Microsurgical management of basilar artery apex aneurysms: a single surgeon's experience from Louisiana State University, Shreveport

Review of current treatment modalities and clinical outcome of giant saccular aneurysms of the basilar apex

Introduction

Giant aneurysms of the basilar apex represent formidable challenges as the high rupture rate of untreated lesions must be balanced against the technical complexity and potential morbidity of intervention.

Research question

Review of treatment modalities and outcomes of patients harboring giant (>2.5 cm) basilar apex saccular aneurysms, in an effort to refine treatment decision-making.

Material and methods

A systematic literature review through the PubMed and Scopus databases was performed according to the PRISMA guidelines to identify cases of giant basilar apex saccular aneurysms treated either microsurgically or endovascularly. Patients' demographics, aneurysm size, preoperative and postoperative neurologic status, angiographic and clinical outcomes as well as follow-up information were obtained.

Results

Data from 32 studies fulfilling the inclusion criteria, including 49 patients (32 treated surgically and 17 endovascularly) was obtained. Mean patient age at presentation was 51.69 years, with a male-to-female ratio of 1:2. Mean maximum aneurysm diameter was 30.57 mm. A favorable outcome (mRS 0-2) was reported on 70.6% of endovascular and 56.3% of open surgical cases. Complete aneurysm occlusion was achieved in 55.6% of the open and 23.5% of the endovascular cases. Death rate was 33% for endovascular and 15.6% for open cases; the higher mortality of endovascular treatment is mainly attributed to the mass effect from continued brainstem compression after treatment.

Discussion and conclusion

Higher rates of complete occlusion but higher morbidity are associated with microsurgery compared to endovascular modalities. Severe, clinically apparent brainstem mass effect may require decompression associated with microsurgery, when technically feasible.

How I do it: neuromonitoring-guided clipping of high-riding basilar tip aneurysm

BACKGROUND

Clipping of basilar tip aneurysms presents unique challenges due to the risk of perforator compromise and subsequent disabling stroke.

METHOD

Herein, we describe the correct trajectory of the clip applier to clip basilar tip aneurysms through an orbitozygomatic approach to prevent perforator injury and discuss management of intraoperative neuromonitoring changes.

CONCLUSION

We anticipate that this video and illustration will aid surgeons as they treat complex wide-necked basilar tip aneurysms with microsurgical clipping.

Basilar apex aneurysm systematic review: Microsurgical versus endovascular treatment

BACKGROUND

Both microsurgical and endovascular techniques continued to be treatment options for basilar apex aneurysms (BAA). We conducted a systematic review to compare both treatment options in terms of both clinical and radiological outcomes.

METHODS

The PRISMA method was used to identify related articles. Data collected from each article and the two treatment approaches were compared in terms of favorable clinical outcome and complete/near complete occlusion rate. Subgroup analysis was done based on the size and the rupture status of BAA.

RESULTS

Fifty-nine (59) and 32 articles reported a measurable clinical and radiological outcome respectively. The weighted average favorable clinical outcome was significantly higher in the endovascular group (86.4% vs 79.6%, P<0.0001), while the weighted average complete/near complete occlusion rate was significantly higher in the surgical group (92.6% vs 83.8%, P<0.0001). In the subgroup analysis, the favorable clinical outcome remained significantly higher in the endovascular group for the ruptured, unruptured and giant/large BAA (P<0.001), but not in the small BAA subgroup (P=0.26). The occlusion rate remained significantly higher in the surgical group for all subgroups (P<0.001).

CONCLUSION

Treatment of BAA remains in a trade-off between favorable clinical outcome and complete or near-complete occlusion depending on the treatment modality selected. Careful selection of cases and judicial discussion between open surgical and endovascular team is warranted for treatment optimization.

Microsurgical Management of Posterior Circulation Aneurysms: A Retrospective Study on Epidemiology, Outcomes, and Surgical Approaches

Posterior circulation aneurysms have been regarded as the most challenging for endovascular coiling and microsurgical occlusion. The role of microsurgical treatment is gradually being overlooked and diminishing in the trend of endovascular treatment. As microsurgical occlusion of posterior circulation aneurysms is decreasing, we present our relevant experience to evaluate treatment options and surgical approaches. A retrospective study was conducted in the Department of Neurosurgery of the First Affiliated Hospital of Soochow University between 2016 and 2021. Patients with posterior circulation aneurysms treated by clipping, bypass, and trapping were enrolled and followed up for at least six months. We included 50 patients carrying 53 posterior circulation aneurysms, 43 of whom had aneurysm ruptures. The posterior cerebral artery and posterior inferior cerebellar artery were the most common aneurysm locations. Direct clipping was performed in 43 patients, while bypass and trapping was performed in six patients. The retrosigmoid, far-lateral, and midline or paramedian suboccipital approaches were performed for those aneurysms in the middle and lower thirds. Aneurysms in the upper third required the lateral supraorbital approach, pterional approach, subtemporal approach, and occipital craniotomy. The lateral supraorbital approach was utilized in seven patients for aneurysms above the posterior clinoid process. Thirty-four patients recovered well with modified Rankin score 0-3 at discharge. No patient experienced aneurysm recurrence during the mean follow-up period of 3.57 years. Microsurgery clipping and bypass should be considered in conjunction with endovascular treatment as a treatment option in posterior circulation aneurysms. The lateral supraorbital approach is a feasible, safe, and simple surgical approach for aneurysms above the posterior clinoid process.

