Transarterial coil-augmented Onyx embolization for brain arteriovenous malformation. Technique and experience in 22 consecutive patients

Pediatric Cerebral Vascular Malformations : Current and Future Perspectives

Intracranial vascular malformations typically encountered by pediatric neurosurgeons include arteriovenous malformations, vein of Galen malformations and cavernous malformations. While these remain amongst some of the most challenging lesions faced by patients and caregivers, the past decade has produced marked advances in the understanding of the pathophysiology of these conditions, with concomitant innovations in treatment. This article will highlight present and future perspectives relevant to these diseases, with a focus on an emerging approach utilizing disease-specific mutations to develop a novel taxonomy for these conditions.

Evolution of clinical and translational advances in the management of pediatric arteriovenous malformations

Arteriovenous malformations (AVMs) represent one of the most challenging diagnoses in pediatric neurosurgery. Until recently, the majority of AVMs was only identified after hemorrhage and primarily treated with surgery. However, recent advances in a wide range of fields-imaging, surgery, interventional radiology, radiation therapy, and molecular biology-have profoundly advanced the understanding and therapy of these complex lesions. Here we review the progress made in pediatric AVMs with a specific focus on innovations relevant to clinical care.

Chimney Graft Technique Combined With Embolization for Treating Ruptured Aortic Arch Lesions

Background: This study aimed to share the experience in applying the chimney graft technique combined with embolization for treating aortic arch rupture under emergency conditions and evaluating early-term results in these patients. Methods: This study retrospectively included patients with ruptured aortic arch lesions who received the chimney graft technique combined with embolization between March 2016 and March 2021. The primary endpoint was a technical success, deemed as successful stent graft deployment to the planned location, patency of the target branch vessel, and absence of significant type I endoleak. The secondary endpoint was clinical success defined with the size of false lumen in follow-up remaining unchanged or decreasing over time, 30-day mortality, complication, and primary patency of chimney graft. Results: This study included 12 patients (age, 61 ± 12 years; male, 83%). Five patients (42%) received single chimney, one patient (8%) received double chimney, and six patients (50%) received triple chimney. Intraoperative type I endoleak occurred in six patients (50%) who underwent endovascular embolization in the primary operation. Post-operative type I endoleak, evaluated by computed tomography angiography examination following the primary operation, occurred in seven patients (58%), including one patient who received endovascular embolization two times. All patients with post-operative type I endoleak were successfully re-treated using coil and Onyx glue within 1 week, and the median length of stay was 22 ± 11 days (range: 7-44 days). Overall technical success was 100%. Eleven patients had completed their follow-up (median, 12 months, range: 1-34 months), and one patient was out of contact. The 30-day mortality was 9% (1/11, post-operative death of a patient with cerebral hemorrhage). No major complications and no chimney compression, migration, occlusion, or stenosis were recorded during follow-up. Seven patients (58%) have ≥6 months of clinical follow-up time with appropriate imaging. In four (57%) of these patients, diameter stabilization was detected, whereas three (43%) experienced significant reduction (≥5 mm). Conclusion: The patients in this study had satisfactory early-term outcomes. The chimney graft technique combined with coil and Onyx glue embolization may be a safe and effective treatment for ruptured aortic arch lesions under emergency conditions.

Patterns of Failure After Linear Accelerator Radiosurgery for Cerebral Arteriovenous Malformations

BACKGROUND

Numerous studies have assessed the predictive factors for the arteriovenous malformation (AVM) response to stereotactic radiosurgery (SRS). However, only a few have discussed the causes of failure. The aim of the present study was to evaluate the patterns of failure in patients with AVM who had undergone linear accelerator SRS.

METHODS

We performed a retrospective analysis of 288 patients who had undergone linear accelerator SRS in our institution from 1995 to 2011. Failure was defined from the findings of the follow-up angiogram at 5 years, with failure identified in 44 patients. The distribution of causes was estimated using a descriptive analysis of literature-based causes, including a minimal margin dose of <18 Gy, a residual nidus outside the initial targeted volume, previous embolization, recanalization, and the size of the target volume. We also analyzed the associations among the causes.

RESULTS

Incomplete nidus identification (41%) and previous embolization (77%) were the most frequently observed conditions in patients with failure. Patients who had undergone previous embolization, for whom the cause of failure had always been identified (P = 0.001), were younger (P = 0.004) and had had a larger nidus volume (P = 0.025). Recanalization was rare (5 of 34 patients) and had occurred exclusively in women (P = 0.048). Larger nidus volumes were less frequent (mean, 2.18 ± 2.2 cm³; range, 0.13-10.8 cm³) and had been observed mainly in women when >2 cm³ (P = 0.012). An insufficient dose was observed in 9 patients and had occurred in the case of a larger volume (P = 0.031), which had resulted in dosimetry constraints in 3 patients and treatment in the vicinity of eloquent zones in 6 patients. No known cause was found in 5 patients, 4 of whom had had a low Spetzler-Martin grade (I and II; P = 0.003), suggestive of radioresistance.

