JP7848964B2 - Medical devices - Google Patents

Description

This invention relates to a medical device.

Medical instruments are known for grasping suture needles and grasping and fixing biological tissue during surgical suturing (for example, Patent Document 1).

Japanese Patent Publication No. 2018-102719

In surgical procedures, after suturing tissue with a suture needle, a tightening action is performed by pulling the suture. This action eliminates slack in the suture, resulting in the desired suture state and allowing for faster and cleaner wound closure. Depending on the surgeon, this tightening action may be performed by holding the instrument used for suturing (such as a forceps) in the hand, hooking the suture onto the instrument, and pulling the suture.

However, when the thread is hooked onto the device, it may slip off the surface of the device, requiring the thread to be hooked and pulled again, which can delay the thread tightening process.

Therefore, one aspect of the present invention aims to facilitate the use of instruments for suture tightening during surgical procedures.

To solve the above problems, one aspect of the present invention provides a medical instrument having a pair of arms, each having opposing surfaces, and capable of gripping an object between the opposing surfaces at the tips of the arms, wherein a groove is formed on the outer circumferential surface of the tip, other than the opposing surfaces, along a transverse direction perpendicular to the longitudinal direction of the arm.

According to one aspect of the present invention, the suture tightening procedure using an instrument can be facilitated in surgical procedures.

This is a perspective view of a forceps using one embodiment of the present invention. This figure shows an example of how to use the groove. This is a partial plan view of one of the arms in Figure 1, seen from the side. This is a partial plan view of one of the arms in Figure 1, seen from the outside. This is a cross-sectional view taken along line A-A in Figure 4. This is a cross-sectional view taken along line B-B in Figure 4. This is a cross-sectional view of an arm portion with a groove, corresponding to a modified example, as shown in Figure 6.

Figure 1 shows a perspective view of a medical device 100 according to one embodiment of the present invention. Figure 1 illustrates a surgical clamping device, specifically a forceps, as an example of the medical device 100. In this specification, "surgical clamping device" refers to an instrument that has the function of clamping an object in surgical procedures. Here, the object may be surgical instruments and materials such as sutures, sutures, gauze, etc., or human tissues such as internal organs, muscles, and blood vessels.

As shown in Figure 1, the medical instrument 100 comprises a pair of elongated arms 10, 10. Each of the arms 10, 10 is generally a plate-like piece (with a thickness dimension smaller than its length and width dimensions), and is arranged symmetrically with respect to its inner surfaces (also called opposing surfaces) F1, F1 facing each other. The arms 10, 10 are joined at the base end side of each arm 10 (the base end side of the medical instrument 100), forming a joint R3, while at the tip end they can move closer together and further apart. Furthermore, the arms 10 may have a tip portion R1, which is the portion from the tip edge to a predetermined length, and a central portion R2, which extends from the tip portion R1 toward the base end for a predetermined length. The tip portion R1 is the part that grips the object, and the central portion R2 is the part that directly receives the external force when an external force is applied. The proximity and separation of the arms 10, 10 are made possible by the external force applied to the central part R2. In the example shown in Figure 1, the user can hold the central part R2 and push so that the arms 10, 10 move closer together.

In this specification, the longitudinal direction of the tip R1 of the arm portion 10 is denoted as L, the width direction perpendicular to the longitudinal direction L as W, and the thickness direction perpendicular to both the longitudinal direction L and the width direction W as D (Figure 1). In the embodiment shown in Figure 1, the arm portion 10 is generally plate-shaped even at the tip R1; that is, the thickness (length in the thickness direction D) is smaller than the width (length in the width direction W). However, the arm portion 10 may have a shape in which the thickness (length in the thickness direction D) is equal to or greater than the width (length in the width direction W).

The materials constituting the medical device 100 are not limited and may include metals, resins, etc. Examples of metals include stainless steel and titanium. Examples of resins include polyethylene, polypropylene, polycarbonate, and engineering plastics. From the viewpoint of ensuring reliable thread tightening (described in further detail later), metal devices are preferred. Furthermore, from the viewpoint of being inexpensive to manufacture and easy to mold, resin devices are preferred.

In this specification, the circumferential surfaces of the arm portion 10, excluding the inner surface F1, are referred to as the outer circumferential surfaces F2. When the arm portions 10, 10 are brought close together and closed, the inner surface F1 is hidden, and the outer circumferential surfaces F2 of the arm portion 10 are exposed to the outside. Furthermore, the outer circumferential surfaces F2 include an outer surface F2e located on the opposite side of the inner surface (opposing surface) F1, and side surfaces F2s, F2s extending on both sides of the outer surface F2e, which are transition surfaces between the outer surface F2e and the inner surface F1.

