FIELD OF THE INVENTIONThe present invention relates generally to an implanting device for inserting implantable objects beneath the skin of a patient. More particularly, the present invention relates to an implanting device which provides improved control of implantable object release due to an angled track located on the base of the implanting device.
BACKGROUNDDrugs may be delivered to patients by a variety of methods including oral intravenous administration, inhalation of aerosols, an epidermal patch, and subcutaneous implants. The method chosen depends, among other things, upon the desired therapeutic concentration of the drug or pharmaceutical to be achieved in the patient and the duration the concentration must be maintained.
Recently released materials and pharmaceuticals have been developed which allow a drug to be subcutaneously introduced or administered beneath the skin of a patient so that the drug is slowly released over a long period of time. Such implants allow a drug to be dispensed in a relatively uniform dose over many months or years. This method of administering drugs is becoming especially important and popular as a method of administering contraceptives.
Previously, subcutaneous implants and other types of implants have been inserted beneath the skin by use of a trocar system, which is a two piece system including a cannula and an obdurator. First, an incision is made through the skin and the cannula and obdurator are inserted together through the skin. Next, the obdurator is withdrawn, leaving the cannula in place as a guide for inserting the implant. The implant is inserted through the cannula, and the obdurator is used to push the implant to the end of the cannula. The obdurator is then used to force the implant out of the cannula while the cannula is withdrawn, such that the implant is deposited in the channel previously occupied by the cannula. The cannula and obdurator are then withdrawn completely, leaving the implant in place beneath the skin.
This trocar insertion process requires substantial expertise in coordinating the pressing of the obdurator and the withdrawing of the cannula to deposit the implant in the channel. If these two processes are not properly coordinated, the implant may be forced into the tissue so that the implant has to make its own channel as it is inserted. Forcing the implant into the tissue causes additional trauma to the tissue and may cause the implant to become damaged by the force exerted by the obdurator. This is especially true for a hydrogel implant. While subcutaneous implantation may be done surgically using a scalpel to make the incision and a trocar system to place the implant, such methods require a physician or other highly trained person. Recently improved instruments for inserting subcutaneous implants have been developed which typically require far less skill to operate, and thus may be better suited for non-surgical physicians and other less skilled individuals, and require less time to perform the implantation procedure.
U.S. Pat. No. 4,105,030 discloses an implanting apparatus for use in subcutaneously implanting multiple pellets in animals. The apparatus provides a one-handed implanting system that reduces the risk of trauma from forcing the implant into the tissue, and it also reduces contamination. The animal implant apparatus includes a handle, a needle containing the pellets to be implanted, and a rod positioned within the needle for pushing the pellets out of the needle. Once the needle containing the pellets has been inserted subcutaneously, a spring loaded trigger on the handle is activated which causes the needle to be automatically withdrawn by a spring leaving the implanted pellets in place. However, the handle configuration of this implanting device is designed for use in animal, such as cattle, and due to its size and shape, it would be difficult to use for inserting implants subcutaneously in humans. Further, it is not possible to control the motion of the needle in this device because the needle will automatically retract upon activation of the trigger. The complex spring loaded propelling system and trigger of this implant apparatus increase the chances that the device will jam and fail to eject the pellets when required.
Contraceptive steroids that are implanted subcutaneously are normally imbedded in biologically inert polymers, some of which are biodegradable. The pellets made from such materials are typically long and cylindrical in cross section, and the size of these materials is on the order of the size of a pencil lead. The materials are generally flexible, ranging from somewhat flexible to very flexible in nature. See, for example,
US Pat. No. 4,451,253, which describes some exemplary contraceptive pellets and an apparatus for individually implanting such pellets subcutaneously.
WO 99/33512 describes an implanting apparatus comprising an actuator on a non-flexible track pivotally connected to a cannula by a base and pin arrangement. The actuator slides longitudinally and imparts longitudinal movement to the cannula.
