Giant Pediatric Dural Arteriovenous Fistula Management Using a Combined Operative Approach in a Hybrid Neuroendovascular Surgery Suite: Technical Nuances and Review of Literature.

BACKGROUND: Pediatric intracranial dural arteriovenous fistulas (dAVFs) are rare, complex entities usually presenting with macrocephaly from increased intracranial pressures at a young age. In the setting of a symptomatic intracranial dAVF that has undergone multiple endovascular treatments with subsequent recurrence or failed embolization attempts, the intracranial venous system can become inaccessible by traditional transvenous and transarterial routes. Direct puncture of the venous sinus for endovascular access after surgical exposure is a viable option. OBJECTIVE: To describe the technical nuances and available literature for direct puncture of the venous sinus for endovascular access in a pediatric patient with dAVF. METHODS: The clinical characteristics were reviewed and reported for a patient who underwent direct puncture of the venous sinus for endovascular access. In addition, a literature review was conducted for relevant literature pertaining to this technique and its associated indications, outcomes, and complications. RESULTS: Only 2 other reports of direct puncture of venous sinus for endovascular access after surgical exposure were found in the literature. Our patient achieved a favorable outcome with complete dAVF obliteration. CONCLUSION: Direct puncture of the venous sinus for endovascular access after surgical exposure for complex dAVFs that are inaccessible by transvenous or transarterial routes is a practical and safe approach to intracranial venous access that should be part of the vascular neurosurgeon's arsenal.

Angiographic Evaluation of Cranial Venous Outflow Patterns in Patients With and Without Idiopathic Intracranial Hypertension.

BACKGROUND: Several collateral venous pathways exist to assist in cranial venous drainage in addition to the internal jugular veins. The important extrajugular networks (EJN) are often readily identified on diagnostic cerebral angiography. However, the angiographic pattern of venous drainage through collateral EJN has not been previously compared among patients with and without idiopathic intracranial hypertension (IIH). OBJECTIVE: To quantify EJN on cerebral angiography among patients both with and without IIH and to determine whether there is a different EJN venous drainage pattern in patients with IIH. METHODS: Retrospective imaging review of 100 cerebral angiograms (50 IIH and 50 non-IIH patients) and medical records from a single academic medical center was performed by 2 independent experienced neuroendovascular surgeons. Points were assigned to EJN flow from 0 to 6 using an increasing scale (with each patient's dominant internal jugular vein standardized to 5 points to serve as the internal reference). Angiography of each patient included 11 separately graded extrajugular networks for internal carotid and vertebral artery injections. RESULTS: Patients in the IIH group had statistically significant greater flow in several of the extrajugular networks. Therefore, they preferentially drained through EJN compared with the non-IIH group. Right transverse-sigmoid system was most often dominant in both groups, yet there was a significantly greater prevalence of codominant sinus pattern on posterior circulation angiograms. CONCLUSION: Patients with IIH have greater utilization of EJN compared with patients without IIH. Whether this is merely an epiphenomenon or possesses actual cause-effect relationships needs to be determined with further studies.

Superior sagittal sinus-to-internal jugular vein bypass shunt with covered stent construct for intractable intracranial hypertension resulting from iatrogenic supratorcular sinus occlusion: technical note.

BACKGROUND: Acute occlusion of the posterior sagittal sinus may lead to dramatic increase in intracranial pressure (ICP), refractory to standard treatment. Hybrid vascular bypass of cranial venous outflow into the internal jugular vein (IJV) has seldom been described for this in recent neurosurgical literature. OBJECTIVE: To describe creation of a novel vascular bypass shunt from the superior sagittal sinus (SSS) to internal jugular vein (IJV) utilizing a covered stent-Dacron graft construct for control of refractory ICP. METHODS: We illustrate a patient with refractory ICP increases after acute sinus ligation that was performed to halt torrential bleeding from intraoperative injury. A temporary shunt was created that successfully controlled ICP. From the promising results of the temporary shunt, we utilized a prosthetic hybrid bypass graft to function as a shunt from the sagittal sinus to IJV. Yet the associated anticoagulation led to complications and a poor outcome. RESULTS: Rapid and sustained ICP reduction can be expected after sagittal sinus-to-jugular bypass shunt placement in acute sinus occlusion. Details of the surgical technique are described. Heparin anticoagulation, while imperative, is also associated with worrisome complications. CONCLUSION: Acute occlusion of posterior third of sagittal sinus carries a very malignant clinical course. Intractable intracranial hypertension from acute sinus occlusion may be effectively treated with a SSS-IJV bypass shunt. A covered stent construct provides an effective vascular bypass conduit. However, the anticoagulation risk can lead to fatal outcomes. The neurosurgeon must always strive for primary repair of an injured sinus.

