Endovascular reconstruction of extracranial traumatic internal carotid artery dissections: a systematic review.

Extracranial internal carotid artery dissection (ICAD) is a potential source of morbidity and mortality in trauma patients and requires high degree of suspicion for diagnosis after the initial presentation. Occasionally, if standard therapy is contraindicated, endovascular reconstruction is a treatment option. The aim of this systematic review was to report clinical and radiographic outcomes following endovascular repair of ICAD of traumatic and iatrogenic etiology. A comprehensive systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. PubMed and Cochrane Library databases were searched. Twenty-four studies comprising 191 patients (204 lesions) were included; 179 underwent traditional carotid artery stenting (CAS), whereas 12 patients underwent flow diversion with the pipeline embolization device (PED). In total, 75.7% of the CAS group and 66.6% of the PED group presented with ICAD-related symptomatology. Concomitant pseudoaneurysms were identified in 61.9% and 78.5% of lesions in the CAS and PED group, respectively. Adverse event rates among CAS-treated lesions after 30-day follow-up were below 2.2% for stroke, transient ischemic attack, and mortality. During follow-up in the CAS group, there was no incidence of ICAD-related stroke or death and 2.2% of patients underwent a repeat CAS procedure. In the PED group, no patient suffered stroke or death in the reported follow-up. In the PED cohort, there was an adequate occlusion rate and no patient had to be retreated. Endovascular reconstruction of traumatic or iatrogenic ICAD appears safe. This approach demonstrated acceptable short- and long-term clinical and radiographic outcomes in both groups.

How I do it: surgical clip reconstruction of a large, partially thrombosed, ruptured middle cerebral artery aneurysm.

BACKGROUND: Ruptured large and partially thrombosed aneurysms are challenging lesions to treat successfully. METHODS: We describe the surgical treatment of a large, ruptured partially thrombosed middle cerebral artery (MCA) aneurysm. Once the Sylvian fissure is dissected, temporary clips are placed, and the clot is evacuated with simple microsuction and ultrasonic aspiration. The aneurysm is then carefully clip reconstructed to avoid compromise of the parent vessels. CONCLUSION: In cases of surgical clipping of large, thrombosed aneurysms, it is important to be aware of a few, but critically important, pitfalls to ensure successful outcome.

Direct Transcervical Access vs the Transfemoral Approach for Carotid Artery Stenting: A Systematic Review and Meta-Analysis.

PURPOSE: To examine the safety profile of transcervical access (TCA) in comparison with the transfemoral approach (TFA) in carotid artery stenting. MATERIALS AND METHODS: A systematic review and meta-analysis was performed according to current guidelines. Eleven eligible studies including 11,592 patients (10,736 in the TFA group and 856 in the TCA group) were identified through a search of the PubMed, Scopus, and Cochrane databases up to October 2018. A random effects model meta-analysis was conducted, and the I2 statistic was used to assess heterogeneity. Publication bias was assessed using funnel plots and quantified using the Egger method. RESULTS: The TFA group had a statistically significantly higher risk of periprocedural (30-day) stroke compared with the TCA group (OR 1.98, 95% CI 1.08 to 3.63, p=0.027; I2=0%). Also, patients in the TFA group had a significantly higher risk of developing new ischemic lesions (OR 2.97, 95% CI 1.48 to 5.96, p=0.002; I2=0%) on diffusion-weighted magnetic resonance imaging (DW-MRI). No differences in terms of transient ischemic attack (OR 1.50, 95% CI 0.73 to 3.10, p=0.268; I2=5.9%), myocardial infarction (OR 0.64, 95% CI 0.30 to 1.35; p=0.242; I2=0%), local hematoma (OR 0.53, 95% CI 0.12 to 2.25, p=0.389; I2=0%), or mortality (OR 1.35, 95% CI 0.62 to 2.92, p=0.449; I2=0%) were identified between the groups. CONCLUSION: TCA is associated with a significantly lower risk for periprocedural stroke and DW-MRI ischemic lesions compared with TFA. Other periprocedural outcomes were similar between the groups.

Nuances of transradial approach for mechanical thombectomy in acute basilar artery occlusion.

