These needles are mainly used in the civilian medical world to create a permanent means of entry to a vein or artery, so that drugs may be given intravenously to a patient at any time without having to puncture the patient's skin repeatedly.

The cannula needle is inserted into skin, into the vein or artery, and the cannula (sleeve) held in place while the needle is withdrawn. This creates a stable, semipermanent tube through which fluids and small surgical instruments may be introduced.

As they relate to body modification, cannula needles are used (mainly in Europe; North American piercers generally do not use cannula needles) because they leave a stable route through which jewelry can be inserted. They make the introduction of jewelry easier as the jewelry does not have to be held tight against the end of the needle as the needle is drawn through the piercing site.

An interesting note is that when using "normal" non-cannula needles, the jewelry is inserted through the piercing site in the same direction as the needle was inserted. When using a cannula needle, the jewelry is inserted in the opposite direction to the direction in which the needle was inserted.

This means that both cannula and non-cannula needles have different benefits when used to pierce different areas of the body; using one type instead of the other may make certain piercings easier to perform.