The invention relates to a tool for manipulating a solid object in a cavity of a human or animal body, comprising a rod member adapted for insertion into said body cavity, a first coupling member connected to one of the rod member and the object through a flexible filament, and a second coupling member connected to the other of the rod member and the object, said first and second coupling members being arranged for being mechanically coupled together through magnetic attraction.
The invention also relates to a drug administration set comprising such a tool.
Further, the invention relates to a method of drug administration.
More particularly, the invention is concerned with drug administration to non-human mammals, wherein the object to be manipulated is an intravaginal device, for example for administering drugs for controlling the reproductive cycle of a sow or gilt.
WO 2008/061963 A2 discloses a helically shaped drug supporting anchor that comprises a layered polymer fibre. The drug is contained in one of the layers of the fibre. The fibre is wound to a helix the outer diameter of which is slightly larger than the internal diameter of the vaginal cavity of the mammal to be treated, so that, thanks to its own restoration force, the helix will tend to expand and firmly engage the internal walls of the vaginal cavity so as to be retained therein. When the helix is retained in the vaginal cavity in this way, the drug will gradually be released from the fibre in suitable amounts.
U.S. Pat. No. 3,892,238 discloses a drug administration tool comprising a helically shaped drug supporting anchor and an insertion rod around which a fibre or string forming the drug supporting anchor is wound helically. The insertion rod has means for applying an additional torsional strain to the helix, so that the curvature of the fibre is increased and the outer diameter of the helix is reduced when the same is introduced in the vaginal cavity. Then, when the helix is in place, the torsional strain is relieved, so that the helix resumes its greater original diameter and is firmly held in the vaginal cavity.
After treatment, the drug supporting anchor has to be withdrawn from the vaginal cavity. It is essential that the withdrawal process can be performed with high reliability, because a too long drug exposure and/or a permanent presence of the drug supporting anchor in the vagina would be disadvantageous, e.g. because it would not allow breeding of the animal.
U.S. Pat. No. 3,805,777 discloses an intrauterine device in the form of an annular object, as well as a tool for withdrawing the annular object from the uterus. This tool uses magnetic attraction of the two coupling members for withdrawing the object.
U.S. Pat. No. 6,551,304 discloses a longitudinal apparatus for retrieving a remotely located device, in particular present in a cavity of the human body, using magnetic coupling forces. The magnetic poles are arranged such that a key member connected to the device is drawn into a recess of the apparatus along a longitudinal direction of the apparatus. The longitudinal direction of the apparatus coincides with the retrieval—and hence pulling—direction of the device. Given the fact that magnetic forces are too weak to ensure that the device remains coupled to the apparatus during retrieval, elements are provided at the distal end of the longitudinal apparatus to ensure mechanical grasping and locking of the key member. Comparable apparatus, employing elements to grasp and lock the key member are also known from U.S. Pat. No. 3,786,807 and EP 276 104.
DE 3403294 describes a tool which has the configuration described in the preamble of claim 1. The tool comprises a rod which has a plurality of shields to mechanically lock spherical key members when retrieving an intra-uterine device. The magnetic poles of the tool are arranged for drawing the spherical key member into the recess along a direction perpendicular to the longitudinal direction of the rod member. In order to ensure that the spherical key members remain locked behind the shields when retrieving the device, the shields are constituted as rigid curved shields. These shields therefore constitute barbs that may easily damage the internal wall of the uterus and cervix.
It is an object of the invention to provide a tool that permits to manipulate (e.g. to insert or extract) the object in the body cavity with high reliability and with a low risk of damaging the internal walls of the cavity.
In order to achieve this object, the tool according to the invention is characterised in that the key member and recess are constituted such that when the key member is drawn into the recess, an operative contact surface exists between the key member and the recess, the said contact surface extending in a direction perpendicular to the longitudinal direction of the rod member.
