Treatment and Outcomes Among 102 Posterior Inferior Cerebellar Artery Aneurysms: A Comparison of Endovascular and Microsurgical Clip Ligation

Strategies and outcomes of endovascular treatment of posterior inferior cerebellar artery aneurysms: a single center experience

To explore safe and reliable strategies and outcomes of endovascular procedures in the treatment of posterior inferior cerebellar artery (PICA) aneurysms. Retrospectively reviewed and analyzed the cases of PICA aneurysms that undergone endovascular therapy from July 2017 through January 2022 in our neurosurgical center, as well as outcomes of long-term follow-up. Total 24 cases were enrolled. Majority of the PICA aneurysms (87.5%, 21/24) presented initially with subarachnoid hemorrhage (SAH) and only 3 cases were not ruptured when they were clinically diagnosed as PICA aneurysms. The patients were endovascularly given either aneurysm occlusion with selective coils (12 cases), embolization of aneurysms and parent arteries (7 cases: 3 cases with coils and 4 cases with Onyx liquid embolic agent), or stent-assisted coiling of the aneurysms (5 cases). One patient, who had comorbidity of intracranial hemorrhage and severe cerebral vasospasm, declined further post-surgery therapy, and discharged from the hospital with anticipation of poor outcome. The rest 23 patients were followed up for 3-24 months with a recurrence rate of 17.4% (4/23). Endovascular procedure of embolizing PICA aneurysms with selective coils or stent-assisted coils is feasible, safe, and reliable. Simplified embolization of the aneurysms or occlusion of the parent artery is recommended as the first choice for the ruptured and bleeding PICA aneurysms.

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.

Far-lateral approach without C1 laminectomy for microsurgical treatment of vertebral artery and proximal posterior inferior cerebellar artery aneurysms: Experience from 48 patients

Background

In the endovascular era, most of vertebral artery (VA) and posterior inferior cerebellar artery (PICA) aneurysms were mainly treated with endovascular procedures. This study aimed to demonstrate the microsurgical treatment via the far-lateral approach without C1 laminectomy and its clinical outcomes.

Methods

Forty-eight patients with VA and proximal PICA aneurysms treated by microsurgery through the far-lateral approach without C1 laminectomy, between January 2016 and June 2021, were retrospectively evaluated.

Results

Most patients (87.5%) presented with subarachnoid hemorrhage. Grading at presentation was poor in 41.7%. The rates of VA dissecting aneurysms, saccular aneurysms of the VA-PICA junction, and true PICA saccular aneurysms were 54.2, 18.7, and 14.6%, respectively. All aneurysms were located above the lower margin of the foramen magnum. The far-lateral approach without C1 laminectomy was successfully used in all patients without residual aneurysms. Various surgical strategies were applied depending on the characteristics of the aneurysm. Good outcomes 3 months postoperatively were achieved in 77.1% and 89.3% for the overall and good-grade groups, respectively.

Conclusions

Microsurgery is a safe and effective treatment of VA and proximal PICA aneurysms. Moreover, the far-lateral approach without C1 laminectomy was adequate and effective for aneurysms located above the lower border of the foramen magnum.

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.

Surgical and Endovascular Treatment of Saccular Posterior Inferior Cerebellar Artery Aneurysms: Systematic Review and Meta-Analysis

OBJECTIVE

The optimal treatment modality for saccular aneurysms of the posterior inferior cerebellar artery (PICA) remains unclear. A previous meta-analysis on the topic included a heterogenous study population, limiting the conclusions that can be drawn from its results. The aim of this study was to perform a systematic review and meta-analysis to compare outcomes of microsurgical and endovascular treatment (EVT) of these aneurysms.

METHODS

A search of 4 online databases was performed for studies describing the management of saccular PICA aneurysms. The primary outcome was complete aneurysm occlusion. Data were also collected on neurologic outcomes, cranial nerve palsies, and requirement for re-treatment. A random effects model was used for calculation of pooled proportions. Our protocol was registered with PROSPERO (CRD42021232784).

