Basilar Apex Aneurysm: Case Series, Systematic Review, and Meta-analysis

Open Microsurgical Versus Endovascular Management of Unruptured and Ruptured Brain Aneurysms

Open microsurgical and endovascular techniques are the 2 primary strategies for treating intracranial aneurysms. Microsurgical clipping and adjuvant technical maneuvers are well-established techniques with a track record for high occlusion rates and durable repairs. Endovascular, endosaccular, and extrasaccular therapies are associated with lower peri-procedural morbidity but with generally higher rates of retreatment. We discuss key clinical and anatomic considerations in treatment decision-making and compare the risks and benefits of microsurgical vs endovascular treatment within each context.

Endovascular Treatment of Basilar Apex Aneurysms: An Updated Systematic Review and Meta-Analysis in the Era of Flow Diversion

BACKGROUND

Endovascular options for the treatment of basilar apex aneurysms (BAAs) are heterogeneous, and evidence is limited to retrospective cohorts and case series. We seek to evaluate the efficacy and complications associated with various endovascular treatment methods of BAAs.

METHODS

Systematic review of PubMed, Embase, and Web of Science adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Retrospective and prospective studies evaluating endovascular treatment of BAAs between January 2010 and July 2024 were included. Relevant information including occlusion rates, aneurysm recurrence, retreatment rates, and complications were subjected to meta-analysis.

RESULTS

Fifteen studies with 1049 BAAs were included. The median aneurysm diameter was 8.5 mm (range, 4.6-19.75), with a median follow-up of 33.7 months (range, 6.0-117.6). Residual aneurysm filling occurred in 24% after primary coiling (95% CI = 0.16-0.32), 25% after single stent-assisted coiling (s-SAC; 95% CI = 0.04-0.46), 25% after Y-stents (95% CI = 0.12-0.37), and 23% after flow diverter stent (FDS; 95% CI = 0.11-0.35). Recurrence rates were high for primary coiling (27%, 95% CI = 0.18-0.36) and s-SAC (19%, 95% CI = 0.13-0.26), but significantly lower for Y-stents (9%, 95% CI = 0.03-0.15) and FDS (4%, 95% CI = -0.04-0.11). Retreatment rates were 19% for primary coiling (95% CI = 0.12-0.26), 17% for s-SAC (95% CI = 0.07-0.27), 5% for Y-stents (95% CI = -0.03-0.12), and 13% for FDS (95% CI = -0.01-0.27). Meta-regression indicated larger aneurysms had higher complication rates (P = 0.02). Thromboembolic events were most frequent with FDS and Y-stents(12%).

CONCLUSIONS

Occlusion rates were similar across treatments, but recurrence rates were significantly lower after Y-stents and FDS compared to primary coiling, although they carried a higher number of thromboembolic complications.

Current research status and future of endovascular treatment for basilar artery aneurysms

Aneurysms occurring along the basilar artery (BA) account for <1% of all intracranial aneurysms. Endovascular treatment (EVT) in particular is recommended for large unruptured BA aneurysms and ruptured BA aneurysms. Given that EVT techniques vary, a detailed review of EVT for BA aneurysms is necessary. In this review, the following issues were discussed: the anatomy and anomalies of the BA, the classification of BA aneurysms, the natural history of BA aneurysms, the status of open surgery, the use of EVT for various types of BA aneurysms and the deployment of new devices. According to the findings of this review and based on our experience in treating BA aneurysms, traditional coiling EVT is still the optimal therapy for most BA aneurysms. However, in some BA aneurysms, flow diverter (FD) deployment can be used. In addition, there are also some new devices, such as intrasaccular flow disruptors and stent-like devices that can be used to treat BA aneurysms. In general, EVT can yield good clinical and angiographic outcomes for patients with BA aneurysms. In addition, recent new devices and techniques, such as new-generation FDs generated via surface modification and virtual reality simulation techniques, show promise for EVT for BA aneurysms. These devices and techniques may further improve EVT outcomes for BA aneurysms.

Open surgical treatment of basilar artery aneurysms in the interventional therapy era

PURPOSE

The purpose of this study was to describe the effectiveness and evaluation of open surgical treatment of basilar artery aneurysms in the context of interventional therapy era, including surgical clipping and blood reconstruction, by retrospectively analyzing the clinical data of basilar artery aneurysms in our center.

