Endovascular treatment of proximal and distal posterior inferior cerebellar artery aneurysms

Navigating Complexity: A Comprehensive Approach to Middle Cerebral Artery Aneurysms

Background: The concept of aneurysm "complexity" has undergone significant changes in recent years, with advancements in endovascular treatments. However, surgical clipping remains a relevant option for middle cerebral artery (MCA) aneurysms. Hence, the classical criteria used to define surgically complex MCA aneurysms require updating. Our objective is to review our institutional series, considering the impacts of various complexity features, and provide a treatment strategy algorithm. Methods: We conducted a retrospective review of our institutional experience with "complex MCA" aneurysms and analyzed single aneurysmal-related factors influencing treatment decisions. Results: We identified 14 complex cases, each exhibiting at least two complexity criteria, including fusiform shape (57%), large size (35%), giant size (21%), vessel branching from the sac (50%), intrasaccular thrombi (35%), and previous clipping/coiling (14%). In 92% of cases, the aneurysm had a wide neck, and 28% exhibited tortuosity or stenosis of proximal vessels. Conclusions: The optimal management of complex MCA aneurysms depends on a decision-making algorithm that considers various complexity criteria. In a modern medical setting, this process helps clarify the choice of treatment strategy, which should be tailored to factors such as aneurysm morphology and patient characteristics, including a combination of endovascular and surgical techniques.

Flow Diversion for the Treatment of Posterior Inferior Cerebellar Aneurysms: A Novel Classification of Posterior Inferior Cerebellar Artery Origin

BACKGROUND AND OBJECTIVES

Flow diversion (FD) for posterior circulation aneurysms, such as proximal posterior inferior cerebellar artery (PICA) aneurysms, remains "off-label" and controversial. Although there are reports of using FD in the vertebral artery (VA) to treat PICA aneurysms, the differences between structural PICA-origin variants have not been explored. We analyzed PICA aneurysms treated with FD, assessed radiographic and clinical outcomes, and presented a novel classification of the PICA origin in relationship to aneurysm anatomy.

METHODS

We performed a retrospective study of prospective data for intracranial aneurysms treated with FD at a major academic institution from 2013 to 2022. Proximal PICA aneurysms that underwent FD placement in the V4 segment of the vertebral artery were included for analysis. A literature review was performed on PubMed to evaluate previously published cases. The PICA origin was characterized by 4 distinct subtypes. Type 1 describes the PICA originating adjacent/separate to the aneurysm neck, Type 2 with the PICA originating from the aneurysm neck, Type 3 with the PICA originating from the aneurysm dome, and Type 4 (True PICA aneurysm) with the aneurysm located proximally on PICA, distal to the PICA-VA junction.

RESULTS

Thirteen proximal PICA aneurysms were identified and included in the analysis. Patients were primarily female (76.9%), with a median age of 62 years. The aneurysm median maximum diameter was 5.8 mm. From the total sample (institutional and literature review cases), type 1 had a 100% complete and near-complete occlusion rate, type 2 had 75.0%, type 3 had 88.9%, and type 4 had 75%. The overall complete and near-complete occlusion rate was 83.3% (20/24).

CONCLUSION

FD in the V4 VA segment is an effective way to treat proximal PICA aneurysms. Exploring the relationship between PICA origin is a helpful method in predicting occlusion rates for proximal PICA aneurysms and may lead to improved treatment considerations.

Microsurgical and endovascular treatment of posterior inferior cerebellar artery aneurysms: a systematic review and meta-analysis

INTRODUCTION

Posterior inferior cerebellar artery (PICA) aneurysms are uncommon vascular lesions of the posterior fossa. In addition to aneurysmal morphology, structural anatomic considerations may confer additional procedural risk, and as a result there is currently no consensus as to whether a surgical or endovascular approach offers greater safety and efficacy for patients.

EVIDENCE ACQUISITION

We systematically examined peer-reviewed literature describing PICA aneurysm treatment planning from January 2000 to May 2021 using the PRISMA methodology. A meta-analysis of proportions was performed. Certainty of the evidence was assessed using the GRADE approach.

EVIDENCE SYNTHESIS

Fifty-eight studies including 1673 PICA aneurysms were analyzed. Overall treatment occlusion rate was 97% (95% confidence interval [CI]: 93-100%) for surgery and 85% (95% CI: 78-92%) for endovascular therapy. The recurrence rate was 6% in the endovascular group and 1% for surgery. Overall morbidity and mortality were 16% and 7%, respectively. Intraoperative complications occurred in 9% of the surgical patients.

CONCLUSIONS

Despite a large body of literature, analysis indicates that 62% of studies had moderate or serious risk of bias, suggesting very-low certainty results. Therefore, treatment via either approach should be determined on a case-by-case basis and according to institutional experience.

Kissing Aneurysms of the Posterior Inferior Cerebellar Artery Treated by Anchor Coil Technique and Stenting from the Contralateral Side: A Case Report

Kissing aneurysms refer to the condition in which two cerebral aneurysms with separate necks are in contact with each other. At present, there is scarce information on kissing aneurysms occurring near the vertebral artery (VA)-posterior inferior cerebellar artery (PICA). We report the first case of VA-PICA and nonbranched PICA kissing aneurysms, which were successfully treated with contralateral stenting after the anchor coil technique using two microcatheters. A 64-year-old woman was diagnosed with a left VA-PICA aneurysm (5.5 mm) and an adjacent small PICA aneurysm (2.5 mm) with the aneurysmal walls in close contact. For stenting, microcatheters were navigated to the PICA from the contralateral side, and framing coils for the anchor were placed into each aneurysm from the ipsilateral side. Next, a Neuroform Atlas stent was deployed from the PICA to the distal side of the VA, and coiling was completed using the jailing technique. The patient had a good postoperative course, and a left vertebral angiogram revealed complete occlusion of both aneurysms after 6 months. Adequate surgical planning and application of an appropriate stent-assisted coil embolization technique contributed to the success of the procedure in this rare case.

Endovascular treatment of posterior inferior cerebellar artery trunk aneurysm

BACKGROUND

The posterior inferior cerebellar artery (PICA) generally originates from the vertebral artery (VA) and is the most complex cerebellar artery. Aneurysms can occur at any site along the PICA trunk. Although most PICA aneurysms are located at the VA-PICA junction, a small proportion is located at the PICA trunk. Endovascular treatment (EVT) of aneurysms in the PICA trunk may be difficult and complex.

METHODS

We performed a review to expound upon EVT of PICA trunk aneurysms.

RESULTS

The PICA can be divided into five segments (p1-5); the p1-3 segments are proximal segments, and the p4-5 segments are distal segments. Most PICA trunk aneurysms are dissecting aneurysms. Sometimes, the PICA can give rise to flow-related aneurysms in association with cerebellar arteriovenous malformations. Most aneurysms of the PICA trunk require aggressive treatment, especially those that have ruptured. Currently, the EVT mainly includes selective coiling with/without stent assistance and parent artery occlusion. Recently, some new devices, such as flow diversion and Barricade and Kaneka ED coils, can be used to treat PICA trunk aneurysms. The risk of complications with EVT seems to be higher; however, most complications are only transient or mild, and some are even clinically silent. In addition, open surgery is still an important option.

CONCLUSION

For PICA trunk aneurysms, the treatment choice should be assessed on a case-by-case basis. The rate of permanent morbidity of the EVT is low. EVT is an effective method for treating PICA trunk aneurysms.

Pipeline for the treatment of distal cerebral circulation aneurysms: A multicenter study focusing on periprocedural Complications

BACKGROUND AND AIM

Distal cerebral circulation aneurysms (DCCAs) remain treatment challenges for neurointervention. The off-label use of the pipeline embolization device (PED) for these aneurysms remains controversial. This study aimed to evaluate the safety and efficacy of PED for DCCAs in a multicenter cohort of patients.

METHODS

Between March 2016 and June 2021, we retrospectively analyzed the neurointerventional data on the clinical and radiological records of all patients undergoing PED treatment of DCCAs at three medical centers.

RESULTS

A total of 53 consecutive patients with 53 DCCAs were treated with PED. The mean aneurysm size was 12.3 ± 5.7 mm. In total, 75.4% (40/53) were fusiform and 24.5% (13/53) were saccular. Of these, 17.0% (9/53) were recurrent aneurysms that were previously treated with endovascular or microsurgical approaches. The technical success rate was 100%, among which 81.1% (43/53) procedures were completed with a single PED, and the rest (10/53, 18.8%) required telescoping with two devices. Angiographic follow-up data were available for 51 patients, with a median follow-up time of 12 months. At the latest follow-up, 46/51 (90.2%) aneurysms showed complete obliteration, and 4/51 (7.8%) showed reduced filling. Periprocedural complications such as hemorrhage were observed in two patients with MCA aneurysms (3.8%, 2/53), and ischemic events occurred in six patients (11.3%, 6/53). The overall mortality and morbidity rates were 7% (4/53).

