Introduction: The outcome of surgical treatment of cerebral aneurysms may be severely impaired by local ischaemia, or by infarction resulting from the inadvertent occlusion or stenosis of a parent vessel or its distal branches. Incomplete aneurym occlusion, on the other hand, increases the risk of haemorrhage. Despite great attempts to preserve patency at the time of clip application, intraoperative visual observation may not reveal arterial compromise or occlusion. It is therefore of the utmost importance that both aneurysm occlusion and inadvertent clipping of neighbouring vessels be avoided during the surgical act.

Methods: This article has two major aims: to review the cerebral hemodynamic changes with aneurysms, and to indicate and compare intraoperative monitoring techniques:intraoperative angiography(IOA),indocyanine green angiography (ICG),intraoperative microvascular Doppler(IMD) during cerebral aneurysm surgery.

Results: The time taken for an IOA in aneurysm surgery varied from 30 min to 45 min.IOA carries the risk of arterial injury or stroke and its widespread availability is limited.In patients with large or giant, wide-neck aneurysms or with thick-walled atherosclerotic vessels, the ICG may be unreliable. In many patients, the availability of this tool has obviated the need for intraoperative catheter-based angiography, but a limitation of ICG is that it is only useful in the assessment of brain vessels along the line of sight of the microscope. The Doppler microprobe was placed with an insonation angle of 30–60 degrees. The mean duration of IMD investigations was 5.3 minutes. There were no complications of intraoperative microvascular Doppler probe use.

Conclusions: After placement of the permanent clip on the aneurysmal neck, non-invasive IMD, ICG,or invasive IOA are employed to assess the patency of the parent artery as well as the entire occlusion of the aneurysm neck.It is recommended that IMD be used routinely in cerebral aneurysm surgery, especially in those large and giant aneurysms with wide neck or without neck.

Patient Care: It is recommended that IMD be used routinely in cerebral aneurysm surgery, especially in those large and giant aneurysms with wide neck or without neck. This technique is a valuable tool, instead of intraoperative angiography for the surgical treatment of aneurysms.

Learning Objectives: Qualitative analysis and quantitative analysis measurement of blood flow in cerebral vessels during aneurysm surgery can help prevent ischaemia and improve patient outcome. The present study was performed to investigate the reliability and practicability of intraoperative monitoring techniques during cerebral aneurysm surgery, and to assess the influence of this method on the surgical procedure.

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