ICG Videoangiography Research Articles

Comparison of intraoperative sodium fluorescein and indocyanine green videoangiography during intracranial aneurysm and arteriovenous malformation surgery

ObjectiveIndocyanine green (ICG) and sodium fluorescein (Na-Fl) are two fluorophores, which are used for videoangiography purposes. This prospective study reports our experience by using surgical microscopes equipped with two special filters. We compared the imaging efficacy of Na-FL and ICG videoangiography techniques during aneurysm and arteriovenous malformations (AVM) surgeries.Patient and methods:Fourtynine consecutive patients were operated between September 2015 and December 2022. Patients with ruptured/unruptured aneurysms or with AVMs presented with/without hemorrhage were included to the current study. ResultsThere were a total of 48 aneurysms and 11 AVMs in 49 patients in the current study. Na-Fl enables the surgeon to manipulate vessels and aneurysms real-time. ICG provides the ability to watch the videoangiography repeatedly and understand the angioarchitecture. The use of FLOW-800 module allows the surgeon to make concrete judgements about the flow dynamics of AVMs and therefore ICG videoangiography found useful in AVM surgery. Na-Fl has been found more useful for the evalution of the low caliber perforating arteries and anatomical features of the aneursym dome in aneurysm surgery. ConclusionThe results of our series demonstrated the safety and efficacy of Na-Fl use in the surgery of aneurysms and AVMs. Both the ICG and Na-Fl videoangiographies are easy to perform and complimentary to each other. Combined use of these two mediums may provide better surgical results, considering the separate advantages and disadvantages of these both techniques.

Improved rates of postoperative ischemia, completeness of aneurysm occlusion and neurological deficits in elective clipping of anterior circulation aneurysms over the past 20 years – association with technical improvements

Background/PurposeSeveral periprocedural adjuncts for elective surgical aneurysm treatment have been introduced over the last 20 years to increase safety and efficacy. Besides the introduction of IONM in the late-1990s, ICG-videoangiography (ICG-VAG) since the mid-2000s and intraoperative CT-angiography/-perfusion (iCT-A/-P) since the mid-2010s are available. We aimed to clarify whether the introduction of ICG-VAG and iCT-A/-P resulted in our department in a stepwise improvement in the rate of radiologically detected postoperative ischemia, complete aneurysm occlusion and postoperative new deficits.MethodsPatients undergoing microsurgical clip occlusion for unruptured anterior circulation aneurysms between 2000 and 2019 were included, with ICG-VAG since 2009 and iCT-A/-P (for selected cases) since 2016. Baseline characteristics and treatment-related morbidity/outcome focusing on differences between the three distinct cohorts (cohort-I: pre-ICG-VAG-era, cohort-II: ICG-VAG-era, cohort-III: ICG-VAG&iCT-A/-P-era) were analyzed.Results1391 patients were enrolled (n = 74 were excluded), 779 patients were interventionally treated, 538 patients were surgically clipped by a specialized vascular team (cohort-I n = 167, cohort-II n = 284, cohort-III n = 87). Aneurysm size was larger in cohort-I (8.9 vs. 7.5/6.8 mm; p < 0.01) without differences concerning age (mean:55years), gender distribution (m: f = 1:2.6) and aneurysm location (MCA:61%, ICA:18%, ACA/AcomA:21%). There was a stepwise improvement in the rate of radiologically detected postoperative ischemia (16.2vs.12.0vs.8.0%; p = 0.161), complete aneurysm occlusion (68.3vs.83.6vs.91.0%; p < 0.01) and postoperative new deficits (10.8vs.7.7vs.5.7%; p = 0.335) from cohort-I to -III. After a mean follow-up of 12months, a median modified Rankin scale of 0 was achieved in all cohorts.DiscussionAssociated with periprocedural technical achievements, surgical outcome in elective anterior circulation aneurysm surgery has improved in our service during the past 20 years.