CONCLUSIONS

PED is a viable option for treating DCCAs, especially for recurrent aneurysms. Coverage of bifurcation branches and perforator may increase the risk of complications.

Treatment of Proximal Posterior Inferior Cerebellar Artery Aneurysms by Intrasaccular Flow Disruption: A Multicenter Experience

BACKGROUND AND PURPOSE

Treatment of PICA aneurysms can be technically challenging by either surgical or endovascular means. Our aim was to report our preliminary experience with intrasaccular flow disruption using the Woven EndoBridge (WEB) for the treatment of proximal PICA aneurysms.

MATERIALS AND METHODS

Sixteen PICA aneurysms treated with the WEB at 3 institutions were retrospectively reviewed. Baseline patient and aneurysm characteristics, procedural specifics, clinical outcomes, and angiographic results were evaluated.

RESULTS

All aneurysms were located at the proximal, anteromedullary segment of the PICA. Seven aneurysms were ruptured. The median aneurysm size was 3.9 mm (range, 2-12 mm), and all aneurysms were wide-neck. WEB deployment failed in 1 case due to WEB protrusion in a small PICA aneurysm. Additional stent implantation was required for 2 aneurysms to improve intra-aneurysmal WEB positioning. One patient developed a partial posterior cerebral artery territory infarction with transient hemianopsia. Intraoperative rerupture of a ruptured aneurysm could be immediately stopped by WEB deployment due to intrasaccular stasis; however, it might have contributed to a slight disability of the patient. At last angiographic follow-up, 12/15 aneurysms (80%) were completely occluded and 3/15 (20%) had a neck remnant.

CONCLUSIONS

The preliminary results indicate that WEB treatment of proximal PICA aneurysms is feasible with a reasonable safety and efficacy profile. The advantages of intrasaccular flow disruption include preservation of the PICA, durable aneurysm occlusion, and omission of antiplatelet therapy. The low-profile WEB 17 delivery system might enable navigation to distal PICA aneurysms, which needs to be addressed further.

Microsurgical treatment of posterior inferior cerebellar aneurysms based on angioarchitecture supplemented by high-resolution vessel wall MRI: a case series report

BACKGROUND

Surgical treatment of posterior inferior cerebellar artery (PICA) aneurysms is challenging because many are nonsaccular and atherosclerotic. We report our tailored approach to PICA aneurysms, which is based on angioarchitecture supplemented by high-resolution vessel wall MRI (HR-VW MRI) findings.

METHODS

From March 2010 to September 2020, 27 patients with 29 PICA aneurysms underwent surgical treatment in our institution. Since October 2016, HR-VW MRI has been used for aneurysmal wall assessment. Clinical characteristics, radiological data and surgical outcomes were analysed.

RESULTS

Nineteen proximal PICA aneurysms (vertebral artery (VA), P1, P2 and P3) were treated using the far-lateral approach. Ten distal PICA aneurysms (P4, P5) were treated using the suboccipital midline approach. Direct clipping or clip reconstruction was achieved in 19 aneurysms. Ten were trapped in conjunction with extracranial-intracranial or intracranial-intracranial bypass, including three occipital artery-PICA reimplantations, three PICA-VA reimplantations, two PICA-PICA side-to-side anastomoses, one PICA-PICA reimplantation and one PICA-PICA reanastomosis. All aneurysms were eventually completely obliterated and all bypasses remained patent. At the last follow-up, 26 patients (96.2%) achieved a good outcome (modified Rankin Scale score <3). Eight patients underwent HR-VW MRI. Among these, the six aneurysms with focal wall enhancement required bypass and the two with negative enhancement were successfully clipped.

CONCLUSION

PICA aneurysms have a higher frequency of complex features such as large or giant size and fusiform or dissecting morphology. Favourable outcomes were achieved with individualised microsurgical strategies based on angioarchitecture. HR-VW MRI may be used as a promising technique to predict aneurysmal atherosclerosis.

Comparison of Pipeline Embolization Device and Traditional Endovascular Therapeutic Approaches in Distal Cerebral Circulation Aneurysms Using Propensity Score Matching Analysis

Background

Coiling and stent-assisted coiling remain the first-line treatments for distal cerebral circulation aneurysms (DCCAs). The off-label use of the pipeline embolization device (PED) for these aneurysms has been explored recently but remains controversial.

Objective

To compare traditional endovascular therapeutic approaches (coiling and stent-assisted coiling) and PED for DCCAs in a multicenter cohort of patients.

Methods

A multicenter, retrospective cohort comparison study was conducted that included consecutive patients with unruptured DCCAs treated with either traditional endovascular therapeutic approaches or PED placement at three centers between 2016 and 2020. Propensity score matching analysis was applied to adjust for baseline risk factors between the PED and TET groups. Matching was based on age, sex, aneurysm size, location, morphology, adjunctive coiling, treatment history, and preoperative mRS score.

Results

In total, 209 patients with DCCAs treated with PED or traditional endovascular therapeutic approaches were identified. Thirty-seven patients underwent PED treatment, and 172 patients underwent traditional endovascular therapeutic approaches. After propensity score matching, 37 aneurysm pairs were matched, and the baseline characteristics of the patients were balanced between the groups. The complete occlusion rate between PED and traditional endovascular therapeutic approach in both matched cohorts (91.7 vs. 92.3%, p > 0.78) was similar. The rate of periprocedural treatment-related complications in both the PED and traditional endovascular therapeutic groups was 13.5%. Univariate analysis identified average parent vessel diameter as the only predictor of complete occlusion (p = 0.038).

Conclusions

PED is a viable option for treating DCCAs by providing occlusion and complication rates similar to those of traditional endovascular therapeutic approaches. A rigid patient selection procedure and proper planning should be undertaken to reduce treatment-related complications.

Microsurgical treatment of posterior inferior cerebellar aneurysms based on angioarchitecture supplemented by high-resolution vessel wall MRI: a case series report

BACKGROUND

Surgical treatment of posterior inferior cerebellar artery (PICA) aneurysms is challenging because many are nonsaccular and atherosclerotic. We report our tailored approach to PICA aneurysms, which is based on angioarchitecture supplemented by high-resolution vessel wall MRI (HR-VW MRI) findings.

METHODS

From March 2010 to September 2020, 27 patients with 29 PICA aneurysms underwent surgical treatment in our institution. Since October 2016, HR-VW MRI has been used for aneurysmal wall assessment. Clinical characteristics, radiological data and surgical outcomes were analysed.

RESULTS

Nineteen proximal PICA aneurysms (vertebral artery (VA), P1, P2 and P3) were treated using the far-lateral approach. Ten distal PICA aneurysms (P4, P5) were treated using the suboccipital midline approach. Direct clipping or clip reconstruction was achieved in 19 aneurysms. Ten were trapped in conjunction with extracranial-intracranial or intracranial-intracranial bypass, including three occipital artery-PICA reimplantations, three PICA-VA reimplantations, two PICA-PICA side-to-side anastomoses, one PICA-PICA reimplantation and one PICA-PICA reanastomosis. All aneurysms were eventually completely obliterated and all bypasses remained patent. At the last follow-up, 26 patients (96.2%) achieved a good outcome (modified Rankin Scale score <3). Eight patients underwent HR-VW MRI. Among these, the six aneurysms with focal wall enhancement required bypass and the two with negative enhancement were successfully clipped.

CONCLUSION

PICA aneurysms have a higher frequency of complex features such as large or giant size and fusiform or dissecting morphology. Favourable outcomes were achieved with individualised microsurgical strategies based on angioarchitecture. HR-VW MRI may be used as a promising technique to predict aneurysmal atherosclerosis.

Midline suboccipital approach to a vertebral artery–posterior inferior cerebellar artery aneurysm from the rostral end of the patient using ORBEYE

Background:

The midline suboccipital approach with the patient in the prone position is safe and effective for clipping vertebral artery–posterior inferior cerebellar artery (VA–PICA) aneurysms. Using a conventional surgical microscope from the rostral end of the patient for this approach without an extreme head-down position requires the surgeon to overhang the visual axis of the microscope and perform surgical manipulations in an uncomfortable posture. We report performing the midline suboccipital approach from the rostral end with slight head-down position using ORBEYE, a new high-definition (4K) three-dimensional exoscope.

