Anatomical and frequencies-specific hearing results of retrograde mastoidectomy

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.

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.

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%.

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.