Element indwelling device using a cannula

Abstract

To deposit a solid medicament.SOLUTION: A device comprises a cannula 12 and a plunger 16. The cannula 12 comprises: a tip 18 provided at a distal end; and an attachment 20 which receives a proximal region of the cannula and has primarily one or more ribs 24, 26, 28 extending transversely, in particular perpendicularly, to a longitudinal axis of the cannula. The plunger 16 comprises a grip 38 and is partially slidable inside the cannula 12. The grip 38 has rib-like retaining elements which extend in a longitudinal direction of the plunger 16 and so as to be spaced apart from the plunger 16. Each of the rib-like retaining elements is connected to the plunger 16 by means of a connecting element and the connecting element can be severed at least in one of its end regions by interacting with the attachment 20.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention is particularly aimed at the placement of elements such as solid formulations or inserts, and comprises a cannula and a plunger. The cannula has a tip provided at the distal end and a fixture that houses the proximal region of the cannula and mainly has at least one rib extending transversely, particularly perpendicularly, to the longitudinal axis of the cannula. A plunger with a grip is at least partially slidable inside the cannula. The present invention relates to a device.

Background Art

[0002] In human and veterinary medicine, injection devices are used to place solid formulations or inserts that can be the subject of, for example, animal identification or monitoring. Corresponding devices are known, for example, from WO 2013 / 167431 pamphlet or EP 2314342 specification. In this case, in order to protect the applicator of the element, there is a possibility of fixing the plunger, which can also be called a mandrel after the placement of the element, that is, the cannula tip is covered by the plunger, thereby eliminating the risk of injury.

[0003] From DE 102012104058 specification, it can be seen that if a cannula has a mandrel arranged slidably and an engaging hook extends therefrom, and the distal end of the mandrel covers the cannula tip, the hook engages with the recess of the cannula holder.

[0004] The subject of DE 102013112324 specification is a cannula with a mandrel whose position is fixed by interaction with the tip of the cannula.

[0005] From US 2017 / 0065805 specification, a puncture instrument with a mandrel protruding from the tube tip is known.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Pamphlet of International Publication No. 2013 / 167431 [Patent Document 2] Specification of European Patent Application Publication No. 2314342 [Patent Document 3] Specification of German Patent Application Publication No. 102012104058 [Patent Document 4] Specification of German Patent Application Publication No. 102013112324 [Patent Document 5] Specification of US Patent Application Publication No. 2017 / 0065805 [Summary of the Invention]

[0007] In particular, the present invention has a problem of developing the device of the type described at the beginning so that injury by the cannula tip is prevented when it is no longer intended for use. According to a further aspect, there is a possibility that the device may be used multiple times to place the element.

[0008] Also, according to a further aspect of the present invention, the user can easily determine whether the plunger has been moved to a position where it is intended to cover the tip or has been moved to a position where the tip is already covered.

[0009] In order to solve at least one of the above aspects, according to the present invention, there are protruding fixing elements extending longitudinally of the plunger and spaced apart from the plunger, starting from the base provided on the grip of the plunger. It is basically considered that each fixing element is connected to the plunger via a connecting element, and the connecting element is separable by interaction with a fixture in at least one of its end regions. In particular, it is considered that the connecting element is separably and articulatedly connected to the fixing element and the plunger, or vice versa.

[0010] Depending on the structure of the grip used for the sliding of the plunger in this regard, on the one hand, a fixed element, which can also be called a tang seat, acts as a stopper together with the connecting element connecting to the plunger, enabling multiple uses. On the other hand, if a force acts on the grip in the direction of the distal region of the cannula, there is a possibility of separation from the fixed element. At this time, during further sliding of the plunger, since the connection between the fixed element and the plunger, especially the articulated connection, still exists, it is oriented parallel to the plunger along the interaction with the fixture. Therefore, the fixed element poses no danger in the application area. At the same time, the fixed element, which is approximately hook-shaped, interacts with the engagement receiving part of the fixture, especially the first rib, and engages by fitting into the rear part, as a result, uncontrolled withdrawal of the plunger from the cannula is impossible. Therefore, the cannula tip is continuously covered by the plunger.

