Can exoscope improve brain AVMs surgery?

The advantages of the surgical view provided by the exoscope have been described before, although reports of its application to brain arteriovenous malformation (AVM) surgery are lacking. The ampler field of view and magnification up to ×24 allow for enhanced visualization during microsurgical procedures. Furthermore, the live visualization provided by indocyanine green video angiography (ICG-VA) helps emphasize the hemodynamics of AVMs, even allowing the detection of possible residual vein arterialization as an indirect expression of nidal remnants. With this illustrative video showing the resection of a hemorrhagic right frontoinsular Spetzler-Martin grade III AVM, the authors describe the technical implications of exoscope brain AVM surgery using the Olympus ORBEYE 4K-3D, with a final focus on ICG-VA as an asset. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23114.

Ultrahigh-Definition-3-Dimensional Exoscope-Assisted Clipping of a Right Middle Cerebral Artery Unruptured Aneurysm with Indocyanine Green Video Angiography: Operative Video.

Ultrahigh-definition 3-dimensional exoscopes represent an excellent technologic innovation in contemporary neurosurgery. They combine the advantages of operating microscopes and endoscopes, offering excellent magnification and lighting, maintaining a relatively small footprint and optimal ergonomic features.1-5 One of the most interesting employments of exoscopes in neurosurgery is represented by intracranial vascular surgery. Reports in this field are still limited, but recent experience has shown that ultrahigh definition 3-dimensional exoscopes for aneurysm surgery are noninferior to operating microscopes for surgery duration, complication rate, and patient outcomes.6 In addition, many intraoperative techniques such as the indocyanine green videoangiography (ICG-VA) have been successfully implemented to exoscope-based surgery.7 We present herein the case of a 66-year-old woman that came to our attention for the incidental finding of 3 unruptured brain aneurysms. After neurosurgical consultation, the one located at the right middle cerebral artery bifurcation was considered eligible for surgery.8,9 As shown in Video 1, ICG-VA was employed after permanent clipping to allow immediate quality assurance of occlusion and distal vessel integrity. Postoperative course was uneventful, and follow-up examinations demonstrated the complete occlusion of the aneurysm. This report highlights the feasibility of exoscopic-based ICG-VA in vascular neurosurgery, given its ease of use, ergonomics, and excellent quality of vision provided to both surgeons and operating staff.

Utility of indocyanine green videoangiography with FLOW 800 analysis in brain tumour resection as a venous protection technique.

BACKGROUND: In regard to central nervous system tumour resection, preserving vital venous structures to avoid devastating consequences such as brain oedema and haemorrhage is important. However, in clinical practice, it is difficult to obtain clear and vivid intraoperative venous visualization and blood flow analyses. METHODS: We retrospectively reviewed patients who underwent brain tumour resection with the application of indocyanine green videoangiography (ICG-VA) integrated with FLOW 800 from February 2019 to December 2020 and present our clinical cases to demonstrate the process of venous preservation. Galen, sylvian and superior cerebral veins were included in these cases. RESULTS: Clear documentation of the veins from different venous groups was obtained via ICG-VA integrated with FLOW 800, which semiquantitatively analysed the flow dynamics. ICG-VA integrated with FLOW 800 enabled us to achieve brain tumour resection without venous injury or obstruction of venous flux. CONCLUSIONS: ICG-VA integrated with FLOW 800 is an available method for venous preservation, although further comparisons between ICG-VA integrated with FLOW 800 and other techniques of intraoperative blood flow monitoring is needed.

Intraoperative indocyanine green video angiography (ICG-VA) with FLOW 800 software in complex intracranial aneurysm surgery.

BACKGROUND: Indocyanine green video angiography (ICG-VA) is a safe and effective instrument to assess changes in cerebral blood flow during cerebrovascular surgery. After ICG-VA, FLOW 800 provides a color-coded map to directly observe the dynamic distribution of blood flow and to calculate semiquantitative blood flow parameters later. The purpose of our study is to assess whether FLOW 800 is useful for surgery of complex intracranial aneurysms and to provide reliable evidence for intraoperative decision-making. METHODS: We retrospectively reviewed patients with complex aneurysms that underwent microsurgical and intraoperative evaluation of ICG-VA and FLOW 800 color-coded maps from February 2019 to May 2020. FLOW 800 data were correlated with patient characteristics, clinical outcomes, and intraoperative decision-making. RESULTS: The study included 32 patients with 42 complex aneurysms. All patients underwent ICG-VA FLOW 800 data provided semiquantitative data regarding localization, flow status in major feeding arteries; color maps confirmed relative adequate flow in parent, branching, and bypass vessels. CONCLUSIONS: FLOW 800 is a useful supplement to ICG-VA for intraoperative cerebral blood flow assessment. ICG-VA and FLOW 800 can help to determine the blood flow status of the parent artery after aneurysm clipping and the bypass vessels after aneurysm bypass surgery.

