Highly shape-stable wound retractor

Abstract

Provided is a highly shape-stable wound retractor, which is for holding an opened part in a human body undergoing incision in an opened state, and which demonstrates shape stability during use. The highly shape-stable wound retractor is characterized: by containing, as a main resin component, a synthetic resin that has chemical resistance and is an elastic material; by being configured such that the wound retractor is curved elastically from a sheet-like state so that a first end and a second end overlap each other in the thickness direction to form a ring; and in that a through-hole through which the second end can pass is formed in the vicinity of the first end, and the diameter of the ring can be varied by changing the length over which the second end is passed through the through-hole.

Description

High form stability retractor

[0001] The present invention relates to a retractor, and more particularly to a highly shape-stable retractor for holding open the wound portion of a human body to be incised in surgery performed directly by a doctor or in so-called robotic surgery performed by a doctor using a robot.

[0002] There is a conventional retractor in which a thin plate made of an elastic material is inserted into a wound area in a rolled state, and when the hand that rolled it up after insertion is released, the elastic force of the thin plate causes the plate to expand by itself, increasing the diameter of the cylinder (Patent Document 1). Of these conventional retractors, the retractor shown in Figures 32A and 32B does not have any accessories other than the thin plate, so there is no need to worry about the accessories getting caught on parts of the human body when it is inserted into the wound area.

[0003] Since such a wound retractor holds the wound area open by its own elasticity, there is less need to pull the wound area with hooks, and there is less risk of the human body being injured by the hooks.

[0004] JP 2007-82674 A

[0005] 32A and 32B are perspective views of a conventional retractor. As shown in Fig. 32B, which shows the retractor in use, this retractor is cylindrical with the same diameter from top to bottom. During surgery, an instrument held by the surgeon's fingers or a robotic arm enters through the upper opening of this cylinder and treats the affected area located at the lower opening of the cylinder.

[0006] In this case, the instrument may come into contact with the upper edge of the cylinder, which may damage the retractor, or may cause the retractor to tilt or the overlapping portion of the retractor to shift. Also, in order to reach the tip of the instrument to the affected area, it is difficult to tilt the instrument horizontally and hold it without touching the cylinder.

[0007] Furthermore, if the expansion due to the elastic force continues, there is a high risk that the ends that should be overlapping will become separated from each other.

[0008] In view of the above problems, an object of the present invention is to provide a retractor that maintains a stable shape when in use.

[0009] (1) The present invention provides a highly dimensionally stable retractor that contains a synthetic resin that is chemical-resistant and elastic as its main resin component, that has a first end and a second end spaced apart from the first end and that has a width direction when unfolded into a plate, that is configured to bend elastically from the plate state so that the first end and the second end overlap in the thickness direction of the plate state to form a ring, that has a through-hole in the portion near the first end that is near the first end, through which the second end can be passed, and that the diameter of the ring can be changed by changing the length of the passage of the second end through the through-hole.

[0010] In other words, the highly shape-stable retractor of the present invention is configured to bend from a plate state to form a loop, rather than forming a cylindrical shape like conventional retractors. Therefore, there is little risk of it being damaged by surgical instruments or its shape becoming unstable due to contact with the instruments. Furthermore, a wide field of view can be secured for observing the affected area.

[0011] Furthermore, since the highly dimensionally stable retractor of the present invention contains a chemical-resistant synthetic resin as its main resin component, it can be washed with chemicals after each surgical use and can be reused. Furthermore, the inclusion of a synthetic resin makes it easy to mold into a thin plate shape.

[0012] Furthermore, because the highly configurable retractor of the present invention has a through-hole near the first end, there is little risk of the first end and the second end separating when the second end is inserted through the through-hole. This stabilizes the shape during use. Furthermore, the first end and the second end are securely in contact with each other, generating friction between them. This reduces the possibility of the ring of the highly configurable retractor of the present invention suddenly expanding or contracting, thereby stabilizing the shape during use.

[0013] (2) Furthermore, the second end vicinity portion, which is in the vicinity of the second end, may have an engaging portion that protrudes in the width direction beyond the through hole when the second end is passed through the first end vicinity portion.

[0014] That is, even when the highly shape-stable retractor forming the loop tries to expand, the locked portion is caught around the through-hole, and the portion near the second end is locked by the portion near the first end in the direction that tends to contract the loop, thereby preventing further expansion. This makes it possible to stabilize the shape when in use.

[0015] (3) The locking member may also have a pair of locking portions, each of which protrudes outward in both directions in the width direction, and at least the locking portion provided on one side in the width direction may be formed so as to protrude from a constricted portion that is adjacent to the first end in a direction approaching the first end and is recessed inward in the width direction.

[0016] That is, since it has a pair of engaging portions that protrude in both width directions, each engaging portion catches around the through hole, and the portion near the second end is efficiently engaged by the portion near the first end.

[0017] Furthermore, since the engaging portion on one side protrudes from the constricted portion, the engaging portion on the other side can pass through the through hole even if the through hole is narrower because of the narrower constricted portion. By narrowing the width of the through hole in this way, the engaging portion can easily catch around the periphery of the through hole, and the portion near the second end can be more efficiently engaged by the portion near the first end.

[0018] (4) Furthermore, the inner peripheral edge of the through hole may have a shape having a line segment between two points, and the line segment between the two points may be inclined so that of these two points, a first point located closer to the first edge in the width direction is closer to either the first end or the second end than a second point located closer to the second edge in the width direction.

[0019] Incidentally, when a highly shape-stable retractor in a rolled-up state fits into the internal organs, muscles, etc. surrounding the affected area (hereinafter, the internal organs, muscles, etc. surrounding the affected area will be simply referred to as "surrounding internal organs, etc."), the surrounding internal organs, etc. do not necessarily have a columnar space with the same cross section, such as a cylindrical or rectangular prism. In many cases, the space held by the surrounding internal organs, etc. is partially or entirely formed in a shape close to a truncated cone, such as a truncated cone, with a diameter that narrows or widens toward the interior.

[0020] Therefore, in the highly configurable retractor of the present invention, because the line segment of the through hole is inclined, when the second end passes through the through hole in a direction perpendicular to the inclined line segment, the extensions of the generatrix lines at different positions from the first end to the second end intersect or approach each other, causing the outward surface to form part of the side of a substantially truncated cone. For example, if the length of the through hole in the inclined line segment is only slightly greater than the width of the second end of the highly configurable retractor, the second end will easily pass through the through hole in a direction perpendicular to the inclination direction, but will be easily caught around the through hole in a direction not perpendicular to the inclination direction, making it difficult to pass through the through hole. Therefore, with the highly configurable retractor of the present invention, the inclined line segment of the through hole allows the diameter to be changed slightly while the outward surface forms part of the side of a substantially truncated cone. As a result, the outward surface can easily follow the shape of part or all of the space of the surrounding internal organs, etc., and fits well after insertion into the retraction.

[0021] (5) In addition, the central portion, which is the portion sandwiched between the portion near the first end and the portion near the second end, may have a center line in the width direction that forms an arc in the unfolded state.

[0022] That is, because the center line of the central portion describes an arc, the highly shape-stable retractor of the present invention forms a curved shape by curving from a plate state to form a loop, and the outward surface forms the side surface of an approximately truncated cone. The inward surface forms the back surface of the side surface. At this time, the inner half of the arc-shaped center line forms a curved surface that is inclined to form the side surface of the narrowing half of the approximately truncated cone. Similarly, the outer half of the center line forms a curved surface that is inclined to form the side surface of the widening half of the approximately truncated cone.

[0023] As a result, when the highly shape-stable retractor of the present invention is curved to form a loop, the outward surface can easily conform to the shape of part or all of the space of the surrounding internal organs, etc., and fits well after being inserted into the retraction area.

[0024] (6) Furthermore, the inner peripheral edge of the through hole may have a shape having a line segment between two points, and in the unfolded state, the line segment between the two points may be inclined with respect to the width direction so that an extension line of the line segment between the two points extending inward of the arc passes through a position farther from the arc than the center point of the arc.

[0025] The inventors discovered that because the highly configurable retractor of the present invention has an arc-shaped centerline, the elastic force generated when the retractor curves from a plate shape to form a loop tends to cause the three-dimensional shape of the retractor to assume a helical shape after winding. Specifically, if the second end is not passed through the through-hole, the portions near the first end and the second end after winding tend to be misaligned toward the axial center of the truncated cone, resulting in a helical shape. Furthermore, the inventors discovered that when the second end of such a highly configurable retractor is passed through the through-hole, the portion near the second end tends to protrude toward the expanded diameter side of the truncated cone, resulting in a failure to overlap with the portion near the first end from the previous turn. Thus, the highly configurable retractor is subjected to a force that biases the second end toward the expanded diameter side of the truncated cone. Under this condition, the outward and inward surfaces of the highly configurable retractor may form distorted front and back surfaces of the truncated cone, respectively.

