Cerebral revascularization performed using posterior inferior cerebellar artery-posterior inferior cerebellar artery bypass. Report of four cases and literature review

Vertebral Artery-Posterior Inferior Cerebellar Artery (PICA) Aneurysm Treated With the PICA-to-PICA Bypass: A Case Report

Treating vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysms poses challenges because of their complex anatomy. Although endovascular treatment is commonly preferred, direct surgery offers better recovery prospects than endovascular surgery aided by bypass techniques. We present a VA-PICA aneurysm case treated with VA internal trapping, using a PICA-to-PICA bypass without direct clipping. A 64-year-old man presented with complaints of severe headache and was diagnosed with a right VA-PICA wide neck aneurysm. The PICA originated from the neck of the aneurysm. We consulted an endovascular surgeon and opted for direct clipping via the transcondylar fossa approach. During surgery, we secured and followed the right VA, identified the PICA origin, and observed the proximal neck of the aneurysm. However, securing the distal VA was challenging because the dissector was inaccessible. Instead of direct clipping, a PICA-to-PICA bypass was selected following internal trapping. After anastomosis, the proximal PICA was occluded, whereas the small perforating artery was preserved. The next day, internal trapping of the right VA was performed. The patient's postoperative course was uneventful, except for mild dysphagia. Head magnetic resonance imaging revealed a small infarction on the right medulla. Three-dimensional computed tomography angiography revealed perfect PICA-to-PICA bypass patency. The patient was subsequently transferred to a rehabilitation hospital. The patient had no neurological symptoms at the six-month follow-up (Modified Rankin Score = 0). The preoperative feasibility of direct clipping of complex PICA aneurysms while preserving PICA is unpredictable. Various bypass methods, including the PICA-to-PICA bypass, are potential treatment options for complicated VA-PICA aneurysms.

Microsurgical anatomical vascular study of the PICA-PICA bypass

OBJECTIVE

To assess the posterior inferior cerebellar artery (PICA)-PICA bypass possibility.

METHODS

Fifteen adult cadaver heads were used for surgical simulation, and the far-lateral approach was used to expose the surgical field. The bilateral PICA course, diameter, and perforators were observed and measured to evaluate the possibility of a PICA-PICA bypass.

RESULTS

The PICA-PICA bypass was performed in seven (46.7 %) of the 15 specimens; the procedure was performed easily in three specimens, a little difficult in two, and was difficult in two specimens because of the relationship between the tonsil and the short parallel length of the bilateral tonsillomedullary (p3) segment. In eight (53.3 %) of the 15 specimens, PICA-PICA bypass was not feasible for reasons including 1) the caliber of the bilateral p3 was unmatched for bypass, 2) the distance of bilateral p3 in the midline was > 7 mm, 3) the middle segment of p3 perforating direct arteries limited the buffer length, and 4) single caudal loops.

CONCLUSION

The possibility of PICA-PICA bypass was determined by the proximity of the bilateral p3, caliber match, and mobilization of the bilateral caudal loop due to the perforators. The difficulty of the PICA-PICA bypass mainly depends on the relationship between the cerebellar tonsil and the parallel length of the bilateral PICA in the midline.

A Case of Proximal Posterior Inferior Cerebellar Artery (PICA) Aneurysm Treated with PICA-to-PICA Bypass and Trapping Surgery: Comparison with Occipital Artery-PICA Bypass

Posterior inferior cerebellar artery (PICA) aneurysms often require cerebral vascular reconstruction for surgical treatment because of their characteristic morphology. Despite its potential complications, the occipital artery-to-posterior inferior cerebellar artery (OA-PICA) bypass is a typical treatment because of its versatility. Although a few cases of intracranial-to-intracranial bypass have been reported, this type of vascular reconstruction is only regarded as an alternative to the OA-PICA bypass because of the uncertainty of bypass feasibility and potential risk of ischemic complications. In this article, we report a case of proximal PICA ruptured aneurysm that was treated with a PICA-to-PICA (PICA-PICA) bypass. A 79-year-old man presented with a chief complaint of sudden, severe headache and disturbances in consciousness. Radiological examination revealed a right proximal PICA fusiform aneurysm. The patient had many systemic disorders such as microscopic polyangiitis and steroid-induced diabetes mellitus that could have caused wound dehiscence and cerebrospinal fluid (CSF) leakage. We performed the PICA-PICA bypass and trapping surgery rather than the OA-PICA bypass to avoid skin problems and CSF leakage. The postoperative course was uneventful, and the patient was discharged on day 64 without any neurological disorders. In comparison with the OA-PICA bypass, the PICA-PICA bypass is less likely to cause CSF leakage and skin complications, although it carries the risk of specific ischemic complications and requires advanced surgical techniques. For some patients with systemic disorders, the PICA-PICA bypass could be an optimal treatment option for proximal fusiform PICA aneurysms rather than as an alternative to the OA-PICA bypass.

Tailored Communicating Bypass for the Management of Complex Anterior Communicating Artery Aneurysms: "Flow-Counteraction" In Situ Bypass and Interposition Bypass Using Contralateral A2 Orifice as Donor Site

BACKGROUND

The use of bypass surgery for anterior communicating artery (ACOM) aneurysms is technically challenging. Communicating bypass (COMB), such as pericallosal artery side-to-side anastomosis, is the most frequently used and anatomically directed reconstruction option. However, in many complex cases, this technique may not afford a sufficient blood supply or necessitate sacrificing the ACOM and the eloquent perforators arising from it.

OBJECTIVE

To evaluate tailored COMB and propose a practical algorithm for the management of complex ACOM aneurysms.

METHODS

For 1 patient with an aneurysm incorporating the entire ACOM, conventional in Situ A3-A3 bypass was performed as the sole treatment in order to create competing flow for aneurysm obliteration, sparing the sacrifice of eloquent perforators. In situations in which A2s were asymmetric in the other case, the contralateral A2 orifice was selected as the donor site to provide adequate blood flow by employing a short segment of the interposition graft.

RESULTS

The aneurysm was not visualized in patients with in Situ A3-A3 bypass because of the "flow-counteraction" strategy. The second patient, who underwent implementation of the contralateral A2 orifice for ipsilateral A3 interposition bypass, demonstrated sufficient bypass patency and complete obliteration of the aneurysm.

CONCLUSION

The feasibility of conventional COMB combined with complete trapping may only be constrained to selected ideal cases for the treatment of complex ACOM aneurysms. Innovative modifications should be designed in order to create individualized strategies for each patient because of the complexity of hemodynamics and the vascular architecture. Flow-counteraction in Situ bypass and interposition bypass using the contralateral A2 orifice as the donor site are 2 novel modalities for optimizing the advantages and broadening the applications of COMB for the treatment of complex ACOM aneurysms.

