Bone-conduction threshold and air-bone gap may predict frequency-specific air-conduction threshold after tympanoplasty

Abstract

Postoperative hearing improvement is one of the main expectations for patients receiving tympanoplasty. The capacity to predict postoperative hearing may help to counsel a patient properly and avoid untoward expectations. It is difficult to predict postoperative hearing without knowing the disease process in the middle ear, which can only be assessed intraoperatively. However, the duration and extent of the underlying pathologies may represent in bone-conduction threshold and air-bone gap. Here in patients undergoing tympanoplasty without ossiculoplasty, we sorted and separated the surgery dates into the first group to build the predicting models and the second group to test the predictions. There were 87 and 30 ears, respectively. No specific enrollment or exclusion criteria were based on underlying pathologies such as the perforation size of the tympanic membrane or the middle ear conditions. The results show that bone-conduction threshold and air-bone gap together predicted air-conduction threshold after the surgery, including each frequency of 0.5k, 1k, 2k, and 4k Hz. The discrepancies between the predictions and recordings did not differ among these four frequencies. Of the variance in mean postoperative air-conduction threshold, 56.7% was linearly accounted for by these two preoperative predictors in this sample. The results suggest a trend that, the higher the frequency, the larger the part was accounted for by these two preoperative predictors. These together may help a surgeon to estimate frequency-specific hearing outcome after the surgery, answer patients’ questions with quantitative statistics, and counsel patients with proper expectations.

Shifting from postauricular to transcanal microscopic tympanoplasty may have similar frequency-specific improvements with better air-bone-gap closure at low frequencies and a minimal learning-curve effect

“…A known underlying pathology is not necessarily linked to a specific hearing outcome [ 15 ]. Our earlier work [ 16 ] and that of Szaleniec, J. et al [ 17 ] has shown that bone-conduction threshold and air-bone gap may predict frequency-specific air-conduction threshold after tympanoplasty. The hearing before surgery is associated with hearing after surgery, regardless of anatomy [ 18 ].…”