WO2021175880A1

WO2021175880A1 - A marked thread

Info

Publication number: WO2021175880A1
Application number: PCT/EP2021/055243
Authority: WO
Inventors: Joonas Mikkonen; Tero Jalkanen; Mikko Virtanen; Taina TJÄDER; Karym EL SAYED; Juliane SCHÖNDORF
Original assignee: Bayer Oy
Priority date: 2020-03-06
Filing date: 2021-03-03
Publication date: 2021-09-10

Abstract

The present invention relates to a method for marking a removal thread (4, 8, 12, 14, 16) of an intrauterine system (3), the removal thread having a length L, the method comprising using laser marking. The invention also relates to use of laser marking for marking a removal thread of an intrauterine system, as well as to the intrauterine system itself.

Description

A MARKED THREAD

FIELD OF THE DISCLOSURE

The present disclosure relates to removal threads of intrauterine systems (IUS), and especially to removal threads that are marked in order to help the healthcare professional during the insertion process of the IUS. The disclosure also relates to a method of marking the removal threads as well as to intrauterine systems comprising such marked removal thread.

BACKGROUND Intrauterine systems (IUS) have removal threads attached to them, to facilitate their removal after the IUS needs to be replace or otherwise removed. The removal thread, typically in two parts, is attached to the IUS and pass through the cervical canal. After insertion of the IUS, the threads are cut such that about 2-3 cm are left outside the cervix. Before insertion of an IUS, the healthcare professional uses a sound to measure the combined depth of the uterus and the length of the cervical canal, as it may vary significantly from one person to another, for example from 4 to 10 cm. After insertion, the position of the IUS can be checked using ultrasound or another imaging method, as the correct position of the IUS is crucial. Indeed, a wrongly positioned IUS may penetrate the uterine wall or be expulsed prematurely.

However, ultrasound may not be always available, or the healthcare professional doing the insertion may not be skilled to use it. It would thus be beneficial to be able to distinguish cases where the IUS is at its correct depth from those where it may be incorrectly positioned, so that in the latter cases, the position of the IUS may then be checked by ultrasound. For the time being, the inventors are not aware of any means capable of helping the healthcare professional without the use of ultrasound. Therefore, in light of the foregoing discussion, there exists a need to provide an IUS which correct positioning can be quickly assessed at least in a preliminary manner. OBJECTS AND SUMMARY

The present disclosure seeks to provide an intrauterine system which positioning in the uterus can be quickly assessed after insertion, at least on a preliminary manner and without use of ultrasound or other similar equipment. Another aim of the disclosure is to provide a method for marking a removal thread of an intrauterine system. Thus, an aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in prior art.

The present disclosure relates to a method for marking a removal thread of an intrauterine system, the removal thread having a length L, the method comprising using laser marking.

The present disclosure further relates to use of laser marking for marking a removal thread of an intrauterine system.

The present disclosure still further relates to an intrauterine system comprising a removal thread, wherein the removal thread comprises at least one visual marking to indicate insertion depth of the intrauterine system.

Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow.

It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those skilled in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following drawings wherein:

Figure 1 schematically illustrates an IUS after insertion into a uterus. Figure 2 shows a marked removal thread according to an embodiment.

Figure 3 shows a marked removal thread according to another embodiment.

Figure 4 shows a marked removal thread according to a further embodiment. Figure 5 schematically shows an IUS with a removal thread in two parts, according to an embodiment.

Figure 6 illustrates a scale sticker according to yet another embodiment. DETAILED DESCRIPTION

The present disclosure relates to a method for marking a removal thread of an intrauterine system, the removal thread having a length L, and the method comprising using laser marking. Embodiments of the present disclosure thus substantially eliminate or at least partially address the aforementioned problems in the prior art, and lead to an IUS with a removal thread or threads, which have a visual marking that helps the health care professional to quickly and easily check whether the IUS is in its correct position, without the need for an ultrasound measurement or similar. Indeed, when a scale or other visual marking is incorporated directly to the removal threads, it allows the health care professional to make a rough estimate about the position of the IUS in the uterus, right after insertion and without any imaging techniques. While the present disclosure does not intend to replace ultrasound examination fully, it may be used either in instances where ultrasound is not readily available or to give an indication that an ultrasound examination should be carried out.