As shown in Figure 1, grooves 5a, 5b, ... (collectively referred to as groove 5) are formed on the circumferential surface of the tip R1 of the arm portion 10 of the medical instrument 100, along a direction perpendicular to the longitudinal direction L of the arm portion 10. More specifically, grooves 5a, 5b, ... are formed on the outer circumferential surface F2 of the circumferential surface of the tip R1 of the arm portion 10. In this specification, "along a predetermined direction" includes not only a direction perfectly parallel to the predetermined direction, but also a direction deviating from the predetermined direction by within 10°, preferably within 5°.

The groove 5 formed on the outer surface F2 of the tip R1 of the arm portion 10, as shown in Figure 1, offers the following advantages during surgical procedures. When suturing tissues (organs, muscles, skin, blood vessels, etc.) during surgery, a tightening action is usually performed, where the suture is pulled and tightened after the tissue has been sutured with a suture needle and suture thread. The tightening action is important for ensuring better adhesion of the wound surface after the tissue has been sutured. By performing the tightening action appropriately, in the case of a single knot (single ligation), the ligation can be performed firmly and reliably. In the case of continuous suturing, it is possible to prevent loosening during suturing, which would impair the adhesion of the wound surface. In the case of continuous suturing, the tightening action may be performed after each stitch, after suturing the tissue multiple times, or at the time of ligation or immediately before. Such suture tightening actions may be performed with one or both hands after temporarily releasing the medical instrument (forceps, etc.) used for suturing. However, depending on the surgeon (user of the medical instrument), the suture tightening may be performed by hooking the looped thread onto the instrument and pulling it while continuing to hold the instrument used for suturing. Here, if the thread slips off the surface of the medical instrument when it is hooked onto it, it may be necessary to hook and pull the thread again, resulting in a loss of time. Also, the impact of the thread slipping off the surface of the instrument may affect the suture state of the tissue. In contrast, as in this embodiment, a groove 5 (Figure 1) is formed on the outer peripheral surface F2 of the tip R1 of the arm portion 10 of the medical instrument 100, which prevents the thread from coming off the instrument and allows for more reliable suture tightening. For example, as shown in Figure 2, the surgeon inserts the tip R1 of the medical instrument (forceps) 100 held in the right hand into the loop of the suture thread ST. At this time, by adjusting the position of the thread along the longitudinal direction L of the medical instrument 100, the loop of the suture thread ST can be hooked into one of the multiple grooves formed on the outer peripheral surface F2 of the tip R1 (groove 5b in the example of Figure 2). Then, with the suture thread ST extending in the width direction W of the arm portion 10, the medical instrument 100 can be further moved in the width direction W of the arm portion 10 to pull the thread in the width direction W and tighten it. At this time, since the thread caught in groove 5 becomes less likely to slip, the surgeon can perform the thread tightening operation more easily and reliably. Since thread tightening is a procedure often required during surgical procedures, if the thread tightening operation can be performed smoothly using the medical instrument 100 according to this embodiment, the entire surgical process can be carried out accurately and quickly.

Furthermore, as in this embodiment, the medical instrument 100, which utilizes the groove 5 formed on the outer circumferential surface F2 of the arm portion 10 for tightening sutures, can be suitably used in all suturing methods in surgical procedures. However, because the tightening operation can be performed while holding the suture needle, it is particularly suitable for continuous suturing.

The groove 5 formed on the outer circumferential surface F2 of the tip R1 of the arm portion 10 can be formed at a predetermined position by cutting, etching, or the like after manufacturing a medical instrument 100 without grooves using conventional methods. Alternatively, if the medical instrument is molded by casting, injection molding, or the like, the groove 5 can be formed using a casting mold that has grooves at predetermined positions.

The following provides a more detailed description of the groove 5. Figure 3 shows an enlarged plan view of a portion of one arm portion 10 (mainly the tip portion R1) of the medical instrument 100 in Figure 1, viewed in the width direction W, i.e., an enlarged plan view from one side F2s of the arm portion 10. Figure 4 shows an enlarged plan view of a portion of the arm portion 10 (mainly the tip portion R1) of the medical instrument 100 in Figure 1, viewed in the thickness direction D, i.e., an enlarged plan view from the outer surface F2e of the arm portion 10. Figure 5 shows a partial cross-sectional view along line A-A in Figure 4, i.e., a cross-sectional view of the area near the surface of the outer surface F2e of the arm portion 10, cut along the longitudinal direction L of the arm portion 10 at a position including the groove 5. Figure 6 shows a cross-sectional view along line B-B in Figure 4.

