Embolization of cerebral aneurysms with a liquid embolus, EVAL mixture: report of three cases

Bleb Embolization of Ruptured Cerebral Aneurysms with Coils and n-Butyl Cyanoacrylate Following Proximal Flow Control: Two Case Reports

Objective

Morphologically challenging cerebral aneurysms cannot be treated through standard endovascular procedures. We report two cases of ruptured aneurysms treated using coils and n-butyl cyanoacrylate (NBCA).

Case Presentations

Case 1 was an 80-year-old woman diagnosed with a subarachnoid hemorrhage (SAH). An angiogram revealed a large and wide-necked basilar artery bifurcation aneurysm. Bilateral superior cerebellar and posterior cerebral arteries (PCAs) originated from the aneurysmal wall. A 3-mm-diameter bleb was detected on the aneurysmal fundus. The bleb enlarged 1 month following coil insertion. During the second treatment, we infused a small volume of 33% NBCA into the coil-framed bleb following proximal flow control of the bilateral vertebral arteries (VAs). The complete bleb obliteration was confirmed by the angiogram at 6 months later. The coil shape was followed up via plane X-ray for 5 years. No rebleeding occurred. Case 2 was a 41-year-old woman diagnosed with SAH. An angiogram revealed a dissecting aneurysm of the left PCA (P1 and P2 segments) accompanying a bleb on the P1 segment. Endovascular treatment was performed, and a coil was inserted into the bleb, infusing 33% NBCA into the coil frame following proximal flow control of bilateral VAs and the right internal carotid artery. Angiograms conducted at 3 months, 1 year, and 9 years and an MRA conducted 12 years later revealed a lack of bleb recanalization.

Conclusion

We developed a Coil and NBCA technique to obliterate ruptured blebs following proximal flow control. This technique can be considered an effective alternative for treating morphologically challenging cerebral aneurysms.

Which Patients with Aneurysms Involving the a1-a2 Segment of the Anterior Inferior Cerebellar Artery Would Benefit from Parent Artery Occlusion?

Anterior inferior cerebellar artery (AICA) trunk aneurysms are rare entities. Given the eloquence of the AICA in supplying the cerebellum and brainstem, in theory, sacrifice or occlusion of the a1-a2 segment in lesions involving the AICA may lead to various complications. However, some patients might experience no complication or favorable recovery. The subgroup of patients who would benefit from parent artery occlusion (PAO) among those with aneurysms involving the a1-a2 segment of the AICA remains to be explored. In this report, we present 2 cases of AICA dissecting aneurysms at the a1-a2 segment that were successfully occluded via coiling without postprocedural complications. A comprehensive literature review was also performed on patients with AICA aneurysms with occlusion at the a1-a2 segment. Sixteen patients were identified, and all of the cases had satisfactory outcomes. Of these patients, 11 of 16 (68.75%) had no neurologic deficits, and 5 of 16 (31.25%) had acceptable neurologic deficits. The prognosis was associated with collateral circulation of the AICA, and collateral circulation was discussed. In case of an a1-a2 aneurysm that is hard to occlude without sacrificing the parent artery, careful hemodynamic and morphologic evaluation for collateral flow is warranted. If collateral flow is demonstrated or the aneurysm is flow-related with cerebellar arteriovenous malformation, PAO of the a1-a2 segment can be an acceptable option.

Transarterial Embolization of Cerebrospinal Lesions with Liquid Coils

We report our experience with endovascular embolization using liquid coils. Twenty-two transarterial embolization procedures were performed with these coils in 20 patients with cerebrospinal vascular or neoplastic lesions. The coils were delivered into the target vessels under fluoroscopic monitoring through a microcatheter by manual injection and flushing with saline.

Subsequent surgical resections of embolized lesions were performed in 14 cases, and radiosurgery for two. Complete obliteration of the target vessels were accomplished in all cases without complications. Passage through the microcatheter and delivery of the coil was smooth. Proximal protrusion of the coil occurred during the procedure, and a combination of other embolic materials was necessary to completely occlude large vessels in 9 cases.

The embolized lesions were easily resected in the following neurosurgery. Liquid coils were safe and effective as an embolic material in use prior to surgery or radiosurgery.

