Implant syringe

Abstract

The invention relates to an implant syringe having a cannula, a storage element for receiving a solid material implant, an outer sleeve having a radially projecting front grip portion, and an inner sleeve, the inner sleeve having an axial slit, the implant syringe further having a rod-shaped piston, the rod-shaped piston is fixed to the rear grip portion and is partially surrounded by a rear sleeve, the rear sleeve being slidably engageable in the inner sleeve, and wherein the inner sleeve is composed of a front needle guard and a rear spacer which are locked together, characterized in that corresponding locking windows are formed in two opposing tabs on the needle guard, the spacer has two locking hooks at corresponding positions, and in order to connect the two components, the tab slides over the locking hooks on the spacer until the locking hooks are locked into the locking window.

Description

Technical Field

[0001] The invention relates to an implant injector for delivering a chain-shaped solid material implant with a long-acting active substance into a patient's body. The long-acting preparation is usually placed in the patient's abdominal wall, and a receiving channel for the solid material implant is pre-pierced into the patient's abdominal wall by means of a cannula. Background Art

[0002] The invention starts with an implant injector, which comprises the following features: a cannula, a storage element for receiving a solid material implant, an outer sleeve with a radially protruding front gripping portion, and an inner sleeve, the cannula and the storage element together with the outer sleeve being axially movable together with the front gripping portion, the outer sleeve being located on the inner sleeve, and the cannula and the storage element being slidable in the inner sleeve, wherein the inner sleeve has an axial slit, through which radial spacers on the outer sleeve engage, wherein the implant injector also has a rod-shaped piston, which is fastened to the rear gripping portion and is partially formed by the rear sleeve. Surrounded by, the rear sleeve is able to be slidably engaged in the inner sleeve, wherein the rod-shaped piston can be pushed into the cannula through the storage element in such a way that there is still a gap between the front end of the cannula and the head end of the piston, which gap is approximately equal to the length of the solid material implant to be delivered, wherein, when the cannula is exposed, the outer sleeve is releasably locked in the advancement starting position by a blocking device on the inner sleeve, and when the rear sleeve is pushed into its end position, the blocking device moves to the release position, whereby the outer sleeve can be retracted on the inner sleeve with the help of the front gripping part until the cannula is completely inserted into the inner sleeve.

[0003] This implant syringe is disclosed in DE102017007893A1. In this implant syringe, the outer sleeve is integrally connected to the needle holder by radial spacers, and the storage element receiving the solid material implant is inserted into the rear side of the needle holder. After the inner sleeve and the outer sleeve are assembled, the cannula is fixed in the front opening in the needle holder by an adhesive. The solid material implant is inserted into the storage element by the open rear side of the inner sleeve and is advanced to a slightly clamped starting position in the storage element by a rod-shaped piston. When the solid material implant is delivered to the patient using the implant syringe, the rear gripping part is then advanced together with the piston until the solid material implant has been advanced to the front end of the cannula, and the outer sleeve exposed in this position is retracted together with the cannula and the storage element thereafter, while the solid material implant is left in the patient.

[0004] From DE 10 20 20 12 2 654 A1 an implant injector is known in which a cannula is securely connected to a storage element to form a separate cannula unit, that is to say separated from the rest of the implant injector, whereby the insertion of a solid material implant into the storage element is greatly simplified. The invention further provides that a septum on the outer sleeve is attached at its radially inner end to an annular receiving member, which is located within the inner sleeve, and the cannula unit can be inserted into the receiving member together with the solid material implant inserted into the storage element and can be locked therein.

[0005] In these known implant syringes, the inner sleeve is made of two parts, namely the front needle guard and the rear spacer that lock together.For this purpose, two locking hooks are formed on the long spacer on the needle guard, and the locking hooks snap into the locking window in the spacer.

[0006] When tension acts on the locking connection, the locking hook is stretched, so that only a very small space is available for the locking hook due to the components. Preferably only about 1.5 mm is required due to the design. 2 With a cross section of 100 mm, the locking hook is only subject to a tensile force of approximately 10 N. However, a higher holding force of the snap connection and a more stable construction of the implant injector are desired. Since there is no more space for a locking hook with a larger cross section due to the components, it is not feasible to solve the problem by having a locking hook with a larger cross section without impairing the operability and visual appearance of the implant injector. Summary of the invention

[0007] It is therefore an object of the present invention to provide an improved locking connection by means of which the holding force is significantly increased.

