Medical devices

Abstract

To provide a medical device that can effectively dilate the urethra of a patient while further reducing the burden on the patient. [Solution] The medical device 100 includes one or more first magnets 110 that are implanted in the prostate P located around the urethra U to be dilated, and one or more second magnets 120 that can be placed outside the body O of the subject in which the first magnets are implanted, and generate a traction force that dilates the urethra in relation to the first magnets.

Description

Technical Field

[0001] The present invention relates to a medical device used for urethral dilation.

Background Art

[0002] Benign prostatic hyperplasia is a disease caused by the prostate gland enlarging due to factors such as aging and hormonal imbalance, which compresses the urethra and causes disorders related to urination and various complications (such as urinary tract infection, bladder stones, renal dysfunction, etc.).

[0003] Conventionally, as treatment methods for benign prostatic hyperplasia, drug treatment and TUR-P (Transurethral resection of Prostate) are known.

[0004] With drug treatment, it is possible to improve and relieve symptoms, but depending on the degree of progression of benign prostatic hyperplasia, sufficient effects may not be expected in some cases.

[0005] <​​​​​​​​The medical device described in Patent Document 1 comprises a shaft assembly that can be inserted into the urethra, a needle delivered into the urethra via the shaft assembly, and an anchor assembly (wire-like structure) that is positioned to bridge the gap between the urethra and the outer portion of the prostate (outer surface of the prostatic capsule) and generates tension to widen the urethra.

[0008] In the treatment method using the medical device described in Patent Document 1, a shaft assembly is inserted into the urethra through the external urethral orifice, a needle is delivered into the urethra through the lumen of the shaft assembly, and the needle is punctured from inside the urethra toward the outer portion of the prostate. Then, an anchor assembly is placed between the urethra and the outer portion of the prostate through the perforation formed by the needle.

[0009] According to the above procedure, while the anchor assembly is implanted in the patient's body, the tension of the anchor assembly can maintain a physically expanded state of the patient's urethra. Therefore, compared to drug therapy, it is possible to effectively improve and alleviate the condition of urethral compression caused by an enlarged prostate. Furthermore, according to the above procedure, the amount of bleeding during the procedure can be reduced compared to TUR-P, which involves surgical removal of prostate tissue, thus reducing the burden on the patient. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] WO2010 / 014821 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] However, in the treatment method using the medical device described in Patent Document 1, as mentioned above, a shaft assembly is inserted into the urethra via a transurethral approach, and a perforation is then created using a needle to connect the inside of the urethra to the outer part of the prostate. Therefore, general anesthesia is required for the patient when performing the procedure. Furthermore, since the above treatment method creates a perforation connecting the inside of the urethra to the outside of the prostate, there is room for further improvement in terms of invasiveness.

[0012] The present invention has been made in response to the above-mentioned problems, and aims to provide a medical device that can effectively dilate the urethra of a subject and further reduce the burden on the subject. [Means for solving the problem]

[0013] The present invention can be achieved by any one of the following means (1) to (7).

[0014] (1) A medical device used to dilate the urethra, One or more first magnets are implanted in the prostate gland, located around the urethra to be dilated, A medical device comprising one or more second magnets that can be positioned outside the body of a subject to which the first magnet is implanted, and which generate a traction force between themselves and the first magnet to expand the urethra.

[0015] (2) The medical device according to (1), comprising two or more of the first magnets.

[0016] (3) The medical device according to (2), wherein each of the two or more first magnets is arranged at a predetermined distance from each other at least in the transverse direction in the cross-section of the prostate.

[0017] (4) Having three or more of the aforementioned first magnets, A medical device according to (2) or (3) that generates the aforementioned tensile force of 2N or more.

[0018] (5) The medical device according to any one of (1) to (4), which is used for a patient suffering from benign prostatic hyperplasia in which the Young's modulus of the biological tissue at the implantation position of the first magnet is 30 kPa or more and 46 kPa or less.

[0019] (6) The medical device according to any one of (1) to (5), wherein the first magnet is a rod-shaped magnet having a longitudinal direction extending along the implantation direction into the prostate.

[0020] (7) The medical device according to (6), wherein the first magnet is a rod-shaped magnet having a magnetization direction in the short-hand direction.