Case Description:

A 65-year-old woman was admitted for clipping of a right unruptured VA–PICA aneurysm (maximum diameter, 5mm) located medially and ventral to the hypoglossal canal. After induction of general anesthesia, the patient was placed in the prone position with the head titled slightly downward. A midline suboccipital approach was performed from the rostral end of the patient using ORBEYE. Clipping was safely accomplished in a comfortable posture. No operative complications occurred. Postoperative computed tomography angiography showed complete aneurysmal obstruction.

Conclusion:

Exoscopic surgery using ORBEYE is feasible for a midline suboccipital approach to VA–PICA aneurysms from the rostral end of the patient with the patient in the prone with slight head-down position.

Bypass Surgery Management of Complex Proximal and Distal Posterior Inferior Cerebellar Artery Aneurysms

BACKGROUND

For the complex posterior inferior cerebellar artery (PICA) aneurysms, standard microsurgical or endovascular technical options were not feasible. To determine the efficacy and outcomes of bypass surgery for complex PICA aneurysms, the authors herein review our recent surgical experience for complex PICA aneurysms.

METHODS

The authors retrospectively reviewed our experience of extracranial-intracranial bypass and intracranial-intracranial bypass surgery in treatment of proximal and distal complex PICA aneurysms at our institution from 2016 to 2020.

RESULTS

Twelve patients harboring 12 complex PICA aneurysms received bypass surgery at our institution. Seven (58.3%) patients with proximal PICA aneurysms underwent extracranial-intracranial bypass. Five (41.7%) patients with distal PICA aneurysms accepted intracranial-intracranial bypass. The postoperative symptom improvement: Of the 6 patients with preoperative hypoperfusion or ischemic of the cerebellar hemisphere, the symptom resolved in 5 patients, improved in 1 patient, of 5 patients with preoperative mass effect, the symptom resolved in 5 patients. During the follow-up period, ten patients had a modified Rankin scale (mRS) score of 0 to 1, and 1 patient had an mRS score of 2. One patient had an mRS score of 3. The long-term graft patency rate was 91.7%. All patients had no recurrence of intracranial aneurysm.

CONCLUSIONS

Base on the complexity of anatomy structure and the vascular architecture, an individualized strategy was proposed for each patient. The use of different types of bypass procedures (occipital artery-PICA end-to-end bypass, PICA-PICA end-to-end anastomosis, and/or occipital artery graft) can safely and effectively manage these complex PICA aneurysms.

A Case Report on the Progressive Hunterian Ligation of an Intracranial Aneurysm by Flow Diversion: The Endovascular Selverstone Clamp

Proximal Hunterian ligation remains a treatment option for select complex brain aneurysms. Progressive occlusion over time (as accomplished with Selverstone clamping) can enable collateral flow to develop while the aneurysm regresses or occludes.

A 50-year-old woman presented with an unruptured 16-mm posterior inferior cerebellar artery (PICA) aneurysm. The aneurysm was located 4 mm distal to the PICA origin. It was bilobed, incorporating the PICA. The PICA inflow and outflow zone orientation prevented direct stent reconstruction. Surgical clipping with bypass was considered. Alternatively, an attempt at proximal ligation of the PICA via flow-diverting stents was offered. After extensive counseling, the patient decided to proceed with endovascular treatment.

Two overlapping pipeline embolization devices (PED) were placed into the vertebral artery, covering the PICA origin. The one-year follow-up angiography demonstrated flow reduction within the aneurysm and the distal PICA. A de novo (previously not opacified) accessory PICA collateral had developed, partially taking over the arterial supply of the PICA territory. The newly established accessory PICA originated from the vertebral artery 8 mm distal to the PICA origin. After two years, the aneurysm was fully obliterated, and the true PICA was occluded and functionally replaced by the accessory PICA.

The current case suggests that progressive Hunterian ligation via endovascular flow diversion can be an effective treatment strategy for true PICA aneurysms. However, this strategy should only be considered if no immediate aneurysm occlusion is required or if all alternative methods are associated with substantial risk.

Peptidomic profiling of cerebrospinal fluid from patients with intracranial saccular aneurysms

Intracranial saccular aneurysms (ISA) represent 90%-95% of all intracranial aneurysm cases, characterizing abnormal pockets at arterial branch points. Ruptures lead to subarachnoid hemorrhages (SAH) and poor prognoses. We applied mass spectrometry-based peptidomics to investigate the peptidome of twelve cerebrospinal fluid (CSF) samples collected from eleven patients diagnosed with ISA. For peptide profile analyses, participants were classified into: 1) ruptured intracranial saccular aneurysms (RIA), 2) unruptured intracranial saccular aneurysms (UIA), and late-ruptured intracranial saccular aneurysms (LRIA). Altogether, a total of 2199 peptides were detected by both Mascot and Peaks software, from which 484 (22.0%) were unique peptides. All unique peptides presented conserved chains, domains, regions of protein modulation and/or post-translational modification sites related to human diseases. Gene Ontology (GO) analyses of peptide precursor proteins showed that 42% are involved in binding, 56% in cellular anatomical entities, and 39% in intercellular signaling molecules. Unique peptides identified in patients diagnosed with RIA have a larger molecular weight and a distinctive developmental process compared to UIA and LRIA (P ≤ 0.05). Continued investigations will allow the characterization of the biological and clinical significance of the peptides identified in the present study, as well as identify prototypes for peptide-based pharmacological therapies to treat ISA. SIGNIFICANCE.

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.

Functional Outcomes After Treatment of Posterior Inferior Cerebellar Artery Aneurysms

Objective Aneurysms of the posterior inferior cerebellar artery (PICA) are a rare cause of subarachnoid hemorrhage. Treatment for this type of aneurysm may be microsurgical clipping or endovascular. This decision is based on patient characteristics, aneurysm location and dimensions, along with surgeon and institutional experience. In this study we aim to assess the outcomes of surgical and endovascular treatment of PICA aneurysms. Methods We retrospectively reviewed the charts of 52 patients who were admitted to Vancouver General Hospital for ruptured or symptomatic PICA aneurysms between 2005 and 2015. Modified Rankin scores were assigned at the time of discharge and at two subsequent follow-up time points. The mean short-term follow-up period post-operatively was 11.1 months and the mean long-term follow-up period was 19.3 months. Clinical and radiological characteristics were collected for all patients. Results Of the 52 patients, two died prior to obtaining treatment. Of the 50 patients who were treated for their PICA aneurysm, 39 presented with subarachnoid hemorrhage while 11 had symptomatic unruptured PICA aneurysms. Overall, 11 patients had endovascular treatment (coil embolization) while 39 patients underwent microsurgical clipping/trapping of the aneurysm. At the time of hospital discharge, patients in the microsurgical group trended towards a better the modified Rankin Scale score (2.3) compared to the endovascular group, though this did not reach significance (3.0) (p=0.20). The long-term score in the endovascular group (1.6) was also comparable to the microsurgical group (1.9) (p=0.55). Conclusion While the early outcomes in patients treated endovascularly appear better, there is no statistically significant difference in outcomes between the microsurgical and endovascular treatment groups at short- and long-term follow-up.

Endovascular sacrifice of the proximal posterior inferior cerebellar artery for treatment of ruptured intracranial aneurysms

BACKGROUND

Ruptured aneurysms of the intracranial vertebral artery (VA) or posterior inferior cerebellar artery (PICA) are challenging to treat as they are often dissecting aneurysms necessitating direct sacrifice of the diseased segment, which is thought to carry high morbidity due to brainstem and cerebellar stroke. However, relatively few studies evaluating outcomes following VA or proximal PICA sacrifice exist. We sought to determine the efficacy and outcomes of endovascular VA/PICA sacrifice.

METHODS

A retrospective series of ruptured VA/PICA aneurysms treated by endovascular sacrifice of the VA (including the PICA origin) or proximal PICA is reviewed. Collected data included demographic, radiologic, clinical, and disability information.