The evolution of intracranial aneurysm treatment techniques and future directions

Treatment techniques and management guidelines for intracranial aneurysms (IAs) have been continually developing and this rapid development has altered treatment decision-making for clinicians. IAs are treated in one of two ways: surgical treatments such as microsurgical clipping with or without bypass techniques, and endovascular methods such as coiling, balloon- or stent-assisted coiling, or intravascular flow diversion and intrasaccular flow disruption. In certain cases, a single approach may be inadequate in completely resolving the IA and successful treatment requires a combination of microsurgical and endovascular techniques, such as in complex aneurysms. The treatment option should be considered based on factors such as age; past medical history; comorbidities; patient preference; aneurysm characteristics such as location, morphology, and size; and finally the operator’s experience. The purpose of this review is to provide practicing neurosurgeons with a summary of the techniques available, and to aid decision-making by highlighting ideal or less ideal cases for a given technique. Next, we illustrate the evolution of techniques to overcome the shortfalls of preceding techniques. At the outset, we emphasize that this decision-making process is dynamic and will be directed by current best scientific evidence, and future technological advances.

Treatment of a giant complicated distal posterior inferior cerebellar artery aneurysm: A case report and literature review

Giant intracranial aneurysms, especially giant aneurysms of the distal posterior inferior cerebellar artery (PICA), remain the most difficult and challenging cerebrovascular lesions for neurosurgeons to treat. The morbidity and mortality rates of microsurgical clipping are relatively high, and endovascular embolization is also associated with many complications. In the present report, the case of a 46-year-old female patient who presented with headache and dizziness for 3 years, which was aggravated and combined with limb weakness for 1 day, is presented. A CT scan showed a lesion occupying the fourth ventricle, with slight bleeding. A MR scan also revealed a lesion occupying the fourth ventricle and compressing the brainstem, and there was distortion of the cisterns around the brainstem. CT angiography examination showed a giant irregular aneurysm located in the PICA. After evaluation, the PICA aneurysm was removed, and the PICA was clipped via a microsurgical technique without ischemia or neurological sequelae. Long-term follow-up demonstrated that the symptoms of headache and dizziness disappeared without relapse. Based on a review of the literature, this method may represent an alternative strategy for the treatment of giant PICA aneurysms, especially for aneurysms not suitable for direct clipping or endovascular embolization.

[Successful combination treatment of giant bicameral fusiform partially thrombosed vertebral artery aneurysm at 12-year-old patient (practical case and literature review)]

Giant cerebral aneurysms are diagnosed more often in children than in adults. Treatment of giant aneurysms is carried out both by endovascular and microsurgical methods. Literature information on combination of microsurgical and endovascular operations of cerebral aneurysms at children is little. A clinical case of the combined treatment of a giant bicameral fusiform partially thrombosed aneurysm of the right vertebral artery at a 12-year-old patient and a literature review on this topic are presented. The patient underwent several complex neurosurgical interventions during two operations: 1) microsurgery including revascularization of the right posterior lower cerebellar artery, thrombectomy and trapping of the larger chamber of fusiform aneurysm of the right vertebral artery, and 2) endovascular, which consists in the installation of redirecting stent from the left vertebral artery to main artery. The uniqueness of the case which we presented lies in the fact that the tactics of stage combined treatment for a complex aneurysm at child was originally planned and successfully implemented. The treatment allowed to ensure a complete shutdown of aneurysm and to exclude postoperative cerebral complications.

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.

Occipital Artery to Extradural Vertebral Artery Bypass for Posterior Circulation Ischemia

BACKGROUND

Posterior circulation ischemic strokes can have devastating consequences, despite medical therapies. Extracranial–intracranial bypass for the augmentation of flow is a treatment option for selected patients with hemodynamic compromise and recurrent ischemia. However, posterior circulation bypass carries a higher risk and lower patency rate than bypass with anterior circulation.

OBJECTIVE

To present the occipital artery to the extradural vertebral artery (OA-eVA) bypass for posterior circulation ischemia.

METHODS

We retrospectively reviewed our experience of the OA-eVA bypass surgery in the treatment of bilateral vertebral steno-occlusive disease.

RESULTS

Seventeen patients were identified. Thirteen patients had bilateral vertebral artery (VA) occlusion (type I), while 4 patients had VA occlusion with contralateral VA severe stenosis (type II). All patients had cerebellar or pons infarction, for which the postoperative bypass patency rate was 100%, with carotid angiogram demonstrating excellent filling of the rostral basilar system or the posterior inferior cerebellar artery territory. The long-term follow-up outcome was favorable (modified Rankin score of 0-2) in 82% of patients (7 patients had complete resolution and 7 had improvement of symptoms) and unfavorable in 18%. One type II case without previous endovascular therapy developed recurrent ischemic onset associated with bypass occlusion.

CONCLUSION

OA-eVA bypass is a minimally invasive and effective alternative to posterior circulation ischemia. It provides sufficient blood flow augmentation to the vertebrobasilar territory. The advantages of this novel therapeutic strategy include avoiding performing craniotomy and deep bypass and achieving shorter operative times compared to conventional bypass surgery.

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.

Variations of Occipital Artery-Posterior Inferior Cerebellar Artery Bypass: Anatomic Consideration

BACKGROUND

Advances in diagnosis of posterior inferior cerebellar artery (PICA) aneurysms have revealed the high frequency of distal and/or dissecting PICA aneurysms. Surgical treatment of such aneurysms often requires revascularization of the PICA including but not limited to its caudal loop.

OBJECTIVE

To examine the microsurgical anatomy involved in occipital artery (OA)-PICA anastomosis at various anatomic segments of the PICA.

METHODS

Twenty-eight PICAs in 15 cadaveric heads were examined with the operating microscope to take morphometric measurements and explore the specific anatomy of bypass procedures.

RESULTS

OA bypass to the p2, p3, p4, or p5 segment was feasible with a recipient vessel of sufficient diameter. The loop wandering near the jugular foramen in the p2 segment provided sufficient length without requiring cauterization of any perforating arteries to the brainstem. Wide dissection of the cerebellomedullary fissure provided sufficient exposure for the examination of some p3 segments and all p4 segments hidden by the tonsil. OA-p5 bypass was placed at the main trunk before the bifurcation in 5 hemispheres and at the larger hemispheric trunk in others.

CONCLUSION

Understanding the possible variations of OA-PICA bypass may enable revascularization of the appropriate portion of the PICA when the parent artery must be occluded. A detailed anatomic understanding of each segment clarifies important technical nuances for the bypass on each segment. Dissection of the cerebellomedullary fissure helps to achieve sufficient exposure for the bypass procedures on most of the segments.

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.

