Skin Retention Device for a Medical Jet Injection Unit

Abstract

A skin retention device 10 for a medical jet-injection unit 20 comprises a contact face provided with adhesive 12 in the area surrounding and close to the injection opening(s) 11 of the nozzle 21 which ensures god contact between the nozzle 21 and the skin 30 of a subject in the area chosen for an injection. Consequently the injection force can be lowered dramatically. In case of two-stage jet-injections, the initial injection force can be lowered because the skin retention close to the injection point significantly reduces the energy consuming elastic expansion of the skin 30 in the injection area, and the second injection force can be lowered because of the high degree of fixed positioning of the injection opening of the nozzle 21 relative to the injection channel in the skin 30 made during the initial injection stage. Thus a high degree of injection safety is achieved, minimizing the risk of whet shots, while skin lift and lower injection force decreases the risk of damage of the underlying tissue.

1 . Skin retention device ( 10 ) for a medical jet-injection unit ( 20 ) comprising a contact face provided with adhesive ( 12 ) to be applied in contact with the skin ( 30 ) of a subject prior to an injection, said contact face further being provided with at least one injection opening ( 11 ),
 characterised in that the adhesive ( 12 ) substantially surrounds the injection opening(s) ( 11 ) in the proximity of the opening(s), such that skin retention against the contact face close to the injection opening(s) ( 11 ) is ensured, the energy required for the jet beam ( 25 ) to penetrate the skin ( 30 ) is limited and exact fixation of a jet beam ( 25 ) over the injection point throughout the injection period is ensured.   
   
   
       2 . Skin retention device ( 10 ) according to  claim 1 , characterised in that the adhesive ( 12 ) substantially surrounds the injection opening(s) ( 11 ) in a diameter ( 13 ) smaller than 3 mm, preferably smaller than 2 mm, preferably smaller than 1.1 mm, preferably smaller than 0.8 mm, preferably smaller than 0.6 mm. 
   
   
       3 . Skin retention device ( 10 ) according to  claim 1 , characterised in that all the contact face in the proximity of the injection opening(s) ( 11 ) is provided with adhesive ( 12 ). 
   
   
       4 . Skin retention device ( 10 ) according to  claim 1 , characterised in that all of the contact face is provided with adhesive ( 12 ). 
   
   
       5 . Skin retention device ( 10 ) according to  claim 1 , characterised in that the contact face has a convex shape. 
   
   
       6 . Skin retention device ( 10 ) according to  claim 1 , characterised in that the retention device ( 10 ) comprising a contact face is an integrated part of the jet-injection unit ( 20 ). 
   
   
       7 . Skin retention device ( 10 ) according to  claim 1 , characterised in that the jet-injection nozzle ( 21 ) and the contact face is manufactured in one piece, whereby the contact face is a part of the nozzle ( 21 ). 
   
   
       8 . Skin retention device ( 10 ) according to  claim 7 , characterised in that the jet-injection nozzle ( 21 ) and the contact face is manufactured of a moulded polymer material, or a blend of a polymer and an elastomer material. 
   
   
       9 . Skin retention device ( 10 ) according to  claim 1 , characterised in that the contact face is arranged circumferentially relative to the injection opening(s) ( 11 ), said retention device ( 10 ) having an initial configuration in which it is adapted to be placed against the skin ( 30 ) surface of the subject and being movable to a second configuration when the skin retention device ( 10 ) is pressed against the skin ( 30 ), thereby stretching the skin ( 30 ) in the area in contact with the contact face and pressing the injection opening(s) ( 11 ) against the skin. 
   
   
       10 . Skin retention device ( 10 ) according to  claim 1 , characterised in that the contact face has a cone shaped geometry providing an even stretch of the skin ( 30 ) radial outwards from the injection opening(s) ( 11 ) and providing lift of the skin ( 30 ) away from the subject without any force performed by the subject, once the skin retention device ( 10 ) has been applied in contact with the skin ( 30 ). 
   
   
       11 . Skin retention device ( 10 ) according to  claim 1 , characterised in that the adhesive ( 12 ) comprises different materials with different material characteristics. 
   
   
       12 . Skin retention device ( 10 ) according to  claim 11 , characterised in that the different adhesive materials are located on the contact face in geometrically limited zones, such that each material characteristics complement another. 
   
   
       13 . Skin retention device ( 10 ) according to  claim 1 , characterised in that the injection opening(s) ( 11 ) is covered and sealed with a sealing member. 
   
   
       14 . Skin retention device ( 10 ) according to  claim 13 , characterised in that the sealing member is a plug sealing the injection opening by pressure provided radial outwards towards the inner sides of the injection opening(s) or by pressure axially from the plug towards the injection opening(s). 
   
   
       15 . Skin retention device ( 10 ) according to  claim 14 , characterised in that the radial pressure on the plug is provided by a flexible or hard cover member fixed to the skin retention device ( 10 ). 
   
   
       16 . Method of operating a jet-injection unit ( 20 ), comprising the steps of
 (a) providing a jet-injection unit ( 20 ) comprising a nozzle ( 21 ), skin retention means ( 10 ) provided with adhesive ( 12 ) substantially surrounding the injection opening(s) ( 11 ) according to any of the preceding claims   (b) applying the skin retention device ( 10 ) to a skin ( 30 ) portion, thereby, adhering and fixating the skin ( 30 ) portion circumferentially relative to a desired skin ( 30 ) location for delivery of an amount of liquid   (c) releasing the application force performed via the retention device ( 10 ) to the skin ( 30 ) and in stead lifting the skin ( 30 ) in the vicinity of the injection point either by force applied by the user or provided by a flex effect of the retention device ( 10 ) or the lifting effect due to a convex shape of the skin retention device ( 10 ) and by means of the adhesive ( 12 )   (d) activating ( 24 ) the jet-injection unit ( 20 ) to generate an impulse for expelling an amount of liquid through the nozzle ( 21 ) and thereby through the skin ( 30 ) portion.   
   
   
       17 . Method according to  claim 16  further comprising
 (e) a two-stage injection where the first injection stage is a short high-pressure stage and the second injection stage is a low-pressure stage with a duration of more than 100 milliseconds, preferably more than 1 second, preferably more than 6 seconds.