[0011] In this regard, it is considered that the fixed element particularly has an engaging portion extending distally in the direction of the plunger rod, thereby resulting in a hook-like shape.

[0012] In particular, it is considered that the connecting element is connected to the engaging portion.

[0013] It is preferably considered that the connecting element is articulated to the plunger. In that case, of course, there is also a possibility of an articulated connection with the fixed element, and in that case, the connecting element is separable from the plunger.

[0014] The present invention also considers that the connecting element is separable at both ends, that is, one is the connection region for the fixed element and the other is the connection region for the plunger.

[0015] So that the connecting element can be reliably and problem-free separated from the engaging element, the present invention further provides that the fixture ProximalConsider that it has a hollow cylindrical portion with an outer diameter D, and that the inner width of two engaging portions facing each other in the diametrical direction with respect to the longitudinal axis of the plunger rod is equal to or approximately equal to D. Thus, if the plunger is slid in the direction of the fixture, the hollow cylindrical portion directly acts on each connection region between the connection element and the fixing element, enabling problem-free separation. The opposite side is connected to the plunger itself via a film hinge, so that when the plunger moves further into the cannula, the connection element adheres to the plunger and enters the gap between the hollow cylindrical portion and the plunger.

[0016] By the natural recommended solution, consider that the grip can be connected to the fixture by screwing, and that the length of the plunger is adjusted according to the length of the cannula such that the tip is not covered by the plunger in the first position where the fixture and the grip are in contact but not screwed together, and the distal end region of the plunger covers the tip in the second position where the fixture and the grip are screwed together.

[0017] In this case, the present invention is particularly characterized in that the fixture and the grip are engaged in the second position. The engagement can be formed such that it is perceptible tactilely and / or aurally.

[0018] There is a possibility that the grip has a male thread that interacts with the female thread present in the fixture to screw the grip and the fixture together.

[0019] Alternatively, the present invention considers that the grip has a female thread that interacts with a protrusion protruding from the fixture, particularly its proximal edge region, such as a luer lock protrusion, or the male thread of the fixture.

[0020] The base of the grip of the plunger mainly has a cylindrical shape on its circumferential surface. In particular, it is considered that the diameter of the circumferential wall of the base is smaller in the end region than in the central region, enabling problem-free gripping.

[0021] The outer surface of the fixing element can transition linearly to the peripheral surface of the base.

[0022] The grip itself can be a plastic injection molded product.

[0023] According to the theory of the present invention, depending on whether a single solid preparation or insert is to be retained using the cannula, or a plurality of such elements are to be retained continuously, after the use of the cannula, that is, after removal from the organism, it is ensured that the tip of the cannula is covered so that the risk of injury is avoided.

[0024] In this case, the cannula fixture and the grip of the plunger, which can also be called a mandrel, can be structurally formed such that two predetermined positions of stop and connection are perceptible tactilely and / or aurally.

[0025] With the plunger in a position where it does not cover the tip of the cannula, further sliding of the plunger in the direction of the tip of the cannula is stopped. This stop can be established by a connecting element between the fixing element and the plunger.

[0026] Alternatively, the stop is jointly effected by these interactions prior to screwing together the grip and the fixture. If the tip of the cannula is to be covered, the stop is overcome and the fixing element interacts with an engaging element such as a rib of the fixture, or by overcoming a protrusion such as a step during screwing, in particular the engagement of the fixture and the grip takes place at a second predetermined position.

