Intraoperative microvascular Doppler in intracranial aneurysm surgery

Objective: The usefulness of intraoperative microvascular Doppler (IMD) in preventing an incorrect placement of the clip during intracranial aneurysm surgery is described. Such incorrect placement of the clip may cause new bleeding or ischemic accident as a consequence of incomplete exclusion of the aneurysm or stenosis/occlusion of the parent and/or adjacent arteries. Methods: One hundred thirty patients, harboring 136 aneurysms, were operated on using IMD. IMD study was performed on the aneurysm and adjacent arterial vessels before and after the clip placement. Mechanical arterial spasm was treated by topical sodium nitroprusside (SNP) and its efficacy verified by IMD. Results: In 55 aneurysms (42.3%), IMD was helpful in understanding the microvascular anatomy before clip placement. Complete exclusion resulted in 129 aneurysms (94.9%). In 5 cases (3.7%) in which IMD revealed a persistent blood flow in the aneurysm, the clip was repositioned. In 2 cases (1.4%), we obtained false-negative results. In 25 cases (18.3%) in which IMD data documented a severe flow reduction in the vessel harboring the aneurysm or in the vessel originating very close to the aneurysm neck, the clip was repositioned. There were no complications due to the use of IMD. In 20 patients (15%) in which IMD revealed arterial spasm by surgical manipulation, topical SNP was followed by resolution of the spasm. Conclusion: IMD is a feasible, safe, and very reliable technique in aneurysm surgery. Compared to other procedures such as intraoperative angiography, the cost efficiency of IMD is favorable.