Microsurgical Management of Posterior Circulation Aneurysms: A Retrospective Study on Epidemiology, Outcomes, and Surgical Approaches

Posterior circulation aneurysms have been regarded as the most challenging for endovascular coiling and microsurgical occlusion. The role of microsurgical treatment is gradually being overlooked and diminishing in the trend of endovascular treatment. As microsurgical occlusion of posterior circulation aneurysms is decreasing, we present our relevant experience to evaluate treatment options and surgical approaches. A retrospective study was conducted in the Department of Neurosurgery of the First Affiliated Hospital of Soochow University between 2016 and 2021. Patients with posterior circulation aneurysms treated by clipping, bypass, and trapping were enrolled and followed up for at least six months. We included 50 patients carrying 53 posterior circulation aneurysms, 43 of whom had aneurysm ruptures. The posterior cerebral artery and posterior inferior cerebellar artery were the most common aneurysm locations. Direct clipping was performed in 43 patients, while bypass and trapping was performed in six patients. The retrosigmoid, far-lateral, and midline or paramedian suboccipital approaches were performed for those aneurysms in the middle and lower thirds. Aneurysms in the upper third required the lateral supraorbital approach, pterional approach, subtemporal approach, and occipital craniotomy. The lateral supraorbital approach was utilized in seven patients for aneurysms above the posterior clinoid process. Thirty-four patients recovered well with modified Rankin score 0–3 at discharge. No patient experienced aneurysm recurrence during the mean follow-up period of 3.57 years. Microsurgery clipping and bypass should be considered in conjunction with endovascular treatment as a treatment option in posterior circulation aneurysms. The lateral supraorbital approach is a feasible, safe, and simple surgical approach for aneurysms above the posterior clinoid process.

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.

Long-Term Durability and Recurrence Patterns After Endovascular Treatment for Basilar Tip Aneurysms

BACKGROUND

Treating recurrence after coil embolization of basilar tip aneurysm remains challenging even with the development of endovascular procedures. The present study evaluated long-term durability and recurrence patterns after endovascular treatment of basilar tip aneurysms.

METHODS

Data of 116 consecutive patients treated with endovascular therapy at 3 regional hospitals from 2002-2019 were retrospectively analyzed. Aneurysms were ruptured in 51 cases and unruptured in 65 cases, with a mean maximal diameter of 7.8 mm (>15 mm in 14 patients) and a mean follow-up period of 5.8 ± 4.3 years.

RESULTS

Recurrence was observed in 24 of the 116 patients (21%), and 14 patients were retreated. The 5-year recurrence-free survival rate was 75.3%. Cox proportional hazards analysis found that recurrence correlated significantly with maximal aneurysm diameter >10 mm (P = 0.001; hazard ratio: 3.95, 95% confidence interval: 1.76-8.90) and incomplete occlusion (P = 0.003; hazard ratio: 4.43, 95% confidence interval: 1.63-12.00). Recurrence pattern was classified into 3 types: neck type (9 patients), regrowth type (10 patients), and regrowth type of initially thrombosed aneurysms (3 patients). Rerupture occurred in neck type with de novo aneurysm formation adjacent to the neck (n = 3) and regrowth type with dome filling (n = 4).

CONCLUSIONS

Recurrence after coil embolization for basilar tip aneurysms is associated with large aneurysms and incomplete occlusion at initial embolization. Understanding the patterns of recurrence is useful for predicting recurrence and selecting treatment strategies.

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.

Endovascular embolization versus surgical clipping in a single surgeon series of basilar artery aneurysms: a complementary approach in the endovascular era

Background

Currently, most basilar artery aneurysms (BAAs) are treated endovascularly. Surgery remains an appropriate therapy for a subset of all intracranial aneurysms. Whether open microsurgery would be required or utilized, and to what extent, for BAAs treated by a surgeon who performs both endovascular and open procedures has not been reported.

Methods

Retrospective analysis of prospectively maintained, single-surgeon series of BAAs treated with endovascular or open surgery from the first 5 years of practice.

Results

Forty-two procedures were performed in 34 patients to treat BAAs—including aneurysms arising from basilar artery apex, trunk, and perforators. Unruptured BAAs accounted for 35/42 cases (83.3%), and the mean aneurysm diameter was 8.4 ± 5.4 mm. Endovascular coiling—including stent-assisted coiling—accounted for 26/42 (61.9%) treatments and led to complete obliteration in 76.9% of cases. Four patients in the endovascular cohort required re-treatment. Surgical clip reconstruction accounted for 16/42 (38.1%) treatments and led to complete obliteration in 88.5% of cases. Good neurologic outcome (mRS ≤ 2) was achieved in 88.5% and 75.0% of patients in endovascular and open surgical cohorts, respectively (p = 0.40). Univariate logistic regression analysis demonstrated that advanced age (OR 1.11[95% CI 1.01–1.23]) or peri-procedural adverse event (OR 85.0 [95% CI 6.5–118.9]), but not treatment modality (OR 0.39[95% CI 0.08–2.04]), was the predictor of poor neurologic outcome.