Advantages of the Invention

[0021] According to the medical device of the present invention, a pulling force for expanding the urethra can be generated in the prostate by the magnetic force between the first magnet implanted in the prostate and the second magnet arranged outside the living body (patient) of the subject. Thereby, the urethra compressed by the enlarged prostate can be expanded, and it becomes possible to improve and relieve urinary disorders and the like associated with benign prostatic hyperplasia. Further, according to the medical device of the present invention, since the first magnet can be implanted in the prostate by a transperineal approach, it is not necessary to subject the subject to general anesthesia when performing the treatment. In addition, in a treatment using a medical device in which a member such as an anchor is placed in the urethra by a transurethral approach, it is necessary to form a perforation connecting the urethra and the outside of the prostate, but when the medical device of the present invention is used, such a treatment becomes unnecessary. Therefore, according to the present invention, it is possible to provide a medical device that can effectively expand the urethra of the subject and further reduce the burden on the subject.

Brief Description of the Drawings

[0022] [Figure 1] [[ID=​This is a longitudinal cross-sectional view of the first magnet according to the embodiment, taken along its longitudinal direction. [Figure 3] This is a cross-sectional view of the first magnet along the line 3A-3A shown in Figure 2. [Figure 4] This is a schematic diagram illustrating a method for implanting (implanting) a medical device according to an embodiment. [Figure 5] This is a schematic diagram illustrating a method for implanting (implanting) a medical device according to an embodiment. [Figure 6] Figure 5 shows a schematic cross-sectional view along the line 6A-6A. [Figure 7] This is a diagram illustrating an example (simulation of a treatment method using a medical device). [Figure 8] This is a diagram illustrating an example (simulation of a treatment method using a medical device). [Figure 9] This figure shows the results of an example (simulation of a treatment method using a medical device). [Modes for carrying out the invention]

[0023] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The embodiments shown herein are illustrative examples to embody the technical idea of ​​the present invention and do not limit the present invention. Furthermore, all other implementable forms, examples, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included in the scope and spirit of the present invention, as well as in the claims and their equivalents.

[0024] The drawings attached to this specification may be schematically represented with changes to scale, aspect ratio, shape, etc., from the actual object for the sake of illustration and ease of understanding, but they are merely examples and do not limit the interpretation of the present invention.

[0025] In the following explanations, when ordinal numbers such as "1st" and "2nd" are used, they are for convenience only and do not prescribe any particular order unless otherwise specified.

[0026] The arrows X1-X2 in the figure indicate the longitudinal direction of the first magnet 110, the arrows Z1-Z2 indicate the transverse direction perpendicular to the longitudinal direction, and the arrows Y1-Y2 indicate the depth direction perpendicular to both the longitudinal and transverse directions. Figure 2 shows a longitudinal section of the first magnet 110 along the longitudinal direction, and Figure 3 shows a cross-sectional view of the first magnet 110 along the transverse direction.

[0027] The medical device 100 according to this embodiment will be described below.

[0028] As shown in Figures 1 and 6, the medical device 100 includes one or more first magnets 110 that are implanted in the prostate P located around the urethra U to be dilated, and one or more second magnets 120 that can be placed outside the body O of the subject in which the first magnets 110 are implanted, and generate a traction force between themselves and the first magnets 110 to dilate the urethra U.

[0029] In this embodiment, an example is shown in which the medical device 100 comprises three first magnets 110A, 110B, and 110C. In the description of this specification, when referring to each of the first magnets 110A, 110B, and 110C collectively, they will simply be referred to as "first magnet 110".

[0030] The subjects to whom the medical device 100 is applied are, for example, male patients suffering from benign prostatic hyperplasia. The target of dilation (treatment) by the first magnet 110 is at least a portion of the subject's urethra U. Specifically, the target of dilation is any part of the urethral prostatic portion U located within the prostate P in the urethra U, where the lumen has been narrowed due to the enlargement of the prostate P.

[0031] In a procedure using the medical device 100, the operator (for example, a medical professional performing the procedure) places the second magnet 120 outside the body O while the first magnet 110 is implanted (placed) inside the prostate P, as shown in Figures 1 and 6.

