What is bulge

expanded全称膨体聚四氟乙烯（ePTFE），内部有微孔，组织可长入其中，因此术后移位风险相对较低，触感也更接近自体组织。

comparative advantage

• High fit with tissue and more natural outline;

• Light weight and little pressure on the back of the nose;

• 长期稳定性较好。

Points to pay attention to

微孔结构也意味着对手术无菌要求更高，感染处理相对复杂；且一旦需取出，分离难度高于silica gel。是否选用应综合皮肤厚度、术式与医生建议。

Brief comparison with silicone

Silicone is easier to remove and is usually cheaper; expanded body fits more closely but the operating threshold is higher. Both need to be standardized and implanted by formal institutions.

material选择是专业决策，请面诊后确定。