Effect of coil packing proximal to the dilated segment on postoperative medullary infarction and prognosis following internal trapping for ruptured vertebral artery dissection

Ruptured thrombosed vertebral artery dissecting aneurysm treated with staged flow diverter after prediction of the rupture point by vessel wall MRI

The safety and feasibility of using staged flow diverter (FD) for ruptured cerebral aneurysms, in which coil embolization is performed in the acute phase and FD is deployed in the subacute phase, has recently been reported. This strategy requires assuming the rupture point and performing coil embolization. Although vessel wall magnetic resonance imaging (VW-MRI) has been reported to be useful in predicting the rupture point of aneurysms, its use with staged FD has not yet been reported. We report the first case of staged FD with preoperative contrast-enhanced VW-MRI to predict the rupture point for partially thrombosed vertebral artery dissecting large aneurysm involving posterior inferior cerebellar artery (PICA) origin. This approach achieved a very good outcome, not only completely occluding the aneurysm, but also reconstructing the parent artery while maintaining the patency of the PICA.

Efficacy and predicting factors of multimodal treatment for ruptured intracranial vertebral artery dissecting aneurysms

We aimed to investigate the efficacy of our multimodal strategies and propose a treatment algorithm for ruptured vertebral artery dissecting aneurysms (VADAs). This study included 41 patients treated at a single institution between 2015 and 2022. The treatment modalities were justified based on the collateral circulation and aneurysm location related to the posterior inferior cerebellar artery (PICA). Treatment outcomes and complications of each treatment group were analyzed. The association between the collateral blood flow and the postoperative vertebrobasilar ischemia (VBI) was also investigated. There were 17 post-PICA, 10 PICA-involved, 7 pre-PICA, and 7 non-PICA types. Reconstruction techniques included flow diversion devices (n = 11) and stent-assisted coiling (n = 3). Deconstruction techniques included coil trapping (n=17) and microsurgical parent artery occlusion with (n = 8) or without PICA revascularization (n = 2). Five (18.5%) of the deconstruction group had postoperative VBI. Overall favorable outcomes in both groups were observed in 70.7% of patients with a mean follow-up time of 21.5 months. Poor World Federation of Neurosurgical Societies grade (IV-V) was identified as a predictor of unfavorable outcomes (p = 0.003). In addition, the VA4/BA4 ratio > 0.22, the presence of collateral blood flow from the posterior communicating artery (PcomA), and a contralateral VA diameter > 2.5 mm were associated with a lower risk of postoperative VBI. In summary, the proposed strategic treatment in this study is pragmatic, yielding satisfactory results where a deconstructive technique should be used with caution, particularly when there is a flow mismatch or the absence of collateral PcomA in the vertebrobasilar circulation.

Single-Center Case Series of Simple Proximal Clipping for Large Thrombosed Vertebral Artery Aneurysms: Preservation of Perforating Arteries and Long-Term Outcomes

BACKGROUND

Surgical proximal parent artery occlusion (PAO) is one of the treatments for partially thrombosed vertebral artery aneurysms (PTVAs). However, whether long-term changes in size and perforating arteries through the blind end can be truly preserved remain unknown.

OBJECTIVE

To evaluate the efficacy and safety of surgical proximal PAO for PTVAs, focusing on the transition in size and preservation of perforating arteries.

METHODS

We retrospectively reviewed 14 consecutive cases of unruptured large PTVAs. The cases were treated with surgical proximal PAO without trapping or thrombectomy. Preservation of the perforating arteries was confirmed through intraoperative indocyanine green video angiography. The aneurysm size was evaluated by measuring the maximum diameter on axial T2-weighted magnetic resonance images. Post-treatment outcomes were assessed using the modified Rankin Scale at the last follow-up examination.