Upper extremity transvenous access for neuroendovascular procedures: an international multicenter case series.

BACKGROUND: Radial artery access for transarterial procedures has gained recent traction in neurointerventional due to decreased patient morbidity, technical feasibility, and improved patient satisfaction. Upper extremity transvenous access (UETV) has recently emerged as an alternative strategy for the neurointerventionalist, but data are limited. Our objective was to quantify the use of UETV access in neurointerventions and to measure failure and complication rates. METHODS: An international multicenter retrospective review of medical records for patients undergoing UETV neurointerventions or diagnostic procedures was performed. We also present our institutional protocol for obtaining UETV and review the existing literature. RESULTS: One hundred and thirteen patients underwent a total of 147 attempted UETV procedures at 13 centers. The most common site of entry was the right basilic vein. There were 21 repeat puncture events into the same vein following the primary diagnostic procedure for secondary interventional procedures without difficulty. There were two minor complications (1.4%) and five failures (ie, conversion to femoral vein access) (3.4%). CONCLUSIONS: UETV is safe and technically feasible for diagnostic and neurointerventional procedures. Further studies are needed to determine the benefit over alternative venous access sites and the effect on patient satisfaction.

Delayed chemical meningitis after Chiari decompression with duraplasty: illustrative cases.

BACKGROUND: Dural reconstruction to achieve expansion duraplasty is important in suboccipital decompression for Chiari malformation type 1 (CM1). Although various dural substitutes are available, including synthetic collagen matrix grafts and dural xenografts, they have the potential to induce an inflammatory response. In this case series, the authors present their experience and discuss the incidence and possible mechanism of aseptic meningitis after the use of bovine collagen matrix graft as a dural substitute in patients with CM1 after suboccipital decompression. OBSERVATIONS: Three consecutive adult female patients who underwent suboccipital decompression at a single institution by a single neurosurgeon were retrospectively reviewed. They all presented with signs of aseptic meningitis in a delayed fashion, responded well to steroid administration, but had recurrence of their symptoms. Bovine collagen dural substitutes are resorbed in a process that induces an inflammatory response manifesting with signs of aseptic meningitis and is only alleviated with removal of the dural substitute. LESSONS: DuraMatrix Suturable, a dural xenograft derived from bovine dermis, though a viable choice for dural repair, is a potential cause of chemical meningitis after duraplasty in Chiari decompression surgery. In patients presenting with delayed and persistent aseptic meningitis after intervention, removal of this dural substitute led to improved symptomatology.

Illustrated Guide to the Transradial Approach for Neuroendovascular Surgery: A Step-by-Step Description Gleaned From Over 500 Cases at an Early Adopter Single Center.

BACKGROUND: Traditionally, neuroangiography for diagnosis and therapy has been achieved via the transfemoral route. Femoral access, however, has been associated with catastrophic complications. Although transradial access (TRA) has been adopted late by the field of neuroendovascular surgery, several groups have recently demonstrated a dramatically safe and rapid learning curve with a radial-first approach. However, there is a need for a detailed illustrative approach on the transradial technique. OBJECTIVE: To provide a detailed description of the operative technique with step-by-step illustrations derived from our single center series of 506 cases, as an early adopter. METHODS: A step-by-step illustrated approach to our technique of transradial angiography is provided, based on our clinical experience of an early radial-first approach. Prospective review of patients undergoing transradial angiography and interventions from April 1 to November 30, 2019, at our institution was performed. We included all cases that received radial-first arterial access for diagnostic and interventional neuroangiography. Efficacy, complications, catheter use, and radiation metrics of TRA for the entire cohort were noted. The radial approach was described in 4 stages beginning from the wrist (Stage I) and ending with distal access to target vessel of interest (Stage IV). RESULTS: A total of 506 patients underwent TRA over the 7-mo period. Procedural success was achieved in 92.3% of patients (93.7% for diagnostic and 88.5% for interventional). Crossover to the femoral route occurred in 33 (6.5%) cases (25 diagnostic and 8 interventional). The majority occurred in Stage I. No major complications were noted. CONCLUSION: Our preferred technique for the transradial approach provides excellent safety and efficacy in performing diagnostic and interventional neuroangiography. The illustrated technical steps are expected to provide guidance for early adopters of TRA.

Incorporation of transradial approach in neuroendovascular procedures: defining benchmarks for rates of complications and conversion to femoral access.

