Fourth-generation bypass and flow reversal to treat a symptomatic giant dolichoectatic basilar trunk aneurysm.

BACKGROUND: Giant dolichoectatic basilar trunk aneurysms have an unfavorable natural history and are associated with high morbidity, but their neurosurgical treatment is complex and challenging. METHODS: Flow reversal reconstruction with fourth-generation bypass and proximal vertebral artery clip occlusion is performed via orbitozygomatic craniotomy with the Kawase approach under rapid ventricular pacing. CONCLUSION: Fourth-generation bypass is an innovative, technically challenging, and clinically effective tool in the treatment armamentarium for giant dolichoectatic basilar trunk aneurysms.

Anatomical Variations of Vertebrobasilar Artery are Closely Related to the Occurrence of Vertebral Artery Dissection-An MR Angiography Study.

GOAL: Intracranial arterial dissection is a major cause of ischemic stroke and subarachnoid hemorrhage in relatively young patients. We assessed the hypothesis that the tortuosity of the vertebrobasilar artery is associated with the occurrence of vertebral artery (VA) dissection, using MR angiography (MRA). MATERIALS AND METHODS: This study enrolled 43 patients with VA dissection, and 63 age- and sex-matched healthy subjects were used as the controls. MRA was employed to evaluate the presence of dominant VA and the lateral shift of vertebrobasilar junction in both groups. The VA diameters were considered different when the difference was greater than .3 mm. These anatomical variations were divided into 3 types: Type 1 (vertebrobasilar junction within 2 mm from the midline), Type 2 (>2 mm-lateral shift of vertebrobasilar junction to the ipsilateral side of the dominant VA), and Type 3 (>2 mm-lateral shift of vertebrobasilar junction to the contralateral side of the dominant VA). FINDINGS: The presence of dominant VA and the lateral shift of vertebrobasilar junction were more prevalent in patients with VA dissection than in the controls (OR: 3.46, P = .013, and OR: 4.51, P = .001, respectively). The lateral shift of vertebrobasilar junction was classified into Type 1 (n = 6), Type 2 (n = 13), and Type 3 (n = 17) among patients with VA dissection, while into Type 1 (n = 20), Type 2 (n = 8), and Type 3 (n = 7) among the controls. Type 3 predominance was observed in patients with VA dissection (P = .02). CONCLUSIONS: Anatomical variations of the vertebrobasilar artery may play an important role in the occurrence of VA dissection.

Evaluation of flow changes after telescopic stenting of a giant fusiform aneurysm of the vertebrobasilar junction.

BACKGROUND: The use of flow-diverters for non-saccular cerebral posterior circulation aneurysms requires complex deployment techniques and is associated with high mortality and morbidity. Therefore, further studies are required to clarify the effect of stenting on post-treatment hemodynamics in such aneurysms. In this study, we evaluated flow alterations in a treated giant fusiform aneurysm of the vertebrobasilar junction and correlated them with the clinical outcome. METHODS: A patient-specific aneurysm model was acquired by rotational angiography, and three SILK flow-diverters (4.5 × 40, 5 × 40 and 5.5 × 40 mm) were virtually deployed in series along the basilar and right vertebral arteries. Image-based blood flow simulations before and after the treatment were performed under realistic pulsatile flow conditions. The flow reduction, velocity and wall shear stress (WSS) distribution, streamlines and WSS-derived parameters were evaluated before and after the treatment. RESULTS: The computed velocity streamlines showed substantial alterations of the flow pattern in the aneurysm and successful redirection of blood flow along the series of flow-diverters with no flow through the overlapping stents. The obtained flow reduction of 86% was sufficient to create thrombogenic flow conditions. Moreover, a 6.2-fold increase in relative residence time and a decrease by 87% of time-averaged WSS contributed to a successful treatment outcome observed during the follow-up. CONCLUSIONS: We found a correlation between the numerically predicted flow alterations and the available treatment outcome. This shows the potential of image-based simulations to be used in clinical practice for treatment planning and estimation of possible risk factors associated with a complex stent deployment in fusiform aneurysms of the posterior circulation.