[Giant partially thrombosed aneurysm of the vertebral artery: a case report and literature review]

INTRODUCTION

Giant partially thrombosed aneurysms of the vertebral artery are recalcitrant to treatment by microsurgical trapping and thrombectomy. Application of endovascular interventions is limited due to substantial brainstem compression and cranial nerve neuropathy. Combined endovascular exclusion and microsurgical excision provides an approach to treatment of these lesions.

CLINICAL CASE

A 48-year-old female patient presented with progressive complaints of ataxia, diplopia in left lateral gaze, and dysphagia. Imaging studies (CT, MRI, angiography) revealed a giant partially thrombosed aneurysm of the right vertebral artery and pronounced brainstem compression.

TREATMENT

The initial phase of treatment involved endovascular occlusion of the vertebral artery and aneurysm trapping that did not lead to changes in the postoperative patient's neurological status. MRI demonstrated complete aneurysm thrombosis and a weak TOF signal in the vertebral artery near the proximal aneurysm neck region. Because of persistent brainstem compression, the patient underwent right suboccipital craniectomy and hemilaminectomy of the CI arch for aneurysm excision one week after endovascular occlusion. After isolating the aneurysmal sac, the vertebral artery was transected, and two small branches extending from the aneurysm neck to the brainstem were also coagulated and transected, followed by aneurysm excision. Numerous vasa vasorum in the wall of the proximal vertebral artery and aneurysm neck were coagulated to stop bleeding. After surgery, the patient developed neurological symptoms (right leg ataxia and dysphagia worsening) due to lateral medullary infarction (confirmed by MRI) that presumably resulted from coagulation of two small perforating branches coming from the aneurysm neck to the brainstem. Recovery of the patient's neurological functions was observed during conservative treatment. The patient was discharged with mild right leg ataxia and preoperative left-sided abducens paresis.

CONCLUSION

Medulla oblongata compression associated with a giant thrombosed aneurysm of the vertebral artery can be eliminated by endovascular trapping followed by surgical excision of the aneurysm. Preserving the vasa vasorum feeding the brainstem is crucial for prevention of ischemic complications.

Stent-assisted Coiling for Ruptured Basilar Artery Dissecting Aneurysms: An Initial Experience of Four Cases

No treatment strategy has been established for subarachnoid hemorrhages due to basilar artery (BA) trunk dissecting aneurysms. Our aim was to report our initial experience performing stent-assisted coiling (SAC) for ruptured BA dissecting aneurysms to validate the effectiveness of this treatment. We experienced four consecutive cases of ruptured dissecting BA trunk aneurysm treated with SAC between 2008 and 2014 at three institutions. Aneurysm rebleeding was prevented without causing severe brainstem ischemia in all cases. In our opinion, both the blockage of the inflow to aneurysms and the preservation of the antegrade flow of the BA can be achieved by SAC, although controversies regarding long-term stability and appropriate antiplatelet therapy remain.

In Situ Intersegmental Anastomosis within a Single Artery for Treatment of an Aneurysm at the Posterior Inferior Cerebellar Artery: Closing Omega Bypass

A 74-year-old patient was diagnosed with a subarachnoid hemorrhage suspected from a dissecting aneurysm located at the lateral medullary segment of the posterior inferior cerebellar artery (PICA). Because perforators to the medulla arose both proximal and distal to the dissecting segment, revascularization for distal flow was essential. However, several previously reported methods for anastomosis, such as an occipital artery-PICA bypass or resection with PICA end-to-end anastomosis could not be used. Ultimately, we performed an in situ side-to-side anastomosis of the proximal loop of the PICA with distal caudal loops within a single artery, as a "closing omega," followed by trapping of the dissected segment. The aneurysm was obliterated successfully, with intact patency of the revascularized PICA.

Intracranial-to-intracranial bypass for posterior inferior cerebellar artery aneurysms: options, technical challenges, and results in 35 patients

OBJECT Intracranial-to-intracranial (IC-IC) bypasses are alternatives to traditional extracranial-to-intracranial (EC-IC) bypasses to reanastomose parent arteries, reimplant efferent branches, revascularize branches with in situ donor arteries, and reconstruct bifurcations with interposition grafts that are entirely intracranial. These bypasses represent an evolution in bypass surgery from using scalp arteries and remote donor sites toward a more local and reconstructive approach. IC-IC bypass can be utilized preferentially when revascularization is needed in the management of complex aneurysms. Experiences using IC-IC bypass, as applied to posterior inferior cerebellar artery (PICA) aneurysms in 35 patients, were reviewed. METHODS Patients with PICA aneurysms and vertebral artery (VA) aneurysms involving the PICA's origin were identified from a prospectively maintained database of the Vascular Neurosurgery Service, and patients who underwent bypass procedures for PICA revascularization were included. RESULTS During a 17-year period in which 129 PICA aneurysms in 125 patients were treated microsurgically, 35 IC-IC bypasses were performed as part of PICA aneurysm management, including in situ p3-p3 PICA-PICA bypass in 11 patients (31%), PICA reimplantation in 9 patients (26%), reanastomosis in 14 patients (40%), and 1 V3 VA-to-PICA bypass with an interposition graft (3%). All aneurysms were completely or nearly completely obliterated, 94% of bypasses were patent, 77% of patients were improved or unchanged after treatment, and good outcomes (modified Rankin Scale ≤ 2) were observed in 76% of patients. Two patients died expectantly. Ischemic complications were limited to 2 patients in whom the bypasses occluded, and permanent lower cranial nerve morbidity was limited to 3 patients and did not compromise independent function in any of the patients. CONCLUSIONS PICA aneurysms receive the application of IC-IC bypass better than any other aneurysm, with nearly one-quarter of all PICA aneurysms treated microsurgically at our center requiring bypass without a single EC-IC bypass. The selection of PICA bypass is almost algorithmic: trapped aneurysms at the PICA origin or p1 segment are revascularized with a PICA-PICA bypass, with PICA reimplantation as an alternative; trapped p2 segment aneurysms are reanastomosed, bypassed in situ, or reimplanted; distal p3 segment aneurysms are reanastomosed or revascularized with a PICA-PICA bypass; and aneurysms of the p4 segment that are too distal for PICA-PICA bypass are reanastomosed. Interposition grafts are reserved for when these 3 primary options are unsuitable. A constructive approach that preserves the PICA with direct clipping or replaces flow with a bypass when sacrificed should remain an alternative to deconstructive PICA occlusion and endovascular coiling when complete aneurysm occlusion is unlikely.