[0032] By arranging the first magnet 110 and the second magnet 120 as described above, the operator can attract the first magnet 110 towards the second magnet 120 due to the magnetic force between them. As the first magnet 110, implanted in the prostate P, is attracted towards the second magnet 120 located outside the body O, and moves closer to the second magnet 120, the prostate tissue (radiotype) near the implantation site of the first magnet 110 is pulled towards the second magnet 120 as the first magnet 110 moves. When the prostate tissue is pulled towards the second magnet 120, as shown in Figure 6, the urethra U located near the implantation site of the first magnet 110 expands towards the outside body O where the second magnet 120 is located, relieving the compression of the urethra U by the enlarged prostate P. In each figure, the tensile force generated by the first magnet 110 and the second magnet 120 is illustrated by arrow F.

[0033] In Figure 6, the solid line representing the urethra U (prostatic urethra up) illustrates the state before dilation, while the dashed line representing the urethra U illustrates the state after dilation. In the cross-sectional view of Figure 6, the urethra U and prostate P are simplified into circles, etc., but this is for illustrative purposes only, and the actual shape is not limited to this shape.

[0034] As shown in Figures 1 and 6, when the operator places the second magnet 120 on the abdominal side of the subject (upper side in Figure 6) and expands the urethra U toward the abdomen, the first magnet 110 can be placed more abdominally than the urethra U. In other words, the first magnet 110 can be implanted so that the urethra U is not positioned between the first magnet 110 and the second magnet 120. By implanting the first magnet 110 in this way, when the urethra U is expanded by the first magnet 110 and the second magnet 120, the urethra U can be expanded toward the second magnet 120 side (upper side in Figure 6).

[0035] For example, if the first magnet 110 is implanted in the prostate P such that the urethra U is positioned between the first magnet 110 and the second magnet 120, the first magnet 110 will be pulled towards the abdomen when the second magnet 120 is placed on the abdominal side of the external body O. This may cause the urethra U, located between the first magnet 110 and the second magnet 120, to be compressed. Even when the first magnet 110 is positioned in this way, the urethra U can be expanded toward the back by placing the second magnet 120 on the posterior side. However, in order to make the magnetic force between the first magnet 110 and the second magnet 120 work more efficiently, it is preferable to shorten the distance between the prostate P and the external body O, or to consider delivery to the prostate P, as shown in Figures 1 and 6, to implant the first magnet 110 on the abdominal side of the urethra U and place the second magnet 120 on the abdominal side.

[0036] The position in which the first magnet 110 is implanted in the prostate P is not particularly limited, as long as the first magnet 110 implanted in the prostate P and the second magnet 120 placed outside the body O can expand at least a portion of the urethra U.

[0037] As shown in Figures 1 and 6, the medical device 100 can be configured to include two or more first magnets 110. As previously mentioned, this embodiment illustrates a medical device 100 having three first magnets 110A, 110B, and 110C.

[0038] By equipping the medical device 100 with multiple first magnets 110A, 110B, and 110C, it becomes possible to easily adjust the magnetic force between the first magnet 110 and the second magnet 120 (adjusting the traction force to expand the urethra U).

[0039] For example, when using a single first magnet 110 to apply a certain magnitude of magnetic force between the first magnet 110 and the second magnet 120, it is possible to adjust the size, shape, and volume of the first magnet 110. If a larger magnetic force is to be applied between the first magnet 110 and the second magnet 120, the size of the first magnet 110 can be simply increased. However, if the first magnet 110 is made larger, the workload during implantation into the prostate P may increase, or it may cause excessive discomfort or unease in the patient to whom the first magnet 110 is implanted.

[0040] To address the above-mentioned challenges, the medical device 100 according to this embodiment includes a plurality of first magnets 110A, 110B, and 110C, as described above. Therefore, it is possible to miniaturize and reduce the diameter of each of the first magnets 110A, 110B, and 110C while generating a magnetic force equivalent to that of a single first magnet. Furthermore, the medical device 100 can be arranged with a predetermined interval between each of the first magnets 110A, 110B, and 110C in a lateral direction intersecting the extending direction of the urethra U (indicated by the arrows Y1-Y2 in Figure 6). When the first magnets 110A, 110B, and 110C are arranged in this manner, the medical device 100 can generate a magnetic force and traction force substantially equivalent to that of a single first magnet having a cross-sectional area (projected area A shown by the dashed line in Figure 6) corresponding to the distance between the first magnet 110B and the first magnet 110C located at both ends in the lateral direction. Therefore, by equipping the medical device 100 with multiple first magnets 110A, 110B, and 110C, it is possible to generate a predetermined magnitude of magnetic force and traction force, and to reduce the discomfort or unease experienced by the subject to whom the first magnet 110 is implanted.