BACKGROUND: The transradial approach (TRA) has gained increasing popularity for neuroendovascular procedures. However, the experience with TRA in neuroangiography is still in early stages in most centers, and the safety and feasibility of this approach have not been well established. The purpose of this study is to report the safety and feasibility of TRA for neuroendovascular procedures. METHODS: We reviewed charts from six institutions in the USA to include consecutive patients who underwent diagnostic or interventional neuroendovascular procedures through TRA from July 2018 to July 2019. Collected data included baseline characteristics, procedural variables, complications, and whether there was a crossover to transfemoral access. RESULTS: A total of 2203 patients were included in the study (age 56.1±15.2, 60.8% women). Of these, 1697 (77%) patients underwent diagnostic procedures and 506 (23%) underwent interventional procedures. Successfully completed procedures included aneurysm coiling (n=97), flow diversion (n=89), stent-assisted coiling (n=57), balloon-assisted coiling (n=19), and stroke thrombectomy (n=76). Crossover to femoral access was required in 114 (5.2%). There were no major complications related to the radial access site. Minor complications related to access site were seen in 14 (0.6%) patients. CONCLUSION: In this early stage of transforming to the 'radial-first' approach for neuroendovascular procedures, TRA was safe with low complication rates for both diagnostic and interventional procedures. A wide range of procedures were completed successfully using TRA.

Extended Lateral Orbital Craniotomy: Anatomic Study and Initial Clinical Series of a Novel Minimally Invasive Pterional Approach.

Background Of the minimally invasive "keyhole" alternatives to the pterional region, the supraorbital eyebrow approach is the most widely adopted. Yet it can prove disadvantageous when a more direct lateral microsurgical trajectory of attack to the Sylvian fissure and anterior middle fossa are needed. Objective The extended lateral orbital (XLO) approach was designed to be direct and minimally invasive, with the sphenoid ridge at the center of exposure. Methods Five injected cadaver heads were used for anatomic study of the XLO approach. The anatomic course of the frontalis branch of facial nerve was studied in relation to the XLO incision. Following XLO incision, the bone exposure was measured. The intracranial microsurgical exposure was assessed subjectively. Application of the technique in representative clinical operative cases is provided. Results The frontalis nerve was protected in the subgaleal fat pad, with an average minimum distance of 2.3 cm from the XLO incision. The mean calvarial area exposure was 4.95 cm 2 and consistently centered on the sphenoid ridge. Excellent access to ipsilateral Sylvian's fissure, perisylvian regions, and supra-/parasellar structures was possible. The main limitations related to exposure of the posterior Sylvian fissure and the expected limitations of microsurgical instrument manipulation from a smaller craniotomy. Conclusions The XLO approach is a minimally invasive keyhole approach to the pterional region that affords a unique lateral trajectory via a craniotomy centered on the sphenoid ridge. Excellent exposure to properly selected lesions is possible. The incision is at a safe distance from the frontalis branch and shows excellent cosmetic healing.

Fast-track incorporation of the transradial approach in endovascular neurointervention.

BACKGROUND: The transradial approach as a frontline approach is a novel technique in neuroendovascular procedures. In this study we aim to present our early experience with full transition to transradial access as the first-line approach for neuroendovascular procedures. METHODS: We prospectively collected data on the first 100 consecutive patients who underwent a diagnostic or interventional neuroendovascular procedure using the transradial approach at our institution between March 22 and April 30, 2019. Baseline characteristics were collected in addition to the type of procedure, access site, catheters and wires used, complications, and whether there was crossover to transfemoral access. RESULTS: Transradial access was attempted in 121 cases and 91 cases were completed successfully (72 diagnostic procedures and 19 interventional procedures). Mean (SD) age was 56.8 (14.7) years, 54.9% (50/91) underwent the procedure in the outpatient setting, and 60.4% (55/91) were women. Seven patients had minor immediate complications related to the radial access. Interventional procedures successfully performed included aneurysm embolization (ruptured (n=3) and unruptured (n=8)), tumor embolization (n=2), cervical internal carotid artery stenting (n=2), balloon occlusion test (n=1), vertebral artery sacrifice (n=1), and arteriovenous malformation embolization (n=2). CONCLUSION: In this early experience, full transition to the transradial approach as the frontline approach is feasible with a low complication rate for both diagnostic and interventional neuroendovascular procedures.

Anomalous "Middle" Meningeal Artery from Basilar Artery and Implications for Neuroendovascular Surgery: Case Report and Review of Literature.

BACKGROUND: The middle meningeal artery (MMA) is an important conduit for the endovascular treatment of skull base and intracranial pathologies including, recently, subdural hematomas. A key aspect of such procedures is to perform a thorough diagnostic angiogram to detect anomalous arterial origins and "dangerous" anastomoses with branches of the internal carotid arteries. Although the most common anomaly related to the MMA is an abnormal origin from the ophthalmic artery, anomalous origin from the posterior circulation is rare. Moreover, its recognition requires a concerted effort at performing a vertebral artery angiogram irrespective of the location of the pathology (e.g., in subdural hematoma). CASE DESCRIPTION: We describe a case of anomalous origin of MMA from the basilar artery as a lateral pontine artery branch that was detected in a patient with recurrent subdural hematoma who presented for endovascular MMA embolization. CONCLUSIONS: The embryologic origin of the entity is briefly discussed, along with suggestions for managing such an anomaly during endovascular embolization.

