenous malformation (BAVM) often have coexisting arterial aneurysms. Experts have argued about the clinical significance of these aneurysms, which may be important for risk stratification in patient management and clinical trials. We studied the association between coexisting aneurysms and initial presentation with intracranial hemorrhage (ICH) in patients with BAVM evaluated at two tertiary-care centers., Methods: Demographic and clinical data were collected from a prospective series of patients evaluated for BAVM at the University of California, San Francisco (UCSF; n=82), and Columbia-Presbyterian Medical Center, New York (CPMC; n=254). Using multivariate logistic regression, we examined the independent association between ICH presentation and the presence of a coexisting aneurysm, and compared the association at the two hospitals., Results: Aneurysms were associated with 28 BAVMs at UCSF (34%) and 74 at CPMC (29%; P=0.39). Initial presentation with ICH was associated with the presence of a coexisting aneurysm at CPMC (odds ratio 1.8, 95% confidence interval 1.0 to 3.0, P=0.044). The opposite trend was observed at UCSF (odds ratio 0.4, 95% confidence interval 0.2 to 1.1, P=0.085). We observed an interaction by site involving the association between ICH presentation and aneurysm (P=0.016)., Conclusion: Although many BAVM characteristics were similar at the referral centers studied, the association between initial presentation with ICH and coexisting aneurysms was not. This heterogeneity between populations undermines the validity of inferences on the role of aneurysms from any single referral series, and emphasizes the complexity in creating BAVM risk-stratification models that incorporate aneurysms.

Bow hunter stroke, which is characterized by transient vertebrobasilar ischemia brought on by head turning, is an unusual condition usually caused by structural abnormalities at the craniocervical junction. The authors present a case in which compression of the left vertebral artery (VA) at the C4-5 level was caused by a laterally herniated intervertebral disc. A 56-year-old man presented with a 6-month history of dizziness and syncope when he turned his head 45 degrees or more to the left. Transcranial Doppler (TCD) ultrasonography demonstrated decreased blood flow through the left VA, and angiography revealed an occlusion of the left VA at the C4-5 level, both when the patient turned his head to the left. Via an anterior cervical approach, the VA canal was unroofed through the transverse foramina to decompress the left VA at C4-5; intraoperatively, the left VA was found to be compressed by a laterally herniated cervical disc fragment. To the best of the authors' knowledge this is the first report of a laterally herniated cervical disc causing bow hunter stroke. The use of TCD may be of value in the diagnosis and management of the disorder, and herniated cervical disc must be included in the roster of potential causes for this rare disease.

An association between dural arteriovenous fistula and cerebral sinus thrombosis is reported. It is clear in several cases that thrombosis precedes the development of the fistula while it is unclear that it occurs in every case. The authors report a case of a woman with sinus thrombosis and presence of prothrombin gene mutation who subsequently developed a large dural arteriovenous fistula. Various possible factors involved in the pathogenesis of a dural fistula are discussed, with emphasis on underlying thrombophilia and oral contraceptive use in this patient.

Objectives: PHACE is an acronym coined to describe a neurocutaneous syndrome encompassing the following features: posterior fossa brain malformations, large facial hemangiomas, arterial anomalies, cardiac anomalies and aortic coarctation, and eye abnormalities. We evaluated the spectrum of disease and significance of potential underlying brain anomalies among affected children., Study Design: The records of 14 patients with PHACE syndrome, evaluated between 1995 and 2000, were retrospectively reviewed. A literature review revealed 116 additional cases., Results: PHACE syndrome represents a spectrum of anomalies, because most affected children have only one extracutaneous manifestation. The syndrome is associated with a high incidence of arterial and structural central nervous system anomalies with secondary neurologic sequelae. The potential for progressive neurovascular disease also exists among those patients with anomalous vasculature., Conclusion: PHACE syndrome should be considered in any infant presenting with a large, segmental, plaque-type facial hemangioma. Children at risk should receive careful ophthalmologic, cardiac, and neurologic assessment.