Anatomical and frequencies-specific hearing results of retrograde mastoidectomy.

Purpose: The aim of this study was to evaluate the long-term anatomical and frequency-specific hearing results of canal wall down (CWD) and canal wall up (CWU) mastoidectomy by retrograde mastoidectomy (RM) surgical method.
Materials and Methods: Patients underwent CWU and CWD procedures with method of RM, 53 and 59 patients between January 2010 and June 2015 were evaluated retrospectively. The pre- and post-operative pure tone average air-bone gap (ABG) values of these patients were recorded in detail at 0.5, 1, 2 and 4 kHz. Pre and post-operative ABG were evaluated in detail in each group in each frequency. In addition, at least two years follow-up recurrence rates were evaluated.
Results: In the CWU method, post-operative ABG decreased significantly at low-frequencies compared to pre-operative ABG (p < 0.05), especially at 2 kHz (p < 0.001). But, auditory improvement was not achieved at 4 kHz. In the CWD procedure, auditory improvement was not achieved both 1 kHz and 4 kHz. CWU and CWD recurrence rates were respectively 9.4% and 10.1%.
Conclusion: Postoperative hearing results of both surgical methods provide good auditory outcome at low-frequencies. This improvement is evident in CWU especially at 2 kHz. This may be related to the protection of the external ear canal. In both surgical methods of RM, a satisfactory anatomical success was achieved with recurrence rates of around 10%. RM is a good surgical technique alternative to classical canal wall down procedure with both auditory results and low recurrence rates.
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