Endovascular treatment of AICA flow dependent aneurysms. A report of three cases and review of the literature

Peripheral anterior inferior cerebellar artery (AICA) aneurysms are rare, accounting for less than 1% of all cerebral aneurysms. To our knowledge 34 flow-related cases including the present study have been reported in the literature. Three patients harbouring four flow dependent aneurysms were referred to our institution. Two patients presented with subarachnoid hemorrhage, one presented with cerebellar manifestations. They were all treated by endovascular embolization of the aneurysm as well as the parent artery using liquid embolic material. Two cases were embolized using NBCA, Onyx was used in the third case. No bleeding or rebleeding were encountered during the follow-up period which ranged from five to nine months. One patient developed facial palsy, cerebellar symptoms and sensorineural hearing loss. The remaining two cases did not develop any post treatment neurological complications. Endovascular management of flow-dependent AICA aneurysms by parent artery occlusion is feasible and efficient in terms of rebleeding prevention. Post embolization neurological complications are unpredictable. This depends upon the adequacy of collaterals from other cerebellar arteries.

Endovascular treatment of cerebral aneurysms associated with arteriovenous malformations

BACKGROUND AND PURPOSE

In univariate survival analysis, coexisting aneurysms was associated with a significantly increased risk of hemorrhage in AVMs. We report here on our clinical experience with AVMs associated with arterial aneurysms that were managed by endovascular treatment.

METHODS

To determine the incidence of associated aneurysms, the authors reviewed 366 consecutive patients with AVMs managed between 1999 and 2009. In 86 (23.5%) of these 366 patients, 55 intranidal aneurysms and 40 proximal aneurysms were observed. Targeted endovascular treatment with coils, n-butylcyanoacrylate(NBCA) and Onyx was performed for patients in this series, using a standard protocol. We reviewed the treatment plans, radiological findings and clinical courses of 86 patients suffering AVM associated with aneurysm.

RESULTS

Ninety-five aneurysms in 86 patients with AVMs were enrolled in this study. Hemorrhage was the most frequent presenting symptom (69 patients, 80.2%). Bleeding was caused by an AVM nidus in 44 cases, aneurysm rupture in 20 and an undetermined origin in 5. Four patients were treated for associated aneurysm with coils followed by AVM embolization and 82 patients were treated with NBCA or Onyx embolization. There were total of 3 complications (3.5%) clinically significant complications in this series. Excellent or good outcomes (Glasgow Outcome Scale ≥ 4) were observed in 63 (73.3%) patients at discharge. Neurological deficits (Glasgow Outcome Scale 1-4) were 16.6% at discharge.

CONCLUSION

Endovascular treatment can be adequately used for cerebral aneurysms associated with AVMs as an adjunct to microsurgery and radiosurgery.

Intraventricular hemorrhage secondary to intranidal aneurysm rupture-successful management by arteriovenous malformation embolization followed by intraventricular tissue plasminogen activator: case report

BACKGROUND AND IMPORTANCE

Intraventricular hemorrhage related to arteriovenous malformation (AVM) rupture is associated with significant morbidity and mortality. Intraventricular tissue plasminogen activator (tPA) has been used to treat spontaneous intraventricular hemorrhage. We demonstrate the successful application of endovascular occlusion to seal the rupture site of an AVM followed by intraventricular tPA.

CLINICAL PRESENTATION

A 32-year-old woman presented with a right frontoparietal parasagittal AVM abutting the motor cortex. The AVM was diagnosed when the patient was 13 years old, and she initially underwent conservative management. At the age of 30, the patient suffered an intracranial hemorrhage, leaving her with left hemiparesis. After rehabilitation, the patient regained ambulation; however, she remained spastic and hyperreflexic on the left side. Two years after her major hemorrhage, she presented for elective treatment of her AVM. The patient was advised to undergo staged embolization before surgical resection of her AVM. The initial embolization was uneventful. A second embolization was complicated by intraventricular hemorrhage and coma. The patient was treated with placement of an external ventricular drain followed by embolization of intranidal aneurysm. After embolization of the intranidal aneurysm the ruptured, the patient was treated with intraventricular tPA. The patient had rapid clearance of the intraventricular hemorrhage and significant improvement in her neurological examination, following commands 24 hours later and returning almost to baseline.

