Learning Objectives: The aim of this study is to investigate causes and treatment results of revision surgery cases performed after CWD tympanomastoidectomy.

Canal wall down (CWD) tympanomastoidectomy may be an appropriate choice for the successful removal of cholesteatoma in the middle ear, attic, and mastoid cavity. However, it sometimes needs some revision surgeries. The aim of this study is to investigate causes and treatment results of revision surgery cases performed after CWD tympanomastoidectomy.From Jan 2010 to Dec 2015, among 276 patients who underwent CWD tympanomastoidectomy, cases requiring revision surgery were enrolled in this study. Six cases of staged operations and 18 patients who were not followed up more than 6 months were excluded in this analysis. Using medical records, demographics of subjects, causes of revision surgery, operation name, and postoperative results were investigated retrospectively. Patients were divided into 2 groups according to whether they had got an intact canal wall mastoidectomy as the initial surgery.Among 252 patients, 18 (7.1%) needed revision surgeries due to postoperative problems excluding staged operations and minor procedures. Male to female ratio was 6:12 and left to right ratio 10:8. Residual cholesteatoma was found in 3 cases (1.2%) and they were removed in sinus tympani (2 cases) and malleus handle (1 case) successfully. There was no more cholesteatoma recurrence after revision surgery. Tympanoplasty or myringoplasty was performed in 15 cases (6.0%) and the perforation of tympanic membrane was healed in all cases. Revision ossiculoplasty due to prosthesis extrusion was done in 1 case (0.4%). Final postoperative outcomes showed no statistical significance between two groups (p > 0.05). Revision surgeries after CWD tympanomastoidectomy showed a low incidence and good postoperative outcomes. However, regular and careful examinations after initial surgery should be emphasized to avoid revision surgery.