After a brief historical outline of the radical operation of the ear, the possibilities are presented which are at our disposal to construct a mastoid cavity after removal of the posterior bony wall of the auditory canal, thus keeping the problems for the patient at a minimum. At best, a small self-cleansing well-designed cavity is formed under favourable conditions. Important prerequisites for the construction of such a cavity are: A good overview obtained by smoothening of the cavity walls; widening of the auditory canal entrance (cartilage excision); removal of excess bone covering the facial nerve; and reducing the size of the cavity by means of a Palva flap while preserving the postauricular artery and its larger branches. Postoperative management (and cleansing) must be done with an operation microscope.