US Pat. No. 4,661,103 describes a cannula complexed with a laterally extending magazine able to feed multiple implants into the cannula. All of the components of injection are arranged to move along the axis of the cannula.
The size and shape of an implant pellet are important in determining the rate of delivery of a particular drug from a subcutaneous implant. Practical considerations put constraints on the dimensions of a subcutaneous implant.In particular, the length of an implant is generally limited. A typical implant is on the order of 3.8 - 5.1cm (1½ to 2 inches) long. Longer implants are much more difficult to accurately locate. They are also more susceptible to breakage, which may affect the drug delivery rate and, in general, are simply more cumbersome and cosmetically apparent. Because of this, it is frequently necessary to implant a desired amount of a drug as a plurality of individual, shorter implant pellets rather than as a single longer pellet. Thus, an instrument which can quickly allow a physician or nurse to implant a plurality of pellets with minimal physical and psychological trauma to a patient would be desirable. When implanting several implants, care must be taken to accurately place the implants in a manner such that one does not interfere with the dissolution of the others.
SUMMARYEmbodiments of the present invention include a device which may be used for implanting various pharmaceuticals and therapeutic drug delivery devices. Such implantable objects may include those such as silicone rubber capsules or tubes that contain a synthetic progestin birth control hormone. The flexible tubes may steadily release a low dose of hormone into the bloodstream.
The device according to the invention is as defined in the claims. One embodiment of the present invention is an implant device for inserting implantable objects subcutaneously into a patient, comprising a handle for grasping the device during insertion of an implantable object and a base connected to the handle. The base comprises a post, a cannula, and a flexible actuator positioned in an angled track. The cannula is positioned coaxially around and is longitudinally slidable over the post from an extended position, where an implantable object is retained in the cannula, to a retracted position, where the implantable object is released from the cannula. A flexible actuator positioned on an angled track in the base is slidably engaged with a boss on the cannula and is used to move the cannula from an extended position to a retracted position to release the implantable object from the cannula; the actuator flexes between a locked and an unlocked position.
The flexible actuator of the implant device may be locked to prevent movement of the cannula and thereby prevents any undesired dispensing or insertion of implantable objects. By pressing the flexible actuator into a second position (when the actuator is in the track in a distal position with respect to the handle) a locking portion of the actuator is engaged to prevent retraction of the cannula. The lock may be released by alternately pressing the flexible actuator to a first position.
The implanting device may further include one or more implantable objects within the cannula. The implanting device may also include a cartridge for holding multiple implantable objects that are sequentially fed into the cannula after an implantable object is dispensed by movement of the actuator and cannula. The cartridge may be removably mounted and have a channel containing an implantable object that is parallel to a central bore of the cannula.
A subcutaneous implantable object can be inserted with an implanting device of the present invention by inserting a cannula of the implanting device beneath the skin of a patient with an implantable object positioned within the cannula and manually retracting the cannula along the angled track using the flexible actuator to release the implantable object beneath the skin. The implanting device may then be withdrawn from the patient or another implantable object from a cartridge positioned within the cannula may be subsequently inserted. The implanting device used in the method includes a handle, a base, and a cannula slidably engaged with a flexible actuator located in an angled track.
An implanting device according to the invention may be provided as part of a kit with a cannula; a cutting device for making an implanting incision in a patient's tissue; supplies for maintaining sterility of the implant insertion process; and wound dressings.
The implantable object and implanting device of the present invention may be useful for insertion of implants coated with a sol-gel coatings or with hydrogel implants. The active agent may be slowly released by the implant or the coating on the implant when placed in watery environments such as blood or tissue. The device may be used to implant any such implant.
The present invention provides embodiments of an implanting device for inserting implantable objects which provides improved control of implantable object release due to the angled track located on the base of the implanting device. The flexible actuator is positioned on the angled track, which helps to prevent the forcing of the implantable object into the tissue, as such uncontrollable forcing can cause trauma to the tissue and may cause the implant to become damaged.