As shown in Figures 1, 3, and 4, in the medical instrument 100 according to this embodiment, multiple grooves 5a, 5b, 5c, 5d, 5e, and 5f are formed spaced apart from each other on one arm portion 10. However, the number of grooves formed on one arm portion 10 of the medical instrument 100 may be one, or two or more other than six, as long as the suture tightening operation described above can be easily performed. Having two or more grooves 5 per arm portion is preferable because it increases the opportunities to hook the suture onto the tip portion R1 along the longitudinal direction L of the arm portion 10 during the suture tightening operation. That is, since the suture can be hooked into any of the multiple grooves 5, the surgeon can select a groove 5 according to their habits and circumstances for use in suture tightening. While this depends on the materials constituting the medical instrument 100, the depth and width of the grooves 5, etc., from the viewpoint of preventing a decrease in the strength of the tip portion R1, it is preferable that the number of grooves 5 per arm portion be eight or less.

Whether there is one groove 5 or multiple grooves in a single arm portion 10, the area in which the grooves 5 are formed on the arm portion 10 is within the tip portion R1. The specific length range of this tip portion R1 depends on the size and configuration of the medical instrument 100, but it may be a range of 10 mm to 50 mm, preferably 20 mm to 30 mm, in the longitudinal direction L of the arm portion 10 from the tip edge.

Furthermore, the positions in which each groove 5 is formed are not particularly limited, as long as a thread-tightening operation (Figure 2) using the groove 5 is possible. However, it is preferable that at least one groove 5 is formed in a position that functions as a scale line for measuring length (including depth). In order for the groove 5 to function as a scale line for measuring length, for example, the distance from the tip edge to the groove (scale line) 5 can be a length that can be visually recognized by the user and constitutes a unit for measuring length. Here, "a length that can constitute a unit for measuring length" may be, for example, 1 mm or a multiple thereof, 2.5 mm or a multiple thereof, etc., in the metric system. For example, in the inch system, it may be 0.05 inch or a multiple thereof, or 0.25 inch or a multiple thereof. Therefore, for example, the distance from the tip edge to the groove (measuring line) 5 closest to the tip edge can be set to 2.5 mm, 5 mm, 10 mm, 20 mm, etc., for users measuring length in metric units, and to 0.25 inch, 0.5 inch, 1 inch, 2 inch, etc., for users measuring length in inches.

Furthermore, in order for the groove 5 to function as a scale line for measuring length or depth, for example, the distance (pitch) between at least two grooves can be set to a unit for length measurement (as described above) that is visually recognizable by the user. Therefore, for example, the distance between grooves can be 2.5 mm, 5 mm, 10 mm, 20 mm, etc., for users measuring length in metric units, and 0.25 inch, 0.5 inch, 1 inch, 2 inch, etc., for users measuring length in inches.

To make the grooves 5 function as scale lines for length measurement, it is preferable to form multiple grooves 5 at a constant pitch or at equal intervals. In this embodiment, as shown in Figures 3 and 4, the grooves 5a, 5b, 5c, 5d, 5e, and 5f formed on one arm portion 10 are formed at equal intervals with a pitch of 5 mm along the longitudinal direction L of the arm portion 10. In the illustrated configuration, the length from the tip edge to the center line of the groove 5a closest to the tip edge is 5 mm, and the distance between the center lines of the grooves in the longitudinal direction L is equal.

Furthermore, to ensure that the user understands that groove 5 also serves as a scale line, small letters or marks such as "5 mm," "10 mm," etc., may be printed or engraved on groove 5. Alternatively, without letters or marks, or with letters or marks, the instruction manual may explain that the groove also serves as a scale line and/or what length the distance from the tip edge to the groove or the distance between grooves represents. In this case, the distance from the tip edge to the groove or the distance between grooves does not necessarily have to be a round number according to the length measurement method.