Conclusions

Complementary implementation of both endovascular and open surgery facilitates individualized treatment planning of BAAs. By leveraging strengths of both techniques, equivalent clinical outcomes and technical proficiency may be achieved with both modalities.

Neurosurgical management of aneurysms of the vertebrobasilar system: increasing indications for endovascular therapy with a continued role for open microneurosurgery

Aneurysms of the vertebrobasilar system remain among the most challenging subsets of aneurysms to treat with an open surgical approach. Since Charles Drake's pioneering work in the 1960s, several advances in microsurgical techniques have improved outcomes and feasibility in the open surgical management of these aneurysms. In parallel, the field of endovascular neurosurgery has provided several safe and effective treatment options. Multiple trials have suggested that endovascular therapy for aneurysms of the vertebrobasilar system is superior to open surgical management in most cases. In some instances, however, open surgical management likely represents a more effective and durable option relative to endovascular therapy. Therefore, continued training of future cerebrovascular specialists in open surgery of vertebrobasilar aneurysms remains crucial. With widespread utilization of endovascular techniques, however, proper exposure of trainees to such aneurysms is growing increasingly difficult. In this review, we discuss the recent advances in the endovascular management of vertebrobasilar aneurysms while also emphasizing the continued importance of open microneurosurgery in such cases.

Posterior Circulation Aneurysms: A Critical Appraisal of a Surgical Series in Endovascular Era

The advent of the endovascular era has apparently decreased the role of microneurosurgery for many of the posterior circulation aneurysms. This study consists of a critical appraisal of a retrospective surgical series regarding posterior circulation aneurysms, targeted to define whether microneurosurgery still has a role for some of these. In 28 years, 157 aneurysms were surgically treated, 98 of which ruptured. The Average patient age was 56.7 ± 14.2 years, while in hemorrhagic cases, the mean Hunt-Hess score was 2.17 ± 0.8. Basilar tip, vertebral artery and proximal posterior inferior cerebellar artery were the most frequently involved sites. The treatment consisted of 128 clippings, 19 trappings, 7 wrappings, and 3 bypasses. A total exclusion was achieved in 88.5% of the aneurysms. An average follow-up of 67.1 ± 61.3 months proved no recurrences. The best results were observed in patients <65 years old who harbored small-to-regular aneurysms of the basilar tip, distal cerebellar arteries, or vertebral artery.Clipping proved to be a definitive and durable treatment for a large part of posterior circulation aneurysms, whereas bypass allows for treating aneurysms not amenable for coiling, stenting, or clipping. The present study confirms that microneurosurgery continues to have a paramount role within neurovascular pathology.

Endovascular Temporary Balloon Occlusion for Microsurgical Clipping of Posterior Circulation Aneurysms

Based on the relationship between the posterior clinoid process and the basilar artery (BA) apex it may be difficult to obtain proximal control of the BA using temporary clips. Endovascular BA temporary balloon occlusion (TBO) can reduce aneurysm sac pressure, facilitate dissection/clipping, and finally lower the risk of intraoperative rupture. We present our experience with TBO during aneurysm clipping of posterior circulation aneurysms within the setting of a hybrid operating room (hOR). We report one case each of a basilar tip, posterior cerebral artery, and superior cerebellar artery aneurysm that underwent surgical occlusion under TBO within an hOR. Surgical exposure of the BA was achieved with a pterional approach and selective anterior and posterior clinoidectomy. Intraoperative digital subtraction angiography (iDSA) was performed prior, during, and after aneurysm occlusion. Two patients presented with subarachnoid hemorrhage and one patient presented with an unruptured aneurysm. The intraluminal balloon was inserted through the femoral artery and inflated in the BA after craniotomy to allow further dissection of the parent vessel and branches needed for the preparation of the aneurysm neck. No complications during balloon inflation and aneurysm dissection occurred. Intraoperative aneurysm rupture prior to clipping did not occur. The duration of TBO varied between 9 and 11 min. Small neck aneurysm remnants were present in two cases (BA and PCA). Two patients recovered well with a GOS 5 after surgery and one patient died due to complications unrelated to surgery. Intraoperative TBO within the hOR is a feasible and safe procedure with no additional morbidity when using a standardized protocol and setting. No relevant side effects or intraoperative complications were present in this series. In addition, iDSA in an hOR facilitates the evaluation of the surgical result and 3D reconstructions provide documentation of potential aneurysm remnants for future follow-up.