[0041] In this embodiment, an example is described in which the medical device 100 has three first magnets 110A, 110B, and 110C. However, the number of first magnets 110 in the medical device 100 is not particularly limited, as long as it can generate magnetic force and traction force capable of expanding the urethra to a predetermined size.

[0042] As shown in Figure 6, each of the two or more first magnets 110A, 110B, and 110C can be arranged at a predetermined distance from each other in at least the lateral direction in the cross-section of the prostate P.

[0043] In this embodiment, the medical device 100 comprises three first magnets 110A, 110B, and 110C. When the medical device 100 comprises three first magnets 110A, 110B, and 110C in this manner, for example, as shown in Figure 6, one first magnet 110A can be positioned vertically from the urethra U toward the second magnet 120, and the first magnets 110A and 110B can be positioned with a predetermined lateral spacing between them. By providing lateral spacing between the first magnets 110A, 110B, and 110C in this way, it becomes possible to apply traction force to the prostate P over a relatively wide lateral range. Therefore, the first magnet 110A pulls the prostate P tissue located around the urethra U upward in the vertical direction of the cross-section, while the first magnets 110B and 110C, positioned laterally offset from the first magnet 110A, can pull the prostate P and urethra U upward in the vertical direction or diagonally upward. This makes it possible to efficiently expand the urethra U.

[0044] There are no particular restrictions on the lateral distance (size of the gap) between the first magnets 110A, 110B, and 110C implanted in the prostate P, however, a distance of, for example, 1 mm to 30 mm can be provided between adjacent first magnets 110 in the lateral direction.

[0045] Furthermore, as shown in Figure 6, the first magnets 110A, 110B, and 110C may be positioned with their vertical positions offset from each other in the cross-section of the prostate P. In other words, the central axis c1 of each first magnet 110A, 110B, and 110C does not have to be positioned at the same vertical position (indicated by arrows Z1-Z2) in the cross-section of Figure 6, or it may be positioned at the same vertical position as described above.

[0046] As shown in Figure 2, the first magnet 110 can be made up of a rod-shaped magnet having a longitudinal direction (indicated by arrows X1-X2) that extends along the direction of implantation into the prostate P.

[0047] The "implantation direction to the prostate P" mentioned above refers to the direction from the abdominal side (front side) of the subject's body toward the inside of the body, or from the dorsal side (back side) of the subject's body toward the inside of the body, as shown in Figures 1, 4, and 5.

[0048] As shown in Figure 2, the first magnet 110 comprises one end 111 located on one side in the longitudinal direction, another end 113 located on the opposite end from the one end 111, and an intermediate portion 115 extending between the one end 111 and the other end 113.

[0049] As shown in Figures 2 and 3, the first magnet 110 can be configured to have a cylindrical shape with a substantially identical circular cross-section along its entire longitudinal direction. In this embodiment, all first magnets 110A, 110B, and 110C are configured with the same shape. However, if the medical device 100 includes multiple first magnets 110, the shapes of each first magnet 110 (longitudinal shape and cross-sectional shape) may be the same or different.

[0050] The first magnet 110 has a circular cross-sectional shape, so there are no vertices (corners) when viewed in cross-section. Therefore, it is possible to reduce the discomfort, unease, and pain experienced by the patient when implanting the first magnet 110 in the prostate P or while it is implanted.

[0051] In this embodiment, when using three cylindrical first magnets 110A, 110B, and 110C as the first magnet 110 to be implanted in the prostate P, if a predetermined tensile force (2N or more), as described later, is generated, for example, each part of the first magnet 110 can be configured with the following dimensions.

[0052] The longitudinal dimension (length) L1 of the first magnet 110 can be, for example, 5 mm or more and 40 mm or less. The short-axis dimension (diameter) D of the first magnet 110 can be, for example, 1 mm or more and 5 mm or less.

[0053] Furthermore, the shape of the cross-section of the first magnet 110 is not particularly limited as long as it performs the function of expanding the urethra U. For example, the shape of the cross-section of the first magnet 110 may be a polygon such as a square or rhombus, an ellipse, or other geometric shape. Also, the shape of the cross-section of the first magnet 110 does not have to be the same along the longitudinal direction of the first magnet 110. In other words, the cross-sectional shape of the first magnet 110 may change at any point along its longitudinal direction. For example, the first magnet 110 can be formed in a tapered shape in which the outer diameter gradually increases from one end 111 located on the insertion direction side to the other end 113 located on the opposite side of the insertion direction. When the first magnet 110 is configured in such a shape, it becomes possible to insert (implant) the first magnet 110 into the prostate P more smoothly.

