Abstract:
The present application relates to an inserter device for inserting a medical device subcutaneous Iy which inserter device comprises a housing ( 1 ); a cover ( 2 ) which is slidably connected to the housing ( 1 ); a hub ( 5 ) for an insertion needle ( 4 ) which can be moved linearly relative to the housing ( 1 ) and relative to the cover ( 2 ); a primary spring ( 6 ) which moves the hub ( 5 ) for the insertion needle ( 4 ) relative to the cover ( 2 ) and which primary spring ( 6 ) is configured to pull the hub ( 5 ) for the insertion needle ( 4 ) either to a forward or to a retracted position wherein the inserter device further comprises means for biasing the primary spring ( 6 ) before insertion.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The invention concerns an insertion device for inserting a medical device or a part of medical device into the subcutaneous or intramuscular area of a patient. 
       BACKGROUND OF THE INVENTION 
       [0002]    An inserter device also called inserter or injector is commonly used in the medical field for inserting medical devices, such as infusion sets, sensors or the like, through the skin of a patient in a more or less automated fashion. 
         [0003]    Commonly, when using an inserter, the user, i.e. the patient or the treatment provider e.g. nurse, doctor, relative, or the like has to apply a force towards the surface of the skin of the patient in order to provide injection of the medical device or a part of the medical device having the form of a needle, a cannula, a sensor, or the like. This can cause physiological or psychological distress and/or discomfort, and may lead to inappropriate application of the medical device. Many people are afraid of sharp objects, such as injection needles and other penetrating devices, commonly used for medical treatment and therapy. This fear is often irrational, and it may hamper an appropriate medical treatment. For example in the case of self-medication, a lack of administration of an appropriate dose of a required medical composition can lead to complications, which may even be life-threatening. When treating diabetes, e.g. in juveniles, there is a risk that the required insulin-dose may not be self-administered due to irrational fear of the insertion needle, combined with a general lack of knowledge and awareness concerning the consequences of omitting the correct application of the device and dosage. 
         [0004]    WO 2008/065646 (Medingo Ltd) discloses an inserter for inserting a fluid delivery device subcutaneously in order to deliver a therapeutic fluid to a patient. The inserter configuration includes automatic insertion and retraction capabilities where a trigger button ( 330 ) actuates a set of springs which fire a penetrating cartridge ( 150 ) downward into the body of the patient and retract the penetrating member after insertion. Further, the inserter includes safety mechanisms for preventing misplacement and inadvertent misfiring. According to the present application it is not necessary to provide an inserter device with complex means preventing misfiring as the spring causing insertion is not biased or loaded before insertion is intended. Actually, the user bias or loads the insertion spring just before insertion takes place. 
         [0005]    A further known issue with insertion of medical devices is the risk of contamination of the penetrating member before or during application. This can easily lead to the introduction of an infection to a patient, e.g. through a contaminated insertion needle. The longer such a needle is exposed, the higher the risk of accidental contamination, e.g. by touching the needle with a finger, bringing the needle in contact with an unclean surface, or by airborne contamination, aerosol contamination and the like. Depending on the nature of the contamination (e.g. comprising virus, bacteria, fungus, yeast and/or prion) combined with the general health status of the patient, the resulting infection can rapidly turn into a life threatening situation. 
         [0006]    Finally, it is well known that contact with an infected, used needle especially in hospital environments can be life-threatening, and the risk of accidental exposure to contaminated material in the form of a used insertion needle must be minimized. 
         [0007]    Thus, there is an obvious need in the art for a robust, reliable, accurate, safe, hygienic, and user friendly insertion device, which addresses the issues discussed above. 
       SUMMARY OF THE INVENTION 
       [0008]    The present application relates to an inserter device for inserting a medical device subcutaneously which inserter device comprises
       a housing ( 1 );   a cover ( 2 ) which is slidably connected to the housing ( 1 );   a hub ( 5 ) for an insertion needle ( 4 ) which can be moved linearly relative to the housing ( 1 ) and relative to the cover ( 2 );   a primary spring ( 6 ) which moves the hub ( 5 ) for the insertion needle ( 4 ) relative to the cover ( 2 ) and which primary spring ( 6 ) is configured to pull the hub ( 5 ) for the insertion needle ( 4 ) either to a forward or to a retracted position wherein the inserter device further comprises means to be activated by the user for biasing the primary spring ( 6 ) before use i.e. before insertion.       
 
         [0013]    The insertion device of claim  1  is provided with means for biasing the primary spring which primary spring might either provide insertion or retraction of the insertion needle. That the spring is only biased upon use makes it possible to e.g. use plastic springs as these springs have a limited shelf life when they are biased. Also, it is not necessary to provide the insertion device of claim  1  with any means preventing misfiring as misfiring cannot take place before the spring has been biased or loaded. The cover actually covers the insertion needle both along the sides of the insertion needle which prevents the patient from observing the insertion needle before and after insertion, also the cover covers the end of the needle in such a way that the cover is provided with an opening at the end surface which is placed against the patients skin through which opening the insertion needle might pass through but the opening is too narrow to let a finger pass through the opening. 
         [0014]    According to one embodiment the inserter device comprises a secondary spring ( 7 ). A secondary spring can e.g. provide moving the needle hub ( 5 ) to a retracted position where the patient cannot get in contact with the insertion needle. 
         [0015]    According to one embodiment the means for biasing the primary spring comprises
       means for locking a first part of the primary spring ( 6 ) to a retracted position inside the cover ( 2 ), and   means for attaching a second part of the primary spring ( 6 ) to a displaceable part which displaceable part can move towards the penetration position of the insertion needle relative to the housing ( 1 ) and which displaceable part is either the needle hub ( 5 ) or a part connected to the needle hub ( 5 ) in such a way that the needle hub ( 5 ) travels with this part during biasing or loading of the primary spring ( 6 ).       
 
         [0018]    According to the embodiment of  FIG. 1-3  all parts of the primary spring  6  is locked to a retracted position inside the cover before biasing the spring i.e. during pre-use storage, see  FIG. 2A . When biasing the primary spring  6  a first part of the spring  6  stays at the retracted position relative to both the cover and the housing, this is shown in  FIG. 2B . In  FIG. 2B  the second part of the primary spring  6  is attached to the displaceable part being the spring loader  9 . According to the embodiment of  FIG. 4-7  all parts of the primary spring  6  is locked to a retracted position inside the cover before biasing the spring i.e. during pre-use storage, see  FIG. 5A . When biasing the spring  6  a first part of the spring stays at the retracted position while a second part of the spring which is connected directly to the needle hub  5  is moved towards the insertion point. The needle hub  5  is attached to the needle base plate  28  which does not move relative to the housing  1 . According to the embodiment of  FIG. 8-9  all parts of the primary spring  6  is locked to a retracted position inside the cover  2  before biasing the spring. When biasing the primary spring a first part of the spring stays in the retracted position relative to the cover as shown in  FIG. 9 , and a second part of the primary spring  6  is attached to the needle hub  5  which during biasing is displaced relative to the housing  1 . 
         [0019]    According to one embodiment the means for biasing the primary spring comprises
       a first set of contact surfaces between the cover ( 2 ) and the housing ( 1 ) and   a second set of contact surfaces (c 1 , c 2 ) between the housing and the needle hub ( 5 ),
 
when forcing the first set contact surfaces between the housing and the cover ( 2 ) in one direction, the needle hub ( 5 ) is forced from a retracted position relative to the housing to a forward position relative to the housing ( 1 ) as a result of the contact between the second set of contact surfaces and this change of position of the needle hub ( 5 ) relative to the housing ( 1 ) biases or loads the primary spring ( 6 ).
