Combined needle and cannula

A method of performing an injection on a patient, the method comprising:

• attaching a syringe to a syringe holder of an injection device;
• inserting a sharp tip of a needle of the injection device together with a blunt tip of a cannula of the injection device through an epidermis and at least partially through a dermis of the patient, wherein the needle is mounted over the cannula;
• retracting the needle over the cannula to remove the sharp tip from the patient and position the sharp tip within a needle guard of the injection device, while maintaining a position of the blunt tip of the cannula in or below the dermis;
• advancing the cannula to a target location in or below the dermis;
• injecting a substance from the syringe through the cannula to the target location;
• and
• removing the cannula from the patient.

A device for performing injections in a patient, the device comprising:

• a needle having a sharp tip and an inner diameter;
• a cannula having a blunt tip, a cannula hub for connecting with a syringe, a length that is longer than that of the needle, and an outer diameter that is smaller than the inner diameter of the needle;
• and
• a needle guard for shielding the needle when it is retracted.