How I do it: surgical clipping of vertebrobasilar junction aneurysms through a far-lateral transcondylar approach.

BACKGROUND: Vertebrobasilar junction aneurysms occur rarely, but have a higher rupture rate than supratentoral aneurysms, and higher morbidity and mortality. Their location ventral to the neuroaxis makes them a challenging surgical lesion. METHODS: In this paper, we share our experience with the surgical technique for the management of these complex aneurysms. CONCLUSION: An in-depth understanding of the anatomy of these aneurysms, careful preoperative planning, and a meticulous surgical technique, including knowledge of every detail of the procedure-positioning, an advanced skull base technique, and careful aneurysm dissection and clipping-is essential for a successful outcome of the surgery.

A Case of Ruptured Vertebrobasilar Junction Aneurysm Associated with Subclavian Steal Phenomenon.

A 77-year-old woman with arteriovenous shunt for hemodialysis in the left forearm suffered from subarachnoid hemorrhage due to the rupture of a saccular aneurysm located on the left lateral wall of vertebrobasilar junction. Her left subclavian artery was severely stenosed and subclavian steal phenomenon was demonstrated on the digital subtraction angiography. Embolization of the parent artery including the aneurysm using detachable coils resulted in the successful obliteration of the aneurysm through the revascularized left subclavian artery. This is the first case in which the vertebrobasilar junction aneurysm would be caused by the hemodynamic stress due to the subclavian steal phenomenon combined with the shunt for hemodialysis in the left forearm.

Vertebrobasilar junction giant aneurysm: Lessons learned from a neurosurgical audit and anatomical investigation.

The treatment of vascular lesions of the vertebrobasilar junction (VBJ) remains a challenging task in the neurosurgical practice and the gold standard therapy is still under debate. In this article, the authors report a detailed postmortem study of a VBJ giant aneurysm (GA) previously endovascularly treated. Although the decision-making process for the vast majority of neurosurgical treatment can nowadays be accurately carried out during the preoperative planning (i.e., with the aid of neuroimaging fusion protocols, neuronavigation platforms, etc.) meant to maximize the anatomical understanding of the lesions and minimize possible intraprocedural challenges, this postmortem study represents the ultimate essence of neurosurgical audit as the laboratory investigations allowed to reevaluate the clinical history of VBJ GA, and reassess the multiple strategies available for its treatment with a straightforward anatomical perspective. Specifically, the lessons learned through this clinical and laboratory work uphold a great educational value regarding the complex management of those lesions, including the possible role of combined skull base surgical approaches.

A vertebrobasilar junction aneurysm successfully treated with a combination of surgical clipping and flow diverter placement based on the results of computational fluid dynamics analysis: illustrative case.

BACKGROUND: The treatment of vertebrobasilar junction (VBJ) aneurysms is challenging. Although flow diverters (FDs) are a possible treatment option, geometrical conditions hinder intervention. VBJ aneurysms possess dual inflow vessels from the bilateral vertebral arteries (VAs), one of which is ideally occluded prior to FD treatment. However, it remains unclear which VA should be occluded. OBSERVATIONS: A 75-year-old male with a growing VBJ complex aneurysm exhibiting invagination toward the brainstem and causing perifocal edema required intervention. Preoperative computational fluid dynamics (CFD) analysis demonstrated that left VA occlusion would result in more stagnant flow and less impingement of flow than right VA occlusion. According to the simulated strategy, surgical clipping of the left VA just proximal to the aneurysm was performed, followed by FD placement from the basilar artery trunk to the right VA. The patient demonstrated tolerance of the VA occlusion, and follow-up computed tomography angiography at 18 months after FD treatment confirmed the disappearance of the aneurysm. LESSONS: Preoperative flow dynamics simulations using CFD analysis can reveal an optimal treatment strategy involving a hybrid surgery that combines FD placement and direct surgical occlusion for a VBJ complex aneurysm.

