Interdisciplinary treatment of posterior fossa dural arteriovenous fistulas.

BACKGROUND: Posterior fossa dural arteriovenous fistulas (dAVFs) are rare vascular lesions with variable risk of hemorrhage, mostly depending on the pattern of the venous drainage. While endovascular embolization is the mainstay treatment for most dAVFs, some posterior fossa lesions require a multidisciplinary approach including surgery. The goal of our study was to examine the outcome of an interdisciplinary treatment for posterior fossa dAVFs. METHODS: A retrospective review of patients treated for posterior fossa dAVFs was conducted. RESULTS: A total of 28 patients with a mean age of 57.8 years were included. Patients presented with a Cognard grade I in 2 (7%), II a in 5 (18 %), II b in 7 (25%), II a + b in 5 (18%), III in 3 (11%), and IV in 6 (21%) cases. Hemorrhage was the initial presentation in 2 (22%) patients with Cognard grade IV, in 3 with Cognard grade III (33%), in 1 (11%) with Cognard II a + b, and 3 (33%) with Cognard II b. A complete angiographic cure was achieved in 24 (86%) patients-after a single-session embolization in 16 (57%) patients, multiple embolization sessions in 2 (7%), a multimodal treatment with embolization and surgical disconnection in 3 (11%), and with an upfront surgery in 3 (11%). Complete long-term obliteration was demonstrated in 18/22 (82%) at the mean follow-up of 17 months. Fistulas were converted into asymptomatic Cognard I lesion in 4 (14%) patients. CONCLUSION: Posterior fossa dAVFs represent a challenging vascular pathology; however, despite their complexity, an interdisciplinary treatment can achieve high rates of angiographic and symptomatic cure with low morbidity and mortality rates. Long-term surveillance is warranted as late recurrences may occur.

Trapping and resection of cortical MCA mycotic aneurysm in eloquent area.

BACKGROUND: Mycotic aneurysms, although well recognized, are relatively rare intracranial vascular pathology. These aneurysms are typically located in distal cortical vessels. When these aneurysms are located in eloquent cerebral territories, they may become challenging to treat. Eloquent location may necessitate intraoperative angiographic evaluation to verify complete aneurysmal occlusion/obliteration and preservation of normal adjacent vasculture. Recently, ICG videoangiography has become a widely used intra-operative adjunct and is an important tool used to assess complete occlusion and vessel patency at the conclusion of clip reconstruction. In this report, we outline the comprehensive and concurrent utilization of both vascular imaging modalities to ensure safe and complete occlusion of a mycotic aneurysm. METHODS: We describe our experience with a patient with left M4, Rolandic, enlarging mycotic aneurysm that was treated in a comprehensive fashion with microsurgery and intra-operative angiography (IA). CONCLUSIONS: ICG videoangiography, in combination with concurrent intraoperative angiography in the setting of complex vascular lesions, may support intraoperative decision-making and provide demonstration of complete occlusion in an immediate fashion. A hybrid operative suite allows for high-quality imaging confirming complete resection.

Paradigms for single-patient multimodality treatment for cerebral aneurysms: single-center eleven-year experience.

Endovascular and surgical techniques are conventional options for treating intracranial aneurysms, but criteria for selecting an optimal approach for individual patients remain variable across practitioners and institutions. While endovascular and surgical approaches are generally used alone, both modalities combined in single patients can produce efficacious outcomes. The aim of this study was to evaluate outcomes of combined, concomitant endovascular and surgical modalities in the treatment of multiple and/or complex aneurysms in single patients. Indications, sequencing rationale, and categorization for multimodality treatments are reviewed. All intracranial aneurysms treated at our institution from 2004 to 2014 were reviewed. Single patients who had undergone concomitant endovascular and surgical treatments were eligible for participation in our study. Demographic data and clinical presentation parameters, including location, size, and morphological features of lesions, treatment sequencing, and outcomes were recorded. Our cohort consisted of 27 patients with 57 aneurysms who received concomitant endovascular and surgical treatment of their aneurysm(s). One patient arrived to us after he had an aneurysm clipped at an outside institution and then required treatment for a contralateral ruptured aneurysm. 66.7% of patients were diagnosed with subarachnoid hemorrhage. These were subdivided according to therapeutic approach: clipping and coiling (CL+CO), clipping and stenting (CL+ST), bypass and endovascular parent vessel occlusion (PVO) (BY+PVO), attempted clipping then stenting, and bypass followed by stenting. Glasgow Outcome Scale was as follows: CL-CO-Multiple, 4.17 (five in unruptured patients, 3.75 in ruptured); CO-CL-Multiple, five (all patients had a ruptured aneurysm); CL-CO-Single, three (all patients had a ruptured aneurysm); CO-CL-Single, five (all patients had a ruptured aneurysm). No patients suffered a new neurological deficit as a result of treatment. A total of two mortalities were documented. Concomitant, mutimodality endovascular and surgical therapy may offer a safe and potentially more effective paradigm than single modality approaches for the management of multiple, complex, or "failed" aneurysm treatments in selected patients.

