Endovascular treatment of cerebral dural arteriovenous fistulas with SQUID 12

Unusual anatomic variation: The posterior inferior cerebellar artery arising from the middle meningeal artery

An adult patient was admitted to our emergency department for a first episode of generalized tonic-clonic seizure. Computed tomography scan and magnetic resonance imaging showed a temporal intracranial hemorrhage and parenchymal edema caused by a dural arteriovenous fistula (DAVF), whose angioarchitecture was better understood through the DSA which showed as intriguing and rare vascular anomaly the origin of the posterior inferior cerebellar artery (PICA) from the middle meningeal artery (MMA). The endovascular treatment of the DAVF was then successfully performed.This case describes the first case of a PICA arising from the MMA in the literature and highlights as an accurate knowledge of vascular anatomy and its variations is essential for the endovascular treatment of the cerebrovascular diseases.

Penetration of Non-Adhesive Gel-like Embolic Materials During Dural Vessels Embolization According to Characteristics of Tantalum Powder

Tantalum powder is included in the composition of Non-Adhesive Gel-like Embolic Materials (NAGLEMs) for X-ray opacity. The duration of X-ray opacity during embolization is primarily associated with the particle size, which differs in the most used NAGLEMs-ONYX (Medtronic) and SQUID (Balt). NAGLEMs are widely used for the embolization of branches of the middle meningeal artery (MMA) in patients with chronic subdural hematomas (CSDHs). Considering the size (5-15 microns) of the target dural vessels, we assumed that not only the viscosity of NAGLEMs, but also the size and shape of tantalum granules may be important for the penetration of these gel-like embolic agents and determine their behavior. A notable discrepancy in size was observed. The medium-sized granules in the SQUID 18 sample (0.443 ± 0.086 microns, M ± SD) were found to be approximately ten times smaller than the tantalum granules in the ONYX 18 sample (5.2 ± 0.33 microns, M ± SD).Tantalum granules in SQUID 18 have a regular spherical shape; in ONYX 18 they have an irregular angular shape. When comparing the behavior of gel-like embolic agents of the same viscosity during MMA embolization in patients with CSDHs (an average age of 62.2 ± 14.3 years) in the group where SQUID 18 (n = 8) was used, the gel-like embolic agent in dural vessels demonstrated significantly greater penetration ability compared with the group where ONYX 18 (n = 8) was used. Accordingly, not only the viscosity of NAGLEMs, but also the size and shape of tantalum granules can have a significant effect on the penetration ability of gel compositions.

Safety and efficacy of newer liquid embolic agents Squid and PHIL in endovascular embolization of cerebral arteriovenous malformations and dural arteriovenous fistulas: A systematic review and meta-analysis

BACKGROUND

A wide range of liquid embolic agents has been used in endovascular treatment (EVT) of dural arteriovenous fistulas (dAVFs) and cerebral arteriovenous malformations (cAVMs). Newer liquid embolics, Squid (Balt) and PHIL (MicroVention), aim to improve the safety and efficacy of EVT of dAVFs and cAVMs.

OBJECTIVE

To assess the safety and efficacy of EVT of cAVMs and dAVFs using Squid or PHIL as an embolic agent.

METHODS

We searched major databases following PRISMA guidelines and included studies with ≥ five patients reporting on EVT of dAVFs and/or cAVMs using Squid or PHIL as embolic agent. We analyzed efficacy outcomes including complete occlusion, incomplete occlusion, and recurrence at follow up, and safety outcomes including procedure-related complications, morbidity, and mortality with a random-effects meta-analysis. Separate analyses were performed for cAVMs and dAVFs. Subanalyses were conducted for studies exclusively utilizing PHIL and those exclusively utilizing Squid, for both cAVMs and dAVFs.

RESULTS

Ten studies, comprising 214 patients (53.7% male), were found. Of these, 113 patients had 113 dAVFs, while 101 patients had 101 cAVMs. Complete occlusion rates following embolization were 91% for dAVFs and 32% for cAVMs. A subanalysis of dAVFs embolized solely with Squid and PHIL identified 93% and 86% complete occlusion rates, respectively. The overall procedure-related permanent morbidity rate was 3% for dAVFs and 7% for cAVMs. There was only one procedure-related mortality, which developed in a cAVM case, across 214 cases.