A Case With Twists and Turns: A Report of Vertebrobasilar Dolichoectasia.

Vertebrobasilar dolichoectasia (VBD) is a rare anatomical abnormality of the vertebral artery system, defined as irregular expansion, elongation, and tortuosity of vertebral arteries. Anomalies of the vertebrobasilar artery can have a wide variety of clinical presentations, ranging from simple headaches to debilitating strokes. We present the case of an atypical presentation of VBD which mimicked trigeminal neuralgia by compressing the trigeminal nerve. There are currently no guidelines concerning the management of VBD, nor is there evidence of a definitive cure. This case invoked discussions among the medical team as to whether management should be medically or surgically focused, as well as long-term outcomes for patients with VBD. The superiority of medical versus surgical treatment of this issue is still a debated topic. This patient trialed medical management with dexamethasone and carbamazepine with no improvement in symptoms. He then underwent surgical gamma knife treatment but even this invasive measure was unsuccessful at relieving his symptoms. We hope that by presenting this case, we can display how the therapies available for VBD are limited and often unsuccessful in relieving the disease burden in patients with VBD.

Endovascular treatment outcomes of vertebrobasilar junction aneurysms: Systematic review and meta-analysis.

BACKGROUND: Vertebrobasilar junction (VBJ) aneurysms represent a relatively rare and often anatomically complex subgroup of saccular aneurysms. This systematic review and meta-analysis aimed to assess the safety and efficacy of endovascular treatment (EVT) of VBJ aneurysms. METHODS: PubMed, Web of Science, Ovid Medline, Ovid Embase, and Scopus were searched from inception to 20 December 2022. We included primary studies assessing the long-term clinical and angiographic outcomes for VBJ aneurysms treated with endovascular techniques. We excluded surgically managed studies. All data were analyzed using R software version 4.2.1. We calculated pooled prevalence rates and their corresponding 95% confidence intervals (CI). RESULTS: In this meta-analysis, a total of 76 VBJ aneurysms from seven studies were included for quantitative analysis. The results showed that the rate of adequate occlusion (complete + near complete occlusion) was 94.1% (95% CI = 76.71-98.71), and the rate of complete occlusion was 77.7% (95% CI = 63.07-87.65). A modified Rankin Scale (mRS) score of 0-2 was achieved in 93.9% of patients (95% CI = 67.65-99.14). The mortality rate was found to be 5.9% (95% CI = 0.97-28.55), and the retreatment rate was 4.6% (95% CI = 1.50-13.36). The overall ischemic complication rate was 4.7% (95% CI = 0.73-25.4), while the overall hemorrhagic complication rate was 4.6% (95% CI = 1.5-13.36). CONCLUSIONS: The treatment of VBJ aneurysms with EVT is effective in achieving curative treatment and is associated with good clinical outcomes and low mortality rates. These findings provide important insights into the clinical and angiographic outcomes and the complication rates of EVT for VBJ aneurysms.

Reconstructive Endovascular Treatment of Basilar Trunk and Vertebrobasilar Junction Aneurysms: A Review of 77 Consecutive Cases.