Analysis of superiorly projecting anterior communicating artery aneurysms: anatomy, techniques, and outcome. A proposed classification system.

Superiorly projecting (SP) anterior communicating artery (AComA) aneurysms are typically described as a homogenous group. Clinically and microsurgically, these aneurysms vary in multiple important characteristics. We propose a microsurgical classification system for these complex aneurysms and review its implications regarding presentation, microsurgical techniques, and outcome. This retrospective analysis reviews patients undergoing clipping of SP AComA aneurysms (2005-2013). The classification system is based on the virtual plane created by the A2 segments and its relationship to the aneurysm. Aneurysm type was assessed by intraoperative images and videos. Type 1 is defined by bisection of the dome by the virtual plane. Type 2 is defined by dome projection posterior to this plane. Sagittal rotation of the plane defines type 3. We analyzed clinical presentation, morphology, angiographic characteristics, operative technique, and outcome relative to the classification types. There were 44 SP AComA aneurysms. 3D angiographic images predicted classification type in 83%. Type 1 presented more often with SAH (95.5%, p = 0.0046). There was no statistically significant difference between the types regarding patient demographics or aneurysm characteristics. In type 2, fenestrated clips were used frequently (87.5% p= 0.0016), and there was higher rate of intraoperative rupture (37.5%). Although there was no statistically significant difference between the types in respect to HH grade upon presentation, patients with type 2 aneurysms experienced higher rates of poor GOS (50%). The proposed classification system for SP AComA aneurysms has implications regarding surgical planning, micro-dissection, clipping, and outcome. Type 2 aneurysms carry significant surgical risk.

Supratentorial cortical ependymoma: case series and review of the literature.

Supratentorial cortical ependymoma (CE), a rare type of ependymoma, is located in the superficial cortex. We reported 11 patients (six female and five male) with CE. The age of the patients ranged from 2 to 63 years old with a median age of 47 years at the time of diagnosis. On MRI, enhancement was noted in all cases with solid appearance in six cases, and solid and cystic appearance in five cases. The frontal and parietal regions were the most common locations for CE. On histology, two were low-grade (WHO grade II) and nine were WHO grade III anaplastic ependymomas. Some tumors exhibited clear cell, spindle (tanycytic) and giant cell morphologies, as well as the classic ependymoma morphology. Dura-based tumor nodules and even tumor dissemination along the dura can be seen in CEs. Low grade CEs have a higher likelihood to present with seizures, a lower likelihood to cause brain edema, tumor recurrence and lower mortality than anaplastic ependymomas. While difficult, anaplastic CEs may be distinguished from glioblastoma by a clear interface between tumor and adjacent brain tissue, relative uniformity of tumor cell nuclei and immunopositivity for epithelial membrane antigen and/or CD99. As is the case for ependymomas in general, gross total resection is still the treatment of choice for CEs.

Anterior petroclinoid fold fenestration: an adjunct to clipping of postero-laterally projecting posterior communicating aneurysms.

Proximally located posterior communicating artery (PCoA) aneurysms, projecting postero-laterally in proximity to the tentorium, may pose a technical challenge for microsurgical clipping due to obscuration of the proximal aneurysmal neck by the anterior petroclinoid fold. We describe an efficacious technique utilizing fenestration of the anterior petroclinoid fold to facilitate visualization and clipping of PCoA aneurysms abutting this aspect of the tentorium. Of 86 cases of PCoA aneurysms treated between 2003 and 2013, the technique was used in nine (10.5 %) patients to allow for adequate clipping. A 3 mm fenestration in the anterior petroclinoid ligament is created adjacent and lateral to the anterior clinoid process. This fenestration is then widened into a small wedge corridor by bipolar coagulation. In all cases, the proximal aneurysm neck was visualized after the wedge fenestration. Additionally, an adequate corridor for placement of the proximal clip blade was uniformly established. All cases were adequately clipped, with complete occlusion of the aneurysm neck and fundus with preservation of the PCoA. There were two intraoperative ruptures not related to creation of the wedge fenestration. One patient experienced post-operative partial third nerve palsy, which resolved during follow-up. We describe a technique of fenestration of the anterior petroclinoid fold to establish a critical and safe corridor for both visualization and clipping of PCoA aneurysms.