METHODS

Patients with basilar artery aneurysms who were treated at our center were retrospectively included according to the inclusion and exclusion criteria. The basic clinical data, surgical approach, clinical follow-up and prognosis of the enrolled patients were analyzed in detail. In this study, the mRS score was applied to assess the neurological prognosis of the patients, and the relevant data were statistically analyzed using SPSS.

RESULTS

A total of 104 eligible patients treated at our center from January 2010 to August 2023 were included in this study, of which 67 were treated by open surgery and 37 by bypass. For the 67 patients with open surgical clipping, the mean age was 60.0 (52.0, 65.0) years. The maximum diameter of the aneurysms ranged from 2.0 mm to 54.0 mm, with a mean of 13.9 (10.0, 19.0) mm. The mean follow-up time was 38 (20, 58) months. At the last follow-up, 61 (91.0%) completely obliterated aneurysms and 6 (9.0%) incompletely obliterated aneurysms were found. The prognosis was good in 59 (88.1%) patients and poor in 8 (11.9%). After surgical clipping, the difference between complete and incomplete postoperative aneurysm elimination was statistically significant between the favorable and poor prognosis groups (P < 0.001). For the 37 bypass group patients, the mean age was 52.0 (45.5, 59.0) years. The maximum diameter of the aneurysm ranged from 10.5 mm to 55.0 mm, with a mean of 28.55 ± 12.08 mm. Bypass combined with proximal occlusion was performed in 18 (48.6%) patients, and bypass only was performed in 19 (51.4%) patients. Clinical follow-up was 19.0 (10.5, 43.0) months. There were 19 (51.4%) patients with complete elimination of the aneurysm, 13 (35.1%) with incomplete elimination of the aneurysm, and 5 (13.5%) with aneurysm stabilization. The prognosis was good in 32 (86.5%) patients and poor in 5 (13.5%) patients.

CONCLUSION

Treatment of basilar artery aneurysms is challenging. In the context of the rapidly evolving interventional therapy era, open surgery including surgical clipping and bypass is an ideal option for complex basilar artery aneurysms not amenable to intervention.

Impact of size ratio on thromboembolic events based on diffusion-weighted imaging after coil embolization for unruptured basilar apex aneurysm

PURPOSE

Coil embolization is one of the main endovascular treatment for basilar apex aneurysms (BAAs), and thromboembolic events are important complications of coil embolization. Even in small aneurysms, there is a risk of rupture, and aggressive treatment should be considered for unruptured BAAs. Using diffusion-weighted imaging (DWI), the study aimed to investigate thromboembolic events after coil embolization for unruptured BAAs by focusing on the absolute aneurysm size and relative aneurysm size (size ratio [SR]).

METHODS

To evaluate the predictors of thromboembolic events, patients were divided into those with and without hyperintensity on DWI after coil embolization. Patient and radiographic characteristics were compared between the two groups. SR was defined as the maximum aneurysm diameter divided by the average parent artery diameter.

RESULTS

Fifty-six unruptured BAAs in 56 patients were investigated. The mean aneurysm size and SR were 7.61 ± 2.18 mm and 2.74 ± 1.45, respectively. Postprocedural hyperintensity on DWI was detected in 17 patients (30.4%). SR was significantly larger in the group with hyperintensity on DWI (3.75 ± 1.97 vs. 2.3 ± 0.82, P < 0.01) in the univariate analysis. Multivariate analysis revealed that SR> 3.0 was a significant predictor of thromboembolic events after coil embolization for unruptured BAAs (odds ratio: 12.15; 95% confidence interval: 2.95-49.98; P < 0.01).

CONCLUSIONS

This study showed that SR is a predictor of thromboembolic events after coil embolization for unruptured BAAs. Therefore, if even in small BAAs, if the BAAs dome height is large compared to the diameter of the posterior cerebral artery (e.g., there is a large SR), preoperative evaluation of the use of antiplatelet therapy is important, particularly to prevent thromboembolic events.

Risk factors for recanalization of basilar tip aneurysm after endovascular treatment: a retrospective cohort study

OBJECTIVES

Endovascular treatment (EVT) of basilar tip aneurysms (BTAs) is arduous because of the lesions' angioarchitecture and the relatively high recanalization rate after EVT. In this study, we aimed to report the clinical characteristics of BTAs and evaluate the incidence of and risk factors for recanalization.