Adenosine-Induced transient asystole during surgical treatment of basilar artery aneurysms

Aim

To evaluate the safety and efficacy of adenosine-induced transient asystole (AITA) during surgery for basilar artery aneurysms.

Materials and Methods

All the patients with basilar artery aneurysms operated using AITA at our institute during two years period (August 2013-July 2015) were included in this study.

Results

Adenosine was used in 11 patients with 13 basilar artery aneurysms. Seven of these aneurysms were basilar bifurcation aneurysms, four were basilar-superior cerebellar artery junction aneurysms, and two were distal basilar trunk aneurysms. The indications for AITA were narrow corridor for placement of temporary clip in 11 aneurysms, intraop rupture in 1 aneurysm, and circumferential dissection of a large aneurysm in 1. The mean dose of adenosine used for inducing asystole was 19.4 mg (range: 15-30 mg) and the mean total dose of adenosine used was 40.6 mg (range: 18-90 mg). A mean of 2 (range: 1-5) AITAs were required during surgical treatment of these aneurysms. The mean duration of a systole was 27 s (range: 9-76 s). There were no complications related to AITA in these patients except for transient rebound hypertension in one patient. Check angiogram revealed complete obliteration of 11 aneurysms and small residual neck in 2 aneurysms. Modified Rankin Scale at three months of follow-up was 0 in seven patients, 1 in two patients, 4 in one patient, and 6 in one patient.

Conclusion

AITA during surgical management of basilar artery aneurysms is a safe and effective technique and has an important role during surgery for these aneurysms.

Can sectioning the posterior communicating artery be predicted with computed tomography angiography in the microsurgical clipping of basilar apex aneurysms?

BACKGROUND

Microsurgical clipping is a viable option for managing high-riding basilar apex aneurysms (BAXs) using a transsylvian approach. Cutting the posterior communicating artery (PCoA) at the perforator-free zone provides sufficient exposure of BAX, although it is not always safe. The aim was to qualitatively predict sectioning of the interfering PCoA by using preoperative computed tomographic angiography (CTA).

METHODS

A virtual trajectory from the lesser sphenoid wing to the neck of the aneurysm was simulated on CTA in 19 consecutive patients operated on BAX aneurysms from 2013 to 2018. The angles on CTA resembled the typical view through the extended pterional craniotomy. Next, the ipsilateral PCoA was tracked from the internal carotid to its end at the posterior cerebral artery in the trajectory.

RESULTS

The opticocarotid and carotid-oculomotor window served as the corridors for entering the interpeduncular fossa in 16 patients (84.2%) and in 3 patients (15.8%), respectively. The PCoA was intentionally cut during nine surgeries and preserved in 10 of them. The PCoA was cut more often when positioned toward the cranial base and more medially in the corridor; both the Kernel density analysis and the data points representing the position of the PCoA supported this finding (p < 0.01). The CTA-based position of either ends of the PCoA in the trajectory did not differ between cut and not-cut groups (p = 0.19-0.96). Aneurysm projection, rupture, size, PCoA diameter, length, and other distances on CTA were not related to the sectioning of PCoA (p > 0.05).

CONCLUSIONS

The probability of PCoA sectioning is higher when the PCoA is positioned medially and closer to the cranial base. If the anatomical course of the PCoA is recognized beforehand, it can contraindicate surgery. Preoperative CTA-based planning facilitates the surgery of BAX aneurysms. Therefore, CTA can make microsurgical clipping planning more predictable for the neurosurgeon and safer for the patient.

Anterior Temporal Approach and Clipping of a High-Riding Basilar Tip Aneurysm: Case Report and Review of the Surgical Technique

Basilar apex aneurysms constitute 5%–8% of all intracranial aneurysms. Microsurgical clipping of basilar tip aneurysms is still advocated for as it is safe, especially for unruptured basilar tip aneurysms which have a low risk of postoperative mortality or morbidity. Careful patient preparation is needed preoperatively because the risk of intraoperative rupture is significant. Good surgical techniques should be applied. The skill will need to be preserved as endovascular surgery becomes more popular. This is a case of basilar tip aneurysm managed by clipping through the anterior temporal approach, followed by a review of the literature.

Clinical outcomes and cost-effectiveness analysis for the treatment of basilar tip aneurysms

Background

Endovascular treatment of basilar tip aneurysms is less invasive than microsurgical clipping, but requires closer follow-up.

Objective

To characterize the additional costs associated with endovascular treatment of basilar tip aneurysms rather than microsurgical clipping.

Materials and methods

We obtained clinical records and billing information for 141 basilar tip aneurysms treated with clip ligation (n=48) or endovascular embolization (n=93). Costs included direct and indirect costs associated with index hospitalization, as well as re-treatments, follow-up visits, imaging studies, rehabilitation, and disability. Effectiveness of treatment was quantified by converting functional outcomes (modified Rankin Scale (mRS) score) into quality-adjusted life-years (QALYs). Cost-effectiveness was performed using cost/QALY ratios.