In elderly patients with acute ischemic stroke, tortuosity of the proximal vertebral artery makes access from the transfemoral route challenging and time consuming. In such cases, a transradial approach (TA) offers a more direct vertebral artery (VA) access that overcomes proximal VA tortuosity. In this video the authors illustrate nuances of the TA for acute basilar artery occlusion in two patients with challenging proximal VA anatomy. Techniques, devices, and pitfalls are discussed. In both patients, mechanical clot retrieval was successful and resulted in significant recovery of function. The authors believe that the TA should be the initial approach for basilar artery (BA) occlusion management in elderly patients and should be considered for selected patients with other conditions requiring endovascular treatment.The video can be found here: https://youtu.be/_Ym9tMKUy_4.

Nuances of transarterial and transvenous embolization of a large tentorial arteriovenous fistula.

An 80-year-old female presented with a long history of severe pulsatile tinnitus, vertigo, and decreased hearing. She was found to have a large right-sided tentorial arteriovenous fistula (AVF) with enlarged deep draining veins, including the vein of Rosenthal. The patient underwent Onyx embolization of the fistula via a combined transarterial and transvenous approach resulting in complete obliteration of the fistula. Her symptoms improved immediately after the procedure and at 6-months' follow-up she was clinically asymptomatic with no evidence of residual fistula on neuroimaging. Transvenous embolization of AVF is at times necessary when transarterial access is not possible.The video can be found here: https://youtu.be/uOMHY7eaOoQ.

Surgical treatment of previously embolized craniocervical junction dural arteriovenous fistula.

Craniocervical junction dural arteriovenous fistulas (dAVFs) are rare vascular lesions with a potentially dangerous natural history due to the onset of neurological deficit secondary to intracranial hemorrhage or myelopathy due to venous congestion. Despite advances in endovascular techniques, many dAVFs located in this area continue to require surgical treatment as embolization is often not feasible or safe. In this video, the authors illustrate a patient with a symptomatic craniocervical junction dAVF who had undergone attempted Onyx embolization at another institution. Because of persistent filling of the fistula and worsening myelopathy after the previous attempt, the patient was referred to the authors' clinic for definitive surgical treatment. The video illustrates the typical location of the early draining vein in most craniocervical junction dAVFs immediately below the emergence of the vertebral artery from the dura. The patient underwent successful definitive clip ligation of the fistula, which was exposed through a lateral suboccipital craniotomy.The video can be found here: https://youtu.be/Bvg6VKLgwO0.

Transvenous embolization of thalamic arteriovenous malformation under transient cardiac standstill.

Transvenous embolization (TE) has been increasingly applied for arteriovenous malformation (AVM) treatment. Transient cardiac standstill (TCS) has been described in cerebrovascular surgery but is uncommon for endovascular embolization. The authors present a patient with a ruptured thalamic AVM in whom both techniques were applied simultaneously. Surgery was considered, but the patient refused. Transarterial embolization was performed with an incomplete result. The deep-seated draining vein provided sole access to the AVM. A microcatheter was advanced into the draining vein. Under TCS, achieved with rapid ventricular pacing, complete AVM embolization was obtained. One-year magnetic resonance imaging and cerebral angiography demonstrated no residual AVM.The video can be found here: https://youtu.be/CAzb9md_xBU.

Effect of revascularization on cognitive outcomes in intracranial steno-occlusive disease: a systematic review.

OBJECTIVESteno-occlusive diseases of the cerebral vasculature have been associated with cognitive decline. The authors performed a systematic review of the existing literature on intracranial steno-occlusive disease, including intracranial atherosclerosis and moyamoya disease (MMD), to determine the extent and quality of evidence for the effect of revascularization on cognitive performance.METHODSA systematic search of PubMed/MEDLINE, the Thomson Reuters Web of Science Core Collection, and the KCI Korean Journal Database was performed to identify randomized controlled trials (RCTs) in the English-language literature and observational studies that compared cognitive outcomes before and after revascularization in patients with steno-occlusive disease of the intracranial vasculature, from which data were extracted and analyzed.RESULTSNine papers were included, consisting of 2 RCTs and 7 observational cohort studies. Results from 2 randomized trials including 142 patients with symptomatic intracranial atherosclerotic steno-occlusion found no additional benefit to revascularization when added to maximal medical therapy. The certainty in the results of these trials was limited by concerns for bias and indirectness. Results from 7 observational trials including 282 patients found some cognitive benefit for revascularization for symptomatic atherosclerotic steno-occlusion and for steno-occlusion related to MMD in children. The certainty of these conclusions was low to very low, due to both inherent limitations in observational studies for inferring causality and concerns for added risk of bias and indirectness in some studies.CONCLUSIONSThe effects of revascularization on cognitive performance in intracranial steno-occlusive disease remain uncertain due to limitations in existing studies. More well-designed randomized trials and observational studies are needed to determine if revascularization can arrest or reverse cognitive decline in these patients.

