David J. Langer

Internal maxillary artery-middle cerebral artery bypass: infratemporal approach for subcranial-intracranial (SC-IC) bypass.

BACKGROUND: Internal maxillary artery (IMax)–middle cerebral artery (MCA) bypass has been recently described as an alternative to cervical extracranial-intracranial bypass. This technique uses a “keyhole” craniectomy in the temporal fossa that requires a technically challenging end-to-side anastomosis. OBJECTIVE: To describe a lateral subtemporal craniectomy of the middle cranial fossa floor to facilitate wide exposure of the IMax to facilitate bypass. METHODS: Orbitozygomatic osteotomy is used followed by frontotemporal craniotomy and subsequently laterotemporal fossa craniectomy, reaching its medial border at a virtual line connecting the foramen rotundum and foramen ovale. The IMax was identified by using established anatomic landmarks, neuronavigation, and micro Doppler probe (Mizuho Inc. Tokyo, Japan). Additionally, we studied the approach in a cadaveric specimen in preparation for microsurgical bypass. RESULTS: There were 4 cases in which the technique was used. One bypass was performed for flow augmentation in a hypoperfused hemisphere. The other 3 were performed as part of treatment paradigms for giant middle cerebral artery aneurysms. Vein grafts were used in all patients. The proximal anastomosis was performed in an end-to-side fashion in 1 patient and end-to-end in 3 patients. Intraoperative graft flow measured with the Transonic flow probe ranged from 20 to 60 mL/min. Postoperative angiography demonstrated good filling of the graft with robust distal flow in all cases. All patients tolerated the procedure well. CONCLUSION: IMax to middle cerebral artery subcranial-intracranial bypass is safe and efficacious. The laterotemporal fossa craniectomy technique resulted in reliable identification and wide exposure of the IMax, facilitating the proximal anastomosis. ABBREVIATIONS: EC-IC, extracranial-intracranial IMax, internal maxillary artery MCA, middle cerebral artery SC-IC, subcranial-intracranial STA, superficial temporal artery

Erratum to: Superselective intraarterial cerebral infusion of cetuximab after osmotic blood/brain barrier disruption for recurrent malignant glioma: phase I study

Objective To establish a maximum tolerated dose of superselective intraarterial cerebral infusion (SIACI) of Cetuximab after osmotic disruption of the blood–brain barrier (BBB) with mannitol, and examine safety of the procedure in patients with recurrent malignant glioma.

Bypass for the Prevention of Ischemic Stroke

OBJECTIVEnAlthough most ischemic strokes are thromboembolic in origin and their management is endovascular or medical, some are hemodynamic in origin and their management may be surgical. Extracranial-intracranial bypass with superficial temporal artery-to-middle cerebral artery (MCA) bypass, high-flow interposition grafts, and reconstructive techniques have been developed. Clinical indications and efficacy are controversial, and this review examines current practices.nnnMETHODSnBypass surgery is indicated for patients with athero-occlusive disease that results in chronic, low cerebral blood flow accompanied by episodes of ischemic symptoms. Specific diagnoses include: (1) internal carotid artery occlusion; (2) MCA occlusion and, rarely, high-grade MCA stenosis; (3) vertebrobasilar atherosclerotic steno-occlusive disease; (4) vasculitis resulting in severe occlusive disease; and (5) moyamoya disease.nnnRESULTSnDiscouraging results from the Extracranial-Intracranial Bypass Trial demonstrated the importance of selecting surgical patients based on objective measures of hemodynamic insufficiency. Two such tests are xenon-enhanced computed tomography with acetazolamide challenge and positron emission tomography with measurement of oxygen extraction fraction. Perfusion computed tomography may be another, more practical test. Surgical series, systematic reviews of the literature, and two new randomized clinical trials that use these diagnostic techniques reveal contradictory results. Although they demonstrate that bypass surgery has a morbidity rate of less than 5% and a patency rate of more than 95%, they have not proven a clear benefit.nnnCONCLUSIONSnPatients with athero-occlusive disease and symptoms of hemodynamic insufficiency have significant risk of stroke if left untreated or managed medically. On the other hand, surgical intervention lacks supporting evidence. Clinicians must individualize their management recommendations until additional data are published or further consensus develops.

