Which of the following operations is defined as the act of putting something into a space or cavity?

The operation defined as the act of putting something into a space or cavity is indeed introduction. In the context of ICD-10-PCS coding, introduction refers to the process of placing a device or substance into an anatomical site, typically through an orifice or puncture, without any incision on the skin. This is an important differentiation within coding, as it indicates that something external is being inserted rather than altered or removed from the body.

Other operations such as removal and excision involve extracting materials or tissues from the body, which is conceptually the opposite of introduction. Resection refers specifically to the surgical removal of a portion of an organ or tissue, further emphasizing the distinction between entering or adding to a space versus taking away from it. Understanding these definitions ensures accurate coding and documentation of surgical procedures and their intents.