CONCLUSION

Squid and PHIL are safe and effective embolic agents for treatment of dAVFs and cAVMs.

Endovascular treatment of intracranial dural arteriovenous fistulas with Onyx: A consecutive series of 62 patients from a single-center

OBJECTIVE

Intracranial intracranial dural arteriovenous fistulas (DAVFs) are mainly treated with an endovascular approach and various embolic agents. The aim of this study was to investigate the efficacy and safety of Onyx embolization in the treatment of DAVFs and characterize the factors as sociated with complete obliteration.

METHODS

This retrospective study was based on 62 patients with DAVFs who underwent endovascular treatment with Onyx alone or in combination with coils at our institution. Clinical and imaging data were collected and analyzed.

RESULTS

A total of 62 patients with 64 DAVFs were treated with endovascular embolization. The most common primary symptom was ophthalmological signs with a rate of 37.1%. Cognard type III was the most commonly seen subtype (32.8%). The immediate complete occlusion and follow-up rate was 92.2% and 93.5%, respectively. Transvenous balloon-assisted sinus protection was used in 12 patients (18.8%). The pressure cooker technique was used in eight patients (12.5%). Complications were seen in five patients including intracerebral hemorrhage (n = 2), venous thrombotic events (n = 2), and glued microcatheter (n = 1).

CONCLUSIONS

Endovascular Onyx alone or in combination with coils embolization is a safe and effective therapy for DAVFs. Favorable angiographic and clinical outcomes can be achieved using different endovascular approaches. Transvenous balloon-assisted sinus protection and the pressure cooker technique may help achieve complete occlusion of DAVFs.

Traumatic middle meningeal arteriovenous fistulas (MMAVFs): an exploratory systematic review

This study aims to systematically review case reports and case series in order to compare the postoperative course of conservative, endovascular and surgical treatments for traumatic dural arteriovenous fistulas predominantly supplied by the middle meningeal artery (MMAVFs), which usually occur following head trauma or iatrogenic causes. We conducted a comprehensive search of PubMed, Embase, Scopus, Web of Science, and Google Scholar until June 23rd, 2024. Three cohorts were defined based on the treatment modality employed. The primary outcomes were the rates of overall obliteration and postoperative complications, with all-cause mortlality considered as secondary outcome. A total of 61 studies encompassing 78 pooled MMAVFs were included in the qualitative analysis. The predominant demographic consisted of males (53.9%) with a median age of 50.5 (IQR: 33.5-67.5) years. The main etiologies for fistula formation were head trauma (75.6%), cranial neurosurgical procedures (11.5%) and endovascular embolization (8.97%). Venous drainage patterns were categorized as follows based on anatomical confluence: Class I (16.7%), II (14.1%), III (12.8%), IV (14.1%), V (7.7%), and VI (3.9%). Regarding treatment efficacy, the overall obliteration rate was 89.74%, achieved through endovascular (95.83%), surgical (64.29%) or conservative (93.75%) approaches. In terms of safety, the overall postoperative complication rate was 6.49% with an all-cause mortality rate of 8.97%, predominantly observed in the surgical group (35.71%). Our systematic review highlights the challenging management of traumatic MMAVFs, frequently associated with head injuries. Endovascular therapy has emerged as the predominant treatment modality, demonstrating markedly higher rates of fistula obliteration, reduced all-cause mortality, and fewer postoperative complications.

Preoperative Direct Puncture Embolization of Castleman Disease of the Parotid Gland: A Case Report

BACKGROUND

Castleman disease (CD) is an uncommon benign lymphoproliferative disease characterized by hypervascular lymphoid hyperplasia. We present a unique case of unicentric CD of the parotid gland treated by preoperative direct puncture embolization.

CASE PRESENTATION

A 27-year-old female patient was admitted for a right neck mass. Ultrasound examination and MRI scan documented a hypervascular mass within the right parotid gland. Preoperative embolization was performed by direct puncture technique: a needle was inserted into the core of the mass under both ultrasound and fluoroscopic guidance and SQUID 12 was injected into the mass under fluoroscopic control, achieving a total devascularization.

CONCLUSION

Preoperative direct puncture embolization was safe and effective and provides excellent hemostatic control during the surgical operation, limiting the amount of intraoperative bleeding.