Flow-based evaluation of cerebral revascularization using near-infrared indocyanine green videoangiography.

OBJECT: Indocyanine green (ICG) videoangiography has been established as a noninvasive technique to gauge the patency of a bypass graft; however, intraoperative graft patency may not always correlate with graft flow. Altered flow through the bypass graft may directly cause delayed graft occlusion. Here, the authors report on 3 types of flow that were observed through cerebral revascularization procedures. METHODS: Between February 2009 and September 2013, 48 bypass procedures were performed. Excluded from analysis were those cases in which ICG videoangiography was not performed during surgery (whether it was not available or there was a technical issue with the microscope or the quality of ICG angiography) and/or in which angiography or CT angiography was not done within 24-72 hours after surgery. After anastomosis, bypass patency was assessed first using a noninvasive technique and then with ICG videoangiography, and flow through the graft was characterized. Patients who received a vein or radial artery graft were also evaluated with intraoperative angiography. RESULTS: Thirty-three patients eligible for analysis were retrospectively analyzed. The patients had undergone extracranial-intracranial (EC-IC) or IC-IC bypass for ischemic stroke (13 patients), moyamoya disease (10 patients), and complex aneurysms (10 patients; 6 giant or large aneurysms, 2 carotid blister-like aneurysms, and 2 dissecting posterior inferior cerebellar artery [PICA] aneurysms). Thirty-six bypasses were performed including 26 superficial temporal artery (STA)-middle cerebral artery (MCA) bypasses (2 bilateral and 1 double-barrel), 6 EC-IC vein grafts, 1 EC-IC radial artery graft, 1 PICA-PICA bypass, 1 MCA-posterior cerebral artery bypass, and 1 occipital artery-PICA bypass. Robust anterograde flow (Type I) was noted in 31 grafts (86%). Delayed but patent graft enhancement and anterograde flow (Type II) was observed in 4 cases (11%); 1 of these cases with an EC-IC vein graft degraded gradually to very delayed flow with no continuity to the bypass site (Type III). Additionally, 1 STA-MCA bypass graft revealed no convincing flow (Type III). The 5 patients with Type II or III grafts were evaluated with a flow probe and reexploration of the bypass site, and in all cases the reason the graft became occluded was believed to be recipient-vessel competitive flow. In no case was there evidence of stenosis or a technical issue at the site of the anastomosis. Three patients with Type II and the 1 patient with Type III flow (11% of procedures) did not have a patent bypass on postoperative imaging. CONCLUSIONS: Indocyanine green videoangiography is reliable for evaluating flow through the EC-IC or IC-IC bypass. The type of flow observed through the graft has a direct relationship with postoperative imaging findings. Despite the possibility of competitive flow, Type III and some Type II flows through the graft indicate the need for graft evaluation and anastomosis exploration.

How I do it: occipital artery to posterior inferior cerebellar artery bypass.

BACKGROUND: Aneurysms located at the proximal posterior inferior cerebellar artery (PICA) may need to be addressed by trapping and concomitant bypass. An anastomosis of the Occipital Artery (OA) to PICA is one bypass option in these cases. This bypass is highly challenging and its technical description is seldom cited in the literature. METHODS: We describe the technical nuances of an OA-PICA end-to-side bypass in a 63-year-old man with a dissecting ruptured aneurysm of the third segment (tonsilomedullary) of the PICA. CONCLUSION: OA-PICA bypass option should remain as a treatment modality in the armamentarium of neurovascular surgeons.

Iatrogenic dural arteriovenous fistula and aneurysmal subarachnoid hemorrhage.