       
 
         [0022]    According to the first embodiment the first set of contact surfaces is provided between the outer surfaces of side walls the cover  2  and the inner surfaces of the side walls of the housing  1  which surfaces are designed such that inner surfaces of the housing  1  can rotate relative to the cover  2  while at least part of the surfaces slide against each other. The second set of contact surfaces is provided between a surface of the internal wings  10  of the housing  1  and the trigger plate  9 . 
         [0023]    According to the second embodiment the first set of contact surfaces is provided between the outer surfaces of side walls the cover  2  and the inner surfaces of the side walls of the housing  1  which surfaces are designed such that inner surfaces of the housing  1  can move in a direction along a longitudinally axe relative to the cover  2  while at least part of the contact surfaces have sliding contact. The second set of contact surfaces is provided between a surface of the needle base plate  28  which is stationary relative to the housing  1  and the needle hub  5 . 
         [0024]    According to one embodiment the first set of contact surfaces comprise an inner surface of the side walls of the housing ( 1 ) and an outer surface of the side walls of the cover, the two surfaces can either be rotated relative to each other or displaced along a longitudinal axis of the cover. 
         [0025]    According to one embodiment the second set of contact surfaces (c 1 , c 2 ) between the housing and the needle hub ( 5 ) comprises one or more contact surfaces (c 1 ) of the housing ( 1 ) which directly or indirectly are in contact with the needle hub ( 5 ) and a corresponding surface (c 2 ) of the needle hub ( 5 ) or a part connecting the needle hub ( 5 ). 
         [0026]    According to one embodiment the primary spring ( 6 ) at a second position is indirectly connected to the needle hub ( 5 ) in such a way that the primary spring ( 6 ) can be displaced by rotating the housing ( 1 ) relative to the cover ( 2 ). 
         [0027]    According to one embodiment the primary spring ( 6 ) comprises at least one elastically mounted arm ( 19 ) which arm ( 19 ) at the upper end is provided with an outward hook ( 20 ) securing the arm ( 19 ) to the cover ( 2 ) by catching around and upper edge of the cover ( 2 ). 
         [0028]    According to one embodiment an inclined surface ( 11 ) of the housing through contact with a surface of the primary spring ( 6 ) or of a part ( 9 ) in a fixed connection with the primary spring ( 6 ) forces the second end of the primary spring ( 6 ) away from upper end of the cover ( 2 ). 
         [0029]    According to one embodiment the primary spring ( 6 ) at a second position is indirectly connected to the housing ( 1 ) in such a way that the second position of the primary spring ( 6 ) can be displaced by pressing the housing ( 1 ) and the cover ( 2 ) towards each other along a longitudinal axis of the two parts. According to this embodiment the housing  1  is displaced telescopically relative to the cover  2 . This means that the device is relatively small during storage and only prolonged at the time of use where the user pulls the housing  1  away from the cover without separating the two parts. After insertion and retraction of the insertion needle the inserter device returns to the short form. 
         [0030]    According to one embodiment the primary spring ( 6 ) at the upper end is provided with an outward hook ( 20 ) securing the upper end of the primary ( 6 ) to the cover ( 2 ) by catching around and upper edge of the cover ( 2 ). 
         [0031]    According to one embodiment a central part of the housing through contact with a surface of the second end of the primary spring ( 6 ) or of a part ( 9 ) in a fixed connection with the second end of the primary spring ( 6 ) forces the second end of the primary spring ( 6 ) away from upper end of the cover ( 2 ). 
         [0032]    According to one embodiment the housing ( 1 ) comprises at least one protruding part ( 30 ) which upon contact with the upper end of the primary spring ( 6 ) connects unreleasably to the upper end of the primary spring ( 6 ). 
         [0033]    According to one embodiment the primary spring ( 6 ) is constituted by an elastic ring-shaped band. 
         [0034]    According to one embodiment a part of the housing ( 1 ) is in contact with the needle hub ( 5 ) and this part can move relative to the cover in a direction along the longitudinal axis of the cover ( 2 ) thereby moving the needle hub ( 5 ) relative to the cover ( 2 ) and pushing the needle hub ( 5 ) towards the skin of the patient and e.g. the part of the housing ( 1 ) in contact with the needle hub ( 5 ) is constituted by two flexible arms ( 40 ) provided with hooks which hooks are in contact with an upper surface of the needle hub ( 5 ). 
         [0035]    Another object of the invention is to provide medical device comprising a site ( 1 ) and a connector part ( 2 ) where the site ( 1 ) is stationary during use and attached to a patients skin and the connector part ( 2 ) can be attached to the site ( 1 ) during use which site ( 1 ) comprises
       a surface material ( 3 ) to be attached to the patients skin;   an inlet for fluid and a fluid path leading the fluid to a subcutaneous position;   positioning means ( 5 ) for the connector part ( 2 ) configured to provide a stationary i.e. fixed positioning of the connector part ( 2 ) relative to the site ( 1 ) in a horizontal direction during use; and
 
which connector part ( 2 ) comprises
   an outlet for fluid ( 18 ) which during use protrudes through the inlet for fluid of the site ( 1 );   means for positioning ( 7 ) corresponding to the positioning means ( 5 ) on the site ( 1 ) wherein the medical device is a two piece device in the use-situation and the site ( 1 ) is provided with positioning means ( 5 ) defining more than one possible position for the connector part ( 2 ) during use.       
 
         [0041]    According to one embodiment the connector part ( 2 ) is releasably attached to the site ( 1 ) and the site ( 1 ) comprises attachment means ( 4 ) for the connector part ( 2 ) providing releasable attachment of the connector part ( 2 ) to the site ( 1 ) during use; and the connector part ( 2 ) comprises corresponding means for attachment ( 6 ) configured to interact with the attachment means ( 4 ) on the site ( 1 ). 
         [0042]    According to one embodiment the positioning means ( 5 ) of the site ( 1 ) comprise at least two openings ( 5 ) where at least one opening ( 5 ) correspond(s) to a protruding part ( 7 ) on the connector part ( 2 ) when the connector part ( 2 ) is placed in a use position. The positioning means ( 5 ) of the site ( 1 ) can comprise at least two openings ( 5 ) where two or more openings ( 5 ) correspond to two or more protruding part ( 7 ) on the connector part ( 2 ) when the connector part ( 2 ) is placed in a use position. 
         [0043]    According to one embodiment the positioning means ( 5 ) of the site ( 1 ) comprise 2 to 10 openings ( 5 ) corresponding to 2 to 10 protruding parts ( 7 ) on the connector part ( 2 ) when the connector part ( 2 ) is placed in a use position. 
         [0044]    According to one embodiment the surface material ( 3 ) to be attached to the patient&#39;s skin is adhesive on at least one surface. 
         [0045]    According to one embodiment the site ( 1 ) has a subcutaneous part when positioned on the patients skin or has means for attaching a subcutaneous part after positioning the site on the patients skin. The subcutaneous part can be a soft or hard cannula or a sensor or a combination of a cannula and a sensor. 
         [0046]    According to one embodiment the attachment means ( 4 ) of the site ( 1 ) comprises an increase or a decrease in a cross-sectional dimension providing an inward or outward step in a vertical profile. The attachment means can be provided as an outward rim at an outer vertical surface or an inward rim at an inner vertical surface. 
         [0047]    According to one embodiment the means for attachment ( 6 ) of the connector part ( 2 ) comprises actuation means ( 15 ) in the form of at least one arm placed along the outer edge of the connector part ( 2 ) which arm is fastened to the connector part ( 2 ) at one end and can be pivoted around this fastening point, the arm is provided with retaining means ( 14 ) configured to prevent vertical movements of the connector part ( 2 ) relative to the site ( 1 ). 
         [0048]    According to one embodiment the means for attachment ( 6 ) of the connector part ( 2 ) comprises actuation means ( 15 ) in the form of two oppositely positioned arms which arms each are pivotally attached at one end and each arm is provided with retaining means ( 14 ) and the distance between the retaining means on each arm can be varied due to the pivotal movement of the two arms. 