First-in-Human Clinical Experience Using High-Definition Exoscope with Intraoperative Indocyanine Green for Clip Reconstruction of Unruptured Large Pediatric Aneurysm.

The operative exoscope is a novel tool that combines the benefits of surgical microscopes and endoscopes to yield excellent magnification and illumination while maintaining a comparatively small footprint and superior ergonomic features. Until recently, current exoscopes have been limited by 2-dimensional viewing; however, recently a 3-dimensional (3D), high-definition (4K-HD) exoscope has been developed (Sony-Olympus, Tokyo, Japan).1 Our group had previously described the first in-human experiences with this novel tool including microsurgical clipping of intracranial aneurysms. We have highlighted the benefits of the exoscope, which include providing an immersive experience for surgeons and trainees, as well as superior ergonomics as compared with traditional microsurgery.2 To date, exoscopic 3D high-definition indocyanine green (ICG) video angiography (ICG-VA) has not been described. ICG-VA, now a mainstay of vascular microsurgery, uses intravenously injected dye to visualize intravascular fluorescence in real time to assess the patency of arteries and assess clip occlusion of aneurysms.3,4 The ability to safely couple this tool with the novel exoscope has the potential to advance cerebrovascular microsurgery. Here, we present a case of a 11-year-old male with Alagille syndrome, pancytopenia, and peripheral pulmonary stenosis found to have a 12 × 13 × 7 mm distal left M1 aneurysm arising from the inferior M1/M2 junction. The patient was neurologically intact without evidence of rupture. In order to prevent catastrophic rupture, the decision was made to treat the lesion. Due to the patients underlying medical conditions including baseline coagulopathy, surgical management was felt to be superior to an endovascular reconstruction, which would require long-term antiplatelet therapy. Thus the patient underwent a left-sided pterional craniotomy with exoscopic 3D ICG-VA. As demonstrated in Video 1, ICG-VA was performed before definitive clip placement in order to understand flow dynamics with particular emphasis on understanding the middle cerebral artery outflow. Postoperatively, the patient remained at his neurologic baseline and subsequent imaging demonstrated complete obliteration of the aneurysm without any neck remnant. The patient continues to follow and remains asymptomatic and neurologically intact without radiographic evidence of residual or recurrence.

Novel Software-Derived Workflow in Extracranial-Intracranial Bypass Surgery Validated by Transdural Indocyanine Green Videoangiography.

BACKGROUND: The introduction of image-guided methods to bypass surgery has resulted in optimized preoperative identification of the recipients and excellent patency rates. However, the recently presented methods have also been resource-consuming. In the present study, we have reported a cost-efficient planning workflow for extracranial-intracranial (EC-IC) revascularization combined with transdural indocyanine green videoangiography (tICG-VA). METHODS: We performed a retrospective review at a single tertiary referral center from 2011 to 2018. A novel software-derived workflow was applied for 25 of 92 bypass procedures during the study period. The precision and accuracy were assessed using tICG-VA identification of the cortical recipients and a comparison of the virtual and actual data. The data from a control group of 25 traditionally planned procedures were also matched. RESULTS: The intraoperative transfer time of the calculated coordinates averaged 0.8 minute (range, 0.4-1.9 minutes). The definitive recipients matched the targeted branches in 80%, and a neighboring branch was used in 16%. Our workflow led to a significant craniotomy size reduction in the study group compared with that in the control group (P = 0.005). tICG-VA was successfully applied in 19 cases. An average of 2 potential recipient arteries were identified transdurally, resulting in tailored durotomy and 3 craniotomy adjustments. Follow-up patency results were available for 49 bypass surgeries, comprising 54 grafts. The overall patency rate was 91% at a median follow-up period of 26 months. No significant difference was found in the patency rate between the study and control groups (P = 0.317). CONCLUSIONS: Our clinical results have validated the presented planning and surgical workflow and support the routine implementation of tICG-VA for recipient identification before durotomy.

