GB2503059A

GB2503059A - Tool for removing implant

Info

Publication number: GB2503059A
Application number: GB201223487A
Authority: GB
Inventors: Vaniya Nanu-Kandiyil
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-06-12
Filing date: 2012-12-28
Publication date: 2013-12-18
Also published as: GB201223487D0; GB201210307D0

Abstract

A tool for removing bodily implants e.g. contraceptive implant, the tool 30 comprising a handle 37 at the first proximal end and an insertion element 34 terminating with a point at a distal end 35 for insertion into an implant, wherein from the distal end 35 of the insertion point towards the handle, an external thread 36 is defined about a rotational axis, operable to define and engage with a helical groove within a body of an implant, the handle 37 having a generally circularly cylindrical body about said axis of rotation. The tool 30 may be inserted into the end of the implant and then withdraw pulling the implant out of the skin.

Description

An Imrlant Tool

Field of the Invention

The present invention relates to implants as used in animal and human bodies and to a tool therefore. In particular, the present invention relates to an improved device for removal of implants and to a method for the removal of the same.

Background to the Invention

The use of implants is presently being adopted for the slow release of hormones and other types of drugs and medication. Implants typically comprise little strips of plastics material which contain a drug that is released gradually over time. Some of the more commonly used implants are contraceptive implants which deliver a hormone that, inter alia, prevents females from ovulating and provides a number of other secondary reactions so that pregnancy is most unlikely.

Merck pharmaceuticals have produced implantable contraceptives under the trade manes Nexplanon and Implanon, which consist of a single rod made of a plastics material that is similar to a matchstick in size being 4cm long and 2mm in diameter, comprising a core with an outer plastics coating, such as ethylene vinylacetate copolymer as used by Merck with their implants. Such hormonal implants are inserted under the skin of a patient, typically on the inside of an upper arm.

The insertion of hormonal implants is considered a minor procedure; the implant is typically inserted under the skin of an inside face of an upper arm of a patient. This procedure is typically performed at a doctor's surgery or at an outpatients department of a hospital and can be performed in as little as about 5 minutes, but may take longer, for example, when scar tissue is present or the patient is obese. The surgery is done with local anaesthesia placed just around the area of the upper arm, where the implants will be inserted. Referring to Figure 1, the implant usually come with an applicator 10 consisting of a stainless steel needle or cannula 16, which is fitted to an acrylonitrile-butadiene-styrene polymer (ABS) applicator 14; the implant 22 is inserted upon retraction of the applicator whilst pushing with piston arrangement 12. Figure 2 shows the relative size of an implant 22 with respect to a hand 24. Merck has marketed a new implant inserting tool which is likely to avoid inadvertent deeper insertion. The implants are usually inserted within the first seven days of a menstrual cycle or whilst the patient is still taking oral contraceptives. The correct insertion site is subdermal in the groove between the biceps and triceps, approximately six cm to eight cm above the medial humeral condyle. Typically the applicator device is employed with a large cannula to insert the device once a local anaesthetic has been provided in the site of interest. It is noted that there are many complicating factors; a nervous patient may move suddenly -even if anaesthetised locally; an overweight person may have folds of skin; there may be scar tissue. Once inserted, it is good practice to palpate to confirm placement of the implant. An implant may be impalpable because of failed insertion technique resulting in non-insertion, deep insertion, or migration, which is very rare.

Present advice is to have these implants removed after three years, to ensure that the effect of the implant can be assured. Implant is the most effective hormonal contraceptive available today, preventing 999 in 1000 pregnancies over its recommended period. Furthermore, in the case of contraceptive implants, women may want to remove the implant if they wish to become pregnant. Another reason for removal of an implant may be the presence of side-effects, such as irregular bleeding, or the issue of a contra-indication arising from a disease, such as cancer, especially breast cancer, ovarian cancer or cancer of the uterus.

The type of contraceptive implant that is currently used in the UK (Nexplanon) should, in theory at least, be impossible to lose -because it contains a small amount of a dye -barium sulphate -that is visible on X-rays. In practice, when an implant appears to be missing from its expected position, it often turns out to be only a few centimetres away.

Removal of an implant can be performed by injecting a small amount of local anaesthetic into the arm of the implantee, and then making a small cut with a scalpel, through which the implant is removed, by way of mosquito forceps in the event that the implant is palpable i.e. can be determined in position by gentle manipulation of the area where the implant has been placed. However, there are numerous cases where the implants could not easily be removed due to a number of reasons, typically being one of: fibrosis around implant, migration of the implant, obesity of the implantee, scar tissue in the region of implant or incorrect insertion of the implant, whereby the implant cannot easily be located.