[0026] In contrast, the through hole of the highly configurable retractor of the present invention is inclined so that an extension of the line segment extending inward of the arc passes farther from the arc than the center line of the arc. Therefore, it was discovered that the second end that has made a full circle and passed through the through hole tends to move toward the narrowing side of the truncated cone, which is in a direction perpendicular to the inclination direction, rather than along the arc. In other words, it was discovered that the second end easily passes through the through hole in a direction perpendicular to the inclination direction, but that it tends to get caught around the through hole and has difficulty passing through in a direction not perpendicular to the inclination direction. Therefore, a force is applied to the highly configurable retractor that biases the second end toward the narrowing side of the truncated cone, which is the easier side to pass through.

[0027] As described above, in the highly shaped retractor of the present invention, because the center line forms an arc and the through hole is inclined in a predetermined direction, it is possible to balance the force that tends to bias the second end toward the enlarged diameter side of the truncated cone with the force that tends to bias the second end toward the reduced diameter side. As a result, the second end is less likely to bias toward either the enlarged diameter side or the reduced diameter side, and the outward and inward surfaces of the highly shaped retractor can form the front and back surfaces of the truncated cone without distortion. Therefore, the outward surface can easily follow the shape of part or all of the space of the surrounding internal organs, etc., and fits well after insertion into the retraction portion.

[0028] (7) The plate thickness in the thickness direction may be 0.1 mm or more and less than 0.5 mm.

[0029] Through trial and error, the inventors discovered that even with a ring-forming configuration, when the plate thickness of the highly shaped retractor of the present invention is 0.1 mm or more and less than 0.5 mm, the highly shaped retractor causes less injury to the affected area and the ring shape is more stable. Specifically, the inventors discovered that if the plate thickness is less than 0.1 mm, the edges of the thin plate are too sharp when attached to the wound, potentially causing injury to the affected area or the area around the affected area. On the other hand, if the plate thickness is 0.5 mm or more, the elasticity of the thin plate is too strong, making it impossible to maintain an overlapping configuration in which the first end and the second end are aligned. For example, the first end and the second end are not aligned, resulting in a configuration in which the first end and the second end are misaligned.

[0030] As a result, the highly shape-stable retractor of the present invention can easily stabilize the shape during use.

[0031] (8) Furthermore, the central portion, which is the portion sandwiched between the portion near the first end and the portion near the second end, may have a wavy portion on at least one edge in the width direction that undulates in the width direction.

[0032] That is, because the highly configurable retractor of the present invention has a wavy portion on at least one edge, by inserting the highly configurable retractor into the wound so that the edge having this wavy portion is located at the back, the edge having the wavy portion can abut against the affected area or its surroundings at the back. At this time, because the wavy portion is wavy, the edge having this wavy portion is less likely to slip against the affected area or its surroundings. Therefore, even when the highly configurable retractor forming a ring tries to expand further outward or contract inward, the resistance force that the wavy portion receives from the affected area or its surroundings prevents sudden expansion or contraction. This allows the highly configurable retractor of the present invention to be stabilized in a certain expanded state.

[0033] (9) Furthermore, the central portion, which is the portion sandwiched between the portion near the first end and the portion near the second end, may have an uneven portion on at least one edge in the width direction that is uneven in the width direction.

[0034] That is, the highly configurable retractor of the present invention has an uneven portion on at least one edge, and by inserting the highly configurable retractor into the wound so that the edge having this uneven portion is located at the back, the edge having the uneven portion can abut against the affected area or its surroundings at the back. At this time, because the uneven portion is uneven, the edge having this uneven portion is less likely to slip against the affected area or its surroundings. Therefore, even when the highly configurable retractor forming a ring tries to expand further outward or contract inward, the resistance force that the uneven portion receives from the affected area or its surroundings can prevent sudden expansion or contraction. This allows the highly configurable retractor of the present invention to be stabilized in a certain expanded state.

[0035] (10) Furthermore, in the central portion sandwiched between the portion near the first end and the portion near the second end, a plurality of quadrilateral portions having long sides in the width direction and recessed or protruding in the thickness direction may be provided, and in the state of forming the ring, each quadrilateral portion may be recessed radially inward of the curve or protruding radially outward on the outer surface of the curve.

[0036] That is, the highly configurable retractor of the present invention has multiple quadrilateral portions on its outer surface when bent, so that when this highly configurable retractor is inserted into the wound, the quadrilateral portions can abut against the affected area deep inside or surrounding internal organs, etc. At this time, because the quadrilateral portions are recessed or protruded on the outer surface, the central portion experiences high friction with these areas and is less likely to slip. Therefore, even when the annular highly configurable retractor attempts to expand, rotate, or move, these can be prevented by the resistance force that the quadrilateral portions receive from the affected area deep inside or surrounding internal organs, etc. This makes it possible to stabilize the shape, posture, and position of the highly configurable retractor of the present invention.

[0037] (11) The resin component may contain a polyether ether ketone resin.

[0038] That is, polyether ether ketone resin (PEEK) has heat resistance in addition to chemical resistance, so it can be cleaned using liquids such as high-temperature cleaning agents and cleaning water. This allows for more effective cleaning. Furthermore, since effective cleaning can be performed without applying a large mechanical force, there is little risk of damaging the surface during cleaning. These features allow for repeated use of a highly shape-stable retractor.

[0039] Furthermore, because polyether ether ketone resin has impact resistance and abrasion resistance, the highly shaped retractor of the present invention is unlikely to be damaged even if it comes into contact with a metal instrument. Also, in so-called robotic surgery, the highly shaped retractor is unlikely to be damaged even if it comes into contact with a remotely controlled instrument or part of a robot. These factors allow the highly shaped retractor to be used repeatedly for a long period of time. Moreover, there is no risk that damaged areas of the retractor will injure the internal organs or other parts of the human body.

[0040] As described above, the present invention provides a highly shaped retractor that maintains a stable shape during use, has a long lifespan, and is free from the risk of injuring the human body. In addition, the present invention provides a highly shaped retractor that can be easily manufactured.

[0041] 5A shows a view of the highly configurable retractor showing the first embodiment of the present invention in an unfolded state.

[0023] FIG. 5B shows a traced image of the highly configurable retractor of FIG. 1 in an assembled state, viewed from slightly below the front.

[0024] FIG. 5C shows a photograph of the highly configurable retractor of FIG. 1 in an assembled state attached to an incision in an animal's heart.

[0025] FIG. 5D shows a photograph of the highly configurable retractor of FIG. 1 in an assembled state attached to the inside of an animal's heart.

[0026] FIG. 5A shows a traced image of the highly configurable retractor of FIG. 1 in an assembled state, viewed from slightly below the back.

[0027] FIG. 5B shows a traced image of the highly configurable retractor of FIG. 1 in an assembled state, with the insertion end inserted deeper than in the state of FIG. 5A.

[0028] FIG. 5C shows a front view of the highly configurable retractor of FIG. 1 in a state where the vicinity of the through hole and the vicinity of the locked portion overlap front to back.

[0029] FIG. 5D shows a front view of the highly configurable retractor of FIG. 1 in a state where the insertion end is advanced to the right. Figures 8A and 8B show views of a highly configurable retractor in an unfolded state to illustrate first and second modified examples of the first embodiment of the present invention. Figures 9A and 9B show views of a highly configurable retractor in an unfolded state to illustrate third and fourth modified examples of the first embodiment of the present invention. Figure 10A shows a front view of a highly configurable retractor in an unfolded state to illustrate a fifth modified example of the first embodiment of the present invention. Figure 10B shows a plan view of the state shown in Figure 10A. Figure 10C shows a partial enlarged view of Figure 10B. Figures 11A and 11B show schematic views for explaining a highly configurable retractor according to a second embodiment of the present invention. Figure 12A shows a view of a highly configurable retractor according to the second embodiment of the present invention in an unfolded state. Figure 12B shows a partial enlarged view of the through-hole of the highly configurable retractor shown in Figure 12A. 13A and 13B are front views of the assembled highly configurable retractor of FIG. 12, in which the central portion of the portion adjacent to the locked portion and the portion adjacent thereto are passed through a through-hole and overlap at the rear. FIG. 13A shows the orthogonal insertion state, and FIG. 13B shows the diagonal insertion state. FIG. 13B shows a front view of the state in which the portion adjacent to the locked portion has been pulled in the opposite direction to the insertion direction from the state of FIG. 13A. FIG. 13C shows a view of the highly configurable retractor in an unfolded state to illustrate a modified example of the second embodiment of the present invention. FIG. 13D shows a view of the highly configurable retractor in an unfolded state according to a third embodiment of the present invention.16 shows a partially enlarged view of the through-hole of the highly configurable retractor of FIG. 16. A transparent model of the highly configurable retractor of FIG. 16 was created, and a traced image of the model was viewed from above the rear in an orthogonal insertion state. A front view of the highly configurable retractor of FIG. 16 shows a state in which the portion near the locked portion is pulled in the opposite direction to the insertion direction from the state of FIG. 18. A highly configurable retractor of a fourth embodiment of the present invention is unfolded. A partially enlarged view of the through-hole of the highly configurable retractor of FIG. 20 shows a partially enlarged view of the through-hole of the highly configurable retractor of FIG. 20. A transparent model of the highly configurable retractor of FIG. 20 was created, and a traced image of the model was viewed from above the rear in an orthogonal insertion state. A front view of the state in which the portion near the locked portion is pulled leftward from the state of FIG. 22. A view of the highly configurable retractor of a fifth embodiment of the present invention is unfolded. Figure 25A shows a perspective view of the highly configurable retractor of Figure 24 in an assembled state, viewed obliquely from above in the vicinity of the through-hole. Figure 25B shows a front view of the highly configurable retractor of Figure 25A, with the vicinity of the through-hole facing forward. Figure 25B shows a view of a highly configurable retractor showing a sixth embodiment of the present invention in an unfolded state. Figure 26 shows a partially enlarged view of the vicinity of the through-hole of the highly configurable retractor of Figure 26. Figure 28A shows a perspective view of the highly configurable retractor of Figure 26 in an assembled state, viewed obliquely from above in the vicinity of the through-hole. Figure 28B shows a front view of the highly configurable retractor of Figure 28A, with the vicinity of the through-hole facing forward. Figures 29A and 29B show traced images of the highly configurable retractor of Figure 24 in an assembled state, viewed obliquely from above in the vicinity of the through-hole. Figure 29C shows a traced image of the highly configurable retractor of Figure 29B when viewed from the front. Figures 30A and 30B show traced images of the highly configurable retractor of Figure 26 in the assembled state when viewed obliquely from above in the vicinity of the through-hole. Figure 30C shows a traced image of the highly configurable retractor of Figure 30B when viewed from the front. This shows a highly configurable retractor of the present invention in an unfolded state, in which the constricted portion is recessed adjacent to the center of the second locked portion. Figures 32A and 32B show perspective views of a conventional retractor.