Comparative Study of Intraoperative Fluorescein and Indocyanine Green Videoangiography for Ruptured Cerebral Aneurysms Clipping: A Single Centre Study of 30 Cases.

Aim This study assesses the application of microscope integrated videoangiography techniques in aneurysm clipping surgery using Indocyanine Green and Fluorescein fluorophores and evaluates merits and demerits of each technique. Materials and Methods Total 30 patients of cerebral aneurysmal clipping were included. Standard microsurgical procedures were done. After clipping, we administered a 25 mg bolus intravenous dose of indocyanine green with microscope focused through the INFRARED 800 camera module, followed by administration of 60 mg bolus intravenous dose of fluorescein with microscope focused through the yellow 560 module and images were assessed. Results The average aneurysm size was 17 mm. In 12 patients (40%), FL-VA allowed better assessment of perforating arteries (seven cases) or distal branches (three cases) or both (two cases), when compared with ICG-VA. In one case of MCA (M1) aneurysm, ICG-VA showed no fluorescent signal in one of the distal trunks whereas FL-VA showed normal signal. In one case of ACOM aneurysm, perforators were missed on ICG-VA but were seen on FL-VA. FL-VA was able to identify inadequate aneurysm clipping in one case. In two patients, FL-VA provided the advantage of real-time manipulation of the vessels to expose the vessels and aneurysms of interest. Fluorescein detected all the perforators that were visible under white light (68/68) whereas ICG was able to detect 56 (82.35%) perforators ( p -value< 0.05). Conclusion Intraoperative ICG and Fluorescein videoangiography recognize inadequate occlusion of aneurysm, decreased flow in branches or perforators. When various study parameters were considered such as ability to assess small size perforators, branching vessels, adequacy of aneurysmal clipping, and useful information on repeat imaging, FL-VA was found superior to ICG-VA.

Tailored Skull Base Approach to Management of Intracranial Aneurysms.

Surgical management of intracranial aneurysms (IAs) remains one of the most challenging and dynamic tasks for neurosurgeons. The rivalry between modern time microsurgery and progress in endovascular intervention has provided a great arena for advancement and lead to redefine training concept and referral pattern. Both approaches has its own merits, risks and complications and the best outcome is achieved by case individualization and complimentary multidisciplinary approach.The recent innovation in microscopic and endoscopic tailored skull base approaches, intraoperative 3D and ICG video-angiography, design of high quality aneurysm clips, and refinement of cerebral bypass techniques enhance IAs neurosurgical management and their clinical outcome. The command of tailored skull base approaches should be part of the training curriculum of young generation of neurosurgeons to compliment the emerging treatment options of endovascular intervention.

Multimodality Management in bAVM Surgery - Recent Experience from International Cerebrovascular Fellowship.

