Aeration following Intact Canal Wall Mastoidectomy

This study examines the prevalence and extent of re-aeration of the mastoid cavity following intact canal wall (ICW) mastoidectomy. Temporal bone computed tomography scans from patients with prior unilateral ICW mastoidectomy were identified. Three-dimensional volume reconstruction of the temporal bone was performed to measure aeration bilaterally. Thirty-five scans were analyzed; 16 (46%) showed good aeration in the operated ear and 19 showed poor aeration. The aeration (volume) in the surgical ears and the contralateral ears was significantly less than that in subjects without a history of ear disease. Those with poor aeration were more likely to require additional surgery. For temporal bone pairs with greater volume in the operated ear, the average difference was 1.3 cm³. Surgical creation of a mastoid cavity does not produce a large increase in aeration as compared with the contralateral ear. Following surgery, mastoid opacification may presage recurrent disease. Routine use of mastoidectomy in an attempt to improve aeration is not advocated.