Subchoroidal trans-velum interpositum approach to mid-third ventricular tumors.

Our experience with the subchoroidal, trans-velum interpositum approach to mid-3rd ventricular tumors is reviewed, and our operative technique is described. Excellent exposure of the mid-3rd ventricle is gained by opening the foramen of Monro posteriorly after dividing the septal vein and/or the thalamostriate vein from the ipsilateral internal cerebral vein. There has been no morbidity or mortality in eight successive cases. The principal advantage of this technique is that the fornix is preserved and memory function is not at risk.