CONCLUSION

The results of our detailed analysis have highlighted the distribution of the causes of failure and the potential role of radioresistance in treatment failure.

Initial experience with the new ethylene vinyl alcohol copolymer based liquid embolic agent Menox in the endovascular treatment of cerebral arteriovenous malformations

Background and Purpose

Liquid embolic agents (LEAs) are the determinant tool for successful embolization of cranial arteriovenous shunts. There are few currently available LEAs. The aim of the study was to summarize our initial experience with a recently introduced non-adhesive ethylene vinyl alcohol (EVOH) copolymer based LEA (Menox 18) in the endovascular treatment of cerebral arteriovenous malformations.

Methods

From April 2018 to November 2018, 24 patients harboring cerebral arteriovenous malformations underwent endovascular embolization with Menox 18. Clinical features, angiographic results, procedural details, complications, and follow-up details were prospectively collected and retrospectively analyzed.

Results

Curative embolization in one endovascular session was achieved in 14/24 (58.3%) of the treated patients. Partial embolization was achieved in 10 patients (42.6%) in whom staged treatment with radiosurgery or microsurgical resection was planned. No mortality was recorded in our series. Clinical complications after embolization occurred in 1/24 (4.66%) patients. No technical complications were noted

Conclusions

Our pilot study suggests that the Menox embolization system offers similar technical and clinical results in comparison with the other currently available LEAs. Further studies with larger cohorts and long term follow-up data are needed to fully evaluate its efficacy

Traumatic arteriovenous fistula between the extracranial middle meningeal artery and the pterygoid plexus: A case report and literature review

The formation of a traumatic arteriovenous fistula (AVF) between the extracranial middle meningeal artery (MMA) and the pterygoid plexus (PP) is very rare, and understanding of this condition is limited. This paper reports the case of an 8-year-old who suffered minor injuries after a high fall four months prior to admission and showed good recovery after one month. However, the child gradually developed exophthalmos of the left eye and conjunctival redness one month prior to admission. Auscultation revealed an intracranial murmur near the left side of the face, in the temporal region. A digital subtraction angiography (DSA) showed rupture of the left extracranial MMA and an AVF between the MMA and the PP. The blood drained toward the cavernous sinus, resulting in retrograde blood flow into the ophthalmic vein and the cortical vein. The diagnosis was an AVF between the MMA and the PP, and a combination of coils and Onyx liquid embolic agent was employed to perform AVF embolization. Follow-up six months later indicated no recurrence of the AVF, and the patient showed good recovery with a normal-appearing left eye. The AVF in this case drained toward the cavernous sinus, and symptoms of increased intracranial venous system pressure were apparent, similar to those produced by fistulas between the internal carotid artery and the cavernous sinus. This condition is very rare, and the use of coils in combination with Onyx for AVF embolization is novel, warranting the reporting of the current case.

Prioritized Venous Coiling Facilitating Endovascular Treatment of Brain Arteriovenous Malformations with a Fistulous Component

BACKGROUND

Brain arteriovenous malformation (AVM) with a fistulous component presents a treatment challenge. The presence of the fistulous component may be related to either a complication from endovascular treatment, perioperative hemorrhagic events during surgical resection, or incomplete obliteration after radiosurgery.

CASE DESCRIPTION

From December 2010 to May 2014, 7 consecutive patients (3 men, 4 women, average age, 28.7 years; age range, 11 months to 67 years) with AVMs with a high-flow fistulous component were treated at our institute with venous coiling before transarterial liquid embolization. One AVM was grade I based on the Spetzler-Martin grading system, 1 was grade II, 3 were grade III, and 2 were grade IV. The nidus size ranged from 1.7 to 6.0 cm. Four patients had pure fistulous-type lesions, and 3 had lesions of the mixed fistulous-plexiform type. All AVMs shared a common feature of a high-flow fistulous component with a large venous pouch emerging from the nidus. After endovascular embolization of the AVMs, 3 patients had complete occlusion, 3 patients had near-complete occlusion, and 1 patient had significant reduction in volume. There was no immediate complication after embolization, but 1 patient experienced delayed hemorrhage 3 days after the procedure.

CONCLUSIONS

Prioritized transarterial venous coiling is feasible for the embolization of AVMs with a high-flow fistulous component and the procedure had an acceptable complication rate.