RESULTS

Twenty-one patients were identified. Median age was 57 years (IQR 11); 15 were female. The Hunt and Hess grade was mostly 3 and 4 (18/21). Seven cases (33%) involved VA-V4 at the PICA take-off, and 14 cases (67%) involved the PICA exclusively. For VA pathology, V4 was sacrificed in all cases, while for PICA pathology, sacrificed segments included anterior medullary (4/14), lateral medullary (7/14), and tonsillomedullary (3/14) segments. Four patients went to hospice (19%). Twelve patients (57%) had evidence of stroke on follow-up imaging: cerebellar (8), medullary (1), and both (3). One patient required suboccipital decompression for brainstem compression. No aneurysm re-rupture occurred. Median discharge modified Rankin Scale score was 2.0 (IQR 2), which decreased to 1.0 (IQR 1) at median follow-up of 6.5 months (IQR 23).

CONCLUSIONS

Endovascular sacrifice of V4 or PICA aneurysms may carry less morbidity than previously thought, and is a viable alternative for poor surgical candidates or those with good collateral perfusion.

Coiling for a saccular aneurysm on the caudal channel in double origin of the posterior inferior cerebellar artery

BACKGROUND

Double origin of the posterior inferior cerebellar artery (DOPICA) is a rare cranial imaging finding with an incidence of 0.36-6% reported in various retrospective studies. Aneurysms on a DOPICA are even rarer.

CASE DESCRIPTION

A 34-year-old women hospitalised for subarachnoid haemorrhage showed a ruptured aneurysm arising from the caudal channel of the DOPICA. Endovascular treatment was selected, and the aneurysm was successfully and completely embolised using two coils.

CONCLUSIONS

To date, a total of three previous saccular aneurysms of the DOPICA itself have been reported, all of which were treated using endovascular methods. Our case is the first report of a ruptured saccular aneurysm arising from the non-branching segment of the caudal channel of the DOPICA.

Vertebral artery and posterior inferior cerebellar artery aneurysms: Results of microsurgical treatment of eighty patients

Background

The choice of surgical approaches and options for the microsurgical vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms repair remains controversial.

Methods

A retrospective analysis of the clinical, surgical, and angiographic data of 80 patients with VA and PICA aneurysms treated from 2012 to 2018 was performed.

Results

The aneurysms were saccular in 50 cases (62.5%) and fusiform in 30 cases (37.5%). The median suboccipital craniotomy was the most common approach (73.8%). Retrosigmoid craniotomy was performed in 25% of patients. There were the following types of microsurgical operations: neck clipping (61.25%), clipping with the artery lumen formation (13.75%), trapping (10%), proximal clipping (5%), and deconstruction with anastomosis (10%). Fifty-seven (71.3%) patients were discharged without worsening of the clinical signs after surgery. The most common postoperative neurological disorder was palsy of IX and X cranial nerve revealed in 14 (17.5%) patients. No fatal outcomes or patients in vegetative state were identified. The complete occlusion of PICA and VA aneurysms according angiography was in 77 (96.3%) cases.

Conclusion

Microsurgical treatment is an effective method for VA and PICA aneurysms. The majority of VA and PICA aneurysms do not require complex basal approaches. A thorough preoperative planning, reconstructive clipping techniques, and anastomoses creation, as well as patient selection based on the established algorithms and consultations with endovascular surgeons, may reduce the number of complications and increase the rate of complete microsurgical occlusion in VA and PICA aneurysms.

[Microsurgical treatment of aneurysms of vertebral and posterior-lower cerebellar arteries: surgical approaches, exclusion options, treatment results]

Aneurysms of vertebral (VA) and posterior inferior cerebellar arteries (PICA) are relatively rare pathologies and account for 3.4% of the total number of intracranial aneurysms.

MATERIAL AND METHODS

The experience of microsurgical treatment of 67 patients with VA and PICA aneurysms in N.N. Burdenko National Medical Research Center for Neurosurgery of the RF Ministry of Health from 2012 to 2017 is presented.

RESULTS

Most patients underwent reconstructive microsurgical interventions: clipping of the aneurysm neck in 42 (62.7%) patients and complex clipping with the formation of arterial opening - in 10 (14.9%). Exclusion of the aneurysm together with the carrier artery (trapping, proximal clipping) was performed on 10 (14.9%) patients. In 5 (7.5%) patients, deconstruction of the carrier artery of the aneurysm was performed after creating local anastomoses. The radical exclusion of aneurysms in the studied group was 95.5%. Postoperative dysfunction of the caudal group of cranial nerves was detected in 11 (16.4%) patients. There were no lethal outcomes, or cases with vegetative status outcomes.

CONCLUSION

Microsurgical intervention is an effective way to treat VA and PICA aneurysms, subject to the principles of patient selection based on existing treatment algorithms as well as adherence to an interdisciplinary approach.

Ruptured PICA aneurysms: presentation and treatment outcomes compared to other posterior circulation aneurysms. A Swiss SOS study

BACKGROUND AND PURPOSE

Aneurysms of the posterior inferior cerebellar artery (PICA) are relatively uncommon and evidence is sparse about patients presenting with ruptured PICA aneurysms. We performed an analysis of the Swiss SOS national registry to describe clinical presentation, treatment pattern, and neurological outcome of patients with ruptured PICA aneurysms compared with other ruptured posterior circulation (PC) aneurysms.

METHODS

This was a retrospective analysis of anonymized data from the Swiss SOS registry (Swiss Study on Aneurysmal Subarachnoid Hemorrhage; 2009-2014). Patients with ruptured PC aneurysms were subdivided into a PICA and non-PICA group. Clinical, radiological, and treatment-related variables were identified, and their impact on the neurological outcome was determined in terms of modified Rankin score at discharge and at 1 year of follow-up for the two groups.

RESULTS

Data from 1864 aneurysmal subarachnoid hemorrhage patients were reviewed. There were 264 patients with a ruptured PC aneurysm. Seventy-four PICA aneurysms represented 28% of the series; clinical and radiological characteristics at admission were comparable between the PICA and non-PICA group. Surgical treatment was accomplished in 28% of patients in the PICA group and in the 4.8% of patients in the non-PICA group. No statistically significant difference was found between the two groups in terms of complications after treatment. Hydrocephalus requiring definitive shunt was needed in 21.6% of PICA patients (p = 0.6); cranial nerve deficit was present in average a quarter of the patients in both PICA and non-PICA group with no statistical difference (p = 0.3). A more favorable outcome (66.2%) was reported in the PICA group at discharge (p < 0.05) but this difference faded over time with a similar neurological outcome at 1-year follow-up (p = 0.09) between both PICA and non-PICA group. The Kaplan-Meyer estimation showed no significant difference in the mortality rate between both groups (p = 0.08).

CONCLUSIONS

In the present study, patients with ruptured PICA aneurysms had a favorable neurological outcome in more than two thirds of cases, similar to patients with other ruptured PC aneurysms. Surgical treatment remains a valid option in a third of cases with ruptured PICA aneurysms.

Distal posterior inferior cerebellar artery aneurysm with cerebellar arteriovenous malformation treated by open surgery: a case report

Background

The detection of a feeder aneurysm and an arteriovenous malformation (AVM) is relatively rare for the intracranial AVM. The distal posterior inferior cerebellar artery aneurysm (DPICAAn) is reported to coexist or relate with the cerebellar AVM. In previous reports about the treatment of a DPICAAn and a cerebellar AVM, endovascular embolization with the sacrifice of the posterior inferior cerebellar artery (PICA) has often been selected. However, there have been few reports of simultaneous open surgery for coexistent cases of DPICAAn and cerebellar AVM.

Case description

A 67-year-old male presented with a headache. We detected a right DPICAAn in the telovelotonsillar segment and a cerebellar AVM primarily fed by the left superior cerebellar artery (SCA). In addition, the nidus was located medially in the left upper cerebellar hemisphere. Magnetic resonance imaging raised suspicions of asymptomatic past hemorrhage in the cerebellar AVM. The left PICA was agenesis, and the right PICA perfused the bilateral inferior cerebellar hemispheres; thus, the right PICA could not be sacrificed. We selected open surgery to prevent any hemorrhagic event from the DPICAAn and the cerebellar AVM. The cerebellar AVM was completely removed, and the DPICAAn was successfully clipped in a single-session open surgery.

Conclusions

Open surgery can be considered for DPICAAn and cerebellar AVM. The anatomical location of the DPICAAn and AVM contributed to the success of a single-session open surgery.