METHODS

One hundred twenty-five patients with BTAs (11 ruptured, 114 unruptured) treated with EVT between 2009 and 2019 at one institution were retrospectively reviewed. Among them, 113 patients were included in statistical analyses. The anatomical parameters of the aneurysms and clinical data were analyzed. Univariate (chi-square test and t-test) and multivariate (multiple logistic regression) analyses were performed to identify risk factors for recanalization.

RESULTS

        Recanalization of the BTA occurred in 15 patients (13.3%). One patient (0.9%) was retreated endovascularly. The mean follow-up duration was 49.8 months. Neck size, posterior cerebral artery (PCA) angle, maximum diameter, and the rupture rate differed significantly between the recanalization and non-recanalization groups (P=.007, P<.001, P=.006, and P=.048, respectively). The maximum diameter (odds ratio, 1.483 per mm; 95% confidence interval, 1.145-1.919; P=.003) and PCA angle (odds ratio, 1.020 per degree; 95% confidence interval, 1.001-1.039; P=.036) were independently associated with recanalization.

CONCLUSIONS

Of all investigated BTAs, 96.8% were wide-neck aneurysms. The recanalization rate of BTAs after EVT was 13.3%. The PCA angle and maximal aneurysmal diameter were independently associated with recanalization; no associations were observed regarding vertebral artery dominance or modality of treatment. As such, BTA patients with wide PCA angles should be carefully monitored over time.

[pConus device for endovascular treatment of basilar bifurcation aneurysms]

Aneurysm occlusion with microcoils is an effective and safe procedure. However, bifurcation aneurysms usually have a wide neck, and their occlusion is still a difficult objective.

OBJECTIVE

To evaluate the efficacy and safety of bifurcation stents in the treatment of basilar bifurcation aneurysms.

MATERIAL AND METHODS

A retrospective analysis included 34 patients with basilar bifurcation aneurysms between 2016 and 2022. The pConus bifurcation stent was used as a stent-assistance for endovascular occlusion of aneurysms with microcoils. We analyzed technical features of stent implantation and clinical results of endovascular treatment. Mean aneurysm dimension was 8.4 mm, neck size - 4.6 mm. Preoperative MSR score 0-2 was observed in 94.7% of patients, 3-5 scores - in 5.3% of patients.

RESULTS

There were no significant changes in functional status early after surgery (MSR grading system). Total aneurysm occlusion was achieved in 67.6% of patients, subtotal - 17.6% of cases, partial - 14.8%. There were no technical or early postoperative clinical complications. Six months after surgery, total occlusion was observed in 77.8% of patients, subtotal occlusion - 14.8%, partial occlusion - 4%. MSR score 0-2 was observed between 3 and 12 months after surgery. One patient died from other cause rather aneurysm. Redo intervention due to aneurysm recanalization was performed in 1 patient.

CONCLUSION

The pConus bifurcation stent is effective and safe in endovascular treatment of basilar bifurcation aneurysms of the most complex configuration. There was a minimal risk of aneurysm recanalization in long-term postoperative period.

Transcavernous Approach in Vascular Neurosurgery

The cavernous sinus is no more considered no man's land. It is a very well organized anatomic entity that can safely be navigated. It is both a route and a destination. Unlocking the cavernous sinus provides a highway that can be used to reach different vascular and tumor locations that were deemed very risky to handle.

The Dolenc technique was used to clip 14 cases of ruptured basilar apex aneurysms and posterior cerebral artery aneurysms

Objective

To investigate the surgical techniques and their clinical effects for ruptured basilar artery apex and posterior cerebral aneurysms via the Dolenc approach.

Methods

We retrospectively analyzed the clinical data of 14 patients with ruptured basilar artery apex and posterior cerebral aneurysms who underwent surgical clipping by the Dolenc approach from July 2017 to June 2020 in Beijing Tiantan Hospital affiliated with Capital Medical University and Lianyungang Hospital affiliated with Xuzhou Medical University. The modified Rankin scale (mRs) scores were used to evaluate the prognosis of patients.

Results

All 14 cases of aneurysms were successfully clipped. Overall, 1, 2, and 1 cases of postoperative new-onset visual loss, oculomotor nerve palsy, and contralateral hemiplegia, respectively, were reported. Digital subtraction angiography (DSA) or computed tomography angiography (CTA) examination of the aneurysm within 2 weeks after surgery revealed that the aneurysm was completely clipped without residue. The observations during the follow-up within 12–18 months after surgery were as follows: 1 case of vision loss returned to normal, 2 cases of oculomotor nerve palsy, 1 case of return to normal, 1 case of improved, 1 case of contralateral hemiplegia improved after rehabilitation treatment, and 1 case of hydrocephalus ventriculoperitoneal shunt surgery was performed. Overall, 11, 2, and 1 case had mRs scores of 0, 1, and 2, respectively. No death was reported.