CONCLUSION

This case demonstrates the feasibility of treating AVM-related intraventricular hemorrhage with tPA if the rupture source can be confidently sealed interventionally. This strategy can be lifesaving but needs further study to ensure its safety.

Assessment of EmboGel--a selectively dissolvable radiopaque hydrogel for embolic applications

PURPOSE

To evaluate the embolic properties of an alginate-based embolic biomaterial (EmboGel) and its solvent (EmboClear) in treatment of aneurysms.

MATERIALS AND METHODS

EmboGel is a mixture of iohexol and alginate that polymerizes into a hydrocoil when delivered through a coaxial catheter with a distal mixing tip, exposing alginate to a calcium chloride solution. In contrast to previously reported embolic agents, EmboGel can be selectively dissolved by EmboClear, a mixture of the enzyme alginate lyase and ethylenediaminetetraacetic acid (EDTA). The embolic and contrast properties of EmboGel were assessed in in vitro models of saccular aneurysm and an aortic aneurysm endoleak. The dissolvability of EmboGel with EmboClear was assessed further after endovascular delivery in the New Zealand white rabbit in the native aortoiliofemoral territory, a created saccular aneurysm, and the native carotid arteries.

RESULTS

EmboGel effectively filled aneurysm cavities in the case of stent excluded saccular and fusiform aneurysms. EmboGel was readily dissolved by EmboClear in vitro and after in vivo embolization. When the distal abdominal aorta and pelvic arteries were occluded with EmboGel, within 1 minute of EmboClear infusion, patency of the aorta and most of the pelvic circulation was regained as noted by angiography. Embolization in the subclavian artery and numerous distal branches was rapidly dissolved by EmboClear. Finally, the carotid artery occluded with EmboGel regained patency after administration of EmboClear.

CONCLUSIONS

EmboGel is a dissolvable alginate-based biomaterial that can be used for numerous embolic applications. EmboGel can be selectively dissolved with EmboClear, a solution of alginate lyase and EDTA.

Comparison of N-Butyl Cyanoacrylate and Onyx for the Embolization of Intracranial Arteriovenous Malformations: Analysis of Fluoroscopy and Procedure Times

Objective:

Intracranial arteriovenous malformations (AVM) may be managed through staged preoperative embolization and resection. Two commonly used liquid embolics are N-butyl cyanoacrylate (nBCA; Cordis Microvascular, Inc., New Brunswick, NJ) and Onyx (ev3, Inc., Irvine, CA). We sought to compare the utility of these agents in terms of fluoroscopy and procedure times.

Methods:

All intracranial AVMs embolized from 2002 to 2006 at the University of Florida were included in this study. Patients were stratified into three treatment groups: nBCA, Onyx, and patients who received both nBCA and Onyx during separate embolizations. Cohorts were compared by sex, age, Spetzler-Martin grade, AVM volume, fluoroscopy time, procedure time, surgical blood loss, and complications.

Results:

A total of 182 embolizations were performed on 88 patients (nBCA, 60 patients and 106 procedures; Onyx, 20 patients and 43 procedures; and nBCA/Onyx, eight patients and 16 nBCA and 17 Onyx procedures). There were no significant differences in patient demographics, AVM volumes, and Spetzler-Martin grades. Mean fluoroscopy and procedure times were increased for Onyx (57 min; 2.6 h) compared with nBCA (37 min; 2.1 h) embolizations (P < 0.0001 and P = 0.001, respectively). Cumulative mean fluoroscopy time was increased for Onyx (135 min) and nBCA/Onyx (180 min) cohorts relative to nBCA (64 min; P < 0.0001). Cumulative mean procedure time was increased in the nBCA/Onyx group (10.4 h) compared with nBCA (3.7 h) and Onyx (5.4 h; P< 0.0001). Seventy patients (80%) underwent AVM resection. No significant differences in surgical blood loss or complication rates were observed among the cohorts.

Conclusion:

Onyx AVM embolization requires increased fluoroscopy and procedure times compared with nBCA. Further investigation is necessary to justify increased radiation exposure and procedure time associated with Onyx.

