PMC9168310_01
Preoperative imaging. (a and b) Head computed tomography scan. A (noncontrast acquisition): bilateral cSDH (red asterixis) and left extra-axial structures suspected to be abnormal vessels (blue arrow). (b) (Maximum Intensity Projection [MIP] reconstruction from CT angiography): the structures are identified as dilated cortical veins (blue arrow). C (left middle meningeal artery [MMA] digital subtracted angiography [DSA], lateral view): dAVF depending on frontoparietal and squamo-occipital MMA branches (respectively, FPb and SOb). The shunt (red circle) is directly on a tortuous left parietal cortical vein (blue arrows) with secondary drainage within the superior longitudinal sinus (Cognard Type III dAVF). The foramen spinosum (white dotted circle) and the temporal artery (white arrow) are depicted as anatomical landmarks.
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F1
Digital subtraction angiography confirmed these to be a dAVF, fed bilaterally by parieto-occipital branches of the middle meningeal artery (MMA) draining directly into a unique dilated left parietal cortical vein without venous ectasia and secondary drainage within the superior longitudinal sinus (Cognard Grade 3) [Figure 1].
Intraoperative images of different stages of the operation (A-D) and postoperative imaging. (a) Turgescent dural vessels. (b) Intradural view of turgescent veins located within a group of parasagittal calcifications. (c) Transient clipping of the posterior vein: deflation and color change indicating the dearterialization of the draining veins. (d) Clipping and division of the coagulated vein with macroscopic normalization of the venous system. (e) (Lateral view of postoperative MMA DSA, 18 days): no residual early venous opacification. Now that the shunt has been disconnected, the occipital component of the SOb is more clearly observed. The proximal part of the FPb had been occluded during the embolization attempt. The localization of the craniotomy flap (back dotted lines), the foramen spinosum (white dotted circle), and the temporal artery (white arrow) are depicted as anatomical landmarks. (f) (Noncontrast CT, 34 days): regression of the left SDH (red asterisk).
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F2
The deflated draining vein's color changed, as expected, from bright red to dark purple [Figure 2] and intraoperative Doppler confirmed the disappearance of arterial-type flow within those vessels. Follow-up angiography showed no persisting shunt and follow-up CT the regression of the subdural hematoma over the following months [Figure 2].