PMC4258723_01
Schema of the timing of imaging and surgery. (a) CT image obtained at onset showing subarachnoid hemorrhage. (b) Three-dimensional digital subtraction angiography (3D-DSA) showing an irregular-shaped aneurysm on the right posterior communicating artery (white arrow). (c) Follow-up 3D-DSA showing enlargement of the aneurysm (white arrowhead). (d) Postoperative 3D-DSA showing reduction of the aneurysm (double white arrowheads). (e) Follow-up three-dimensional CT angiography (3D-CTA) after 4 years showing further reduction of aneurysm
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Coma Scale (E3V5M6), and no weakness was observed in her extremities. Computed tomography (CT) demonstrated subarachnoid hemorrhage [SAH; Figure 1a]. The blood flow to the right MCA territory came mainly from the right posterior cerebral artery (PCA) through the enlarged PCoA, and an irregular-shaped aneurysm was found on the right PCoA [Figures 1b and 2b, c]. Repeated DSA did not demonstrate vasospasm, but demonstrated enlargement of the aneurysm [Figure 1c]. The size and shape of the aneurysm appeared to be reduced [Figure 1d]. Three-dimensional CT angiography performed 4 years after surgery demonstrated further reduction of the aneurysm [Figure 1e].
DSA before (a-d) and after surgery (e-f). (a) The right CCA occluded at its origin (arrow). (b, c) The blood flow to the right MCA territory originated mainly from the right PCA through the enlarged PCoA. The left ICA aneurysm had been completely clipped. (d) The blood flow from VA to OA (through the dilated muscle branches) had reversed toward ECA and the carotid bifurcation (white arrowhead). (e, f) The bypass was patent (arrow head). (g, h) The flow through the PCoA finally directed to the cortical artery of the distal M1, preserving the flow of M1 and its perforators (double arrows)
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Emergent digital subtraction angiography (DSA) revealed that the right CCA was occluded at its origin [Figure 2a]. The blood flow to the right MCA territory came mainly from the right posterior cerebral artery (PCA) through the enlarged PCoA, and an irregular-shaped aneurysm was found on the right PCoA [Figures 1b and 2b, c]. A right vertebral artery (VA) injection also detected collateral blood flow from the VA to the OA (through the dilated muscle branches) that had reversed toward the right external carotid artery (ECA) and the carotid bifurcation [Figure 2d]. The left ICA aneurysm had been completely clipped [Figure 2c]. Postoperative DSA revealed sufficient bypass flow perfusing the MCA territory and extremely reduced collateral flow through the PCoA [Figure 2e-h]. This flow directed to the cortical artery of the distal M1 as designed during the operation, preserving the flow of the M1 and its perforators [Figure 2g, h].
The diagram of surgical flow reduction. The radial artery graft was anastomosed to the M2, and the M1 segment was obliterated with two Sugita Elgiloy clips just distal to bifurcation of the cortical branch. The opposite side of the radial artery graft was anastomosed to the dilated muscle branch of the occipital artery. AchoA: Anterior choroidal artery; LSA: Lenticulostriate artery
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The strategy consisted of (i) OA-RA free graft-MCA bypass and (ii) subsequent obliteration of the distal M1 portion of the right MCA with a clip [Figure 3]. The M1 was then obliterated with two Sugita Elgiloy clips just distal to this point, leaving the cortical branch proximally to function as a flow-outlet of the collateral flow through the PCoA [Figure 3].