To prevent the infection from spreading, the doctors decided to perform an amputation of the arm.

amputation 是名词，来自动词 amputate（截肢）。amputate 由前缀 am-（表示"周围、切除"）和拉丁词根 putare（意为"修剪、清理"）组成，字面意思是"切除周围部分"。amputation 指"通过手术切除身体部位（通常是肢体）"的医疗行为。