In this description, the term removal thread is both in singular and in plural. Typically, the IUS is equipped with one removal thread which is attached to the IUS at its middle, for example by a knot, and the remaining ends are equalised. Thus, the removal thread is a single thread, in two parts and therefore it is often also referred to in plural. The embodiments and variants explained here apply mutatis mutandis to IUS's with one removal thread as well as two or more removal threads. Also, the terms removal thread and thread can be used interchangeably, and have the same meaning. A scale is to be understood as being a graduation, not necessarily with any numbers but with lines or other repeating, visual patterns, that have a given distance one from another. Laser marking is a category of methods to leave marks on an object, which also includes colour change due to for example chemical or molecular alteration, charring or melting. Laser marking may use an additive which changes colour when subjected to laser light, also called laser active agent. Laser engraving, which is a subset of laser marking, is the practice of using lasers to engrave an object, usually by melting or charring its surface.

Some possible additives that can be used and that changes colour when subjected to laser light are courmarin (2A/-chromen-2-one), fluorescein (3',6'-dihydroxyspiro[isobenzofuran-l(3A/),9'-[9^]^xaⁿthen]-3-one), polyphenyl, rhodamines (6G, 123 and B) and umbelliferone (7- hydroxycoumarin). It is also possible to use additives as described in WO 03/055684, such as a mixture of copper potassium iodide (CUKI3) or copper iodide (Cul) with a substance selected from zinc sulphide (ZnS), barium sulfate (BaS), alkyl sulfonate (for example RS02Na or R-

0S02Na), thioester (substances containing -SH) or mixtures thereof. Some further possible laser additives are listed in Tunable Lasers Handbook, F. J. Duarte (ed.), Optics and Photonics, Academic Press Inc. 1995, pages 200-213. Some suitable additives are marketed under the tradename of Mevopur® by Clariant International Ltd.

The additive is typically homogenously mixed within the material of the thread before pulling the material into thread-form, and the amount of additive can be for example 1-4 wt-% of the total weight of the material. The additive can be provided in the form of a masterbatch, comprising the polymer used for the thread, as this ensures a homogenous distribution of the additive in the final thread. The additive may also be a mixture of a laser active pigment or substance on a carrier polymer. In this case, the carrier polymer is preferably the same as used for the wire, to ensure good compatibility and mixing. According to an embodiment, the removal thread of the intrauterine system thus comprises an additive capable of changing colour when subjected to a laser light, and the laser light is applied on a selected part of the length L of the removal thread. Thus, during the manufacturing, either the removal thread can be irradiated with a laser light only on desired locations, or a mask may be positioned on the thread, so that only unmasked portions are illuminated. The additive used is thus a laser marking additive, which needs to be biocompatible and non-toxic.

The distribution of the portions or areas on which laser light is applied can be selected according to the needs. It is for example possible to apply the laser light on a number of selected parts of the removal thread, such that selected parts and unselected parts alternate along the length L of the removal thread. Thus, the selected parts will have a different colour than the unselected parts, making a striped thread. In another embodiment, only a portion close to the IUS is irradiated with laser light, i.e. laser marked, such that it forms a "warning portion", giving an indication that the IUS is positioned too low inside the uterus. This could be used both directly after insertion but also during use of the IUS. Indeed, the length of the cervical canal does not vary as much as the depth of the uterus from one person to another, being in the range of 3- 4 cm. Thus, if the 3-4 cm of the thread closest to the IUS have a different colour than the rest of the thread, the coloured part being visible would indicate that the IUS is still inside the uterus but too low.

According to another embodiment, the marking is carried out using laser engraving, and the marking is a scale. In this embodiment, one, two, three, four, five, six, seven, eight, nine, ten or more markings, typically lines that run across the width of the thread, are engraved at certain intervals. Most preferably, the markings are engraved at regular intervals. For example, each marking could be at 1 cm form the previous and subsequent marking. It is also possible to combine the laser marking using a colour additive and laser engraving. In this case, the thread would have both at least one portion of a different colour and a scale engraved on the thread. For example, the portion of different colour could be located close to the IUS, so that even during use, it would be possible to see that the IUS is no longer in its correct position.