         [0049]    According to one embodiment the connector part ( 2 ) comprises means for transferring liquid from the connector part ( 2 ) to the patient. 
         [0050]    According to one embodiment the connector part ( 2 ) comprises a connector needle in the form of a tubular element ( 18 ) to be inserted through a septum of the site ( 1 ). The connector part ( 2 ) can be provided with guiding means ( 17 ) adapted to guide the tubular element ( 18 ) through a penetrable part of the site ( 1 ) in a vertical direction. 
         [0051]    According to one embodiment the site ( 1 ) during use comprises a septum facing upwards i.e. having an open surface in a vertical direction. Normally the septum has the form of a flat or disc-shaped portion having same cross-section as the cavity surrounding it. 
         [0052]    According to one embodiment the device comprises a leakage indication system comprising leakage indication means adapted to provide a colour change upon leakage of a fluid, the indication means being provided on a surface of the site ( 1 ) near the insertion site, and being visible i.e. inspectable upon use. The leakage indication means can be insulin detection means. 
         [0053]    According to one embodiment the leakage indication system comprises a reference marker indicating the visual change to be expected upon leakage. The visible change could e.g. be a change of colour of the indicator means. 
         [0054]    According to one embodiment the device comprises a subcutaneous part comprising a coloured or contrast-enhanced cannula, and the site ( 1 ) comprises a transparent area arranged near the insertion site, said transparent area being adapted to allow visible detection of misplacement of the cannula during use. 
       DEFINITIONS 
       [0055]    “Proximal” means defines a part of or a side of a unit which compared to a similar opposite part or side of the same unit is closest to the patient&#39;s skin when the unit is in use. 
         [0056]    “Distal” defines the part or side of a unit which is opposite the proximal part or side of the same unit. 
         [0057]    When there is referred to that something is “vertical” then there is referred to a line or direction which would be perpendicular to the patient&#39;s skin when the device is in use. 
         [0058]    When there is referred to that something is “horizontal” then there is referred to a line or direction which would be parallel to the patient&#39;s skin when the device is in use. Also, a rotation movement in a plane level parallel to the patient&#39;s skin is considered to be a “horizontal movement”. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0059]    A detailed description of embodiments of the current invention will be made with reference to the accompanying figures, wherein like numerals designate corresponding parts in different figures. 
           [0060]      FIG. 1  shows an exploded view of a first embodiment of an inserter device according to the invention, this inserter has automatic insertion and automatic retraction of the insertion needle. 
           [0061]      FIGS. 2A-B  show the first embodiment of the inserter device respectively in a ship state and in a loaded state. 
           [0062]      FIG. 3A-C  shows the first embodiment of the inserter device respectively in a state where the insertion needle is fully inserted and in a state where the insertion needle has been retracted to a fully retracted position, and details of the release of the needle hub from the trigger plate. 
           [0063]      FIG. 4  shows an exploded view of a second embodiment of an inserter device according to the invention, this inserter has manual insertion and automatic retraction of the insertion needle. 
           [0064]      FIGS. 5A-B  show the second embodiment of the inserter device in two states; first in a state before insertion and second in a state where the insertion needle is fully inserted. 
           [0065]      FIG. 6  shows details of the second embodiment of the inserter device. 
           [0066]      FIG. 7  shows the second embodiment of the inserter device in a state where the insertion needle is fully retracted and the cover is distanced as much as possible from the housing. 
           [0067]      FIG. 8A-D  show a third embodiment of an inserter device according to the invention. The third embodiment is shown in four states: A: ship state; B: just before loading; C: insertion needle fully inserted; D: insertion needle fully retracted. 
           [0068]      FIG. 9  show the position of the rubber band used with the third embodiment of the inserter device. 
           [0069]      FIG. 10  shows the first embodiment of the inserter device in a ship state. 
           [0070]      FIG. 11  shows a lid and a corresponding cover according to the first embodiment of the inserter device. 
           [0071]      FIG. 12  shows an enlargement of a needle hub used with the first and the second embodiment. 
           [0072]      FIGS. 13A  and B shows an embodiment of the housing and  FIG. 13C  shows an embodiment of the cover. 
           [0073]      FIGS. 14A-C  show a site of a first embodiment of a medical device: A: a site seen from above; B: a site and a cannula part seen from the side; C: the cannula part seen from the side. 
           [0074]      FIGS. 15A-D  show a site and a connector part according to a first embodiment of the medical device: A: the connector part and the site provided with a cannula part in position just before assembling; B: the connector part and the site shown in A in assembled position; C: connector part seen from below; D: Connector part seen from above. 
           [0075]      FIG. 16A-D  show a second and a third embodiment of a site of a medical device according to the invention: A: a second embodiment of a site seen from above and from a side view; B: the site of A and a cannula part seen from the side; C: the cannula part seen from the side; D: a third embodiment of a site seen from the side. 
           [0076]      FIG. 17  shows show the site and a connector part according to a second or third embodiment of the medical device: A: the connector part and the site provided with a cannula part in position just before assembling; B: the connector part and the site shown in A in assembled position; C: connector part seen from below; D: Connector part seen from above. 
           [0077]      FIG. 18  shows a leakage indication system. Left: top view; right: bottom view. A: example of a “complete crawl out” where a portion of the catheter or cannula becomes visible through a transparent plaster. B: example of a “partial crawl out” or “buckling/crimping” of the catheter or cannula, where the catheter or cannula is not visible through the transparent plaster. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0078]      FIG. 1  shows a first embodiment of an inserter device. The embodiment has automatic insertion and automatic retraction of the insertion needle and comprises a housing  1 , a cover  2 , an insertion needle  4  attached to a needle hub  5 , a primary spring  6  used for subcutaneous insertion of the insertion needle  4 , a secondary spring  7  used for retraction of the insertion needle  4 , a trigger plate  8  and a spring loader  9  i.e. this embodiment comprises 7 separate pieces,  8  including a lid  12  (see  FIGS. 2A and 11 ), and all of the pieces are normally made of moulded plastic except e.g. the insertion needle  4  which might be made of metal. 
         [0079]    The housing  1  is provided with one or more internal wings  10  having a rounded profile and an inclined surface facing the direction of rotation of the housing  1 . That the profile is rounded means that the length of the internal wing  10  follows the direction of rotation when the housing  1  is rotated around the longitudinal central axis of the housing  1 . The first embodiment is provided with three of these internal wings  10  which wings  10  are attached to or moulded as part of the internal top surface of the housing  1 . 
         [0080]    Also the outer wall of the housing  1  is provided with inclined contact surfaces  11  facing the direction of rotation of the housing at the time where the housing  1  is released from the lid  12 . The lid  12  provides a complete cover of the internal parts of the inserter device during shipment and thereby makes it possible to keep the internal parts sterile before use. According to the first embodiment three inclined contact surfaces  11  form part of the outer wall of the housing  1  defining three contact surfaces. The lid  12  is also provided with inclined contact surfaces  13  (see  FIGS. 2A and 11 ) facing the direction of rotation of the lid  12  at the time where the housing  1  is released from the lid  12 . 
         [0081]    The inserter device is loaded as the lid  12  is removed by rotating the lid  12  relative to the housing  1 . The inclined contact surfaces  11  and  13  respectively of the housing  1  and of the lid  12 , slide against each other as the lid  12  is rotated/removed whereby the lid  12  and the housing  1  are forced in opposite directions along the longitudinal axis of the inserter device (illustrated in  FIG. 10 ). 