RESULTS

A total of 17 studies were included in the final analysis, reporting the treatment outcomes of 455 aneurysms, with a mean follow-up of 20 months. The pooled occlusion rates were 94.8% (95% confidence interval [CI] 90.6%-97.8%) for surgical treatment and 69.1% (95% CI 55.0%-81.7%) for EVT. Pooled rates of good neurologic outcome (modified Rankin scale score ≤2, Glasgow Outcome Scale score ≥4) at last follow-up were 78.1% (95% CI 67.4%-87.1%) for surgery and 77.6% (95% CI 67.9%-86.0%) for EVT.

CONCLUSIONS

This meta-analysis demonstrates that in the treatment of saccular PICA aneurysms, microsurgical clipping results in superior angiographic outcomes, similar functional outcomes, but higher rates of lower cranial nerve palsy compared with EVT. Further studies are required to assess the duration and severity of cranial nerve palsies following surgical treatment, and long-term aneurysm occlusion and the requirement for re-intervention following EVT.

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.

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.

Microsurgical Treatment for a Ruptured Posterior Inferior Cerebellar Artery Aneurysm: A 3-Dimensional Surgical Video and Anatomic Landmarks Review

Aneurysms are the most frequent issue for the posterior inferior cerebellar artery (PICA). PICA aneurysms account for 1.4% to 4.5% of all intracranial aneurysms.^1-3 Although the majority of PICA aneurysms arise from their junction with the vertebral artery, they can be found in any of 5 segments.^4,5 Although PICA is more prone to form nonsaccular aneurysms than other intracranial arteries, ruptured aneurysms are usually saccular.⁶ Nearly all PICA aneurysms are located intracranially, above the foramen magnum. Extracranial PICA aneurysms are rare, with few reports in literature.⁷ Microsurgical clipping remains a good treatment alternative for these aneurysms. Higher risk of rerupture has even been reported with embolization of the distal PICA aneurysm with parent artery preservation.⁸ Here we present the case of a 64-year-old male patient who presented right after a thunderclap headache, followed by a temporary loss of consciousness and disorientation. He was diagnosed with a modified Fisher 4 and Hunt and Hess 2 subarachnoid hemorrhage and found to have a partially thrombosed left PICA saccular aneurysm of the caudal loop just below the foramen magnum. The lesion was approached via a midline suboccipital craniotomy with C1 laminectomy. Microsurgical clipping of the aneurysm was performed without any complications (Video 1). Postoperatively, the patient was discharged without neurologic deficits. We present the first surgical video of the necessary steps in order to perform a microsurgical clipping of an extracranially located caudal loop PICA aneurysm through a midline suboccipital craniotomy with C1 laminectomy.

Third Nerve Palsy Due to Intracranial Aneurysms and Recovery after Endovascular Coiling

INTRODUCTION

The modality of treatment of third nerve palsy (TNP) associated with intracranial aneurysms remains controversial. While treatment varies with the location of the aneurysm, microsurgical clipping of PComm aneurysms has generally been the traditional choice, with endovascular coiling emerging as a reasonable alternative.

METHODS

Patients with TNP due to an intracranial aneurysm who subsequently underwent treatment at a mid-sized Canadian neurosurgical center over a 15-year period (2003-2018) were examined.

RESULTS

A total of 616 intracranial aneurysms in 538 patients were treated; the majority underwent endovascular coiling with only 24 patients treated with surgical clipping. Only 37 patients (6.9%) presented with either a partial or complete TNP and underwent endovascular embolization; of these, 17 presented with a SAH secondary to intracranial aneurysm rupture. Aneurysms associated with TNP included PComm (64.9%), terminal ICA (29.7%), proximal MCA (2.7%), and basilar tip (2.7%) aneurysms. In general, smaller aneurysms and earlier treatment were provided for patients for ruptured aneurysms with a shorter mean interval to TNP recovery. In the endovascularly treated cohort initially presenting with TNP, seven presented with a complete TNP and the remaining were partial TNPs. TNP resolved completely in 20 patients (55.1%) and partially in 10 patients (27.0%). Neither time to coiling nor SAH at presentation were significantly associated with the recovery status of TNP.