[0042] [First Embodiment] A first embodiment of the present invention will be illustrated using Figures 1 to 10. In Figure 1, 11 denotes a highly configurable retractor. A highly configurable retractor is an instrument that stabilizes the morphology during surgery and secures the surgical field in order to keep the wound site of a human body that is incised during surgery open. The highly configurable retractor 11 of the present invention is a thin, rectangular plate when unfolded into a plate shape as shown in Figure 1. The left-right arrow L shown in Figure 1 indicates the longitudinal direction of the highly configurable retractor 11, and the up-down arrow W similarly indicates the width direction. Although not shown in Figure 1, the highly configurable retractor 11 has a thickness that is the depth direction of the figure.

[0043] The highly dimensionally stable retractor 11 has a first end, which is one longitudinal end, and a second end, which is the other end separated from the first end. The first end is located on the left side of the figure, and the second end is located on the right side of the figure. A through-hole 12 is formed in the thickness direction near the first end. A pair of locking portions 13, 14 is provided near the second end. Each locking portion 13, 14 is provided so as to protrude outward on both sides in the width direction of the highly dimensionally stable retractor 11. Of the pair of locking portions 13, 14, the first locking portion 13 faces upward in Figure 1, and the second locking portion 14 faces downward in Figure 1. The first end is also referred to as an insertion end 18, and the second end is also referred to as an insertion end 19. Furthermore, the portion near the first end is simply referred to as the portion near the first end or the through-hole portion 15, and the portion near the second end is simply referred to as the portion near the second end or the locked portion portion 16.

[0044] The central portion sandwiched between the through-hole vicinity portion 15 and the locked portion vicinity portion 16 in the longitudinal direction is called a central portion 17. The central portion 17 extends in the longitudinal direction, and both ends in the width direction are parallel to each other.

[0045] The highly configurable retractor 11 can be elastically bent from a plate state, with the insertion end 18 and the insertion end 19 overlapping in the thickness direction of the plate state and forming a generally circular ring. Figure 2 is a traced image of the highly configurable retractor 11 shown in Figure 1 , fabricated, bent from a rectangular state so that the insertion end 19 is turned to the back, and then passed through the through hole 12 from the front. In other words, the insertion end 19 is passed through the through hole 12 from the outside to the inside of the annular shape. This state is referred to as the assembled state. Arrow U indicates the upward direction of the assembled highly configurable retractor 11 in each figure, and arrow D indicates the downward direction in each figure. Arrow L indicates the leftward direction in each figure, and arrow R indicates the rightward direction in each figure. Arrow F indicates the forward direction in each figure, and arrow B indicates the rearward direction in each figure. The outward surface of the highly configurable retractor 11 in the assembled state forms the side of a roughly disk with a centerline in the up-down direction. However, the arrows U, D, L, R, F, and B do not necessarily indicate the upper, lower, left, right, front, and rear directions, respectively, when the highly configurable retractor 11 is in use. Furthermore, the highly configurable retractor 11 can be assembled not only by bending the insertion end 19 backward as shown in FIG. 2 , but also by bending the insertion end 19 forward, in which case the assembled state is shown reversed left and right. In this way, the highly configurable retractor 11 can be used in the direction most convenient for the user, such as upward, downward, left, right, front, or rear, or assembled and used with either the front or back side facing outward.

[0046] As an example, Figure 3 shows a photograph of the assembled highly configurable retractor 11 attached to an incision in an animal's heart. The highly configurable retractor 11 in Figure 3 happens to be used in the same upside-down and upside-down orientation as in Figure 2. This photograph simulates the process of fitting the assembled highly configurable retractor 11 into the incision in the heart, and inserting an instrument held by a surgeon's fingers into the assembled highly configurable retractor 11 to treat an affected area inside the heart. Because the highly configurable retractor 11 is elastic and assembled so that the insertion end 19 passes through the through-hole 12, even if a certain amount of force is applied from the outside or inside of the assembled highly configurable retractor 11 while it is attached, the highly configurable retractor 11 can absorb this force by elastically deforming or by sliding the insertion end 19 laterally relative to the through-hole 12. This allows the expanded configuration shown in Figure 3 to be stabilized. FIG. 4 shows a photograph taken by looking into the opening of the wound, showing the highly shape-stable retractor 11 attached so as to abut against the affected area at the back or its periphery.

[0047] While Fig. 2 is a traced image of the assembled highly configurable retractor 11 as viewed from slightly below the front, Figs. 5A and 5B are both traced images of the highly configurable retractor 11 as viewed from slightly below the back. Similarly to Fig. 2, Fig. 5A shows the state in which the insertion end 19 is inserted through the through-hole 12 with the left ends of the engaging portions 13 and 14 remaining close to the periphery of the through-hole 12, whereas Fig. 5B shows the state in which the insertion end 19 has slid rightward relative to the through-hole 12 and thus been inserted deeply. Furthermore, the insertion end 19 can also slide leftward from the state shown in Fig. 5B to return. Because the highly configurable retractor 11 can change the position of the insertion end 19 relative to the through-hole 12, the diameter of the substantially circular ring can be freely changed. Therefore, even if a certain amount of force is applied from the outside or inside of the highly configurable retractor 11 while it is being worn, this force can be absorbed by changing the diameter.

[0048] The state in which the insertion end 19 is passed through the through-hole 12 will be described in detail with reference to Figures 6 and 7. Similar to Figure 2, Figures 6 and 7 show the state in which the through-hole vicinity 15 located on the right side and the locked portion vicinity 16 located on the left side overlap front to back. In a front view, the insertion end 19 is hidden behind the through-hole vicinity 15. However, for clarity, all of the overlapping portions that should be shown with hidden lines are shown with solid lines. Similar to Figures 2 and 5A, Figure 6 shows the state in which the first locked portion left end 13a, which is the left end of the first locked portion 13, and the second locked portion left end 14a, which is the left end of the second locked portion 14, are close to the through-hole left edge 12a, which is the left edge of the through-hole 12, in the left-right direction.

[0049] 6, the portion 16 adjacent to the locked portion has a constricted portion 20 that is recessed downward and inward in the width direction. The constricted portion 20 is located to the left of the first locked portion 13. The first locked portion 13 is formed to protrude outward in the width direction from the constricted portion 20 so that the constricted portion 20 and the left end 13a of the first locked portion are continuous in the up-down direction. The lower half of the constricted portion 20 is formed in a roughly semicircular shape with an arc on the lower side.

[0050] 6, the through-hole width W1, which is the width of the through-hole 12 in the width direction, is shorter than the maximum width W2, which is the distance between the upper end of the first locked portion 13 and the lower end of the second locked portion 14. Therefore, in order to pass the insertion end 19 through the through-hole 12, the locked portion neighboring portion 16 is tilted clockwise CL with respect to the through-hole neighboring portion 15, and the first locked portion 13 is passed through the through-hole 12 first, and then the second locked portion 14 is passed through the through-hole 12. At this time, because the locked portion neighboring portion 16 has a constricted portion 20, after the first locked portion 13 is passed through the through-hole 12 first, the locked portion neighboring portion 16 is moved upward so that the upper edge of the through-hole 12 and the deepest part of the constricted portion 20 come into contact with or approach each other. Furthermore, since the minimum width W3, which is the distance between the deepest part of the constricted portion 20 and the lower edge of the portion 16 adjacent to the engaging portion, is shorter than the through-hole width W1, the second engaging portion 14 can easily pass through the through-hole 12.

