Radiation Exposure During Diagnostic and Therapeutic Angiography of Carotid-cavernous Fistula

Purpose The aim of this study was to determine local diagnostic reference levels (DRLs) during endovascular diagnostics and therapy of carotid-cavernous fistulas (CCF). Methods In a retrospective study design, DRLs, achievable dose (AD) and mean values were assessed for all patients with CCF undergoing diagnostic angiography (I) or embolization (II). All procedures were performed with the flat-panel angiography system Allura Xper (Philips Healthcare). Interventional procedures were differentiated according to the type of CCF and the type of procedure. Results In total, 86 neurointerventional procedures of 48 patients with CCF were executed between February 2010 and July 2021. The following DRLs, AD and mean values could be determined: (I) DRL 215 Gy ∙ cm2, AD 169 Gy ∙ cm2, mean 165 Gy ∙ cm2; (II) DRL 350 Gy ∙ cm2, AD 226 Gy ∙ cm2, mean 266 Gy ∙ cm2. Dose levels of embolization were significantly higher compared to diagnostic angiography (p < 0.001). No significant dose difference was observed with respect to the type of fistula or the embolization method. Conclusion This article reports on diagnostic and therapeutic DRLs in the management of CCF that could serve as a benchmark for the national radiation protection authorities. Differentiation by fistula type or embolization method does not seem to be useful.

Robotics in neurointerventional surgery: a systematic review of the literature

BackgroundRobotically performed neurointerventional surgery has the potential to reduce occupational hazards to staff, perform intervention with greater precision, and could be a viable solution for teleoperated neurointerventional procedures.ObjectiveTo determine the indication, robotic systems used, efficacy, safety, and the degree of manual assistance required for robotically performed neurointervention.MethodsWe conducted a systematic review of the literature up to, and including, articles published on April 12, 2021. Medline, PubMed, Embase, and Cochrane register databases were searched using medical subject heading terms to identify reports of robotically performed neurointervention, including diagnostic cerebral angiography and carotid artery intervention.ResultsA total of 8 articles treating 81 patients were included. Only one case report used a robotic system for intracranial intervention, the remaining indications being cerebral angiography and carotid artery intervention. Only one study performed a comparison of robotic and manual procedures. Across all studies, the technical success rate was 96% and the clinical success rate was 100%. All cases required a degree of manual assistance. No studies had clearly defined patient selection criteria, reference standards, or index tests, preventing meaningful statistical analysis.ConclusionsGiven the clinical success, it is plausible that robotically performed neurointerventional procedures will eventually benefit patients and reduce occupational hazards for staff; however, there is no high-level efficacy and safety evidence to support this assertion. Limitations of current robotic systems and the challenges that must be overcome to realize the potential for remote teleoperated neurointervention require further investigation.

Monitoring Radiation Doses during Diagnostic and Therapeutic Neurointerventional Procedures: Multicenter Study for Establishment of Reference Levels

Purpose: To assess patient radiation doses during diagnostic and therapeutic neurointerventional procedures from multiple centers and propose dose reference level (RL).Materials and Methods: Consecutive neurointerventional procedures, performed in 22 hospitals from December 2020 to June 2021, were retrospectively studied. We collected data from a sample of 429 diagnostic and 731 therapeutic procedures. Parameters including dose-area product (DAP), cumulative air kerma (CAK), fluoroscopic time (FT), and total number of image frames (NI) were obtained. RL were calculated as the 3rd quartiles of the distribution.Results: Analysis of 1160 procedures from 22 hospitals confirmed the large variability in patient dose for similar procedures. RLs in terms of DAP, CAK, FT, and NI were 101.6 Gy·cm², 711.3 mGy, 13.3 minutes, and 637 frames for cerebral angiography, 199.9 Gy·cm², 3,458.7 mGy, 57.3 minutes, and 1,000 frames for aneurysm coiling, 225.1 Gy·cm², 1,590 mGy, 44.7 minutes, and 800 frames for stroke thrombolysis, 412.3 Gy·cm², 4,447.8 mGy, 99.3 minutes, and 1,621.3 frames for arteriovenous malformation (AVM) embolization, respectively. For all procedures, the results were comparable to most of those already published. Statistical analysis showed male and presence of procedural complications were significant factors in aneurysmal coiling. Male, number of passages, and procedural combined technique were significant factors in stroke thrombolysis. In AVM embolization, a significantly higher radiation dose was found in the definitive endovascular cure group.Conclusion: Various RLs introduced in this study promote the optimization of patient doses in diagnostic and therapeutic interventional neuroradiology procedures. Proposed 3rd quartile DAP (Gy·cm²) values were 101.6 for diagnostic cerebral angiography, 199.9 for aneurysm coiling, 225.1 for stroke thrombolysis, and 412.3 for AVM embolization. Continual evolution of practices and technologies requires regular updates of RLs.

