括约肌

例句：

1. 1. The doctor performed a sphincterotomy to relieve the patient's pain.
   医生进行了括约肌切开术以缓解病人的疼痛。
2. 2. He was unable to perform the sphincterotomy due to his age.
   由于年龄的原因，他无法进行括约肌切开术。
3. 3. The surgery involved the removal of the sphincterostomy to prevent further complications.
   手术包括切除括约肌以防止进一步并发症。