Indocyanine green fluorescence video angiography reduces vascular injury-related morbidity during micro-neurosurgical clipping of ruptured cerebral aneurysms: a retrospective observational study.

BACKGROUND: Specific procedural complications in aneurysm surgery are broadly related to vascular territory compromise and brain/nerve retraction; vascular complications account for about half of this. Intraoperative indocyanine green video angiography (ICG-VA) provides real-time high spatial resolution imaging of the cerebrovascular architecture, allowing immediate quality assurance of aneurysm occlusion and vessel integrity. The aim of this study was to examine whether the routine use of ICG-VA reduced early procedural complications related to vascular compromise or injury during micro-neurosurgical clipping of ruptured cerebral aneurysms. METHODS: Retrospective comparative observational study of 412 adult good-grade (WFNS 1 or 2) SAH patients who had undergone microsurgical clipping without (n = 200, 2001-2004) or with (n = 212, 2009-2015) ICG-VA in a high-volume neurosurgical centre. RESULTS: The ICG-VA group had a significantly lower incidence of procedural vascular complications (7/212; 3.3%) compared with the non-ICG-VA group (19/200; 9.5%) (Fisher's exact test p = 0.0137). CONCLUSIONS: ICG-VA is a straightforward, easy-to-use, intraoperative adjunct which significantly reduces avoidable 'technical error' related morbidity.

Endoscope- versus microscope-integrated near-infrared indocyanine green videoangiography in aneurysm surgery.

OBJECTIVE: The quality of surgical treatment of intracranial aneurysms is determined by complete aneurysm occlusion while preserving blood flow in the parent, branching, and perforating arteries. For a few years, there has been a nearly noninvasive and cost-effective technique for intraoperative flow evaluation: microscope-integrated indocyanine green videoangiography (mICG-VA). This method allows for real-time information about blood flow in the aneurysm and the involved vessels, but its limitations are seen in the evaluation of structures located in the depth of the surgical field, especially through small craniotomies. To compensate for these drawbacks, an endoscope-integrated ICG-VA (eICG-VA) was developed. The objective of the present study was to assess the use of eICG-VA in comparison with mICG-VA for intraoperative blood flow evaluation. METHODS: In the period between January 2011 and January 2015, 216 patients with a total of 248 intracranial saccular aneurysms were surgically treated in the Department of Neurosurgery of Saarland University Medical Center in Homburg/Saar, Germany. During 95 surgeries in 88 patients with a total of 108 aneurysms, intraoperative evaluation was performed with both eICG-VA and mICG-VA. After clipping, evaluation of complete aneurysm occlusion and flow in the parent, branching, and perforating arteries was performed using both methods. Intraoperative applicability of each technique was compared with the other and with postoperative digital subtraction angiography as a standard evaluation technique. RESULTS: Evaluation of completeness of aneurysm occlusion and of flow in the parent, branching, and perforating arteries was more successful with eICG-VA than with mICG-VA, especially for aneurysm neck assessment (88.9% vs 69.4%). For 63.9% of the aneurysms (n = 69), both methods were equivalent, but in 30.6% of the cases (n = 33), the eICG-VA provided better results for evaluating the post-clipping situation. In 4.6% of these aneurysms (n = 5), the information given by the additional endoscope considerably changed the surgical procedure. Thus, one residual aneurysm (0.9%), two neck remnants (1.9%), and two branch occlusions (1.9%) could be prevented. Nevertheless, two incomplete aneurysm occlusions (1.9%) and six neck remnants (5.6%) were revealed by postoperative digital subtraction angiography. CONCLUSIONS: Endoscope-integrated ICG-VA seems to be an improvement that might increase the quality of aneurysm surgery by providing additional information. It offers higher illumination, magnification, and an extended viewing angle. Its main advantage is its ability to assess deep-seated aneurysms, especially through small craniotomies, but further studies are required.

Use of ICG videoangiography and FLOW 800 analysis to identify the patient-specific venous circulation and predict the effect of venous sacrifice: a retrospective study of 172 patients.

