FIELD OF THE INVENTION

The invention relates to the technical field of injecting one or more implants into a patient's body.

BACKGROUND OF THE INVENTION

Implant injection devices, comprising a hollow needle attached to a housing receiving an implant, are known. The implant is injected using a pushing rod, which pushes the implant through the hollow needle then beyond to inject the implant into a patient's body.

In particular, document US20090281520A1 describes an implant injection device in which the implant can be injected by slidably pressing a button, the button then being pressed by the user in a direction substantially parallel to the injection direction. Thus, before actuation, the pushing rod is retracted and the button is located on the side of the proximal end of the device, in other words the end opposite the injection end. When the user slidably presses the button, the button slides in a direction substantially parallel to the injection direction and moves the pushing rod, which pushes the implant and allows its injection.

However, with such actuation by slidably pressing, the user is unable to inject several implants easily. This actuation is generally carried out by the user's thumb, which has a limited actuation stroke that is insufficient for the stroke required to inject a very long implant and/or for the successive injection of two or more implants. In addition, with such actuation, good injection accuracy cannot be maintained over a long stroke and in particular the injection cannot be stopped once the implant has been injected, for example to direct the injection needle in another direction for a second implant to avoid injecting too deeply. With such actuation, there is in fact a risk of accidentally starting to inject an implant after the implant already injected. This is not desirable to guarantee correct injection, in particular to avoid breaking at least one of the implants or injuring the patient.

Thus, in view of their actuation type, these implant injection devices cannot be used to easily inject a very long implant or a plurality of implants.

SUMMARY OF THE INVENTION

This invention aims in particular to provide an implant injection device which can be used to easily inject a very long implant and/or a plurality of implants. Thus, the invention relates in particular to an implant injection device comprising:an injection needle,a receiver housing for receiving at least one implant,injection means, the injection means comprising:a pushing rod, arranged upstream from the implant housed in the receiver housing, extending longitudinally and configured to push the implant through the injection needle between an initial position and a final position in which the implant is injected,means for actuation by a user, configured to actuate a displacement of the pushing rod from the initial position to the final position, the actuation means comprising a rack transmission mechanism.

Thus, it is proposed to produce an implant injector that is easy to handle and to assemble, by creating a transmission of movement that is pleasant for a user. Through one or more movements of small amplitude, the user can in fact actuate the pushing rod over a long distance using the rack transmission, in order for example to inject a very long implant or a plurality of implants.

It is understood that a rack transmission mechanism preferably comprises a straight toothed element cooperating with a gear to transform a rotation movement into a translation movement or vice versa.

An “implant” is preferably understood to mean a pharmaceutical compound in solid or semi-solid state, for example in the form of an encapsulated liquid and/or an electronic component, for example an RFID type electronic chip. A “patient” or “subject” is generally understood to mean a living being, for example a mammal, in particular a human being. The user is generally a person different from the patient but the user may be the patient himself.

In this description, it is understood that the distal direction designates the direction farthest away from a user's fingers, in other words closest to the skin or the surface of a patient at the time of an injection, and the proximal direction designates the direction opposite to the distal direction. In other words, it is considered that the distal direction and the distal sense are the direction and sense which go towards the “front” of the implant injection device, the direction also called the injection direction. In particular, the distal end of a part corresponds to the end located on the side of the injection needle and the proximal end corresponds to the opposite end. It is also understood that the injection axis, which is the injection direction, corresponds to the axis of the implant injection device defined by the axis of the injection needle.

Consequently, it is understood that the “downstream” direction is a direction opposite to the “upstream” direction and corresponds to the direction towards the distal end of the implant injection device, in other words towards the injection site, towards the end configured to be in contact with the implant injection site. Thus, the “downstream” direction may also be called the injection direction.

It is understood that the terms “upstream” and “downstream” designate the distal and proximal directions, respectively, a downstream element being arranged further away in the distal direction than an upstream element. The implant injection device may further comprise one or more of the following characteristics, taken alone or in combination.

The rack transmission mechanism comprises a first rack element and a second rack element,the first rack element being configured to be driven by the user and forming a first rack and pinion type link with a pinion, the pinion comprising a first set of gear teeth cooperating with the first rack element,the pinion comprising a second set of gear teeth cooperating with the second rack element, configured to push the pushing rod from the initial position to the final position.

Thus, a rack transmission mechanism comprising a pinion and two rack elements is proposed, to multiply the user's movement. In other words, by a sliding movement over a short distance, driving the first rack element, the user can actuate the pushing rod over a long distance, in order for example to inject a very long implant or a plurality of implants. Advantageously, the first and second sets of gear teeth of the pinion consist of a first gear and a second gear of the pinion, the diameter of the first gear being less than the diameter of the second gear.