[0008] According to the invention, this object is achieved by the features of solution 1.

[0009] Advantageous embodiments of the invention are characterized by further features.

[0010] The present invention provides that corresponding locking windows are formed in two diametrically opposed tabs on the needle guard component, and the spacer provides two locking hooks at corresponding positions. When the two parts are connected by a snap, the tab slides over the locking hooks on the spacer until the locking hooks are locked into the locking windows in the tab. Therefore, the end sections of the two tabs on the needle guard are received flush in the recesses in the spacer. Therefore, a stable, non-detachable snap connection is established on both sides, wherein when an attempt is made to separate the two parts by pulling them apart, the applied force is no longer absorbed by the stretching of the plastic material, but by the pressure on the plastic material. The holding force of the connection is thus significantly increased without increasing the outer circumference of the inner sleeve and without significantly changing its visual appearance.

[0011] In an advantageous embodiment of the invention, the two tabs providing the locking windows on the needle holder have different lengths, so that with a corresponding design of the two locking hook areas only a single assembly position of the two components is possible.

[0012] The locking hook preferably has a block-like wedge shape with an upper side that rises obliquely in the assembly direction and a rear side that is preferably undercut at a flat angle so that the snap connection is virtually non-detachable. The end section of the tab should engage flush in the recess in the spacer. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Further details will be apparent from the following description of a preferred embodiment of the implant injector with the aid of the accompanying drawings, in which:

[0014] Figure 1a and Figure 1b are different views of one embodiment of an implant injector;

[0015] Figure 2a and Figure 2b are different views of the rear sleeve with the rod-shaped piston;

[0016] Figure 3 is a view of an inner sleeve composed of a needle guard member and a spacer member;

[0017] Figure 4 A conventional needle guard member of the inner sleeve is shown;

[0018] Figure 5 The spacing member of the inner sleeve is shown;

[0019] Figure 6 An embodiment of an inner sleeve according to the present invention is shown;

[0020] Figure 7a and Figure 7b The needle guard and the spacer are shown in a separated state;

[0021] Figure 8 It is a cross-sectional view of the locked state of the inner sleeve. DETAILED DESCRIPTION

[0022] Figure 1a and Figure 1bThe initial state of the implant syringe is shown, wherein the syringe needle 1 is shielded by a removable protective cap 2. The removable protective cap 2 is lightly and releasably locked to the outer sleeve 3. The outer sleeve 3 has an elongated cylindrical shape, wherein a radially protruding front grip portion 4 is integrally formed at its end section (right side in the figure). The outer sleeve 3 is securely connected to the needle holder 6 by means of a plurality of radially inwardly extending spacers 5, in which the syringe needle 1 is fixed. The preparation receiving member 7 is axially configured after the needle holder 6 so that the channel 8 of the preparation receiving member 7 is aligned with the channel in the syringe needle 1. Located in the preparation receiving member 8 is a preparation (not shown), which is deposited, for example, in the abdominal wall of the patient when the implant syringe is used.

[0023] The outer sleeve 3 (when unblocked) is slidably located on the inner sleeve 9, which is composed of a front needle guard 10 and a rear spacer 11. The needle guard 10 includes a front conical taper 12, which is closed in the circumferential direction and shields the front end of the fully retracted syringe needle 1. The axially adjacent area includes circumferentially spaced spacers or tabs 13, wherein in the prior art, hooks 15 are formed on the end sections of the two spacers, and the hooks 15 are locked into the recesses in the spacer 11 of the inner sleeve 9 to connect the two parts ( Figure 4 and Figure 5 ).

[0024] The rear part 11 of the inner sleeve 9 comprises a resilient arm 17 which is cut out from the wall of the inner sleeve member 11 and projects radially outwards with a locking hook. As long as the rear sleeve 18 does not slide into the end position in the rear part 11 of the inner sleeve 9, this resilient arm 17 with the locking hook acts as a blocking device for the outer sleeve 3.