Penanganan Trigeminocardiac Reflex (TCR) selama Anestesi untuk Bedah Saraf

Trigeminocardiac reflex (TCR) is a unique brain stem reflex that manifests as negative cardio-respiratory perturbations. The trigeminocardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. Clinically, the TCR has been reported in all the surgical procedures in which a structure innervated by the trigeminal nerve is involved. This reflex is largely reported in skull base surgeries/interventions; however, in recent times, it has been also linked with many neurosurgical, neurointerventional procedures, non-neurosurgical and non-surgical conditions. This reflex presents with many cardiovascular changes that can create catastrophic complications, worse outcome as well as diagnostic dilemmas. Although, there is an abundant literature with reports of incidences and risk factors of the TCR; the physiological significance and function of this brainstem reflex has not yet been fully elucidated. In addition, there are complexities within the TCR that requires examination and clarification. If a CTR occurs, it can risk factor identification and modification, depth of anesthesia assessment, prophylactic treatment with either vagolytic agents or peripheral nerve block in case of peripheral manipulations of the nerve, careful cardiovascular monitoring during anesthesia, especially in those with a risk factor for TCR, treatment of the condition when it occurs: cessation of the manipulation, and administration of vagolytic agents and adrenaline. Therefore, this narrative review intends to elaborate on its mechanisms, definition, pathophysiology, manifestations, diagnosis and management.

Initial experience of subcutaneous nitroglycerin for distal transradial access in neurointerventions

Background: Transradial access (TRA) for diagnostic and interventional neuroendovascular procedures has gained significant popularity in recent years due to its improved safety profile and appeal to patients compared with transfemoral access. However, risks of TRA include hand ischemia in cases of poor ulnar collateral circulation and inability to cannulate the radial artery due to its relatively small diameter. By accessing the radial artery distal to the superficial palmar arch where ulnar collateral blood flow arises, in the anatomic snuffbox, the risk of hand ischemia is theoretically eliminated. The use of subcutaneous nitroglycerin and lidocaine to improve rates of success in radial artery access has been reported in the cardiac literature, however, has yet to be described for neurointerventional procedures. We discuss our technique and report our initial experience using subcutaneous nitroglycerin and lidocaine cocktail for access to the distal transradial artery in a variety of neuroendovascular procedures. Methods: A retrospective review of our institution’s database of neurointerventional and diagnostic procedures performed using dTRA was conducted, and 64 patients were identified between February and December 2020. Patient demographics, clinical data, procedural details, and radiographic information were collected and analyzed. Results: A total of 64 patients underwent neurointerventional procedures using the subcutaneous injection for dTRA access. The procedures performed included diagnostic cerebral angiograms (n = 47), stent and balloon assisted aneurysm coiling (n = 5), flow diversion (n = 2), intra-saccular device placement (n = 1), mechanical thrombectomy (n = 1), tumor embolization (n = 1), middle meningeal artery embolization (n = 2), extracranial carotid stent placement (n = 2), and arteriovenous malformation embolization (n = 3). While no complications of hand ischemia were appreciated, the access site conversion rate was 3.1%; 2 cases required a switch to femoral artery access due to proximal vessel tortuosity and aortic anatomical variations, and not due to access site complication. Furthermore, on repeat angiograms by the same proceduralist, distal TRA (dTRA) was successful in 100% of the cases. Conclusion: dTRA using subcutaneous nitroglycerin and lidocaine is a safe and effective method for neurointerventional and diagnostic procedures.

Direct carotid artery access for neurointerventional procedures in infants

BackgroundFemoral access is the primary route for neurointerventional procedures in children. However, endovascular treatment may not always be possible through a femoral approach, necessitating conversion to alternative access routes.ObjectiveTo review the feasibility and safety of direct carotid puncture (DCP) in infants undergoing neuroendovascular interventions.MethodsWe conducted a retrospective review of all infants who underwent DCP as the access route to treat neuroendovascular pathologies between January 2011 and January 2021. Patients’ demographics, clinical presentation, imaging findings, and technical details were reviewed.ResultsBetween January 2011 and January 2021, five infants aged between 28 and 150 days underwent DCP out of 1129 neuroendovascular interventions performed in our institution (0.4%). All five infants (100%) were diagnosed with intracranial fistulas and were found to have severe tortuosity of the cervical arteries. DCP was performed as the initial access route in 2/5 patients and as crossover after a failed femoral attempt in 3/5 patients. DCP was performed under ultrasound guidance in all patients. Closure was performed by manual compression, without complications. Ultrasound showed patent cervical vessels in all patients at 3 months’ follow-up.ConclusionDirect carotid access is a feasible and safe alternative route to treat neuroendovascular pathologies in infants and can be considered in cases of inaccessible or failed transfemoral access or in cases with severe arterial tortuosity in infants with intracranial fistulas.

