[Efficacy of malleostapedotomy for congenital ossicular malformation and influencing factors of postoperative hearing outcomes].

Objective: To investigate the efficacy of malleostapedotomy (MS) in treating congenital ossicular malformations and analyze the influencing factors of postoperative hearing outcomes using ultra-high-resolution computed tomography (U-HRCT). Methods: Patients with ossicular malformation who underwent MS surgery in the Center of Otolaryngology Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University from January 2015 to August 2024 were retrospectively included. Based on U-HRCT, the thickness of the stapes footplate or the oval window atresia plate and the angle and depth of Piston inserted into the vestibule were measured, and their correlations with postoperative efficacy were analyzed. Results: A total of 25 patients (26 ears) aged 15 (9, 27) years were included, with 15 males and 10 females. The average pure tone postoperative air-bone gap (ABG) of the 26 ears was lower than preoperative ABG [(22.7±10.1) decibels hearing level (dB HL) vs (44.8±12.0) dB HL, P<0.001]. Among them, eight ears underwent U-HRCT after the surgery. The measurement results showed that there was no correlation between postoperative ABG and the depth of Piston insertion (r=-0.061, P=0.885). Postoperative ABG was not correlated with the angle of Piston insertion (r=0.239, P=0.569). There was no correlation between postoperative ABG and the thickness of the stapes footplate or the atresia plate (r=0.099, P=0.852). The preoperative and postoperative bone conduction threshold (BC) was positively correlated with the thickness of the stapes footplate or the atresia plate (r=0.903, P=0.014; r=0.907, P=0.013). The preoperative and postoperative air conduction threshold (AC) was not correlated with the thickness of the stapes footplate or the atresia plate (r=0.167, P=0.752; r=0.732, P=0.098). Conclusions: MS surgery has a safe and reliable curative effect on patients with congenital ossicular malformations. As long as the insertion depth and angle of Piston are within a certain reasonable range, their impact on postoperative hearing is not significant. There is a correlation between the thickness of the stapes footplate or the oval window atresia plateand the bone conduction threshold.