Conclusion

For the small number of basilar apical and posterior cerebral aneurysms treated non-invasively, the Dolenc approach may offer advantages over other modalities.

Comparing treatment outcomes of various intracranial bifurcation aneurysms locations using the Woven EndoBridge (WEB) device

BACKGROUND

The Woven EndoBridge (WEB) device has Food and Drug Administration approval for treatment of wide-necked intracranial bifurcation aneurysms. The WEB device has been shown to result in adequate occlusion in bifurcation aneurysms overall, but its usefulness in the individual bifurcation locations has been evaluated separately only in few case series, which were limited by small sample sizes.

OBJECTIVE

To compare angiographic and clinical outcomes after treatment of bifurcation aneurysms at various locations, including anterior communicating artery (AComA), anterior cerebral artery (ACA) bifurcation distal to AComA, basilar tip, internal carotid artery (ICA) bifurcation, and middle cerebral artery (MCA) bifurcation aneurysms using the WEB device.

METHODS

A retrospective cohort analysis was conducted at 22 academic institutions worldwide to compare treatment outcomes of patients with intracranial bifurcation aneurysms using the WEB device. Data include patient and aneurysm characteristics, procedural details, angiographic and functional outcomes, and complications.

RESULTS

A total of 572 aneurysms were included. MCA (36%), AComA (35.7%), and basilar tip (18.9%) aneurysms were most common. The rate of adequate aneurysm occlusion was significantly higher for basilar tip (91.6%) and ICA bifurcation (96.7%) aneurysms and lower for ACA bifurcation (71.4%) and AComA (80.6%) aneurysms (p=0.04).

CONCLUSION

To our knowledge, this is the most extensive study to date that compares the treatment of different intracranial bifurcation aneurysms using the WEB device. Basilar tip and ICA bifurcation aneurysms showed significantly higher rates of aneurysm occlusion than other locations.

Unassisted and multiple microcatheter coiling of distal basilar aneurysms: Outcomes and literature review

PURPOSE

The best treatment for distal basilar artery aneurysms is controversial. We aimed to review our single-centre experience with coil embolisation of aneurysms at this location and compare it with the surgical and endovascular literature.

METHODS

Forty-two aneurysms in a distal basilar location in 42 consecutive patients (15 ruptured and 27 unruptured) were treated endovascularly from 2010 to 2015. Unassisted single and multiple microcatheter coil embolisation alone was used in all cases. We studied our immediate and long-term anatomical results, operative complications, and outcome.

RESULTS

The immediate angiographic results showed complete occlusion in 34 (81%), a neck remnant in seven (16.6%) and a residual aneurysm in one patient (2.4%). There were two thromboembolic events (4.7%) without clinical sequelae; therefore, the operative morbidity and mortality were zero.Three patients with ruptured aneurysms (7.1%) died due to complicated vasospasm. Thirty-nine patients (93%) had clinical and MR imaging follow-up (mean 32.3 months ± 18.6, range from 12 to 66 months). There was recanalization in 30.8% with a retreatment rate of 15.3% and no new bleedings. The aneurysm size was the most important predictor of early anatomical outcome and recurrence.

CONCLUSION

Unassisted and multiple microcatheter coiling is a safe treatment for distal basilar aneurysms. Early anatomical results and recurrence depend on the aneurysm size. Morbidity and mortality are lower and recurrence rates are higher in comparison with clipping or other adjunctive endovascular techniques.

Common carotid to vertebral artery bypass to facilitate endovascular treatment of a basilar artery aneurysm

Large posterior circulation intracranial aneurysms have a high risk of significant morbidity or mortality if left unmanaged. Endovascular techniques are well established as primary treatment for such aneurysms. This includes placement of endovascular flow diversion stents that result in progressive thrombosis and resolution of aneurysms. Successful stent placement is reliant on suitable cervical vascular access. We report a case of a 60-year-old male without direct vertebral artery access to a fusiform basilar artery aneurysm. Successful endovascular treatment required a novel hybrid technique utilizing a right common carotid to V3 segment vertebral arterial bypass to gain endovascular access to the aneurysm.