DESCRIPTION OF THE DRAWINGSIn part, other aspects, features, benefits and advantages of the embodiments of the present invention will be apparent with regard to the following description, appended claims and accompanying drawings where:
FIG. 1 is an isometric view of an implanting device according to the present invention with the cannula retracted and the flexible actuator is in an unlocked position;
FIG. 2 is an isometric view of the implanting device with the cannula in a fully extended position with the flexible actuator in a locked position;
FIG. 3 is an exploded view of an implanting device according to an embodiment of the present invention.
FIG 3A is a further view of the device ofFIG. 3 and references hereinafter is "Figure 3" or "FIG.3" also referenceFIG. 3A.
FIG. 4 is a side view of an implanting device according to the present invention with the cannula in a fully extended position with the flexible actuator in a locked position;
FIG. 5 is a top view of an implanting device according to the present invention with the cannula in a fully extended position with the flexible actuator in a locked position.
DETAILED DESCRIPTIONBefore the present compositions and methods are described, it is to be understood that this invention is not limited to the particular molecules, compositions, methodologies or protocols described, as these may vary. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present invention which will be limited only by the appended claims.
It must also be noted that as used herein and in the appended claims, the singular forms "a", "an", and "the" include plural reference unless the context clearly dictates otherwise. Thus, for example, reference to a "cell" is a reference to one or more cells and equivalents thereof known to those skilled in the art, and so forth. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, the preferred methods, devices, and materials are now described.Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.
The present invention provides an implanting device for subcutaneously inserting implantable objects containing beneficial agents, such as pharmaceuticals for the prevention, treatment, and diagnosis of disease. The implanting device200 according to one embodiment of the present invention is illustrated in the perspective view inFigure 1. The implanting device200 includes a handle220, a movable elongated cannula240 (shown in a retracted position), a flexible actuator button262 connected to a flexible actuator260 (shown inFIG. 3) for moving the cannula240 along a post rod244 (shown inFIG. 3), and a base280. The base280 is distal to the handle end222. In the retracted position, the cannula240 is drawn into the interior of the handle base280 by the flexible actuator button262 as it is moved or slid toward the handle end. The flexible actuator button262 is guided by an angled track300 which is non-parallel with respect to the axis of motion of the cannula240 or the axis of the post rod244 (shown inFIG. 3). The cannula240 may be slid or moved with respect to the post rod244 (shown inFIG. 3) and housing base280 with cannula guide340. Movement of the flexible actuator260 in a direction toward the cannula guide340 and along the track300 away from the handle220 results in extension of the cannula240 through the cannula guide340.
InFigure 2 the implanting device200 is shown with the cannula240 in an extended position. InFIG. 2 the flexible actuator button262 is shown distal to the handle end222. In this position the flexible actuator may be locked to prevent withdrawal of the cannula240 and unintended insertion of implantable objects. Movement of the flexible actuator button262 in a direction away from the cannula guide340 and along the angled track300 towards the handle220 causes retraction of the cannula240 and release of an implantable object (not shown) positioned within the bore242 of the cannula.
Motion of the flexible actuator is along an angled ramp which provides increased precision in control of the movement of the cannula along the post rod axis. This provides the user with the advantage of greater control of insertion of implantable objects.
With respect toFigure 3 there is shown an exploded isometric view of the embodiment shown inFigures 1 and2. In this Figure, the implanting device200 is shown in two portions200a and200b, which includes a handle220 having first and second portions220a and220b, a base280 having first and second portions280a and280b; a cannula guide340 having first and second cannula guide portions340a and340b; and a handle end222 including handle end portions222a and222b. The angled track300 is formed from two opposing recessed track walls300a and300b which, when the portions200a and200b of the implanting device are assembled, form the angled track300. Within the implanter handle220 are portions of a flexible actuator channel248a, (and248b in handle220b not shown inFIG. 3), which, when assembled, form a flexible actuator channel248 for guiding the tab268 of the flexible actuator within the assembled implanter handle220.