Patients with a non-palpable insert can be treated in a number of ways: Following a clinical assessment and examination of the arm where an implant has been inserted, an ultrasound examination can be carried out to identify and locate the implant. However, the removal of non-palpable rods can be difficult because the implant is not always visible with ultrasound. X-ray, ultrasound, computed tomography, and magnetic resonance imaging (MRI) have also been utilised as methods to localize implants. visualization by MRI is not always readily available, relatively complicated and expensive. Visualization by ultrasonography is also not always readily available and may be difficult in the hands of inexperienced physicians especially in the event the implant was inserted incorrectly. Nexplanon is radio-opaque and can be located and identified using X-ray techniques.

In J Fam Plann Reprod Halth Care 2012; 38:207-208, the inventor describes a method for removal of implants by stabilising the implant with a needle. However, this method is an improvement upon the use of needle and mosquito forceps. Curved mosquito forceps are recommended to grasp the implant after the incision is made; whilst they typically have anti-slip grip sections which enable the implant to be secured easily, this contributes to an increased likelihood of tissue damage and swelling.

Object of the Invention The present invention seeks to provide a solution to the above problems.

The present invention seeks to provide an improved tool and method of use to enable removal of an implant, whereby implants can be securely, safely and simply be removed.

Statement of the Invention

In accordance with a first aspect of the invention, there is provided a tool for stabilising and removing implants, the tool comprising a handle at a first, proximal end and an insertion element terminating with a point at a distal end for insertion into an implant, wherein from the distal end of the insertion point towards the handle, an external thread is defined about a rotational axis, operable to define and engage with a helical groove within a body of an implant, the handle having a generally circularly cylindrical body about said axis of rotation. In use, an end of an implant can be presented to the insertion point of the tool, the tool rotated and pushed into the implant, conveniently into the core, from an end of the implant, although it is also possible to approach and pierce the outer cylindrical wall from an oblique angle, whereby to secure implant with respect to the device of the present invention.

Conveniently, the distal end terminates in a needle like element, the external thread extending at a lead distance from the termination part, to assist in initial penetration of the tool; in one sense it can be described as a needle screw.

The thread can be of various characteristics; the thread can be a twin thread; the thread can be a worm thread. Conveniently, the diameter of the helical thread increases, whereby the tool increases its purchase upon an core of the implant -it is known that the polymers used to protect the core are elastic in nature and this can increase the grip between the tool and an inside portion of the implant to at least an inside art and an inside surface of the wall of the implant.

In accordance with another aspect of the invention, there is provided a method of removing an implant from within a human or animal body, the method comprising the steps of identifying the implant; determining an end portion of the implant and supporting said end portion of the implant; inserting the insertion tool in accordance with the first aspect of the invention into the body of the implant, as defined between a first outside surface and a second outside surface of the implant; urging and rotating the insertion tool into the implant such that the external screw thread of the insertion tool defines and engages with a helical groove within the body of the implant; withdrawing the implant from a position of implantation. The process of inserting the device and making an incision may be reversed.

Brief description of the Figures

Some preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, of which: Figure 1 shows an applicator for implants(older one) Figure 2 shows an implant; Figure 3 shows a first embodiment of the invention; Figure 4 shows a second embodiment of the invention; Figure 3a and 4a show cross-sections through the shafts of the first and second embodiments of the invention; Figure 5 shows an area of skin in the region of an implant; Figure 5a shows the present invention as it approaches an implant prior to insertion; Figure Sb shows how the tool of the present invention can screw-fixedly attach itself to an implant; and Figure 6 shows an area of skin in the region of an implant as an incision is made.

Detailed Description of the Preferred Embodiments

There will now be described, by way of example only, the best mode contemplated by the inventor for carrying out the present invention. In the following description, numerous specific details are set out in order to provide a complete understanding to the present invention. It will be apparent to those skilled in the art, that the present invention may be put into practice with variations of the specific.

With reference to Figure 3, there is shown a first embodiment of the present invention. The insertion tool comprises an insertion member 32 connected to a handle 32. The insertion member 32 includes a shank 34 which in this case is substantially cylindrical from the handle until it approaches the distal end 35 when it reduces to a point. A helical thread is 36 arranged about the shank and starts a little distance from the distal end, so that the point can cleanly enter the soft core of an implant (best seen with reference to Figures Sa & Sb, below). Figure 3a shows a radial cross-section along the shank, in the region of the thread. Reference numeral 37 indicates a surface of the handle, which conveniently defines a pattern to assist grip. The tool is conveniently made of a suitable stainless steel, although a cheaper plastics moulding could also be provided. The insertion shank may be formed of stainless steel and the handle from plastics to provide a more acceptable lower cost device.

Figure 4 shows a first alternative, where the screw thread is an internal worm thread 44, which can be less damaging to the polymer coating of the typical implant as an external screw thread could possibly cut through if not properly handled. The shank 42 however increases in diameter as it approaches the handle. Figure 4a shows a radial cross-section along the shank.