[0054] As shown in Figure 1, the first magnet 110 can be implanted in the prostate P such that its longitudinal direction is aligned with the direction of extension of the urethra U located within the prostate P. By implanting the rod-shaped first magnet 110, which has a longitudinal direction, in the prostate P as described above, it becomes possible to apply a tensile force to expand the urethra U over a predetermined range in the direction of extension of the urethra U (the range in which the longitudinal direction of the first magnet 110 and the direction of extension of the urethra U overlap) when a magnetic force is generated between the first magnet 110 and the second magnet 120. Therefore, it becomes possible to efficiently expand the urethra U over a predetermined range along the direction of extension.

[0055] When implanting two or more rod-shaped first magnets 110A, 110B, and 110C into the prostate P, as in this embodiment, the central axes c1 along the longitudinal direction of each first magnet 110A, 110B, and 110C can be arranged so that they are parallel to each other, as shown in Figure 1. By adjusting the arrangement of each first magnet 110A, 110B, and 110C in this way, it becomes possible to reduce the pain and discomfort felt by the patient when implanting each first magnet 110A, 110B, and 110C into the prostate P. Furthermore, since it becomes possible to generate a uniform tensile force along the longitudinal direction of each first magnet 110A, 110B, and 110C, it becomes possible to appropriately expand a predetermined range along the extending direction of the urethra U.

[0056] In this embodiment, as shown in Figure 6, an example is shown in which multiple first magnets 110 are arranged at different lateral positions on the cross-section of the prostate P. However, in a procedure using the medical device 100, for example, multiple first magnets 110 may be arranged in a line at different positions in the direction of extension of the urethra U.

[0057] The first magnet 110 can be made up of a rod-shaped magnet having a magnetization direction in the shorter direction.

[0058] As described above, the first magnet 110 can be implanted in the prostate P so as to be located between the urethra U and the second magnet 120 located outside the body O in the schematic cross-sectional view shown in Figure 6. When implanting the first magnet 110 in this way, if a magnetic force is applied between the first magnet 110 and the second magnet 120 to expand the urethra U, it is preferable that the first pole 117a located on the outside-of-body O side of the first magnet 110 and the first pole 127a located on the prostate P side of the second magnet 120 are configured as opposite poles. In this embodiment, as shown in Figures 3 and 6, the magnetization direction of the first magnet 110 is set such that it has different first poles 117a and second poles 117b in the short direction of the first magnet 110, with reference to the center position of the cross-section of the first magnet 110 (the position through which the central axis c1 passes).

[0059] As shown in Figure 1, the first pole 117a can be configured to have the same magnetic pole along the entire longitudinal direction of the first magnet 110. By configuring the first magnet 110 in this way, it becomes possible to generate a substantially constant magnetic force and traction force along the longitudinal direction of the first magnet 110. Therefore, it becomes possible to apply a uniform traction force to a predetermined range in the extending direction of the urethra U located in a range that overlaps with the longitudinal direction of the first magnet 110.

[0060] In this embodiment, as shown in Figure 6, the first pole 127a of the second magnet 120 is configured as a north pole, and the second pole 127b is configured as a south pole. Therefore, the first pole 117a of the first magnet 110 is configured as a south pole, and the second pole 117b of the first magnet 110 is configured as a north pole. However, the magnetic poles of each magnet 110 and 120 can be arbitrarily changed as long as a magnetic force can be applied between them.

[0061] The first magnet 110 can be made of a permanent magnet. For example, the first magnet 110 can be made of a neodymium magnet capable of generating a relatively large magnetic force. However, there are no restrictions on the material, type, manufacturing method, etc., of the first magnet 110, as long as it can generate a traction force that expands the urethra U.

[0062] As shown in Figures 1, 5, and 6, the second magnet 120 can be positioned near the prostate P outside the body when performing a procedure using the medical device 100. For example, as shown in Figure 5, the second magnet 120 can be positioned near the inguinal region, located above the position where the first magnet 110 is implanted in the prostate P, along the vertical direction toward the body surface. However, the position in which the second magnet 120 is positioned when performing a procedure using the medical device 100 is not particularly limited, as long as it is possible to expand at least a portion of the urethra U.