[0051] Moreover, because the through-hole width W1 is shorter than the maximum width W2, even when the locked portion vicinity 16 is pulled leftward relative to the through-hole vicinity 15, the first locked portion 13, the second locked portion 14, or both locked portions 13, 14 are caught around the periphery of the through-hole 12 and are thereby locked rightward. In this way, the locked portion vicinity 16 is locked rightward by the through-hole vicinity 15.

[0052] Furthermore, because the normal width W4, which is the distance between the upper and lower ends of the locking portion neighboring portion 16 and the central portion 17 continuing leftward from the locking portion neighboring portion 16, is slightly shorter than the through-hole width W1, the locking portion neighboring portion 16 and the central portion 17 on the left side of the constricted portion 20 can move left and right through the through-hole 12. At this time, because the through-hole neighboring portion 15 and the locking portion neighboring portion 16 and the central portion 17 overlap in the front-to-rear direction, the locking portion neighboring portion 16 and the central portion 17 slide left and right while abutting against the periphery of the through-hole 12 at the through-hole neighboring portion 15. Figure 7 shows an example of a state in which the insertion end 19 moves rightward and the central portion 17 passes through the through-hole 12. The through-hole width W1, maximum width W2, minimum width W3, and normal width W4 described above are in the order of minimum width W3, normal width W4, through-hole width W1, and maximum width W2.

[0053] The highly dimensionally stable retractor 11 preferably contains polyether ether ketone resin as its main resin component. Polyether ether ketone resin is a material that is chemically resistant and elastic. Since the manufacturer ships the polyether ether resin in a thin plate form, the maker of the highly dimensionally stable retractor 11 shapes it into the desired shape by machining it, such as cutting and drilling. In addition to polyether ether ketone resin, chemically resistant engineering plastics such as polyphenylene sulfide resin (PPS) may also be used.

[0054] Furthermore, the thickness of the highly shaped retractor 11 is generally uniform throughout, and is preferably within the range of 0.1 mm or more and less than 0.5 mm. Through trial and error, the inventors discovered that when the highly shaped retractor of the present invention has a thickness of 0.1 mm or more and less than 0.5 mm, the highly shaped retractor is less likely to injure the affected area and the annular shape is more stable. If the highly shaped retractor 11 is too thin, there is a high risk of injuring the affected area or the area around the affected area, and if it is too thick, the repulsive force is too strong and the adjacent portions 15, 16 do not overlap in the specified positions.

[0055] With the above-described configuration, the highly shape-stable retractor 11 is configured so that the thin plate is rolled up to form a ring, and is not cylindrical like conventional retractors. Therefore, there is little risk of damage from instruments during surgery or of the retractor becoming unstable due to contact with the instruments. Furthermore, the small height ensures a wide field of view for observing the affected area.

[0056] Furthermore, because the highly shaped retractor 11 contains a chemical-resistant synthetic resin as its main resin component, it can be cleaned with chemicals after each surgical use, allowing for repeated use. Furthermore, the inclusion of a synthetic resin facilitates molding into a thin plate shape. For example, when polyetheretherketone resin is used as the main resin component, polyetheretherketone resin has heat resistance in addition to chemical resistance, allowing for cleaning with high-temperature liquids such as detergents and cleaning water. This allows for more effective cleaning. Furthermore, effective cleaning can be performed without the application of large mechanical forces, reducing the risk of damaging the surface during cleaning. These features allow for repeated use of the highly shaped retractor 11. Furthermore, because polyetheretherketone resin is impact-resistant and abrasion-resistant, the highly shaped retractor 11 is unlikely to be damaged even if it comes into contact with a metal instrument. Furthermore, even in so-called robotic surgery, the highly shaped retractor 11 is unlikely to be damaged even if it comes into contact with a remotely controlled instrument or part of a robot. These features allow for long-term repeated use of the highly shaped retractor 11. Moreover, there is no risk that the damaged portion of the retractor will injure the internal organs or other parts of the human body.

[0057] Furthermore, because the highly shaped retractor 11 has the through hole 12 formed in the through hole vicinity 15, there is little risk that the through hole vicinity 15 and the locked portion vicinity 16 will separate when the insertion end 19 is inserted through the through hole 12. This stabilizes the shape during use. Also, the through hole vicinity 15 and the locked portion vicinity 16 come into contact with each other, generating friction between them. This reduces the possibility that the ring of the highly shaped retractor 11 will suddenly expand or contract, thereby stabilizing the shape during use.

[0058] Next, even when the annular, highly shape-stable retractor 11 tries to expand, the respective engaged portions 13, 14 are caught around the through-hole 12, and the portion 16 in the vicinity of the engaged portion is engaged by the portion 15 in the vicinity of the through-hole in the direction that tends to contract the ring, thereby preventing further expansion. This makes it possible to stabilize the shape when in use.

[0059] Furthermore, because the locked portion neighboring portion 16 has the constricted portion 20, the minimum width W3 is shorter than the through-hole width W1. Therefore, even if the through-hole width W1 is short, both locked portions 13, 14 can be passed through the through-hole 12. Furthermore, by shortening the through-hole width W1, the locked portions 13, 14 can be easily caught around the periphery of the through-hole 12, and the locked portion neighboring portion 16 can be more efficiently locked by the through-hole neighboring portion 15.

[0060] Although an example has been shown in which a pair of locking portions 13, 14 protrude from the locking portion vicinity portion 16 in this embodiment, the highly shaped retractor 11 may have only one of the locking portions facing upward or downward as long as it can reliably lock the locking portion vicinity portion 16. Furthermore, although an example has been shown in which only one constricted portion 20 is recessed in the locking portion vicinity portion 16, the highly shaped retractor 11 may be provided with both an upper constricted portion and a lower constricted portion as long as the required strength can be ensured.

[0061] Next, since the plate thickness of the highly dimensionally stable retractor 11 is 0.1 mm or more, the edge of the thin plate is unlikely to be too sharp when attached to the wound site and cause injury to the affected area or the area around the affected area. On the other hand, since the plate thickness is less than 0.5 mm, the elastic force of the thin plate is too strong, and it is possible to reduce the occurrence of a situation in which the relative positions of the through-hole vicinity 15 and the locked portion vicinity 16 are not constant, causing the hole vicinity 15 and the locked portion vicinity 16 to shift up and down, front and back, or left and right.

[0062] This allows the highly shape-stable retractor 11 to easily stabilize its shape during use.

[0063] Modifications of the first embodiment of the present invention will be illustrated using Figures 8 to 10. Unless otherwise specified, the configurations of highly configurable retractors 111 to 115 in these modifications are the same as the configuration of the highly configurable retractor 11 described above.

[0064] First and second modified examples are shown in Figures 8A and 8B, respectively. In the first modified example, the highly configurable retractor 111 has a wavy portion 171a on the lower edge of its central portion 171. This wavy portion 171a may be located on the lower side when the highly configurable retractor 111 is used. Therefore, when the highly configurable retractor 111 is used in an orientation that is upside down from that of Figure 8A, the wavy portion 171a may be located on the edge on the side opposite to that shown in Figure 8A. Furthermore, the highly configurable retractor 111 may have wavy portions 171a on both the upper and lower edges of Figure 8A. In the second modified example of Figure 8B, the highly configurable retractor 112 similarly has a wavy portion 172a on the central portion 172.

[0065] The wavy portions 171a and 172a in the first and second modified examples are wavy in the width direction of the highly configurable retractors 111 and 112. In the highly configurable retractor 112 in the second modified example, the pitch of the wavy portions 172a is longer than the pitch of the wavy portions 171a in the first modified example.

[0066] Third and fourth modified examples are shown in Figures 9A and 9B, respectively. In the third modified example, the central portion 173 of the highly configurable retractor 113 has an uneven portion 173b on the lower edge of the upper and lower edges. This uneven portion 173b may be located on the lower side when the highly configurable retractor 113 is used. Therefore, when the highly configurable retractor 113 is used in an orientation that is upside down from that of Figure 9A, the uneven portion 173b may be located on the edge on the side opposite to that shown in the figure. Furthermore, the highly configurable retractor 113 may have uneven portions 173b on both the upper and lower edges of Figure 9A. In the fourth modified example of Figure 9B, the highly configurable retractor 114 similarly has uneven portions 174b on the central portion 174.

[0067] The uneven portions 173b, 174b in the third and fourth modified examples are uneven in the width direction of the highly shaped retractors 113, 114, respectively. In the highly shaped retractor 114 in the fourth modified example, the pitch of the uneven portions 174b is longer than the pitch of the uneven portions 173b in the third modified example. The corners of each uneven portion 173b, 174b may be rounded to prevent damage to the affected area or its surroundings.