Results

Average index hospitalization costs were significantly higher for patients with unruptured aneurysms treated with clip ligation ($71 400 ± $47 100) compared with coil embolization ($33 500 ± $22 600), balloon-assisted coiling ($26 200 ± $11 600), and stent-assisted coiling ($38 500 ± $20 900). Multivariate predictors for higher index hospitalization cost included vasospasm requiring endovascular intervention, placement of a ventriculoperitoneal shunt, longer length of stay, larger aneurysm neck and width, higher Hunt-Hess grade, and treatment-associated complications. At 1 year, endovascular treatment was associated with lower cost/QALY than clip ligation in unruptured aneurysms ($52 000/QALY vs $137 000/QALY, respectively, p=0.006), but comparable rates in ruptured aneurysms ($193 000/QALY vs $233 000/QALY, p=0.277). Multivariate predictors for higher cost/QALY included worse mRS score at discharge, procedural complications, and larger aneurysm width.

Conclusions

Coil embolization of basilar tip aneurysms is associated with a lower cost/QALY. This effect is sustained during follow-up. Clinical condition at discharge is the most significant predictor of overall cost/QALY at 1 year.

Assessment of the endoscopic endonasal approach to the basilar apex region for aneurysm clipping

OBJECTIVE

The expanded endoscopic endonasal approach (EEA) has shown promising results in treatment of midline skull base lesions. Several case reports exist on the utilization of the EEA for treatment of aneurysms. However, a comparison of this approach with the classic transcranial orbitozygomatic approach to the basilar apex (BAX) region is missing.The present study summarizes the results of a series of cadaveric surgical simulations for assessment of the EEA to the BAX region for aneurysm clipping and its comparison with the transcranial orbitozygomatic approach as one of the most common approaches used to treat BAX aneurysms.

METHODS

Fifteen cadaveric specimens underwent bilateral orbitozygomatic craniotomies as well as an EEA (first without a pituitary transposition [PT] and then with a PT) to expose the BAX. The following variables were measured, recorded, and compared between the orbitozygomatic approach and the EEA: 1) number of perforating arteries counted on bilateral posterior cerebral arteries (PCAs); 2) exposure and clipping lengths of the PCAs, superior cerebellar arteries (SCAs), and proximal basilar artery; and 3) surgical area of exposure in the BAX region.

RESULTS

Except for the proximal basilar artery exposure and clipping, the orbitozygomatic approach provided statistically significantly greater values for vascular exposure and control in the BAX region (i.e., exposure and clipping of ipsilateral and contralateral SCAs and PCAs). The EEA with PT was significantly better in exposing and clipping bilateral PCAs compared to EEA without a PT, but not in terms of other measured variables. The surgical area of exposure and PCA perforator counts were not significantly different between the 3 approaches. The EEA provided better exposure and control if the BAX was located ≥ 4 mm inferior to the dorsum sellae.

CONCLUSIONS

For BAX aneurysms located in the retrosellar area, PT is usually required to obtain improved exposure and control for the bilateral PCAs. However, the transcranial approach is generally superior to both endoscopic approaches for accessing the BAX region. Considering the superior exposure of the proximal basilar artery obtained with the EEA, it could be a viable option when surgical treatment is considered for a low-lying BAX or mid-basilar trunk aneurysms (≥ 4 mm inferior to dorsum sellae).

Concomitant ruptured anterior circulation and unruptured posterior circulation aneurysms: Treatment strategy and review of literature

Basilar artery apex or bifurcation is the most common location for aneurysms arising from posterior cerebral circulation. Reports of unruptured aneurysms of the basilar bifurcation associated with ruptured anterior circulation aneurysms are rare. The presence of multiple intracranial aneurysms poses a significantly high risk to management than a single aneurysm due several factors involved. Surgical management is considered the best treatment modality for most aneurysmal types and location with quite a few limitations when applicable. Authors have conducted a literature review of anterior and posterior circulation concomitant aneurysms and report their own experience with a case of anterior communicating artery blister type aneurysmal rupture presented with the symptoms and signs of subarachnoid hemorrhage concomitant with an unruptured basilar artery bifurcation aneurysm. Moreover, the anomalous origin of thalamoperforators at the basilar apex instead of the posterior cerebral artery makes it reasonably challenging for the microsurgical clipping. Discussed is the clinical presentation, radiological studies obtained, surgical approach utilized with an adequate exposure of the entire circle of Willis as well as the critical decision making when managing these challenging cases.

Microsurgical Clipping of Basilar Apex Aneurysms: A Systematic Historical Review of Approaches and their Results

OBJECTIVE

Neck clipping remains a valuable treatment option for basilar apex aneurysms, especially in those with complex morphology, such as incorporation of branching vessels or large size, and young patient age. Several approaches have proved to give effective exposure for various types of lesion morphologies. Our historic literature review from 1976 to the present systematically compares the outcomes and complications of the key surgical approaches in the treatment of basilar apex aneurysms.