         [0082]    The cover  2  is locked longitudinally to the housing  1  by longitudinal locking means i.e. the cover  2  cannot move unrestricted in a longitudinal direction relative to the housing  1 . According to the first embodiment of the inserter device the longitudinal locking means comprise a protruding edge  35  provided on the top half of the cover  2  extending perpendicularly to the longitudinal axis of the inserter device on the outer surface of the cover  2 , and a corresponding groove  26  extending on the inner surface of the housing  1 , these corresponding features locks the cover  2  to the housing  1  although the cover  2  is allowed to move relative to the housing  1 . 
         [0083]    The cover  2  is also locked rotationally relative to the lid  12  and therefore the cover  2  will rotate together with the lid  12 . According to the present embodiment the cover  2  is rotationally locked to the lid  12  by rotational locking means comprising three longitudinal grooves  17  (“longitudinal” means that the grooves  17  are parallel to the longitudinal central axis of the inserter device) provided on the outer surface of the cover  2  which grooves  17  each correspond to a longitudinal protruding part  18  (see  FIGS. 2A and 11 ) on the lid  12 . The rotation of the lid  12  causes the inclined surface of each internal wing  10  of the housing  1  to be pushed against a surface of the spring loader  9 , according to the first embodiment the spring loader  9  is provided with a number of wing openings  14  corresponding to the number of internal wings  10  of the housing  1  and each internal wing  10  of the housing pushes against an inner surface of such an opening  14 . As the contact surface of each internal wing  10  is inclined and as the spring loader  9  is kept in position by the elastic pressure of the secondary spring  7 , the pressure against the inner surface of the opening  14  forces the spring loader  9  away from the top of the housing  1 . 
         [0084]    Both the spring loader  9  and the trigger plate  8  are locked rotationally relative to the cover  2  by rotational locking means, i.e. both parts rotate together with the cover  2 . According to the first embodiment of the inserter device the locking means comprises three peripheral protruding parts  15  of respectively the spring loader  9  and the trigger plate  8  fitting into three corresponding longitudinal tracks  16  on the inner surface of the cover  2 . 
         [0085]    The trigger plate  8  is attached to the housing  1  close to the top of the housing  1  by to flexible arms  19  provided with hooks  20 . The two oppositely positioned flexible arms  19  keep the trigger plate  8  in a position close to the housing top as the hooks  20  catch around an upper surface of the housing  1 . According to the first embodiment of the inserter device this upper surface is provided by two recesses in the upper edge of the housing where the positions of the recesses correspond to the position of the hooks  20 . When the two oppositely positioned flexible arms  19  are pushed out of the recess the trigger plate is forced forward by the primary spring  6  if the inserter device is in a loaded state. 
         [0086]    The trigger plate  8  also has a central opening  21  through which the insertion needle  4  of the needle hub  5  extends. The central opening  21  is though too small for the needle hub  5  to pass through so the needle hub  5  is retained by the trigger plate  8 . 
         [0087]    The primary spring  6  is placed between the trigger plate  8  and the bottom of the cover  2  where the bottom is considered to be the end of the cover to which the insertion needle  4  points and where the infusion site is positioned at the position  3  when the infusion site is separated from the subcutaneous part. The primary spring  6  is at one end unreleasably attached to the trigger plate  8  and at another end the primary spring  6  is attached to protruding legs  24  of the spring loader  9 . During the rotation of the housing  1  relative to the lid  12 , the inserter device is loaded by extending the primary spring  6  by forcing the spring loader  9  forward. One end of the primary spring  6  is attached to the protruding legs  24  of the spring loader  9  while the second end of the primary spring  6  is attached to the stationary trigger plate  8 . The trigger plate  8  is stationary relative to the housing  1  during loading of the springs. Actually, two ends of the primary spring  6  is fastened to the protruding legs  24  of the spring loader  9  according to the first embodiment as this embodiment of the primary spring  6  comprises two half circles of moulded plastic where one end of each half circle has to be displaced in order to load the primary spring  6 . As the primary spring  6  is forced into a loaded state by being extended, it will attempt to return to the unloaded state by contracting. 
         [0088]    The secondary spring  7  is forced into a loaded state when it is compressed and it will attempt to return to an unloaded state by extending. The secondary spring  7  is placed between the spring loader  9  and the trigger plate  8 , and the secondary spring  7  is loaded when the lid  12  is rotated relative to the housing  1  and then removed whereby the spring loader  9  is pressed against the trigger plate  8 . Finally the lid  12  is removed from the housing  1  by this rotating action as the lid  12  and the housing  1  are pushed in opposite directions along the longitudinal axis of the inserter device during the rotation. According to the first embodiment the secondary spring  7  is a spiral spring made of plastic. 
         [0089]    The needle hub  5  is before loading and until the springs  6  and  7  reach the fully loaded state attached to the spring loader  9 . The spring loader  9  has a central opening  22  into which opening  22  the top of the needle hub  5  fits from the lower side i.e. the side which is facing the infusion site. The opening  22  is too small for the needle hub  5  to pass through, and as the secondary spring  7  pushes upward on the needle hub  5  i.e. toward the spring loader  9 , the secondary spring  7  keeps the needle hub  5  in the correct position relative to the spring loader  9 . 
         [0090]    The needle hub  5  is provided with locking means  23  locking the needle hub  5  to the trigger plate  8  in the longitudinal direction when the needle hub  5  is pushed sufficiently through the central opening  21 . According to the first embodiment of the inserter device the locking means  23  have the form of two oppositely positioned flexible arms each provided with an outward hook at the end, the outer surface of each hook having an inclined or rounded surface (see  FIG. 12 ). 
         [0091]    The cover  2  comprises release means  27  for releasing the needle hub  5  from the trigger plate  8  after full insertion of the insertion needle  4 . The release means  27  comprises two upright parts which extend from the lowest surface of the cover  2 , the two upright parts correspond to the locking means  23  of the needle hub  5  and when the locking means  23  of the needle hub  5  are pressed against the release means  27  the needle hub  5  is released from the trigger plate  8 , and the needle hub  5  can be pushed to a retracted position by the secondary spring  7 . 
         [0092]    The first embodiment of the inserter device according to the invention functions as illustrated in the  FIGS. 2 and 3 . 
         [0093]      FIG. 2A  shows the inserter device in the ship state i.e. the state which the device is in during storage i.e. before use. The primary spring  6  is in a completely unloaded state and the secondary spring  7  is in an almost unloaded state. Normally, it is advantageous that the springs are in an unloaded or almost unloaded state during storage as this will keep the springs from deteriorating functionally during storage. The spring loader  9  rests against the top wall of the housing  1  and is prevented from changing position by the secondary spring  7 . The lid  12  is mounted onto the cover  2  resting against the inclined contact surfaces  11  of the housing  1 . The hooks  20  of the flexible arms  19  of the trigger plate  8  rest in the recesses along the upper edge of the housing and keep the trigger plate in the correct pre-trigger position. An infusion site is positioned at the position  3  for the infusion site and a subcutaneous part is loaded onto the insertion needle  4  of the needle hub  5 . All parts inside the closed room formed by the housing  1  and the lid  12  have been sterilised after manufacture and assembling of the inserter device. 
         [0094]    When a user wants to use the inserter device, the user will first remove the lid  12  by rotating the lid  12  relative to the housing  1 . This action not only removes the lid  12  from the device but also loads the inserter device simultaneously. Normally the two parts, housing  1  and lid  12 , will be manufactured in bright and easily distinguishable colours which will make it easy for the user to identify the direction of rotation for each part due to the inclined corresponding surfaces (see  FIG. 10 ). 