[0068] Because the configurations of the first to fourth modified examples described above allow the highly morphologically stable retractors 111 to 114 to have wavy portions 171a, 172a or uneven portions 173b, 174b on at least one edge, when the highly morphologically stable retractors 111 to 114 are inserted into a wound opening such as that shown in Fig. 4 so that the edge having these wavy portions 171a, 172a or uneven portions 173b, 174b is located at the back, the edge having the wavy portions 171a, 172a or uneven portions 173b, 174b can abut against the affected area or its surroundings at the back. At this time, because the wavy portions 171a, 172a are wavy or the uneven portions 173b, 174b are uneven, the edge having these portions is less likely to slip against the affected area or its surroundings. Therefore, even when the highly shape-stable retractors 111 to 114 configured to form a ring try to expand further outward or contract inward, the resistance force that the wavy portions 171 a, 172 a or the uneven portions 173 b, 174 b receive from the affected area or its surroundings can prevent abrupt expansion or contraction, thereby stabilizing the shape of the highly shape-stable retractors 111 to 114 in a state where they have expanded to a certain extent.

[0069] A fifth modified example is shown in Figures 10A-C. The vertical arrow T in Figures 10B and 10C indicates the thickness direction of the highly configurable retractor 115. Figures 10A and 10B show a front view and a plan view, respectively, of the highly configurable retractor 115 in an unfolded state, and Figure 10C shows a partially enlarged plan view of portion A in Figure 10B. In the unfolded state of the fifth modified example, the highly configurable retractor 115 has a plurality of approximately rectangular quadrilateral portions 175c recessed facing backward on the front surface of the central portion 175. This highly configurable retractor 115 can be assembled, for example, by bending the insertion end 195 backward and then passing the insertion end 195 through the through hole 182 to form a loop. The outer surface in the assembled state has each quadrilateral portion 175c recessed facing radially inward. The partial enlarged plan view of FIG. 10C shows a state in which a quadrilateral portion 175c is recessed in a surface 175d of the central portion 175 in the unfolded state.

[0070] Although not shown, each quadrilateral portion 175c' may be provided in a protruding manner on a surface 175d' of the central portion 175' in the unfolded state, so that each quadrilateral portion 175c' protrudes radially outward in the assembled state.

[0071] With the configuration of the fifth modified example described above, the highly configurable retractor 115 has multiple quadrilateral portions 175c, 175c' on its outer surface when bent. Therefore, when the highly configurable retractor 115 is inserted into a wound, such as that shown in the photographs of Figures 3 or 4, the quadrilateral portions 175c, 175c' can abut against the affected area at the back or surrounding internal organs. Since the quadrilateral portions 175c, 175c' are recessed or protruded on the outer surface, the central portion 175 experiences high friction with these areas, making it less likely to slip. Therefore, even if the highly configurable retractor 115 attempts to expand, rotate, or move, the resistance force exerted by the quadrilateral portions 175c, 175c' from the affected area at the back or surrounding internal organs can prevent this. This stabilizes the shape, posture, or position of the highly configurable retractor 115.

[0072] Note that multiple types of wavy portions 171a, 172a, uneven portions 173b, 174b, and quadrilateral portion 175c illustrated in the first to fifth modified examples may be provided for one highly configurable retractor. For example, wavy portion 171a may be provided on one edge, and wavy portion 172a with a longer pitch may be provided on the other edge. Alternatively, wavy portions 171a, 172a may be provided on one edge, and uneven portions 173b, 174b may be provided on the other edge. Furthermore, quadrilateral portion 175c may be provided on the surface, and wavy portions 171a, 172a or uneven portions 173b, 174b may be provided on the edge.

[0073] [Second Embodiment] A second embodiment of the present invention will be illustrated using Figures 11 to 15. The schematic diagrams of Figures 11A and 11B each show a highly dimensionally stable retractor 21 placed in a region I of a surrounding internal organ or the like, with a retraction portion located above. In Figures 11A and 11B, the arrow U indicates the upper side of the region I of the surrounding internal organ or the like, and the arrow D indicates the lower side. The region I of the surrounding internal organ or the like has, for example, a substantially truncated cone-shaped space that narrows in diameter toward the bottom as shown in Figure 11A, or a substantially truncated cone-shaped space that widens in diameter toward the bottom as shown in Figure 11B. Alternatively, the region I of the surrounding internal organ or the like may have a space that combines a plurality of these substantially truncated cone-shaped spaces, or a space that combines a substantially truncated cone-shaped space with a substantially cylindrical space. In such a case, if the highly configurable retractor 21 in the assembled state forms part of the side surface of an approximately truncated cone, this side surface will fit along the inner surface of the space of area I of the surrounding internal organs, etc., as shown in Figures 11A and 11B, thereby stabilizing the posture of the highly configurable retractor 21. Therefore, the highly configurable retractor 21 can be easily formed into an approximately truncated cone shape in the assembled state as follows.

[0074] FIG. 12A shows the highly shaped-stable retractor 21 in an unfolded state. The left-right arrow L in the figure indicates the longitudinal direction of the highly shaped-stable retractor 21, and the up-down arrow W similarly indicates the width direction. Although not shown in the figure, the highly shaped-stable retractor 21 has a thickness in the depth direction of the figure. A through-hole 22 is formed in the thickness direction near the left end in the longitudinal direction of the highly shaped-stable retractor 21. The highly shaped-stable retractor 21 also has a first locking portion 23 facing upward in FIG. 12A and a second locking portion 24 facing downward near the right end. The portion near the left end is also referred to as the through-hole vicinity 25, and the portion near the right end is also referred to as the locking portion vicinity 26.

[0075] Figure 12B shows a partially enlarged view of the through hole 22. The through hole 22 has a first point 22a, which is a point at the upper left of Figure 12B, and a second point 22b, which is a point at the lower right, on the edge of its inner periphery on the side of the insertion end 28. The first point 22a is located toward one end of the highly dimensionally stable retractor 21 in the width direction, which is located at the top of the figure, and the second point 22b is located toward the other end of the highly dimensionally stable retractor 21 in the width direction, which is located at the bottom. A linear insertion end side edge 22ab of the through hole 22 extends between the first point 22a and the second point 22b. In other words, the straight line segment connecting the first point 22a and the second point 22b follows the insertion end side edge 22ab. These line segments and the insertion end side edge 22ab are inclined so that the first point 22a approaches the left end side in the figure, and the second point 22b approaches the right end side.

[0076] The through hole 22 also has a third point 22c, which is a point at the upper left, and a fourth point 22d, which is a point at the lower right, on the edge of its inner periphery on the insertion end 29 side. The third point 22c is located toward one end of the highly dimensionally stable retractor 21 in the width direction, which is located at the top of the figure, and the third point 22d is located toward the other end of the highly dimensionally stable retractor 21 in the width direction, which is located at the bottom. An insertion end side edge 22cd, which is a linear edge of the through hole 22, extends between the third point 22c and the fourth point 22d. That is, a straight line segment connecting the third point 22c and the fourth point 22d runs along the insertion end side edge 22cd. These line segments and the insertion end side edge 22ab are inclined so that the third point 22c approaches the left edge of the figure, and the fourth point 22d approaches the right edge. The insertion end side edge 22ab and the insertion end side edge 22cd are parallel to each other.

[0077] 13A and 13B show an example of a state in which the insertion end 29 inserted into the through-hole 22 from the front side of the figure advances to the right, similar to FIG. 7 for the first embodiment. That is, after passing through the through-hole 22, the locking portion vicinity 26 overlaps the rear of the through-hole vicinity 25 or the central portion 27 of the adjacent portion. The front side of the figure is the front side of the highly shape-stable retractor 21, and the rear side is the rear side. Furthermore, for clarity, all parts that would normally be shown with hidden lines due to overlapping are shown with solid lines. FIG. 13A shows a state in which the direction of the insertion end side edge 22ab coincides with the width direction of the locking portion vicinity 26 and the central portion 27 of the adjacent portion. The insertion direction is approximately perpendicular to the direction of the insertion end side edge 22ab. Furthermore, because the insertion end side edge 22ab is inclined, the width direction of the through-hole vicinity 25 does not coincide with the width direction of the central portion 27 of the locked portion vicinity 26 and the adjacent portion. The same applies to the insertion end side edge 22cd. This state is called a perpendicular insertion state. FIG. 13B shows a state in which the width direction of the through-hole vicinity 25 coincides with the width direction of the central portion 27 of the locked portion vicinity 26 and the adjacent portion. The insertion direction is inclined relative to the direction of the insertion end side edge 22ab. Furthermore, because the insertion end side edge 22ab is inclined, the direction of the insertion end side edge 22ab does not coincide with the width direction of the central portion 27 of the locked portion vicinity 26 and the adjacent portion. The same applies to the insertion end side edge 22cd. This state is called a diagonal insertion state.

[0078] 13A , the direction of the insertion end side edge 22ab coincides with the width direction of the locked portion vicinity 26 and the central portion 27 of the adjacent portion, and since the through hole width W1, which is the width of the through hole 22 in the direction of the insertion end side edge 22ab, is longer than the normal width W4, the locked portion vicinity 26 and the central portion 27 of the adjacent portion can move in the insertion direction through the through hole 22. In the diagonal insertion state of FIG. 13B , the width direction of the through hole vicinity 25 coincides with the width direction of the locked portion vicinity 26 and the central portion 27 of the adjacent portion, and since the right-angled triangle height W5, which is the length of the through hole 22 in the width direction of the highly dimensionally stable retractor 21, is longer than the normal width W4, the locked portion vicinity 26 and the central portion 27 of the adjacent portion can move in the longitudinal direction of the highly dimensionally stable retractor 21 through the through hole 22. At this time, since the insertion end side edge 22ab is inclined, the through hole width W1 corresponding to the length of the hypotenuse of the right triangle is longer than the right triangle height W5 corresponding to the height of the right triangle.

