infective stricture of eustachian tube

例句：

1. 1. The infective stricture of the eustachian tube is a common cause of middle ear infections.
   中耳感染的常见原因是鼓膜下狭窄。
2. 2. Infections can lead to severe complications if left untreated, including an infective stricture.
   如果未治疗，感染可能导致严重并发症，包括感染性狭窄。
3. 3. Surgery is often necessary to relieve the infective stricture and prevent further damage to the eardrum.
   手术通常必要以缓解感染性狭窄并防止进一步损害鼓膜。