How I do it: combined direct (STA-MCA) and indirect (EDAS) EC-IC bypass

BackgroundEC-IC bypass for the treatment of a hypoperfused hemisphere is currently the treatment of choice for symptomatic moyamoya patients. Use of the combination of direct (STA-MCA) and indirect (an STA branch lay-on bypass and flipped dural flaps; EDAS) EC-IC bypass is advocated as the optimal treatment option as it allows immediate augmentation of flow in the postoperative period while allowing the brain to acquire additional indirect flow in the long term.MethodsWe describe the technical nuances of a combined direct and indirect bypass in a 41-year-old woman with moyamoya syndrome diagnosed with transient ischemic attacks (TIAs) and cognitive decline.ConclusionCombined direct and indirect bypass option should become a familiar treatment modality among vascular neurosurgeons.Key Points(1) Pay critical attention to not injuring the Superficial Temporal Artery, Parietal branch (STApb) while turning the skin incision anteriorly. Use the operating microscope to dissect the STApb.(2) Always mark the origin of the Superficial Temporal Artery, Frontal branch (STAfb) on the skin so that its location can be anticipated during STApb dissection.(3) When no frontal branch is available or if the frontal branch is of poor quality, the STApb can be used as a direct or indirect graft.(4) A craniotomy should be done 2–3xa0cm posterior to the course of the STApb to allow for adequate exposure for an indirect graft.(5) Manipulation of the donor vessels should be done with extreme care as spasm of the artery or intraluminal thrombosis may occur. Low cut flow in the direct graft should be interpreted with caution as vasospasm can result in significant temporary reduction of flow.(6) Aggressive distal dissection of the direct donor is a must. The distal 1–2xa0cm of the vessel should be cleaned of any loose tissue and be fishmouthed prior to anastomosis.(7) A blood-free field is mandatory. Perforators on the backside of the recipient should be sacrificed and cut to avoid backbleeding into the anastomotic segment during temporary occlusion.(8) When recirculating after the anastomosis has been completed, open the temporary clips on the recipient first. Backflow into the donor segment confirms a patent anastomosis.(9) Utilization of intraoperative angiography is not necessary as long as one utilizes flow measurements and ICG angiography.(10) Take great care with the bone flap reconstruction and the skin closure as the grafts can easily be compressed or sutured. Create a generous craniectomy in the bone flap to avoid any graft compression.

Posterior Inferior Cerebellar Artery to Posterior Inferior Cerebellar Artery In Situ Bypass for the Treatment of Bow Hunter's-Type Dynamic Ischemia in Holovertebral Dissection

BACKGROUNDnBow hunters syndrome is a rare cause of vertebrobasilar insufficiency arising from mechanical compression of the vertebral artery (VA) during rotation of the head. Surgical treatment usually involves direct decompression of the VA at the site of compression. We describe what is to our knowledge the first reported case of a posterior inferior cerebellar artery (PICA)-to-PICA in situ bypass for treatment of Bow hunters-type ischemia in a patient with a VA dissection.nnnCASE DESCRIPTIONnThe patient was a 41-year-old man who developed disabling symptoms of vertebrobasilar insufficiency after trauma when he rotated his head to the right. Dynamic angiography demonstrated a chronic dissection and stasis of flow in the right VA when his head was rotated to the right, with no obvious site of focal compression. The right VA ended in the PICA and the left VA was of good caliber. A single-photon emission computed tomography study with acetazolamide challenge confirmed brainstem ischemia and poor cerebrovascular reserve. He ultimately underwent a PICA-to-PICA in situ bypass to revascularize his right PICA territory with complete symptom resolution.nnnCONCLUSIONSnThe PICA-to-PICA in situ bypass is a useful option in the treatment of Bow hunters-type ischemia in the absence of focal structural compression of the VA or VA stenosis.

Safety and Efficacy of a 3-Dimensional Stent Retriever With Aspiration-Based Thrombectomy vs Aspiration-Based Thrombectomy Alone in Acute Ischemic Stroke Intervention: A Randomized Clinical Trial