[0079] 14 shows a state in which the portion 26 adjacent to the locked portion is pulled in the direction opposite to the insertion direction from the perpendicular insertion state shown in FIG. 13A. The portion 26 adjacent to the locked portion is pulled downward and left in the figure. At this time, because the through-hole width W1 is shorter than the maximum width W2, the left end 23a of the first locked portion 23 and the left end 24a of the second locked portion 24 are close to or abut against the insertion end side edge 22ab. Therefore, even in this pulled state, the locked portions 23, 24 are hooked around the periphery of the through-hole 22 and are thereby locked in the insertion direction.

[0080] The other configurations are the same as those of the first embodiment.

[0081] With the above configuration, when the highly shaped retractor 21 is inserted in an oblique direction, the outward surface forms the side of a substantially disk having a center line in the up-down direction. Furthermore, when the highly shaped retractor 21 is inserted in an orthogonal direction, the extensions of the generatrices at different positions in the length direction intersect or approach each other below the highly shaped retractor 21, so that the outward surface forms part of the side of a substantially truncated cone having a center line in the up-down direction and tapering downward. In this way, when the outward surface of the highly shaped retractor 21 forms part of the side of a substantially truncated cone, this surface can follow the shape of part or all of the space of the surrounding internal organs or other parts.

[0082] For example, if the through-hole width W1, which is the length of the through-hole 22 in the inclined direction of the insertion end side edge 22ab, is not significantly larger than the normal width W4, the portion 26 adjacent to the locking portion and the central portion 27 adjacent thereto are less likely to get caught around the through-hole 22 and easier to pass through when passing through the through-hole 22 in a direction perpendicular to the inclined direction in the orthogonal insertion state than when passing through the through-hole 22 in a direction not perpendicular to the inclined direction in the diagonal insertion state. This is because the through-hole width W1 is longer than the right-angled triangle height W5. Therefore, by inclining the insertion end side edge 22ab, the highly morphologically stable retractor 21 can change the insertion depth and slightly change the diameter while the outward surface in the orthogonal insertion state forms part of the side of a roughly truncated cone. As a result, the outward surface can more easily conform to the shape of part or all of the space of the surrounding internal organs, etc., and the retractor fits well in the expanded state after insertion into the retraction.

[0083] In either the orthogonal insertion state or the oblique insertion state, when the slit width Wa, which is the width of the through hole 22 in the direction perpendicular to the inserted end side edge 22ab, is shorter than a certain width, the locked portion vicinity 26 and the central portion 27 of the portion adjacent thereto are more likely to get caught around the through hole 22 and are more difficult to pass through. This is because, even though the locked portion vicinity 26 is inserted at a shallow angle relative to the periphery of the through hole 22 when viewed in the planar direction of the highly shape-stable retractor 21, the friction caused by contact between the through hole vicinity 25 and the locked portion vicinity 26 increases by the amount of slit width Wa.

[0084] 14 , the first and second locked portions 23 and 24 approach or abut the insertion end side edge 22ab of the through-hole 22, and the locked portion vicinity 26 is locked in the insertion direction by the through-hole vicinity 25. The left end 23a of the first locked portion and the left end 24a of the second locked portion are positioned on a straight line in the width direction of the highly shape-stable retractor 21. Therefore, when the locked portion vicinity 26 is pulled in the opposite direction to the insertion direction, the through-hole vicinity 25 can be locked with the first and second locked portions 23 and 24 with equal force. This allows the highly shaped retractor 21 to maintain a state in which the portion 26 adjacent to the locked portion is locked in the insertion direction while maintaining a constant, approximately truncated cone shape.The highly shaped retractor 21 can then continue to be assembled in a stable form.

[0085] A modified example of the second embodiment of the present invention will be illustrated using Fig. 15. Unless otherwise specified, the configuration of a highly configurable retractor 211 in this modified example is the same as the configuration of the highly configurable retractor 21 described above.

[0086] The through-hole 221 of the highly shaped retractor 211 is inclined in the opposite direction relative to the longitudinal direction as compared to the highly shaped retractor 21. That is, the insertion end side edge 221ab is inclined so that the first point 221a approaches the right end of the figure and the second point 221b approaches the left end of the figure. Also, the insertion end side edge 221cd is inclined so that the third point 221c approaches the right end of the figure and the fourth point 221d approaches the left end of the figure.

[0087] With this configuration, when the highly shaped-stability retractor 211 is inserted in an orthogonal direction, the extension lines of the generatrices at different positions in the lengthwise direction intersect or approach each other above the highly shaped-stability retractor 211, and the outward surface forms part of the side of an approximately truncated cone having a center line in the approximately vertical direction and a diameter that decreases toward the top.

[0088] In the highly configurable retractors 21, 211 exemplified in this embodiment, the state in which the insertion end 29, 291 is inserted into the through hole 22, 221 may only be the orthogonal insertion state. However, in this case, the outward surface always forms part of the side surface of a substantially truncated cone. That is, although the through hole width W1 is larger than the normal width W4, the right-angled triangle height W5 is the same length or shorter, so it is not possible to achieve the oblique insertion state in which the width direction of the through hole vicinity 25, 251 and the width direction of the locking portion vicinity 26, 261 are aligned. Therefore, the highly configurable retractors 21, 211 cannot form a disk-like side surface.

[0089] [Third Embodiment] A third embodiment of the present invention will be illustrated using Figures 16 to 19. Figure 16 shows a highly shaped retractor 31 in an unfolded state. The highly shaped retractor 31 has a through-hole 32 in the thickness direction formed in a portion near the left end in the longitudinal direction. The highly shaped retractor 31 also has a first locked portion 33 facing upward in the figure and a second locked portion 34 facing downward in the same portion near the right end. The portion near the left end will also be referred to as a through-hole vicinity 35, and the portion near the right end will also be referred to as a locked portion vicinity 36.

[0090] Figure 17 shows a partially enlarged view of the through hole 32. The through hole 32 has a first point 32a, which is a point at the upper left of Figure 17, and a second point 32b, which is a point at the lower right, on the inner periphery of the through hole 32 on the side of the insertion end 38. The first point 32a is located toward one end of the highly dimensionally stable retractor 31 in the width direction, which is located at the top of the figure, and the second point 32b is located toward the other end of the highly dimensionally stable retractor 31 in the width direction, which is located at the bottom. A linear insertion end side edge 32ab of the through hole 32 extends between the first point 32a and the second point 32b. In other words, a straight line segment connecting the first point 32a and the second point 32b follows the insertion end side edge 32ab. These line segments and the insertion end side edge 32ab are inclined so that the first point 32a approaches the left end of the figure and the second point 32b approaches the right end. W5 is the same length as the height of the right triangle in the second embodiment, and is also called the right triangle height as in the second embodiment.

[0091] 18 shows an example of a state in which, in the assembled state of the highly configurable retractor 31, the insertion end 39 inserted into the through-hole 32 from the front of the highly configurable retractor 31 (the back side of the figure) advances toward the right of the highly configurable retractor 31 (the left side of the figure). This figure is a tracing of an image of a transparent model created for ease of understanding. The highly configurable retractor 31 in this figure is in an orthogonal insertion state. Furthermore, by changing the insertion direction so that the width direction of the through-hole vicinity 35 coincides with the width direction of the locking portion vicinity 36 and the central portion 37 of the adjacent portion, the highly configurable retractor 31 in the assembled state can be changed to an oblique insertion state. In the highly shape-stable retractor 31, when inserted in the orthogonal direction, extensions of the generatrices at different positions in the length direction intersect or approach each other below the highly shape-stable retractor 31, and the outward surface forms part of the side of a substantially truncated cone having a center line in the substantially vertical direction and a diameter that decreases toward the bottom. Figure 18 shows this configuration. In addition, when inserted in the oblique direction, the outward surface forms the side of a substantially disk having a center line in the vertical direction.

[0092] In addition, the second through-hole width W6, which is the width of the insertion end side edge 32cd located immediately to the right of the insertion end side edge 32ad of the through-hole 32 in Figure 17, is shorter than the through-hole width W1, shorter than the normal width W4, and shorter than the right-angled triangle height W5.

[0093] The other configurations are the same as those of the second embodiment.

[0094] 18 , the direction of the insertion end side edge 32ab is approximately aligned with the width direction of the locked portion vicinity 36 and the central portion 37 of the adjacent portion, and since the through hole width W1, which is the width of the through hole 32 in the direction of the insertion end side edge 32ab, is longer than the normal width W4, the locked portion vicinity 36 and the central portion 37 of the adjacent portion can move in the insertion direction through the through hole 32. Although not shown, in the oblique insertion state, the width direction of the through hole vicinity 35 is aligned with the width direction of the locked portion vicinity 36 and the central portion 37 of the adjacent portion, and since the right-angled triangle height W5, which is the length of the through hole 32 in the width direction of the highly dimensionally stable retractor 31, is longer than the normal width W4, the locked portion vicinity 36 and the central portion 37 of the adjacent portion can move in the longitudinal direction of the highly dimensionally stable retractor 31 through the through hole 32. At this time, the width W1 of the through hole is longer than the height W5 of the right triangle because the insertion end side edge 32ab is inclined.