OBJECTIVE The best management of veins encountered during the neurosurgical approach is still a matter of debate. Even if venous sacrifice were to lead to devastating consequences, under certain circumstances, it might prove to be desirable, enlarging the surgical field or increasing the extent of resection in tumor surgery. In this study, the authors present a large series of patients with vascular or oncological entities, in which they used indocyanine green videoangiography (ICG-VA) with FLOW 800 analysis to study the patient-specific venous flow characteristics and the management workflow in cases in which a venous sacrifice was necessary. METHODS Between May 2011 and December 2017, 1972 patients were admitted to the authors' division for tumor and/or neurovascular surgery. They retrospectively reviewed all cases in which ICG-VA and FLOW 800 were used intraoperatively with a specific target in the venous angiographic phase or for the management of venous sacrifice, and whose surgical videos and FLOW 800 analysis were available. RESULTS A total of 296 ICG-VA and FLOW 800 studies were performed intraoperatively. In all cases, the venous structures were clearly identifiable and were described according to the flow direction and speed. The authors therefore defined different patterns of presentation: arterialized veins, thrombosed veins, fast-draining veins with anterograde flow, slow-draining veins with anterograde flow, and slow-draining veins with retrograde flow. In 16 cases we also performed a temporary clipping test to predict the effect of the venous sacrifice by the identification of potential collateral circulation. CONCLUSIONS ICG-VA and FLOW 800 analysis can provide complete and real-time intraoperative information regarding patient-specific venous drainage pattern and can guide the decision-making process regarding venous sacrifice, with a possible impact on reduction of surgical complications.

The role of indocyanine green videoangiography with FLOW 800 analysis for the surgical management of central nervous system tumors: an update.

OBJECTIVE Indocyanine green videoangiography (ICG-VA) is an intraoperative technique used to highlight vessels in neurovascular surgery. Its application in the study of the vascular pathophysiology in CNS tumors and its role in their surgical management are still rather limited. A recent innovation of ICG-VA (i.e., the FLOW 800 algorithm integrated in the surgical microscope) allows a semiquantitative evaluation of cerebral blood flow. The aim of this study was to evaluate for the first time the systematic application of ICG-VA and FLOW 800 analysis during surgical removal of CNS tumors. METHODS Between May 2011 and December 2017, all cases in which ICG-VA and FLOW 800 analysis were used at least one time before, during, or after the tumor resection, and in which surgical videos were available, were retrospectively reviewed. Results of the histological analysis were analyzed together with the intraoperative ICG-VA with FLOW 800 in order to investigate the tumor-related videoangiographic features. RESULTS Seventy-one patients who underwent surgery for cerebral and spinal tumors were intraoperatively analyzed using ICG-VA with FLOW 800, either before or after tumor resection, for a total of 93 videoangiographic studies. The histological diagnosis was meningioma in 25 cases, glioma in 14, metastasis in 7, pineal region tumor in 5, hemangioblastoma in 4, chordoma in 3, and other histological types in 13 cases. The authors identified 4 possible applications of ICG-VA and FLOW 800 in CNS tumor surgery: extradural surveys allowed exploration of sinus patency and the course of veins before dural opening; preresection surveys helped in identifying pathological vascularization (arteriovenous fistulas and neo-angiogenesis) and regional venous outflow, and in performing temporary venous clipping tests, when necessary; postresection surveys were conducted to evaluate arterial and venous patency and parenchymal perfusion after tumor removal; and a premyelotomy survey was conducted in intramedullary tumors to highlight the posterior median sulcus. CONCLUSIONS The authors found ICG-VA with FLOW 800 to be a useful method to monitor blood flow in the exposed vessels and parenchyma during microsurgical removal of CNS tumors in selected cases. In particular, a preresection survey provides useful information about pathophysiological changes of brain vasculature related to the tumor and aids in the individuation of helpful landmarks for the surgical approach, and the postresection survey helps to prevent potential complications associated with the resection (such as local hypoperfusion or venous infarction).

Use of Neuronavigation System for Superficial Vein Identification: Safe and Quick Method to Avoid Intraoperative Bleeding and Vein Closure: Technical Note.