Background:Arteriovenous malformation (bAVM) presents maldevelopment of the brain’s vessels with a direct connection between cerebral arteries and veins. By current data, patients from Spetzler Ponce A (SP) are found to benefit from the treatment. Considering the outcome, most of SP C and some of the SP B are the most debatable.Objective:Arteriovenous malformation presents maldevelopment of the brain’s vessels with a consequent direct connection between cerebral arteries and veins. The annual risk of hemorrhage in adults is reported for 2-3 %. They usually present with unilateral headaches seizures and intracranial hemorrhage. By current data, patients from Spetzler Ponce A (SP) are found to benefit from the treatment. Considering the outcome, most of SP C and some of the SP B are the most debatable.Methods:The study included a cohort of bAVM patients referred to Fujita Health University Bantane Hotokukai Hospital, Nagoya, Aichi, Japan where the main author (AA) has completed an international cerebrovascular fellowship under the mentorship of Professor Yoko Kato. Japanese Stroke Guidelines (JSG) were used for the treatment decision. Patients were graded according to the Spetzler Ponce (SP) system. Considering American Heart Association criteria (AHA), embolization was used as a part of multimodal treatment. Intraoperative microscopic video tools included Indocyanine green ICG, FLOW 800 and dual image video angiography DIVA. Clinical outcomes were measured using Modified Ranking Score (mRs).Results:A total of eleven patients with brain bAVM were studied with a median age of 32 years [IQR = 22-52]. There were ten patients presented with supratentorial and a single patient with infratentorial AVM. Patients were graded according to the Spetzler Ponce (SP) system. There were eight patients in SP A (72,7%), one in group B (9 %) while the rest of them were in C (18 %). Two patients had associated aneurysms that required treatment. The median size of the AVM nidus was 3,50 cm [IQR= 2-5]. Deep venous drainage was found in six patients while three were located in eloquent zones. Clinical outcomes were considered good by mRs <2 in eight patients, seven from the surgically treated group (72,7 % respectively). Surgery median length time was 427, 5 minutes; [IQR =320 - 463] with complete AVM resection in all patients and no mortality recorded in this cohort with the median follow up of 39,5 months [IQR = 19-59].Conclusion:Ideal management of bAVM is still controversial. Those complex vascular lesions require multimodal treatment in a majority of cases in highly specialized centers. In SP A patients, surgery provides the best results with a positive outcome and a small number of complications. With the improvement of endovascular feeder occlusion SP B patients become prone to a more positive outcome. Nowadays, intraoperative microscopic tools such as FLOW 800, ICG and DIVA are irreplaceable while improving safety to deal with bAVM. For SP C patients, a combination of endovascular and stereotactic radiosurgery was found to be a good option in the present time.

Application of Indocyanine Green Videoangiography in Aneurysm Surgery: Evidence, Techniques, Practical Tips.

Establishing blood vessel patency in neurovascular surgery is an essential component in treating cerebrovascular disorders. Given the difficulty in confirming complete obliteration of the aneurysm sac, ICG videoangiography has emerged as an intraoperative tool that provides neurosurgeons immediate feedback on the status of vessel flow, allowing for surgical modifications to be made without delay. ICG initially emerged as a tool for assessing hepatic, cardiac, and retinovascular function. It is an inert compound with a high affinity for plasma proteins and fluorescence properties making it the ideal candidate for assessment of vessel patency in neurovascular procedures. Requiring only a bolus peripheral vein injection and integration of a near-infrared imaging device into the surgical microscope, ICG can be visualized without disrupting operating room workflow or the surgical field. Quick response time, high-spatial resolution, and low complication rates are features of ICG videoangiography that prove advantageous when compared to the gold standard intra- and postoperative digital subtraction angiography (DSA). Despite this, ICG is not without limitations, specifically in the setting of atherosclerotic vessels, giant, and complex aneurysms. Additionally, there are instances where DSA may prove superior in detecting vessel stenosis and outflow obstruction, prompting the recommendation of ICG as an adjunct to, rather than complete replacement of DSA. In this article, the authors provide a brief overview of the biochemical properties and historical origins of ICG viedoangiography in addition to discussing its current application in aneurysm surgery.

Abstract TP583: Consideration on Surgical Treatment of Arteriovenous Fistula at the Craniocervical Junction

Objective: Management of arteriovenous fistula at the craniocervical junction (CCJ-AVF) is challenging, because CCJ-AVF is quite rare, most cases are difficult to treat by the endovascular treatment only, and difficult to understand its complicated anatomy preoperatively. The aim of this presentation is to propose several tips and pitfalls regarding the surgical strategy for CCJ-AVF, particularly focused on anatomical relationships with shunting point and key structures. Methods: We experienced 9 cases of CCJ-AVF during about 4 years since April 2015. These patients presented by as follows, 3 subarachnoid hemorrhage, 2 hematomyelia, 1 cerebellar hemorrhage, and 3 incindentally. We performed surgical ligation for 8 cases and endovascular treatment for 2 cases, including combined therapy for one case in each. Direct surgery was usually performed as follows: general anesthesia, park-bench position, transcondylar fossa approach and C1 laminectomy, cut the dentate ligament with MEP/SEP and NIM monitoring and ICG video angiography repeatedly. Results: Postoperative DSA showed a complete cure in every case. One case treated by surgical ligation had a transient neurological deficit, while another case treated by endovascular treatment showed deterioration of preoperative motor dysfunction. Conclusions: For CCJ-AVFs, we prefer direct surgical ligation, because this lesion has a dangerous anastomoses between radiculo-meningeal and pial supply which cannot be detect preoperatively. Our approach can provide a suitable operative field to ensure understanding of its complicated structure. In our series, the patients who underwent surgical ligation had a good result except one patient with transient neurological deficit caused by postoperative excessive venous thrombosis of the drainer which required temporary anticoagulation.

