Pitfall of Intraoperative Microvascular Doppler Sonography for Confirming the Complete Occlusion of Aneurysm / 대한뇌혈관외과학회지

OBJECTIVE: It is mandatory to optimaze clip placement in situ for complete clipping of cerebral aneurysm. Intraoperative microvascular doppler sonography (MDS) provides a functional and non-invasive intraoperative examination of the aneurysm proper. The present study was performed to investigate the reliability of MDS for assessing the complete aneurysm closure. METHODS: Blood flow velocities in the aneurysm sac were determined by MDS with a 20-MHz probe before and after aneurysm clipping, to confirm the obliteration of aneurysm since 1997. Complete aneurysm obliteration was confirmed by absent flow patterns in the domes of all aneurysms after clipping. RESULTS: The 1 mm microprobe was able to insonate all vessels and their major branches. The immediate adjustment of aneurysm clip placement or another clipping was done because hemorrhage after puncturing of completely clipped aneurysms on MDS developed in five patients including 3 middle cerebral artery aneurysms, 1 posterior communicating artery aneurysm, and 1 anterior communicating artery aneurysm. CONCLUSIONS: MDS is safe and cost-efficient for evaluation of aneurysm obliteration. In many cases, it can preclude the need of postoperative angiogram. However, although an intra-aneurysmal flow velocity is absent on MDS, it is necessary to puncture or cut the aneurysm sac if that is not shrunken after clipping, especially in cases of a complex aneurysm with a broad irregular base and atherosclerotic or thrombotic sac.

Role of Intraoperative Microvascular Doppler Sonography in the Surgery of Cerebral Aneurysm

The authors measured flow velocity of intracranial arteries to venrify the patency of the parent arteries and branches after clip placement during aneurysm surgery. Before the clinical study, experimental sonographic recording was done with a feline aorta. The patency was evaluated by recording the flow velocity and pulse waveform using intraoperative microvascular Doppler sonography. The results of the clinical study were summarized as follows: (1) The patency of the parent artery can be proved. (2) The complete clipping of aneurysmal sac can be confirmed. (3) Vasospasm or narrowing of the arterial caliber can be detected. (4) Severe arteriosclerosis may mimic decreased flow velocity. It is suggested that the use of intraoperative microvascular Doppler sonography is an atraumatic and reliable method of testing the optimal clipping of the aneurysm and patency of the parent artery.