Mastoid Obliteration in Acquired Cholesteatoma, Importance and Evolution of Surgical Technique Used in Epitympanic Separation of the Middle Ear

OBJECTIVE: To determine the effect of the obliteration technique applied to divide the epitympanum from the middle ear during cholesteatoma surgery on the recurrence of cholesteatoma. STUDY DESIGN: Retrospective cohort study in a tertiary referral center. PATIENTS: All patients undergoing cholesteatoma surgery from 2010 until 2023 were included. 116 pediatric cases, 286 adults. One hundred forty-two were primary surgeries, 260 revision procedures. INTERVENTION: Canal wall up mastoidectomy and obliteration of the epitympanum and mastoid using different techniques. MAIN OUTCOME MEASURES: Recurrence rates and timing of recurrence during follow-up. RESULTS: The overall recurrence rate was 11.69% (median FU 4.3 y, range: 0.02 to 12 y). The recurrence rates differed significantly among the 5 different techniques of obliteration: 100% after obliteration with bone pâté (median FU 3.3 y), 21% after a hybrid technique (median FU 2.5 y), 18% after cartilage (median FU 5.6 y), 10% after midtemporal artery flap (MTF, median FU 4.7 y), and 0% after an avital flap (median FU 0.6 y, range up to 11 y). When correcting for FU length, the statistically significant difference persisted in the Kaplan-Meier survival curves. CONCLUSIONS: To lower recurrence rates in canal wall up surgery with obliteration, the focus should lie in creating a complete and smooth separation of the middle ear from the epitympanum. Currently, the most favorable results are found when this separation is created with a vital MTF or an avital flap, followed by hydroxyapatite to fill up the rest of the epitympanic space and mastoid. This effect is independent of possible confounders such as age of the patient and different surgeons. The short FU for the current technique is a limitation; longer FU is needed to reliably confirm whether it reduces recurrent disease more effectively than previous techniques.