The laser used in the present description can be for example a fibre, YAG, or vanadate lasers operating at a wavelength of 1060 to 1070 nm (near infrared spectrum). One example is a Nd:YAG laser operating at 1064 nm. One possible laser machine is Trumpf TruMark 5000. The laser is selected according to the materials used.

The material of the removal thread is selected suitable for use, i.e. able to withstand prolonged (several years) contact with body, biocompatible and sufficiently strong to allow the removal of the IUS. Some possible materials are high-density polyethylene (PE-HD), polypropylene (PP), polyamide (PA), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), thermoplastic polyurethane (TPU) or a thermoplastic elastomer (TPE).

The present disclosure further relates to use of laser marking for marking a removal thread of an intrauterine system. The laser marking is used as explained above, i.e. for example laser engraving or a combined use of an additive capable of changing colour when subjected to laser light. The embodiments above and below thus apply mutatis mutandis to the use.

The present disclosure still further relates to an intrauterine system comprising a removal thread, wherein the removal thread comprises at least one visual marking to indicate insertion depth of the intrauterine system. The variants and embodiments disclosed above in connection with the method apply mutatis mutandis to the IUS. The visual marking in this context means a marking that is easily seen with the eyes of the health care professional, i.e. not requiring use of a magnifying glass or a light different from visible light.

According to an embodiment, the removal thread has a first portion having a first colour and a second portion having a second colour different from the first colour. This is achieved for example by selective application of laser light, as indicated above. It could also be achieved by any other manner, such as by use of a thread with alternating colours of material, i.e. thread that is manufactured as striped. The removal thread may also have portions of more than two different colours, such as three or four different colours. Most typically, the thread will have a first portion or a set of first portions having a first colour and a second portion or a set of second portions having a second colour, where either the first or the second colour may be the colour of the thread as manufactured. Typically, this colour is the colour achieved without any dye.

Thus, it is possible that the removal thread has a first number of first portions having a first colour and a second number of second portions having a second colour different from the first colour. In this embodiment, the first portions and the second portions preferably alternate along the length of the removal thread. The removal thread is thus striped, and the striped preferably all have the same length to create a visual marking that is easy to understand.

According to yet another embodiment, the removal thread may have other visual markings than those made by laser marking or etching, such as regularly spaced apart knots or beads. It is also possible to make the visual marking for a removal thread in two parts, by welding the two parts together at regular intervals. According to yet another embodiment, the removal thread has a scale along its length. This scale can be manufactured for example by laser engraving, or by another engraving method. It is of course important that the tensile strength of the removal thread is not impaired by the marking.

When designing and calculating the appropriate scaling, one needs to take into account the length of the IUS once it is inserted to the uterus, as this length is to be deducted from the sound measurement result (depth of the uterus plus length of the cervical canal). In one example, the length of the IUS is 3 cm and the length of the removal thread is 10 cm (before insertion and cutting). Thus, for example, if the sound measure indicates that the combined depth of the uterus and the length of the cervical canal is 4 cm, the length of thread after insertion and cutting of the thread will be 3-4 cm. Thus, the cut-off part of the thread has a length of 6-7 cm. In case the sound measurement results in a length of 6 cm, the thread length after cutting will be 5-6 cm and the cut off part of the thread a length of 4-5 cm. For a measurement result of 8 or 10 cm, the thread length after cutting will be 7-8 or 9-10 cm, respectively, and the cut-off part of the thread a length of 2-3 cm or 0-1 cm, respectively.

Another embodiment would be addition of a scale sticker or a printed scale to the primary package. In this embodiment, once the IUS is inserted and the removal threads cut, the part of the removal threads that is cut off is measured with the help of the scale sticker. This measurement is then compared to the earlier sound measurement. This embodiment if functional when the thread length remains constant for a given product. The scale sticker or printed scale may comprise firstly a scale, for example from 0-30 cm or 0-25 cm, each cm and mm being indicated on the scale. Additionally, the scale may comprise an area of a colour (such as green) different from the rest of the scale, at a given position. Still further, the scale sticker may comprise parallel lines at various positions, indicating different depths of the uterus. The measurement is carried out for example by placing the first ends of the removal threads on the number corresponding to the sound measurement, i.e. the depth of the uterus. Thereafter, the threads are pulled tight against the scale. The area of different colour is positioned such that when the second ends of the removal threads arrive at this area, the IUS is correctly positioned inside the uterus.