Transarterial embolization of an internal maxillary artery arteriovenous fistula presenting with pulsatile tinnitus.

Arteriovenous fistulae of the internal maxillary artery are exceedingly rare, with less than 30 cases reported in the literature. Most of these lesions are congenital, iatrogenic, or posttraumatic. The most common presentation of internal maxillary artery fistulae is pulsatile tinnitus and headache. Because these lesions are single-hole fistulae, they can be easily cured with endovascular techniques. The authors present a case of a patient who presented to their institution with a several-year history of pulsatile tinnitus who was found to have an internal maxillary artery arteriovenous fistula, which was treated endovascularly with transarterial coil and Onyx embolization.The video can be found here: https://youtu.be/fDZVMMwpwRc.

Nuances of carotid artery stenting under flow arrest with dual-balloon guide catheter.

Cerebral protection device utilization during carotid artery stenting (CAS) has been demonstrated to decrease the risk of perioperative stroke. The ProximAl Protection with the MO.MA Device During CaRotid Stenting (ARMOUR) Trial had the lowest event rates of any independently adjudicated study. In this video of two cases of severe carotid artery stenosis, the authors present the nuances of the CAS procedure utilizing a dual-balloon guide catheter device (MO.MA). This device has the benefit of being in place before the lesion is crossed with any device, being able to arrest flow while the atherosclerotic lesion is crossed, and aiding in protection from distal emboli and stroke.The video can be found here: https://youtu.be/0o8DlC1n6_M.

Novel rodent model for simulation of sylvian fissure dissection and cerebrovascular bypass under subarachnoid hemorrhage conditions: technical note and timing study.

OBJECTIVESylvian fissure dissection following subarachnoid hemorrhage (SAH) is a challenging but fundamental skill in microneurosurgery, and one that has become increasingly difficult to develop during residency, given the overarching management trends. The authors describe a novel rodent model for simulation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions.METHODSA standardized microvascular anastomosis model comprising rat femoral arteries and veins was used for the experimental framework. In the experimental protocol, following exposure and skeletonization of the vessels, extensive, superficial (1- to 2-mm) soft-tissue debridement was conducted and followed by wound closure and delayed reexploration at intervals of 7, 14, and 28 days. Two residents dissected 1 rat each per time point (n = 6 rats), completing vessel skeletonization followed by end-to-end artery/vein anastomoses. Videos were reviewed postprocedure to assess scar score and relative difficulty of dissection by blinded raters using 4-point Likert scales.RESULTSAt all time points, vessels were markedly invested in friable scar, and exposure was subjectively assessed as a reasonable surrogate for sylvian fissure dissection under SAH conditions. Scar score and relative difficulty of dissection both indicated 14 days as the most challenging time point.CONCLUSIONSThe authors' experimental model of femoral vessel skeletonization, circumferential superficial soft-tissue injury, and delayed reexploration provides a novel approximation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions. The optimal reexploration interval appears to be 7-14 days. To the authors' knowledge, this is the first model of SAH simulation for microsurgical training, particularly in a live animal system.

Endovascular delivery of leads and stentrodes and their applications to deep brain stimulation and neuromodulation: a review.

Neuromodulation and deep brain stimulation (DBS) have been increasingly used in many neurological ailments, including essential tremor, Parkinson's disease, epilepsy, and more. Yet for many patients and practitioners the desire to utilize these therapies is met with caution, given the need for craniotomy, lead insertion through brain parenchyma, and, at many times, bilateral invasive procedures. Currently endovascular therapy is a standard of care for emergency thrombectomy, aneurysm treatment, and other vascular malformation/occlusive disease of the cerebrum. Endovascular techniques and delivery catheters have advanced greatly in both their ability to safely reach remote brain locations and deliver devices. In this review the authors discuss minimally invasive endovascular delivery of devices and neural stimulating and recording from cortical and DBS targets via the neurovascular network.

Update on flow diverters for the endovascular management of cerebral aneurysms.

Flow diversion has become a well-accepted option for the treatment of cerebral aneurysms. Given the significant treatment effect of flow diverters, numerous options have emerged since the initial Pipeline embolization device studies. In this review, the authors describe the available flow diverters, both endoluminal and intrasaccular, addressing nuances of device design and function and presenting data on complications and outcomes, where available. They also discuss possible future directions of flow diversion.