Importance The treatment effects of individual mechanical thrombectomy devices in large-vessel acute ischemic stroke (AIS) remain unclear. Objective To determine whether the novel 3-dimensional (3-D) stent retriever used in conjunction with an aspiration-based mechanical thrombectomy device (Penumbra System; Penumbra) is noninferior to aspiration-based thrombectomy alone in AIS. Design, Setting, and Participants This randomized, noninferiority clinical trial enrolled patients at 25 North American centers from May 19, 2012, through November 19, 2015, with follow-up for 90 days. Adjudicators of the primary end points were masked to treatment allocation. Patients with large-vessel intracranial occlusion AIS presenting with a National Institutes of Health Stroke Scale (NIHSS) score of at least 8 within 8 hours of onset underwent 1:1 randomization to 3-D stent retriever with aspiration or aspiration alone. The primary analyses were conducted in the intention-to-treat population. Interventions Mechanical thrombectomy using intracranial aspiration with or without the 3-D stent retriever. Main Outcomes and Measures The primary effectiveness end point was the rate of a modified Thrombolysis in Cerebral Infarction (mTICI) grade of 2 to 3 with a 15% noninferiority margin. Device- and procedure-related serious adverse events at 24 hours were the primary safety end points. Results Of 8082 patients screened, 198 patients were enrolled (111 women [56.1%] and 87 men [43.9%]; mean [SD] age, 66.9 [13.0] years) and randomized, including 98 in the 3-D stent retriever with aspiration groupu2009and 100 in the aspiration alone group; an additional 238 patients were eligible but not enrolled. The median baseline NIHSS score was 18.0 (interquartile range, 14.0-23.0). Eighty-two of 94 patients in the 3-D stent retriever and aspiration group (87.2%) had an mTICI grade of 2 to 3 compared with 79 of 96 in the aspiration alone group (82.3%; difference, 4.9%; 90% CI, −3.6% to 13.5%). None of the other measures were significantly different between the 2 groups. Device-related serious adverse events were reported by 4 of 98 patients in the 3-D stent retriever with aspiration group (4.1%) vs 5 of 100 patients in the aspiration only group (5.0%); procedure-related serious adverse events, 10 of 98 (10.2%) vs 14 of 100 (14.0%). A 90-day modified Rankin Scale score of 0 to 2 was reported by 39 of 86 patients in the 3-D stent retriever with aspiration group (45.3%) vs 44 of 96 patients in the aspiration only group (45.8%). Conclusions and Relevance The present study provides class 1 evidence for the noninferiority of the 3-D stent retriever with aspiration vs aspiration alone in AIS. Future trials should evaluate whether these results can be generalized to other stent retrievers. Trial Registration clinicaltrials.gov Identifier: NCT01584609

Neuro-oncology biotech industry progress report.

The Brain Tumor Biotech Center at the Feinstein Institute for Medical Research, in collaboration with Voices Against Brain Cancer hosted The Brain Tumor Biotech Summit at in New York City in June 2015. The focus was once again on fostering collaboration between neuro-oncologist, neurosurgeons, scientists, leaders from biotechnology and pharmaceutical industries, and members of the financial community. The summit highlighted the recent advances in the treatment of brain tumor, and specifically focused on targeting of stem cells and EGFR, use of prophage and immunostimulatory vaccines, retroviral vectors for drug delivery, biologic prodrug, Cesium brachytherapy, and use of electric field to disrupt tumor cell proliferation. This article summarizes the current progress in brain tumor research as presented at 2015 The Brain Tumor Biotech Summit.

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

BACKGROUNDnFor 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.nnnOBJECTIVEnTo evaluate the clinical features, surgical techniques, and outcome of PICA aneurysms treated with bypass and obliteration of the diseased segment.nnnMETHODSnRetrospective 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.nnnRESULTSnSeven 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.nnnCONCLUSIONnConstructive 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.

Management of Complex Intracranial Aneurysms: Principles of Microsurgical Deconstruction and Cerebrovascular Bypass

Abstract Intracranial aneurysms may exhibit features that make them unsuitable for standard microsurgical and endovascular reconstructive strategies. For such lesions, deconstruction of the aneurysm and parent artery is often required, typically in association with a flow-replacement by pass procedure. The addition of a bypass helps minimize the risk of cerebral ischemia and infarction, particularly in the setting of subarachnoid hemorrhage (SAH). In this chapter, we present our management strategies for complex intracranial aneurysms and some of the technical nuances of microsurgical trapping and cerebral revascularization.

Frameless and Maskless Stereotactic Navigation with a Skull-Mounted Tracker

OBJECTIVEnIn this series, we present 3 cases that show the use of a skull-mounted tracker for image-guided navigation for anterior skull base surgery and ventricular catheter placement procedures. This system obviates fiducials or face masks during the surgical procedure itself and allows for the performance of facial incisions using the Weber-Ferguson approach.nnnMETHODSnOur series presents the use of a novel intraoperative navigational system that uses a skull-mounted tracker to navigated anterior skull base surgery.nnnRESULTSnWe present 3 cases using this new system: 1 anterior skull base tumor removal that was operated on without a facemask for navigation and 2 ventricular catheter placement procedures.nnnCONCLUSIONSnIntraoperative image-guided navigation has revolutionized neurosurgery. It undoubtedly increases the surgeons confidence and the perception of safety. Although fiducials and facial masks are the most widely used tools for intraoperative navigation, their use is associated with certain complications. This technique permits free movement of the head during surgery, which in turn facilitates the exposure of head and neck lesions and expedites the approach to ventricular catheter placement. Our case series shows the precision and ease of our technique, which is less time consuming and less cumbersome than the traditional frame-based stereotaxy. In addition, the skull-mounted tracker system allows improved anatomic localization and shorter operating time and avoids the complications associated with the use of rigid fixating head frames.