Dissecting distal cerebellar artery aneurysms: options beyond a parent vessel sacrifice

Parent vessel occlusion (PVO) is the conventional endovascular treatment (EVT) for dissecting distal cerebellar artery aneurysms (DCAA). The associated ischemic sequelae are often well-tolerated. However, at the outset, the magnitude of this risk is uncertain. Meanwhile, non-PVO endovascular treatments (EVT) are deemed to provide incomplete protection from a rebleed. This study reviews our experience in the management of dissecting DCAA with emphasis on the effectiveness of parent vessel-preserving endovascular strategies as compared to PVO. Our institutional database was reviewed for all the dissecting DCAA aneurysms treated by endovascular means between Nov 2015 and Oct 2018. Their clinical presentations, imaging findings, EVT techniques, and clinical outcomes were retrospectively evaluated. Eighteen dissecting DCAA were identified: 13 in the posterior-inferior cerebellar artery (PICA), 3 in anterior-inferior cerebellar artery (AICA), and 2 in superior cerebellar artery (SCA). Median patient age was 61 years (range 40-86; average 60.7 years) with a 5:1 female predominance. Nine (6 in the PICA and 3 in the AICA) patients were managed by parent vessel-preserving strategies (6 with isolated endosaccular coiling and 3 with telescoping stents) while the remaining 9 (7 in the PICA and 2 in the SCA) were treated by PVO.The frequency of early rebleed was the same (11%) in both the treatment arms. One patient from the PVO arm suffered an extensive cerebellar infarct that mandated decompressive craniectomy and adversely affected her recovery. There were no such complications in patients treated with parent vessel-preserving strategies. No recurrence/rebleed was encountered in the 3 aneurysms secured using telescoping stents. Overall, excellent clinical outcomes (mRS of 0 and 1) were sparsely seen in the patients who had PVO (89 vs 23%). In dissecting DCAA, aforedescribed, parent vessel-preserving strategies are as effective as the more frequently used option of PVO in preventing an early rebleed. However, these are technically challenging, may be feasible in a smaller proportion of patients, and would need meticulous imaging follow-up in the acute period. When successfully implemented, these strategies can deliver excellent clinical outcomes and eliminate the uncertain risk of ischemic complications associated with PVO.

Surgical treatment of a posterior inferior cerebellar artery aneurysm via transcranial neuroendoscopic approach: A case report

RATIONALE

Posterior inferior cerebellar artery (PICA) aneurysms are rare and heterogeneous in both location and morphology, and the management of proximal PICA aneurysms is challenging. In 2011, Joaquim reported a successfully treated VA-PICA ruptured aneurysm using a pure endoscopic endonasal transclival approach for the first time. However, the patient suffered CSF rhinorrhea and underwent an additional operation to repair the CSF leak. In this case report, we describe the treatment of proximal PICA aneurysm by transcranial neuroendoscopic approach.

PATIENT CONCERNS

A 68-year-old woman presented with a sudden onset of severe headache followed by loss of consciousness and computed tomography of the head showed a mild SAH, located predominantly in the posterior fossa. Clinical signs and symptoms included headache and a positive meningeal irritation sign; no other neurological symptoms were found.

DIAGNOSIS

A 3-dimensional CT angiography revealed the diagnosis as left VA-PICA junction aneurysm.

INTERVENTIONS

After a medical treatment, the patient regained consciousness and the aneurysm was treated by pure neuroendoscopy via a modified far-lateral surgical approach.

OUTCOMES

The patient recovered well after the procedure, and the post-operation image view shows a proper placement of the clip, obliteration of the aneurysm, and the parental artery was unobstructed.

LESSONS

To our best knowledge, this is the first reported case of treating aneurysm by neuroendoscopic transcranial approach and the second reported case treated by endoscopy. In the present report, we propose that ruptured VA-PICA junction aneurysms could be treated by a pure transcranial neuroendoscopic approach. The advantages of this approach included no risk of CSF rhinorrhea compared with the endoscopic endonasal transclival approach.

Clinical importance of the posterior meningeal artery: a review of the literature

The posterior meningeal artery, which arises from the vertebral artery, is a critical artery in neurological lesions. However, a comprehensive review of the importance of the posterior meningeal artery is currently lacking. In this study, we used the PubMed database to perform a review of the literature on the posterior meningeal artery to increase our understanding of its role in vascular lesions. The posterior meningeal artery provides the main blood supply to the paramedial and medial portions of the dura covering the cerebellar convexity. The posterior meningeal artery is often involved in dural arteriovenous fistulas occurring near the posterior fossa, and the posterior meningeal artery can be the path for transarterial embolisation or a path through which to monitor the degree of dural arteriovenous fistula embolisation. In posterior circulation ischaemia and moyamoya disease, the posterior meningeal artery can form transdural anastomoses with pial arteries at the surface of the brain, and these can help prevent ischemia. The posterior meningeal artery can also develop aneurysms, most of which are traumatic pseudoaneurysms; patients should therefore be treated in a timely manner or followed up carefully in cases of rebleeding. In addition, during a craniotomy, the posterior meningeal artery should be protected intraoperatively to avoid damaging any transdural anastomosis that may be present. In addition, when the posterior meningeal artery is the main feeding artery of an intracranial tumour, that artery is a satisfactory path for preoperative embolisation. Briefly, the posterior meningeal artery is a very important artery in neurosurgery.

A2, M2, P2 aneurysms and beyond: results of treatment with pipeline embolization device in 65 patients

BACKGROUND

Intracranial aneurysms located in the distal vessels are rare and remain a challenge to treat through surgical or endovascular interventions.

OBJECTIVE

To describe a multicenter approach with flow diversion using the pipeline embolization device (PED) for treatment of distal intracranial aneurysms.

METHODS

Cases of distal intracranial aneurysms defined as starting on or beyond the A2 anterior cerebral artery, M2 middle cerebral artery, and P2 posterior cerebral artery segments were included in the final analysis.

RESULTS

65 patients with distal aneurysms treated with the PED were analyzed. Median aneurysm size at the largest diameter was 7.0 mm, 60% were of a saccular morphology, and 9/65 (13.8%) patients presented in the setting of acute rupture. Angiographic follow-up data were available for 53 patients, with a median follow-up time of 6 months: 44/53 (83%) aneurysms showed complete obliteration, 7/53 (13.2%) showed reduced filling, and 2/53 (3%) showed persistent filling. There was no association between patient characteristics, including aneurysm size (P=0.36), parent vessel diameter (P=0.27), location (P=0.81), morphology (P=0.63), ruptured status on admission (P=0.57), or evidence of angiographic occlusion at the end of the embolization procedure (P=0.49). Clinical outcome data were available for 60/65 patients: 95% (57/60) had good clinical outcome (modified Rankin Scale score of 0-2) at 3 months.

CONCLUSIONS

This large multicenter study of patients with A2, M2, and P2 distal aneurysms treated with the PED showed that flow diversion may be an effective treatment approach for this rare type of vascular pathology. The procedural compilation rate of 7.7% indicates the need for further studies as the flow diversion technology constantly evolves.

Endovascular management of ruptured distal posterior inferior cerebellar artery aneurysms: A retrospective cohort study

Distal posterior inferior cerebellar artery (PICA) aneurysm is a kind of rare intracranial aneurysm with controversial evidence in managements. The main purposes of this research are to study the safety and effectiveness of parent artery occlusion (PAO) compared with selective aneurysm coiling (SAC) as well as figure out factors that affect the outcomes.All characteristics of patients that diagnosed with ruptured distal PICA aneurysm and treated with endovascular management in our hospital from July 2009 to February 2016 were retrospectively collected. Details include complete occlusion rate, procedure-related complications and Modified Rankin Scale (mRS) of 31 months (mean) follow-up.Total 36 patients finally met the criterions and were included in the present study. New imaging infarction was observed in 12 (33.33%) patients. And 10 of them showed no apparent neurological dysfunctions after 34 months (mean) follow-up; 1 remained coma status since the symptom onset; and 1 patient died. 27 (75%) patients got a mRS ≤ 2 at the discharge while 20 (86.96%) patients with 3-year follow-up after the operation. There is no significant difference between patients treated with SAC and PAO in both complications and functional recovery in 3-years follow-up period. Hunt&Hess classification (H&H), age, and hydrocephalus are risk factors for functional recovery at discharge.PAO is safe and efficient in the management of distal PICA aneurysms while complications and outcomes are similar with SAC. H&H, age, and hydrocephalus are predicting factors for the mRS at discharge. Further prospective study is still needed to confirm the results of present study.

