Proximal Posterior Inferior Cerebellar Artery Research Articles

Challenging Endovascular Treatment of Ruptured Proximal Posterior Inferior Cerebellar Artery Aneurysm: A Case Report

Highlight: Posterior inferior cerebellar artery (PICA) aneurysms are rare in occurence. The endovascular management of PICA aneursysms is challenging due to anatomical difficulties in accessing the site. The rebleeding of PICA aneurysms, although rare than other intracranial anurysms, may still happen and must be considered in their management ABSTRACT Introduction Aneurysms of the posterior inferior cerebellar artery (PICA) are rare clinical entities with a lower risk of rupture than other intracranial locations. This makes managing PICA aneurysms challenging and important for neurointerventionists to understand. In this case report, we looked at a rare case of PICA aneurysm with post-coiling rebleeding. Case: We reported a 51-year-old female with complaints of dizziness and vomiting. The patient was found to be hypertensive and a neurologic assessment revealed neck stiffness and left hemiparesis. A computed tomography (CT) scan of the head indicated subarachnoid hemorrhage. CT angiography (CTA) showed an aneurysm at the right proximal PICA. Although endovascular coiling was performed, the patient rebleed one month later. Following the insertion of the second coil, successful embolization was achieved, and the patient showed clinical improvement. Conclusion: PICA aneurysms require careful endovascular management, considering the difficulty of access due to their anatomical location. An understanding of its proper management is of paramount importance to reducing mortality.

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

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. 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. 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). 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.

Ondine's curse: clinical presentation with diaphragmatic pacing and spontaneous respiratory recovery. Illustrative case.

The complexity of posterior fossa surgery can often lead to rare complications due to the anatomy involved. Vestibular schwannoma resection is a common pathology in the posterior fossa, often requiring surgical intervention. Given the proximity of this space to the brainstem, cranial nerve VII/VIII complex, and posterior inferior cerebellar artery (PICA), neurovascular complications are not infrequent. A rare vascular complication from this surgical approach is a lateral medullary infarction from injury to the lateral medullary segment of the proximal PICA, leading to central hypoventilation syndrome (CHS). This report presents a unique case of a 51-year-old man who underwent a retrosigmoid craniectomy for resection of a vestibular schwannoma. Following surgery, the patient was unable to be weaned off the ventilator and was noted to become apneic while he slept, a clinical picture consistent with Ondine's curse. This report discusses the anatomical considerations of this surgical corridor leading to this complication and the management of a patient with acquired Ondine's curse and reviews the scarce literature on this uncommon cause of acquired CHS.

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

BackgroundIn 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. MethodsForty-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. ResultsMost 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. ConclusionsMicrosurgery 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.

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

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. 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. 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. 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.

Morphological characteristics associated with ruptured intracranial vertebral artery dissecting aneurysms

ObjectiveMorphological risk factors for the rupture of intracranial vertebral artery dissecting aneurysms (IVADAs) have not been well characterized. In this study, we aim to identify morphological characteristics associated with IVADA...

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

BackgroundSurgical 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...

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

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. 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. 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. 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.

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

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

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

BackgroundRuptured 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...

Far-Lateral Craniotomy for Posterior Inferior Cerebellar Artery to Occipital Artery Bypass: 2-Dimensional Operative Video.

Posterior inferior cerebellar artery (PICA) aneurysms are infrequent compared with other intracranial aneurysms and are more commonly distal in origin (35% of PICA aneurysms are distal vs 6.5% of other aneurysms). This makes PICA aneurysms a surgical challenge that requires careful consideration of the patient's angiographic anatomy and perfusion needs before deciding on the appropriate intervention. This patient had a highly calcified left PICA p2 segment aneurysm, which was not favorable for endovascular intervention. An end-to-side anastomosis of the occipital artery to the p3 PICA segment was performed. This anastomosis was achieved with 11-0 suture. A permanent clip was then placed along the vertebral artery occluding both the proximal PICA and the aneurysm. Indocyanine green angiography was performed to demonstrate bypass and PICA patency. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Far Lateral Craniotomy for Posterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Bypass and Trapping of Posterior Inferior Cerebellar Artery Aneurysm: 3-Dimensional Operative Video.

Posterior inferior cerebellar artery (PICA) aneurysms account for 3% to 4% of all intracranial aneurysms with an unusually high predilection towards a nonsaccular morphology making microsurgical clipping or endovascular reconstruction of the parent artery difficult. The management of these complicated aneurysms may require revascularization procedures for flow preservation with aneurysm trapping. Recently, there is an increasing inclination towards intracranial-intracranial (IC-IC) bypasses over traditional extracranial donors. This video demonstrates a side-to-side PICA-PICA in situ bypass with trapping of an unruptured incidental right p1-PICA aneurysm. Radiological lesion progression and presence of dysplastic morphological characteristics prompted surgical management. The aneurysm was not amenable to clip reconstruction due to the dysplastic PICA segment and lack of a discernable neck. Institutional Review Board approval and patient consent were sought. With patient in three-quarter-prone position, a right far lateral craniotomy was performed. A left-to-right p3-p3 PICA bypass was completed. The aneurysm was clipped along with proximal PICA at its takeoff from vertebral artery. Indocyanine green videoangiography revealed complete occlusion of aneurysm and proximal PICA and a patent anastomosis with distal right PICA flow. Postoperatively, patient recovered with no new neurological deficits. Dolichoectatic posterior circulation aneurysms are not readily amenable to clip reconstruction. PICA-PICA in situ bypass is an elegant alternative to existing extracranial-intracranial revascularization constructs (occipital artery to PICA).1 There is lower neurological morbidity associated with IC-IC bypass vs PICA reimplantation due to the deep surgical corridor and its proximity to lower cranial nerves. Additionally, in this patient endovascular occlusion posed a higher risk of thrombotic complications and postprocedural cerebellar edema with brainstem compression.2.

