Intra-operative colour-duplex-sonography in the surgical management of cerebral AV-malformations

In this prospective study the role of intra-operative Colour-Duplex-Sonography (= CDS) during surgery of arteriovenous malformations (= AVM) is evaluated. During the last three years 20 consecutive patients with supratentorial AVMs were examined by intra-operative CDS in order to evaluate the potential of CDS to 1) localize the AVM, 2) differentiate between embolized and perfused parts, 3) identify feeding and draining vessels and 4) control the complete excision of the AVM. All AVMs were localized supratentorially, 9 were grade I and II (according to Spetzler and Martin [31]), 8 grade III and 3 grade IV. 11 were partly embolized and 8 associated with an intracerebral bleeding. In all cases the nidus was correctly localized sonographically by its typical bidirectional flow pattern in Colour-mode. CDS guided the surgeon directly to all (11 cases) deep-seated AVMs (2 to 4 cm subcortically). The smallest nidus measured 10 mm. 28 of 34 angiographically defined main feeding and 18 of 23 draining vessels were identified. 14 patients were controlled sonographically at the end of the resection regarding the completeness of excision. In 11 patients CDS was negative and was confirmed by either postoperative angiography or MRI in 10 patients. In one case residual AVM tissue was missed by CDS. Positive CDS findings in 3 cases were all confirmed by microscopic re-inspection, angiography and CCT. Our results suggest that CDS is able to localize AVMs intra-operatively with minimal instrumentation. It allows safe navigation to deep-seated malformations with high accuracy. Feeding and draining vessels can be identified and completeness of resection can be controlled.