Tailored PICA Revascularization for Unusual Ruptured Fusiform Vertebro-PICA Origin Aneurysms: Rationale and Case Illustrations

Ruptured fusiform aneurysms of the vertebral artery involving posterior inferior cerebellar artery (PICA) origin are difficult to manage without sacrificing PICA. In this report, two very unusual cases are described which highlight different revascularization strategies that may be required. The first case initially appeared to be a small saccular PICA origin aneurysm, but detailed angiography showed a serpentine recanalization of a fusiform aneurysm. This was treated with PICA-PICA anastomosis and trapping of the aneurysm. The second case is a dissecting vertebral aneurysm with both PICA and the anterior spinal artery originating from the dome. PICA was found to be a bihemispheric variant, so no in situ bypass was available, and an occipital artery to PICA bypass was performed. The vertebral artery was occluded proximally only and follow-up angiography showed remodeling of the distal vertebral artery with the anterior spinal artery filling by retrograde flow from the distal vertebral artery. These cases illustrate both the anatomic variability of this region as well as the need to be familiar with multiple treatment strategies including revascularization techniques to be able to successfully treat these aneurysms.

Management of hemorrhagic dissecting vertebral artery aneurysms involving posterior inferior artery

We reported 2 cases with hemorrhagic dissecting vertebral artery (VA) aneurysms involving posterior inferior cerebellar artery (PICA), and one was treated with aneurysm trapping and PICA-VA anastomosis, whereas another was treated with coil embolization and VA-to-PICA stent placement. We suggest both bypass surgery and VA-to-PICA stent placement are good options for PICA revascularization.

Radial Artery Bypass for Intractable Vertebrobasilar Insufficiency: Case Series and Review of the Literature

BACKGROUND

Vertebrobasilar insufficiency resulting from embolism, atherosclerosis, or arterial dissection has long been a challenge for successful management and outcomes. The main treatment options include medical therapy, angioplasty and stenting, and surgical revascularization. Unlike cardiac or peripheral vascular revascularization, large randomized trials with cerebrorevascularization have not revealed favorable outcomes. In patients who have failed maximal medical therapy, and having persistent debilitating symptomology, cerebral revascularization may still be a viable option.

METHODS

We report 3 patients who presented with symptoms of vertebrobasilar ischemia. The diagnosis was verified by computerized tomographic arteriography and digital subtraction angiography.

RESULTS

These patients subsequently underwent revascularization with a radial artery graft. We also present a comprehensive review of the literature of treatment for vertebrobasilar insufficiency.

CONCLUSIONS

Surgical revascularization should be considered in the posterior circulation in the rare subset of patients with VBI, who remain symptomatic despite having a protracted course of maximal medical therapy with large- and medium-sized vessel occlusions and poor collateral circulation.

Revascularization and Aneurysm Surgery

BACKGROUND:

Given advances in endovascular technique, the indications for revascularization in aneurysm surgery have declined.

OBJECTIVE:

We sought to define indications, outline technical strategies, and evaluate the outcomes of patients treated with bypass in the endovascular era.

METHODS:

We retrospectively reviewed all aneurysms treated between September 2006 and February 2013.

RESULTS:

We identified 54 consecutive patients (16 males and 39 females) with 56 aneurysms. Aneurysms were located along the cervical internal carotid artery (ICA) (n = 1), petrous/cavernous ICA (n = 1), cavernous ICA (n = 16), supraclinoid ICA (n = 7), posterior communicating artery (n = 2), anterior cerebral artery (n = 4), middle cerebral artery (MCA) (n = 13), posterior cerebral artery (PCA) (n = 3), posterior inferior cerebellar artery (n = 4), and vertebrobasilar arteries (n = 5). Revascularization was performed with superficial temporal artery (STA) to MCA bypass (n = 25), STA to superior cerebellar artery (SCA) (n = 3), STA to PCA (n = 1), STA-SCA/STA-PCA (n = 1), occipital artery (OA) to PCA (n = 2), external carotid artery/ICA to MCA (n = 15), OA to MCA (n = 1), OA to posterior inferior cerebellar artery (n = 1), and in situ bypasses (n = 8). At a mean clinical follow-up of 18.5 months, 45 patients (81.8%) had a good outcome (Glasgow Outcome Scale 4 or 5). There were 7 cases of mortality (12.7%) and an additional 9 cases of morbidity (15.8%). At a mean angiographic follow-up of 17.8 months, 14 bypasses were occluded. Excluding the 7 cases of mortality, the majority of aneurysms (n = 42) were obliterated. We identified 7 cases of residual aneurysm and recurrence in 6 patients at follow-up.

CONCLUSION:

Given current limitations with existing treatments, cerebral revascularization remains an essential technique for aneurysm surgery.

How I do it: side to side posterior inferior cerebellar artery – posterior inferior cerebellar artery bypass procedure

BACKGROUND

An intracranial in situ side to side posterior circulation procedure is performed infrequently. The scope of treatment modalities of vertebral artery-PICA aneurysms and vertebral dissections is limited due to the lack of many representations of this procedure's technical nuances.

METHODS

To demonstrate the technical nuances of a PICA-PICA side to side bypass in a 50-year-old woman with a dissecting vertebral-PICA junction pseudoaneurysm.

CONCLUSION

Details of the pre-operative evaluation, decision process and operative nuances of side to side PICA-PICA bypass are described. Indications and limitations are emphasized. Vascular neurosurgeons should consider this elegant procedure in their treatment armamentarium.

Endovascular coil trapping of a ruptured dissecting aneurysm of the vertebral artery using detachable coils and micro-tornado® coils

We experienced a patient with a ruptured dissecting aneurysm of the vertebral artery who was treated by trapping of the lesion using Guglielmi detachable coils (GDCs) with micro-tornado® coils (MTCs). An 80-year-old male was transferred with a ruptured left vertebral artery dissecting aneurysm (VADA). The dissected portion of the vertebral artery was effectively trapped using GDCs and MTCs. The MTCs used for neurointervention were comprised of various types of coils and we successfully placed them into the parent artery of the dissected segment. The author suggests that this case demonstrates the usefulness of endovascular coil trapping of VADAs using MTCs in achievement of embolization.

Endovascular treatment of proximal and distal posterior inferior cerebellar artery aneurysms

Object

Surgical clipping of posterior inferior cerebellar artery (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. The authors assess the feasibility, safety, and efficacy of endovascular therapy in the largest series of proximal and distal PICA aneurysms to date.

Methods

A total of 76 patients, 54 with proximal and 22 with distal PICA aneurysms, underwent endovascular treatment at Jefferson Hospital for Neuroscience between 2001 and 2011.