BACKGROUND: Contributions on using navigation in neurosurgery have been shared widely. However, few authors have reported their experience identifying superficial vessels before dural opening using indocyanine green-video angiography. Furthermore, this technique has shown some limitations. METHODS: For many years, each time we planned a needle biopsy for brain tumors, we set the entry point and trajectory on the navigator before surgery. Regarding the target, we systematically chose both a trajectory, which should avoid any crossing with vessels, and an entry far from veins or granulations. Gadolinium-enhanced magnetic resonance imaging T1-weighted sequences have been demonstrated to be adequate for this purpose. Note that we used the Medtronic StealthStation S8 (Minneapolis, Minnesota, USA) and gadolinium-enhanced magnetic resonance imaging T1-weighted sequences to plan 4 different surgical procedures (needle biopsy, parasagittal meningioma, double metastases, and high-grade glioma). Intraoperatively, after craniotomy and dural exposure, a Passive Planar Blunt Probe and dermographic pen were used to mark superficial vessels on the basis of navigational images. The dura was opened far from any marked line, vessels were dissected, and the dura was opened by a Penfield dissector and Metzenbaum scissors. RESULTS: The mean planning time length was 7 minutes, and the marking procedure time length was 3 minutes. Dural marks perfectly corresponded to the underlying vessels. The correspondence rate of marks to underlying vessels was 100%. No one vessel unmarked was noticed. No superficial vessel injuries were reported. CONCLUSIONS: This technique provides a safe and fast method to avoid vessel injuries during dural opening. Furthermore, it could be useful as an educational tool.

Microsurgical Clipping of Intracranial Aneurysms Assisted by Neurophysiological Monitoring, Microvascular Flow Probe, and ICG-VA: Outcomes and Intraoperative Data on a Multimodal Strategy.

OBJECTIVE: The aim of this study is to report data on a multimodal monitoring strategy based on the intraoperative use of neurophysiological monitoring, flowmetry by microflow probe, and intraoperative indocyanine green video angiography (ICG-VA) during microsurgical clipping of intracranial aneurysms. METHODS: This retrospective analysis was performed on 85 consecutive patients undergoing clipping of 96 intracranial aneurysms with the present monitoring strategy. Patient outcomes were evaluated by assessing rate of aneurysm exclusion and postoperative occurrence of ischemic injury. Intraoperative data for the strategy in addition to changes in each monitoring technique depending on aneurysm features were reported. RESULTS: Complete aneurysm exclusion was achieved in 98.9% of cases. Postoperative symptomatic ischemic injury was recorded in 2.08% aneurysms. Clip repositioning occurred in 40.6% of cases: because of motor evoked potential (MEP) decrease in 9.3%, flowmetry in 22.91%, and ICG-VA in 8.3% of treated aneurysms (1.05% after ICG injection, 7.4% after the squeezing maneuver). The role of each technique differed according to aneurysm features; flowmetry alterations occurred more frequently in distal than in proximal aneurysms (P = 0.0001) and in atherosclerotic aneurysms (P = 0.0001). MEP impairment occurred more often in proximal aneurysms (P < 0.05). ICG-VA disclosed remnant aneurysms mainly in atherosclerotic aneurysms (P < 0.05); only one false negative remnant neck was recorded with a negative predictive value of 98.8%. CONCLUSIONS: Microsurgical clipping assisted by a multimodal monitoring strategy achieved a high rate of aneurysm exclusion with low morbidity in our series. Our data show that the 3 techniques used in our strategy were complementary and that a monitoring strategy can be tailored to aneurysm features.

Correlation between reduction in microvascular transit time after superficial temporal artery-middle cerebral artery bypass surgery for moyamoya disease and the development of postoperative hyperperfusion syndrome.

OBJECTIVE Hyperperfusion syndrome (HPS) is a notable complication that causes various neurological symptoms after superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery for moyamoya disease (MMD). The authors used intraoperative indocyanine green (ICG) videoangiography to measure the change in microvascular transit time (MVTT) after bypass surgery. An analysis was then conducted to identify the correlation between change in MVTT and presence of postoperative HPS. METHODS This study included 105 hemispheres of 81 patients with MMD who underwent STA-MCA single bypass surgery between January 2010 and January 2015. Intraoperative ICG videoangiography was performed before and after bypass surgery. The MVTT was calculated from the ICG time intensity curve recorded in the pial arterioles and venules. Multivariate logistic regression analysis was conducted to test the effect of multiple variables, including the change in MVTT after bypass surgery, on postoperative HPS. RESULTS Postoperative HPS developed in 28 (26.7%) of the 105 hemispheres operated on. MVTT was reduced significantly after bypass surgery (prebypass 5.34 ± 2.00 sec vs postbypass 4.12 ± 1.60 sec; p < 0.001). The difference between prebypass and postbypass MVTT values, defined as ΔMVTT, was significantly greater in the HPS group than in the non-HPS group (2.55 ± 2.66 sec vs 0.75 ± 1.78 sec; p < 0.001). Receiver operating characteristic curve analysis revealed that the optimal cutoff point of ΔMVTT was 2.6 seconds (sensitivity 46.4% and specificity 85.7% as a predictor of postoperative HPS). A ΔMVTT > 2.6 seconds was an independent predictor of HPS in multivariate analysis (hazard ratio 4.88, 95% CI 1.76-13.57; p = 0.002). CONCLUSIONS MVTT in patients with MMD was reduced significantly after bypass surgery. Patients with a ΔMVTT > 2.6 seconds tended to develop postoperative HPS. Because ΔMVTT can be easily measured during surgery, it is a useful diagnostic tool for identifying patients at high risk for HPS after STA-MCA bypass surgery for MMD.