The flexible actuator260 inFigure 3 includes a button262, a boss channel272, a lower guide post264 (not shown inFIG. 3), lower guide post266, thin profile guide270, and tab268. The button260 is seated in the scoop310. The boss channel272 receives the guide posts362 and364 from the cannula boss360. Movement of the flexible actuator260 along the angled track300, in the direction away from the cannula guide340 and toward the post boss retainer248, allows cannula boss guide posts362 and364 within the boss channel272 to remain at a constant position relative to the post244, while the boss channel272 moves relative to them and at the same time pulls the cannula240 toward the post retainer248. The boss channel272 engages the cannula boss guide posts362 and364 and permits a pulling or pushing force to be exerted on the cannula240, for extension and retraction, as the flexible actuator260 is moved along the angled track300.
Flexible actuator guide post266 and flexible actuator guide post264 (not shown inFigure 3) are attached to flexible actuator260 and rest on top of angled guide ramp350b (not shown inFigure 3) and angled guide ramp350a respectively. An angled guide ramp350 is formed by joining guide ramp portion350a shown inFigure 3 and guide ramp portion350b (not shown inFigure 3) together. The flexible actuator guide posts264 (not shown inFigure 3) and266 shown inFigure 3 move parallel to the angled guide ramp350b (not shown inFigure 3) and angled guide ramp350b respectively translating movement of the flexible actuator260 along the angled track300 into movement of the boss channel272 perpendicular to the axis of the cannula240 as the flexible actuator260 is moved toward or away from the post retainer248. Cannula boss guide posts366 (not shown inFigure 3) and368 lie below linear guide352a and352b (not shown inFigure 3) and on top of base step354a and354b (not shown inFigure 3) maintains the cannula in a substantially fixed orientation with respect to the base280.
The degree to which movement of the flexible actuator260 between any two points along the guide ramp350 is translated into linear motion of the cannula242 along the post244 depends upon the angle of the base guide ramp350. The greater the angle that the base guide350 makes with respect to the post244, the more control that may be exerted over lateral movement of the cannula240. The shape of the base guide ramp portions350a inFigure 3 and350b (not shown inFigure 3) may be a linear or curvilinear.
Post244 is coaxially located within cannula bore242 and is secured to the housing base280 by post retainer248 through post boss246. The post244 is inserted into the end of the cannula242 where the cannula boss360 is located and protrudes through cannula guide340 which provides support and alignment for the post244. The diameter of the cannula guide340 is made so that movement of the cannula260 into and out of the base280 along the post244 occurs without binding or restriction of the cannula240 with the inner diameter of the cannula guide340. The diameter of the cannula guide340 may also be sized so that it prevents entrainment of fluids, particles, and other debris adhering to the cannula240 from being drawn into the implanter base280.
Figure 4 shows a side view of the implanting device of the present invention with the cannula in an extended position. InFigure 4, the flexible actuator button262 is shown distal to the handle end222. In this position, the flexible actuator may be locked to prevent withdrawal of the cannula240 and unintended insertion of implantable objects. Movement of the flexible actuator button262 in a direction away from the cannula guide340 and along the angled track300 towards the handle220 causes retraction of the cannula240 and release of an implantable object (not shown) positioned within the bore242 of the cannula240.
Figure 5 shows a top view of the implanting device of the present invention with the cannula240 in an extended position. InFIG. 5, the flexible actuator button262 is shown distal to the handle end222. In this position, the flexible actuator may be locked to prevent the withdrawal of the cannula240 and unintended insertion of implantable objects. Movement of the flexible actuator button262 in a direction away from the cannula guide340 and along the angled track300 towards the handle220 causes retraction of the cannula240 and release of an implantable object (not shown) position within the bore242 of the cannula240.