METHODS

We searched PubMed for articles with at least 5 patients, data on neurologic outcome, and procedure-associated complications for the following approaches: pterional or orbitozygomatic transsylvian, subtemporal (with or without zygomatic osteotomy), pretemporal (with or without transcavernous extension), and transpetrous. n-Weighted averages for clinical outcome, aneurysm occlusion rates, morbidity, mortality, and aneurysm morphology were compared.

RESULTS

Of 35 articles selected, 2041 patients with 722 ruptured aneurysms underwent microsurgery, including 1131 transsylvian, 241 pretemporal, 375 subtemporal, and 17 transpetrous approaches. Comparing these 4 approaches in n-weighted averages, respectively, we noted good neurologic outcomes (81%, 85%, 81%, and 58%), surgical morbidity (14%, 10%, 34%, and 53%), surgical mortality (4%, 1%, 0, and 1%), and complete occlusion rates (95%, 94%, 86%, and 75%).

CONCLUSIONS

Transsylvian, pretemporal, and subtemporal approaches showed favorable neurologic outcomes at similar rates and were applied for aneurysms located between -1mm and +7mm in relation to the posterior clinoid process. The pretemporal approach was preferably applied to large and giant aneurysms with good outcome; the transsylvian approach was most frequently used for ruptured aneurysms.

Wide-neck bifurcation aneurysms of the middle cerebral artery and basilar apex treated by endovascular techniques: a multicentre, core lab adjudicated study evaluating safety and durability of occlusion (BRANCH)

Background and purpose

BRANCH (wide-neck bifurcation aneurysms of the middle cerebral artery and basilar apex treated by endovascular techniques) is a multicentre, retrospective study comparing core lab evaluation of angiographic outcomes with self-reported outcomes.

Materials and methods

Consecutive patients were enrolled from 10 US centres, aged between 18 and 85 with unruptured wide-neck middle cerebral artery (MCA) or basilar apex aneurysms treated endovascularly. Patient demographics, aneurysm morphology, procedural information, mortality and morbidity data and core lab and self-reported modified Raymond Roy (RR) outcomes were obtained.

Results

115 patients met inclusion criteria. Intervention-related mortality and significant morbidity rates were 1.7% (2/115) and 5.8% (6/103) respectively. Core lab adjudicated RR1 and 2 occlusion rates at follow-up were 30.6% and 32.4% respectively. The retreatment rate within the follow-up window was 10/115 (8.7%) and in stent stenosis at follow-up was 5/63 (7.9%). Self-reporting shows a statistically significant direction to angiographic RR one outcomes at follow-up compared with core lab evaluation, with OR 1.75 (95% CI 1.08 to 2.83).

Conclusion

Endovascular treatment of wide-neck MCA and basilar apex aneurysms resulted in a core lab adjudicated RR1 occlusion rate of 30.6%. Self-reported results at follow-up favour better angiographic outcomes, with OR 1.75 (95% CI 1.08 to 2.83). These data demonstrate the need for novel endovascular devices specifically designed to treat complex intracranial aneurysms, as well as the importance of core lab adjudication in assessing outcomes in such a trial.

Should we still consider clips for basilar apex aneurysms? A critical appraisal of the literature

Background:

Basilar apex aneurysms constitute 5–8% of all intracranial aneurysms, and their treatment remains challenging for both microsurgical and endovascular approaches. The perceived drawback of the microsurgical approach is its invasiveness leading to increased surgical morbidity. However, many high-volume centers have shown excellent clinical results with better occlusion rates compared to endovascular treatment. With endovascular therapy taking a larger role in the management of cerebral aneurysms, the future role of microsurgery for basilar apex aneurysm treatment is unclear.

Methods:

We performed a literature search to review the microsurgical and endovascular outcomes for basilar apex aneurysms.

Results:

Many studies have examined the efficacy of microsurgical and endovascular treatment for intracranial aneurysms, including large randomized trials such as ISAT and BRAT, prospective observational series such as ISUIA, and many single-center retrospective reviews. The recruitment number for posterior circulation aneurysms, specifically for basilar apex aneurysms, was limited in most prospective trials, thus failing to offer clear guidance on basilar apex aneurysm treatment. Recent single-center series report good clinical outcomes between 57–92% for surgical series and 73–96% in endovascular series. The durability of aneurysm occlusion remains superior in surgical cases. The techniques and devices in endovascular treatment have improved treatment aneurysm occlusion rates but more follow-up is needed to confirm long-term durability.

Conclusions:

Both microsurgical and endovascular approaches should be complementing each other to treat basilar apex aneurysms. Although endovascular therapy has taken a larger role in the treatment of basilar apex aneurysms, many indications still exist for the use of microsurgery. Advancements in microsurgical techniques and good case selection will allow for acceptably low morbidity after surgical treatment while maintaining its superior durability.

Microsurgical Treatment for Complex Basilar Artery Aneurysms with Long-Term Follow-Up in a Series of 35 Cases

BACKGROUND

There has been a massive shift in the balance toward endovascular therapy for basilar artery (BA) aneurysms in the modern era.

METHODS

We retrospectively reviewed clinical and radiologic data from patients with BA aneurysms who were treated in a single medical center during a 10-year period from August 2006 to May 2016.