[0027] Further details, advantages and features of the present invention will become apparent not only from the claims, the features discernible from the claims - individually and / or in combination - but also from the following description of the preferred embodiments discernible from the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] [Figure 1]Figure of a cannula with a protective cover and a plunger in the incorporated state. [Figure 2] Figure of a cannula with a plunger based on Figure 1, but with the protective cover removed. [Figure 3] Figure based on Figure 2, showing the cannula when the plunger is being pulled out. [Figure 4] Figure of a cannula with the plunger removed and a detailed view of the plunger. [Figure 5] Figure of the cannula when an element to be indwelled is inserted. [Figure 6] Schematic diagram and cross-sectional view for explaining the loading of an element into the cannula. [Figure 7] Figure of the cannula containing an element and its cross-sectional view when the plunger is inserted. [Figure 8] Figure of the cannula containing the plunger before indwelling the element. [Figure 9] Figure of the cannula when the element is being indwelled. [Figure 10] Figure of the cannula containing the plunger after indwelling the element. [Figure 11] Figure of the cannula containing the plunger before the safety mechanism is activated. [Figure 12] Figure of the cannula containing the plunger in motion for fixing. [Figure 13] Figure of the cannula, i.e., its fixture, and the fixed plunger. [Figure 14] Figure of a further embodiment of the cannula with a plunger and a protective cover in the incorporated state. [Figure 15] Figure of a cannula with a plunger based on Figure 14, but with the protective cover removed. [Figure 16] Figure of a cannula with the plunger removed. [Figure 17] Figure of the cannula at the position where the plunger is aligned with the cannula when the element is inserted into the cannula. [Figure 18] It is a diagram of a cannula including a plunger when placing an element. [Figure 19] It is a diagram of a cannula in which the plunger covers the tip of the cannula.

Mode for Carrying Out the Invention

[0029] From FIGS. 1 to 13 in which the same reference numerals are used for the same elements, in particular, an apparatus 10 for placing an element such as a solid preparation or an insert such as an individual identification or monitoring chip can be discerned. For this purpose, an apparatus 10 is used which comprises a cannula 12 for injecting an element 14 into a living being and a plunger 16 - also called a mandrel - which pushes the element 14 and causes it to pass through the cannula 12.

[0030] FIG. 1 shows the apparatus 10 in the stowed state.

[0031] In FIG. 2, the cannula 12 has a distal tip 18 and the proximal region is received in a fitting 20 consisting of a hollow cylindrical base body 22, from the peripheral wall of which ribs project in this embodiment and are partly provided with the reference numerals 24, 26, 28 (FIG. 3). A wing-shaped grip 30 is located in the distal region of the fitting 20 so that the operation can be carried out without problems. In this sense, the cannula 12 with the fitting 20 has a well-known structure.

[0032] On the outer surface of the cannula 12, marks 32, 34 may be provided to confirm the penetration depth of the cannula tip 18 into the living being.

[0033] In the stowed state, the cannula 12 is surrounded by a protective cover 36, which is removed before use. The protective cover 36 may be connected to the wing-shaped grip 30 via a predetermined breaking position, for example.

[0034] Proximally, the plunger 16 has a grip 38 for gripping the plunger so that the cannula 12 of the plunger 16 can be pushed into and, if necessary, pulled out of the cannula. The latter is done when a plurality of elements are to be successively placed using the cannula 12.

[0035] Spaced from the grip 38, a plurality of protrusions 40, 42, 44, mainly evenly distributed circumferentially, project from the circumferential surface of the plunger 16. Since the protrusions 40, 42, 44 enable the plunger 16 to be fixed by frictional fastening inside the cannula 12, uncontrolled slippage during transportation cannot occur. The protrusions 40, 42, 44 are located in the proximal end region of the plunger 16 and thus the cannula 12 when the plunger 16 is pushed into the cannula 12 (Figure 4).

[0036] In Figure 1, the device 10 in the incorporated state is shown, in which case the protective cover 36 has already been removed in Figure 2.

[0037] Figure 3 clarifies the position where the plunger 16 is pulled out of the cannula 12 for inserting the element 14, as is fundamentally clear from Figure 5.