[0095] For example, if the through-hole width W1 is not significantly larger than the normal width W4, the portion 36 adjacent to the interlocking portion and the central portion 37 adjacent thereto are less likely to get caught around the through-hole 32 and are easier to pass through when passing through the through-hole 32 in a direction perpendicular to the inclination direction in the orthogonal insertion state than when passing through the through-hole 32 in a direction not perpendicular to the inclination direction in the diagonal insertion state. This is because the through-hole width W1 is longer than the right-angled triangle height W5. Therefore, by inclining the insertion end side edge 32ab, the highly morphologically stable retractor 31 can change the insertion depth and minutely change the diameter while the outward surface in the orthogonal insertion state remains in the shape of a part of the side surface of a substantially truncated cone. As a result, the outward surface can more easily conform to the shape of part or all of the space of the surrounding internal organs, etc., and the retractor fits well after insertion into the retraction.

[0096] 19 shows a state in which the locked portion neighboring portion 36 is pulled in the direction opposite to the insertion direction from the perpendicular insertion state shown in FIG. 18 . The locked portion neighboring portion 36 is pulled downward and left in the figure. At this time, because the through-hole width W1 is shorter than the maximum width W2, the first locked portion left end 33a of the first locked portion 33 and the second locked portion left end 34a of the second locked portion 34 approach or abut the insertion end side edge 32ab. Therefore, even in this pulled state, the locked portions 33, 34 are hooked around the periphery of the through-hole 32 and are locked in the insertion direction. As a result, the locked portion neighboring portion 36 is locked in the insertion direction by the through-hole neighboring portion 25.

[0097] The left end 33a of the first locked portion and the left end 34a of the second locked portion are positioned on a straight line in the width direction of the highly configurable retractor 31. Therefore, when the locked portion vicinity 36 is pulled in the direction opposite to the insertion direction, the through-hole vicinity 35 can be locked with equal force to the first locked portion 33 and the second locked portion 34. This allows the highly configurable retractor 31 to maintain a state in which the locked portion vicinity 36 is locked in the insertion direction while maintaining a constant, approximately truncated cone shape. Thus, the highly configurable retractor 31 can continue to be assembled in a stable form.

[0098] In the highly configurable retractor 31 exemplified in this embodiment, the state in which the insertion end 39 is inserted into the through hole 32 may be only the orthogonal insertion state. However, in this case, the outward surface always forms part of the side surface of a substantially truncated cone. That is, although the through hole width W1 is larger than the normal width W4, the right-angled triangle height W5 is the same length or shorter, so it is not possible to achieve an oblique insertion state in which the width direction of the through hole vicinity 35 and the width direction of the locked portion vicinity 36 are aligned. Therefore, the highly configurable retractor 31 cannot form a disk-like side surface.

[0099] [Fourth Embodiment] A fourth embodiment of the present invention will be illustrated using Figures 20 to 23. Figure 20 shows a highly shaped retractor 41 in an unfolded state. The highly shaped retractor 41 has a through-hole 42 in the thickness direction formed in a portion near the left end in the longitudinal direction. The highly shaped retractor 41 also has a first locked portion 43 facing upward in the figure and a second locked portion 44 facing downward in the same portion near the right end. The portion near the left end will also be referred to as a through-hole vicinity 45, and the portion near the right end will also be referred to as a locked portion vicinity 46.

[0100] Figure 21 shows a partially enlarged view of the through hole 42. The through hole 42 has a first point 42c, which is a point at the upper left of Figure 21, and a second point 42d, which is a point at the lower right, on the edge of the inner periphery on the insertion end 49 side, which is the right side in Figure 20. The first point 42c is located toward one end of the highly dimensionally stable retractor 41 in the width direction, which is located at the top of the figure, and the second point 42d is located toward the other end of the highly dimensionally stable retractor 41 in the width direction, which is located at the bottom. A linear insertion end side edge 42cd of the through hole 42 extends between the first point 42c and the second point 42d. In other words, the straight line segment connecting the first point 42c and the second point 42d runs along the insertion end side edge 42cd. These line segments and the insertion end edge 42cd are inclined so that the first point 42c approaches the left end of the figure and the second point 42d approaches the right end. W5 is the same length as the height of the right triangle in the second and third embodiments, and is also referred to as the right triangle height as in the second embodiment. Furthermore, the insertion end edge 42ab, located to the left of the insertion end edge 42cd in Figure 21, is formed in a substantially straight line in the width direction of the highly shape-stable retractor 41.

[0101] FIG. 22 shows an example of the assembled state of the highly configurable retractor 41, in which the insertion end 49 inserted into the through-hole 42 from the front of the highly configurable retractor 41 (the far side of the figure) advances to the right of the highly configurable retractor 41 (the left side of the figure). This figure is a tracing of an image of a transparent model created for ease of understanding. The insertion direction is approximately perpendicular to the direction of the insertion end side edge 42cd. The state of the highly configurable retractor 41 in this figure is called the perpendicular insertion state. Furthermore, the insertion direction can be changed so that the width direction of the through-hole vicinity 45 coincides with the width direction of the locking portion vicinity 46 and the central portion 47 adjacent thereto. This state is called the oblique insertion state, as in the second and third embodiments. In the highly shape-stable retractor 41, when inserted in the orthogonal direction, extensions of the generatrices at different positions in the length direction intersect or approach each other below the highly shape-stable retractor 41, and the outward surface forms part of the side of a substantially truncated cone having a center line in the substantially vertical direction and a diameter that decreases toward the bottom. Figure 22 shows this shape. In addition, when inserted in the oblique direction, the outward surface forms the side of a substantially disk having a center line in the vertical direction.

[0102] The second through-hole width W6, which is the width of the insertion end side edge 42ab, is shorter than the through-hole width W1, shorter than the normal width W4, and shorter than the right-angled triangle height W5.

[0103] The other configurations are the same as those of the third embodiment.

[0104] 22 , the direction of the insertion end side edge 42cd is approximately aligned with the width direction of the locked portion vicinity 46 and the central portion 47 of the adjacent portion, and since the through hole width W1, which is the width of the through hole 42 in the direction of the insertion end side edge 42cd, is longer than the normal width W4, the locked portion vicinity 46 and the central portion 47 of the adjacent portion can move in the insertion direction through the through hole 42. Although not shown, in the oblique insertion state, the width direction of the through hole vicinity 45 is aligned with the width direction of the locked portion vicinity 46 and the central portion 47 of the adjacent portion, and since the right-angled triangle height W5, which is the length of the through hole 42 in the width direction of the highly dimensionally stable retractor 41, is longer than the normal width W4, the locked portion vicinity 46 and the central portion 47 of the adjacent portion can move in the longitudinal direction of the highly dimensionally stable retractor 41 through the through hole 42. At this time, the width W1 of the through hole is longer than the height W5 of the right triangle due to the inclination of the insertion end side edge 42cd.

[0105] For example, if the through-hole width W1 is not significantly larger than the normal width W4, the portion 46 adjacent to the interlocking portion and the central portion 47 adjacent thereto are less likely to get caught around the through-hole 42 when passing through the through-hole 42 in a direction perpendicular to the inclination direction in the orthogonal insertion state than when passing through the through-hole 42 in a direction not perpendicular to the inclination direction in the diagonal insertion state. This is because the through-hole width W1 is longer than the right-angled triangle height W5. Therefore, by inclining the insertion end side edge 42cd, the highly morphologically stable retractor 41 can change the insertion depth and minutely change the diameter while the outward surface in the orthogonal insertion state remains in the shape of a part of the side surface of a substantially truncated cone. As a result, the outward surface can more easily conform to the shape of part or all of the space of the surrounding internal organs, etc., and fits well after insertion into the retraction.

[0106] 23 shows a state in which the locking portion vicinity 46 is pulled in the direction opposite to the insertion direction from the perpendicular insertion state shown in FIG. 22. By pulling, the locking portion vicinity 46 of the assembled highly dimensionally stable retractor 41 rotates in the clockwise direction CL in the figure relative to the through-hole vicinity 45, and the width direction of the locking portion vicinity 46 coincides with the width direction of the through-hole vicinity 45, changing to a diagonal insertion state. The locking portion vicinity 46 is pulled leftward in the figure. That is, because the second through-hole width W6 is shorter than the maximum width W2, the first locking portion left end 43a of the first locking portion 43 and the second locking portion left end 44a of the second locking portion 44 approach or abut the insertion end side edge 42ab. When the second locked portion 44 approaches or abuts against the insertion end side edge 42ab, the locked portion neighboring portion 46 stops the rotation in the clockwise direction CL. Even in this pulled state, the locked portions 43, 44 are caught around the through-hole 42 and locked in the right direction, and as a result, the locked portion neighboring portion 46 is locked in the right direction by the through-hole neighboring portion 45.