         [0095]      FIG. 2B  shows the inserter device in a loaded state. Both the primary spring  6  and the secondary spring  7  are in a fully loaded state. The spring loader  9  is now positioned at the outermost end of the internal wings  10 . The lid  12  has been removed. The hooks  20  of the flexible arms  19  of the trigger plate  8  still rest in the recesses along the upper edge of the housing and keep the trigger plate in the correct pre-actuated position. The locking means  23  of the needle hub have been locked to the trigger plate  8  i.e. the trigger plate  8  and the needle hub  5  will now move together. The infusion site is still positioned at the position  3  for the infusion site and a subcutaneous part is still loaded onto the insertion needle  4  of the needle hub  5 . Non-sterilised air has to some degree access to the inner room formed by the cover  2  and the housing  1  and the user will therefore have to use the inserter device within a short time period. 
         [0096]    When the user has prepared the inserter device for insertion by removing the lid  12 , the user places the device against the skin of the patient whether this might be the user himself or a second person. According to the shown embodiment the infusion site is separated from the subcutaneously positioned part and placed in the position  3 . Normally an adhesive surface of the infusion site is exposed which adhesive surface is used to attach the infusion site releasably to the patients skin. The adhesive surface could be exposed automatically upon removal of the lid  12  or it could be exposed manually e.g. by removing a release paper from the adhesive surface before use. When the adhesive surface is exposed the end of the inserter device comprising the infusion site is pushed against the skin of the patient, and then the trigger is activated. The trigger according to the shown embodiment is activated by pressing two opposite flexible points at the top end of the housing  1 . This pressure releases the two flexible arms  19  of the trigger plate  8  and the trigger plate  8  is then no longer held in the stationary position at the top of the housing  1  as the primary spring  6  is attached unreleasably to the trigger plate  8  and will force the trigger plate  8  to a new stationary position at the bottom of the cover  2 . 
         [0097]      FIG. 3A  shows the inserter device in an unstable state where the insertion needle  4  is inserted subcutaneously. The primary spring  6  is unloaded and the secondary spring  7  is in a fully loaded state. The spring loader  9  is still positioned at the outermost end of the internal wings  10 . The hooks  20  of the flexible arms  19  of the trigger plate  8  are released from the upper edge of the housing and the trigger plate  8  is moved to the end position at the bottom of the cover  2 . The subcutaneously part has been inserted subcutaneously and is now unreleasably attached to the infusion site; the infusion site is still positioned at the position  3 . The locking means  23  of the needle hub  5  have just gotten into contact with the release means  27  of the housing  1 , and the needle hub  5  is no longer attached to the trigger plate  8 . 
         [0098]      FIG. 3B  shows the inserter device in the final state where the needle hub  5  has been retracted from the infusion site. Both the primary and the secondary springs  6  and  7  are unloaded. The secondary spring  7  has pushed the needle hub  5  to the retracted position as soon as the needle hub  5  has been released from the trigger plate  8 . The secondary spring  7  is placed between the needle hub  5  and the trigger plate  8  thereby providing a force pushing these two parts away form each other. 
         [0099]      FIG. 3C  shows in detail how the release of the needle hub  5  from the trigger plate is performed. An edge of the stationary release means  27  forces the arms provided with outward hooks of the needle hub  5  inwards, and this action causes the needle hub  5  to be released from the trigger plate  8 . 
         [0100]      FIG. 4  shows a second embodiment of an inserter device. Parts similar to parts of the first embodiment are illustrated with the same reference numbers as used when describing the first embodiment e.g. the needle hub  5 , the primary spring  6 , the secondary spring  7  and the release means  27  for the needle hub  5  are identical to the corresponding parts of the first embodiment. The second embodiment has manual insertion and automatic retraction of the insertion needle and comprises a housing  1 , a cover  2 , an insertion needle  4  attached to a needle hub  5 , a primary spring  6  used for retraction of the insertion needle  4 , a secondary spring  7  used to provide a comfortable resistance when manually inserting the insertion needle, a needle base plate  28  and a not shown lid i.e. this embodiment comprises 7 separate pieces and all of the pieces are normally made of moulded plastic except e.g. the insertion needle  4  which might be made of metal. 
         [0101]    As the first embodiment of the inserter device, the internal parts of the device are held in a sterile environment as long as the not shown lid is attached to the housing  1  and encloses the cover  2 . 
         [0102]    The housing  1  comprises two extending parts  29  extending from the closed top surface of the housing  1 . The two extending parts  29  are slightly flexible i.e. they can pivot relative to the position where they are fixed, this flexibility is only used during manufacturing of the device. The housing  1  also comprises two pairs of catchers  30  which catchers  30  are formed as oppositely facing hooks and each pair of catchers  30  can catch and hold on to hole  31  at one end of the primary spring  6 . Also the housing  1  comprises a series of elevations  32  close to the lower edge, the elevations  32  might be elongated and in a direction perpendicular to the longitudinal axis of the device or they might be formed as points. The elevations  32  prevent the cover  2  from sliding out of the housing  1  i.e. the cover can move longitudinally relative to the housing  1  but only to a certain degree as the elevations  32  meet restriction e.g. in form of protrusions  35  on the outer surface of the cover  2 . 
         [0103]    The cover  2  comprises a position  3  for an infusion site at the bottom of the cover  2  and release means  27  positioned on top of the position for the infusion site of the same form as the release means  27  of the first embodiment. Further the cover  2  comprises two upright walls  33  protruding opposite each other from the side surface of the cover  2 . The upright walls  33  extend from the top of the cover  2  to the bottom and correspond to peripheral openings  34  in the needle base plate  28  allowing the needle base plate  28  to slide in the longitudinal direction of the cover  2  along the upright walls  33 . The cover  2  also comprises the circular protrusion  35  extending from the outer surface of the cover  2  near the top end. 
         [0104]      FIG. 5A  shows the inserter device in the ship state i.e. an unloaded state which the device is in during storage i.e. before use. The primary spring  6  is unloaded and the secondary spring  7  is almost unloaded. That the secondary spring  7  is almost unloaded means that it exercises a slight pressure against the surfaces between which it is placed. The needle hub  5  extends through central openings in both the primary spring  6  and the needle base plate  28 . The needle hub  5  is inserted through the central openings during manufacturing of the device and as the top of the needle hub  5  is provided with an increased or increasing diameter, the needle hub  5  cannot pass through the central opening of the primary spring  6 . Also the needle hub  5  comprises locking means  23  of the same form as illustrated for the first embodiment and these locking means  23  catch around the lower surface of the needle base plate  28  and lock the primary spring  6  and the needle base plate  28  together. The primary spring  6  is at this state attached to the top of the cover  2  as two protruding parts at each their end of a flexible half circle spring are hooked around the top of an upright wall  33  of the cover  2 . The needle base plate  28  is locked to the end of the extending parts  29  of the housing  1 . The secondary spring  7  pushes the bottom of the cover  2  away from the needle base plate  28  and thereby upholds the length of the device. When a user wants to start using the inserter device, the not shown cylindrical lid is first removed. Any release liner covering the adhesive distal surface of the infusion site is released. Then the user places the device with the bottom of the cover  2  against the patient&#39;s skin and pushes the housing toward the skin of the patient. 
         [0105]      FIG. 5B  shows the inserter device in a loaded state—just before release of the needle hub  5 —where user has pushed the housing  1  toward the patients skin, and the insertion needle  4  has been fully inserted. The primary spring  6  has been extended and thereby loaded. As the central part of the primary spring  6  is locked between the needle hub  5  and the needle base plate  28 , the primary spring  6  is forced into the extended state as the housing  1  and thereby the extending parts  29  are pushed down. The secondary spring  7  is loaded and the user has to overcome the resistance provided by the secondary spring  7  during loading. When the housing  1  is in the position of this state the catchers  30  extending from the top surface of the housing  1  will have pivoted away from each other i.e. outwards as the protruding parts of the primary spring  6  comprising the holes  31  are squeezed in between the two hooks of the catchers  30 . The action of the catchers  30  returning to the inward position causes a click-sound and indicates to the user that the insertion needle  4  has been fully inserted, and as the click sounds one end of the primary spring  6  is locked to the top surface of the housing  1  in stead of being hooked around the top of the upright walls  33  of the cover  2 . 