The actuation means comprise an actuation button sliding in a direction substantially parallel to the longitudinal direction of the pushing rod, which is supported by the first rack element. Thus, the movement required to actuate the implant injection device is especially easy for a user, who can for example easily hold the implant injection device in one hand and actuate the pushing rod using the sliding actuation button, with the thumb of this hand.

The implant injection device comprises means for indicating a position of the pushing rod to the user. Thus, the user can easily check the position of the pushing rod and can, for example, stop actuating the pushing rod by using the indication supplied by the indication means, which is especially advantageous if a position corresponding to the end of injection of a first implant is indicated. This indicates to the user that he can remove the implant injection device or change the injection direction to inject a second implant at the same depth as the first implant.

The indication means comprise a first flexible tab carried by a unit, and the rack transmission mechanism comprising at least one projection, such that when the rack transmission mechanism reaches a first predetermined position, the projection is in abutment against the first flexible tab to give the user a first audible and/or tactile indication. Thus, when the rack transmission mechanism reaches a first predetermined position, the user detects via the audible and/or tactile indication, which is especially practical, that the rack transmission mechanism has reached this first predetermined position, which may, for example, correspond to a position in which an implant is injected. This can be used, for example, to indicate to the user that he must stop the injection when the injection of an implant is complete, for example to avoid injecting too deeply or to direct the injection needle in another direction for a subsequent implant such as a second implant, to avoid injecting too deeply.

The indication means comprise a second flexible tab carried by the unit, the second flexible tab being configured to abut against the projection in a second predetermined position preceding the first predetermined position, such that when the rack transmission mechanism reaches a second predetermined position, the projection is in abutment against the second flexible tab, and when the rack transmission mechanism goes past the second predetermined position, the second flexible tab crosses the projection in order to give the user a second audible and/or tactile indication. Thus, when the rack transmission mechanism reaches a second predetermined position, which corresponds to a position preceding the first predetermined position, the user detects via the audible and/or tactile indication that the rack transmission mechanism has reached this second predetermined position, which may, for example, correspond to a position preceding a position in which an implant is injected. This can be used for example to indicate to the user to slow down the injection when the injection of an implant is almost complete, to avoid injecting too deeply.

The bending strength of the first flexible tab is greater than that of the second flexible tab. Thus, the tactile and/or audible indication is different depending on whether the rack transmission mechanism has reached the second predetermined position or the first predetermined position. The second predetermined position may correspond to an intermediate actuation position in which a part of implant is still to be injected, and the first predetermined position may correspond to an actuation position in which an implant is injected. It is therefore useful that the bending strength of the first flexible tab should be greater than that of the second flexible tab, thereby allowing the user to easily detect that the implant is injected, to avoid injecting too deeply, or to direct the injection needle in another direction for a subsequent implant such as a second implant, to avoid injecting too deeply.

The receiver housing is adapted to receive a plurality of implants, the pushing rod, in the first predetermined position of the rack transmission mechanism, occupies a position in which an implant is injected. Thus, the user easily detects than the implant is injected, to avoid injecting too deeply, or to direct the injection needle in another direction for another implant, to avoid injecting too deeply.

The at least one projection comprises a tooth protruding from a flat longitudinal surface of the rack transmission mechanism. Thus, the indication means are extremely easy to produce.

The implant injection device comprises a unit, the pinion being pivotally mounted on the unit. Thus, the rack transmission mechanism is extremely easy to produce.

The number of teeth of the first set of gear teeth is strictly less than the number of teeth of the second set of gear teeth. Thus, multiplication of the user's movement is extremely easy to produce. In addition, for example, the number of teeth of the first set of gear teeth is between 5 and 15, preferably between 5 and 10, more preferably close to or equal to 5; and/or the number of teeth of the second set of gear teeth is between 6 and 30, preferably between 16 and 25, more preferably close to or equal to 18.

The ratio of the displacement of the second rack element to the displacement of the first rack element is between 2 and 10, preferably between 3 and 5, more preferably close to or equal to 3.6. Thus, multiplication of the user's movement is optimized. If the ratio of the displacement of the second rack element to the displacement of the first rack element is too high, the injection accuracy is affected, and if the ratio of the displacement of the second rack element to the displacement of the first rack element is too low, the amplitude of the movement to be produced for actuation by the user is too high.

The implant injection device comprises locking means arranged to block the pushing rod in its final position, position in which the pushing rod preferably projects towards the downstream direction past the end of the injection needle. Thus, the implant injection device is not reusable, thereby respecting hygiene constraints relating to this type of implant injection device. In addition, when in its final position, the pushing rod projects towards the downstream direction past the end of the injection needle, the pushing rod forms in this case a safety element for the end of the injection needle which may be beveled for easier insertion into the skin. The pushing rod can then prevent the needle from exerting its insertion function, for example on a person or an object if the implant injection device is dropped. Thus, if the implant injection device is dropped or pressed in the distal direction, the contact with the implant injection device is made via the pushing rod and not with the end of the injection needle.