Thus, because the groove 5 also functions as a scale line, it becomes possible to measure the length of the medical instrument 100 while using it, without the need for a separate scale or other device. This allows for easy measurement of wound depth by inserting the tip R1 of the medical instrument 100 into the wound, and reliable and easy measurement of the length and width of the wound on the tissue surface by laying the tip R1 of the medical instrument 100 flat against the tissue surface. Furthermore, it is useful not only for measuring wounds but also for determining the pitch (suture interval) in the case of continuous suturing. In other words, with the medical instrument 100 according to this embodiment, the desired length or depth becomes immediately clear. Therefore, by easily measuring length or depth using the medical instrument 100, the condition of the wound can be quickly grasped. This contributes to facilitating explanations by instructors or deepening the understanding of students in educational settings. Moreover, these effects can be obtained not only when directly observing the surgical field visually, but also when observing through images, such as in videos. In situations where you are viewing the surgical field through an image rather than directly observing the actual object, it can be particularly difficult to grasp the size without a scale. However, even in such situations, you can easily determine the desired length or depth without having to bring out a specialized scale.

As described above, the groove 5 is formed on the outer circumferential surface F2 of the arm portion 10. This configuration offers the advantage that, when the groove 5 functions as a scale line, the scale line can be seen even when the arms 10 of the medical instrument 100 are closed together. This advantage cannot be obtained if the scale is marked on the inner surface of the arm portion 10.

Furthermore, the fact that groove 5 functions as a scale line means, in other words, that a groove-shaped scale line is formed. If the goal is simply to add a scale line to the tip R1 of the arm portion 10, it is possible to form the scale line using raised ridges (linear protrusions) or to form a flat scale line without irregularities by coloring or material modification. However, by having a groove-shaped scale line as in this embodiment, it is possible to prevent raised ridges from catching on biological tissue or surgical items (gauze, tampons, etc.) during surgery, and to prevent coloring or material modification from adversely affecting biological tissue.

In the configuration shown in Figure 1, grooves 5 are formed on both arms 10, 10 of the medical instrument 100, but grooves 5 may be formed on only one arm 10. However, having grooves 5 on both arms 10, 10 allows the thread to be placed in the grooves 5 regardless of the orientation in which the medical instrument 100 is used during the thread-tightening operation. For example, if the medical instrument 100 is used with the side surface F2s of the arm 10 facing upwards, as shown in Figure 2, the thread can be placed in the grooves 5 regardless of which arm 10, 10 is facing inwards, making the thread-tightening operation easier. Furthermore, if the grooves 5 function as scale lines, it has the advantage that the scale can be seen regardless of the orientation in which the medical instrument 100 is used. In addition, when grooves 5 are formed on both arms 10, 10, it is preferable that the positions of the grooves 5 in the longitudinal direction L of the arm 10 are aligned on both arms 10, 10. As a result, even when the thread is wrapped around both arms 10 during the thread-tightening operation, the thread fits securely into the grooves 5 of both arms 10, ensuring reliable thread retention.

Furthermore, the position of the groove 5 in the longitudinal direction L of the arm portion 10 does not necessarily have to be aligned on both arm portions 10, 10. For example, one arm portion 10 may have a scale line formed according to the metric system, while the other arm portion 10 may have a scale line formed according to the inch system.

The groove width w of groove 5 (Figure 5) is not particularly limited as long as it is large enough for the suture to catch on, but is preferably 10 μm or more and 1.2 mm or less, more preferably 100 μm or more and 1 mm or less, and even more preferably 300 μm or more and 800 μm or less. This range can accommodate the thickness of sutures commonly used in surgical procedures (10 μm or more and 800 μm or less). The groove width w may be constant along one groove 5, or it may vary in the middle of the groove 5. If the groove width w varies in the middle of the groove 5, the groove width w may gradually increase or decrease, or for example, the edge of the groove 5 may be wavy. Although a wavy edge of the groove 5 enhances the function of the groove 5 in holding the suture, from the viewpoint of preventing the edge of the groove 5 from catching on biological tissue or articles during surgery, it is preferable that the edge of the groove 5 be straight. The groove width w (or its average value if the groove width w fluctuates) can be the width measured at the resurface position of the outer surface F2 (the width of the groove opening 5).

If multiple grooves 5 are formed, the groove width w of each groove may be the same or different. For example, the groove width w may be smaller or larger towards the tip. Also, the groove width w of a groove 5 formed on one arm portion 10 may be the same or different from the groove width w of a groove 5 formed on the other arm portion 10. For example, the groove width w of a groove 5 formed on one arm portion 10 may be larger or smaller than the groove width w of a groove 5 formed on the other arm portion 10.

