(A837) Incus-Footplate Assembly: Surgical Outcome and Prognostic Factors

Introduction: Incus-Footplate Assembly (IFA) is an ossiculoplasty in patients missing stapes supra-structure with a mobile footplate in which an incus long process is preserved. In this study, the authors review the long-term hearing outcomes and analyze the prognostic factors.

Methods: The medical records of 17 subjects who received IFA (2003~2021) were retrospectively reviewed, including the history of previous ipsilateral ear surgery, presence of Carhart Notch, intraoperative incus status, and diagnosis (conductive hearing loss due to congenital versus inflammatory causes). Audiometric preoperative and postoperative data were reviewed along with intraoperative findings. Analyses of postoperative air-bone gap (ABG) and postoperative AC-preoperative BC (ABG-e) were done.

Results: The mean preoperative and postoperative ABG were 32.3 ± 8.2 and 16.0 ± 12.6 dB, respectively. The mean ABG-e was 9.6 dB (range, -2.5 to 35.8 dB). Thirteen (76.5%) patients had an optimal outcome of ABG-e ≤ 10 dB. Treatment outcomes were comparable across different age groups. The history of previous ipsilateral surgery was related to bigger postoperative ABG, specifically in the lower frequencies. Patients without Carhart Notch in preoperative audiometry had better treatment outcomes, with smaller ABG across all frequencies, including ABG-e. Patients with incus anomaly had bigger postoperative ABG in lower frequencies but were comparable with patients with normal incus status in higher frequencies. ABG was bigger in patients with a congenital cause compared to inflammatory conditions across all frequencies, including ABG closure. A significant association was also observed between the absence of stapes fixation and obtaining the best post-operative ABG closure ≤ 10 dB (p=.035).

Conclusions: IFA showed excellent treatment outcomes, with most patients achieving the best results of ABG-e ≤ 10 dB. Patients with preoperative absence of Carhart Notch on audiometry, normal intraoperative incus status, no history of previous ipsilateral ear surgery, and inflammatory causes than congenital etiology showed favorable outcomes.