Transcutaneous device assembly
A medical device is provided comprising a cannula having a distal portion adapted to be arranged through the skin of the subject, and an outer needle arranged coaxially with and being axially moveable relative to the cannula, the needle comprising a pointed distal end, wherein the device is adapted for advancing the cannula with the distal end of the needle projecting there from through the dermis of the subject, and subsequently retract the needle.
1. An assembly for insertion of a cannula, comprising:
a housing,
a needle comprising a distal portion adapted to be inserted through the skin of a subject,
a needle holder for moving the needle,
a flexible cannula comprising a distal portion adapted to be arranged subcutaneously in the subject, the distal portion of the cannula being arranged in sliding parallel relationship with the distal portion of the needle,
a cannula holder for moving the cannula relative to the needle,
the assembly having an initial state in which the needle holder and the cannula holder are each arranged in a respective first retracted position relative to the housing, and the needle and cannula are each arranged in a respective initial retracted position relative to the housing,
an actuator that moves each of the needle holder and the cannula holder to a respective first extended position relative to the housing, and moves each of the needle and the cannula to a respective extended position relative to the housing,
an actuator that moves the needle holder to a second retracted position relative to the housing, retracts the needle relative to the housing, simultaneously moving the cannula holder relative to the needle holder and relative to the housing to a second extended position, and extends the cannula relative to the needle.
2. An assembly as in claim 1 , wherein the needle holder is moveable along a first axis defined by the distal portion of the needle, the cannula holder being coupled to the needle holder and being moveable relative thereto between a first and a second position, the first position corresponding to the retracted position and the first extended position, the second position corresponding to the second extended position,
whereby the cannula holder is arranged substantially at the first position when the needle holder is moved from the first retracted position to the extended position.
3. An assembly as in claim 2 , wherein the cannula holder is moved from the first to the second position substantially simultaneously with the needle holder being moved from the extended to the second retracted position.
4. An assembly as in claim 2 , wherein the position of the distal cannula portion relative to the housing is substantially the same when the cannula holder is in its first and second extended positions.
5. An assembly as in claim 2 , wherein the position of the distal cannula portion relative to the housing is substantially the same during movement of the cannula holder between its first and second extended positions.
6. An assembly as in claim 5 , wherein the distal cannula portion is moved slightly back and forth relative to the housing during movement of the cannula holder between its first and second extended positions.
7. An assembly as in claim 2 , wherein the cannula holder is moveable along a second axis defined by the needle holder.
8. An assembly as in claim 7 , wherein the second axis is substantially perpendicular to the first axis.
9. An assembly as in claim 1 , comprising a first guide and a second guide, the cannula holder being adapted to engage the first guide as it is moved from its first retracted position to its first extended position, and adapted to engage the second guide as it is moved between its first and second extended positions.
10. An assembly as in claim 1 , comprising a third guide, the needle holder being adapted to engage the third guide as it is moved from its first retracted position to its first extended position, and from its first extended position to its second retracted position.
11. An assembly as in claim 9 , wherein the cannula holder and the needle holder are coupled to each other, and wherein the actuator means engages the cannula holder as it is moved between its first and second positions in engagement with the second guide, the coupling providing that the needle holder thereby is moved from its first extended position to its second retracted position.
12. An assembly as in claim 9 , wherein the actuator means comprises a spring, the spring being adapted to engage and move the needle holder from its first retracted position to its first extended position, and subsequently engage the cannula holder and move it between its first and second position in engagement with the guide, the needle holder thereby being moved from its first extended position to its second retracted position.
13. An assembly as in claim 1 , wherein the distal end of the cannula is arranged slightly proximally of the distal end of the needle as the needle and the cannula are being moved to their first extended positions relative to the housing.
14. An assembly as in claim 1 , wherein the cannula is moved relative to the needle along a non-linear path.
15. A medical device, comprising a mounting surface adapted for application towards a skin surface of a subject, and an assembly as defined in claims 1 .
16. A medical device as in claim 15 , wherein the distal portion of the needle and the cannula are arranged at an inclined angle relative to the mounting surface.