Furthermore, the depth d of the groove 5 (Figure 5) is not particularly limited as long as it is large enough for the suture to catch, but it is preferably 10 μm or more and 1.2 mm or less, more preferably 100 μm or more and 1 mm or less, and even more preferably 300 μm or more and 800 μm or less. This allows the groove 5 to accommodate the thickness of sutures commonly used in surgical procedures (10 μm or more and 800 μm or less). The depth d of the groove 5 may be constant along a single groove 5, or it may vary along the groove 5. If the depth d varies along the groove 5, the depth d may gradually increase or decrease.

If multiple grooves 5 are formed, the depth d of each groove may be the same or different. For example, the grooves 5 closer to the tip may have a smaller or larger depth d. Also, the depth d of a groove 5 formed on one arm portion 10 may be the same or different from the depth d of a groove 5 formed on the other arm portion 10. For example, the depth d of a groove 5 formed on one arm portion 10 may be greater or less than the depth d of a groove 5 formed on the other arm portion 10.

Furthermore, the groove 5 may be formed across the entire outer circumferential surface F2 of the arm portion 10, as shown in Figures 3, 4, and 6. This allows the thread to be placed in the groove 5 regardless of the orientation of the arm portion 10 during the thread-tightening operation; that is, whether the outer surface F2e of the outer circumferential surface F2 of the arm portion 10 is facing upwards, or whether any of the side surfaces F2s are facing upwards. Additionally, this provides the advantage of facilitating the thread-tightening operation whether the user holds the medical instrument 100 with their right or left hand. Moreover, if the groove 5 functions as a scale line, it provides the advantage of allowing the scale to be visible regardless of the orientation of the medical instrument 100. In other words, the scale can be seen as long as any part of the outer circumferential surface F2 is visible.

However, the groove 5 does not necessarily have to be formed across the entire outer surface F2. The configuration in which the groove 5 is formed on only a portion of the outer surface F2 is preferable from the viewpoint of preventing a decrease in the strength of the tip R1, or from the viewpoint of simplifying the process of forming the groove 5 by cutting or other means during the manufacturing of the medical instrument 100, although this depends on the materials constituting the medical instrument 100, the depth and width of the groove 5, etc.

Figure 7 (corresponding to Figure 6) shows a modified example of the groove 5. In the example shown in Figure 7, the groove 5 is formed only on the outer surface F2e of the outer circumferential surface F2, and not on the side surfaces F2s. This allows the thread to be hooked onto the outer surface F2e even when the medical instrument 100 is held with the side surface F2s facing upwards, as shown in Figure 2. Furthermore, as shown in Figure 7, it is preferable that the groove 5 extends to the transition between the outer surface F2e and the side surface F2s. When the loop of the thread is hooked onto the tip R1 of the arm portion 10 (Figure 2), the direction of the thread changes significantly at the transition between the outer surface F2e and the side surface F2s. Therefore, if the thread can be held more securely within the groove 5 at this transition, the thread-holding function of the groove 5 is enhanced. Note that the transition between the outer surface F2e and the side surface F2s corresponds to, for example, the vertex of a rectangle if the cross-section of the arm portion 10 cut along the width direction W is a rectangle.

Furthermore, as another modification, the groove 5 may be formed in at least one of the transition areas between the outer surface F2e and the side surface F2s, but not in other areas (not shown). This configuration minimizes the thread-holding function of the groove 5 during the thread-tightening operation, prevents a decrease in the strength of the tip R1, and facilitates the manufacture of the medical instrument 100.

Furthermore, the configuration of the grooves 5 formed on one arm portion 10 and the configuration of the grooves 5 formed on the other arm portion 10 (number, position, groove width, groove depth) may be the same or different. For example, multiple grooves 5 may be formed on one arm portion 10, and one groove 5 may be formed on the other arm portion 10.

As shown in Figure 1, a grip portion 7 is formed on the outer surface F2e of the central portion R2 of the arm portion 10 to prevent slippage when the medical instrument 100 is held in the hand. The grip portion 7 is a series of grooves formed on the outer surface F2e, specifically a series of linear grooves along the width direction perpendicular to the longitudinal direction of the arm portion 10. The series of linear grooves formed on the grip portion 7 are located within the central portion R2, corresponding to the area where the user's fingers rest, and are spaced longitudinally apart from the grooves 5 formed on the tip portion R1. Note that the grip portion 7 is not limited to linear grooves; it may also be constructed by forming grooves other than linear ones, attaching friction-reducing materials, etc., as long as it prevents the user's fingers from slipping.