         [0106]    As the needle hub  5  is pressed against the release means  27 , the needle hub  5  is released from the needle base plate  28  as the arms of the locking means  23  are pushed inward i.e. toward each other, and the hooks of the locking means  23  release the grip of the needle base plate  28 . 
         [0107]    When one end of the primary spring  6  is attached to the catchers  30  of the top surface of the housing  1  and the other end is no longer locked to the needle base plate  28 , the primary spring  6  can return to the unloaded state by contracting, and this contraction causes the withdrawal of the needle hub  5  to a retracted position near the top of the housing  1 . 
         [0108]      FIG. 6  shows in detail in the left view how the needle hub  5  is released from the needle base plate  28  when the locking means  23  in the form of two oppositely flexible arms with outward hooks are pressed together as a result of the interaction with the release means  27  which are in the form of two upright protrusions of a hard material and the inclined outer surfaces of the two hooks. The release of the needle hub  5  takes place when the insertion needle  4  has been inserted to such a depth i.e. the housing  1  has been pushed forward to such a degree that the outward hooks of the flexible arms touches the release means  27 . Also another detail is shown in the right view, this view shows how the upper end of the primary spring  6  which is provided with a hole  31  hooks around the upright wall  33  of the cover  2 . At the position shown in  FIG. 6  the housing  1  and the cover  2  are pressed together to the outmost degree, i.e. the combination of the housing  1  and cover  2  is as short as possible. 
         [0109]      FIG. 7  shows the second embodiment of the inserter in an unloaded state obtained after insertion of the insertion needle. The primary spring  6  is in a completely unloaded state and the secondary spring  7  is in an almost unloaded state, the secondary spring  7  is providing a force big enough to keep the cover  2  and the housing  1  away from each other in such a degree that the assembled two parts i.e. housing  1  and cover  2 , will be as long as possible, and the length is determined by the elevations  32  of the housing  1  getting in contact with the circular protrusion  35  of the cover  2 . 
         [0110]      FIGS. 8 and 9  illustrate a third embodiment of an inserter according to the present invention. Parts similar to parts of the first and second embodiments are illustrated with the same reference numbers as used when describing the two former embodiments e.g. the needle hub  5 , the primary spring  6 , and the release means  27  for the needle hub  5  are similar to the corresponding parts of the first embodiment. The third embodiment has manual insertion and automatic retraction of the insertion needle. This embodiment comprises 5 separate pieces and all of the pieces are normally made of moulded plastic except the primary spring  6  which is e.g. made of soft flexible rubber band and e.g. the insertion needle  4  which might be made of metal. 
         [0111]    The  FIGS. 8A-8D  also shows a two part infusion device comprising a subcutaneous part  36  and an infusion site  37 . The subcutaneous part  36  comprises a part which is to be inserted subcutaneously in the patient and is preloaded onto the insertion needle  4  and the infusion site  37  is attached to the cover  2  inside the position  3  for infusion site. The inserter device might also be used for insertion of other medical devices comprising a subcutaneous part whether such a device would be in one or more pieces, and then the position  3  for the infusion site would have to be adapted to the medical device in question. 
         [0112]      FIG. 8A  shows the third embodiment of the inserter device in a ship state which is an unloaded state. As illustrated in  FIG. 9 , the primary spring  6  which according to this embodiment can be constituted by a single circular rubber band is attached to the top of the cover  2  and supports under the needle hub  5  i.e. the primary spring  6  pulls the needle hub  5  and the top of cover  2  together. The needle hub  5  of this embodiment is constructed with a circular top plate  38  having a diameter small enough to allow the needle hub  5  to slide up and down inside the cylindrical cover  2 . The circular top plate  38  has openings  39  allowing for the rubber band constituting the primary spring  6  to pass from the lower side of the needle hub  5  to the top of the cover  2  without by its presence disturbing the sliding movement of the needle hub  5  relative to the cover  2 . According to the shown embodiment the rubber band  6  is attached to the top of the cover  2  by winding it around a protruding part of the edge  42 , this is easily done as the rubber band is very flexible. The circular top plate  38  is also provided with two openings and a flexible loading arm  40  provided with an inward hook extend through each opening. The inserter device is in  FIG. 8A  provided with a lid  12  and the lid  12  assures sterile conditions for the internal parts of the inserter device before opening. 
         [0113]      FIG. 8B  shows the third embodiment of the inserter device in a pre-loaded state, the primary spring  6  (not shown) is unloaded in this state. The lid  12  has been released from the housing  1  and the housing  1  has been pulled back relative to the cover  2 . This action causes the inward hooks of the two flexible loading arms  40  to move to the upper side of the circular top plate  38  of the needle hub  5 , and due to the flexibility of the loading arms  40  the hooks are caught on top of the needle hub  5 . When the device has been put into this state the device is ready for insertion when the lid  12  has been removed from the device. Normally removal of the lid  12  will lead to that a protective layer such as a release layer is removed from the adhesive side of the medical device placed in the position  3  for the infusion site. 
         [0114]      FIG. 8C  shows the third embodiment of the inserter device in a fully loaded state where the insertion needle  4  is also fully inserted. The primary spring  6  is fully loaded in this state as the rubber band which is attached to the top of the cover  2  has been stretched to its maximum as the needle hub  5 , which the rubber band is placed under, is at its lowest position. In this position the release means  41  get in contact with the flexible loading arms  40  and push the loading arms  40  outward i.e. away from each other. This movement causes the needle hub  5  to be released from the hooks of the loading arms  40  which result in the needle hub  5  being pulled upwards to the top of the cover  2  where the opposite ends of the circular rubber band are fastened. 
         [0115]      FIG. 8D  shows the third embodiment of the inserter device in the final unloaded state where the needle hub  5  and thereby the insertion needle  4  has been brought into the retracted position. The state is similar to the unloaded state shown in  FIG. 8A  except that the two part infusion device  36 ,  37  is now assembled and the subcutaneous part  36  is inserted into the infusion site  37 . 
         [0116]      FIG. 9  show a possible position of a primary spring  6  in the form of an elastic such as a rubber band used with the third embodiment of the inserter device. The elastic band is attached to the top of the cover  2  by wrapping parts of the elastic band around protruding parts  42  extending outward from the upper edge of the cover  2 . The central plate being encompassed by the wall of the cover  2  is a circular top plate  38  of the needle hub  5  and the elastic band passes through openings  39  provided in the top of the needle hub  5  which openings are large enough to prevent the elastic band from interfering to interfere with the movement of the needle hub  5  relative to the cover  2 . 
         [0117]      FIG. 10  shows the first embodiment of the inserter device in a ship state. The housing  1  is dark (green) and the lid  12  is light (grey). The difference in colour provides the user with a clear impression of which direction to twist the two parts relatively. The two central arrows of the figure illustrates the direction of rotation of the housing  1  relative to the lid  12 , and the two arrows at each end of the device illustrate the direction of movement of respectively the housing  1  and the lid  12  upon rotation. The inclined surfaces  13  and  11  respectively of the lid  12  and the housing  1  provide a robust guidance for the rotation/separation of the two parts i.e. the user only has to focus on the rotation as the linear separation of the two parts is an unavoidable consequence of the rotation. The rotation also causes the device to be loaded which result in that the user only has to perform one act i.e. rotate the lid  12  relative to the housing  1  and then the device is in a ready-to-use state. 
         [0118]      FIG. 11  shows a lid and a corresponding cover according to the first embodiment of the inserter device. 