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.

Editorial. The use of ICG videoangiography and FLOW 800 analysis.

Editorial. The use of ICG videoangiography and FLOW 800 analysis.

Endo ICG videoangiography: localizing the carotid artery in skull-base endonasal approaches.

In this work, the applicability of ICG-VA to skull base endoscopic surgery and its capacity to locate the internal carotid artery are shown. An adapted optical module to perform ICG-VA was used to perform endoscopic procedures. There were two intraoperative phases of interest that were used to evaluate the ICA: upon exposure of the skull base and during the intradural exploration. This new tool for obtaining ICA images in real time (as opposed to with navigation), and it is demonstrated that this tool provides a superior ability to detect the margins of the ICA compared with the Doppler technique. On the other hand, the present technique also provides enhancement of the artery through the bone of the skull base without the need for drilling. ICG-VA is a safe and effective technique for locating the ICA in skull-base expanded endonasal surgery. Furthermore, this technique can provide real-time guidance for the surgeon and increase safety for the patient.

Clipping Surgery for Unruptured Middle Cerebral Artery Aneurysms.

Clipping surgeries for 139 consecutive unruptured middle cerebral aneurysms were performed between April 1991 and March 2014. Left hemiparesis occurred in one case (0.7 %). Transient symptoms arose in six patients due to perforator injury, arterial branch occlusion, damage to the venous system, or chronic subdural hematoma. Neither mortality nor decline in cognitive function was noted in this study. Clipping surgery for unruptured middle cerebral artery aneurysms can be done with minimal morbidity. However, meticulous management during the perioperative period as well as the use of modern technologies during the surgery, such as MEP monitoring and ICG videoangiography, are needed for safe and secure clipping surgery.

Use of ICG Videoangiography in Surgical Treatment of Spinal Dural Arterovenous Fistulas sdavf

Introduction: It is recognized that a timely diagnosis, followed by the occlusion of the shunting zone during surgical treatment, are essential in the spinal dural arterio-venous fistulas treatment. Our purpose is to show that better results can be obtained using intraoperative Indocianine green colour video angiography pre and post clipping during the surgical procedures. Methods: interruption of abnormal arterovenous connection is the aim of the treatment of spinal dural artero-venous fistulas. In order to focus, exactly, point of fistula, we used Indocianine green video angiography intra operative during 18 surgical procedures before positioning the clip, and after that, to control the correct vascular reset. A 48 hours post operative control angiography has been performed in all patients. Clinical follow up lasted approximately 7 months. Results: Intraoperative Indocianine video angiography was used in all 18 cases and the occlusion of the DAVF at post-operative angiography was confirmed in 17 cases. One patient has been retreated because of a minimal residual fistula. No side effects due to the indocianine videoangiography have been reported. Conclusions: Use of intraoperative indocianine videoangiography represent a safe method to investigate the malformation during surgery and allow to obtain excellent results in the treatment of sDAVF.