[0063] The second magnet 120 can be made of, for example, a permanent magnet or an electromagnet.

[0064] If the second magnet 120 is made of a permanent magnet, the mechanism for generating the traction force including the second magnet 120 can be made of a simple structure. However, if the second magnet 120 is made of a permanent magnet, unlike if the second magnet 120 is made of an electromagnet, it is not possible to adjust the magnitude of the magnetic force of the second magnet 120 by changing the magnitude of the current supplied to the second magnet 120. Therefore, for example, if the magnitude of the traction force is to be adjusted after the first magnet 110 has been implanted in the prostate P, it is necessary to change the second magnet 120 to one with a stronger (or weaker) magnetic force, or to change the arrangement of the second magnet 120 to widen (or narrow) the distance between it and the first magnet 110.

[0065] On the other hand, if the second magnet 120 is made of an electromagnet, the magnitude of the traction force can be easily adjusted by adjusting the magnitude of the current supplied to the second magnet 120. However, if the second magnet 120 is made of an electromagnet, the mechanism for generating the traction force, including the second magnet 120, becomes more complex compared to the case where the second magnet 120 is made of a permanent magnet.

[0066] In the medical device 100, considering the points mentioned above, the second magnet 120 can be made of a permanent magnet if a simple mechanism for generating traction force is desired, or the second magnet 120 can be made of an electromagnet if a mechanism that allows for easy adjustment of the traction force is desired. Thus, the form of each magnet 110 and 120 can be arbitrarily selected considering the product specifications. In this embodiment, as shown in Figures 1 and 6, an example is shown in which the second magnet 120 is made of a permanent magnet.

[0067] Regardless of whether the second magnet 120 is made of a permanent magnet or an electromagnet, the medical device 100 can be equipped with a structure for attaching or fixing the second magnet 120 to the subject's body. For example, the medical device 100 can be equipped with a band-type attachment member that can be wrapped around the abdomen, lower abdomen, groin, etc.

[0068] If the second magnet 120 is made of a single permanent magnet and generates a predetermined tensile force (2N or more) as described later, for example, the second magnet 120 can be configured with the following dimensions.

[0069] The longitudinal dimension (length) L2 of the second magnet 120 can be, for example, 50 mm or more and 100 mm or less. The transverse dimension (thickness) H of the second magnet 120 can be, for example, 20 mm or more and 50 mm or less. The depth dimension (width) W of the second magnet 120 can be, for example, 50 mm or more and 100 mm or less.

[0070] If the second magnet 120 is made of a permanent magnet, for example, the second magnet 120 can be made of a neodymium magnet capable of generating a relatively large magnetic force, similar to the first magnet 110. However, there are no particular restrictions on the specific material, type, manufacturing method, etc., of the second magnet 120, as long as it can generate a traction force that expands the urethra U, similar to the first magnet 110. Furthermore, there are no particular restrictions on the specific shape (outer shape and cross-sectional shape) of the second magnet 120 or the number of second magnets 120 used in the procedure.

[0071] In this embodiment, if the medical device 100 is configured to have three or more first magnets 110, the first magnet 110 and the second magnet 120 can be configured to generate a traction force of, for example, 2N or more in a procedure to dilate the urethra U.

[0072] As will be explained in the embodiments described later, in a procedure using the medical device 100, by generating a traction force of 2N or more with the first magnet 110 and the second magnet 120, it becomes possible to suitably expand the urethra U of a patient suffering from benign prostatic hyperplasia to a size that enables normal urination.

[0073] Furthermore, the medical device 100 can be used, for example, in patients suffering from benign prostatic hyperplasia (BPH) where the Young's modulus of the biological tissue (adenoma of the prostate P) at the implantation site of the first magnet 110 is 30 kPa or more and 46 kPa or less. As will be explained in the embodiments described later, by performing a procedure using the medical device 100 on such patients, the urethra U, which is compressed by the enlarged prostate P, can be expanded to a predetermined size, thereby improving and alleviating various symptoms associated with benign prostatic hyperplasia.

[0074] Next, with reference to Figures 4 and 5, the implantation procedure for the first magnet 110 and the usage procedure for the medical device 100 will be explained. The procedures described below are examples, and the implantation procedure and the configuration of the device used for implantation are not limited to those described here.