LIQUID - Treatment of high-grade dural arteriovenous fistulas with Squid liquid embolic agent: a prospective, observational multicenter study

BACKGROUND

Endovascular embolization is a feasible treatment for cranial dural arteriovenous fistulas (DAVFs). New embolic agents aim to improve the success of DAVF embolization.

OBJECTIVE

To assess the safety, efficacy, and short-term outcome of the treatment of DAVFs using the new liquid embolic agent Squid.

METHODS

The LIQUID study is a prospective, observational multicenter study on the treatment of high-grade (Cognard type ≥3) DAVFs with the embolic agent Squid. The primary outcome measures were safety (ie, morbidity and mortality), as well as the occlusion rate 90 to 180 days after treatment.

RESULTS

In eight centers, 53 patients (mean age 59.8 years, 22.6% female) were treated in 55 treatment sessions. Of the DAVFs, 56.6% were Cognard type III, 41.5% type IV, and 18.9% were ruptured. Squid 18 was used in 83.6% and Squid 12 in 32.7% of the treatments. The overall rate of intraprocedural or postprocedural adverse events (AEs) was 18.2%. Procedure-related AEs resulting in permanent morbidity were observed in 3.6%. One patient (1.8%) died unrelated to the procedure due to pulmonary embolism. The final complete occlusion rate at 90 to 180 days was 93.2%. After a mean follow-up of 5.5 months, the modified Rankin Scale (mRS) score was stable or improved in 93.0%. In one of the patients, worsening of the mRS score was related to the procedure (1.8%).

CONCLUSION

Squid is a safe and effective liquid embolic agent for the treatment of high-grade DAVFs.

Embolization of brain arteriovenous malformations with squid co-polymer embolic material: Initial experience

Objective

To analyze the safety and effectiveness of the ethylene-vinyl alcohol copolymer (EVOH) liquid embolic agent Squid (Emboflu, Switzerland) for the treatment of brain arteriovenous malformations.

Materials and procedures

Between April 2015 and July 2017, 46 embolization treatments for brain arteriovenous malformations (BAVM) were performed in 25 patients using two Squid formulations (18 and 12). Six female and 19 male patients with a mean age of 34 years (range, 9-62 years) were included. A total of 46 procedures were performed. The BAVMs were classified as Spetzler-Martin grade II in 4 procedures, III in 27 procedures, and 1V in 15 procedures. Among the 25 patients, 15 presented with hemorrhage, 5 with seizures, and 5 with headache and neurology. The BAVMs were located in the temporal lobe in 5 patients, parietal lobe in 7 patients, frontal lobe in 3 patients, posterior fossa in 6 patients, basal ganglia in 3 patients, and parasagittal lobe in 1 patient.

Results

The obliteration rate of the BAVMs ranged from 10% to 100%, with a mean of 33%. Most patients underwent their first or second embolization procedure. Four patients (8%) developed intracranial bleeding post-procedure, with one death (2%). One patient (2%) experienced a seizure during the procedure; however, no intracranial bleeding was observed. Seven patients (15%) experienced perforations during catheter manipulation. One case (2%) of a fractured catheter was recorded, but no significant complications were observed. The average volume of copolymer injected was 0.6 ​ml per nidus. Thirteen procedures used the Squid-12 formulation, 29 procedures used the Squid-18 formulation, and 3 procedures used a combination of Squid-12 and -18 formulations.

Conclusion

Squid is a safe and effective embolic agent for treating BAVMs.

Liquid Embolic Agents for Endovascular Embolization: A Review

Endovascular embolization (EE) has been used for the treatment of blood vessel abnormalities, including aneurysms, AVMs, tumors, etc. The aim of this process is to occlude the affected vessel using biocompatible embolic agents. Two types of embolic agents, solid and liquid, are used for endovascular embolization. Liquid embolic agents are usually injectable and delivered into the vascular malformation sites using a catheter guided by X-ray imaging (i.e., angiography). After injection, the liquid embolic agent transforms into a solid implant in situ based on a variety of mechanisms, including polymerization, precipitation, and cross-linking, through ionic or thermal process. Until now, several polymers have been designed successfully for the development of liquid embolic agents. Both natural and synthetic polymers have been used for this purpose. In this review, we discuss embolization procedures with liquid embolic agents in different clinical applications, as well as in pre-clinical research studies.

