Intraoperative microvascular Doppler ultrasonography in cerebral aneurysm surgery

Objectives-Outcome of surgical treatment of cerebral aneurysms may be sever ely compromised by local cerebral ischaemia or infarction resulting from th e inadvertent occlusion of an adjacent vessel by the aneurysm clip, or by i ncomplete aneurysm closure. It is therefore mandatory to optimise clip plac ement in situ to reduce the complication rate. The present study was perfor med to investigate the reliability of intraoperative microvascular Doppler ultrasonography (MDU) in cerebral aneurysm surgery, and to assess the impac t of this method on the surgical procedure itself. Methods-Seventy five patients (19 men, 56 women, mean age 54.8 years, range 22-84 years) with 90 saccular cerebral aneurysms were evaluated. Blood flo w velocities in the aneurysmal sac and in the adjacent vessels were determi ned by MDU before and after aneurysm clipping. The findings of MDU were ana lysed and compared with those of visual inspection of the surgical site and of postoperative angiography. Analysis was also made of the cases in which the clip was repositioned due to MDU findings. Results-A relevant stenosis of an adjacent vessel induced by clip positioni ng that had escaped detection by visual inspection was identified by Dopple r ultrasonography in 17 out of 90 (18.9%) aneurysms. In addition, Doppler u ltrasound demonstrated a primarily unoccluded aneurysm in 11 out of 90 (12. 2%) patients. The aneurysm clip was repositioned on the basis of the MDU fi ndings in 26 out of 90 (28.8%) cases. In middle cerebral artery (MCA) aneur ysms, the MDU results were relevant to the surgical procedure in 17 out of 44 (38.6%) cases. Whereas with aneurysms of the anterior cerebral artery si gnificant findings occurred in only five of 32 cases (15.6%; p<0.05). The c lip was repositioned on the basis of the MDU results in 18 out of 50 (36%) aneurysms in patients with subarachnoid haemorrhage (SAH) grade I-V compare d with only eight out of 40 (20%) aneurysms in patients without SAH (p<0.05 ). Conclusions-MDU should be used routinely in cerebral aneurysm surgery, espe cially in cases of MCA aneurysms and after SAH. Present data show that a po stoperative angiography becomes superfluous whenever there is good visualis ation of the "working site" and MDU findings are clear.