Radial artery access anatomy: considerations for neuroendovascular procedures

Although enthusiasm for transradial access for neurointerventional procedures has grown, a unique set of considerations bear emphasis to preserve safety and minimize complications. In the first part of this review series, we will review important anatomical considerations for safe and easy neuroendovascular procedures from a transradial approach. These include normal and variant radial artery anatomy, the anatomic snuffbox, as well as axillary, brachial, and great vessel arterial anatomy that is imperative for the neuroendovascular surgeon to be intimately familiar prior to pursuing transradial access procedures. In the next part of the review series, we will focus on safety and complications specific to a transradial approach.

Radial artery access for neuroendovascular procedures: safety review and complications

Although enthusiasm for transradial access for neurointerventional procedures has grown, a unique set of considerations bear emphasis to preserve safety and minimize complications. In the first part of this review series, we reviewed anatomical considerations for safe and easy neuroendovascular procedures from a transradial approach. In this second part of the review series, we aim to (1) summarize evidence for safety of the transradial approach, and (2) explain complications and their management.

Aortic arch anomalies, embryology and their relevance in neuro-interventional surgery and stroke: A review

Background Congenital aortic arch anomalies are commonly encountered during neurointerventional procedures. While some anomalies are identified at an early age, many are incidentally discovered later in adulthood during endovascular evaluations or interventions. Proper understanding of the normal arch anatomy and its variants is pivotal to safely navigate normal aortic arch branches and to negotiate the catheter through anomalies during neurointerventional procedures. This is particularly relevant in the increasingly “transradial first” culture of neurointerventional surgery. Moreover, some of these anomalies have a peculiar predilection for complications including aneurysm formation, dissection, and rupture during the procedure. Therefore, an understanding of these anomalies, their underlying embryological basis and associations, and pattern of circulation will help endovascular neurosurgeons and interventional radiologists navigate with confidence and consider relevant pathologic associations that may inform risk of cerebrovascular disease. Methods Here, we present a brief review of the basic embryology of the common anomalies of the aortic arch along with their neurological significances and discuss, through illustrative cases, the association of aortic arch anomalies with cerebral vascular pathology. Conclusions Understanding the aortic arch anomalies and its embryological basis is essential to safely navigate the cerebral vascular system during neurointerventional surgeries.

Feasibility of robot-assisted neuroendovascular procedures

OBJECTIVE Geographic factors prevent equitable access to urgent advanced neuroendovascular treatments. Robotic technologies may enable remote endovascular procedures in the future. The authors performed a translational, benchtop-to-clinical study to evaluate the in vitro and clinical feasibility of the CorPath GRX Robotic System for robot-assisted endovascular neurointerventional procedures. METHODS A series of bench studies was conducted using patient-specific 3D-printed models to test the system’s compatibility with standard neurointerventional devices, including microcatheters, microwires, coils, intrasaccular devices, and stents. Optimal baseline setups for various procedures were determined. The models were further used to rehearse clinical cases. Subsequent to these investigations, a prospective series of 6 patients was treated using robotic assistance for complex, wide-necked intracranial saccular aneurysms between November 2019 and February 2020. The technical success, incidence of periprocedural complications, and need for conversion to manual procedures were evaluated. RESULTS The ideal robotic setup for treatment of both anterior and posterior circulation aneurysms was determined to consist of an 80-cm guide catheter with a 115-cm-long intermediate catheter, a microcatheter between 150 and 170 cm in length, and a microwire with a minimum length of 300 cm. All coils, intrasaccular devices, and stents tested were compatible with the system and could be advanced or retracted safely and placed accurately. All 6 clinical procedures were technically successful, with all intracranial steps being performed robotically with no conversions to manual intervention or failures of the robotic system. There were no procedure-related complications or adverse clinical outcomes. CONCLUSIONS This study demonstrates the feasibility of robot-assisted neurointerventional procedures. The authors’ results represent an important step toward enabling remote neuroendovascular care and geographic equalization of advanced endovascular treatments through so-called telestroke intervention.