The authors present the case of a patient who presented acutely with aneurysmal subarachnoid hemorrhage (SAH) and a contralateral iatrogenic dural arteriovenous fistula (DAVF). Diagnostic angiography was performed, revealing a right-sided middle cerebral artery (MCA) aneurysm and a left-sided DAVF immediately adjacent to the entry of the ventriculostomy and bur hole site. A craniotomy was performed for clipping of the ruptured MCA aneurysm, and the patient subsequently underwent endovascular obliteration of the DAVF 3 days later. The authors present their treatment of an iatrogenic DAVF in a patient with an aneurysmal SAH, considerations in management options, and a literature review on the development of iatrogenic DAVFs.

Acquisition of Basic Microsurgical Skills Using Low-Cost, Readily Available Models: The Orange Model.

BACKGROUND: Attainment of basic microsurgical skills in neurosurgery presents a departmental challenge worldwide. Models for teaching are either not readily available or expensive and are incompatible with a resident's busy schedule, requiring lengthy and proper setup. We present a model and a set of measurable tasks, based on a fruit (orange) that is cheap, easy to set up instantly when desired, and useful for training of basic microsurgical skills. METHODS: Basic microsurgical skills were identified, necessitating hand-eye coordination working with the microscope. The goal was to dissect an orange segment while preserving adjacent segments. Assessment was based on the number of side tears and task completion duration. The task was repeated in a sequential manner (n = 10), for validation purposes, for 3 operators at different seniority levels. RESULTS: An improvement in the number of side tears (mean of 12.66 ± 9.01 in the first trial vs. 4 ± 4.35 in the 10th trial, P < 0.01), as well as duration of time required for task completion (mean initial duration of 28:16 ± 19:00 minutes to a duration of 16:33 ± 10:50 minutes in the last attempt, P < 0.01), was observed. Daily practice scores and time gradually improved, and the seniority level of operators was correlated with scoring between individuals. CONCLUSIONS: The orange model is an easily accessible, cheap model that enables the acquisition of basic microneurosurgical skills. In this work, we validated and defined reproducible tasks that can be scored and tracked, correlated with operator's proficiency and experience. This model can be incorporated into a resident's workflow environment and provides a platform for attainment of elementary microsurgical skills for neurosurgical residents.

Unilateral Venous Approach to Contralateral or Bilateral Carotid Cavernous Shunts.

BACKGROUND: Cavernous carotid fistulas (CCF) are anatomically complex vascular lesions. Treatment via the venous approach has been previously described and is highly dependent on the patency of the drainage pathways. The use of a unilateral approach to contralateral or bilateral shunts is technically challenging and not commonly described. We present our experience with the unilateral across-the-midline approach to both cavernous sinuses to treat shunts according to anatomic compartments to achieve anatomic cure. METHODS: Patients included in this study presented with either bilateral or unilateral shunts with unilateral venous drainage. We used a transarterial guiding catheter for road mapping and control angiography. A venous triaxial system was used to achieve support for distal navigation across the midline via the coronary sinus to the contralateral cavernous sinus. Coils were favored for embolization, with occasional complementary liquid embolic material. RESULTS: Five patients underwent complete occlusion in a single session. One patient required additional complementary transarterial embolization. Despite a successful unilateral approach to bilateral cavernous sinuses, 1 patient needed an additional ipsilateral transophthalmic venous approach to obliterate the anterior compartment of the cavernous sinus. No complications were encountered. Complete angiographic cure was observed in all patients by the end of the final procedures, with persistent occlusion in their follow-up imaging. CONCLUSIONS: Careful inspection of the venous anatomy and fistulization sites is critical when treating unilateral or bilateral carotid cavernous shunts. The contralateral venous route can serve as a safe approach when visualized. Crossing the midline via the anterior or posterior coronary sinuses is feasible and efficacious.

Rescue Craniectomy with Subsequent Cranioplasty for Recurrent Symptomatic Subdural Hematoma in Elderly Patients.