The implanting device may be made from molded, cast, machined components or combinations of these. For example the implanter portions200a and200b may be molded from chemically and mechanically suitable plastics such a polyvinylidine fluoride (PVDF) or ultrahigh molecular weight polyethylene (UPE). The cannula240 may be made from a variety of surgically acceptable stainless steels or titanium alloys, and the post may be made using similar materials or plastics like PVDF.
The implanter handle220 includes a grasping portion and may fit into the palm of the users hand. The handle is substantially symmetrical so that the implanting device can be used by either right or left handed users. Extending from the handle is a base portion 280 which includes a track300 in which a flexible actuator260 slides to extend or retract the cannula240. The track is formed by two opposed track side walls300a and300b angled with respect to the device post244, and that form a slot extending through the track300 along a length of the track to receive the actuator260 and thin profile guide272.
The cannula240 includes a boss fitting at an end proximal to the handle220 of the device. The cannula boss360 is secured around the proximal end of the cannula240 and provides guide posts264 and266 that fit into a channel on the flexible actuator260. The cannula boss360 may be attached to the cannula240 in any known manner such as by insert molding, press fitting, adhesive bonding, threading, ultrasonic staking, and the like.
The flexible actuator260 includes a channel which receives the cannula boss guide posts362 and364 and allows them to slide and move within the channel. The flexible actuator260 has a thin profile guide270 which extends through the slot in the track300 and guides the flexible actuator260 in the track300 as it slides longitudinally along the track. The thin profile guide270 of the flexible actuator is connected to an actuator button262 for engagement by a user's finger to move the actuator along the angled track300. The actuator button262 may have a ridged, grooved, or knurled slip surface which may be engaged by the user's thumb.
A longitudinal axis passes through a center of the cannula240 and the post244 in the base of the implanting device. The track along which the flexible actuator260 moves is not parallel to this axis along one or more portions of the track; the track may be linear or curvilinear. The track has a distal portion which provides a stop for the flexible actuator and also permits securing of the flexible actuator which locks the cannula in the initial loaded position and prevents unintended release of the implantable object from the device. The flexible actuator260 is released from the locked position by pressing the flexible actuator button262. When the flexible actuator260 is in the locked position a substantial force may be applied longitudinally on the distal end of the cannula240 without causing the cannula to retract.
Once the flexible actuator260 has been unlocked, further manual pressure on the actuator button262 in the direction toward the handle220 causes the flexible actuator to slide along the track. As the actuator slides in the direction of the handle, the cannula240 is withdrawn over the post244 and one or more implantable objects held stationary by the post244 may be released from the cannula240. The flexible actuator260 allows the user to manually control the motion of the cannula260 throughout the implant insertion process. The angle or slope of the track with respect to the axis of the post permits the user to exert greater control over the motion of the cannula than could be achieved using a linear track to guide the withdrawal of the cannula.
Although the implanting device is preferably a single use device, the implanting device according to the present invention may also be made for reuse. The reusable embodiment of the implanting device will preferably be formed of an autoclavable material known to those skilled in the art for sterilization and reuse.
The post244 is positioned within the base280 and is fixed within the proximal end of the base by a post retainer248. The post has a protrusion or boss at one of its ends which engages and secures the post244 to the post retainer248. The post retainer248 is secured to an interior surface of the implanter base. The distal end of the post244 is configured to engage the implantable object as the cannula240 is retracted over the post244. This distal end of the post244 may have a flat leading edge for engaging the implantable object or may also take on other configurations depending on the particular implantable object to be inserted. Some other distal end configurations include but are not limited to blunt, beveled, concave, and convex end surfaces.
The post244 preferably has an outer diameter which is somewhat smaller than an inner diameter of the cannula240 to provide clearance through the cannula tube and limit binding or restriction of the post within the cannula. The post diameter with respect to the cannula should limit the amount of material that can bypass the cannula and become entrapped within the base.
