The usefulness of external marking in stenting for m1 segment of middle cerebral artery stenosis. Technical note

In intracranial stenting procedures, especially for a focal stenosis on the M1 portion of the middle cerebral artery, the anatomical configuration of the middle cerebral artery is changed with the advance of a rigid stent catheter. Therefore, the location of the stenotic portion where the stent is supposed to be deployed, according to pre-measurements on the roadmapping image, could be changed to some degrees. To prevent this error, we put a 30 gauge needle with cap at the orbital rim on the same preliminary vertical line of the distal end of the stenotic portion where the distal end of the stent is supposed to be deployed and the stent deployment is performed under guidance of the external marking on the fluoroscopic image not under roadmapping image.We report our experience of successful elective stenting of middle cerebral artery stenosis using the aid of external marking.