Background: Basilar trunk and vertebrobasilar junction (BTVBJ) aneurysms have a poor prognosis and are challenging to treat. Objective: This study aimed to evaluate the efficacy of reconstructive endovascular treatment for BTVBJ aneurysms and explore a treatment selection paradigm. Methods: Clinical and angiographic data from 77 patients with 80 BTVBJ aneurysms who underwent endovascular treatment with flow diverters (FDs) or conventional stent-assisted coiling between January 2016 and December 2020 were retrospectively analyzed. Aneurysm characteristics and treatment outcomes were compared between treatment groups. Results: Among the 77 study patients, 34 (44.2%) were treated with FDs and 43 (55.8%) with conventional stent-assisted coiling. Overall, 72.7% of patients achieved favorable clinical outcome at follow-up. The rate of procedure-related complications was 23.4%. The aneurysm occlusion rate at last follow-up did not differ between the FD and conventional stent groups (79.2% vs. 77.1%, p = 0.854). Although the occlusion rate immediately after the procedure was lower in the FD group (29.4%), incidence of progressive occlusion was significantly higher (62.5 vs. 5.7%; p < 0.001). The proportion of patients with large and giant aneurysms (≥10 mm) was significantly higher in the FD group (70.6 vs. 34.8%; p = 0.002). In patients with large or giant aneurysms, favorable clinical outcome at last follow-up was achieved in 75% of patients in the FD group but only 43.8% of patients in the conventional stent group (p = 0.046). Moreover, the complication rate was lower in the FD group, but the difference was not significant (20.8 vs. 37.5%; p = 0.247). The same analyses were performed for patients with small aneurysms (<10 mm) but no significant differences between the two groups were observed. Conclusion: Endovascular treatment of small BTVBJ aneurysms using either FDs or conventional stents was feasible and effective. In patients with large or giant aneurysms, treatment using FDs achieved higher rates of occlusion and favorable clinical outcome at last follow-up than conventional stent-assisted coiling.

Endovascular assisted vertebrobasilar junction aneurysm clipping in a hybrid operation room. Case report.

Introduction: We present a case of a 60-year-old female that underwent surgery for clipping a right vertebrobasilar junction aneurysm (VBJA) in a hybrid operation room. Research question: Does the retrograde suction technique with a proximal balloon is safe and effective as an adjuvant technique in surgery of VBJA? Material and methods: After an extended retrosigmoid approach was performed, a 6F Neuron catheter with an intermediate multipurpose catheter were navigated to the right vertebral artery (VA) through a 6-French sheath, which caused a severe catheter-induced vasospasm in the right VA. The aneurysm was then deflated and clipped. After the withdrawal of the catheter the vasospasm was resolved. Results: The patient had a good recovery, with VI cranial nerve palsy and mild dysphagia due to mild right vocal cord palsy, both improving at 1-month follow-up and fully recovered at 6-month follow-up. Discussion and conclusion: The combination of endovascular procedures and microsurgery at the same hybrid operation room in that case resulted in a safe and effective technique. It is an interesting tool that could help neurosurgeons deal with certain selected cases of VBJA. Intraoperative angiography offers the possibility to reposition a misplaced clip in the same surgery. Good collaboration between interventional neuroradiologists and vascular neurosurgeons helps in achieving good results in such difficult cases.

Giant aneurysm of the bilateral vertebrobasilar junction treated by pipeline and coils: A case report and literature review.

Giant aneurysm of the posterior circulation is associated with a higher risk of rupture compared with that of the anterior circulation. Furthermore, surgical clipping and interventional embolization for giant aneurysm of the posterior circulation are more difficult and complex to perform. The present study reported on the case of a 26-year-old female who exhibited a giant spherical aneurysm of the vertebrobasilar junction (VBJ) with a maximum diameter of ~35 mm that caused cervical discomfort. In addition, the patient experienced symptoms including left-sided walking and hoarseness caused by the compression of the brainstem and the posterior cranial nerves. The risks associated with performing surgery in this area are high and the prognosis is mainly poor. The patient of the present study was treated using the Pipeline Flex device with coil embolization. As a giant aneurysm of the VBJ simultaneously affects the bilateral vertebral arteries (VAs) and basilar artery, it is a unique condition and the treatment strategy must be personalized. Based on an analysis of the hemodynamic influence on the aneurysm in the present case, the Pipeline was placed through the left VA, the coils were packed through the right VA, and finally, the right VA was proximally occluded. At 7 months after embolization, the patient's modified Rankin scale score was 1 point. Upon analysis of the hemodynamic influence on the aneurysm of the VBJ, the VA with the larger shear force on the wall of the aneurysm was selected for occlusion to simplify the treatment of the aneurysm and to maximize the probability to achieve recovery.