CONCLUSION

Endovascular coil embolization is a viable treatment modality for patients presenting with an associated cranial nerve palsy.

The Glossopharyngo-Cochlear Triangle-Part II: Case Series Highlighting the Clinical Application to High-Riding Posterior Inferior Cerebellar Artery Aneurysms Exposed Through the Extended Retrosigmoid Approach

BACKGROUND

Use of the far lateral transcondylar (FL) approach and vagoaccessory triangle is the standard exposure for clipping most posterior inferior cerebellar artery (PICA) aneurysms. However, a distal PICA origin or high-lying vertebrobasilar junction can position the aneurysm beyond the vagoaccessory triangle, making the conventional FL approach inappropriate.

OBJECTIVE

To demonstrate the utility of the extended retrosigmoid (eRS) approach and a lateral trajectory through the glossopharyngo-cochlear triangle as the surgical corridor for these cases.

METHODS

High-riding PICA aneurysms treated by microsurgery were retrospectively reviewed, comparing exposure through the eRS and FL approaches. Clinical, surgical, and outcome measures were evaluated. Distances from the aneurysm neck to the internal auditory canal (IAC), jugular foramen, and foramen magnum were measured.

RESULTS

Six patients with PICA aneurysms underwent clipping using the eRS approach; 5 had high-riding PICA aneurysms based on measurements from preoperative computed tomography angiography (CTA). Mean distances of the aneurysm neck above the foramen magnum, below the IAC, and above the jugular foramen were 27.0 mm, 3.7 mm, and 8.2 mm, respectively. Distances were all significantly lower versus the comparison group of 9 patients with normal or low-riding PICA aneurysms treated using an FL approach (P < .01). All 6 aneurysms treated using eRS were completely occluded without operative complications.

CONCLUSION

The eRS approach is an important alternative to the FL approach for high-riding PICA aneurysms, identified as having necks more than 23 mm above the foramen magnum on CTA. The glossopharyngo-cochlear triangle is another important anatomic triangle that facilitates microsurgical dissection.

Microneurosurgical Management of Posterior Inferior Cerebellar Artery Aneurysms: Results of a Consecutive Series

Aneurysms of the posterior inferior cerebellar artery (PICA) are uncommon. The complex anatomy of PICA and its intimate relationships with medulla, lower cranial nerves, and jugular tubercle makes the surgical treatment of these aneurysms fascinating. The reported is study aimed at a critical review of the overall results of a personal series of PICA aneurysms, treated by the senior author, R. Galzio. Demographics, charts, videos, outcome, and follow-up of a cohort of PICA aneurysms managed in the last 10 years were retrospectively analyzed, focusing only upon those treated with microneurosurgery. Twenty-five patients, harboring a single aneurysm, were operated on. Fifteen aneurysms were ruptured. Nineteen were proximal, all of these being been treated through a far-lateral approach. Trans-condylar or trans-tubercular variants were rarely necessary and however reserved to peculiar cases. Twenty-three aneurysms underwent direct treatment consisting of clip ligation. At 6-month follow-up, 60% of patients had a modified Rankin Score (mRS) of 0-2. Given the high anatomical variability of both PICA and patients' bony anatomy, a case-by-case meticulous preoperative imaging evaluation is mandatory for the choice of the most suitable and tailored surgical corridor which, in turn, is pivotal to achieve the best outcome.

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.

Institutional Experience of Microsurgical Management in Posterior Circulation Aneurysm

Introduction:

Posterior circulation aneurysm constitutes 15%–20% of all intracerebral aneurysms. With the advancement of endovascular techniques, the microsurgery for posterior circulation aneurysms has been pushed back a little. Even the International Subarachnoid Aneurysmal Trial gave support to the concepts of endovascular procedures, but microsurgical modality should not be discouraged. We present our institutional experience of microsurgical techniques on posterior circulation aneurysms.