Middle Meningeal Artery Embolization for the Management of Chronic Subdural Hematomas: A New-Old Treatment

Chronic subdural hematoma (cSDH) is defined as a subdural collection of blood on CT imaging that tends to persist and gradually increase in volume over time, with components that are hypodense or isodense compared to the brain. There are no proven guidelines for the management of patients with cSDH. Surgical approaches included burr hole, twist drill hole, and craniotomy-based evacuations. Outcomes after surgical removal is generally favorable, but cSDH tends to recur after the initial evacuation.Middle meningeal artery (MMA) embolization has been gaining increasing popularity among the treatments of cSDH. This is largely due to a growing population of patients with cSDH who are refractory to other treatments or in patients who present with multiple comorbidities or who are taking antiplatelet and anticoagulant medications. The goal of middle meningeal artery (MMA) embolization is to devascularize subdural membranes associated with SDH so that the balance between continued leakage and reabsorption is shifted toward reabsorption.We discuss our clinical and technical approach to cSDH treated with perioperative embolization of the MMA.

Hybrid operation for arteriovenous malformations with associated multiple intracranial aneurysms and subarachnoid hemorrhage: Case report

RATIONALE

The hybrid surgical concept for the treatment of brain arteriovenous malformations (AVMs) with associated intracranial aneurysms (IAs) is still not widely practiced. Concomitant occurrence of AVMs with IAs is common. Subarachnoid hemorrhage (SAH) as a result of AVM or IA rupture is often associated with these dual pathological phenomena. We present a case of concomitant occurrence of AVMs and IAs that was successfully treated using the hybrid operation concept.

PATIENT CONCERNS

A 62-year-old man presented with sudden onset of severe headache, dizziness, nausea, and vomiting for 4 hours.

DIAGNOSIS

Computed tomography revealed SAH and a hematoma in the right frontal lobe. A computed tomographic angiogram also revealed a right frontal AVM with 3 IAs.

INTERVENTIONS

We used a hybrid operating room to successfully treat both AVMs and IAs.

OUTCOMES

Two years of follow-up showed that the patients were well and performed their daily duties.

LESSONS

The hybrid operating room is an innovative, safe, and effective method for the treatment of AVMs with associated IAs, particularly high-grade AVMs and IAs with hemorrhage or SAH. Patients with concomitant AVMs and IAs have the highest chance of hemorrhage compared with those with AVM or IAs alone.

Embolic Materials: Understanding the Ocean of Choices

Embolization is a fundamental procedure that interventional radiologists perform on a daily basis to treat a variety of diseases. The disease processes for which embolization is considered a safe and effective treatment are continuously expanding, as are the embolization materials available for use. To achieve optimal clinical outcomes and minimize complications, it is imperative that the interventional radiologist understands the properties, strengths, and weaknesses of each class of embolic and specific embolic products. This is a continuous process as new materials are always becoming available. This article reviews the different classes of embolic materials, discusses strengths and weaknesses, and reviews areas of innovation.

The Common but Complicated Tool: Review of Embolic Materials for the Interventional Radiologist

Embolization is an important and widely utilized technique in interventional radiology. There are a variety of different categories and individual products which can be utilized to perform embolization. Understanding the different classes of embolic agents, the important features of each of these classes including strengths and limitations, and the variation in individual products within the classes is critical for interventional radiologist to practice safely and effectively. This article reviews the different kinds of embolics and relays some of the pertinent physical and chemical properties of individual products which should be considered when determining which embolic to select for a given purpose.

Glue, Onyx, Squid or PHIL? Liquid Embolic Agents for the Embolization of Cerebral Arteriovenous Malformations and Dural Arteriovenous Fistulas

Background

Endovascular embolization is an effective treatment option for cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). A variety of liquid embolic agents have been and are currently used for embolization of AVMs and DAVFs. Knowledge of the special properties of the agent which is used is crucial for an effective and safe embolization procedure.

Material and Methods

This article describes the properties and indications of the liquid embolic agents which are currently available: cyanoacrylates (also called glues), and the copolymers Onyx, Squid and PHIL, as well as their respective subtypes.