Revascularization treatment for complex proximal posterior inferior cerebellar artery aneurysms

Objective To evaluate the clinical effect of revascularization on the treatment of complex proximal posterior inferior cerebellar artery (PICA) aneurysms. Methods A retrospective analysis was conducted on 10 cases (accounting for 5.1% of 10/198 cases of PICA aneurysm admitted during the same period) of complex proximal PICA aneurysms (10 aneurysms) who were admitted to Neurosurgical Department of Tianjin Huanhu Hospital from June 2008 to January 2018. According to the morphological characteristics and collateral circulation of aneurysms, various ways of revascularization were undergone. Eight cases underwent occipital artery (OA)-PICA anastomosis + aneurysm trapping; vertebral artery (VA) occlusion + OA-PICA anastomosis was performed in 1 case; aneurysm depression and PICA in situ anastomosis was performed in 1 case. The patency of anastomotic vessels and postoperative complications were observed after operation and the patients' outcomes were evaluated with modified Rankin scale (mRS). Results Ten cases successfully underwent the blood flow reconstruction. Intraoperative fluorescein angiography revealed the patency of anastomotic vessels. Two cases developed hoarseness post operation and fully recovered to normal after treatment. One patient developed dyspnea and pulmonary infection 3 days post operation and fully recovered to normal after treatment. Ten cases were followed up effectively. The follow-up period was 3-118 months after operation. No recurrent or ruptured aneurysms were found in the follow-up period. One patient died of cerebral hemorrhage because of hypertension after 12 months. Ventriculoperitoneal drainage was performed in 1 case of hydrocephalus. Nine cases of anastomotic vessels were patent and 1 case showed occlusion. All aneurysms disappeared. The score of mRS was 0 in 8 cases, 1 in 1 and 6 in 1. Conclusions Depending on the morphological characteristics and collateral circulation, different revascularization techniques are selected. Revascularization is an effective method for the treatment of complex proximal PICA aneurysms in terms of relief of space-occupying effect and removal of aneurysms. Key words: Intracranial aneurysm; Neurosurgical procedures; Prognosis; Posterior inferior cerebellar artery; Revascularization

Relationship between the Angle of the Posterior Inferior Cerebellar Artery and Cardioembolic Stroke

BackgroundIn patients with unilateral posterior inferior cerebellar artery (PICA) territory infarction, the absence of relevant vessel stenosis may make it difficult to determine the etiology of the infarction. The incidence of cardioembolic (CE) infarction and the factors associated with infarction in such patients remains largely unknown. We hypothesized that the PICA angle would affect the flow direction of embolic sources. Thus, we analyzed the association between high-risk CE sources and the PICA angle. MethodsPatients with an isolated unilateral PICA territory infarction without relevant vessel stenosis who were admitted between 2014 and 2017 were included from the Korea University Stroke Registry, which includes data from 3 university hospitals. We classified patients according to the presence of CE sources. For each case, we measured the angle between the vertebral artery (VA) and the proximal PICA. ResultsIn all, 71 patients met the final study entry criteria. Multivariable analysis showed that the PICA angle was independently associated with the risk of a CE source. The optimal cut-off value using Youden's index was 89°. We classified the PICA shape based on the optimal cut-off value. A CE source was identified in 83.3% of cases in which the PICA angle exceeded 89°. ConclusionsThe angle between the PICA and VA was an independent predictor of unilateral PICA stroke with high-risk CE sources without relevant artery stenosis, suggesting that an angle greater than 89° could be a new image marker for determining the stroke subtype.