[0038] In Figure 4, the plunger 16 with the grip 38, as well as the knob-like protrusions 40, 42, 44 that can fix the plunger 16 by frictional fastening inside the cannula 12, can be recognized in detail again.

[0039] In Figure 5, the state where the element 14 is manually pushed and moved inside the cannula 12 is shown in detail. For this purpose, the user can use the thumb to push the element 14 until it reaches the proximal opening of the fixture 20, and as a result, the element 14 is partially already placed inside the cannula 12 according to the lower figure in Figure 6.

[0040] After insertion of element 14, plunger 16 is inserted into the proximal opening of fixture 20 to slide element 14 longitudinally down cannula 12 toward tip 18, in order to push element 14 through cannula 12 and then place it therein, as shown in FIG.

[0041] In FIG. 8, plunger 16 has already been pushed past cannula 12 to a certain extent so that the distal end of element 14 protrudes beyond tip 18. In FIG.

[0042] In FIG. 9, the plunger 16 is pushed into the cannula 12 to a certain extent, so that the element 14 can be placed. For this, the length of the plunger 16 - or more precisely the plunger rod - and the cannula 12 with the attachment 20 are adjusted to one another so that the distal end 46 of the plunger 16 does not protrude beyond the tip 18, which starts from the beveled tip. In this position, the grip 38 of the plunger 16 cooperates with a front edge 48 extending towards the opening of the attachment 20 by means of a stop emerging from the plunger. For this, the grip 38 has in this embodiment two protruding parts 50, 52, which extend diametrically with respect to the longitudinal axis of the plunger and which may be called noses, which extend in the longitudinal direction of the plunger 16 and at a distance from the plunger, as is clear from the description of the figure.

[0043] The protruding portions 50, 52 emanate from a base 51 having a cylindrical shape of the grip 38, as can be clearly seen in the figure. The base 51 has a smaller diameter in its central region than at its edges, so as to be able to be gripped securely without slipping off.

[0044] Parts 50, 52, which may also be referred to as lugs or noses, are connected to the plunger 16 via connection projections 54, 56, that is, generally via connection elements. In this case, the connection is made such that the connection projections 54, 56 are connected to the lugs 50, 52 via a predetermined breaking position, while the connection between the connection projections 54, 56 and the plunger 16 is made via a kind of film hinge. At this time, the connection projections 54, 56 project from hooked protrusions 58, 60 extending in the direction of the plunger 16, and the protrusions extend in the direction of the plunger 16 from the ends of the lugs or noses 50, 52. At this time, the inner width of the hooked protrusions 58, 60 is approximately equal to the outer diameter in the region of the proximal opening of the fixture 20.

[0045] Of course, the present invention is not abandoned when the connection projections 54, 56 are connected to the plunger 16 via a predetermined breaking position and to the fixing elements 50, 52 via a film hinge.

[0046] If the element 14 is to be placed multiple times using the cannula 12, after the placement of the element 14, the plunger 16 is pulled back in order to insert a new element 14 in the manner described above and then place it. In that case, by acting as a stopper, the connection projections 54, 56, which may also be referred to as stop elements, ensure that the protruding fixing elements used as engaging elements, that is, the noses 50, 52, cannot interact with one of the ribs of the fixture 20 in the manner described below and fit into the rear part, thereby preventing the engagement of the plunger 16 as would otherwise be observable from FIG. 13.

[0047] In order to enable such engagement, since the edge of the opening of the fixture 20 acts on the connection regions of the connection protrusions 54, 56, which are used as stoppers before, to the hook-shaped protrusions 58, 60, a force must act on the grip 38 of the plunger 16 in the direction of arrow 64 (FIG. 11) so that the connection protrusions are substantially sheared in this region. Nevertheless, the connection protrusions 54, 56 are not lost because they remain articulatedly connected to the plunger 16 according to the invention, and when the plunger 16 penetrates into the fixture 20, i.e., into its passage opening, according to FIG. 12, the protrusions 54, 56 remain in the gap between the opening of the fixture 20 and the plunger 16 while maintaining their connection to the plunger by being bent in the direction of the plunger 16, as is apparent from FIG. 13. At the same time, the engagement hooks 58, 60 fit in the embodiment into the bottom of the fixture 20 of the cannula 12, i.e., the rear part of the first rib 24 (FIG. 13).