RESULTS

Thirty-five consecutive patients with 46 aneurysms during the 10-year period were included. The rate of complete aneurysm occlusion in 35 cases using a 1-stage operation was 58.8% (20/34). The graft patency rates of 13 bypass surgeries were 84.6% (11/13) within 1 week and 69.2% (9/13) at 3 months after surgery. The cut flow index for all bypass cases was 0.79. The overall survival was 94% at discharge (2 patients died). The 3-month outcome was favorable (modified Rankin Scale score 0-2) for 27 patients (77.1%) and poor (modified Rankin Scale score 3-5) for 5 patients (14.2%), and 3 patients died (8.6%). The survival for patients with BA apex aneurysms was higher than the survival observed for patients with BA trunk/vertebrobasilar junction aneurysms.

CONCLUSIONS

Microsurgical treatments for BA aneurysms can be effective, with good patient outcomes in the early stage after operation. Patients with wide-necked, fusiform, or dolichoectatic aneurysms seem to exclude the aneurysm, preventing unnecessary retreatments with bypass techniques. The potential for a poor prognosis of patients with BA trunk/vertebrobasilar junction aneurysms was higher than that for patients with basilar apex aneurysms who presented with unfavorable subsequent events.

Comparison of endovascular and microsurgical management of 208 basilar apex aneurysms

OBJECTIVE

The deep and difficult-to-reach location of basilar apex aneurysms, along with their location near critical adjacent perforating arteries, has rendered the perception that microsurgical treatment of these aneurysms is risky. As a result, these aneurysms are considered more suitable for treatment by endovascular intervention. The authors attempt to compare the immediate and long-term outcomes of microsurgery versus endovascular therapy for this aneurysm subtype.

METHODS

A prospectively maintained database of 208 consecutive patients treated for basilar apex aneurysms between 2000 and 2012 was reviewed. In this group, 161 patients underwent endovascular treatment and 47 were managed microsurgically. The corresponding records were analyzed for presenting characteristics, postoperative complications, discharge status, and Glasgow Outcome Scale (GOS) scores up to 1 year after treatment and compared using chi-square and Student t-tests.

RESULTS

Among these 208 aneurysms, 116 (56%) were ruptured, including 92 (57%) and 24 (51%) of the endovascularly and microsurgically managed aneurysms, respectively. The average Hunt and Hess grade was 2.4 (2.4 in the endovascular group and 2.2 in the microsurgical group; p = 0.472). Postoperative complications of cranial nerve deficits and hemiparesis were more common in patients treated microsurgically than endovascularly (55.3% vs 16.2%, p < 0.05; and 27.7% vs 10.6%, p < 0.05, respectively). However, aneurysm remnants and need for retreatment were more common in the endovascular than the microsurgical group (41.3% vs 2.3%, p < 0.05; and 10.6% vs 0.0%, p < 0.05, respectively). Stent placement significantly reduced the need for retreatment. Rehemorrhage rates and average GOS score at discharge and 1 year after treatment were not statistically different between the two treatment groups.

CONCLUSIONS

Patients with basilar apex aneurysms were significantly more likely to be treated via endovascular management, but compared with those treated microsurgically, they had higher rates of recurrence and need for retreatment. The current study did not detect an overall difference in outcomes at discharge and 1 year after either treatment modality. Therefore, in a select group of patients, microsurgical treatment continues to play an important role.

Microsurgical treatment of basilar tip aneurysms: is it still acceptable?

OBJECTIVE

Basilar tip aneurysms (BTAs) have a complex anatomy, making them difficult to treat. We describe our surgical results for BTAs.

METHODS

From 2004 to 2015 (12 years), a total of 25 small BTAs and two giant BTAs were treated in the Hospital do Servidor Público Estadual de São Paulo.

RESULTS

In 23 patients harboring aneurysms positioned anteriorly or straight, all aneurysms were clipped (complete exclusion in all on follow-up angiography). In two patients with posteriorly positioned aneurysms, there was residual neck. All patients submitted to surgical treatment of small aneurysms presented with late Glasgow Outcome Scale scores of 4 or 5. Two patients with giant aneurysms died.

CONCLUSION

Surgical treatment of these lesions may be accomplished with quite high success rates and low morbidity.