Microsurgical Clipping of Ruptured Distal Posterior Inferior Cerebellar Artery Aneurysm: 3-Dimensional Operative Video

The distal posterior inferior cerebellar artery (PICA) is a rare site of aneurysm formation. Only small case series and case reports regarding surgical treatment are found in the literature.The PICA is divided into 5 segments (anterior medullary, lateral medullary, tonsilomedullary, telovelotonsillary, and cortical), and the distal ones represent the most complex, due to anatomic variations. We present a case of a 69-yr-old female patient who has suffered from a sudden and intense occipital headache, associated with nausea and vomiting. CT scan showed intraventricular hemorrhage, and further investigation with MRI and MR Angiography revealed a small distal PICA aneurysm, at the superior part of the medial aspect of the left cerebellar tonsil. Digital angiography has demonstrated the aneurysm at the tonsilomedullary segment of the PICA. In this 3-dimensional video, the authors show the microsurgical clipping of a saccular distal PICA aneurysm in the close relation to a choroidal branch, performed by median suboccipital craniotomy. Step-by-step of the dissection, relevant surrounding anatomy and aneurysm clipping is demonstrated. The patient signed the Institutional Consent Form, which allows the use of his/her images and videos for any type of medical publications in conferences and/or scientific articles.

The use of flow diverters to treat aneurysms of the posterior inferior cerebellar artery: Report of three cases

Objective The objective of this study was to report our experience on the use of flow diverting stents placed within the posterior inferior cerebellar artery (PICA) as a treatment option for aneurysms of the PICA. Methods Three patients with aneurysms of the PICA, both ruptured and unruptured, underwent treatment of their aneurysms with placement of a single flow diverter in the PICA across the neck of the aneurysm. Adjunctive techniques such as coiling were not used. We present the angiographic and clinical follow-up data. Results The procedure was a technical success in all cases and there were no intraoperative complications. Follow-up data were available for two patients and this showed complete occlusion of the aneurysm with the PICA remaining patent. There was no evidence, either clinical or radiological, of medullary or pontine infarction. One patient died during the follow-up period from an unrelated medical illness (community acquired pneumonia). Conclusion Flow diverters can be successfully placed within the PICA to treat both ruptured and unruptured aneurysms, and they represent an alternative treatment option to endovascular coiling or microscopic neurosurgery.

Decision Making in Surgery for Nonsaccular Posterior Inferior Cerebellar Artery Aneurysms With Special Reference to Intraoperative Assessment of Collateral Blood Flow and Neurophysiological Function

BACKGROUND

Posterior inferior cerebellar artery (PICA) aneurysms represent a challenging pathology. PICA sacrifice is often necessary, due to the high proportion of nonsaccular aneurysms that can be found in this location. Several treatments are available, but the infrequency of these aneurysms and the increasing number of endovascular techniques have limited the development of a standardized algorithm for cases in which open surgery is indicated.

OBJECTIVE

We present our series of nonsaccular PICA aneurysms, in the attempt to define an algorithm for their surgical management.

METHODS

We retrospectively reviewed the operation database, identifying patients harboring nonsaccular PICA aneurysms who were surgically treated at our institution from 2007 to 2016.

RESULTS

During a 9-yr period, 17 patients harboring 18 nonsaccular PICA aneurysms were surgically treated at our institution. Fourteen (7.7%) aneurysms were located within the proximal PICA (including those located at the vertebral artery-PICA junction), and 4 were located distally. We performed PICA revascularization in 8 (57.1%) cases of proximal aneurysms (n = 4, PICA-PICA bypass; n = 4, occipital artery-PICA bypass). We based our decision whether to perform bypass on intraoperative test occlusion with indocyanine green (ICG) videoangiography and neurophysiological monitoring. In no cases, bypass was necessary for distal aneurysms.

CONCLUSION

For nonsaccular PICA aneurysms, in which vessel occlusion is often necessary, it is possible to adopt a selective use of revascularization techniques. Intraoperative occlusion test with ICG videoangiography and neurophysiological monitoring provides reliable indications, allowing real-time assessment of collateral circulation.

Efficacy and Outcomes of Posterior Inferior Cerebellar Artery (PICA) Bypass for Proximal PICA and Vertebral Artery-PICA Aneurysms: A Case Series

BACKGROUND

Nonsaccular vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms have high morbidity and mortality rates and are difficult to treat using standard microsurgical or endovascular techniques. Definitive revascularization can require clip trapping and/or vessel sacrifice, with PICA bypass. The published surgical experience with these approaches is limited. We herein review our recent surgical experience with PICA revascularization for complex PICA and VA/PICA aneurysms.

OBJECTIVE

To determine the efficacy and outcomes of PICA bypass for revascularization of nonsaccular PICA and VA/PICA aneurysms.

METHODS

Retrospective analysis of an institutional review board-approved, prospective database was performed to identify patients with PICA and VA/PICA aneurysms treated with PICA bypass at a single institution. Demographic information, aneurysm characteristics, temporary clip time, and neurological outcomes were recorded.

RESULTS

Ten cases of PICA revascularization were performed for both ruptured (n = 8) and unruptured (n = 2) nonsaccular proximal PICA or VA/PICA aneurysms. Seven cases were performed without vessel grafts; 3 cases required harvest of the descending branch of the lateral femoral circumflex artery. Mean temporary clip time was 38 min (range 27-50 min). Good outcomes (Glasgow Outcomes Scale score of 5) were achieved in 70% (n = 7) of patients at time of discharge; the remaining patients had a Glasgow Outcomes Scale of 3. Two bypass-related complications occurred in this series; a hematoma at the graft harvest site requiring evacuation, and severe bypass graft spasm requiring multiple endovascular treatments.

CONCLUSION

PICA bypass can be a safe, effective, and highly customizable tool for the revascularization of patients with nonsaccular proximal PICA and VA/PICA aneurysms.

Flow diversion for the treatment of posterior inferior cerebellar artery aneurysms: a novel classification and strategies

Background

The pipeline embolization device (PED) is frequently used in the treatment of anterior circulation aneurysms, especially around the carotid siphon, with generally excellent results. However, treatment of posterior inferior cerebellar artery (PICA) aneurysms with flow diversion (FD) has not been specifically described or discussed. While there are reports of treating PICA aneurysms using placement of FD stents in the vertebral artery, there are no reports of treating these lesions by placement of flow diverting stents in the PICA vessel itself. Due to the unique anatomy and morphology of these aneurysms, it requires special attention. We assessed our multi-institutional experience treating these lesions, including the first reported cases of the PED placed within the PICA.

Methods

Institutional databases of neuroendovascular procedures were reviewed for cases of intracranial aneurysms treated with the PED. Patient and aneurysm data as well as angiographic imaging were reviewed for all cases of PICA aneurysms treated with the PED. PICA aneurysms were defined as aneurysms that involved the PICA. Vertebral aneurysms without disease in the PICA were excluded from the study.

Results

10 PICA aneurysms were treated during the study period. These were classified based on their morphology and location into two main types and five total subtypes for consideration of treatment with flow diversion. All aneurysms were successfully treated, with 8/10 completely obliterated and 2 with a partial reduction in size. Three patients had the PED placed entirely in the PICA and no patient suffered from a medullary or cerebellar stroke. All PEDs were patent and all patients were independent at the last follow-up.

Conclusions

The PED may be used successfully to treat select aneurysms of the PICA. We present the first described cases of successful PED treatment of PICA aneurysms with direct placement of the PED in the PICA vessel itself. The proposed classification system aids in that selection.

Simple Lateral Suboccipital Approach and Modification for Vertebral Artery Aneurysms: A Study of 52 Cases Over 10 Years

INTRODUCTION

Complex skull base approaches are frequently used to treat intracranial vertebral artery (VA) and proximal posterior inferior cerebellar artery (PICA) aneurysms. These complex procedures are associated with higher risk of neurovascular injury. Hence, a less-invasive surgical approach is needed to improve the efficacy and safety of treatment.

METHODS

A retrospective analysis was conducted on clinical and radiologic data from surgeries in which simple lateral suboccipital and "lateral-enough" approaches were used to clip VA aneurysms in the Department of Neurosurgery at Helsinki University Central Hospital from 2000 to 2009.

RESULTS

Fifty-two VA or PICA aneurysms were treated using the simple lateral suboccipital approach. Sixteen patients (31%) presented with an unruptured aneurysm, 21 patients (40%) with World Federation of Neurosurgical Societies (WFNS) grade 1-3, and 15 patients (29%) with World Federation of Neurosurgical Societies grade 4-5. The aneurysms were saccular in 48 cases (92%), dissecting in 3 cases (6%), and fusiform in 1 case (2%). The most common aneurysm location was the VA-PICA junction (81%). The mean final modified Rankin Scale score was 2, and in unruptured cases, all patients had favorable clinical outcomes. The main causes of unfavorable outcome were poor preoperative clinical grade (P = 0.002), preoperative intraventricular hemorrhage (P = 0.008), postoperative hydrocephalus (P = 0.003), brain infarction (P = 0.005), and postoperative pneumonia (P < 0.001).