When the key member is accommodated in the recess, and the rod member is moved in a direction normal to the direction in which the recess opens, the two coupling members will be held together not only by magnetic attraction but also by form fit of the key in the recess, so that the forces transmitted from the rod member to the object can be significantly larger than the magnetic forces between the coupling members. It was surprisingly found that the use of an operative contact surface which extends in a direction perpendicular to the longitudinal direction of the rod member, instead of a contact point as known from the prior art (in particular DE 3403294), takes the need away to constitute the recess in the form of a curved shield. This significantly reduces the risk of damaging the internal walls of the body cavity. When the mechanical coupling is to be established, it is sufficient to bring the rod member into the vicinity of the object, so that the coupling members will magnetically attract one another. The flexible filament will permit the first coupling member to move under the influence of the magnetic forces and to automatically assume a posture in which the key member fits into the recess.
More specific optional features of the invention are indicated in the dependent claims.
The first coupling member may be connected, via the flexible filament, to the object whereas the second coupling member is formed at a distal end of the rod member, or vice versa. Similarly, the recess may be formed in the first coupling member while the second coupling member forms the key member, or vice versa.
When the recess is formed in the rod member, it is preferable that the recess opens in a lateral direction of the rod member, so that form fit between the recess and the key member will occur when the rod is moved in its longitudinal direction.
When the key member is the first coupling member, it is preferable that the second coupling member has a slot that opens into the recess and permits the flexible filament to pass through in a direction essentially in parallel with the plane of the opening of the recess.
In one embodiment, both, the first and the second coupling members are permanent magnets. In another embodiment, one of the permanent magnets, preferably the one connected to the rod member, may be replaced by an electro-magnet, so that magnetic attraction can be switched on and off. A coil of the electro-magnet may also be used for detecting whether the key member is properly accommodated in the recess, because the presence of the key member will cause a significant change in the inductivity of the coil. As an alternative, a separate sensor coil may be provided for that purpose.
In yet another embodiment, one of the first and second coupling members may be a permanent magnet or an electro-magnet, whereas the other coupling member is just a piece of magnetisable material.
A drug administration set according to the invention comprises the tool that has been described above, and a drug supporting anchor as the object to be manipulated. The drug supporting anchor may have a helical shape adapted to insertion into the vagina of an animal, and may be made of a material having a shape memory property. Then, the set will preferably comprise an insertion tool for inserting the drug supporting anchor into the vagina, said insertion tool being essentially formed by a rigid tube which accommodates the drug supporting anchor and confines the same to an extended configuration with reduced curvature. As a result, the tool may have a small outer diameter so as to avoid an injury of the animal during the insertion process. When the tube has been inserted into the vagina, the rod member of the withdrawal tool may be used for pushing-out the drug supporting anchor out through the distal end of the tube, whereupon the drug supporting anchor, thanks to its shape memory property, will re-assume its original helical shape, with the windings of the helix closely engaging the walls of the vagina.
In another embodiment, especially when the magnet in one of the coupling members is an electro-magnet that can be switched on and off, the rod member may also be used for inserting the helical drug supporting anchor into the vagina. For example, the helical drug supporting anchor may be provided with two magnetic key members connected to the opposite ends of the helix via respective flexible filaments. Then, the key member at the distal end of the helix may be used for inserting the drug supporting anchor into the vagina. When the electro-magnet is switched off, the rod member may be withdrawn whereas the drug supporting anchor remains in the vagina. Then, when the drug supporting anchor is to be removed again, the rod member will be inserted once again and the magnet will be switched on when the tip end of the rod member reaches the vicinity of the proximal end of the helix, so that the key member attached to that end will engage in the recess of the rod member.