Results

Endovascular treatment was successful in 52 patients (96.3%) with proximal aneurysms and 19 patients (86.4%) with distal aneurysms. Treatment consisted of selective aneurysm coiling in 60 patients (84.5%) (including 4 with stent assistance and 4 with balloon assistance) and parent vessel trapping in 11 patients (15.5%). Specifically, a deconstructive procedure was necessary in 9.6% of proximal aneurysms (5 of 52) and 31.6% of distal aneurysms (6 of 19). There were 9 overall procedural complications (12.7%), 6 infarcts (8.5%; 4 occurring after deliberate occlusion of the PICA), and 3 intraprocedural ruptures (4.2%). The rate of procedure-related permanent morbidity was 2.8%. Complete aneurysm occlusion was achieved in 63.4% of patients (45 of 71). One patient (1.4%) treated with selective aneurysm coiling suffered a rehemorrhage on postoperative Day 15. The mean angiographic follow-up time was 17.2 months. Recurrence and re-treatment rates were, respectively, 20% and 17.1% for proximal aneurysms compared with 30.8% and 23.1% for distal aneurysms. Favorable outcomes (moderate, mild, or no disability) at follow-up were seen in 93% of patients with unruptured aneurysms and in 78.7% of those with ruptured aneurysms.

Conclusions

Endovascular therapy is a feasible, safe, and effective treatment in patients with proximal and distal PICA aneurysms, providing excellent patient outcomes and adequate protection against rehemorrhage. The long-term incidence of aneurysm recanalization appears to be high, especially in distal aneurysms, and requires careful angiographic follow-up.

Long-term outcome of endovascular reconstruction with the Pipeline embolization device in the management of unruptured dissecting aneurysms of the intracranial vertebral artery

Object

Use of a flow-diverting device has shown promising short-term results in the management of vertebral artery (VA) dissecting aneurysms, but there is still uncertainty regarding its long-term efficacy and safety. The authors report their initial experience with respect to the potential utility and long-term clinical outcomes of using a flow-diverting device in the treatment of unruptured dissecting VA aneurysms.

Methods

The authors conducted a retrospective review of all cases of unruptured intracranial VA dissecting aneurysms treated at their institution (Tuen Mun Hospital) with a flow-diverting device. They describe the clinical presentations and angiographic features of the cases and report the clinical outcome (with modified Rankin Scale [mRS] scores) at most recent follow-up, as well as results of the latest angiographic assessment, with particular focus on in-stent patency and side-branch occlusion.

Results

A total of 4 aneurysms were successfully obliterated by using flow-diverting devices alone. Two devices were deployed in a telescoping fashion in each of 2 aneurysms, whereas only 1 device was inserted in each of the other 2 aneurysms. No periprocedural complication was encountered. No patient showed any angiographic evidence of recurrence, in-stent thrombosis, or side-branch occlusion in angiographic reassessment at a mean of 22 months after treatment (range 18–24 months). As of the most recent clinical follow-up (mean 30 months after treatment, range 24–37 months), all patients had favorable outcomes (mRS Score 0).

Conclusions

Reconstruction using a flow-diverting device is an attractive alternative in definitive treatment of dissecting VA aneurysms, demonstrating favorable long-term clinical and angiographic outcomes and the ability to maintain parent artery and side-branch patency. It is particularly useful in cases with eloquent side-branch or dominant VA involvement.

Stenting from the vertebral artery to the posterior inferior cerebellar artery

BACKGROUND AND PURPOSE

There are only a few reports on the feasibility and safety of stents used in the PICA, and clinical and angiographic follow-up results have not been fully addressed. We report our experiences of treating PICA origin or vertebral artery-PICA lesions by using self-expanding stents as adjuvant or rescue therapy with angiographic and clinical follow-up results.

MATERIALS AND METHODS

Six patients were treated with self-expanding stent placements from the vertebral artery to the PICA. Two patients had a vertebral artery dissecting aneurysm involving the PICA origin, 3 had vertebral artery-PICA aneurysms, and 1 had segmental stenosis of the vertebral artery harboring the origin of the PICA. The safety, feasibility, and follow-up angiographic results were retrospectively evaluated.

RESULTS

All procedures were successfully performed without any procedure-related complications. None of the patients showed PICA territorial infarction on DWI posttreatment. All patients were neurologically intact during the clinical follow-up of 3-24 months following the procedure. Follow-up angiography was performed at between 6 and 12 months in 5 of the 6 patients and was scheduled for the sixth patient but was not performed. The PICA showed good patency without in-stent stenosis in all 5 patients.

CONCLUSIONS

In patients with lesions of the PICA origin or vertebral artery-PICA lesions, vertebral artery-to-PICA stent placement may be an option for preserving PICA patency in selected cases.

Vertebral artery dissecting aneurysm treated by proximal occlusion and posterior inferior cerebellar artery reconstruction with fenestrated clips. Case report

A 57-year-old man presented with subarachnoid hemorrhage caused by a dissecting aneurysm of the vertebral artery close to the origin of the posterior inferior cerebellar artery (PICA). The aneurysm was treated successfully with two fenestrated clips preserving the efferent artery with anterograde blood flow without PICA anastomosis. The postoperative course was uneventful. Postoperative angiography indicated disappearance of the aneurysm and anterograde blood flow of the PICA.

Operative nuances of side-to-side in situ posterior inferior cerebellar artery-posterior inferior cerebellar artery bypass procedure

BACKGROUND

An intracranial posterior circulation revascularization procedure in the form of a side-to-side in situ posterior inferior cerebellar artery (PICA)-PICA bypass operation was introduced in 1991. This elegant and apparently low-risk operation is performed infrequently. Thus, the operative nuances used in this procedure have not been well reported, limiting the scope of treatment modalities of vertebral artery-PICA aneurysms and vertebral dissections.

OBJECTIVE

To repair an incidental right-sided PICA aneurysm noted in a 51-year-old woman in magnetic resonance imaging and subsequent angiography.

METHODS

The patient underwent side-to-side in situ PICA-PICA bypass surgery.

RESULTS

Immediate indocyanine green angiography suggested that the PICA distal to the aneurysms was filling in a retrograde fashion through the bypass. On the following day, the patient was taken for coil embolization of the aneurysm. However, angiography images revealed that the aneurysm was spontaneously thrombosed, the proximal PICA was patent, and the PICA distal to the aneurysms was filling in a retrograde fashion, as suspected in intraoperative indocyanine green angiography. No further treatments were done. The patient recovered fully.

CONCLUSION

We describe in detail the preoperative evaluation, decision process, and operative techniques for a side-to-side in situ PICA-PICA bypass operation, which is a relatively safe and elegant posterior circulation bypass procedure.

Intracranial in situ side-to-side microvascular anastomosis: principles, operative technique, and applications

OBJECTIVE

Side-to-Side microvascular anastomosis is a revascularization technique used to create an artificial conduit between two similar adjacent vessels. This technique is used for microsurgical clipping of aneurysms, when indicated. It is important to study the angiographic results, both immediate and long term, along with the clinical outcomes and indications of the procedure.

METHODS

Fifteen patients who had this procedure over a fourteen-year period were reviewed for patency of bypass by intra-arterial digital subtraction angiography (DSA) and computed tomographic arteriograms (CTA) and their clinical outcomes were studied. The mean age of the study group was 53.4 years and mean angiographic follow up period was 14 months.