Systematic review: endoluminal therapy for gastro-oesophageal reflux disease: evidence from clinical trials

During the last few decades many endoscopic interventions have been developed as an alternative for the treatment of gastro-oesophageal reflux disease (GORD). In many countries, these interventions are thus being performed in the general clinical setting. The aim of this study is to systematically review the evidence on the effect of endoscopic therapies for GORD. A systematic search of the literature on this subject in English, indexed in MEDLINE (1966 to May 2007) and in the Cochrane Library, was carried out. For the study selection, retrospective and prospective open-label and randomized, sham-controlled trials were taken into account. The exclusion criteria included the following: case series that included fewer than 10 patients, abstracts, studies involving children or those with a follow-up shorter than 3 months. For data extraction, two reviewers, using standardized forms, independently abstracted data on study design and methods, population, sample size, function studies (e.g. pH-metry), type of endoscopic treatment, follow-up, health-related and quality of life scores, outcomes and complications. Data synthesis involved the following: 43 studies, including four randomized, sham-controlled trials that met the inclusion criteria, out of 4182 citations. The primary end point in most studies was the reduction of the use of proton pump inhibitors (PPIs) by more than 50%. In view of these findings, the majority of studies suggested the efficacy of endoluminal therapies for the control of symptoms in GORD. In the sham-controlled studies, the effect of placebo was, nevertheless, as high as 50%. Most studies were small feasibility studies, with follow-ups of less than 1 year. No study comparing endoscopic techniques with other established treatment options such as PPIs existed. All endoscopic therapies were associated with a small but important percentage of mild to severe complications, which included perforation, abscess and death. In conclusion, the data from most of the short-term follow-up and the few sham-controlled studies demonstrate that subgroups of patients experienced improvement or resolution of typical GORD symptoms and decreased PPI usage. Currently, however, there are not enough scientific and clinical data on safety, efficacy and durability to support the use of endoluminal therapies for GORD in routine clinical practice.

Volume changes of experimental carotid sidewall aneurysms due to embolization with liquid embolic agents: a multidetector CT angiography study

Iodine-containing polyvinyl alcohol polymer (I-PVAL) is a novel precipitating liquid embolic that allows for artifact-free evaluation of CT angiography (CTA). As accurate aneurysm volumetry can be performed with multidetector CTA, we determined volumes of experimental aneurysms before, immediately after, and 4 weeks after embolization of 14 porcine experimental carotid sidewall aneurysms with this liquid embolic. An automated three-dimensional software measurement tool was used for volumetric analysis of volume-rendering CTA data. Furthermore, intra-aneurysmal pressure changes during liquid embolization were measured in four silicone aneurysms and potential polymer volume changes within 4 weeks were assessed in vitro. Liquid embolic injection was performed during temporary balloon occlusion of the aneurysm neck, resulting in a mean occlusion rate of 98.3%. Aneurysms enlarged significantly during embolization by 61.1 +/- 28.9%, whereas a significant shrinkage of 5.6 +/- 2.7% was observed within the follow-up period. Histologic analysis revealed an inflammatory foreign body reaction with partial polymer degradation. In silicone aneurysm models, intra-aneurysmal pressure remained unchanged during liquid embolic injection, whereas balloon inflation resulted in a mean pressure increase of 31.2 +/- 0.7%. No polymer shrinkage was observed in vitro. The aneurysm enlargement noted was presumably due to pressure elevation after balloon inflation, which resulted in dilatation of the weak venous wall of the newly constructed aneurysm--another shortcoming of this experimental aneurysm model. The volume decrease after 4 weeks expressed partial polymer degradation.

Intrinsically radiopaque iodine-containing polyvinyl alcohol as a liquid embolic agent: evaluation in experimental wide-necked aneurysms

Object

To evaluate iodine-containing polyvinyl alcohol (I-PVA) as a precipitating liquid embolic agent, implant characteristics—including radiopacity, setting behavior, and biocompatibility—were studied in an aneurysm model in swine.