RESULTS

Thirteen patients (excluding 1 with morbidity) had a mean follow-up time of 33.2 months (range, 12-60 months) and a mean reduction rate of 71% (range, 32%-95%). Only 1 patient (7.2%) experienced postoperative stroke, and 13 patients (92.8%) showed no worsening of the modified Rankin Scale score at the final follow-up examination. The symptoms were improved in 5 of the 6 symptomatic patients (83.3%). In 10 patients (71.4%), a perforating branch that could not be identified on preoperative imaging was identified intraoperatively.

CONCLUSION

Surgical proximal PAO without trapping or thrombectomy for PTVAs allows long-term reduction of aneurysm size and improves treatment safety by preserving the perforating artery, especially in cases wherein direct reconstruction is not feasible.

Internal Trapping of an Acutely Ruptured Dissecting Aneurysm of a Dominant Vertebral Artery Following Balloon Test Occlusion: A Case Report

Objective

To report a case of an acutely ruptured vertebral artery dissecting aneurysm (VADA) with a hypoplastic contralateral vertebral artery (VA) successfully treated with internal trapping following the estimation of the collateral flow from anterior circulation.

Case Presentation

A 46-year-old woman was diagnosed with subarachnoid hemorrhage and acute hydrocephalus. Ventriculostomy was performed under general anesthesia. CTA revealed a left VADA distal to the origin of the left posterior inferior cerebellar artery (PICA). The right VA was hypoplastic, and the right posterior communicating artery (Pcom) was fetal type. We performed balloon test occlusion (BTO) of the VA proximal to the origin of the left PICA and estimated sufficient collateral blood flow via the right Pcom and basilar artery (BA) to the anterior spinal artery (ASA) and the left PICA. Internal trapping of the left VADA was then performed. The angiograms after internal trapping revealed collateral flow from the right Pcom to the BA, and the hypoplastic right VA perfused the proximal BA and ASA. She recovered without any neurological deficits following antiplatelet therapy and vasospasm treatment. She was followed up for 6 years without any neurological events occurring.

Conclusion

When BTO indicates sufficient collateral flow, internal trapping could be a useful treatment for acutely ruptured VADAs on the dominant side, given a complete understanding of the angioarchitecture and the risk of vasospasm due to subarachnoid hemorrhage.

Complex Intracranial Aneurysms

Complex intracranial aneurysms remain challenging to treat using standard microsurgical or endovascular techniques. These aneurysms often require a combination of deconstructive and reconstructive procedures, such as parent artery occlusion, flow alteration, and blind-alley formation with or without bypass surgery, for effective and enduring therapeutic effects. It is important to determine the type of bypass based on the site of occlusion of the patent artery, anatomical features of the distal vessels, and expected adequate blood flow. In this chapter, we describe the "Standards," "Advances," and "Controversies" in the context of a microsurgical treatment strategy for complex intracranial aneurysms. "Standards" include a combination of frequent and commonly used procedures that have been gathering a certain consensus on their effectiveness. "Advances" include infrequent, demanding, and/or uncertain surgical procedures that are currently under debate. Finally, "Controversies" discuss a number of unsolved issues.

Mobile endovascular therapy for acute treatment of ruptured vertebral artery dissecting aneurysm in multiple hospitals

BACKGROUND

The patients with ruptured vertebral artery dissecting aneurysm (rVADA) should be treated as early as possible because VADA carries extremely high risk of rebleeding in the acute phase. We have established a mobile endovascular strategy for the patients with rVADA between our flagship center and its affiliated local hospitals. We introduced and reviewed our mobile endovascular therapy in this study.

METHODS

We retrospectively evaluated 98 consecutive patients who underwent endovascular surgery for rVADA from 2000 to 2018 at our institution or five affiliated hospitals. When each patient was initially transported to the local affiliated hospitals, neuroendovascular surgeons traveled directly to the affiliated hospital from the flagship center in order to treat the patient there. Clinical outcomes using modified Rankin Scale at 6 months after treatment, radiological results, and procedure-related complications were reviewed to justify our mobile endovascular strategy.