Treatment Strategy of a Patient With a Brain Arteriovenous Malformation and Cranial Dural Fistula: 2-Dimensional Operative Video.

We present the case of a 56-yr-old right-handed male, after informed consent was obtained, who presented with acute confusion and agitation, on the background of a remote history of an uncomplicated resection of a left parietal grade 2 glioma. Imaging revealed a large, acute right temporal intracerebral hemorrhage (ICH). Standard vascular workup for the cause of the ICH included catheter angiography. No direct cause of the hemorrhage was revealed; however, a high grade parasagittal dural arteriovenous fistula (DAVF) with cortical venous reflux was noted close to the prior craniotomy site. The venous reflux was towards the left hemisphere, but it was hypothesized that similar reflux on the right side may have been present and was not presently evident due to thrombosis. The DAVF was embolized by endovascular means, followed by evacuation of the hematoma. Follow-up angiogram 7 mo later revealed a high-flow, right superior temporal cortical arteriovenous malformation (AVM). The DAVF unfortunately had also progressed. Endovascular occlusion of both lesions was attempted but was not successful. Subsequently, microsurgical resection for both the vascular malformations was performed with careful pre- and intraoperative planning to obtain a successful clinical and angiographic result. In this video, we summarize diagnostic and therapeutic nuances that have broad implications for the workup of ICH and the strategic management of a unique scenario involving a brain AVM and high-grade cranial dural fistula in the same patient. Prior to each procedure, informed consent was obtained from the patient, which includes consent for publication.

Hemicraniectomy for Ischemic and Hemorrhagic Stroke: Facts and Controversies.

Malignant large artery stroke is associated with high mortality of 70% to 80% with best medical management. Decompressive craniectomy (DC) is a highly effective tool in reducing mortality. Convincing evidence has accumulated from several randomized trials, in addition to multiple retrospective studies, that demonstrate not only survival benefit but also improved functional outcome with DC in appropriately selected patients. This article explores in detail the evidence for DC, nuances regarding patient selection, and applicability of DC for supratentorial intracerebral hemorrhage and posterior fossa ischemic and hemorrhagic stroke.

Awake Surgery for Brain Vascular Malformations and Moyamoya Disease.

OBJECTIVE: Although a significant amount of experience has accumulated for awake procedures for brain tumor, epilepsy, and carotid surgery, its utility for intracranial neurovascular indications remains largely undefined. Awake surgery for select neurovascular cases offers the advantage of precise brain mapping and robust neurologic monitoring during surgery for lesions in eloquent areas, avoidance of potential hemodynamic instability, and possible faster recovery. It also opens the window for perilesional epileptogenic tissue resection with potentially less risk for iatrogenic injury. METHODS: Institutional review board approval was obtained for a retrospective review of awake surgeries for intracranial neurovascular indications over the past 36 months from a prospectively maintained quality database. We reviewed patients' clinical indications, clinical and imaging parameters, and postoperative outcomes. RESULTS: Eight consecutive patients underwent 9 intracranial neurovascular awake procedures conducted by the senior author. A standardized "sedated-awake-sedated" protocol was used in all 8 patients. For the 2 patients with arteriovenous malformations and the 3 patients with cavernoma, awake brain surface and white matter mapping was performed before and during microsurgical resection. A neurological examination was obtained periodically throughout all 5 procedures. There were no intraoperative or perioperative complications. Hypotension was avoided during the 2 Moyamoya revascularization procedures in the patient with a history of labile blood pressure. Postoperative imaging confirmed complete arteriovenous malformation and cavernoma resections. No new neurologic deficits or new-onset seizures were noted on 3-month follow-up. CONCLUSIONS: Awake surgery appears to be safe for select patients with intracranial neurovascular pathologies. Potential advantages include greater safety, shorter length of stay, and reduced cost.

Remote supratentorial extradural hematoma following posterior fossa surgery.

INTRODUCTION: Posterior fossa tumors are associated frequently with hydrocephalus. Remote supratentorial hematoma after posterior fossa surgery is a rare but dreaded complication. DISCUSSION: These hematomas can be intraparenchymal or extradural. The possible causes include sudden decompression of ventricular pressure in the supratentorial compartment, rupture of cortical veins in the sitting position, coagulopathy, hemodynamic fluctuations during surgery, and position-related ischemia. We report a large bifrontal extradural hematoma following posterior fossa surgery for a vermian medulloblastoma.