Vertebrobasilar Junction Angle Over 90°: A Potential Imaging Marker Associated With Vertebrobasilar Atherosclerosis.

Objective: Whether the cerebral vascular variations play an important role in the progression of intracranial atherosclerosis is yet largely unclear. We aimed to investigate the relationship between the magnitude of the vertebrobasilar junction (VBJ) angle and the imaging features of vertebrobasilar artery atherosclerosis. Methods: Adult patients with acute ischemic stroke or transient ischemic attack undergoing a 3.0-tesla vessel wall magnetic resonance imaging (VW-MRI) scanning were consecutively included. Imaging features of vertebrobasilar artery atherosclerosis were assessed on the reconstructed short axis of VW-MRI at the most stenotic site. The VBJ angle degree was measured on magnetic resonance angiography and classified into the angle ≥90° or <90°. Results: Among 68 patients (mean age = 63.5 ± 9.4 years old; 63.2% were male) with vertebrobasilar atherosclerosis, 33 had a VBJ angle ≥90° and 35 had a VBJ angle <90°. Compared to the vertebrobasilar plaques with VBJ angle <90°, those with VBJ angle ≥90° had a heavier plaque burden (84.35 vs. 70.58%, p < 0.001) and higher prevalence of intraplaque hemorrhage (17.1 vs. 3.3%, p = 0.01). In the regression analyses, the VBJ angle ≥90° was also robustly associated with plaque burden (odds ratio, 1.11; 95% confidential interval, 1.043-1.18; p = 0.001) and intraplaque hemorrhage (odds ratio, 5.776; 95% confidential interval, 1.095-30.46; p = 0.039) of vertebrobasilar atherosclerosis. Conclusion: The VBJ angle over 90° might aggravate the vessel wall condition of the atherosclerotic vertebrobasilar arteries, which might serve as a potential risk factor for vertebrobasilar atherosclerosis.

The Benefits of Progressive Occipital Condylectomy in Enhancing the Far Lateral Approach to the Foramen Magnum.

BACKGROUND: The portion of the occipital condyle that is safe to remove remains controversial in the transcondylar approach. We aimed to correlate the gain in exposure with incremental removal of the occipital condyle to determine if there is a point where further drilling yields diminishing gains. METHODS: Virtual reality rendering of the skull was generated from 25 subjects with no posterior fossa pathology. A suboccipital far lateral craniotomy was done in virtual reality space, stopping at the posterior edge of the occipital condyle. Angular measurements of surgical corridor were taken at this point and after removal of 25% and 50% of the condyle. Two surgical targets were used: at the anterior midline of the foramen magnum and the vertebrobasilar junction. RESULTS: Progressive removal of the occipital condyle increased exposure to both targets in a linear fashion. For the midline of the foramen magnum, the working angle increased from 12° to 18° for quarter condylectomy and then to 25° for half condylectomy. The corridor to the vertebrobasilar junction was much tighter, and the angle increased from 5.5° to 9° for quarter condylectomy and then to 12° for half condylectomy. The gain in exposure for the low target was greater than for the high target (P < 0.001). CONCLUSIONS: Progressive removal of the occipital condyle yielded a linear increase in exposure without an ideal point beyond which the drilling was futile. However, the impact of condylectomy was greater for our low target compared with our high target.

Giant Fusiform and Dolichoectatic Aneurysms of the Basilar Trunk and Vertebrobasilar Junction-Clinicopathological and Surgical Outcome.