[0075] As shown in Figure 4, when the surgeon or other personnel perform the procedure of implanting the first magnet 110 into the prostate P, they prepare a predetermined insertion device (indwelling device) 200.

[0076] The insertion device 200 comprises an ultrasound probe 210 configured to be inserted into the rectum R through the anus of the subject, and an insertion needle 220 configured to be punctured into the prostate P, which is the implantation site for the first magnet 110. The insertion device 200 may also be composed of a medical device equipped with a known ultrasound examination instrument and biopsy needle used in prostate biopsy, for example. In the illustrated example, a device configuration in which the ultrasound probe 210 and the insertion needle 220 are integrated is illustrated, but these may also be configured to be separate from each other.

[0077] As shown in Figure 4, the operator confirms the condition of the prostate P and urethra U and the implantation position of the first magnet 110 using an ultrasound probe 210 inserted into the rectum R. After performing the above confirmation, the operator inserts an insertion needle 220 from between the scrotum and the anus toward the prostate P, inserting a portion of the tip of the insertion needle 220 into the prostate P.

[0078] The insertion needle 220 is provided with a lumen into which the first magnet 110 can be inserted. After inserting the insertion needle 220 into the prostate P, the operator delivers the first magnet 110 into the prostate P through the lumen of the insertion needle 220. The operator can implant the first magnet 110 into the prostate P using this transperineal approach. The first magnet 110 may be pre-inserted into the lumen of the insertion needle 220 before inserting the insertion needle 220 into the prostate P, or it may be inserted into the lumen of the insertion needle 220 after inserting the insertion needle 220 into the prostate P.

[0079] When implanting multiple first magnets 110 into the prostate P, the operator repeatedly inserts an insertion needle 220 into the prostate P and implants the medical device 100 via the insertion needle 220.

[0080] After implanting the first magnet 110 into the prostate P, the operator places the second magnet 120 at a predetermined position on the subject's external body O, as shown in Figure 5. Once the operator places the second magnet 120 at the predetermined position, the magnetic force between the first magnet 110 and the second magnet 120 can generate a traction force to expand the urethra U relative to the prostate P. This allows the urethra U to expand towards the external body O where the second magnet 120 is placed, as shown in Figure 6. The operator can maintain the urethra U in an expanded state while generating a traction force between the first magnet 110 and the second magnet 120.

[0081] The operator can increase or decrease the amount of urethral U expansion, or stop the urethral U from expanding, by widening or narrowing the distance between the first magnet 110 and the second magnet 120 while the urethral U is expanded.

[0082] As described above, the medical device 100 according to this embodiment includes one or more first magnets 110 that are implanted in the prostate gland P located around the urethra U to be dilated, and one or more second magnets 120 that can be placed outside the body O of the subject in which the first magnets 110 are implanted, and that generate a traction force between themselves and the first magnets 110 to dilate the urethra U.

[0083] With the medical device 100 configured as described above, the magnetic force between the first magnet 110 implanted in the prostate P and the second magnet 120 placed outside the patient's body O can generate a traction force in the prostate P to expand the urethra U. This allows for the expansion of the urethra U, which is compressed by the enlarged prostate P, thereby improving and alleviating urinary dysfunction associated with benign prostatic hyperplasia. Furthermore, with the medical device 100, the first magnet 110 can be implanted in the prostate P via a transperineal approach, eliminating the need for general anesthesia during the procedure. In addition, while procedures using medical devices that involve placing anchors or other components in the urethra via a transurethral approach require the creation of a perforation connecting the urethra U to the outside of the prostate P, this procedure is unnecessary when using the medical device 100. Therefore, the medical device 100 can effectively expand the patient's urethra U and further reduce the burden on the patient.

[0084] <Examples> Next, embodiments of the present invention will be described with reference to Figures 7 to 9. In the description of the embodiments, the same reference numerals as those used for each member and component described in the embodiments described above will be used. However, the scope of the present invention is not limited to the contents of the embodiments described below.

[0085] In the example, the amount of urethral dilation was simulated when a predetermined tensile force was generated by a first magnet 110 implanted in a prostate P having a predetermined hardness (Young's modulus) and a second magnet 120 placed outside the body O. Figure 7 shows a simulated image of the urethra U before dilation, and Figure 8 shows a simulated image of the urethra U after dilation.