RESULTS

All aneurysms were cured successfully by internal trapping. Favorable outcome was achieved in 61 patients (62.2%) even though 53 patients (54.1%) had presented with severe subarachnoid hemorrhage. Overall mortality rate, treatment-related mortality rate, and treatment related complication rate were 18.4% (18/98), 0%, and 16% (16/98), respectively. There were no differences in clinical and radiological outcomes between the patients treated in the flagship center and those who treated in the affiliated hospitals. Treatment in the affiliated hospital was not a predictive factor of unfavorable outcome in our multivariate analysis, and elderly age (≥ 60) was negatively associated with favorable outcome.

CONCLUSIONS

Our results prove the efficacy and safety of mobile endovascular therapy for the treatment of rVADA in the ultra-acute stage. Mobile endovascular therapy may work well in the acute treatment of rVADAs in the certain circumstance.

Risk factors for medullary infarction after endovascular trapping of vertebral artery dissecting aneurysms

Internal trapping (IT) is a treatment option for intracranial vertebral artery dissecting aneurysms (VADAs). Medullary infarction (MI) is a complication linked to this treatment. This study aims to clarify the outcomes of IT for VADAs and the risk factors for MIs. We retrospectively reviewed the databases from 2010 to 2017 to identify patients with VADAs treated by IT at seven collaborating institutions. Radiological findings, clinical courses, and outcomes were analyzed. Perforating arteries were classified into terminal or longitudinal types using preoperative angiography. IT was completed in 90 patients (74 ruptured and 16 unruptured VADA). Postoperative rebleeding did not occur in any ruptured VADA patients. Postoperative MRI detected MIs in 26 patients (28.9%). The incidence of MIs in the ruptured VADA (32%) was higher compared with that in the unruptured VADA (13%), though it was not significant. In the MI group, the occlusion or blind alley of the terminal-type and longitudinal-type perforator was confirmed in 23 patients (88%) and 11 patients (42%), respectively. The occlusion or blind alley of the terminal-type perforator was an independent risk factor for MIs in the logistic regression analysis (OR 5.81; 95% CI 1.34-25.11; p = 0.018). In ruptured VADA, postoperative MI (OR 12.2; 95% CI 3.19-64.55; p = 0.0001) and high-grade SAH (OR 8.02; 95% CI 2.32-37.70; p = 0.0006) were independent risk factors of an unfavorable clinical outcome. In conclusion, MIs were an independent risk factor for unfavorable outcomes after IT, especially for a ruptured VADA. The occlusion or blind alley of the terminal-type perforator caused by the IT was associated with postoperative MIs.

Delineability and anatomical variations of perforating arteries from normal vertebral artery on 3D DSA: implications for endovascular treatment of dissecting aneurysms

BACKGROUND AND PURPOSE

Endovascular trapping of the vertebral artery dissecting aneurysms (VADAs) carries a risk of medullary infarction due to the occlusion of the perforating arteries. We evaluated the detectability and anatomical variations of perforating arteries arising from the vertebral artery (VA) using three-dimensional DSA.

METHODS

In 120 patients without VA lesions who underwent rotational vertebral arteriography, the anatomical configurations of perforating arteries from the VA were retrospectively evaluated on the bi-plane DSA and reconstructed images to reach the consensus between two experienced reviewers. The images were interpreted by focusing on the numbers and types of perforating arteries, the relationships between the number of perforators and the anatomy of the VA and its branches.

RESULTS

Zero, 1, 2, 3, 4, and 6 perforators were detected in 2, 51, 56, 9, 1, and 1 patient, respectively (median of 2 perforators per VA). The 200 perforators were classified into 146 terminal and 54 longitudinal course types and into 32 ventral, 151 lateral, and 17 dorsolateral distribution types. All ventral type perforators were also terminal type. In contrast, the longitudinal type was seen in 28.5% of lateral types and in 65% of dorsolateral types. Regarding the difference in the origin of the posterior inferior cerebellar artery (PICA), non-PICA type VAs gave off larger number of perforators than the other types of VAs.