[0048] The user not only perceives this tactilely. In addition, a perceptible sound is generated by the connection protrusions 54, 56 being broken off from the protruding fixing elements, i.e., the noses 50, 52, which also indicates to the user that the safety function is activated to engage the plunger 16 with the fixture 20 using the noses 50, 52 so that an uncontrolled withdrawal from the cannula 12 cannot occur.

[0049] It should be mentioned that the present invention is not limited by the ribs 24, 26, 28. If the device 10 is no longer intended to be used, one or more other elements that protrude from or are integrated with the fixture 20 may be provided to ensure the engagement of the plunger 16.

[0050] From FIGS. 14 to 17, a further embodiment of the device 100 can be seen in which the element 114 is intended to be placed in the same way as in the device 10. Using this device, it is ensured that at the same time, by means of structurally simple measures, the risk of injury during the use of the device 100 is eliminated. In this case, if the use for the placement of a plurality of solid formulations or inserts is planned, it is intended that the device 100 provides the possibility of continuously placing a plurality of elements 114 into the body.

[0051] FIG. 14 shows the device 100 in the stowed state, and FIG. 15 shows the device 100 after the protective cover 136 surrounding the cannula 112 has been removed.

[0052] Similar to the embodiments of FIGS. 1 to 13, the cannula 112 has a tip 118 distally and, proximally, a fixture 120 with ribs extending perpendicular to the longitudinal axis of the cannula 112 in this embodiment. Some of the ribs are labeled with reference numerals 124, 126, 128. Of course, the ribs 124, 126, 128 are not an essential feature of the fixture 120.

[0053] In this embodiment, in order to place an element 114 such as a solid formulation or an insert using the cannula 112, the element needs to pass through the cannula 112 and through the distal region and be pushed out beyond it. For this purpose, a plunger 116, which can also be called a mandrel, is used. Proximally of the plunger 116, there is a grip 138 so that it can be gripped, inserted into the cannula 112, and slid in the longitudinal axis direction thereof.

[0054] According to the invention, the fixture 120 has a hollow cylindrical portion 122 with an internal thread 130 proximal thereto. The formation of an external thread 140 adapted to the internal thread 130 in the distal region of the grip 138 enables the grip 138 to be screwed onto the fixture 120. This is done when, after the solid preparation 114 has been placed, the cannula 112 is no longer to be used further and its tip 118 is to be covered by the distal end region of the plunger 116, as can be seen in FIG. 19. At this time, the length of the plunger 116 is adjusted according to the length of the cannula 112 provided with the fixture 120, so that when the grip 138 is screwed into the fixture 120 and mainly engaged with it at the end position, as is apparent from FIG. 19, the distal end region of the plunger 116 projects beyond the tip 118.

[0055] The device 100 according to the invention provides the user with two predetermined positions between the plunger 116 and the cannula 112. The first position is where the grip 138, i.e., its distal edge region 139, abuts against the start of the thread of the internal thread 130, i.e., the position where no rotational movement occurs between the grip 138 and the fixture 120. In this position, which can be seen in FIG. 18, the plunger 116 is slid within a certain range inside the cannula 112, so that the solid preparation 114 can be placed.

[0056] The second position exists when the grip 138 and the fixture 120 are screwed together. When the grip 138 is fully screwed into the fixture 120, engagement is effected by overcoming a locking element such as a protrusion before, so that reverse rotation of the screw is no longer possible. As a result, the cannula tip 118 is maintained covered by the plunger 116, thus eliminating the risk of injury to the user.

