DE29919662U1 - Introducer for the insertion of an intrauterine contraceptive device - Google Patents

Description

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Dr. med Siegfried Riek
Konrad-Witz-Strasse 11
78628 Rottweil
Germany

Introducer for the insertion of an intrauterine contraceptive device. 15

For the insertion of progestogen-containing spirals (IUDs), an insertion device for one-handed insertion of this intrauterine device is known (Mirena, registered trademark). The development according to the invention relates to a modification of the known device in order to enable simpler and safer operation. The following problem arises when using the inserter for the Mirena progestogen spiral offered by Schering. In order to enable unhindered unfolding of the IUD arms, it is necessary that there is a distance A between the cranial wall of the uterine cavity and the distal end of the insertion device, or the IUD arms that have not yet unfolded, which corresponds at least to the length of one spiral arm. In order to be able to maintain this distance, it is therefore necessary that after setting the

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Probe length with the slider the IUD introducer device is inserted far enough into the uterine cavity that a distance A remains between the slider for adjusting the probe length and the external cervix. The numbers printed on the insertion tube in front of the slider for adjusting the probe length are hidden by the slider and can only be inadequately seen in the crucial phase of clinical use. Estimating the distance between the cervix and the slider without seeing the numbers on the scale on the insertion tube is also difficult, since viewing at just a slightly different angle to the long axis of the device results in the distance being assessed being shortened in perspective. Furthermore, the insertion device is designed in such a way that the insertion tube is pushed back against the plunger that is firmly connected to the handle via a sliding element that is slidably mounted in the handle in order to release the IUD. The problem is that if the cervical canal is narrow, the friction force between the insertion tube and the cervical canal can be so great that the insertion tube is not pushed proximally with the plunger fixed in the longitudinal axis as intended when handled correctly, but the handle with the plunger is pushed distally with the insertion tube fixed in the longitudinal axis. The problem is therefore that the friction force required to move the

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The force required to insert the insertion tube into the cervix can be greater than the frictional force required to move the handle with the plunger tube against the insertion tube. This fundamental and design-related problem can lead to the dreaded complication of perforation of the uterine wall with the IUD, because in this case the IUD is pressed against the cranial wall of the uterus and can be pushed against the wall of the uterus along the distance corresponding to the spiral shaft and the distance that the sliding element in the handle of the insertion device can travel. This can result in perforation of the uterine wall. The necessary fixation of the insertion device in the longitudinal axis during insertion is practically impossible with a one-handed approach, because relative movements can occur between pushing the handle forwards distally and pushing the sliding element back proximally, depending on the inter-individually varying frictional force between the cervical canal and the insertion tube. As described above, the insertion tube cannot be pushed back proximally due to the doctor's viewing angle deviating only slightly from the longitudinal axis of the insertion device. This cannot be done reliably based on the change in length of the perspectively shortened distance that the distal edge of the slider should move back from the proximal edge of the cervix. Relative movements such as

Advancement of the plunger with the handle in a distal direction and/or only partial retraction of the insertion tube with the sliding element in the handle in a proximal direction are probable.
Troubleshooting :

In order to make this device safe and simple for clinical use, a change in the scale 8 on the insertion tube 4 or a corresponding change in the scale on an auxiliary medium that is used for adjustment or a change in the shape of the slider 5 should ensure that after the probe length has been adjusted and the insertion device has been correctly inserted with the slider 5 resting on the cervix, a distance A still remains between the distal edge of the insertion device and the cranial edge of the uterine cavity. This distance should correspond to the length of a spiral arm 7.7'. Thus, with a corresponding change in the scale for adjusting the probe length, the doctor sets the probe length plus the distance A. Alternatively, the slider could extend so far distally from the proximal edge, which is set to the probe length, that after inserting the insertion device and when the slider 5 rests on the cervix, a distance A remains between the distal edge of the insertion device and the cranial edge of the uterine cavity. Furthermore, the device can be used in an inverted manner, since now the

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The insertion tube 4 can be pushed distally in a clearly defined manner along its longitudinal axis until it reaches the cervix, and this position can be maintained throughout the entire insertion process. The plunger tube 2 can now be pushed proximally by pushing the handle 1 distally with the thumb while simultaneously holding the sliding element 3 between your index and middle finger. This is done with a so-called light hand and using a movement pattern that is familiar to a doctor (as with an injection), since there is only the friction force between the easily movable plunger tube 2 and the insertion tube 4, so that the resistance of the IUD can be felt when it reaches the uterine wall. This palpable resistance allows feedback which signals that the IUD is now correctly positioned.

Figure 1 shows the correctly inserted introducer 9. The slider 5 for adjusting the probe length rests with its distal surface against the cervix. The distance A remains between the distal end of the introducer and the cranial wall of the uterine cavity.

Figure 2: The IUD is correctly positioned in the uterine cavity at the end of the insertion procedure. The handle 1 has been pushed distally until the sliding element 3 has reached the distal limit in the handle and can therefore not be pushed any further distally.
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riup4 List of reference symbols:

l=handle

2=Stamp tube

3=Sliding element
4=Introduction pipe

5=Slider (for adjusting the probe length) 6=IUP

7.7'=Spiral arms

8=Scale for adjusting the probe length 9=Introduction device

Claims (3)

1. Introduction device for inserting an intrauterine device with a handle which is connected to the hollow plunger tube and a sliding element which is displaceably mounted in the handle and is connected to the introduction tube with a device such as a modified scale for adjusting the probe length or a sliding element with a modified shape, with which it is achieved that after the probe length has been adjusted and the slider has been inserted as far as the cervix, a distance A exists between the cranial uterine wall and the distal end of the introduction device, whereby the slider for adjusting the probe length can only be moved on the introduction tube against a high friction force, so that it does not move when the handle is pressed distally with the slider resting on the cervix. 2. An introduction device according to claim 1 with an introduction tube with a modified scale, or modified scale of an auxiliary medium for adjusting the probe length, so that a distance A adapted to the IUD remains between the cranial uterine wall and the distal end of the fully inserted introduction device. 3. Introduction device with a specially designed slider, whereby the length of the introduction tube located in front of the distal edge of the slider corresponds, after adjustment, to the probe length minus a distance A.