After closed operation techniques recurrences of cholesteatoma are often caused by retraction of squamous epithelium under the bony annulus, under which it spreads into the attic or the mastoid cavity. Consequently, retractions under the bony annulus can be avoided, if the annulus is removed. An endaural operation technique is described in which the superior and posterior bony ear canal wall is completely removed and the posterior wall is reconstructed by means of a meatal skin flap. As the oval window is often partly hidden by the frame of the tympanic membrane it is more favourable for the restoration of the sound conducting mechanism if the frame and surface of the tympanic membrane are extended backwards. This can be done by repositioning the posterior cutaneous ear canal wall and grafting the tympanic membrane with fascia. By doing this, the attic is incorporated into the ear canal. Should the factors which originally induced the development of the cholesteatoma remain effective and cause a new retraction, the full breadth of the posterior ear canal skin will retract into the exenterated mastoid cavity. An easily accesible open cavity and not a recurrence will be the result. In a follow-up study of 112 patients it was found that 67 of them had developed such an open cavity, which caused no serious problems.