Results

Cyanoacrylates were the predominantly used agents in the 1980s and 1990s. They are currently still used in specific situations, for example for the occlusion of macro-shunts, for the pressure cooker technique or in cases in which microcatheters are used that are not compatible with dimethyl-sulfoxide. The first broadly used copolymer-based embolic agent Onyx benefits from a large amount of available experience and data, which demonstrated its safety and efficacy in the treatment of cerebral vascular malformations, while its drawbacks include temporary loss of visibility during longer injections and artifacts in cross-sectional imaging. The more recently introduced agents Squid and PHIL aim to overcome these shortcomings and to improve the success rate of endovascular embolization. Novelties of these newer agents with potential advantages include extra-low viscosity versions, more stable visibility, and a lower degree of imaging artifacts.

Conclusion

All the available liquid embolic agents feature specific potential advantages and disadvantages over each other. The choice of the most appropriate embolic agent must be made based on the specific material characteristics of the agent, related to the specific anatomical characteristics of the target pathology.

Visceral Artery Aneurysms Embolization and Other Interventional Options: State of the Art and New Perspectives

Visceral artery aneurysms (VAAs) are rare, usually asymptomatic and incidentally discovered during a routine radiological examination. Shared guidelines suggest their treatment in the following conditions: VAAs with diameter larger than 2 cm, or 3 times exceeding the target artery; VAAs with a progressive growth of at least 0.5 cm per year; symptomatic or ruptured VAAs. Endovascular treatment, less burdened by morbidity and mortality than surgery, is generally the preferred option. Selection of the best strategy depends on the visceral artery involved, aneurysm characteristics, the clinical scenario and the operator's experience. Tortuosity of VAAs almost always makes embolization the only technically feasible option. The present narrative review reports state of the art and new perspectives on the main endovascular and other interventional options in the treatment of VAAs. Embolization techniques and materials, use of covered and flow-diverting stents and percutaneous approaches are accurately analyzed based on the current literature. Visceral artery-related considerations and targeted approaches are also provided and discussed.

Facial palsy after embolization with Squid® 12

Endovascular procedures with liquid embolic agents such as ethylene-vinyl alcohol (EVOH) copolymers are indicated before surgical treatment of cervical paraganglioma. Consequently, these agents are now available as low viscosity formulations, one of which is Squid 12, which are demonstrating superior vascular penetration. Cases of facial paralysis secondary to embolization of cervical vascular lesions with classic embolic agents have been reported in the English literature, however, this complication has not been described with new generation options such as Squid 12.

We describe the case of a 43-year-old patient with a left neck carotid paraganglioma. Embolization was performed under general anaesthesia before surgical excision. In the immediate postoperative period, the patient developed total left facial palsy. Since the imaging tests (Computed Tomography (CT) and Magnetic Resonance Imaging (MRI)) and neurological examination showed no involvement of additional cranial nerves (CN), we hypothesise that the main cause of this complication is ischemia of the vasa nervorum of CN VII secondary to embolization. Almost six months later, the patient continues to present total facial paralysis (Grade VI House-Brackmann facial paralysis scale), and palsy of the left CN X and XII as a complication secondary to surgical resection of the paraganglioma.

This case is relevant since it is the first clinical case of permanent facial paralysis secondary to embolization with Squid 12.

Emergency tips recanalisation and gastroesophageal varices embolisation with an ethylene vinyl alcohol copolymer agent (Squid) and detachable coils

Transjugular intrahepatic portosystemic shunt (TIPS) is currently indicated as first therapeutic option in the main complications of portal hypertension, including bleeding gastroesophageal varices and refractory ascites. In case of bleeding gastroesophageal varices, an adjuvant embolisation within TIPS can be useful to prevent rebleeding. In the present technical note, the management in emergency of a patient with haemorrhagic shock due to bleeding gastroesophageal varices and occluded TIPS is reported. TIPS recanalisation with an adjunctive stent and high-pressure balloon angioplasty and gastroesophageal varices embolisation using detachable coils and a non-adhesive liquid embolic agent were performed during the same emergent procedure. After the procedure, clinical stabilisation of the patient was achieved, with blood transfusions suspension and Blakemore tube removal. At 6 months, regular TIPS patency at colour Doppler and no rebleeding episodes were recorded. To our knowledge, whilst coils are routinely used for varices embolisation, non-adhesive liquid embolic agents have been never mentioned. Liquid embolic agents seem to provide a stable plug strengthening the embolising action of the coils. Further studies involving a cohort of patients with long-term follow-up will be necessary to confirm whether this association can be more effective than coils alone in gastroesophageal varices embolisation.