Analysis of factors affecting postoperative functional outcome in patients with otosclerosis

This study aimed to analyze the factors affecting postoperative hearing results of patients with otosclerosis.

Medical records of 245 patients with clinical otosclerosis who underwent stapes surgery at our center from January 2009 to December 2018 were reviewed. The retrospectively collected data included patients' demographics, clinical characteristics, pre- and postoperative audiometric data, size of preoperative air-bone gap (ABG) (small/large). The patients were categorized into two groups according to the postoperative functional outcome: Group 1 consisted of patients with a postoperative ABG of ≤10dB and Group 2 comprised those with a postoperative ABG of >10dB. Evaluation of factors affecting functional outcome were performed by logistic regression analysis. Receiver operating characteristics (ROC) curve was generated to obtain the cut-off points for preoperative ABG.

There were no statistically significant differences between the two groups in terms of age group (p=0.393), gender (p=0.670), operated side (p=0.370), and laterality of disease (p=0.607). There were 42 patients (31.6%) with a small ABG and 91 patients (68.4%) with a large ABG in group 1, and six (13.6%) and 38 patients (86.4%), respectively in group 2. There was a statistical significant difference between the groups in terms of the size of preoperative ABG (p=0.020). In group 1, the mean preoperative air conduction (AC) threshold and preoperative ABG were significantly lower than in group 2 (p<0.001 and p<0.001, respectively). There was no statistically significant difference between the groups in terms of the preoperative bone conduction (BC) threshold (p=0.406). Preoperatively, the AC threshold and large ABG were found to be significantly poorer prognostic factors (p<0.001; 95%CI: 1.031-1.210 and p=0.037; 95%CI: 1.063-7.023, respectively). Preoperative ABG cut-off threshold for functional success was found to be 34.5dB. The functional success rate was significantly higher in patients with a preoperative ABG of <34.5 than in patients with a preoperative ABG of ≥34.5dB (p<0.001).

The preoperative AC threshold and large ABG were poor prognostic factors for postoperative hearing outcome in patients with otosclerosis. The functional outcomes were similar in patients with a preoperative small ABG and those with a preoperative ABG of <34.5dB. A preoperative ABG cut-off value of <34.5dB should be possibly considered as a parameter for predicting surgical success in otosclerosis and seems to be useful in clinical practice.