術前3Dシミュレーションと術中血流評価により安全に摘出できたeloquent area近傍に存在する非表在性脳動静脈奇形の1例

術前3Dシミュレーションと術中血流評価により安全に摘出できたeloquent area近傍に存在する非表在性脳動静脈奇形の1例

Visualization of declamping procedure during carotid endarterectomy by ICG videoangiography

Background. ICG videoangiography (ICG-VAG) is widely used in neurovascular surgery. In carotid artery disease, it has been used to assess the extent of the plaque and to confirm the removal of the plaque and patency of the artery. We introduce a novel usage of the ICG-VAG to confirm the patency of the external carotid artery (ECA) and superior thyroid artery (STA), which should work as a drainage system of possible debris in the lumen. Method. Consecutive 27 patients with severe internal carotid artery stenosis were employed. Carotid endarterectomy (CEA) was done in the usual fashion. After suturing the arteriotomy, ICG was injected intravenously before reperfusion. Before declamping procedure, ICG-VAG mode was started. As the declamping procedure went on, the assistant judged whether the STA and the ECA were patent by watching the ICG flow on the monitor. After confirming the patency of the ECA–CCA system, the ICA was reperfused. Result. The back flow from the STA was not confirmed in two cases. The back flow from the ECA was confirmed in all 27 cases. In four cases, the ICG-VAG showed air bubbles in the lumen; these bubbles were washed away to the ECA or STA. Conclusion. Using ICG-VAG during the reperfusion procedure of CEA, the patency of the ECA and the STA can be confirmed. It may contribute to reduce embolic complication during reperfusion procedure.

穿通枝の外科解剖^|^mdash;ICG videoangiographyと神経内視鏡の有用性^|^mdash;

穿通枝障害は重篤な神経症状を生じることが多いため, その外科解剖を理解することは脳神経外科顕微鏡手術においてきわめて重要である. 特に, 脳動脈瘤クリッピング術の際は, 穿通枝の解剖学的バリエーションと脳動脈瘤との関係について理解しておく必要がある. 前脈絡叢動脈は, 動脈瘤のドームから起始することもあり, また2～4本存在することがあるため, そのような場合には注意が必要である. レンズ核線条体動脈は通常中大脳動脈水平部 (M1部) の後壁から分岐するが, 時としてM1-2分岐部やM2から起始する. 視床下部動脈は前交通動脈の後面から起始するため, pterional approachでは確認することが困難である. 穿通枝の温存のためには, 動脈瘤周囲の穿通枝をすべて確認することが必要で, 神経内視鏡は顕微鏡の死角となる部分の観察に有用である. 穿通枝の血流を温存するようにクリップをかけ, クリッピング後はドップラー超音波流量計, ICG蛍光血管造影, 運動誘発電位などの神経生理学的モニタリングなどの術中モニタリングで穿通枝の温存を確認する. それぞれのモニタリングには偽陰性が生じ得るため, 複数のモニタリングを組み合わせて使用することが重要である.

Flow-based evaluation of cerebral revascularization using near-infrared indocyanine green videoangiography