Figure 5 shows an area of skin 50 in the region of an implant. The implant is indicated in dotted lines 22. The implant rod must then be positively located, conveniently by palpation; logically the implant will not have moved, but the presence of scar tissue, weight gain and weight loss can each contribute to difficulties in locating the implant. Palpation involves the manipulation of the implant whereby it can be identified; otherwise imaging techniques using ultrasound, radioactive markers or MRI techniques can be implemented, each of which can delay the procedure from being a couple of minutes to tens of minutes. Once located, a local anaesthetic is typically injected under or beneath the rod whilst taking care neither to displace the implant rod nor obscure the implant rod. The area of skin where the implant is located is cleansed and given an antiseptic wash in area 54. The end of the implant is grasped firmly with a toothed dissecting forceps.

S

With reference to Figures 5a and Sb, the removal device of the present invention is then utilised such that the sharp distal end 35 is moved in a direction indicated by dashed line 80 by an operator towards the axial face 23 of implant 22, to engage the core and progress insertion of the device, with rotation of the device whereby the implant is secured to the device.

Conveniently, the needlepoint enters the end face of the elongate implant.

However, it is also possible to enter the elongate sidewall of the implant at an oblique angle and to subsequently penetrate the core and thereby secure the device with respect to the implant. Once the implant is stabilised with the tool a deliberate incision through the dermis with a number 15 scalpel blade which should be 45 degree slanting to go just under the implant. Gently pulling the tool, fascias can be separated and implant can be pulled out with the tool. Once the implant has been removed, then the wound can be dressed.

The needle screw can also be employed after an incision has been made in the skin whereby to make the implant accessible through the incision and enable stabilisation with some dissecting forceps prior to insertion of the needle screw. Encapsulated implants may require further dissection, where sharp or blunt dissection of the fibrous capsule is required prior to removal of the rod. Specifically and with reference to Figure 6, an incision 62 is made in the skin with a scalpel 64 -a number 15 scalpel has been found to be appropriate in most circumstances; the incision is then subsequently inspected to locate the implant 22.

Claims

Claims 1. A tool for removing bodily implants, the tool comprising a handle at a first, proximal end and an insertion element terminating with a point at a distal end for insertion into an implant, wherein from the distal end of the insertion point towards the handle, an external thread is defined about a rotational axis, operable to define and engage with a helical groove within a body of an implant, the handle having a generally circularly cylindrical body about said axis of rotation.
2. A tool according to claim 1, wherein the distal end terminates in a needle like element, the external thread extending at a lead distance from the termination part.
3. A tool according to claim 1 or 2, wherein the external thread is a twin thread.
4. A tool according to claim 1, wherein the external thread is tapered.
5. A tool according to any one of claims 1 -3, wherein the or each thread has a pitch, which pitch is greater than the diameter of the shank.
6. A tool according to any one of claims 1 -3, wherein the or each thread is a worm thread.
7. A tool according to claim 6, wherein the shank is tapered.
8. A tool according to any one of claims 1 -3, wherein or each thread is notched at its distal end.
9. A method of removing an implant from within a human or animal body, the method comprising the steps of: i) identifying the implant; ii) determining an end portion of the implant and supporting said end portion of the implant; iii) inserting the tool in accordance with any one of claims 1 -8 into the body of the implant, as defined between a first outside surface and a second outside surface of the implant; iv) urging and rotating the tool into the implant such that the external screw thread of the tool defines and engages with a helical groove within the body of the implant; and, v) withdrawing the implant from a position of implantation.
10. A method of removing an implant from within a human or animal body according to claim 9, the method further comprising the step of making an incision in the skin prior to insertion of the needle scew-insertion tool.
11. A method of removing an implant from within a human or animal body, according to claim 9, the method further comprising the step of making an incision in the skin after insertion of the insertion tool.
12. An insertion tool substantially as described herein with reference to any one or more of the Figures as shown in the drawing sheets.
13. A method of removing an implant from within a human or animal body substantially as described herein with reference to any one or more of the Figures as shown in the drawing sheets.
14. A tool, said tool comprising a handle at a first, proximal end and an insertion element terminating with a point at a distal end, wherein from the distal end of the insertion point towards the handle, an external thread is defined about a rotational axis, the handle having a generally circularly cylindrical body about said axis of rotation, when used in the removal of an implant from an animal, the method comprising the steps of: i) identifying the implant; ii) determining an end portion of the implant and supporting said end portion of the implant; iii) inserting the tool in accordance with any one of claims 1 -8 into the body of the implant, as defined between a first outside surface and a second outside surface of the implant; iv) urging and rotating the tool into the implant such that the external screw thread of the tool defines and engages with a helical groove within the body of the implant; and, v) withdrawing the implant from a position of implantation.