         [0119]      FIG. 12  shows an enlargement of a needle hub used with the first and the second embodiment of the inserter device. The needle hub  5  has two flexible arms comprising locking means  23  in the form of outward hooks. Also, the needle hub  5  comprises a top part which is used to attach the needle hub  5  to e.g. the trigger plate  8  of the first embodiment. 
         [0120]      FIGS. 13A  and B shows embodiments of a housing to be used with the first embodiment and  FIG. 13C  shows an embodiment of a cover to be used with the first embodiment. 
         [0121]      FIGS. 14A , B and C shows a first embodiment of a medical device according to the invention, the medical device is a device comprising a site  100  such as an infusion site which can be combined with a subcutaneous part  36  such as a cannula part. If the subcutaneous part is a cannula part  36 , it comprises a disc like septum  900  blocking the entrance to a cannula which cannula during use is positioned subcutaneously. The site  100  comprises three parts: a surface material  300  which during use is attached to the patients skin, a circular or ring-shaped part  101  attached unreleasably to the upper surface of the surface material  300  and a central part  111  which is also attached unreleasably to the upper surface of the surface material  300  and which part is adapted to hold the subcutaneous part  36 . The surface material  300  is normally made of a patch of weaved or non-weaved material and is adapted to be releasably attached to the patient&#39;s skin during use, e.g. by an adhesive surface facing the skin. The site  100  comprises positioning means  500  corresponding to positioning means  700  on a connector part, such a connector part can have the form illustrated in  FIG. 2 . According to the first embodiment, the positioning means  500  are part of the circular part  101  and are placed along the periphery of the circular part  101 . 
         [0122]    The central part  111  comprises an opening  121  or cavity, adapted to accommodate a portion of a subcutaneous part  36 , essentially the portion of the subcutaneous part  36  which is not inserted or to be inserted in the patient&#39;s skin. The opening  121  may comprise attachment means for the subcutaneous part  36 , adapted to provide a non-releasable connection during use and the subcutaneous part  36  comprises corresponding means for attachment to the opening  121  and thereby to the site  100 . An embodiment of a subcutaneous part  36  according to the invention is shown in  FIG. 1C . 
         [0123]    The positioning means  500  generally comprises two or more openings or recesses in combination with protruding parts provided in a hard part of the infusion site  100 ; hard parts of the site are e.g. the circular part  101  as in the first embodiment or e.g. the central part although placement of the positioning means in this part is not illustrated by an embodiment. 
         [0124]    The positioning means  500  of the first embodiment are shaped like a symmetric toothed wheel having 10 teeth with rounded off openings or recesses provided in between the teeth. Each opening or recess has identical dimensions, and a given area comprising both an opening and a surrounding part of a protruding area fits closely to a corresponding area on the proximal side of the connector part  200 . The corresponding means for positioning  700  of the connector part  200  are adapted to fit into one or more of the openings of the positioning means  500 , whereby ten distinct and different relative positions of the connector part  200  in correspondence to the site  100  are possible. The toothed wheel will normally have 3-20 openings, thereby providing 3-20 different positions of the connector part  200  relative to the site  100 . 
         [0125]    The openings of the toothed wheel might have less rounded shape comprising straighter edges, such as triangular or rectangular openings. Accordingly, the means for positioning  700  will have a corresponding shape, such as a triangular or rectangular shape, respectively. 
         [0126]    The toothed wheel and the central part  111  can be attached to or be part of a base of a hard material i.e. the base, the circular part  101  comprising the toothed wheel and the central part  111  comprising the subcutaneously positioned part are moulded as one single piece which is afterwards attached to a surface material  300  having a non-adhesive upper or distal side and an adhesive lower or proximal side, or alternatively, the toothed wheel and the central part  111  can be provided individually and each part is then attached directly to a surface material having a non-adhesive upper or distal side and an adhesive lower or proximal side. 
         [0127]    In order to provide a reliable and releasable attachment of the connector part  200  to the site  100  during use, the site  100  comprises attachment means  400 . According to the first embodiment the attachment means  400  are provided on the circular part  101  which circular part  101  is essentially shaped like a hollow cylinder having upright walls essentially perpendicular to the surface material  300 . The profile of the inner surface of the upright wall is shaped as a reverse L i.e. an upside down L: ┌. This shape makes it possible for a part of the connector part  200  to hook around the profile. The same effect of providing an edge, around which a part of the connector part  200  can get hooked, can be provided if the inner surface of the upright wall is e.g. provided with an annular groove at the upper or distal part of the wall. The attachment means  400  are provided by a section of inner profile having a smaller diameter near the top. 
         [0128]      FIG. 15  shows a first embodiment of a connector part  200  according to the invention comprising a hard outer shell  131  having an inner cavity, adapted to encompass the site  100 . The outer diameter of the connector part  200  is normally slightly wider than the site  100 , but might be similar to or smaller than the outer diameter of the site  100 . Furthermore, the connector part  200  comprises means for attachment  600  corresponding to attachment means  400  of the site  100  and means for positioning  700  corresponding to positioning means  500  of the site  100 . When the corresponding attachment means  600  are activated, the connector part  200  can be attached releasably to the site  100  as the means for attachment  600  correspond to and/or interact with the attachment means  400  of the site  100 . The means for positioning  700  corresponding to the positioning means  500  will—when the connector part  200  is attached to the site  100 —provide that the connector part  200  is positioned in a distinct user-defined position relative to the site  100 . When combined, the means for positioning  700  of the connector part  200  and the positioning means  500  of the site  100  are adapted to define more than one distinct position for the connector part  200  in relation to the site  100  which positions the user can choose among when the user joins the two parts are together. 
         [0129]    The means for attachment  600  of the connector part  200  comprise actuating means  151 , retaining elements  141  and an elastic element  161 . The actuating means  151  comprises two arms positioned diametrically opposite each other and each arm is provided with an outward hook constituting a retaining element  141 . Each hook has a portion which upon release is caught under the protruding upper edge of the central opening and prevents the connector part  200  from moving away in a vertical direction. The two arms of the actuating means  151  form part of the outer periphery of the connector part  200  and will normally form a section with an increase diameter or cross-section which will make it possible for the user to feel exactly where to push in order to release/attach the connector part  200  from the site  100 . The elastic element  161  connects the two arms by one end of each arm. When the two arms forming the actuating means  151  are pressed towards each other, the elastic element will provide a spring action trying to return the arms to their original relaxed position. The three elements: actuating means  151 , retaining elements  141  and elastic element  161  could be moulded as a single element. 
         [0130]    By applying an inward directed pressure on the actuating means  151 , e.g. by pressing e.g. with two fingers, the distance between the retaining elements  14  is reduced to less than the maximum diameter of the top section of the circular part  101 , whereupon the connector part  200  can be attached to or removed from the site  100  as the retaining elements  141  can then pass through the opening provided by the top section of the circular part  101 . Upon release of the inward pressure and assisted by the action of the elastic element  161 , the retaining elements  141  move back into or towards the position, where the distance between the retaining elements  141  is increased to a distance greater than diameter of the top section of the circular part  101 . 
         [0131]    The connector part  200  comprises a central tubular element  181  through which a fluid can be delivered. The tubular element  181  is encompassed by a cylindrical wall  171  standing upright from the inner surface of the outer shell, the cylindrical wall  171  is provided with an opening through which a pipeline for fluid can pass. The cylindrical wall  171  provide guidance for the user in order to determine the correct position of the connector part  200  relative to the site  100  when the user pushes the connector part  200  towards the site  100 . 
         [0132]    The corresponding means for positioning  700  are two protrusions attached to or being part of the outer shell  131  and facing inwards toward the centre of the connector part  200 . The two protrusions are according to this embodiment positioned symmetrically opposite each other. Alternatively, the connector element can have an asymmetric distribution of protrusions and the connector element can also have only one, or more than two protrusions e.g. up to 10 protrusions. The protrusions could according to the invention be placed in any angle if the design of the actuating means  151  allows it. As mentioned above, the shape and position of the protrusion(s) are adapted to the positioning means  500  of the site  100 . 