Indocyanine green (ICG) videoangiography has been established as a noninvasive technique to gauge the patency of a bypass graft; however, intraoperative graft patency may not always correlate with graft flow. Altered flow through the bypass graft may directly cause delayed graft occlusion. Here, the authors report on 3 types of flow that were observed through cerebral revascularization procedures. Between February 2009 and September 2013, 48 bypass procedures were performed. Excluded from analysis were those cases in which ICG videoangiography was not performed during surgery (whether it was not available or there was a technical issue with the microscope or the quality of ICG angiography) and/or in which angiography or CT angiography was not done within 24-72 hours after surgery. After anastomosis, bypass patency was assessed first using a noninvasive technique and then with ICG videoangiography, and flow through the graft was characterized. Patients who received a vein or radial artery graft were also evaluated with intraoperative angiography. Thirty-three patients eligible for analysis were retrospectively analyzed. The patients had undergone extracranial-intracranial (EC-IC) or IC-IC bypass for ischemic stroke (13 patients), moyamoya disease (10 patients), and complex aneurysms (10 patients; 6 giant or large aneurysms, 2 carotid blister-like aneurysms, and 2 dissecting posterior inferior cerebellar artery [PICA] aneurysms). Thirty-six bypasses were performed including 26 superficial temporal artery (STA)-middle cerebral artery (MCA) bypasses (2 bilateral and 1 double-barrel), 6 EC-IC vein grafts, 1 EC-IC radial artery graft, 1 PICA-PICA bypass, 1 MCA-posterior cerebral artery bypass, and 1 occipital artery-PICA bypass. Robust anterograde flow (Type I) was noted in 31 grafts (86%). Delayed but patent graft enhancement and anterograde flow (Type II) was observed in 4 cases (11%); 1 of these cases with an EC-IC vein graft degraded gradually to very delayed flow with no continuity to the bypass site (Type III). Additionally, 1 STA-MCA bypass graft revealed no convincing flow (Type III). The 5 patients with Type II or III grafts were evaluated with a flow probe and reexploration of the bypass site, and in all cases the reason the graft became occluded was believed to be recipient-vessel competitive flow. In no case was there evidence of stenosis or a technical issue at the site of the anastomosis. Three patients with Type II and the 1 patient with Type III flow (11% of procedures) did not have a patent bypass on postoperative imaging. Indocyanine green videoangiography is reliable for evaluating flow through the EC-IC or IC-IC bypass. The type of flow observed through the graft has a direct relationship with postoperative imaging findings. Despite the possibility of competitive flow, Type III and some Type II flows through the graft indicate the need for graft evaluation and anastomosis exploration.

The usefulness of ICG video angiography in the surgical treatment of superior cluneal nerve entrapment neuropathy

Superior cluneal nerve (SCN) entrapment neuropathy is a known cause of low back pain. Although surgical release at the entrapment point of the osteofibrous orifice is effective, intraoperative identification of the thin SCN in thick fat tissue and confirmation of sufficient decompression are difficult. Intraoperative indocyanine green video angiography (ICG-VA) is simple, clearly demonstrates the vascular flow dynamics, and provides real-time information on vascular patency and flow. The peripheral nerve is supplied from epineurial vessels around the nerve (vasa nervorum), and the authors now present the first ICG-VA documentation of the technique and usefulness of peripheral nerve neurolysis surgery to treat SCN entrapment neuropathy in 16 locally anesthetized patients. Clinical outcomes were assessed with the Roland-Morris Disability Questionnaire before surgery and at the latest follow-up after surgery. Indocyanine green video angiography was useful for identifying the SCN in fat tissue. It showed that the SCN penetrated and was entrapped by the thoracolumbar fascia through the orifice just before crossing over the iliac crest in all patients. The SCN was decompressed by dissection of the fascia from the orifice. Indocyanine green video angiography visualized the SCN and its termination at the entrapment point. After sufficient decompression, the SCN was clearly visualized on ICG-VA images. Low back pain improved significantly, from a preoperative Roland-Morris Questionnaire score of 13.8 to a postoperative score of 1.3 at the last follow-up visit (p < 0.05). The authors suggest that ICG-VA is useful for the inspection of peripheral nerves such as the SCN and helps to identify the SCN and to confirm sufficient decompression at surgery for SCN entrapment.

The role of indocyanine green videoangiography (ICGV) in surgery of parasagittal meningiomas