[0025] A flat gripping member 19 is integrally formed on the rear end of the rear sleeve 18, and a rod-shaped piston 20 is fastened to the gripping member 19 in the center of the sleeve 18. The rear sleeve 18 comprises a slit extending in the axial direction and cooperating with the elastic arm 17 by means of an inclined surface when the rear sleeve 18 slides into the rear spacer 11 of the inner sleeve, so that the locking hook of the elastic arm is pulled radially inwards. This is the case when the inner side of the rear gripping member 19 abuts against the rear edge 22 of the inner sleeve 9, wherein this position is lightly and releasably locked.

[0026] The outer sleeve 3 can here be retracted together with the injection needle into its end position, in which the two gripping members 4 and 19 engage with each other. The front end of the injection needle 1 is here located in the frustoconical section 12 of the inner sleeve 9.

[0027] Figures 6 to 8The embodiment of the locking of the inner sleeve 23 according to the present invention is shown, and the inner sleeve 23 is composed of a front needle guard 24 and a rear spacer 25. The needle guard 24 includes two elongated tabs 26, and two locking windows 27 are formed in the end area of ​​the tabs. Two locking hooks 28 are formed at corresponding positions on the spacer 25, and the locking hooks are snapped into the locking windows 27 when the needle guard 27 and the spacer 25 are assembled. The end area of ​​the tab 26 overlapping the spacer 25 is flushly moved into the recess 29 in the spacer 25.

[0028] The locking hook 28 has a substantially wedge-shaped, block-like structure. The upper side 29 of the locking hook rises obliquely upward in the assembly direction, while the rear side 30 of the locking hook 28 is undercut at a flat angle. The snap connection is thus stable and practically non-detachable.

[0029] The two tabs 26 with the locking windows 27 have different lengths, whereby the two associated areas of the locking windows are positioned correspondingly so that only one assembly position is possible.

Claims

1. An implant syringe, comprising a cannula, a storage element for receiving a solid material implant, an outer sleeve having a radially protruding front gripping portion, and an inner sleeve, wherein the cannula, the storage element and the outer sleeve can move axially together with the front gripping portion, the outer sleeve is located on the inner sleeve and the cannula and the storage element can slide in the inner sleeve, wherein the inner sleeve has an axial slit, and a radial spacer on the outer sleeve engages through the slit, the implant syringe also having a rod piston, the rod piston being fixed to the rear gripping portion and partially surrounded by the rear sleeve, the rear sleeve being slidably engaged in the inner sleeve, wherein the rod piston can The invention relates to a method for advancing an implantable solid material into the cannula through the storage element in such a way that a gap still exists between the front end of the cannula and the head end of the piston, the gap being approximately equal to the length of the solid material implant to be delivered, wherein, when the cannula is exposed, the outer sleeve is releasably locked in the advancement starting position by a blocking device on the inner sleeve, and the blocking device moves to a release position when the rear sleeve is advanced to its end position, whereby the outer sleeve can be retracted on the inner sleeve by means of the front gripping portion so that the cannula fully enters the inner sleeve, and wherein the inner sleeve is composed of a front needle guard and a rear spacer that are locked together, characterized in that Corresponding locking windows (27) are formed in two opposing tabs (26) on the needle guard (24), the spacer (25) has two locking hooks (28) at corresponding positions, and in order to connect the two components, the tabs (26) slide over the locking hooks (28) on the spacer (25) until the locking hooks (28) are locked into the locking windows (27).

2. The implant injector according to claim 1, characterized in that In the snap-fit ​​connection, an end section of the web (26) engages flush in a recess (29) in the spacer (25).

3. The implant injector according to claim 1 or 2, characterized in that The locking hook (28) has a substantially blocky wedge shape with an upper side (29) which rises obliquely in the assembly direction and a rear side (30) which is undercut at a straight angle so that the snap connection is non-releasable.

4. The implant injector according to any one of claims 1 to 3, characterized in that The two tabs (26) have different lengths and the two regions of the locking window (27) are correspondingly designed, so that only one assembly position is possible.

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