[0057] As is apparent from the figure, the proximal hollow cylindrical portion 122 has a slot 123 extending in the longitudinal axis direction of the cannula 112 through which the solid preparation 114 can be inserted.

[0058] This embodiment shows a grip 138 with a male thread 140 and a fixture 120 with a female thread 130. Of course, in that case, a structure can also be selected in which the grip 138 has a female thread in its hollow cylindrical portion extending distally, which cooperates with the male thread or protrusion of the fixture 120 to enable screwing. The invention described in the original claims of the present application is appended below. [1] A device (10) for the purpose of retaining an element (14), particularly a solid preparation or an insert, comprising a cannula (12) and a plunger (16), said cannula having a tip (18) provided at the distal end and a fixture (20) that houses the proximal region of the cannula and has one or more ribs (24, 26, 28) extending mainly transversely, particularly perpendicularly, to the longitudinal axis of the cannula, and said plunger having a grip (38) is partially slidable inside the cannula, wherein said grip (38) has protruding fixing elements (50, 52) extending in the longitudinal direction of the plunger (16) and spaced apart from the plunger, and each fixing element is connected to the plunger via connecting elements (54, 56), and said connecting elements are separable by interaction with the fixture (20) at least in one of their end regions, characterized in that it is a device. [2] The device according to [1], characterized in that said connecting elements (54, 56) are separably and articulately connected to the fixing elements (50, 52) and the plunger (16), or vice versa. [3] The device according to [1] or [2], characterized in that said connecting elements (54, 56) cooperate as a stopper with the proximal edge (48) of the fixture (20) for the purpose of using said device (10) multiple times, particularly for retaining an element (14). [4] The device according to at least one of [1] to [3], characterized in that said fixing elements (50, 52) have engaging portions (58, 60) extending in the direction of the plunger (16). [5] The device according to at least one of [1] to [4], characterized in that the distal end of the plunger (16) protrudes beyond the tip (18) of the cannula (12), and in a state where the plunger is engaged, said connecting elements (54, 56) are separated from the fixing elements (50, 52), and in a state where the connection with the plunger (16) is maintained, it is oriented parallel along the plunger. [6] The device according to at least one of [1] to [5], characterized in that the engaging parts (58, 60) are fitted to the rear part of an engaging element such as a rib (24) of the fixture (20). [7] The distal end of the plunger (16) protrudes beyond the tip (18) of the cannula (12), and in a state where the plunger is engaged, the connecting elements (54, 56) are separated from the plunger, and are mainly oriented parallel along this while maintaining the connection with the fixing elements (50, 52). The device according to at least [1]. [8] The device according to at least [1], characterized in that the connecting elements (54, 56) are separable from both the plunger (16) and the fixing elements (50, 52) by the interaction with the fixture (20). [9] The device according to at least one of [1] to [8], characterized in that the connecting elements (54, 56) are connected to the engaging parts (58, 60).

[10] The distal part of the fixture (20) is formed as a hollow cylindrical part with an outer diameter D, and the inner width of two engaging parts (58, 60) facing diametrically with respect to the longitudinal axis of the plunger is equal to D or approximately equal to D. The device according to at least one of [1] to [9].

[11] The device according to at least one of [1] to

[10] , characterized in that the fixing elements (50, 52) extend from a base (51) having an outer shape with a cylindrical end region of the grip (38) of the plunger (16).

[12] The device according to at least one of [1] to

[11] , characterized in that the outer surface of the fixing elements (50, 52) transitions linearly to the peripheral surface of the base (51).

[13] The device according to at least one of [1] to

[12] , characterized in that the connecting elements (54, 56) are connected to the plunger (16) or the fixing elements (50, 52) via a film hinge.