BACKGROUND: Giant fusiform and dolichoectatic aneurysms of the basilar trunk and vertebrobasilar junction (BTVBJ-GFDA) are extremely difficult to treat. OBJECTIVE: To evaluate factors influencing survival and outcome of BTVBJ-GFDA by performing a retrospective multicenter cohort study. METHODS: A total of 32 patients with BTVBJ-GFDA were included in this study. Clinicopathological characteristics, treatment measures, and outcomes were collected from medical records and imaging studies. Autopsy and histological findings of the aneurysm and adjacent brain tissue were also obtained in 9 cases. RESULTS: A total of 11 patients did not undergo surgery, of whom 10 died; 3 from progressive brainstem compression, 4 from subarachnoid hemorrhage, 2 from brainstem infarction, and 1 from associated atherosclerotic disease. The remaining 21 patients underwent a surgical treatment, consisting of immediately proximal parent artery occlusion, remotely proximal parent artery occlusion, clip reconstruction, and distal bypass and achieved significantly longer overall survival compared with those who received conservative therapy (adjusted hazard ratio 1.508, 95% CI 1.058-2.148, P = .02). Histological examination of the aneurysms demonstrated staged clots, open lumen, and intrathrombotic channels with endothelial lining. The patients younger than 45 yr of age showed statistically longer survival than those equal and older than 45 yr (P = .03). CONCLUSION: Surgical intervention achieved greater survival than conservative management in BTVBJ-GFDA. Narrow ideal treatment window of the blood flow within the aneurysm to maintain sufficient but not excess supply should be targeted based on the hemodynamics of both the posterior communicating arteries and perforating vessel collaterals.

Subclavian Steal Flow-Related Aneurysm Formation.

Subclavian steal phenomenon can cause retrograde flow through the ipsilateral vertebral artery as a result of atherosclerosis of the subclavian artery. Clinically this can present as intermittent vertebrobasilar ischemia or claudication of the affected extremity, but rarely it poses a serious risk of neurologic morbidity or mortality. Aneurysm formation at the vertebrobasilar junction is rare but may occur as a sequela of increased flow through 1 vertebral artery, as occurs in subclavian steal syndrome. Here, we present a rare case of subarachnoid hemorrhage from a vertebrobasilar junction aneurysm related to subclavian steal syndrome.

Flow Diverter Therapy of a Giant Fusiform Vertebrobasilar Junction Aneurysm in a Child: Case Report.

The management of giant vertebrobasilar junction (VBJ) aneurysms is extremely challenging. Flow diverter (FD) therapy has become an important alternative to treat difficult intracranial aneurysms for both open surgery and conventional endovascular therapy. Herein, we report a rare case of a giant fusiform VBJ aneurysm in a child that is successfully treated with FD therapy.

Treatment of fenestrated vertebrobasilar junction-related aneurysms with endovascular techniques.

Fenestrated vertebrobasilar junction-related aneurysms (fVBJ-AN) are uncommon and endovascular management strategies have become the first options for the treatment of these lesions. This clinical study aimed to report our experience in the endovascular management of these lesions and to review the literature. We retrospectively reviewed 10 consecutive patients harboring 12 fVBJ-AN between January 2007 and December 2014. The demographic, angiographic and clinical data were reviewed. Additionally, a literature review was performed. Endovascular management strategies were successfully applied in all 10 patients. Post-procedural angiograms indicated total occlusion in eight (66.7%) aneurysms, a residual neck in one (8.3%) aneurysm, and three residual aneurysms (25%). No procedure-related complications were observed. Follow-up angiograms were obtained in eight patients and revealed nine occluded aneurysms and one improved aneurysm; two patients were lost to angiographic follow-up. Clinical follow-ups were obtained in all patients (until July 2015), and the modified Rankin Scale scores at 69.5months (range 17-101months) of follow-up were 0 in eight patients and 1 in two patients. Endovascular management strategies provided a high occlusion rate and an acceptable complication rate and are thus efficacious in the treatment of fVBJ-AN. Further studies are necessary to validate the utility of these treatments due to the low incidence of fVBJ-AN.

Brainstem arteriovenous malformations: anatomical subtypes, assessment of "occlusion in situ" technique, and microsurgical results.