The handle of the present invention is designed for one handed operation with the handle grasped by the hand while the thumb is used to slide the flexible actuator in the angled track. The handle preferably has a size and shape that can be easily manipulated during implant insertion. The orientation of the handle relative to the cannula allows the user to firmly grip the handle, yet easily keep the handle parallel to the skin surface to prevent the cannula from diving into other tissue or piercing out through the skin during insertion. The implanting device includes a bottom surface of the base which is substantially planar and parallel to the cannula.
A distal tip of the cannula240 may be formed at various beveled angles, such as between about 30 degrees and about 45 degrees, or at a sharp point, such as 27 degrees which can cut skin. The preferred design of the cannula tip is a design with a beveled tip which does not cut unbroken skin and does not require special sharps disposal. The cannula of the implanting device is preferably inserted into the patient through a small incision made in the patient's skin to minimize scaring.
In operation the implanting device may be loaded with an implantable object either manually or with a cartridge. An incision is made at an implantation site and the cannula is inserted through the incision to a desired depth. Preferably, a depth indicating marker, such as a ring, is provided on the cannula to assist in locating the implantable object at a particular depth. Once the cannula is placed under the skin at a desired location for the implantable object, the flexible actuator is drawn back manually causing the cannula to be withdrawn over the implantable object and the post. When the cannula has been fully withdrawn, the implanting device is withdrawn from the patient leaving the implantable object in place.
The two handle portions and base portions may be assembled in any known manner such as by ultrasonic welding, adhesive bonding, press-fit bosses, or a snap fit. A rear surface of the handle rests against the palm of the user to steady the implanting device as the thumb moves the flexible actuator along the angled track. Pressure may also applied to the base by the index finger of the user during insertion of the cannula.
The assembly of the implanting device will be described with reference to the exploded view, which illustrates the implanting device prior to assembly. A cannula240 with boss 360 secured to it is slid over a post244 and the flexible actuator260 is slid onto the upper cannula boss guide posts. This subassembly is oriented in one portion of an implanting device so that the proximal end of the post244 is secured to a post boss retainer248. Next, the flexible actuator260 may be received within the actuator channel, the lower cannula boss guide post is positioned below the linear guide within the base, and the cannula 240 with the post244 inside of it is received into a cannula guide portion. Placement of the second implanter portion over the first implanter portion with the previously described subassembly positioned inside of it, traps the cannula, its guide posts, and the flexible actuator and its guide posts between cutouts in the second portion of the implanter.
When the implanting device is assembled, the flexible actuator260 is slidably connected to the upper cannula boss guide posts mounted to the cannula240. The flexible actuator260 slides along the angled or curvilinear track300 from a distal portion of the track which serves as a locking position to the proximal end of the track.
The present invention may be used in a kit which may include additional parts along with an implanting device which may be combined together to implant therapeutics, pharmaceuticals, or microencapsulated sensors into a patient . The kit may include the implanter in a first compartment. A second compartment may includes a syringe, needles, scalpel, and any other instruments needed. A third compartment may includes gloves, drapes, wound dressings and other procedural supplies for maintaining sterility of the implanting process, as well as an instruction booklet. A fourth compartment may include additional cannula and posts. A cover of the kit may include illustrations of the implanting procedure and a clear plastic cover may be placed over the compartments to maintain sterility.
Embodiments of the present invention include a device which may be used for implanting various pharmaceuticals, therapeutic drug delivery devices such as silicone rubber capsules that contain a synthetic progestin birth control hormone, or encapsulated microsensors. The angled guide track of the device permits finer control of the cannula motion during implantation which aids in the proper positioning of implants within the patient. Embodiments of the present invention contain fewer parts than other implant devices.
Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, other versions are possible. Therefore the scope of the appended claims should not be limited to the description and the preferred versions contained within this specification.