[Therapeutic effect of β-tricalcium phosphate in mastoid cavity obliterationunder endoscope]

Objective:To investigate the therapeutic effect of β-tricalcium phosphate in mastoid cavity obliteration for middle ear cholesteatoma under endoscope. Methods:Sixty patients with middle ear cholesteatoma admitted to our department from September 2021 to March 2022 were included in this study. The observation group（n=30） received β-tricalcium phosphate during mastoid cavity obliteration. The control group（n=30） received autologous tissue during mastoid cavity obliteration. Pure tone audiometry was performed before surgery and after surgery in both groups, and the air conduction thresholds of 500, 1 000, 2 000 and 4 000 Hz were recorded. The external acoustic meatus cross-sectional area within 1 cm of the external acoustic meatus opening was measured during the operation and after the operation. The differences of postoperative ear drying time, hearing change and mastoid cavity healing were compared between the two groups. Results:The duration of postoperative dry ear in the observation group was 2-14 weeks, with an average of （9.4±2.7） weeks, while that in the control group was 4-26 weeks, with an average of（16.0±5.7） weeks. The difference in dry ear time between the two groups was statistically significant（P<0.05）. In the observation group, the threshold change was -19-27 dB, with an average of（6.4±10.7） dB, and in the control group, the threshold change was -9-17 dB, with an average of （4.7±7.1） dB. There was no significant difference in hearing change between the two groups（P>0.05）. In the observation group, the cross-sectional area of 1 cm inside the ear canal opening was -5.9-8.2 mm², with an average of （-0.6±2.6） mm², and in the control group, the cross-sectional area of 1 cm inside the ear canal opening was -5.5-5.2 mm², with an average of （-0.4±2.3） mm². There was no significant difference in intraoperative cavity changes between the two groups（P>0.05）. Conclusion:The application of β-tricalcium phosphate to fill the mastoid cavity during the operation of endoscopic middle ear cholesteatoma has no adverse effect on the hearing of patients, can shorten the postoperative dry ear time, and results in good postoperative healing, which is worth promoting.