The advantage of this method is that it can be used even in conditions where no ultrasound or similar methods are available. Also, if the healthcare professional does not cut the threads at the correct position, the scale does not give correct information.

Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates an IUS 3 after insertion into a uterus 1. The removal threads 4 of the IUS pass through the cervical canal 2. The lines 5 show the combined length of the depth of the uterus and the length of the cervical canal, i.e. the length measured by the sound prior to insertion of the IUS. The lines 6 show the length of the removal threads that will remain outside the cervical canal, and point 7 is the point where the threads are cut.

Figure 2 shows a marked removal thread according to an embodiment. In this embodiment, the removal thread 8 has portions of different colours, namely portions 9 of a first colour and portions 10 of a second colour, and these portions are alternating, forming the visual markings. The scale 11 illustrates the length of the portions.

Figure 3 shows a marked removal thread according to another embodiment. In this embodiment, the thread 12 has engravings 13 (i.e. visual markings) at regular intervals. Figure 4 shows a marked removal thread according to a further embodiment, in which the thread 14 has engravings 15 (i.e. visual markings) of different thickness at regular intervals. Figure 5 schematically shows an IUS 3 with two removal threads 16. The ends of the removal threads that are attached to the IUS are coloured (portions 17, i.e. visual markings), giving a visual warning to the health care professional, that the IUS is too low in the uterus.

Figure 6 illustrates a scale sticker according to yet another embodiment The scale sticker 19 has a scale 21 and an area 22 of a colour different from the rest of the scale. The scale sticker also has parallel lines 20 at various positions, indicating different depths of the uterus, as indicated by the sound 18 prior to insertion of the IUS.

When the sound measure indicated 7 cm, the first ends of the cut-off removal threads are placed on the corresponding line 20'. If the second ends of the threads, once straightened, arrives and ends within the area 22, as shown by the line 23, the IUS is in correct position. It the second ends arrive and end as indicated by line 24, the IUS is too high in the uterus. If the second ends arrive and end as indicated by line 25, the IUS is too low in the uterus. The correct position of the IUS in the two latter cases should then be checked using ultrasound measurement or similar.

Claims

1. A method for marking a removal thread (4, 8, 12, 14, 16) of an intrauterine system (3), the removal thread having a length L, the method comprising using laser marking. 2. The method according to claim 1, wherein the removal thread (4, 8,

12, 14, 16) of the intrauterine system (3) comprises an additive capable of changing colour when subjected to a laser light, and the laser light is applied on a selected part (9, 17) of the length L of the removal thread.

3. The method according to claim 2, wherein the laser light is applied on a number of selected parts (9) of the removal thread, selected parts and unselected parts alternating along the length L of the removal thread (4, 8, 12, 14, 16).

4. The method according to claim 1, wherein the marking is carried out using laser engraving, and the marking is a scale (13, 15).

5. The method according to claim 2 or 3, wherein an additional marking is carried out using laser engraving, and the additional marking (13, 15) is a scale.

6. Use of laser marking for marking a removal thread (4, 8, 12, 14, 16) of an intrauterine system (3).

7. An intrauterine system (3) comprising a removal thread (4, 8, 12, 14,

16), wherein the removal thread comprises at least one visual marking (9, 10, 13, 15, 17) to indicate insertion depth of the intrauterine system.

8. The intrauterine system (3) according to claim 7, wherein the removal thread (4, 8, 12, 14, 16) has a first portion (9, 17) having a first colour and a second portion (10) having a second colour different from the first colour.

9. The intrauterine system (3) according to claim 8, wherein the removal thread (4, 8, 12, 14, 16) has a first number of first portions (9) having a first colour and a second number of second portions (10) having a second colour different from the first colour, the first portions and the second portions alternating along the length of the removal thread.

10. The intrauterine system (3) according to any of the claims 7-9, wherein the removal thread (4, 8, 12, 14, 16) has a scale (13, 15) along its length.

11. The intrauterine system (3) according to any of the claims 7-10, wherein the visual marking (9, 13, 15, 17) has been achieved by welding two parts of the removal thread (4, 8, 12, 14, 16) together.