Utility of indocyanine green videoangiography in subcortical arteriovenous malformation resection.

Subcortical arteriovenous malformations (AVMs) are surgically challenging. Localization is crucial for eloquent areas, and complete resection evaluation is uncertain. Indocyanine green videoangiography (ICG-VA) can assist this surgery. An illustrative video of a subcortical frontoparietal bleeding AVM resection assisted by ICG-VA is presented. A bleeding arterial feeder aneurysm was embolized in the acute phase to protect against rebleeding. ICG-VA helped to detect the AVM's superficial arterialized draining vein, distinguishing it from normal cortical veins. This enabled a customized sulcus approach. ICG-VA showed normalized flow through the previously arterialized vein, confirming the AVM's complete resection. This applies when there is a single drainage remaining. The video can be found here: https://youtu.be/L7yJEE66kV0 .

The "ICG Entrapment Sign" in Cerebral Aneurysm Surgery Assisted by Indocyanine Green Videoangiography.

BACKGROUND: Indocyanine green videoangiography (ICG-VA) after clipping can be misleading in evaluating aneurysm exclusion when the dye is injected before clipping. This is due to indocyanine green (ICG) entrapment by the clip blades in the aneurysm dome. METHODS: We examined the intraoperative findings of 7 patients presenting ICG entrapment. In all cases, the clipped aneurysms were opened intraoperatively at the end of the procedure to confirm aneurysm exclusion. RESULTS: In 4 cases ICG entrapment was caused by dye injection before clipping for the surgical strategy and in 3 cases because the clip was repositioned based on ICG-VA findings. In all cases, the final sac opening confirmed that the dye entrapment indicated complete aneurysm exclusion. In our experience ICG entrapment avoided a second ICG injection in 2 cases and yielded a better understanding of the videoangiographic findings in 5 patients. CONCLUSIONS: The "ICG entrapment sign" can be used intraoperatively as an indirect sign of excluded aneurysm and can be helpful in the decision-making process for aneurysm treatment when ICG-VA is performed before clipping.

Multimodal Flow-Assisted Resection of Brain AVMs.

OBJECT: The authors report their personal experience with brain arterio-venous malformations (bAVMs) surgery with a multimodal flow-assisted approach. METHODS: Data from patients who consecutively underwent bAVM resection with the assistance of indocyanine green video-angiography (ICG-VA), micro-flow probe flowmetry, and temporary arterial clipping test under intra-operative monitoring, were retrospectively analyzed. RESULTS: Twenty seven patients were enrolled in the study. Re-operation for residual nidus was needed in one case (3 %). Average mRS change 1 month after surgery was +0.02. In our experience, the multimodal flow-assisted approach enabled surgeons to shift from one technique to another, according to the stage of resection, AVM location, or specific issues to be addressed. Before resection, the value of ICG-VA and flowmetry in showing AVM angio-architecture and guiding surgical strategy was related to AVM features. The temporary arterial clipping-test presented a 100 % sensitivity to differentiate between an AVM feeder and a transit artery to the sensi-motor area. At the final stage of resection, flowmetry was more effective than ICG-VA in detecting residual nidus missed at dissection. CONCLUSIONS: Multimodal flow-assisted approach in AVM surgery proved a feasible, safe, and reliable methodology to achieve AVM resection with high radicality and low morbidity rate.

Indocyanine Green Videoangiography Transoptic Visualization and Clipping Confirmation of an Optic Splitting Ophthalmic Artery Aneurysm.

