Assessment of flow in perforating arteries during intracranial aneurysm surgery using intraoperative near-infrared indocyanine green videoangiography

OBJECTIVE: Perforating arteries are commonly involved during the surgical dissection and clipping of intracranial aneurysms. Occlusion of perforating arteries is responsible for ischemic infarction and poor outcome. The goal of this study is to describe the usefulness of near-infrared indocyanine green videoangiography (ICGA) for the intraoperative assessment of blood flow in perforating arteries that are visible in the surgical field during clipping of intracranial aneurysms. In addition, we analyzed the incidence of perforating vessels involved during the aneurysm surgery and the incidence of ischemic infarct caused by compromised small arteries. METHODS: Sixty patients with 64 aneurysms were surgically treated and prospectively included in this study. Intraoperative ICGA was performed using a surgical microscope (Carl Zeiss Co., Oberkochen, Germany) with integrated ICGA technology. The presence and involvement of perforating arteries were analyzed in the microsurgical field during surgical dissection and clip application. Assessment of vascular patency after clipping was also investigated. Only those small arteries that were not visible on preoperative digital subtraction angiography were considered for analysis. RESULTS: The ICGA was able to visualize flow in all patients in whom perforating vessels were found in the microscope field. Among 36 patients whose perforating vessels were visible on ICGA, 11 (30%) presented a close relation between the aneurysm and perforating arteries. In one (9%) of these 11 patients, ICGA showed occlusion of a P1 perforating artery after clip application, which led to immediate correction of the clip confirmed by immediate reestablishment of flow visible with ICGA without clinical consequences. Four patients (6.7%) presented with postoperative perforating artery infarct, three of whom had perforating arteries that were not visible or distant from the aneurysm. CONCLUSION: The involvement of perforating arteries during clip application for aneurysm occlusion is a usual finding. Intraoperative ICGA may provide visual information with regard to the patency of these small vessels.

Empowering Interactions. Political Cultures and the Emergence of the State. in Europe 1300-1900

The emergence of the state in Europe is a topic that has engaged historians since the establishment of the discipline of history. Yet the primary focus of has nearly always been to take a top-down approach, whereby the formation and consolidation of public institutions is viewed as the outcome of activities by princes and other social elites. Yet, as the essays in this collection show, such an approach does not provide a complete picture. By investigating the importance of local and individual initiatives that contributed to state building from the late middle ages through to the nineteenth century, this volume shows how popular pressure could influence those in power to develop new institutional structures. By not privileging the role of warfare and of elite coercion for state building, it is possible to question the traditional top-down model and explore the degree to which central agencies might have been more important for state representation than for state practice. The studies included in this collection treat many parts of Europe and deal with different phases in the period between the late middle ages and the nineteenth century. Beginning with a critical review of state historiography, the introduction then sets out the concept of 'empowering interactions' which is then explored in the subsequent case studies and a number of historiographical, methodological and theoretical essays. Taken as a whole this collection provides a fascinating platform to reconsider the relationships between top-down and bottom-up processes in the history of the European state.