Endovascular treatment of cerebral aneurysms using the Woven EndoBridge technique in a single center: preliminary results

OBJECTIVE The Woven EndoBridge (WEB) is an innovative new technique for securing cerebral aneurysms. It is designed particularly for wide-necked bifurcation aneurysms that otherwise would be difficult to treat. There is a paucity of follow-up data in the literature due to the novelty of this technique. The authors reviewed their data from cases involving patients treated at Leeds General Infirmary with the WEB device. They assessed the safety and complication risk associated with the device and clinical and radiological follow-up outcomes in their patients. This is, to their knowledge, the first publication to include the new single-layer sphere device (WEB SLS) in addition to the original dual-layer (WEB DL) and the (nonsphere) single-layer (WEB SL) devices. METHODS Data from 22 patients who underwent 25 WEB treatments were analyzed. Of the 25 WEB procedures, 3 were performed on an acute basis, 1 was performed on a semiacute basis, and the remaining 21 were elective. A novel 6-point scoring system called the Leeds WEB aneurysm occlusion scale was created to ensure accurate assessment based on the morphology of the WEB device. Outcome was assessed at follow-up by MR angiography with or without digital subtraction angiography and the modified Rankin Scale (mRS). RESULTS Deployment of the WEB device was successful in 22 (88%) of 25 procedures; 3 (12%) of the attempts at WEB treatment were abandoned. One of the patients in whom treatment was abandoned underwent a successful second attempt. Immediately after the 22 procedures with successful deployment, 4 (18%) of the patients had a complete occlusion of the aneurysm and WEB device; 10 (45%) had varying degrees of occlusion within the WEB device but no aneurysm neck or remnant; 3 (14%) had a neck remnant; and 5 (23%) had an aneurysm remnant. Of the patients with an aneurysm remnant, 1 had a complete aneurysm occlusion at ≥ 3-months follow-up. In total, 6 (27%) patients had a residual aneurysm at ≥ 3-months radiological follow-up. One of these patients was admitted with hydrocephalus secondary to a recurrent aneurysm and later received a second WEB treatment with additional coiling. Only 1 patient developed new neurological symptoms. This patient went from an mRS score of 0 to a score of 1 and had radiological evidence of a thromboembolic event. Two patients showed radiological evidence of a new thromboembolic event on follow-up MRI but were clinically asymptomatic. CONCLUSIONS The WEB has shown itself to be a promising new device with the potential to increase the scope of treatment for difficult wide-necked bifurcation aneurysms. The technique is safe, and short-term results show effective occlusion of complex aneurysms with minimal complications associated with the procedure. Long-term efficacy, however, still needs to be assessed.

A New Window for the Treatment of Posterior Cerebral Artery, Superior Cerebellar Artery, and Basilar Apex Aneurysm: The Expanded Endoscopic Endonasal Approach

OBJECTIVE

To explore the feasibility of an endoscopic endonasal transclival approach to treat aneurysms arising in the basilar apex, posterior cerebral arteries, and superior cerebellar arteries.

STUDY DESIGN

Cadaveric anatomical study.

PARTICIPANTS

Fifteen cadaveric specimens.

MAIN OUTCOME MEASURES

Degree of surgical exposure of each artery attained, distance from the nasal vestibule to these three arteries, and feasibility of clipping these vessels using standard vascular clip applicators.

RESULTS

Both posterior cerebral arteries were exposed, 0.67 cm (standard deviation [SD]: 0.2) on the right side and 0.59 cm (SD: 0.2) on the left side. Both right and left superior cerebral arteries were exposed, 0.6 cm (SD: 0.2) and 0.7 cm (SD: 0.3), respectively. The length of the basilar artery exposed was 2.6 cm (SD: 0.3). The distance from the nasal vestibule to the posterior cerebral artery, superior cerebellar artery, and basilar apex was 10 cm with an SD of ± 0.7, 0.6, and 0.8 cm, respectively. We were able to apply clips on each of these three vessels with a minimal alteration of surrounding normal tissue.

CONCLUSION

The endoscopic endonasal transclival approach represents a potentially feasible surgical corridor to treat aneurysms arising from these vessels.

Factors Determining Surgical Approaches to Basilar Bifurcation Aneurysms and Its Surgical Outcomes

BACKGROUND:

The basilar bifurcation aneurysm (BBA) is still considered to be one of the most challenging aneurysms for micro- and endovascular surgery. Classic surgical approaches, such as subtemporal, lateral supraorbital (LSO), and modified presigmoid, are still reliable and effective.

OBJECTIVE:

To analyze the clinical and radiological factors that affect the selection of these classic surgical approaches and their outcomes.

METHODS:

A retrospective analysis was conducted on the clinical and radiological data from computed tomographic angiography of BBA that have been clipped in the Department of Neurosurgery of Helsinki University Central Hospital between 2004 and 2014. Statistical analyses were performed using parametric and nonparametric tests where values were considered significant below P = .05.

RESULTS:

One hundred four patients with BBA underwent surgical clipping in our department between 2004 and 2014. Eight patients were excluded from the study because of incomplete preoperative radiological evaluations, leaving 96 patients for further analysis. Multiple aneurysm clipping, mean basilar bifurcation angle, and aneurysm neck distance from posterior clinoid process were shown to be factors that determine the surgical approach. Unfavorable outcome is strongly associated with poor Hunt-Hess grade on admission, distance from aneurysm neck (the posterior clinoid process), thrombosis, and dome size.

CONCLUSION:

Microsurgery for BBA clipping can be performed safely with simple surgical approaches: subtemporal and LSO. There are several factors determining the approach selected. Poor patient outcome in BBA was highly associated with poor preoperative clinical grade and large size of aneurysm dome.