Preferred embodiments will now be explained in conjunction with the drawings, wherein:
As is shown in
The tube 10 may be made of metal or plastics and is rounded at its tip end (on the left side in
The drug supporting anchor 12 is formed by a fibre or an extruded semi-rigid string 12′ of a polymer material that is impregnated with the drug to be administered to the gilt 18, e.g. a drug for controlling the reproductive cycle of the animal. The natural shape of the drug supporting anchor 12, i.e. the shape it assumes when it is not subject to any external forces, is that of a helical spring (a helix) the outer diameter of which is slightly larger than the internal diameter of the vagina 16 of the gilt. In the condition shown in
When the tube 10 has been inserted into the vagina 16 of the gilt 18, with the drug supporting anchor 12 accommodated in the tube, the rod member 14 will be inserted into the tube 10 from the rear end, so that the drug supporting anchor 12 is pushed out from the tip end of the tube. In the example shown, the rod member 14 has a cigar-shaped handle 24 which facilitates the manipulation of the rod member but has also another function that will be explained later.
The rod member 14 is not only used for pushing the drug supporting anchor 12 out of the tube 10, but forms also part of a tool for withdrawing the drug supporting anchor 12 from the vagina 16. As is shown in
As is shown in
When, now, the rod member 14 is withdrawn, the form fit between the key member 36 and the recess 30 assures that the force exerted onto the rod member 14 is transmitted to the key member 26 via the peripheral wall of the recess 30. As a result, the filament 28 is subject to a tensile force which causes the same to settle in the slot 32 of the handle 24 and to transmit the tensile force to the proximal end of the drug supporting anchor 12. As a result, the helical drug supporting anchor 12 will be drawn out to assume a stretched configuration with smaller diameter, so that it may smoothly be drawn out of the vagina 16.
The recess 30 in the handle 24 has a flat circular bottom face against which the key member 26 will be attracted. The circular contours of the recess 30 and the key member 26 permit the key member to rotate until the filament 28 is accommodated in the slot 32. Then, the peripheral wall of the recess 30 may exert a force onto the key member 26 tending to tension the filament 28, and the reaction force of the filament 28 will draw the key member 26 closer against the peripheral wall of the recess 30 in the direction in parallel with the longitudinal direction of the rod member 14 and the slot 32 and normal to the peripheral wall of the recess 30, so that the filament will not cause the key member 26 to be drawn out of the recess. In a preferred embodiment two recesses 30 are present in handle 24, one recess on either side of the magnet present in the hart of handle 24.
In the example shown in
The second coupling member is formed by a handle 24′ having an elongated recess 30′ that extends in longitudinal direction of the rod member 14 and is adapted to the elongated shape of the key member 26′. The handle 24′ is a permanent magnet that is magnetised such that its north and south poles N, S are formed by opposite axial ends of the elongated recess 30′.
When the key member 26′ is brought into the vicinity of the handle 24′, the elongated shape of the key member 26′ may cause the same to assume the orientation of the magnetic field around the recess 30′, so that the key member will fit into the recess. Further, the magnetic field will magnetise the material of the key member 26′, so that the latter is attracted into the recess.
In principle, it is possible in the embodiment shown in
The leads 44 are connected to a current source and switch (both not shown) and are further connected to a detection and indication device 45 that measures the inductivity of the coil forming the electro-magnet 42. If the key member 26″ is not properly seated in the recess of the handle 24″, then the inductivity will be smaller than usual, and this is indicated to the user by an acoustic or optical warning signal, e. g. by lighting an LED.
The key member 26″ is attached to the filament 28 in the same manner as in
In yet another embodiment, the key member 26′ shown in
In a modified embodiment, the bolt 48 may be formed in one piece with the cap 46 or embedded therein, and may have self-cutting threads to be screwed into the drug supporting anchor 12.
In yet another embodiment, the filament 28 may form a loop that passes through a transversal through-bore of the drug supporting anchor 12.
Finally,
In contrast, in the present invention (
Number | Date | Country | Kind |
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10150929.7 | Jan 2010 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP11/50499 | 1/17/2011 | WO | 00 | 7/16/2012 |
Number | Date | Country | |
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61296581 | Jan 2010 | US |