Methods

Twelve broad-based carotid artery (CA) sidewall aneurysms were surgically constructed in six pigs. Iodine-containing polyvinyl alcohol dissolved in dimethyl sulfoxide (DMSO) was injected during temporary balloon occlusion bridging the aneurysm neck. Control angiography as well as multidetector row computerized tomography (CT) angiography was performed after 4 weeks. Harvested aneurysms were investigated histopathologically and by 3-tesla high-field magnetic resonance (MR) imaging. The mean degree of aneurysm occlusion achieved was 96%. In two aneurysms a minimal protrusion of I-PVA into the CA lumen was observed. During one embolization, leakage of the liquid embolic agent due to DMSO-induced damage of the microcatheter resulted in CA occlusion. Aneurysms embolized with I-PVA could be discriminated clearly from the parent artery on CT angiograms because there was no beam-hardening artifact. High-field MR imaging allowed a detailed depiction of the liquid embolic distribution within the aneurysm. Histologically, a mild to moderate inflammatory response was found in successfully embolized aneurysms, and the polymer mass was frequently covered by a membrane of fibroblasts and endothelial cells.

Conclusions

Iodine-containing polyvinyl alcohol is a ready-to-use liquid embolic agent clearly visible under fluoroscopy; additives are not required. The setting behavior allows for controlled delivery in aneurysm cavities. Histological studies performed 4 weeks after embolization revealed no sign of toxic tissue response to the liquid embolic agent. Overall, I-PVA exhibits interesting implant characteristics in that radiopaque admixtures are not necessary, thus allowing for artifact-free evaluation of treated aneurysms by using CT and MR angiography.

Endovascular treatment of experimental cerebral aneurysms using thermoreversible liquid embolic agents

SUMMARY

We have developed a new embolic agent, thermoreversible gelation polymer (TGP). This polymer is unique in that solidification occurs at body temperature. The utility of this new liquid embolic agent for the treatment of large experimental aneurysms was evaluated angiographically. TGP remains liquid at temperatures below the sol-gel transition temperature (TT) and becomes gelatinous above the TT. TGP can also be used to slowly deliver biologically active substances such as growth factors or engineered cells. In this study, TGP was mixed with radiopaque material without solvent. Bilateral common carotid arteries of swine (n=5) were used for surgical creation of lateral aneurysms, then 1 aneurysm in each animal was embolized using TGP without any protection device. The remaining untreated aneurysm in each animal was used as a control. All aneurysms were successfully embolized using TGP. No distal migration of TGP was observed when aneurysms were embolized without using protection devices. TGP can be safely used to embolize experimental aneurysms. Embolization of aneurysms with a protection device needs to be evaluated. Further modifications such as mechanical stability and use as a drug delivery system will be necessary prior to the clinical application of TGP.

Multiple anterior inferior cerebellar artery aneurysms associated with an arteriovenous malformation: case report

BACKGROUND

Multiple aneurysms of the proximal part of the anterior inferior cerebellar artery (AICA) associated with a distal arteriovenous malformation (AVM) are extremely rare lesions.

METHODS

A 52-year-old man was admitted because of sudden headache. Neurological examination revealed ataxia. Computed tomography scan showed a right cerebellar and subarachnoid hemorrhage. Vertebral angiograms demonstrated 3 small aneurysms at the proximal part of the AICA and distal AVM.

RESULTS

A right-sided lateral retromastoid suboccipital craniectomy was performed. We observed strangulation and obliteration at the AICA due to multiple clipping for aneurysms. Thus, aneurysms could not be clipped. At 11 years after bleeding, vertebral angiograms showed that 3 aneurysms had slightly enlarged but the AVM remained unchanged. To date, the patient is still doing well except for dizziness.

CONCLUSION

This association is very rare at the AICA level, and definitive treatment of this association is sometimes complex.

Volume Determination of Intracranial Aneurysms Using 16-Row Multislice Computed Tomography Angiography

OBJECTIVE

To assess multislice computed tomography (CT) angiography for volume determination of intracranial aneurysms.

METHODS

Submillimetric 16-row multislice CT angiography was performed with optimized scan parameters on precision spheres and a soft carotid artery model harboring 3 aneurysms connected to a pulsatile circuit. The CT angiography images were produced using optimized techniques for axial, multiplanar reformation, maximum intensity projection, surface-shaded display, and volume-rendered images. Measurements were made with electronic precision calipers by segmentation according to the method of Cavalieri and by the use of automated volumetric analysis software.