RESULTS

All surviving patients (14 patients) had patent anastomosis with good clinical outcomes. None of the patients developed a clinically manifested stroke due to the procedure, while one had a small asymptomatic infarct detected post operatively.

CONCLUSION

This technique is a useful and durable solution for correcting critical stenosis or complete occlusion of the vessels, while clipping intracranial aneurysms.

Detachable coil embolization for saccular posterior inferior cerebellar artery aneurysms

OBJECTIVE

Surgical treatment of posterior inferior cerebellar artery (PICA) aneurysms is challenging due to limited surgical accessibility. Endovascular approach has a benefit of avoiding direct injury to the brainstem or lower cranial nerves. Therefore, it has recently been considered an alternative or primary modality for PICA aneurysms. We retrospectively assessed outcomes following detachable coil embolization of saccular PICA aneurysms.

METHODS

From February 1997 to December 2007, we performed endovascular procedures to treat 15 patients with 15 PICA aneurysms. Fourteen patients with 14 PICA aneurysms morphology of which was saccular were reviewed retrospectively. Twelve patients had ruptured aneurysms. The aneurysms arose from the PICA origin site (n = 12), the PICA lateral medullary segment (n = 1), or the PICA tonsilomedullary segment (n = 1).

RESULTS

Complete aneurysm occlusion was achieved in 10 patients, residual neck in 3, and residual sac in one. Radiological follow-up was performed in 7 patients with mean duration of 34.7 months (range, 1-97 months) and showed stable or complete occlusion in 6 patients. There were no rebleeding or retreatment after endovascular treatment. Thromboembolism was the only procedure-related complication (n = 4 ; 28.6%). Asymptomatic PICA infarction occurred in two patients and symptomatic PICA infarction in two elderly patients with poor clinical grade. Of these procedural PICA infarction cases, 1 symptomatic PICA infarction patient developed ventriculitis and septic shock leading to death. The clinical outcome was good in 10 patients (71.4%).

CONCLUSIONS

In the present study, detachable coil embolization has shown as an efficient modality for PICA saccular aneurysms challenging indications of microsurgery. However, thromboembolic complications should be considered, especially in poor clinical elderly patients with ruptured aneurysms.

POSTERIOR INFERIOR CEREBELLAR ARTERY ORIGIN THROMBOSIS WITH ANEURYSM OF COLLATERALIZED POSTERIOR MENINGEAL ARTERY PRESENTING AS SUBARACHNOID HEMORRHAGE

OBJECTIVE

This is the first report of a ruptured aneurysm involving a collateral branch to the posterior inferior cerebellar artery (PICA) in a patient who had a subarachnoid hemorrhage.

CLINICAL PRESENTATION

A 56-year-old man initially presented with a subarachnoid hemorrhage and underwent 2 catheter-based 4-vessel angiograms with negative results. A delayed angiogram 4 weeks later revealed a dissecting aneurysm of the posterior meningeal artery, a branch of the vertebral artery.

INTERVENTION

A 3-dimensional reconstruction of the vertebral angiogram showed proximal occlusion of the proximal left PICA and distal filling via a collateral branch from the posterior meningeal artery. A far-lateral approach was used for this patient. The aneurysm was found along the course of the collateral posterior meningeal artery and was clipped successfully.

CONCLUSION

Aneurysms involving collateral branches of the PICA are rare. It is important to recognize such collateral flow preoperatively because inadvertent sacrifice of these vessels during a surgical approach could lead to stroke and neurological deficits of the PICA territory.

BYPASS SURGERY FOR COMPLEX BRAIN ANEURYSMS

OBJECTIVE

Bypass surgery for brain aneurysms is evolving from extracranial-intracranial (EC-IC) to intracranial-intracranial (IC-IC) bypasses that reanastomose parent arteries, revascularize efferent branches with in situ donor arteries or reimplantation, and reconstruct bifurcated anatomy with grafts that are entirely intracranial. We compared results with these newer IC-IC bypasses to conventional EC-IC bypasses.

METHODS

During a 10-year period, 82 patients underwent bypass surgery as part of their aneurysm management. A quarter of the patients presented with ruptured aneurysms and two-thirds presented with compressive symptoms from unruptured aneurysms. Most aneurysms (82%) had non-saccular morphology and 56% were giant sized. Common locations included the cavernous internal carotid artery (23%), middle cerebral artery (20%), and posteroinferior cerebellar artery (12%).

RESULTS

Forty-seven patients (57%) received EC-IC bypasses and 35 patients (43%) received IC-IC bypasses, including 9 in situ bypasses, 6 reimplantations, 11 reanastomoses, and 9 intracranial grafts. Aneurysm obliteration rates were comparable in EC-IC and IC-IC bypass groups (97.9% and 97.1%, respectively), as were bypass patency rates (94% and 89%, respectively). Three patients died (surgical mortality, 3.7%), and 4 patients were permanently worse as a result of bypass occlusions (neurological morbidity, 4.9%). At late follow-up (mean duration, 41 months), good outcomes (Glasgow Outcome Scale score 5 or 4) were measured in 68 patients (90%) overall, and were similar in EC-IC and IC-IC bypass groups (91% and 89%, respectively). Changes in Glasgow Outcome Scale score were slightly more favorable with IC-IC bypass (6% worse or dead after IC-IC bypass versus 14% with EC-IC bypass).

CONCLUSION

IC-IC bypasses compare favorably to EC-IC bypasses in terms of aneurysm obliteration rates, bypass patency rates, and neurological outcomes. IC-IC bypasses can be more technically challenging to perform, but they do not require harvest of extracranial donor arteries, spare patients a neck incision, shorten interposition grafts, are protected inside the cranium, use caliber-matched donor and recipient arteries, and are not associated with ischemic complications during temporary arterial occlusions. IC-IC bypass can replace conventional EC-IC bypass with more anatomic reconstructions for selected aneurysms involving the middle cerebral artery, posteroinferior cerebellar artery, anterior cerebral artery, and basilar apex.

In Situ Rescue Bypass for Iatrogenic Avulsion of Parent Artery during Clipping Large Pericallosal Artery Aneurysm

A case of large aneurysm arising from the distal end of an azygous A2 segment is presented. Multiple clip application inadvertently tore the aneurysmal neck, resulting in near avulsion of a right pericallosal artery origin. After an unsuccessful attempt to repair the avulsion, it was treated by occlusion of the origin of the pericallosal artery and an A4-A4 anterior cerebral artery in situ bypass without neurological deficits. The surgical technique and previous reports on side-to-side in situ bypass are discussed.