CONCLUSIONS

Non-PICA type VAs give off a significantly larger number of perforators than other types, indicating that the trapping of non-PICA type VAs is associated with a risk of ischemic complications.

Dissection of the Vertebral Artery Fenestration Limb Presenting with Occlusion After Rupture

BACKGROUND

Dissection of a vertebral artery (VA) fenestration is extremely rare. We herein present the first case of a patient who presented with the dissection of a VA fenestration limb accompanied by occlusion after rupture, who was treated with internal trapping of the dissected limb and the parent artery proximal to the fenestration.

CASE DESCRIPTION

A 55-year-old man presented with sudden headache and altered consciousness. Computed tomography at admission showed subarachnoid hemorrhage. Angiography showed occlusion of the inner limb of the vertebrobasilar junction fenestration, and the occluded ends had a tapered shape, suggesting the occlusion of the dissection of the inner limb after rupture. Angiography immediately before embolization revealed inner limb recanalization with an irregular string sign; thus only the inner limb was embolized. Angiography after embolization showed near-complete suppression of the blood flow in the inner limb; however, a slight antegrade flow through the coil mass was observed in the late phase. The procedure was finished with the expectation of complete occlusion over time with natural heparin reversal. Angiography 8 days after embolization revealed a significant increase in antegrade blood flow through the coil mass within the inner limb. Therefore additional embolization of the parent artery proximal to the fenestration was performed, which achieved complete occlusion.

CONCLUSIONS

The embolization length was limited and the antegrade blood flow through the other limb remained during internal trapping for the dissected VA fenestration limb; therefore careful observation of the blood flow to the dissected segment after embolization is necessary.

Predictive factors of medullary infarction after endovascular internal trapping using coils for vertebral artery dissecting aneurysms

OBJECTIVE The first choice of treatment in cases of vertebral artery dissecting aneurysms (VADAs) is endovascular internal trapping (EIT) of the dissecting segment using coils. However, this procedure carries the risk of medullary infarction, and the risk factors for this complication are not well understood. This study investigated the risk factors causing medullary infarction. METHODS One hundred patients who underwent EIT for VADAs were included in this study. Ninety-three patients presented with subarachnoid hemorrhage. In cases involving the posterior inferior cerebellar artery (PICA), partial internal trapping targeting the ruptured site was performed to preserve the PICA. The VADAs were classified into the distal VA stump group, proximal VA stump group, and entire VA stump group, according to the location of VA segments without adequate flow-out vessels (such as the PICA [VA stump]) at risk of delayed thrombosis. The occurrence of medullary infarction was examined in each group using diffusion-weighted MRI and/or clinical symptoms. Various measurements were performed on digital subtraction angiography, and the risk factors for medullary infarction were analyzed. RESULTS Medullary infarction occurred in 30 patients, affecting the posterolateral medulla in 27 patients and the anteromedial medulla in 3 patients. Medullary infarction occurred in 3 of 47 patients (6%) in the distal VA stump group, 10 of 19 patients (53%) in the proximal VA stump group, and 17 of 34 patients (50%) in the entire VA stump group. The length of trapping was significantly longer in the infarction group than in the noninfarction group but did not differ among the 3 groups. Total length (length of trapping plus VA stump) was a risk factor for medullary infarction in the proximal VA stumps. CONCLUSIONS The primary risk factor for medullary infarction after EIT is not the length of trapping; rather, it is the anatomical location of the VADAs. The risk of medullary infarction is low in cases with distal VA stumps, but the symptoms are severe. Preservation of the origin of the anterior spinal artery can reduce the risk of medullary infarction. The risk of medullary infarction is high in cases with proximal VA stumps, but the symptoms are mild. A shorter length of trapping, although less likely to lead to complications, cannot prevent medullary infarction because the total length depends on the anatomical location of the PICA and not on the surgical technique. Reconstructive therapy should be indicated for patients with ruptured VADAs at high risk of severe ischemic complications (e.g., patients with hypoplasia of the contralateral VA or cases involving the PICA or anterior spinal artery, which are inappropriate for partial internal trapping) or for patients with unruptured VADAs.

