Helical insertion infusion device

1. A system for delivering fluid to a user transcutaneously, the system comprising:

a base assembly configured to be located on the user's skin;

a flexible subcutaneous infusion cannula configured to be wound fully within the base assembly prior to insertion;

an inserter assembly coupled to the base assembly, the inserter assembly being configured to drive the wound flexible subcutaneous infusion cannula from the base assembly through the user's skin at an angle of less than 45° in a nominally helical trajectory; and

a fluid connection assembly configured to fluidically connect the base assembly to a source of delivery fluid.

2. The system of claim 1 , wherein the inserter assembly is removably coupled to the base assembly.

3. The system of claim 1 , further comprising a sharp inner stylet configured to extend through the flexible subcutaneous infusion cannula.

4. The system of claim 3 , wherein the sharp inner stylet has a pre-set curved shape.

5. The system of claim 3 , wherein the inserter assembly includes an automatic retraction mechanism configured to move the sharp inner stylet from an advanced position to a retracted position after completion of a cannula insertion cycle.

6. The system of claim 5 , wherein the inserter assembly includes an automatic release mechanism configured to decouple the inserter assembly from the base assembly after completion of a stylet retraction cycle.

7. The system of claim 6 , wherein the inserter assembly is configured to automatically perform the cannula insertion cycle, the stylet retraction cycle and a release cycle in succession after a single trigger event without further interaction from the user.

8. The system of claim 7 , wherein the inserter assembly includes a single drive spring configured to supply all energy required to drive the cannula insertion cycle, the stylet retraction cycle and the release cycle.

9. The system of claim 1 , wherein the base assembly includes an adhesive on at least one surface thereof configured to attach the base assembly to the user's skin.

10. The system of claim 1 , wherein the flexible subcutaneous infusion cannula includes an outer tube and an inner reinforcement coil.

11. The system of claim 1 , wherein the flexible subcutaneous infusion cannula includes two or more fluid exit holes at or near the distal end thereof.

12. The system of claim 1 , wherein the system further comprises packaging for enclosing at least the inserter assembly before use, the packaging including a rotational element, wherein the inserter assembly includes at least one torsion drive spring, and wherein the inserter assembly is configured to automatically charge the drive spring as the rotational element is rotated to open the packaging.

13. The system of claim 1 , wherein the fluid connection assembly includes tubing and an element or assembly that changes color when the tubing has been primed with fluid.

14. The system of claim 1 , wherein the fluid connection assembly includes a releasable fluid interconnect assembly configured to releasably connect the base assembly to the source of delivery fluid, and wherein the source of delivery fluid is external to the base assembly.

15. The system of claim 14 , wherein the releasable fluid interconnect assembly includes a needle and a septum, wherein the fluid interconnect assembly is configured to insert an end of the needle through the septum after a cannula stylet is withdrawn from the septum.