OBJECTIVE: Ophthalmic artery aneurysms with medial and superior projection in exceptionally rare cases can split the optic nerve. Treatment of these aneurysms is challenging, because the aneurysm dome is hidden from the optic nerve, rendering its visualization and clipping confirmation difficult. In addition, optic nerve function should be preserved during surgical maneuvers. Preoperative detection of this growing feature is usually missing. CASE DESCRIPTION: We illustrate the first case of indocyanine green videoangiography (ICG-VA) application in an optic penetrating ophthalmic artery aneurysm treatment. A 57-year-old woman presented with temporal hemianopsia, slight right visual acuity deficit, and new onset of headache. The cerebral angiography detected a right ophthalmic artery aneurysm medially and superiorly projecting. The A1 tract of the ipsilateral anterior cerebral artery was elevated and curved, being suspicious for an under optic aneurysm growth. Surgery was performed. Initially the aneurysm was not visible. ICG-VA permitted the transoptic aneurysm visualization. After optic canal opening, the aneurysm was clipped and transoptic ICG-VA confirmed the aneurysm occlusion. ICG-VA showed also the slight improvement of the optic nerve pial vascularization. Postoperatively, the visual acuity was 10/10 and the hemianopsia did not worsen. CONCLUSIONS: The elevation and curve of the A1 tract in medially and superiorly projecting ophthalmic aneurysms may be an indirect sign of under optic growth, or optic splitting aneurysms. ICG-VA transoptic aneurysm detection and occlusion confirmation reduces the surgical maneuvers on the optic nerve, contributing to function preservation.

Indocyanine green videoangiography for the identification of superficial temporal artery branches in EC-IC bypass surgery.

BACKGROUND: Superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass remains an essential tool for managing complex cerebrovascular conditions. A crucial surgical step is the identification and safe dissection of the bypass donor artery. If the frontal branch of the STA is used, a curvilinear fronto-temporal scalp flap generally allows for a clean dissection from the underside of the scalp flap. This dissection is sometimes tedious, since the frontal branch is not always easily visible and due to variability of its anatomy. With this article, we report on the feasibility and effectiveness of a simple indocyanine green videoangiography (ICG-VA)-assisted technique for the identification of the STA branches from the underside of a fronto-temporal scalp flap in bypass surgery. METHODS: The technique is based on the analysis of the difference in timing of filling of scalp vessels illuminated via ICG-VA from the underside of a scalp flap. Three illustrative cases are reported. RESULTS: ICG-VA permitted the correct identification and safe dissection of the donor vessels (STA branches) in all three patients. There were no complications due to the ICG-VA. CONCLUSIONS: This technique allows reliable visualization of the STA and its branches at once before microsurgical dissection. The information provided by ICG-VA enables precise mapping and preparation of the STA. The simplicity and safety of this technique make it an effective tool for intraoperative identification of the STA and its branches.

ICG-VA application in subtemporal transtentorial treatment of a Cognard V dural arteriovenous fistula.

Intracranial dural arteriovenous fistulas (dAVF) with cervical perimedullary drainage, Cognard V, are a surgically challenging rare entity. In this video we show the disconnection of a right tentorial Cognard V dAVF, done through a subtemporal transtentorial approach with the application of indocyanine green video angiography. A 47-year-old man presented with severe tetraparesis. Only partial embolization was possible. An osteoplastic frontotemporal craniotomy was performed to obtain a wide view along with CSF release to safely mobilize the temporal lobe. Neuronavigation was used to detect the fistula and indocyanine to detect the tentorial afferent arteries and to confirm final disconnection. The video can be found here: https://youtu.be/Yr8tAiiHNXU .

Indocyanine green video-angiography in neurosurgery: a glance beyond vascular applications.

OBJECTIVE: Indocyanine green video angiography (ICG-VA) is a non invasive, easy to use and a very useful tool for various neurosurgical procedures. Initially introduced in vascular neurosurgery since 2003, it's applications have broadened over time, both in vascular applications and in other neurosurgical fields. The objective of our study is to review all published literature about ICG-VA, cataloguing its different applications. METHODS: A systematic review of all pertinent literature articles published from January 2003 to May 2014 using Pubmed access was performed using pertinent keywords; cross check of references of selected articles was performed in order to complete bibliographical research. Results of research were grouped by pathology. RESULTS AND CONCLUSIONS: The paper systematically analyses ICG-VA different applications in neurosurgery, from vascular neurosurgery to tumor resection and endoscopic applications, focusing on reported advantages and disadvantages, and discussing future perspectives.