RESULTS

Segmentation resulted in precise and accurate volume estimates of aneurysms, but small volumes were underestimated and evaluation time was long (36:44 minutes). Automated volume evaluation from volume-rendered reconstructions also resulted in low measurement error, although the evaluation process was significantly faster (3:25 minutes; P < 0.0001).

CONCLUSIONS

The use of an automated volume analysis tool on volume-rendered reconstructions is recommended for time-efficient volume assessment of intracranial aneurysms.

Emerging Concepts in the Treatment of Intracranial Aneurysms: Stents, Coated Coils, and Liquid Embolic Agents

ENDOVASCULAR TECHNIQUES FOR the treatment of intracranial aneurysms are rapidly evolving. Modifications of more traditional coils have been introduced. Such modifications include newer coils coated with various polymers to increase both coil thrombogenicity and degree of aneurysm packing. In addition, newer coil designs aimed at improving the conformability of the coil to the aneurysm have been used with promising preliminary results. The availability of a newer generation of stents specifically designed for intracranial navigation allows for more effective treatment of aneurysms with wide necks, which usually have been considered unsuitable for optimal endovascular treatment. Endovascular alternatives to coil embolization, such as liquid embolic materials, also have been explored for the treatment of intracranial aneurysms, with varying results. We summarize the rationale for use of these newer devices and early clinical experiences. Areas of current research and future directions of endovascular aneurysm treatment also are discussed.

Endoscopic Therapies For Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is a chronic condition affect-ing over 7% of the US population. The primary objective of therapy is symptom relief, with secondary goals to heal esophagitis, prevent reflux-related complications, and maintain remission. There are several new endoscopic therapies (ETs) for treatment of GERD, generating considerable interest. An outpatient procedure, performed without an incision and general anesthesia, is attractive to patients and these therapies are being rapidly introduced, despite lack of long-term follow-up and randomized trials. In this article, the authors review endoscopic procedures, including technical aspects, mechanisms of action, safety, efficacy, and tolerability. Patient selection and relevant human studies are reviewed to clarify advantages and disadvantages of ET compared with conventional procedures.

A contribution to the controversy over dimethyl sulfoxide toxicity: anesthesia monitoring results in patients treated with Onyx embolization for intracranial aneurysms

Onyx injection is a new technique for embolization of cerebral aneurysms that is involved in a controversy about the 'toxicity' of its solvent, dimethyl sulfoxide (DMSO). We retrospectively studied 38 patients treated for aneurysms with the liquid polymer, Onyx. Induction was with propofol, fentanyl and vecuronium, and anesthesia was maintained with isoflurane in O2 and N2O. The patients were given 500 ml of fluid after induction, and bradycardia was prevented in order to keep patients hyperdynamic. Electrocardiography (ECG), non-invasive blood pressure (NIBP), pulse oximetry, core temperatures, invasive blood pressure (BP), etCO2, and urine output were monitored throughout the intervention. Heart rate and BP changes in response to balloon inflation, DMSO injection, Onyx injection and balloon deflation were recorded. The patients were followed with serial neurological examinations, computerized tomography and/or magnetic resonance imaging postoperatively for evidence of any neurological injury. Cumulative DMSO doses were always well under previously implicated doses for systemic toxicity. No changes implicating toxic reactions were observed during DMSO and Onyx injections. Balloon-induced changes returned to baseline within 1 min of balloon deflation. Technique-related permanent morbidity occurred in two patients (worsening of cranial nerve palsies in one and monocular blindness in another) and intracranial hemorrhage with resulting death in one patient. All patients showed a tendency to oxygen desaturation, but this finding did not cause any clinical consequence. Anesthesiologists need to be vigilant in monitoring patients treated with techniques that are new or are being developed. We have seen no evidence of toxicity or any anesthetic complications in our group of patients, our only clinical concern being a tendency to oxygen desaturation, which may be explained by the inhalational elimination of DMSO.

Anteroinferior Cerebellar Artery Aneurysms: Surgical Approaches and Outcomes—A Review of 34 Cases

OBJECTIVE:

Anteroinferior cerebellar artery (AICA) aneurysms are rare lesions whose treatment requires expertise in vascular, endovascular, and cranial base surgery. This article presents the largest series treated at one center.