OBJECTIVE: Recurrent subdural hematoma (SDH) is commonly encountered in clinical practice. Multiple surgical techniques have been reported for management of recurrent SDH with variable success and complication rates. We report an alternative technique to halt SDH reaccumulation in elderly patients with multiple recurrences despite multiple surgical evacuations via rescue craniectomy and subsequent cranioplasty. METHODS: We retrospectively identified all symptomatic recurrent SDHs in elderly patients (≥60 years old) who were surgically managed with rescue craniectomy with subsequent cranioplasty from November 2004 to January 2018. Patients' demographics and radiologic and surgical variables were recorded and analyzed. RESULTS: Of 287 patients who received surgical treatment for SDH, 19 patients (6.6%) underwent SDH evacuation with rescue craniectomy and subsequent cranioplasty were included in the study. The median age of the cohort was 73 years (interquartile range: 62-78 years), with 13 men and 6 women. Trauma was the cause of SDH in most cases. Five patients had acute SDH, 4 patients had subacute SDH, and 10 patients had chronic SDH. Fourteen patients had only 1 recurrence of SDH requiring surgical re-evacuation, and 5 had 2 recurrences. Median interval between craniectomy and cranioplasty was 64.5 days (interquartile range: 15-123.3 days). Four complications were encountered. After cranioplasty, 15 patients had no further hemorrhage or recurrence and 4 patients had stable subdural collection during an average follow-up of 38.2 ± 46.9 months. CONCLUSIONS: Rescue craniectomy followed by cranioplasty is a safe and effective salvage technique for the management of symptomatic recurrent SDH in elderly patients.

Primary Low-Grade B-Cell Lymphoma of Skull With Translocation Between Immunoglobulin and Interferon Regulatory Factor 4 Genes.

Low-grade B-cell lymphoma with immunoglobulin (IG) and interferon regulatory factor 4 (IRF4) gene rearrangement is extremely rare, with only 4 cases being previously reported. In this article, we report one additional case that arises from the skull and review the literature. The patient was a 69-year-old man who presented with recurrent and disabling vertigo and was found to have a 5.0 × 1.7 cm lesion within the left posterior parietal bone. Histological examination revealed a bone lesion with diffuse lymphoid infiltrate comprising of mostly small lymphocytes with scant cytoplasm, slightly irregular nuclei and inconspicuous nucleoli, and scattered larger cells resembling prolymphocytes and paraimmunoblasts. Immunohistochemical studies showed that the neoplastic cells were positive for CD20, CD79a, PAX5, CD23, CD43, BCL-2, BCL-6, MUM-1, LEF-1, and IgM and negative for CD5, CD10, cyclinD1, SOX11, and IgD. Flow cytometric analysis identified CD5 negative and CD10 negative monoclonal B cells with lambda light chain restriction. Fluorescence in situ hybridization analysis revealed del(13q) abnormality, but was negative for IGH/BCL2, IGH/CCND1, and BIRC3/MALT1 translocations. Next-generation sequencing identified IGK-IRF4 rearrangement and BRD4 E1113 del abnormalities. Given a low clinical stage (IE) of the disease, the patient did not receive additional treatments and was free of disease at 1 year after the diagnosis.

Metastatic Subdural Hematoma with Dural Metastasis Secondary to Poorly Differentiated Adenocarcinoma of Unknown Origin.

BACKGROUND: Metastatic subdural hematoma with dural metastasis in the setting of an underlying malignancy is a rare condition that is difficult to diagnose and associated with a poor prognosis. Knowledge of this rare entity is of a paramount importance to neurosurgeons, as its diagnosis may affect the management plan and overall survival. Here, we report a rare case of atraumatic subdural hematoma with dural metastasis in a patient with poorly differentiated adenocarcinoma of unknown origin. CASE DESCRIPTION: A 34-year-old man presented with an insidious onset of headaches, severe light headedness, progressive low back pain, and generalized weakness for 2 weeks. On imaging, he was found to have left-sided acute on chronic subdural hematoma with midline shift. The patient underwent surgical evacuation of the hematoma and the subdural membrane was biopsied. Histopathologic examination revealed metastatic poorly differentiated adenocarcinoma of unclear origin. A full metastatic workup was unremarkable. CONCLUSIONS: Metastatic subdural hematoma with dural metastasis should be included in differential diagnosis of subdural hematoma, especially in patients with atypical presentation and in the presence of an underlying malignancy, as it may affect the management plan and overall survival.

Cerebrospinal fluid macrophage migration inhibitory factor: a potential predictor of cerebral vasospasm and clinical outcome after aneurysmal subarachnoid hemorrhage.