Materials and Methods:

We performed a retrospective analysis of 37 patients of posterior circulation aneurysm from 2015 to 2019, referred to Bantane Hospital, Japan. We included all posterior circulation aneurysms such as basilar tip, basilar trunk, and vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysms, admitted and treated with clipping or bypass and trapping. We assessed the outcome as measured by modified Rankin Score (mRS), complications, and mortality.

Results:

Out of 37 patients, 10 cases were a basilar tip, one case was the basilar trunk, and 26 cases were VA-PICA aneurysm. Intraoperatively, neuromonitoring, indocyanine green dye, dual-image videoangiography (DIVA), and neuro endoscope were used. Two patients of basilar tip aneurysm developed third cranial nerve paresis and six patients of VA-PICA aneurysm developed lower cranial nerve paresis which resolved spontaneously. All the patients were discharged with mRS of 0 or 1. No mortality was recorded in our study.

Conclusion:

Microsurgical clipping of posterior circulation aneurysm is safe in unruptured aneurysm with a very low risk of mortality and morbidity under experienced hands. All postoperative complications in our study were transient and resolved with time with no residual deficits. Preoperative simulation, intraoperative neuromonitoring, DIVA, and neuro endoscope help achieve complete obliteration of aneurysmal sac and avoid complications.

Multidisciplinary Treatments of True Posterior Inferior Cerebellar Artery Aneurysms: Single-Center Retrospective Study and Treatment Algorithm

BACKGROUND

True posterior inferior cerebellar artery (PICA) aneurysms outside the vertebral artery-PICA region are rare, with approximately 30 cases reported in just a few papers; no treatment paradigm has been advocated. The objective of this study was to present detailed clinical features and outcomes for several treatments for true PICA aneurysms and suggest an algorithm for treatment strategies.

METHODS

We retrospectively analyzed outcomes of patients treated for PICA aneurysms with microsurgical and endovascular treatments. We also investigated the influence of several factors on the modified Rankin Scale score.

RESULTS

Cases with PICA aneurysms (n = 36) outside the vertebral artery-PICA region were identified angiographically. Aneurysm locations included anterior medullary (n = 7), lateral medullary (n = 10), tonsillomedullary (n = 4), telovelotonsillar (n = 12), and cortical (n = 3) segments of the PICA. Aneurysm morphology was as follows: dissecting: 22; fusiform: 6; and saccular: 8. On multivariate analysis, age (P = 0.028) and lack of vermian infarction (P =0.037) were associated with a significantly better prognosis. Prognosis was not significantly different for the 5 aneurysm locations and among the 4 treatment groups: clipping/coiling, trapping/parent artery occlusion, trapping/parent artery occlusion + bypass, and observation including external ventricular drainage.

CONCLUSIONS

This study suggests that factors associated with significantly better prognosis include age, clip/coil treatments, and no vermian infarction complication. A treatment algorithm for true PICA aneurysms was supported according to pretreatment H and K grade, PICA segments, aneurysm morphology, and 3 types of ischemia linked to the brainstem, cerebellar hemisphere, or vermis.

Surgical Management and Outcomes of Aneurysms of Posterior Inferior Cerebellar Artery: Location-Based Approaches with Review of Literature

Background  Posterior inferior cerebellar artery (PICA) is a tortuous, variable, and uncommon site for aneurysms. Surgical management of PICA aneurysms involves careful selection of approach based on the location of the aneurysm and meticulous dissection of the neurovascular structures and perforators.

Materials and Methods  We did a retrospective review of all the PICA aneurysms operated at our institute in the past 10 years along with the site, presentation, and approach used for the same. Preoperative World Federation of Neurosurgical Society scores and follow-up modified Rankin scores (mRS) were also evaluated. During the same period, data for intervention cases of PICA aneurysm were also collected with follow-ups for a comparative analysis.