METHODS:

We retrospectively analyzed presenting symptoms, aneurysm characteristics, surgical approaches, postoperative outcomes, and the application of endovascular techniques.

RESULTS:

We found 32 patients with 34 AICA aneurysms (11 men and 21 women; age range, 6–77 yr; mean age, 51 yr). Twenty-one aneurysms had ruptured; 13 were unruptured. Seven of the unruptured aneurysms presented with brainstem compression, and six were found incidentally. Surgical approaches included the retrosigmoid, far-lateral transcochlear, translabyrinthine, and orbitozygomatic. Eighteen patients (56%) had neurological complications. Thirty aneurysms were at proximal locations, and four were distal. Intraoperative hypothermic cardiac arrest was used to clip eight giant aneurysms. Follow-up was available in 56% of the patients for a mean of 41 months. The mean Glasgow Outcome Scale scores at discharge were not significantly different from the patients' status at their initial assessment.

CONCLUSION:

We recommend the standard retrosigmoid approach for treating small to medium aneurysms involving the lower two-thirds of the clivus or distal AICA aneurysms. Cranial base approaches are recommended for large or giant aneurysms or for those proximal to the emergence of the AICA from the basilar trunk. Hypothermic cardiac arrest facilitates dissection of giant aneurysms. Endovascular treatment is a useful adjunct for treating residual aneurysms but did not provide definitive treatment in any of our patients.

[Endoscopic therapy methods for gastroesophageal reflux]

Gastroesophageal reflux disease (GERD) is prevalent in 10% of the population. In addition to the established therapy, endoscopic antireflux procedures have been developed to improve the gastroesophageal reflux barrier. This can achieved by endoscopically placed sutures, application of radio frequency energy, or injection of biocompatible materials. These new techniques might be effective in some patients with GERD. To date, there are limited data on the effectiveness and safety of these methods. During a follow-up of 1-2 years, subjective parameters improved in 70-75% of the test patients such that no antisecretory treatment was required. Further, randomized, placebo-controlled studies are needed for objective evaluation of these promising new methods.

Evolution of Neuroendovascular Intervention: A Review of Advancement in Device Technology

NEUROENDOVASCULAR SURGERY IS a rapidly evolving field. Each year, numerous improvements are made in the endovascular surgeon's armamentarium. This evolution in technology, which is occurring at a dizzying pace, addresses many of the current limitations of neuroendovascular approaches. The potential to improve the outcomes of our patients is tremendous, particularly because one of the most common and most devastating neurological disorders, ischemic stroke, remains largely untreated. This article presents several of the new technologies that are currently being investigated or are under development and have the potential to lead to major advances in endovascular approaches for the treatment of intracranial and extracranial diseases.

CT angiography, MR angiography and rotational digital subtraction angiography for volumetric assessment of intracranial aneurysms. An experimental study

The purpose of our experimental study was to assess the accuracy and precision of CT angiography (CTA), MR angiography (MRA) and rotational digital subtraction angiography (DSA) for measuring the volume of an in vitro aneurysm model. A rigid model of the anterior cerebral circulation harbouring an anterior communicating aneurysm was connected to a pulsatile circuit. It was studied using unenhanced 3D time-of-flight MRA, contrast-enhanced CTA and rotational DSA angiography. The source images were then postprocessed on dedicated workstations to calculate the volume of the aneurysm. CTA was more accurate than MRA (P=0.0019). Rotational DSA was more accurate than CTA, although the difference did not reach statistical significance (P=0.1605), and significantly more accurate than MRA (P<0.00001). CTA was more precise than MRA (P=0.12), although this did not reach statistical significance. Rotational DSA can be part of the diagnosis, treatment planning and support endovascular treatment of intracranial aneurysms. The emerging endovascular treatment techniques which consist of using liquid polymers as implants to exclude aneurysms from arterial circulation would certainly benefit from this precise measurement of the volume of aneurysms.

Treatment of pelvic arteriovenous malformations with ethylene vinyl alcohol copolymer (Onyx)

In this article, two successful embolizations of large pelvic arteriovenous malformations (AVMs) with use of ethylene vinyl alcohol, a radiopaque, nonadhesive liquid casting agent, are reported. Both patients presented with large symptomatic pelvic AVMs requiring therapy. Coaxial microcatheter techniques were used to achieve complete success in one case and partial success in the other. Clinical success has been maintained in both patients at 2-year follow-up.