OBJECTIVE: In patients with aneurysmal subarachnoid hemorrhage (aSAH), poor outcomes have been shown to be correlated with subsequent cerebral vasospasm (CV) and delayed cerebral ischemia (DCI). The identification of novel biomarkers may aid in the prediction of which patients are vulnerable to developing vasospasm, cerebral ischemia, and neurological deterioration. METHODS: In this prospective clinical study at North Shore University Hospital, patients with aSAH or normal pressure hydrocephalus (NPH) with external ventricular drains were enrolled. The concentration of macrophage migration inhibitory factor (MIF) in CSF was assessed for correlation with CV or DCI, the primary outcome measures. RESULTS: Twenty-five patients were enrolled in the aSAH group and 9 were enrolled in the NPH group. There was a significant increase in aggregate CSF MIF concentration in patients with aSAH versus those with NPH (24.4 ± 19.2 vs 2.3 ± 1.1 ng/ml, p < 0.0002). Incidence of the day of peak MIF concentration significantly correlated with the onset of clinical vasospasm (rho = 0.778, p < 0.0010). MIF concentrations were significantly elevated in patients with versus those without evidence of DCI (18.7 ± 4.93 vs 8.86 ± 1.28 ng/ml, respectively, p < 0.0025). There was a significant difference in MIF concentrations between patients with infection versus those without infection (16.43 ± 4.21 vs 8.5 ± 1.22 ng/ml, respectively, p < 0.0119). CONCLUSIONS: Preliminary evidence from this study suggests that CSF concentrations of MIF are correlated with CV and DCI. These results, however, could be confounded in the presence of clinical infection. A study with a larger patient sample size is necessary to corroborate these findings.

Intraoperative Angiography for Arteriovenous Malformation Resection in the Prone and Lateral Positions, Using Upper Extremity Arterial Access.

BACKGROUND: Intraoperative angiography is routinely utilized for aneurysms and arteriovenous malformations (AVMs) to verify complete occlusion and resection. Surgery for spinal and posterior fossa neurovascular lesions is usually performed in prone position. Intraoperative angiography in the prone position is challenging and there is no standardized protocol for this procedure. OBJECTIVE: To describe our experience with intraoperative angiography in the prone and lateral positions, using upper extremity arterial access. METHODS: We reviewed our experience with intraoperative angiography in the prone position between 2014 and 2015, where vascular access was obtained via the upper extremity arteries. Patients were treated in a hybrid endovascular operating room. High cervical and intracranial lesions were studied via brachial or radial access. All accesses were obtained using ultrasonographic guidance and a small caliber arterial sheath (4F). RESULTS: Five patients were treated in the prone and lateral positions using brachial/radial artery access. Patients harbored cerebellar AVM, lateral medullary AVM, cervical arteriovenous fistula (AVF), tentorial dural AVF, and tentorial-incisural dural AVF. Patients were positioned prone (n = 2), semiprone (n = 2), and lateral (n = 1) for the surgery. Three patients were treated via right brachial artery access. Two patients were treated via radial arteries access. All patients tolerated the procedures without technical or clinical complications. Intraoperative angiography verified complete occlusion and resection in all cases prior to surgical closure. CONCLUSIONS: Intraoperative angiography in the prone and lateral positions using upper extremity access is an important adjunct. Brachial or radial access can be obtained safely and provides comfortable and quick approaches.

Treatment of distal anterior cerebral artery aneurysms with the Pipeline Embolization Device.

Aneurysms of the anterior cerebral artery (ACA) located distal to the anterior communicating artery complex (ACOM) remain challenging to treat with surgical clip reconstruction as well as with endovascular coil-embolization strategies. We have treated five complex geometry distal ACA aneurysms with endoluminal reconstruction using the Pipeline Embolization Device (PED). Two aneurysms were of the dysplastic fusiform type. Three aneurysms were of complex saccular configuration. Three aneurysms were treated electively at the outset with PED. One patient had previously undergone aborted clip reconstruction, and one was treated for recurrent aneurysm growth after coil embolization. The mean diameter of the ACA in this cohort was 1.96mm proximal to the aneurysm and 1.79mm distal to the aneurysmal segment. A single PED of 2.5mm inner diameter was the sole treatment in four cases. Two PEDs, telescopically overlapped across the aneurysm, were used in the remaining case. All devices were deployed successfully. No parent artery occlusion or stenosis was observed. In all cases an associated branch vessel arising from the vicinity of the aneurysm or incorporated into its neck was covered by the endoluminal construct. At follow-up angiography, robust antegrade flow was maintained in the jailed branch. One patient experienced asymptomatic, delayed occlusion of the jailed branch. Complete aneurysm occlusion was seen in all patients. We confirm that PED can be deployed in parent vessels smaller than 2mm diameter, and that endoluminal reconstruction with the PED may be a safe and effective treatment alternative for selected distal ACA aneurysms.

