Abstract: A surgical dilator for dilation of cerebral tissue, having an outer needle, an inner needle insertable into the outer needle and an expandable sac attached to the outer needle, which permits access to a tumor, cerebral ventricle or other tissue by dilating the cerebral tissue in its path and indicates when such tumor, ventricle or other tissue has been entered by the release of fluid through the outer needle. Also, a method of verifying entry into a tumor, ventricle or other tissue and creating a bloodless opening to such tumor, ventricle or other tissue in cerebral tissue utilizing the surgical dilator.