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OBJECTIVEThe 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.METHODSBetween 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.RESULTSA 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.CONCLUSIONSICG-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.

OBJECTIVEIndocyanine 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.METHODSBetween 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.RESULTSSeventy-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.CONCLUSIONSThe 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).

Hemangioblastomas are benign, highly vascularized intramedullary lesions that may also extend into the intradural space. Surgery represents the standard therapy, with the goal of obtaining complete resection even at the risk of neurological morbidity. MRI is the gold standard for diagnosis and assessment of intramedullary tumors. Nevertheless, sometimes MRI may not accurately differentiate between different types of intramedullary tumors, in particular if they are associated with syringes or intra- and peritumoral cysts. This could subsequently affect surgical strategies. Intraoperative ultrasound (ioUS) has become in the last few years a very useful tool for use during neurosurgical procedures. Various ioUS modalities such as B-mode and Doppler have been applied during neurosurgical procedures. On the other hand, the use of contrast-enhanced ultrasound (CEUS) is not yet well defined and standardized in this field. We report a case of a young patient harboring a cervicothoracic intramedullary tumor, for which the preoperative neuroradiologi-cal diagnosis was in favor of a diffuse astrocytoma with nodular components whereas ioUS demonstrated 3 distinct intramedullary nodules. CEUS showed highly vascularized lesions, compatible with hemangioblastomas. These findings, particularly those obtained with CEUS, allowed better definition of the lesions for diagnosis, enhanced understanding of the physiopathological aspects, and permitted the localization of all 3 nodules, thus limiting spinal cord manipulation and allowing complete resection of the lesions, with an uneventful postoperative neurological course. To the best of our knowledge, this is the first report of the use of intraoperative CEUS in a case of intramedullary hemangioblastoma.