Aneurysm of the anterior inferior cerebellar artery (AICA) associated with high-flow lesion: report of two cases and review of literature

OBJECTIVE AND IMPORTANCE

Although aneurysms of the anterior inferior cerebellar artery (AICA) are rare lesions, their occurrence in combination with high-flow lesions in the same arterial territory is even more striking. Two cases of an AICA aneurysm in combination with a high -flow lesion are described.

CLINICAL PRESENTATION

In one case, a 52-year-old female presented with cerebellar syndrome as the result of a left-sided cerebellar tumor. Angiography revealed a highly vascularized tumor and a broad-based aneurysm at the offspring of the left AICA. In the second case, a 17-year-old female presented with a right-sided cerebellar hemorrhage. Angiography revealed a large peripheral AICA aneurysm and a distal arteriovenous malformation (AVM) fed by the AICA.

INTERVENTION

In the first case, a left lateral suboccipital craniotomy was performed and a highly vascularized tumor was removed. The AICA aneurysm could not be adequately clipped and was subsequently wrapped with muscle and reinforced with fibrin glue. Pathological examination of the tumor revealed a hemangioblastoma. Five years after surgery, the patient experienced a subarachnoid hemorrhage. Subsequent vertebral angiography revealed local enlargement of the known AICA aneurysm just at the superior aspect, but the patient refused further treatment. In the second case, the patient sustained a novel cerebellar rebleed while awaiting surgery. A right-sided lateral retromastoid suboccipital craniotomy was performed and the AICA aneurysm could be successfully clipped. More peripherally, the AVM with two draining veins could be totally removed. Postoperative angiography revealed no residual aneurysm or AVM.

CONCLUSION

Several aspects of these cases are discussed, such as the rare occurrence of AICA aneurysm and the contribution of high-flow lesions to the genesis of the AICA aneurysms.

Experimental evaluation of cellulose acetate NF and ethylene-vinyl alcohol copolymer for selective arterial embolization

PURPOSE

Studies were conducted in rabbits to evaluate two new liquid polymeric compounds developed for selective arterial embolization.

MATERIALS AND METHODS

The compounds consisted of cellulose acetate NF (Embolyx C) or ethylene-vinyl alcohol copolymer (Embolyx E) dissolved in anhydrous dimethyl sulfoxide (DMSO) containing 30% tantalum powder. Acute renal embolization was performed to determine an optimal method of administration and level of embolization. Kidneys were embolized with and without flow around the catheter. DMSO was also injected in the same manner. Tissue sections were examined radiographically and microscopically. Tumor embolization was performed to evaluate the efficacy of the polymers and compare their embolic effects with polyvinyl alcohol (PVA) particles and gelatin sponge (Gelfoam) powder. An embolic agent, saline, or DMSO was injected into the deep femoral artery feeding an intramuscular VX2 carcinoma. Animals were followed up for 3 weeks.

RESULTS

Viscosity and administration technique affected polymer distribution and depth of penetration. Embolization with the test polymers was quicker and more easily achieved than with PVA or Gelfoam, and no recanalization occurred. Both polymers were as effective as PVA particles for tumor ablation, but DMSO caused some vascular damage.

CONCLUSION

Although use of DMSO has some drawbacks, the results of this study warrant further investigation of the Embolyx polymers for tumor embolization.

Embolization of Aneurysms with a Liquid Material: An Experimental Study

The authors evaluated the embolization effects on experimental aneurysm models with a liquid material. This material is a mixture of poly (HEMA-co-MMA), Iopamidol, water and a small amount of ethyl alcohol.

We have satisfactorily treated over 30 cases of AVM with this material. Out of four solutions of different viscosity, we used the solution with the highest viscosity to prevent distal migration of the mixture. Glass models of aneurysms of 5 mm in diameter in pulsatile saline flow were embolized with the mixture under various conditions. When an IDC was placed in the aneurysm models, the mixture obliterated them completely and did not migrate out from the aneurysm models.

In this experimental study, it is suggested that the liquid material appears to be useful in embolizing cerebral aneurysms safely.