CONCLUSIONS

We describe a 10-year experience using a simple lateral suboccipital approach and its modification by the senior author (J.H.) to treat VA and proximal PICA aneurysms. Unfavorable outcome was related to the poor preoperative clinical grade, preoperative intraventricular hemorrhage, and postoperative pneumonia.

A case with coil embolization for ruptured aneurysm associated with fenestration of the posterior inferior cerebellar artery

An 87-year-old man hospitalized for subarachnoid hemorrhage showed a ruptured aneurysm arising from fenestration of the posterior inferior cerebellar artery. Endovascular treatment was selected and the aneurysm and superior limb were embolized completely using three coils. Fenestration of the posterior cerebellar artery is exceedingly rare. In addition, we present a first case of aneurysm as fenestration of the posterior inferior cerebellar artery that was definitively identified as a cause of bleeding.

Treatment strategies of ruptured posterior inferior cerebellar artery aneurysm according to its segment

Background:

The aim of this study was to evaluate the clinical outcomes between endovascular treatment (EVT) and surgery of the ruptured posterior inferior cerebellar artery (PICA) aneurysms and suggest proper management strategies according to the PICA segment.

Methods:

We retrospectively analyzed clinical and radiological data of patients with ruptured PICA aneurysms who underwent surgery or EVT from three different institutes. Clinical outcomes were evaluated by mRS.

Results:

We collected 39 consecutive patients with 39 ruptured PICA aneurysms; 26 patients were with proximal segment aneurysm and 13 patients were with distal. Of the 26 proximal PICA aneurysms, 20 aneurysms were treated with EVT and 6 aneurysms were treated with surgery. EVT seemed to have more favorable clinical outcome (mRS 0–2; mean mRS, 1.75 for EVT vs 3.50 for surgery, P = 0.152). Of the 13 distal PICA aneurysms, 7 aneurysms were treated with EVT and 6 were treated with surgery. Surgery showed more favorable clinical outcome (mean mRS, 2.63 for EVT vs 0.33 for surgery, P = 0.023) and lower procedure-related complication rate (42.9% for EVT vs 0% for surgery, P = 0.046) than EVT.

Conclusions:

For the treatment of ruptured PICA aneurysms, EVT seemed to have more favorable outcomes for proximal segment, while surgery showed more favorable outcomes for distal segment. Additional experience and follow-up are needed in a larger series to state the efficacy of this strategy.

Far-Lateral Approach Without Drilling the Occipital Condyle for Vertebral Artery–Posterior Inferior Cerebellar Artery Aneurysms

BACKGROUND: The far-lateral transcondylar surgical approach is often used to clip vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms. The role of condyle resection during this approach is controversial.

OBJECTIVE: To evaluate patient outcomes in patients with VA–PICA aneurysms in whom drilling the occipital condyle was not necessary.

METHODS: Between May 2005 and December 2012, a total of 56 consecutive patients with incidental or ruptured VA–PICA aneurysms underwent surgery with a far-lateral approach without condylar resection. Clinical presentation, surgical reports, presurgery and postsurgery radiological examinations, and clinical follow-up reports were assessed. Anatomic aneurysm location was analyzed through angiography or computed tomography angiography. We compared postsurgical Glasgow Outcome Scale scores, modified Rankin Scale scores, and morbidity in 2 groups: those with aneurysms in the anterior medullary segment and those with aneurysms in the lateral medullary segment.

RESULTS: The predominant presentation was subarachnoid hemorrhage in 34 patients (60.7%). Most aneurysms (n = 27 [48.2%]) were located in the lateral medullary segment of the PICA, followed by the anterior medullary segment (n = 25 [44.6%]). Total aneurysm occlusion was achieved in 100% of patients, and bypass techniques were necessary in 3 patients (5.4%). Fifty-two patients (92.8%) had Glasgow Outcome Scale scores of 4 or 5 postsurgery.

CONCLUSIONS: A far-lateral approach that leaves the occipital condyle intact is adequate for treating most patients with VA–PICA aneurysms.

Current Treatment Strategies for Intracranial Aneurysms: An Overview

Intracranial aneurysm is a leading cause of stroke. Its treatment has evolved over the past 2 decades. This review summarizes the treatment strategies for intracranial aneurysms from 3 different perspectives: open surgery approach, transluminal treatment approach, and new technologies being used or trialed. We introduce most of the available treatment techniques in detail, including contralateral clipping, wrapping and clipping, double catheters assisting coiling and waffle-cone technique, and so on. Data from major trials such as Analysis of Treatment by Endovascular approach of Non-ruptured Aneurysms (ATENA), Internal Subarachnoid Trial (ISAT), Clinical and Anatomical Results in the Treatment of Ruptured Intracranial Aneurysms (CLARITY), and Barrow Ruptured Aneurysm Trial (BRAT) as well as information from other clinical reports and local experience are reviewed to suggest a clinical pathway for treating different types of intracranial aneurysms. It will be a valuable supplement to the current existing guidelines. We hope it could help assisting real-time decision-making in clinical practices and also encourage advancements in managing the disease.

Management of posterior inferior cerebellar artery aneurysms: What factors play the most important role in outcome?

BACKGROUND

Posterior inferior cerebellar artery (PICA) aneurysms are an uncommon, heterogeneous group of aneurysms with poorer clinical outcomes compared to other intracranial aneurysms. We performed a multicenter retrospective study to analyze the outcome in a large series of patients treated with modern microsurgical and endovascular techniques.

METHODS

Records of 94 patients treated for PICA aneurysms between 2000 and 2015 at three large tertiary referral centers were retrospectively reviewed.

RESULTS

Eighty-three patients met inclusion criteria and of these, two died before treatment, leaving 81 treated patients (43 underwent endovascular and 38 surgical treatment). Among patients treated endovascularly, procedure-related complications occurred in four cases (11.8%). Six patients (19.4%) suffered from complications directly associated with surgery. Recurrences occurred in 0% of surgical and in 16.3% of endovascularly treated patients, requiring treatment. Patients with unruptured asymptomatic aneurysms had good outcomes. In the group of 67 ruptured aneurysms, 16 endovascularly (47.1%) and 15 surgically (48.4%) treated patients had modified Rankin scale (mRS) scores of 3-6. Of patients in poor neurological condition (Hunt & Hess (H&H) IV-V at admission), 84.6% suffered a poor clinical outcome. Fifty percent of patients with distal and 31.9% patients with proximal ruptured PICA aneurysms suffered a poor neurological outcome.

CONCLUSIONS

This study of PICA aneurysms demonstrates that results of both treatment modalities are comparable. However, endovascular treatment is associated with higher risks of recurrence, requiring additional treatment. Outcomes were mostly impacted by clinical state at admission.

Safety and efficacy of treatment strategies for posterior inferior cerebellar artery aneurysms: a systematic review and meta-analysis

INTRODUCTION

We conducted a systematic review of the literature to evaluate the safety and efficacy of treatment strategies for PICA aneurysms.

METHODS

A systematic search of Medline, EMBASE, Scopus, and Web of Science was done for studies published through November 2015. We included studies that described treatment of PICA aneurysms with ≥10 patients. Random-effects meta-analysis was used to pool the following outcomes: complete occlusion, technical success, periprocedural morbidity/mortality, stroke rates, aneurysm recurrence/rebleed, CN palsies rates, and long-term neurological morbidity/mortality.

RESULTS

We included 29 studies with 796 PICA aneurysms. When considering all ruptured PICA aneurysms, complete occlusion rates were 97.1 % (95 % CI = 94.5-99.0 %) in the surgical group and 84.3 % (95 % CI = 73.8-92.6 %) in the endovascular group. Aneurysm recurrence occurred in 1.4 % (95 % CI = 0.3-3.3 %) after surgery and in 6.9 % (95 % CI = 3.6-10.9 %) after endovascular treatment. Overall neurological morbidity and mortality were 14.4 % (95 % CI = 8.7-21.2 %) and 9.8 % (95 % CI = 5.8-14.8 %) after surgery and 15.1 % (95 % CI = 10.5-20.2 %) and 17.1 % (95 % CI = 11.5-23.7 %) after endovascular treatment, respectively. When considering all unruptured PICA aneurysms, complete occlusion rates were 92.9 % (95 % CI = 79.5-100 %) in the surgical group and 75.7 % (95 % CI = 45.4-97.1 %) in the endovascular group. Overall long-term good neurological outcome rates were 91.5 % (95 % CI = 74.4-100 %) in the surgical series and 93.3 % (95 % CI = 82.7-99.5 %) in the endovascular group.