Intracranial Bypass of Posterior Inferior Cerebellar Artery Aneurysms: Indications, Technical Aspects, and Clinical Outcomes.

BACKGROUND: For some posterior inferior cerebellar artery (PICA) aneurysms, there is no constructive endovascular or direct surgical clipping option. Intracranial bypass is an alternative to a deconstructive technique. OBJECTIVE: To evaluate the clinical features, surgical techniques, and outcome of PICA aneurysms treated with bypass and obliteration of the diseased segment. METHODS: Retrospective review of PICA aneurysms treated via intracranial bypass was performed. Outcome measurements included postoperative stroke, cranial nerve deficits, gastrostomy/tracheostomy requirement, bypass patency, modified Rankin scale (mRS) at discharge, and mRS at 6 mo. RESULTS: Seven patients with PICA aneurysms treated with intracranial bypass were identified. Five had fusiform aneurysms (4 ruptured, 1 unruptured), 1 had a giant partially thrombosed saccular aneurysm (unruptured), and 1 had a dissecting traumatic aneurysm (ruptured). Two aneurysms were at the anteromedullary segment, 4 at the lateral medullary segment, and 1 at the tonsillomedullary segment. Three patients underwent PICA-to-PICA side to side anastomoses, 2 PICA-to-PICA reanastomosis, 1 vertebral artery-to-PICA bypass, and 1 occipital artery-PICA bypass. Six out of 7 aneurysms were obliterated surgically and 1 with additional endovascular occlusion after the bypass. All bypasses were patent intraoperatively; 2 were later demonstrated occluded without radiological signs or symptoms of stroke. No patients had new cranial nerve deficit postoperatively. With the exception of 1 death due to pulmonary emboli 3 mo postoperatively, all others remain at a mRS ≤ 2. CONCLUSION: Constructive bypass and aneurysm obliteration remains a viable alternative for treatment of PICA aneurysms not amenable to direct surgical clipping or to a vessel-preserving endovascular option.

Angiographic Evidence of a Purely Pial Bihemispheric Intracranial Hemangiopericytoma.

Background. Classification of hemangiopericytoma (HPC) has evolved to a mesenchymal, nonmeningothelial grade two or three neoplasm according to the World Health Organization; however its blood supply has always been defined by dual origin, pial and dural contribution. Case Description. We present the case of a patient with an intracranial HPC with only pial vascular supply. Angiography confirmed the lack of dural supply to this bihemispheric intracranial mass. Subsequent histologic examination confirmed the diagnosis of hemangiopericytoma. Angiographic evidence here is atypical of the natural history of hemangiopericytomas with dual vascular supply and was critical in the decision-making towards surgical resection without tumor embolization. Conclusion. Data presented suggests the lack of dural vascular supply alone does not rule out the diagnosis of hemangiopericytoma.

Forearm Cephalic Vein Graft for Short, "Middle"-Flow, Internal Maxillary Artery to Middle Cerebral Artery Bypass.

BACKGROUND: The cervical carotid system has been used as a source of donor vessels for radial artery or saphenous vein grafts in cerebral bypass. Recently, internal maxillary artery to middle cerebral artery bypass has been described as an alternative, with reduction of graft length potentially correlating with improved patency. OBJECTIVE: To describe our experience using the forearm cephalic vein grafts for short segment internal maxillary artery to middle cerebral artery bypasses. METHODS: All vein grafts were harvested from the volar forearm between the proximal cubital fossa where the median cubital vein is confluent with the cephalic vein and the distal wrist. RESULTS: Six patients were treated with internal maxillary artery to middle cerebral artery bypass. In 4, the cephalic vein was used. Postoperative angiography demonstrated good filling of the grafts with robust distal flow. There were no upper extremity vascular complications. All but 1 patient (mortality) tolerated the procedure well. The other 3 patients returned to their neurological baseline with no new neurological deficit during follow-up. CONCLUSION: The internal maxillary artery to middle cerebral artery "middle" flow bypass allows for shorter graft length with both the proximal and distal anastomoses within the same microsurgical field. These unique variable flow grafts represent an ideal opportunity for use of the cephalic vein of the forearm, which is more easily harvested than the wider saphenous vein graft and which has good match size to the M1/M2 segments of the middle cerebral artery. The vessel wall is supple, which facilitates handling during anastomosis. There is lower morbidity potential than utilization of the radial artery. Going forward, the cephalic vein will be our preferred choice for external carotid-internal carotid transplanted conduit bypass.