Dear Editor,We read with great interest the paper entitled “Indocyaninegreenvideoangiography(ICGV)-guidedsurgeryofparasagittalmeningiomas occluding the superior sagittal sinus (SSS) ” byD’Avellaetal.[1].Theauthorsnicelydescribeandfocusontheopportunities that intraoperative ICG videoangiography offersduring surgery of parasagittal meningiomas. We completelyagree with them on the role of extradural examination, whichhas been recently illustrated by Nurshaum et al. [ 5]. We alsoagree on the key role of bridging veins that drain normalparenchyma, and the delicate balance between the need formaximizing resection and preserving neurological function.The authors rightly say: “This technique adds useful informa-tion to the surgeon’s effort to preserve normal venous vascula-ture.” However, their ICG-guided decision making processwith respect to venous sacrifice is not described in detail. Dotheythinkthatbridgingveinswithflowinversioncanbesafelysacrificed? In our experience, this was not found to be true,since we observed that a relief of mass effect after tumordebulking can re-establish flow in an anterograde directionand possibly contribute to reducing peritumoral edema due tovenous congestion [2]. Thus, the direction of venous flowbefore the removal of the meningioma cannot be consideredthe key point. In addition, the problem of venous sacrificeduring surgical approaches for parasagittal meningiomas isnot exhaustively addressed. We recently contributed in thisfield with two papers that describe the use of ICGvideoangiography to evaluate the presence of a collateral ve-nous drainage through an ad hoc designed temporary clippingtest [3, 4]. This technique was widely discussed in many localand international meetings focused on the issue of parasagittalmeningiomas. The authors should be complimented for theircontribution in this field, but indeed their paper does not seemto address the real and critical issue of when during a neuro-surgical procedure a vein can be sacrificed without clinicalconsequences.

Indocyanine green videoangiography (ICGV)-guided surgery of parasagittal meningiomas occluding the superior sagittal sinus (SSS)

Maximal safe resection is the goal of correct surgical treatment of parasagittal meningiomas, and it is intimately related to the venous anatomy both near and directly involved by the tumor. Indocyanine green videoangiography (ICGV) has already been advocated as an intra-operative resourceful technique in brain tumor surgery for the identification of vessels. The aim of this study was to investigate the role of ICGV in surgery of parasagittal meningiomas occluding the superior sagittal sinus (SSS). In this study, we prospectively analyzed clinical, radiological and intra-operative findings of patients affected by parasagittal meningioma occluding the SSS, who underwent ICGV assisted-surgery. Radiological diagnosis of complete SSS occlusion was pre-operatively established in all cases. ICGV was performed before dural opening, before and during tumor resection, at the end of the procedure. Five patients were included in our study. In all cases, ICGV guided dural opening, tumor resection, and venous management. The venous collateral pathway was easily identified and preserved in all cases. Radical resection was achieved in four cases. Surgery was uneventful in all cases. Despite the small number of patients, our study shows that ICG videoangiography could play a crucial role in guiding surgery of parasagittal meningioma occluding the SSS. Further studies are needed to define the role of this technique on functional and oncological outcome of these patients.

Retinal Angiomatous Proliferations: When Should We Suspect Them and How Should We Detect Them?

The aim of this study was to identify the clinical and angiographic features of retinal angiomatous proliferations (RAPs) in patients with age-related macular degeneration. 26 eyes of 24 patients with RAPs were retrospectively reviewed. All patients had colour and red-free photographs, and fluorescein (FA) and indocyanine-green angiography (ICGA). The biomicroscopic and angiographic characteristics were evaluated and video-angiograms were analysed for staging the RAPs. The total number of RAPs was 29. Stage 1 was present in 3/29, stage 2 in 3/29 and stage 3 in 23/29 with a chorio-retinal anastomosis identified in 21 of these 23 eyes. The total number of retinal vessels involved were 83, 35 were arteries and 48 were veins. RAPs were seen in ICGA as hot spots in all but one case where it appeared as a plaque. A retinal pigment epithelial detachment (PED) was observed in 22/26 eyes. Cystoid macular oedema was observed in 13/26 eyes in FA and intraretinal ICG leakage in 6/26 eyes. Hard exudates were present in 21/26 eyes. Retinal haemorrhages were present in 23/26 eyes; all but one were intraretinal and had a size of less than half of the optic disc diameter. The RAP was bilateral in 2/24 patients. Clinicians should suspect the diagnosis of RAP when hard exudates, small intraretinal haemorrhages, PED or a hot spot in ICGA are present. Both fluorescein and ICG video-angiography provide adequate temporal resolution and vascular flow examination leading to easier RAP staging and identification of the anastomosis.