CONCLUSIONS

Our meta-analysis demonstrated that both treatment modalities are technically feasible with high rates of technical success and effective with sufficient long-term aneurysm occlusion rates. Our data suggest that surgery is associated with superior angiographic outcomes. While endovascular therapy could be a reasonable first-line treatment option for proximal PICA aneurysms, surgery remains a highly effective first-line choice for distal PICA aneurysms. These findings should be considered when deciding the best therapeutic strategy.

Treatment Strategy for Isolated Posterior Inferior Cerebellar Artery Dissection

OBJECTIVE

Isolated dissections that develop on the posterior inferior cerebellar artery (PICA) require intensive treatment because of their potential fatality. However, because of the rarity of these dissections, the optimal treatment has not yet been established.

METHODS

We retrospectively reviewed the clinical records of all patients who underwent any PICA dissection treatment in our institute over the last 4 years. Ten patients were enrolled, including 7 patients with subarachnoid hemorrhage (SAH) and 3 with PICA territory infarction. Dissection was seen at the proximal portion in 8 patients, whereas the remaining 2 patients showed distal PICA dissecting aneurysms.

RESULTS

Among the 7 patients with hemorrhage, 5 were actively treated (trapping and bypass, 2 patients; surgical clipping, 1 patient; coil embolization, 2 patients). Conservative management was performed in the other 2 patients. Among the 3 patients with infarction, 2 received conservative treatment. Endovascular treatment was performed in 1 patient, who showed rapid progression, aneurysm formation, and conversion to massive SAH within 10 days after the initial attack. Although 7 patients showed relatively good outcomes (modified Rankin Scale score, ≤2) after 30 days of follow-up, 1 patient had a final modified Rankin Scale score of 3. In addition, the other 2 patients (1 in each group) died as a result of major SAH.

CONCLUSIONS

Given the dynamic clinical course and potential fatality of PICA dissection, meticulous evaluation, intensive treatment with a diverse range of modalities, and proper follow-up are required for patients with PICA dissection to achieve favorable outcomes.

Ruptured Distal Posterior Inferior Cerebellar Artery (PICA) Aneurysms Associated with Cerebellar Arterial Venous Malformations (AVMs): A Case Series and Review of the Literature Demonstrating the Need for Angiographic Evaluation and Feasibility of Endovascular Treatment

OBJECTIVE

The characteristics, diagnosis, and preferred management strategies for distal posterior inferior cerebellar artery (PICA) aneurysms associated with cerebellar arteriovenous malformation (AVMs) are poorly understood. We present a case series with attention to aneurysm angioarchitecture, diagnostic imaging, treatment approaches, and a thorough review of the literature. With this information, we demonstrate a specific anatomical pattern for these aneurysms, an underreported need for conventional digital subtraction angiography (DSA) during evaluation, along with the utility of endovascular treatment with liquid embolic agents.

METHODS

Neurosurgical patients from 2005 to 2016 were reviewed to identify PICA aneurysms along with distal PICA aneurysms. Details of their presentation, imaging studies, associated AVMs and treatment were recorded. A thorough literature search of previous case series and case reports of distal PICA aneurysms with and without associated small cerebellar AVMs was performed with PubMed and Google Scholar.

RESULTS

Thirty-four patients with PICA aneurysms were identified at our institution, 12 of which were in a distal segment. All 12 of these patients underwent DSA as a part of their evaluation. Of the 12 patients with distal PICA aneurysms, 9 presented with subarachnoid hemorrhage and intraventricular hemorrhage. Five of these patients had a small occult cerebellar AVM. All nine patients presenting with a ruptured distal PICA aneurysm had a Fischer grade 4 subarachnoid hemorrhage. Of the five patients with a small occult cerebellar AVM, the AVM nidus was missed on computed tomography angiogram (CTA) interpretation but easily visualized with DSA. CTA followed by DSA with concurrent endovascular treatment was performed in 9 of the 12 patients with distal PICA aneurysms. Two of the 12 patients were treated with microsurgical clip ligation, and one mycotic aneurysm was identified and treated with antibiotics. Parent vessel sacrifice was used distal to the aneurysm in all 5 associated AVM cases with liquid embolic agents as well as AVM embolization in 3 of the 5 cases. Fifty-one well-described case reports of distal PICA aneurysms associated with small cerebellar AVMs have been reported in the literature. A total of 12 well-described case series of distal PICA aneurysms that comment on associated AVMs describe an associated small cerebellar AVM incidence of 4%-50%. In our case series, the incidence of an associated small cerebellar AVM with a distal PICA aneurysm was 42%.

CONCLUSIONS

In cases of distal PICA aneurysms, there is a frequent association of a small cerebellar AVM. In our series, CTA was an inadequate diagnostic study to identify the associated AVM, and DSA was necessary to definitely visualize the AVM nidus. Endovascular treatment of the aneurysm and AVM with the use of liquid embolic agents was a feasible and useful management strategy.

Endovascular treatment of posterior inferior cerebellar artery aneurysms: a 7-year single-center experience

Aim

To report our experience with endovascular treatment of posterior inferior cerebellar artery (PICA) aneurysms.

Methods

Between January 2007 and December 2014, 40 patients with 42 PICA aneurysms were treated with endovascular embolization at our institution. Twenty-eight patients had 29 saccular aneurysms and 12 patients had 13 fusiform/dissecting aneurysms. The endovascular modalities were: (1) selective occlusion of the aneurysm with or without stent assistance (n=19); (2) occlusion of the aneurysm and the parent artery (n=22); and (3) occlusion of the aneurysm including the vertebral artery and PICA origin (n=1). Specifically, selective embolization was performed in 93.3% of aneurysms (14/15) proximal to the telovelotonsillary segment.

Results

Immediate angiographic results included 31 complete occlusions (74%), 3 nearly complete occlusions (7%), and 8 incomplete occlusions (19%). Mean follow-up of 20 months in 31 aneurysms showed 27 stable results, 3 further thromoboses, and 1 recurrence. Final results included 27 complete occlusions (87.1%) and 4 incomplete occlusions (12.9%). There were 5 overall procedural-related complications (12.5%), including 1 infarction (2.5%) and 4 intraprocedural ruptures (10.0%). Procedure-related morbidity and morbidity was 5.0% (2/40) and 2.5% (1/40), respectively. Clinical outcome was excellent (Glasgow Outcome Scale 5 in 31 of 33 patients at long-term follow-up).

Conclusions

PICA aneurysms may be effectively treated by different endovascular approaches with favorable clinical and radiologic outcomes. Further studies are required to compare the safety and efficacy of endovascular treatment with open surgery.

Risk Score for Neurological Complications After Endovascular Treatment of Unruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE

Procedure-related neurological complications are common after endovascular treatment of unruptured intracranial aneurysms. We aimed to develop a score to quantify individual patient risk.

METHODS

We retrospectively analyzed consecutive patients who underwent endovascular treatment for unruptured intracranial aneurysms between January 2012 and September 2015. After excluding those who lost to follow-up and those with fusiform unruptured intracranial aneurysms, included patients were randomly divided into a derivation group (60%) and a validation group (40%). A neurological complication was defined as any transient or permanent increase in the modified Rankin Scale score after aneurysm embolization. A risk score for neurological complications was derived from multivariable logistic regression analyses in the derivation group and validated in the validation group.

RESULTS

Overall, 1060 patients were included (636 in the derivation group and 424 in the validation group). The incidence of neurological complications was 5.5% (95% confidence interval, 3.8%-7.4%). A 3-point risk score (S-C-C) was derived to predict neurological complications (size [≥10 mm=1], core areas [yes=1], and cerebral ischemic comorbidity [yes=1]). The incidence of neurological complications varied from 2.2% in 0-point patients to 25.0% in 3-point patients. The score demonstrated significant discrimination (C-statistic, 0.714; 95% confidence interval, 0.624-0.804) and calibration (McFadden R(2), 0.102) in the derivation group. Excellent prediction, discrimination, and calibration properties were reproduced in the validation group.

CONCLUSIONS

One in 20 patients will develop neurological complications after endovascular treatment of unruptured intracranial aneurysms. The S-C-C score may be useful for predicting these adverse outcomes based on variables in daily practice.