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

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

Coil Embolization Results of the Ruptured Proximal Posteriori Inferior Cerebellar Artery Aneurysm: A Single-Center 10 Years' Experience

To report a single-center experience with endovascular treatment of ruptured proximal posterior inferior cerebellar artery (PICA) aneurysms. Between January 2007 and December 2016, among 1403 patients with aneurysmal subarachnoid hemorrhage, 15 with ruptured proximal PICA aneurysms underwent endovascular embolization at our institution. Aneurysmal obliteration with a single microcatheter was performed in 9 patients. Additional microcatheter or stent-assisted coil embolization was performed in 4 patients and parent artery occlusion in 2 patients. Immediate angiographic results showed 10 complete occlusions (66.7%, 10/15). Five patients showed incomplete occlusion (remnant neck in 4 patients, remnant aneurysm in 1). Of those, 2 patients experienced recurrence and required conversion to microsurgical clipping. The remaining 2 patients remained in relatively stable condition. Procedure-related complications occurred in 3 patients (20%, with thromboembolic complications in 2 patients and intraprocedural rupture in 1). Clinical outcome was excellent: Glasgow Outcome Score 4 or 5 in 12 of 15 patients (80%). There was no rebleeding during follow-up. Ruptured proximal PICA aneurysms may be effectively treated with endovascular coil embolization. A variety of coil embolization techniques are required to obliterate an aneurysm without parent artery occlusion. Given that recurrence is possible, follow-up is required. Surgical clipping can be performed for recurrence with a relatively low risk of complications, because the aneurysm is unruptured. Coil embolization of a proximal PICA aneurysm in the acute phase can be a good treatment modality with good patient outcomes.

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

ObjectiveSurgical 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.MethodsThe parent artery and microcatheter for easier navigation and the embolization technique for stable coiling were identified.ResultsThis 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.ConclusionCoil 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.

Endovascular treatment of ruptured pica aneurysms and association with its extradural origin: A single-center experience.

Background:Posterior inferior cerebellar artery (PICA) like other intracranial arteries is prone to aneurysm formation. Aneurysms usually arise from the vertebral artery (VA)—PICA junction and the proximal segment of the PICA. The surgical clipping of PICA aneurysms can be challenging and carries a potentially significant risk of morbidity and mortality. Experience with endovascular therapy has been limited to a few studies; however, the use of endovascular therapy as an alternative treatment to surgery has been increasing. We present our experience of last 5 years in treating the ruptured PICA aneurysms.Materials and Methods:A total of 11 patients with PICA aneurysms, out of them 7 were at proximal PICA, 2 at the vertebral-PICA junction, and 1 each at mid and distal PICA, underwent endovascular treatment at our institution between 2011 and 2016.Results:All the patients presented with an acute intracranial hemorrhage, confirmed on CT head. Most of the aneurysms were at proximal PICA (anterior and lateral medullary segments) with the partial incorporation of PICA origin in the sac. Low origin of PICA was seen in 7 (out of 11) cases, out of these cases, 5 had proximal PICA, aneurysm, and one (n = 1) had VA-PICA, junction aneurysm (1/7) and. one distal PICA aneurysm. There were seven proximal PICA aneurysms, and out of them, parent vessel occlusion was done in six and selective coiling in one (n = 1) case. From seven (n = 7) proximal PICA aneurysms, there were five cases of low origin and rests showed normal course and origin. Two (n = 2) junctional aneurysms were treated with simple coiling. Low origin was seen in right VA-PICA junction aneurysm. Endovascular treatment of all the 11 aneurysms was successful. The treatment consisted of selective aneurysm coiling in four (36.3%) patients and aneurysm with parent vessel trapping in seven patients (63.6%). Out of these seven patients, in one (n = 1) patient where aneurysm was distal PICA, glue embolization was done. There was no intra-procedural rupture/contrast extravasation or any thrombo-embolic complications. Follow-up studies ranged from 6 months to 5 years.Conclusion:Endovascular therapy of ruptured proximal PICA aneurysms is possible and safe with the use of adjuvant devices and should be considered as first-line treatment.

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

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. 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 to2009. 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). 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.

Multidisciplinary management for the treatment of proximal posterior inferior cerebellar artery aneurysms

Objectives: Aneurysms of the proximal posterior inferior cerebellar artery (PICA) are rare. The management of proximal PICA aneurysms is challenging with either surgical or endovascular treatment. We report our successful experience of treating PICA aneurysms with a multimodal approach.Methods: Of 2382 treated aneurysms, 22 aneurysms in 21 patients (male:female 8:13, mean age 48.9 years) were enrolled from March 1998 to December 2015. We treated the aneurysms with a multimodal approach and performed angiography to examine aneurysm regrowth at the 12 months follow-up. Clinical outcomes were evaluated based on the modified Rankin Score (mRS) at the time of discharge and 12 months postoperatively. The treatment modality was mainly dependent on the character of the aneurysms and the clinical presentation of the patients.Results: Microsurgery was performed in seven patients, which entailed proximal occlusion with distal revascularization in two and microsurgical clipping in five. Endovascular treatment was performed in 10 patients because of a serious medical condition, or vertebral artery (VA)/ or PICA tortuosity. Four were treated with coil embolization and six with stent or balloon-assisted coil embolization. Combined surgical and endovascular treatment was applied in four patients. They were treated with distal revascularization followed by occlusion with coils of the aneurysm-incorporated PICA. All patients achieved complete cure of the PICA aneurysms without complications except for one case of cerebrospinal fluid (CSF) leakage.Discussion: Endovascular and microvascular neurosurgeons should work closely in managing these challenging problems. Neurosurgeons should consider multimodal treatment in these cases including trapping after occipital artery (OA)-PICA bypass.