Initial experience with a multiple parallel guidewire support system for complex tortuous aortic arch navigation and great vessel catheterization: technical note.

The ability to traverse an anatomically challenging and complex arch is paramount to the success of any neuroendovascular procedure. With age, the aortic arch becomes elongated, calcified, and less compliant. The authors present the initial experience with a multiple parallel guidewire system (ZigiWire Mode 3) for catheterization through a complex tortuous aortic arch to access extracranial vessels. The ZigiWire is an organized guidewire system that uses consecutive delivery of 3 small-diameter (0.014-inch) guidewires that are progressively advanced in parallel to secure support-wire access. The authors have found it useful in situations in which traditional methods for great-vessel access have failed. Moreover, the progressive construction of a large wire from smaller wires prevents "kickback" force from a single larger guidewire, allowing stable distal access. The authors have been able to advance different diagnostic and guide catheters over the ZigiWire. This guidewire has allowed them to successfully complete neuroendovascular procedures in patients who were previously considered unsuitable for the procedure because of tortuous vascular access.

Management of acute ischemic stroke due to tandem occlusion: should endovascular recanalization of the extracranial or intracranial occlusive lesion be done first?

OBJECTIVE Acute tandem occlusions of the cervical internal carotid artery and an intracranial large vessel present treatment challenges. Controversy exists regarding which lesion should be addressed first. The authors sought to evaluate the endovascular approach for revascularization of these lesions at Gates Vascular Institute. METHODS The authors performed a retrospective review of a prospectively maintained, single-institution database. They analyzed demographic, procedural, radiological, and clinical outcome data for patients who underwent endovascular treatment for tandem occlusions. A modified Rankin Scale (mRS) score ≤ 2 was defined as a favorable clinical outcome. RESULTS Forty-five patients were identified for inclusion in the study. The average age of these patients was 64 years; the mean National Institutes of Health Stroke Scale score at presentation was 14.4. Fifteen patients received intravenous thrombolysis before undergoing endovascular treatment. Thirty-seven (82%) of the 45 proximal cervical internal carotid artery occlusions were atherothrombotic in nature. Thirty-eight patients underwent a proximal-to-distal approach with carotid artery stenting first, followed by intracranial thrombectomy, whereas 7 patients underwent a distal-to-proximal approach (that is, intracranial thrombectomy was performed first). Thirty-seven (82%) procedures were completed with local anesthesia. For intracranial thrombectomy procedures, aspiration alone was used in 15 cases, stent retrieval alone was used in 5, and a combination of aspiration and stent-retriever thrombectomy was used in the remaining 25. The average time to revascularization was 81 minutes. Successful recanalization (thrombolysis in cerebral infarction Grade 2b/3) was achieved in 39 (87%) patients. Mean National Institutes of Health Stroke Scale scores were 9.3 immediately postprocedure (p < 0.05) (n = 31), 5.1 at discharge (p < 0.05) (n = 31), and 3.6 at 3 months (p < 0.05) (n = 30). There were 5 in-hospital deaths (11%); and 2 patients (4.4%) had symptomatic intracranial hemorrhage within 24 hours postprocedure. Favorable outcomes (mRS score ≤ 2) were achieved at 3 months in 22 (73.3%) of 30 patients available for follow-up, with an mRS score of 3 for 7 of 30 (23%) patients. CONCLUSIONS Tandem occlusions present treatment challenges, but high recanalization rates were possible in the present series using acute carotid artery stenting and mechanical thrombectomy concurrently. Proximal-to-distal and aspiration approaches were most commonly used because they were safe, efficacious, and feasible. Further study in the setting of a randomized controlled trial is needed to determine the best sequence for the treatment approach and the best technology for tandem occlusion.

Surgical management of skull base tumors.

AIM: To present a review of the contemporary surgical management of skull base tumors. BACKGROUND: Over the last two decades, the treatment of skull base tumors has evolved from observation, to partial resection combined with other therapy modalities, to gross total resection and no adjuvant treatment with good surgical results and excellent clinical outcomes. MATERIALS AND METHODS: The literature review of current surgical strategies and management of skull base tumors was performed and complemented with the experience of Barrow Neurological Institute. RESULTS: Skull base tumors include meningiomas, pituitary tumors, sellar/parasellar tumors, vestibular and trigeminal schwannomas, esthesioneuroblastomas, chordomas, chondrosarcomas, and metastases. Surgical approaches include the modified orbitozygomatic, pterional, middle fossa, retrosigmoid, far lateral craniotomy, midline suboccipital craniotomy, and a combination of these approaches. The selection of an appropriate surgical approach depends on the characteristics of the patient and the tumor, as well as the experience of the neurosurgeon. CONCLUSION: Modern microsurgical techniques, diagnostic imaging, intraoperative neuronavigation, and endoscopic technology have remarkably changed the concept of skull base surgery. These refinements have extended the boundaries of tumor resection with minimal morbidity.