Operative nuances of an occipital artery to posterior inferior cerebellar artery bypass

Occipital artery to posterior inferior cerebellar artery bypasses remain an important tool for cerebrovascular neurosurgeons, particularly in the management of complex aneurysms of the posterior inferior cerebellar artery requiring proximal occlusion or trapping. The procedure requires meticulous technique and attention to detail. The authors outline their technique for accomplishing this bypass emphasizing nuances for complication avoidance.

Treatment of a complex posterior fossa aneurysm in a child using side-to-side posterior inferior cerebellar artery-posterior inferior cerebellar artery bypass

Endovascular and cerebral bypass therapies are rarely used in children. The authors describe the treatment of a partially coiled giant distal vertebral artery (VA)-posterior inferior cerebellar artery (PICA) aneurysm in a child. They performed a side-to-side PICA-PICA anastomosis followed by endovascular VA aneurysm deconstruction with PICA preservation. A healthy 11-year-old boy developed progressive holocephalic headaches over the course of 2 months. Magnetic resonance imaging and magnetic resonance angiography revealed a large right PICA aneurysm causing brainstem compression. In November 2005, 2 Neuroform stents and Guglielmi detachable coils and Matrix were placed in the aneurysm at an outside institution. In 2006, angiography demonstrated aneurysm enlargement from which the PICA originated, coil compaction, and increased mass effect. The patient underwent a PICA-PICA bypass with intraoperative flow measurements followed by endovascular embolization of the aneurysm and parent VA. An angiogram obtained after the procedure demonstrated filling of the right PICA medullary branch through the bypass and obliteration of the aneurysm. The patient remained neurologically intact. Giant aneurysms of the posterior circulation are rare but do occur in children. With the aid of combined surgical and endovascular strategies the authors were able to safely eliminate the aneurysm from circulation with good outcome. Cerebral bypass and endovascular deconstructive therapies can be used safely in children but should be reserved for cases in which direct treatment carries significant risk. Careful surgical and endovascular planning with intraoperative flow assessment is essential for good outcome.

Emergency extra-intracranial bypass surgery in the treatment of cerebral aneurysms

The need of an emergency bypass in hazardous situations during treatment of intracranial aneurysms has rarely been addressed in the literature. We report our 10 year experience with emergency bypass for aneurysm treatment. We retrospectively analyzed the data of patients who underwent emergency bypass surgery for the treatment of an intracranial aneurysm and compared the results with patients treated with bypass as a planned procedure during the same time period. Three groups were formed: group I, emergency bypass during clipping procedure; group II, emergency bypass for therapy refractory vasospasm; group III, planned bypass surgery. Sixteen patients (35%) out of 46 were treated with emergency bypass. In group I (11 patients) mortality was 37% and a good outcome (GOS 4 & 5) was achieved in 36%. In group II (5 patients) mortality was 20% and good outcome was reached in 60%. In group III (30 patients) mortality was 10% and good outcome was achieved in 86.6%. Outcome was worse in patients with additional SAH. An emergency bypass procedure as part of the aneurysm treatment should be considered in risky situations. Accurate timely decision-making is crucial combined with a fast and secure bypass technique. Treatment of refractory vasospasm with emergency bypasses may help to improve outcome in selected patients.

Posterior inferior cerebellar artery aneurysms: incidence, clinical presentation, and outcome of endovascular treatment

BACKGROUND AND PURPOSE

Results of endovascular treatment of PICA aneurysms are not well established. The purpose of this study was to report incidence, clinical presentation, and outcome of endovascular treatment in 46 patients with 47 posterior inferior cerebellar artery (PICA) aneurysms.

MATERIALS AND METHODS

Of 2169 aneurysms treated between January 1995 and March 2007, 60 were located on the PICA (incidence, 2.8%). Forty-seven proximal PICA aneurysms in 46 patients were treated with endovascular techniques, 37 ruptured (79%) and 10 unruptured (21%). Four patients presented with lower cranial nerve palsies. Mean aneurysm size was 6.8 mm (median, 6 mm; range, 2-32 mm). Forty-three aneurysms were occluded with coils (6 including the PICA origin), and 4 were treated with proximal vertebral artery (VA) occlusion.

RESULTS

Four aneurysms treated with proximal VA occlusion were not occluded. Procedural rupture occurred in 9 aneurysms leading to death in 2 patients and to permanent disability in 1 patient. One patient developed lateral medullary and cerebellar infarctions after PICA occlusion. Combined mortality and morbidity was 8.6% (4 of 46). Outcome at 6 months in 38 surviving patients was good in 35 and moderate in 3. No hemorrhage occurred during 109 patient-years of follow-up. Symptoms of mass effect resolved in all 4 patients.

CONCLUSION

In our experience, PICA aneurysms were challenging lesions, prone to procedural rupture. In some instances, endovascular treatment required occlusion of the parent PICA; usually this was well tolerated. In other instances, treatment required occlusion of the VA. Although this was effective in alleviation of symptoms of mass effect, it was not effective in causing thrombosis of the aneurysm.

Endovascular treatment of symptomatic intradural vertebral dissecting aneurysms

BACKGROUND AND PURPOSE

The purpose of this study was to report our experience with endovascular treatment of 14 patients with symptomatic intradural vertebral dissecting aneurysms.

MATERIALS AND METHODS

Between January 2000 and January 2006, 14 patients with symptomatic intradural dissecting vertebral aneurysms were treated. A total of 756 (568 ruptured, 188 unruptured) endovascular treated aneurysms (incidence, 1.9%) were treated during this period. There were 7 female and 7 male patients with a mean age of 48 years (age range, 10-64 years). Thirteen patients (93%) presented with subarachnoid hemorrhage (SAH) and 1 (7%) presented with acute symptoms of mass effect on the brain stem.

RESULTS

Treatment consisted of coil occlusion of the dissected arterial segment including the aneurysm (internal coil trapping) in 13 of 14 patients and stent placement over the aneurysm as the only therapy in 1 patient. All aneurysms and occluded arterial segments remained occluded on follow-up imaging at 6 to 13 months, and none of the patients had infarctions in the medulla or territory of the posterior inferior cerebellar artery. Clinical outcome was excellent in 11 patients; 3 had cognitive impairment after SAH but were independent in daily activities. There were no episodes of recurrent hemorrhage.

CONCLUSION

Intradural vertebral dissecting aneurysms presenting with SAH should be treated promptly because of the high risk of recurrent hemorrhage. In our experience, trapping of the dissected segment with coils was straightforward, could be done in most patients, and was effective in preventing rebleeding. In our opinion, only in exceptional circumstances are more sophisticated techniques aimed at preservation of the parent artery necessary.