[14] An apparatus (100) for the purpose of implanting an element (114), particularly a solid preparation or an insert, comprising a cannula (112) and a plunger (116), the cannula having a tip (118) provided at its distal end and a fixture (120) that houses the proximal region of the cannula and has one or more ribs (124, 126, 128) extending laterally, particularly perpendicularly, to the longitudinal axis of the cannula, and the plunger provided with a grip (138) being partially slidable inside the cannula, wherein the grip (138) is connectable to the fixture (120) by screwing, and in a first position where the fixture and the grip are in contact but not screwed together, the tip (118) is not covered by the plunger, and in a second position where the fixture and the grip are screwed together, the length of the plunger (116) is adjusted to match the length of the cannula (112) such that the distal end region of the plunger covers the tip.

[15] The apparatus according to at least

[14] , characterized in that the fixture (120) and the grip (138) are engaged in the second position.

[16] The apparatus according to at least

[14] , characterized in that the grip (138) has a male thread (140) that interacts with a female thread (130) present inside the fixture (120).

[17] The apparatus according to at least

[14] , characterized in that the grip (138) has a female thread that interacts with a protrusion protruding from the fixture (120), particularly its proximal edge region, such as a luer lock protrusion, or a male thread of the fixture.

[18] The apparatus according to at least one of [1] to

[17] , characterized in that at least one protrusion (40, 42, 44) protrudes from the plunger (16), mainly in its proximal region, enabling frictional engagement with the inner surface of the cannula (12).

[19] The apparatus according to at least one of [1] to

[18] , characterized in that a plurality of protrusions (40, 42, 44) protrude from the plunger (16) and are evenly distributed around the peripheral wall. The apparatus according to at least any one of [1] to

[19] , characterized in that the plunger (16) provided with the grip (38) is a plastic injection molded product.

Claims

1. An apparatus (100) for the purpose of retaining an element (114) such as a solid preparation or an insert, comprising a cannula (112) and a plunger (116), wherein the cannula comprises a tip (118) provided at the distal end and a fixture (120) for accommodating the proximal region of the cannula, and the plunger provided with a grip (138) is partially slidable inside the cannula, wherein the grip (138) is connectable to the fixture (120) by screwing, and in a first position where the fixture and the grip are in contact but not screwed together, the tip (118) is not covered by the plunger, and in a second position where the grip is screwed to the fixture and the fixture is locked by overcoming a locking element, the distal end region of the plunger covers the tip, avoiding the risk of obstruction from the tip and making reverse rotation of the screw impossible, and the length of the plunger (116) is adjusted according to the length of the cannula (112), characterized by the apparatus (100).

2. The apparatus (100) according to claim 1, wherein the grip (138) has a male thread (140) that interacts with a female thread (130) present in the fixture (120).

3. The apparatus (100) according to claim 1, wherein the grip (138) has a projection protruding from the proximal edge region of the fixture (120), such as a luer lock projection, or a female thread that interacts with a male thread of the fixture.

4. The apparatus (100) according to any one of claims 1 to 3, wherein at least one protrusion (40, 42, 44) that enables frictional fastening with the inner surface of the cannula (112) protrudes from the plunger (116).

5. The apparatus (100) according to any one of claims 1 to 4, wherein a plurality of protrusions (40, 42, 44) are evenly distributed around the peripheral wall and protrude from the plunger (16).

6. The apparatus according to any one of claims 1 to 5, wherein the plunger (116) provided with the grip (138) is a plastic injection molded product.

7. The locking element of the apparatus (100) according to claim 1 is a protrusion.

8. The protrusion of the apparatus (100) according to claim 7 is a step.

9. The apparatus (100) according to claim 1, wherein the fixture (120) has one or more ribs (124, 126, 128) extending laterally with respect to the longitudinal axis of the cannula.

10. The apparatus (100) according to claim 9, wherein the ribs extend perpendicular to the longitudinal axis of the cannula.

11. The apparatus (100) according to claim 4, wherein the protrusions (40, 42, 44) protrude from the plunger (116) in their proximal region.

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