OBJECT: The surgical management of brainstem arteriovenous malformations (AVMs) might benefit from the definition of anatomical subtypes and refinements of resection techniques. Many brainstem AVMs sit extrinsically on pia mater rather than intrinsically in the parenchyma, allowing treatment by occluding feeding arteries circumferentially, interrupting draining veins after arteriovenous shunting is eliminated, and leaving the obliterated nidus behind. The authors report here the largest series of brainstem AVMs to define 6 subtypes, assess this "occlusion in situ" technique, and analyze the microsurgical results. METHODS: Brainstem AVMs were categorized as 1 of 6 types: anterior midbrain, posterior midbrain, anterior pontine, lateral pontine, anterior medullary, and lateral medullary AVMs. Data from a prospectively maintained AVM registry were reviewed to evaluate multidisciplinary treatment results. RESULTS: During a 15-year period, the authors treated 29 patients with brainstem AVMs located in the midbrain (1 anterior and 6 posterior), pons (6 anterior and 7 lateral), and medulla (1 anterior and 8 lateral). The nidus was pial in 26 cases and parenchymal in 3 cases. Twenty-three patients (79%) presented with hemorrhage. Brainstem AVMs were either resected (18 patients, 62%) or occluded in situ (11 patients, 38%). All lateral pontine AVMs were resected, and the occlusion in situ rate was highest with anterior pontine AVMs (83%). Angiography confirmed complete obliteration in 26 patients (89.6%). The surgical mortality rate was 6.9%, and the rate of permanent neurological deterioration was 13.8%. At follow-up (mean 1.3 years), good outcomes (modified Rankin Scale [mRS] score ≤ 2) were observed in 18 patients (66.7%) and poor outcomes (mRS score of 3-5) were observed in 9 patients (33.3%). The mRS scores in 21 patients (77.8%) were unchanged or improved. The best outcomes were observed with lateral pontine (100%) and lateral medullary (75%) AVMs, and the rate of worsening/death was greatest with posterior midbrain and anterior pontine AVMs (50% each). CONCLUSIONS: Brainstem AVMs can be differentiated by their location in the brainstem (midbrain, pons, or medulla) and the surface on which they are based (anterior, posterior, or lateral). Anatomical subtypes can help the neurosurgeon determine how to advise patients, with lateral subtypes being a favorable surgical indication along with extrinsic pial location and hemorrhagic presentation. Most AVMs are dissected with the intention to resect them, and occlusion in situ is reserved for those AVMs that do not separate cleanly from the brainstem, that penetrate into the parenchyma, or are more anterior in location, where it is difficult to visualize and preserve perforating arteries (anterior pontine and lateral medullary AVMs). Although surgical morbidity is considerable, surgery results in a better obliteration rate than nonoperative management and is indicated in highly selected patients with high rerupture risks.

Vertebro-basilar junction aneurysms: a single centre experience and meta-analysis of endovascular treatments.

Vascular lesions of the vertebrobasilar junction (VBJ) are challenging in neurosurgical practice, and their gold-standard therapy is still under debate. We describe the operative strategies currently in use for the management of these complex vascular lesions and discuss their rationale in a literature meta-analysis and single centre blinded retrospective study. The single centre study included a review of initial presentation, angiographic features and clinical outcome (with modified Rankin Scale [mRS] scores) over a long-term follow-up. In our series, small aneurysms were effectively treated by endosaccular coil embolization, whereas a strategy including flow-diverter devices combined with endosaccular coil embolization was the option of choice in large and giant aneurysms, leading to satisfactory outcomes in most cases. Our Medline review showed that endovascular treatment was chosen in most VBJ cases, whereas the microsurgical option was assigned to only a few cases. Among the endovascular treatments, the most common techniques used for the treatment of VBJ aneurysms were: coiling, stent-assisted coiling and flow diversion. Our study highlights that aneurysm morphology, location and patient-specific angio-architecture are key factors to be considered in the management of VBJ aneurysms. Most case series, including our own, show that parent artery reconstruction using a flow-diverter device is a feasible and successful technique in some cases of giant and complex aneurysms (especially those involving the lower third of the basilar artery) while a "sit back, wait and see" approach may represent the safest and most reasonable option.