Treatment of vertebral artery aneurysms with transposition of the posterior inferior cerebellar artery to the vertebral artery combined with parent artery occlusion. Technical note

The authors describe transposition of the posterior inferior cerebellar artery (PICA) to the vertebral artery (VA) combined with parent artery occlusion for the treatment of VA aneurysms in cases in which a clip could not be applied because of the origin of the ipsilateral PICA. The aneurysm is trapped through a lower lateral suboccipital craniectomy. The PICA is then cut just distal to the aneurysm, and the PICA and VA proximal to the aneurysm are anastomosed in an end-to-end or end-to-side fashion. The surgical procedure was successfully performed in two patients, each of whom had hypoplastic occipital arteries (OAs). The PICA contralateral to the lesion was hypoplastic in one patient and distant to the ipsilateral PICA in the other patient. Mild transient dysphagia developed postoperatively in one patient due to glossopharyngeal and vagus nerve palsy, and the other patient had an uneventful postoperative course. In both patients, postoperative cerebral angiography demonstrated good patency of the transposed PICA. These results show that transposition of the PICA to the VA is a useful procedure for the reconstruction of the PICA when parent artery occlusion is necessary to exclude a VA aneurysm involving the origin of the PICA and when OA-PICA anastomosis or PICA-PICA anastomosis cannot be performed.

Treatment of a partially thrombosed giant aneurysm of the vertebral artery by aneurysm trapping and direct vertebral artery-posterior inferior cerebellar artery end-to-end anastomosis: technical case report

OBJECTIVE

The purpose of this article is to focus for the first time on the operative management of a direct vertebral artery (VA)-posterior inferior cerebellar artery (PICA) end-to-end anastomosis in a partially thrombosed giant VA-PICA-complex aneurysm and to underline its usefulness as an additional treatment option.

METHODS

The operative technique of a direct VA-PICA end-to-end anatomosis is described in detail. The VA was entering the large aneurysm sack. Distally, the PICA originated from the aneurysm sack-VA-complex. The donor and recipient vessel were cut close to the aneurysm. Whereas the VA was cut in a straight manner, the PICA was cut at an oblique 45-degree angle to enlarge the vascular end diameter. Vessel ends were flushed with heparinized saline and sutured. The thrombotic material inside the aneurysm sack was removed and the distal VA clipped, leaving the anterior spinal artery and brainstem perforators free.

RESULTS

The patient regained consciousness without additional morbidity. Magnetic resonance imaging scans revealed a completely decompressed brainstem without infarction. The postoperative angiograms demonstrated a good filling of the anastomosed PICA.

CONCLUSION

Despite the caliber mistmatch of these two vessels the direct VA-PICA end-to-end anastomosis provides an accurate alternative in addition to other anastomoses and bypass techniques, when donor and recipient vessels are suitable and medullary perforators do not have to be disrupted.

Treatment of ruptured fusiform aneurysm in the posterior cerebral artery with posterior cerebral artery-superior cerebellar artery anastomosis combined with parent artery occlusion: case report

BACKGROUND

Surgical management of a fusiform aneurysm in the PCA sometimes requires occlusion of the parent artery. In such cases, reconstruction of the PCA may prevent the development of postoperative visual field defects.

CASE DESCRIPTION

A 30-year-old woman with a fusiform aneurysm in the P2 of the left PCA presented with subarachnoid hemorrhage. The left superficial temporal artery and OA were hypoplastic. Left temporal craniotomy revealed that the lateromesencephalic ambient segment of the SCA and the posterior half portion of the P2 segment ran parallel and near each other, and that the calibers of both arteries were relatively consistent. Thus, the 2 arteries were anastomosed in a side-to-side fashion, and the anterior half of the left P2 segment was occluded by clipping proximal and distal to the aneurysm that was located at the left P2 segment just distal to the junction to the posterior communicating artery. The patient had an uneventful postoperative course, and postoperative cerebral angiography demonstrated resolution of the aneurysm, with perfusion of the left PCA from the left SCA via the anastomosis.

CONCLUSIONS

Posterior cerebral artery-superior cerebellar artery anastomosis is a useful method of achieving PCA reconstruction in the context of a PCA aneurysm requiring occlusion of the parent vessel and when superficial temporal artery or OA-PCA anastomosis cannot be performed.

Revascularization with saphenous vein bypasses for complex intracranial aneurysms

Most intracranial aneurysms can be managed with either microsurgical clipping or endovascular coiling. A subset of complex aneurysms with aberrant anatomy or fusiform/dolichoectatic morphology may require revascularization as part of a strategy that occludes the aneurysm or parent artery or both. Bypass techniques have been invented to revascularize nearly every intracranial artery. An aneurysm that will require a saphenous vein bypass is one that cannot be treated with conventional microsurgical clipping or endovascular coiling and also requires deliberate sacrifice of a major intracranial artery as part of the alternative treatment strategy. In the past 7 years the senior author (MTL) has performed a total of 110 bypasses, of which 46 were for aneurysms. Twenty-two of these patients received high-flow extracranial-to-intracranial bypasses using saphenous vein grafts, of which 16 had aneurysms that were giant in size. We review the indications for saphenous vein bypasses for complex intracranial aneurysms, surgical techniques, and clinical management strategies.

In Situ Bypass in the Management of Complex Intracranial Aneurysms: Technique Application in 13 Patients

OBJECTIVE:

Cerebral revascularization is an important part of the treatment of complex intracranial aneurysms that require deliberate occlusion of a parent artery. In situ bypass brings together intracranial donor and recipient arteries that lie parallel and in close proximity to one another rather than using an extracranial donor artery. An experience with in situ bypasses was retrospectively reviewed.

METHODS:

Thirteen aneurysms were treated with in situ bypasses between 1997 and 2004. During this time, 1071 aneurysms were treated microsurgically and 46 bypasses were performed as part of the aneurysm treatment.

RESULTS:

Treated aneurysms were located at the middle cerebral artery (MCA) in five patients, posteroinferior cerebellar artery (PICA) in three patients, vertebral artery in three patients, and anterior communicating artery in two patients. Seven aneurysms were fusiform or dolichoectatic, and six aneurysms were saccular. Microsurgical revascularization techniques included side-to-side anastomosis of intracranial arteries in eight patients and aneurysm excision with end-to-end reanastomosis of the parent artery in five patients. In situ bypasses included A3–A3 anterior cerebral artery bypass in two patients, anterior temporal artery-MCA bypass in one patient, MCA–MCA bypass in one patient, and PICA–PICA bypass in four patients. Aneurysm excision with arterial reanastomosis included three MCA aneurysms and two PICA aneurysms. On angiography, all aneurysms were completely obliterated and 12 bypasses were patent.

CONCLUSION:

In situ bypass is a safe and effective alternative to extracranial-intracranial bypasses and high-flow bypasses using saphenous vein or radial artery grafts. Although in situ bypasses are more demanding technically, they do not require harvesting a donor artery, can be accomplished with one anastomosis, and are less vulnerable to injury or occlusion.