Results  A total of 20 patients with 21 PICA aneurysms were reviewed. All the reviewed cases presented with subarachnoid hemorrhage, and the most common location was the lateral medullary segment and vertebral artery (VA)–PICA junction. Midline approaches were used for distal PICA cases, with far-lateral approach reserved for anterior medullary/VA–PICA junction. No lower cranial nerve palsies were recorded at follow-up. Four cases needed cerebrospinal fluid diversion and two developed cerebellar infarcts. All cases were mRS 0 to 2 at follow-up.

Conclusion  Our series compares well with some of the larger surgical series of PICA aneurysms. This may be due to early referral patterns and early surgery (<24 hours) policy at our institution. Anatomical knowledge of PICA anatomy and sound perioperative management are keys to good outcomes in these cases.

Clinical Importance of the Posterior Inferior Cerebellar Artery: A Review of the Literature

The posterior inferior cerebellar artery (PICA), with its unique anatomical complexity, is of great clinical importance and involved in many diseases including aneurysm, ischemic stroke, neurovascular compression syndrome (NVCS), arteriovenous malformation (AVM), and brain tumor. However, a comprehensive systematic review of the importance of the PICA is currently lacking. In this study, we perform a literature review of PICA by searching all the associated papers in the PUBMED database hoping to provide a better understanding of the artery. The PICA has tortuous and variable course and territory, divided into 5 segments. Various aneurysms involving PICA were not uncommon, of which the treatment is challenging. The PICA infarct typically manifests lateral medullary syndrome (LMS) and is more likely to cause mass effects. The PICA frequently compresses the medulla and the cranial nerves resulting in various neurovascular compression syndromes (NVCS). Arteriovenous malformation (AVM) fed by PICA are associated with aneurysm and dissection which have high risk of rupture and worse outcome. PICA injured by head trauma can cause fatal SAH. VA terminating in PICA probably cause Bow hunter's syndrome (BHS). The PICA supplies many brain tumors and can be used in intracerebellar chemotherapy. The PICA can be exposed and injured during surgeries especially in telovelar approach, and it also plays an important role in bypass surgeries, hinting the surgical importance of PICA. In conclusion, PICA is very important in clinical practice.

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.

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.

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.

Technical Consideration for Coiling of Ruptured Proximal Posterior Inferior Cerebellar Artery Aneurysm

Objective

Surgical obliteration of ruptured aneurysm of the proximal posterior inferior cerebellar artery (PICA) is challenging because of limited surgical accessibility. In recent years, coil embolization is the first-choice treatment for these lesions. However, coil embolization is not always easy in ruptured PICA aneurysm owing to the variable anatomical diversity of its shapes, its relationship to the parent artery, its low incidence, and accordingly, lesser neurointerventionist experience.

Methods

The parent artery and microcatheter for easier navigation and the embolization technique for stable coiling were identified.

Results

This study aimed to identify the more appropriate approach route, microcatheter, and strategies for an easier and safer, and more durable coil embolization in the treatment of lesions in the proximal PICA.

Conclusion

Coil embolization for aneurysmal subarachnoid hemorrhage due to a ruptured proximal PICA remains a challenge, but with the appropriate coiling plan, it can be treated successfully.

Thrombosed Aneurysm of the Posterior Inferior Cerebellar Artery and Lateral Medullary Ischemia as the Initial Presentation of Polyarteritis Nodosa: Case Report and Literature Review

A 27-year-old woman with a previously undiagnosed polyarteritis nodosa (PAN) developed lateral medullary stroke related to a thrombosed posterior inferior cerebellar artery (PICA)-origin aneurysm. A concurrent thrombosis of the PICA was identified on high-resolution 3-dimensional CUBE T1 magnetic resonance imaging sequence at 3 T. Body computed tomography angiography, magnetic resonance imaging-magnetic resonance angiography, and digital angiography revealed multiple tiny aneurysms of the visceral arteries and bilateral kidney infarcts. On the basis of these findings and of laboratory data, the patient was diagnosed as having PAN. Intracranial aneurysms (IAs) are extremely rare in PAN and usually manifest as subarachnoid or cerebral hemorrhage. Ischemic manifestation of small thrombosed IA is a rare occurrence. This case highlights (1) an uncommon complication in patients with PAN (16 other cases of IAs in patients with PAN found in the literature), (2) an unusual initial presentation of PAN, and (3) a thrombosed PICA-origin aneurysm responsible for an ischemic stroke and for secondary thrombosis of the parent vessel.