[0086] In the simulation for the embodiment, the following conditions were set. The cross-sectional shape of the prostate gland P before dilation was assumed to be a circle (perfect circle) with a diameter of 30 mm. The simulation was performed using either one (only magnet 110A) or three (magnets 110A, 110B, and 110C). Figures 7 and 8 show the simulation images when three magnets 110 were used. In the example using three magnets 110, a 3 mm gap was set between each magnet 110 along the transverse direction of the cross-section. The first magnet 110 has a prism shape with a 3mm x 3mm square cross-section and a length of 30mm in the longitudinal direction. The Young's modulus of the prostate gland (P) tissue (adenoid) was set to 38 kPa. This is for the following reason: It is known that the Young's modulus of the prostate gland tissue in patients with benign prostatic hyperplasia (BPH) is approximately between 30 kPa and 38 kPa. Therefore, in this embodiment, the Young's modulus was set to 38 kPa to simulate the prostate gland tissue in a patient with BPH. Furthermore, it was assumed that soft tissue B with the same Young's modulus as the prostate gland P was present around the prostate gland P. When dilating the urethra U, the second magnet 120 was positioned on the upper side as shown in Figures 7 and 8, generating an upward traction force on the prostate P and urethra U. The traction force was set to 0.5N, 1N, and 2N when the number of embedded first magnets 110 was 1 and 3, respectively.

[0087] Figure 9 shows the simulation results.

[0088] The urethral dilation amount in Figure 9 is the displacement Lb of the urethra U (vertical displacement in the cross-section) shown in Figure 8. Note that the initial length La of the urethra U, shown in Figure 7, was set to 4 mm before the simulation began (before applying traction force).

[0089] As shown in Figure 9, it can be confirmed that the amount of urethral dilation increases with increasing traction force, regardless of whether the number of first magnets 110 is one or three. Furthermore, comparing the case using one first magnet 110 with the case using three magnets, it can be confirmed that the amount of urethral dilation is greater when three magnets are used at all traction forces.

[0090] The inner diameter of a typical urinary catheter used to forcibly drain urine from patients with urinary dysfunction is approximately 3 mm. Therefore, if the urethral dilation is 3 mm or more, it can be considered that the urethra U has been dilated to a size that allows for normal urination. As shown in Figure 9, it can be confirmed that when three first magnets 110 are implanted and a traction force of 2 N is generated, the urethra U dilates to 3.290 mm. Therefore, it is considered that in procedures using the first magnet 110, if three first magnets 110 are used and a traction force of 2 N or more is applied, it is possible to dilate the urethra U to a degree that allows for normal urination even when the urethra U of a patient is completely obstructed due to benign prostatic hyperplasia.

[0091] Although the medical device according to the present invention has been described above through embodiments and examples, the present invention is not limited to the configuration described in the embodiments and can be modified as appropriate based on the claims. [Explanation of Symbols]

[0092] 100 medical devices 110 First Magnet 110A First Magnet 110B 1st magnet 110C 1st magnet 117a 1st pole 117b 2nd pole 120 Second Magnet 127a 1st pole 127b 2nd pole 200 Insertion Devices 220 Insertion needles P Prostate U urethra Up Prostate urethra ☐ External to the body

Claims

1. A medical device used to dilate the urethra, One or more first magnets are implanted in the prostate gland, located around the urethra to be dilated, A medical device comprising one or more second magnets that can be positioned outside the body of a subject to which the first magnet is implanted, and which generate a traction force between themselves and the first magnet to expand the urethra.

2. The medical device according to claim 1, comprising two or more of the first magnets.

3. The medical device according to claim 2, wherein each of the two or more first magnets is arranged at a predetermined distance from each other at least in the transverse direction in the cross-section of the prostate.

4. Having three or more of the first magnets, A medical device according to claim 2 or 3, which generates the aforementioned traction force of 2 N or more.

5. The medical device according to claim 1, for use in a patient suffering from benign prostatic hyperplasia, wherein the Young's modulus of the biological tissue at the implantation site of the first magnet is 30 kPa or more and 46 kPa or less.

6. The medical device according to claim 1, wherein the first magnet is a rod-shaped magnet having a longitudinal direction extending along the direction of implantation into the prostate.

7. The medical device according to claim 6, wherein the first magnet is a rod-shaped magnet having a magnetization direction in the short-side direction.

Images