         [0133]      FIG. 16A  shows a second embodiment of a medical device according to the invention, the medical device is as the embodiment illustrated in  FIG. 1  a device comprising a site  100  which can be combined with a subcutaneous part  36 . If the subcutaneous part  36  is a cannula part it comprises a disc like septum  900  blocking the entrance to the cannula which during use is positioned subcutaneously. The site  100  comprises two parts: a surface material  300  which during use is attached to the patients skin and a top part  191  which is attached unreleasably to the upper surface of the surface material  300  and which part is adapted to hold the subcutaneous part  36  and provide for the releasable attachment of a connector part  200 . The surface material  300  is normally made of a patch of weaved or non-weaved material and is adapted to be releasably attached to the patient&#39;s skin during use, e.g. by an adhesive surface facing the skin. The site  100  comprises positioning means  500  corresponding to positioning means  700  on a connector part, such a connector part  200  can have the form illustrated in  FIG. 4 . According to the second embodiment, the positioning means  500  are part of the top part  191  and are placed along the periphery of a central part of the top part  191 . 
         [0134]    This second embodiment also provides positioning means  500  similar to a toothed wheel when seen from the top. The toothed wheel has teeth and openings of a more rectangular shaped than the first embodiment and the vertical profile of the outer periphery of the toothed wheel is a straight line. The height of the openings between the teeth are not important when it comes to defining the distinct positions but can be relevant when it comes to making the connection between the connector part  200  and the site  100  stable as longer openings causing a longer and closer fit between the corresponding positioning means of the site  100  and of the connector part  200  in a vertical direction, will improve the stability of the connection. According to the second embodiment the outer diameter of the toothed wheel is just slightly larger than the central opening  121  for the cannula part  36  but alternatively the outer diameter could be larger, the optimal diameter is to some degree defined by the connector part  200  which is to be used together with the site  100 . 
         [0135]      FIGS. 16  B and D shows a third embodiment of an infusion site  100  according to the invention. The third embodiment comprises a toothed wheel with a bell shaped and/or sigmoid cross section. The sigmoid surface of the teeth can be essentially flat as shown in the figures, but said surface can also be more rounded and comprise further curvatures, such as a convex surface. 
         [0136]    According to the second and third embodiment of the sites, the attachment means  400  comprises a circular protrusion on the periphery of a flat circular base of a hard material which is attached to the surface material  300  of the site  100  i.e. the periphery of the flat circular base has a top section with an increased diameter under which a part of the connector part can get hooked and thereby lock the vertical movement of the connector part  200  relative to the site  100 . 
         [0137]      FIG. 17  shows a second embodiment of a connector part  200  according to the invention which can connect to the second and the third embodiments of the site. The connector part  200  comprises—like the first embodiment—a hard outer shell  131  having an inner cavity, adapted to encompass the site  100 . The outer diameter of the connector part  200  is normally slightly wider than the site  100 , but might be similar to or smaller than the outer diameter of the site  100 . Furthermore, the connector part  200  comprises means for attachment  600  corresponding to attachment means  400  of the site  100  and means for positioning  700  corresponding to positioning means  500  of the site  100 . When the corresponding attachment means  600  are activated, the connector part  200  can be attached releasably to the site  100  as the means for attachment  600  correspond to and/or interact with the attachment means  400  of the site  100 . The means for positioning  700  corresponding to the positioning means  500  will—when the connector part  200  is attached to the site  100 —provide that the connector part  200  is positioned in a distinct user-defined position relative to the site  100 . When combined, the means for positioning  700  of the connector part  200  and the positioning means  500  of the site  100  are adapted to define more than one distinct position for the connector part  200  in relation to the site  100  which positions the user can choose among when the user joins the two parts are together. 
         [0138]    The means for positioning  700  of the connector part  200  comprise elongated protrusions extending from the inner surface of the outer shell  131  in a vertical direction which protrusions are adapted to fit into the openings of the toothed wheel constituting the positioning means  500  of the site  100 . As shown in the figures, the protrusions are arranged in a circular fashion and are attached to or being a part of the outer shell  131 . When the protrusions are arranged in a circular fashion, the protrusions also work as guiding means helping the user to connect the connector part  200  to the site  100 . The protrusions may comprise a curved or inclined surface at the end in order to facilitate finding the appropriate, distinct position. In the shown embodiment, the numbers of protrusions extending from the inner surface of the outer shell  131  matches the number of openings in the toothed wheel providing the positioning means  500  of the site  100 . Alternatively, the number of protrusions might be smaller than the number of openings in the positioning means  500  but there should be at least one protrusion and at the most the number of protrusion should equal the number of openings in the positioning means  500 . A higher number of protrusions may increase or improve the stability of the assembly comprising the combined site  100  and connection part  200 . 
         [0139]    The means for attachment  600  of the connector part  200  comprise like for the first embodiment actuating means  151 , retaining elements  141  and an elastic element  161 . The actuating means  151  comprises two arms positioned opposite each other and an elastic element  161  connects the two arms by one end of each arm. Each arm is extended from the point of connection thereby turning each arm into a form for lever. Each arm extension is provided with an inward hook constituting a retaining element  141 . Each hook has a portion which upon release is caught under the protruding upper edge of the flat circular base of a hard material of the site  100  and prevents the connector part  200  from moving away in a vertical direction. The extension of the two arms of the actuating means  151  form part of the outer periphery of the connector part  200 . When the two arms forming the actuating means  151  are pressed towards each other the two arm extensions will be moved away from each other thereby increasing the distance between the two retaining elements, the elastic element will provide a spring action trying to return the extended ends of the arms to their original relaxed position. According to this embodiment the elastic element  161  might be made from a different material than the arms. 
         [0140]    When the distance between the two retaining elements is increased, it is possible to attach or remove the connector part  200  to/from the site  100 . When applying pressure to the actuating means  151  the load of the elastic element  161  in is increased. Inwards pressure is released the return of the actuating means  151  to their relaxed state is assisted by the action of an elastic element  161 , the retaining elements move back into their original position, whereby the distance between the retaining elements is reduced to a distance smaller than the outer diameter of the protrusion of the attachment means  400 . 
         [0141]      FIG. 18  shows top and bottom views of a device according to the invention relating to a leakage- and/or malfunction indication system. The four views shows a surface material  300  in the form of a round transparent plaster, in the central part of the plaster a round part of a hard non-transparent material is placed such as a top part to which a connector part  200  can be attached. Around the part of hard non-transparent material a ring-shaped section of the plaster is impregnated with a leak indicator  201  which shifts colour when it gets in contact with leaking medication such as insulin. The two left examples shows top views of the device; the two right examples show bottom views of the same device as shown to the left. 
         [0142]    Example A illustrates a “complete crawl out” where the cannula is no longer subcutaneously inserted but is positioned above the skin under the transparent plaster. The cannula might e.g. be coloured in a distinct colour e.g. blue or green, which is easily seen in contrast to the rest of the device. When a coloured cannula is applied, the cannula becomes visible through the transparent plaster during use and the patient is able to realise that the insulin input is not working correctly although the indication does not change colour. 
         [0143]    Example B illustrates a “partial crawl out” or “buckling/crimping” of the cannula. In this case the cannula is not visible through the transparent plaster but it is also not functioning as it should. When insulin reaches the edge of the hard non-transparent part, the leakage indicator will change colour. Thus, the patient will be able to realise that the cannula is malfunctioning and that the insulin input might be incorrect. 
         [0144]    The leak indicators might be used for any medication for which it is possible to produce a visible change. The leak indicators can be used with all embodiments of the present invention.