Surgical approach to posterior inferior cerebellar artery aneurysms

BACKGROUND

The far-lateral is a standardised approach to clip aneurysms of the posterior inferior cerebellar artery (PICA). Different variants can be adopted to manage aneurysms that differ in morphology, topography, ruptured status, cerebellar swelling and surgeon preference.

METHOD

We distinguished five paradigmatic approaches aimed to manage aneurysms that are: proximal unruptured; proximal ruptured requiring posterior fossa decompression (PFD); proximal ruptured not requiring PFD; distal unruptured; distal ruptured.

CONCLUSIONS

Preoperative planning in the setting of PICA aneurysm surgery is of paramount importance to perform an effective and safe procedure, to ensure an adequate PFD and optimal proximal control before aneurysm manipulation.

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.

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.

Unexpected Rupture of a Giant Lobulated Thrombotic Middle Cerebral Artery Aneurysm and Emergency Surgical Treatment With Thrombectomy: A Case Report and Review of the Literature

Introduction

The treatment of giant intracranial aneurysms is one of the most challenging cerebrovascular problems of neurosurgery. We report the rupture of a giant, lobulated, and almost completely thrombosed middle cerebral artery (MCA) aneurysm that is the ninth such report in the literature. We also investigated additional solutions used in the treatment of this patient.

Case Presentation

A 58-year-old man had been admitted with headache 8 years previously (in 2005), and a giant MCA aneurysm was detected. Two separate endovascular interventions were performed, and both failed. The patient began to live with the giant aneurysm. As there was a large thrombosis filling the aneurysm lumen during the previous endovascular procedures, the aneurysm was not expected to rupture. However, a rupture eventually occurred, in 2013. Even if an aneurysm is very large, lobulated, old, and almost completely thrombosed, it can suddenly bleed. During surgery on this patient, we observed severe cerebral vasospasm caused by a giant thrombosed aneurysmal rupture. Despite the complications, surgery is a life-saving treatment for this emergency when other strategies are not possible. Thrombectomy and clipping are approaches that require a great deal of courage for the neurosurgeon, in terms of entering the risky area within the aneurysm.

Conclusions

We believe that it would be more appropriate to plan for combined treatment with surgical and endovascular approaches before the emergency condition could occur.

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.

Endovascular treatment of PICA aneurysms with a Low-profile Visualized Intraluminal Support (LVIS Jr) device

OBJECTIVE

To describe the treatment of posterior inferior cerebellar artery (PICA) aneurysms with the Low-profile Visualized Intraluminal Support Device (LVIS Jr) stent.

MATERIALS AND METHODS

The databases of three institutions were retrospectively reviewed. Patients who underwent endovascular treatment of PICA aneurysms using a reconstructive technique where the LVIS Jr stent was totally or partially deployed into the PICA were included in the analysis. Clinical presentation, aneurysm and PICA sizes, procedural complications, and clinical and angiographic follow-up information was recorded and analyzed.

RESULTS

Seven patients who underwent endovascular treatment of PICA aneurysms with an LVIS Jr stent were identified. Four aneurysms were treated in the acute phase of subarachnoid hemorrhage (SAH). There were no symptomatic complications. One patient had spasm distal to the stent as a result of mechanical straightening of the vessel. One patient was treated in the acute phase of SAH and required a gycoprotein IIb/IIIa inhibitor after the stent was implanted. This patient needed to be re-treated to complete embolization. All patients had good clinical outcomes (Glasgow Outcome Scale 5). No in-stent stenosis or occlusion was seen on short-term angiographic follow-up and the aneurysms were occluded.

CONCLUSIONS

This small series suggests that the use of a reconstructive technique with the LVIS Jr stent for the treatment of PICA aneurysms is feasible, safe and effective in the short term.