Furthermore, as shown in Figure 1, the inner surface F1 of at least one, preferably both, tip portions R1 of the arms 10, 10 may have a roughened surface portion 8. The roughened surface portion 8 may, for example, be fine irregularities formed on the inner surface F1. The presence of the roughened surface portion 8 provides a function, known as a needle-holding function, which allows for a more secure grip of the suture needle when it is grasped by the tip portion R1 of the medical instrument 100. Therefore, when inserting and removing the suture needle from tissue, the needle can be moved smoothly without the need for assistance such as a needle holder. The roughened surface portion 8 can be configured using known configurations for the needle-holding function. As long as it can roughen part or all of the inner surface F1 of the tip portion R1, the roughened surface portion 8 may take the form of an imprinted irregularity on the inner surface F1, or a roughened or high-friction sheet attached to the inner surface F1, etc.

Furthermore, as shown in Figure 1, hooks 9a and 9b are formed on the tip edges R1 of the arms 10, 10 of the medical instrument 100, so that they interlock when the arms 10, 10 are closed. In the example shown in Figure 1, the hook 9a on one arm 10 is a convex portion that protrudes from the inner surface F1 in the width direction W at the center of the thickness direction D, and the hook 9b on the other arm 10 is a concave portion shaped to fit the convex hook 9a. This interlocking of the hook 9a (convex portion) and hook 9b (concave portion) allows for a firm grip and dissection of tissue. When the medical instrument 100 has both the roughened portion 8 and the hook 9 described above, it becomes a hooked forceps with a needle-holding function. By using such a hooked forceps with a needle-holding function, surgical procedures, particularly suturing using suture needles and sutures, can be made even smoother. Note that the configuration of the hooks 9a and 9b is not limited to those shown in the illustration; any known hook configurations for hooked forceps can be used.

The embodiments of the present invention have been described above using medical, particularly surgical, forceps as an example. However, the embodiments of the present invention are not limited to forceps and are applicable to any instrument used in surgical procedures. They are preferably configured as various instruments used for suturing and related actions (techniques) in surgical procedures. Furthermore, they are particularly preferably configured as surgical clamping devices (medical instruments having a pair of arms, where each arm has opposing surfaces that can clamp an object between them). Specific examples of forms other than forceps include forceps, needle holders, scissors, and other instruments that may catch sutures during surgery. The size of the medical instruments according to this embodiment is also not limited; for example, the instrument may be used while visually confirming its operation, or it may be used while confirming its operation using a magnifying glass, endoscope, etc.

Furthermore, the configuration of grooves and other elements is not limited to the embodiments described above. The embodiments shown herein can be modified, altered, replaced, added, deleted, and combined in various ways within the scope of the claims, and these also fall within the technical scope of the present invention.

5, 5a to 5f groove 7 grip part 8 roughened part 9a, 9b hook part 10 arm part 100 medical instrument (surgical lever)
F1 Opposing surface (inner surface)
F2 Outer surface F2s Side of the outer surface F2e Outer surface of the outer surface R1 Tip R2 Center R3 Joint

Claims (10)

A medical device having a pair of arms, each having opposing surfaces facing each other, and capable of gripping an object between the opposing surfaces at the tips of the arms,
On the outer circumferential surface of the tip portion other than the opposing surface, a plurality of grooves are formed along the transverse direction perpendicular to the longitudinal direction of the arm portion, with an opening width of 10 μm or more and 1.2 mm or less, and a depth of 10 μm or more and 1.2 mm or less, as measured at the position of the outer circumferential surface.
A medical instrument in which the plurality of grooves are formed continuously over the entire outer surface of at least one of the arm portions, function as scale lines for length measurement, and are formed at intervals corresponding to a predetermined unit of length. The plurality of grooves are formed in each of the pair of arms, and are formed at intervals corresponding to different unit systems between the pair of arms, as described in claim 1. The medical device according to claim 1, wherein the width of each groove varies, either by gradually increasing or decreasing the groove width, or by the groove edge becoming wavy. The medical device according to claim 1, wherein the grooves in one arm portion have a groove width that decreases or increases towards the tip. The plurality of grooves are formed in each of the pair of arms, and the widths of the grooves differ between the pair of arms, as described in claim 1. The medical device according to claim 1, wherein the depth of each of the multiple grooves gradually increases or decreases. The medical device according to claim 1, wherein the depth of the grooves in one arm portion decreases or increases as the groove approaches the tip. The plurality of grooves are formed in each of the pair of arms, and the depths of the grooves differ between the pair of arms, as described in claim 1. The medical instrument according to claim 1, wherein the forceps have a hook portion formed at their tip. The medical device according to claim 1, wherein the opposing surface of the tip portion has irregularities.