Normal perfusion pressure breakthrough theory: a reappraisal after 35 years.

The intrinsic ability of the brain to maintain constant cerebral blood flow (CBF) is known as cerebral pressure autoregulation. This ability protects the brain against cerebral ischemia and hyperemia within a certain range of blood pressures. The normal perfusion pressure breakthrough (NPPB) theory described by Spetzler in 1978 was adopted to explain the edema and hemorrhage that sometimes occur after resection of brain arteriovenous malformations (AVMs). The underlying pathophysiology of edema and hemorrhage after AVM resection still remains controversial. Over the last three decades, advances in neuroimaging, CBF, and cerebral perfusion pressure (CPP) measurement have both favored and contradicted the NBBP theory. At the same time, other theories have been proposed, including the occlusive hyperemia theory. We believe that both theories are related and complementary and that they both explain changes in hemodynamics after AVM resection. The purpose of this work is to review the current status of the NBBP theory 35 years after its original description.

Update on transient cardiac standstill in cerebrovascular surgery.

Transient cardiac standstill is a complementary procedure used with microsurgery to treat patients with particularly complex aneurysms, such as large or giant cerebral aneurysms. These procedures allow the aneurysms to be decompressed while maintaining a bloodless field and increased surgical exposure. Deep hypothermia combined with circulatory arrest provides cerebroprotection with optimal surgical conditions. However, its disadvantage is the relatively high risk of the procedure, which requires extensive expertise and infrastructure. Thus, its use is typically limited to patients with complex posterior circulation aneurysms. Adenosine-induced transient asystole is an easily applied technique in a variety of clinical situations. Its use requires minimal advanced preparation and no complex logistical coordination with other subspecialties. However, patient-specific dose-response relationships must be determined by exposure, so the relationship may not be known in an emergent situation. Persistent hypotension is a potentially major complication. Rapid ventricular pacing (RVP) has recently been reintroduced into cerebrovascular surgery. It is more predictable than adenosine in response time and, thus, can be used during unanticipated complications, such as aneurysmal rupture. It also induces a shorter period of hypotension compared with adenosine. However, RVP is more invasive and more complex from an anesthesia standpoint. Vascular neurosurgeons should be familiar with these techniques and know their applications and limitations.

Microsurgical management of a large ICA bifurcation aneurysm.

A 70-year-old man with progressive visual disturbances, left superior quadrantanopsia, and right-sided papilledema underwent imaging that demonstrated a right internal carotid artery (ICA) terminus aneurysm with third-ventricle mass effect and ipsilateral optic nerve and chiasm compression. We performed a right modified orbitozygomatic craniotomy, with proximal control and dissection of the aneurysm and small perforator arteries. Temporary ICA and anterior cerebral artery (ACA) clips allowed placement of a large curved permanent clip, reconstructing the ICA bifurcation and maintaining adequate patency of the ACA and middle cerebral artery. Complete aneurysm obliteration was confirmed by intraoperative indocyanine green angiography and postoperative CT angiography. The video can be found here: http://youtu.be/5WEEgmA-g2A.

Microsurgical resection of cervical spinal arteriovenous malformation: the pial resection technique.

We present the case of a 26-year-old female patient who had two episodes of sudden, left, upper and lower extremity paresthesias and weakness, which resolved completely after 5 months. After recovery, she presented for evaluation. Imaging demonstrated a C3-C6 intra- and extra-axial arteriovenous malformation (AVM) with spinal cord compression and edema. A spinal angiogram showed arterial feeders arising from both vertebral arteries and from the right ascending pharyngeal artery. The AVM had been partially embolized after her first bleeding episode. She underwent C3-C6 laminoplasty and microsurgical resection of the AVM. After locating the main arterial feeders and draining veins, the malformation was resected using the pial resection technique. A postoperative spinal angiogram demonstrated gross total resection. Video used with permission from Barrow Neurological Institute. The video can be found here: http://youtu.be/JbbIwCTUsuI.