Overlapping stent-assisted coil embolization for a ruptured intracranial vertebral artery dissection

Ruptured intracranial vertebral artery dissection is a cause of non-traumatic subarachnoid hemorrhage. Urgent intervention should be considered to prevent fatal rebleeding. Endovascular parent artery occlusion, which is the initial treatment of choice, is not suitable for patients with a hypoplastic or occlusive contralateral vertebral artery. We report a case of ruptured vertebral artery dissection, which was successfully treated with double overlapping stent-assisted coiling.

Efficacy of high-resolution cone-beam CT in the evaluation of perforators in vertebral artery dissection

Introduction A major complication of internal coil trapping for vertebral artery dissection (VAD) is medullary infarction associated with perforator occlusion. Currently, higher spatial resolution imaging can be obtained with high-resolution cone-beam computed tomography (VASO CT), and the efficacy of perforator visualization adjacent to VAD was examined. Methods Eight patients who underwent internal coil trapping or stent-supported coil embolization underwent VASO CT to evaluate perforators around VAD. Visualization of perforators was compared with conventional digital subtraction angiography (DSA) and three-dimensional rotational angiography (3D-RA). Postoperative MRI was performed in all patients to investigate ischemic complications. The relationship between the perforators and the infarction was analyzed. Results Perforator visualization was much clearer on VASO CT than on 2D DSA or 3D-RA. It was sharp enough to identify each perforating artery. Medullary infarctions were detected in two cases. In these two cases, each ischemic lesion corresponded to the territory of a perforator that was well visualized on VASO CT. The axial view with adjoining tissue structures on VASO CT was useful to detect the territories of perforators. Conclusions VASO CT is an efficient modality for the detection and identification of perforators in the vicinity of VAD. It provides accurate anatomical information about the vertebrobasilar system that is useful for the treatment of unruptured VAD.

Therapeutic Progress in Treating Vertebral Dissecting Aneurysms Involving the Posterior Inferior Cerebellar Artery

Among the variations of vertebral artery dissecting aneurysms (VDAs), VDAs involving the posterior inferior cerebellar artery (PICA), especially ruptured and high-risk unruptured aneurysms, are the most difficult to treat. Because the PICA is an important structure, serious symptoms may occur after its occlusion. Retained PICAs are prone to re-bleeding because VDAs are difficult to completely occlude. There is therefore confusion regarding the appropriate treatment for VDAs involving the PICA. Here, we used the PubMed database to review recent research concerning VDAs that involve the PICA, and we found that treatments for VDAs involving the PICA include (i) endovascular treatment involving the reconstruction of blood vessels and blood flow, (ii) occluding the aneurysm using an internal coil trapping or an assisted bypass, (iii) inducing reversed blood flow by occluding the proximal VDA or forming an assisted bypass, or (iv) the reconstruction of blood flow via a craniotomy. Although the above methods effectively treat VDAs involving the PICA, each method is associated with both a high degree of risk and specific advantages and disadvantages. The core problem when treating VDAs involving the PICA is to retain the PICA while occluding the aneurysm. Therefore, the method is generally selected on a case-by-case basis according to the characteristics of the aneurysm. In this study, we summarize the various current methods that are used to treat VDAs involving the PICA and provide schematic diagrams as our conclusion. Because there is no special field of research concerning VDAs involving the PICA, these cases are hidden within many multiple-cases studies. Therefore, this study does not review all relevant documents and may have some limitations. Thus, we have focused on the mainstream treatments for VDAs that involve the PICA.