[0107] The left end 43a of the first locked portion and the left end 44a of the second locked portion are positioned on a straight line in the width direction of the highly configurable retractor 41. Therefore, after the locked portion vicinity 46 stops rotating in the clockwise direction CL, the through-hole vicinity 45 can be locked with equal force to the first locked portion 43 and the second locked portion 44. This allows the highly configurable retractor 41 to maintain a state in which the locked portion vicinity 46 is locked facing rightward while maintaining a constant, approximately truncated cone shape. Thus, the highly configurable retractor 41 can continue to be assembled in a stable form.

[0108] The highly configurable retractor 41 illustrated in this embodiment may be inserted into the through-hole 42 only in the orthogonal insertion state, except for the state in which it is pulled left and right as shown in Figure 23. However, in this case, the outward surface always forms part of the side surface of a substantially truncated cone. That is, although the through-hole width W1 is larger than the normal width W4, the right-angled triangle height W5 is the same length or shorter, so it is not possible to achieve an oblique insertion state in which the width direction of the through-hole vicinity 45 and the width direction of the locked portion vicinity 46 are aligned. Therefore, the highly configurable retractor 41 cannot form a disk-like side surface.

[0109] [Fifth embodiment] A first embodiment of the present invention will be illustrated using Figures 24 and 25. In Figure 24, 51 is a highly configurable retractor. The highly configurable retractor 51 of the present invention is an arc-shaped thin plate that has a width when unfolded into a plate shape as shown in Figure 24. Arrow CI shown in Figure 24 points in the circumferential direction of the highly configurable retractor 51, and arrow W also points in the width direction. Although not shown in Figure 24, the highly configurable retractor 51 has a thickness that is in the depth direction of the figure.

[0110] In its unfolded state, the highly dimensionally stable retractor 51 has a first end, which is one end in the circumferential direction, and a second end, which is the other end spaced apart from the first end. The first end is located on the left side of the figure, and the second end is located on the right side of the figure. A through-hole 52 is formed in the thickness direction near the first end. A pair of engaging portions 53, 54 is provided near the second end. Each engaging portion 53, 54 is provided so as to protrude outward in both width directions of the highly dimensionally stable retractor 51. Of the pair of engaging portions 53, 54, the first engaging portion 53 is provided facing upward and to the right in FIG. 1, and the second engaging portion 54 is provided facing downward and to the left in FIG. The first end is also referred to as an insertion end 58, and the second end is also referred to as an insertion end 59, which will be described below. Furthermore, the portion near the first end is also simply referred to as the portion near the first end or the through-hole portion 55 , and the portion near the second end is also simply referred to as the portion near the second end or the locked portion portion 56 .

[0111] The central portion that is sandwiched between the through-hole vicinity portion 55 and the locked portion vicinity portion 56 in the circumferential direction is called the central portion 57. When the highly shape-stable retractor 51 is in an unfolded state, the central portion 57 has a width and extends in an arc shape centered on a center point C. The central portion 57 has a center line CL located in the center in the width direction, and this center line CL forms an arc centered on the center point C. Both ends 57a, 57b of the central portion 57 in the width direction also describe arcs centered on the center point C. A normal width W4, which is the distance between the outer end 57a, which is the outer end in the width direction, and the inner end 57b, which is the inner end, of the central portion 57, is slightly shorter than the through width W1, which is the width of the through hole 52 in the width direction.

[0112] The portion 56 adjacent to the locked portion has a narrowed portion 60 recessed inward in the width direction. The narrowed portion 60 is located adjacent to the first locked portion 53 and closer to the central portion 57.

[0113] The highly configurable retractor 51 can be elastically curved from a plate state, with the insertion end 58 and the insertion end 59 overlapping in the thickness direction of the plate state and curling to form a loop. Figure 25A is a perspective view of the through-hole vicinity 55 from diagonally above, showing the state in which the insertion end 59 has been curved from the arc-shaped state shown in Figure 24 so that it is turned backward and then passed through the through-hole 52 from the front. As shown in this figure, the insertion end 59 is passed through the through-hole 52 from the outside of the loop toward the inside. Figure 25B is a front view with the through-hole vicinity 55 facing forward. The state shown in these figures is referred to as the assembled state. The arrow U indicates the upward direction of the highly configurable retractor 51 in the assembled state in each figure, and the arrow D indicates the downward direction in each figure. The arrow L indicates the leftward direction in each figure, and the arrow R indicates the rightward direction in each figure. The arrow F indicates the front in each figure, and the arrow B indicates the rear in each figure. The outward surface of the highly configurable retractor 51 in the assembled state forms the side of a generally truncated cone whose diameter increases toward the top. However, the arrows U, D, L, R, F, and B do not necessarily indicate the upper, lower, left, right, front, and rear directions, respectively, when the highly configurable retractor 51 is in use. Furthermore, the highly configurable retractor 51 may be assembled not only by bending the insertion end 59 backward as shown in FIG. 2, but also by bending the insertion end 59 from the front, in which case the assembled state is shown reversed left and right. In this way, the highly configurable retractor 51 can be used in the upper, lower, left, right, front, or rear direction, depending on the user's convenience, and can also be assembled and used with either the front or back side facing outward.

[0114] The other configurations are the same as those of the first embodiment.

[0115] With the above configuration, the center line CL describes an arc, so the highly dimensionally stable retractor 51 forms a curved shape by curving from a plate state to form a loop, and the outward surface forms the side surface of a substantially truncated cone. The inward surface forms the back surface of this side surface. At this time, the inner half of the arc-shaped center line CL forms a curved surface that slopes to form the reduced-diameter half of the substantially truncated cone. This reduced-diameter half of the side surface is the lower half of FIG. 25B and is indicated by reference numeral 51s in this figure. This reduced-diameter half of the side surface is referred to as the reduced-diameter side side surface 51s. Similarly, the outer half of the center line forms a curved surface that slopes to form the expanded-diameter half of the substantially truncated cone. This expanded-diameter half of the side surface is the upper half of FIG. 25B and is indicated by reference numeral 51e in this figure. This expanded-diameter half of the side surface is referred to as the expanded-diameter side side surface 51e.

[0116] As a result, the highly shape-stable retractor 51 in the assembled state has an outward surface that can easily conform to the shape of part or all of the space of the surrounding internal organs, etc., and fits well after being inserted into the retraction area.

[0117] Furthermore, because the outer end 57a is widened in the assembled state, there is little risk of an instrument coming into contact with the outer end 57a when the instrument is brought into contact with the affected area through the opening on the widened diameter side of the highly configurable retractor 51. Therefore, there is little possibility that the instrument will damage the highly configurable retractor 51. This is also effective in the case of robotic surgery.

[0118] 26 to 28 illustrate a sixth embodiment of the present invention. In FIG. 26, reference numeral 61 denotes a highly configurable retractor. In the unfolded state as shown in FIG. 26, the highly configurable retractor 61 has an insertion end 68 and an insertion end 69. A through hole 62 is formed in a through hole vicinity 65, which is the portion near the insertion end 68. A pair of locked portions 63, 64 is provided in a locked portion vicinity 66, which is the portion near the insertion end 69. The locked portions 63, 64 are provided so as to protrude outward in both directions in the width direction of the highly configurable retractor 61.

[0119] A normal width W4, which is the distance between the outer end 67a and the inner end 67b of the central portion 67, is slightly shorter than a right-angled triangle height W5, which is the length of the through-hole 62 in the width direction.

[0120] The locked portion neighboring portion 66 has a narrowed portion 70 recessed inward in the width direction. The narrowed portion 70 is located adjacent to the first locked portion 63 and closer to the central portion 67.

[0121] Figure 27 is a partially enlarged view of the vicinity of the through-hole vicinity 65 of the highly shaped retractor 61. The through-hole 62 has a first point 62a, which is a point at the upper left of Figure 27, and a second point 62b, which is a point at the lower right, on the edge of its inner periphery on the side of the insertion end 68. The first point 62a is located toward the outside of the center line CL of the highly shaped retractor 61, and the second point 62b is located toward the inside. A linear insertion-end-side edge 62ab of the through-hole 62 extends between the first point 62a and the second point 62b. That is, a straight line segment connecting the first point 62a and the second point 62b follows the insertion-end-side edge 62ab. As shown in FIG. 27, an inward extension line 62ab' extends from the line segment connecting the first point 62a and the second point 62b, and is an extension of this line segment and extends inward of the arc.

[0122] The inward extension line 62ab' passes through an intersection point CRab that is farther from the center point C with respect to the arc of the center line CL.

[0123] The through hole 62 also has a third point 62c, which is a point at the upper left in FIG. 27 , and a fourth point 62d, which is a point at the lower right, on the inner periphery of the insertion end 69 side. The third point 62c is located outboard of the center line CL of the highly dimensionally stable retractor 61, and the fourth point 62d is located inboard. An insertion end side edge 62cd, which is a linear edge of the through hole 62, extends between the third point 62c and the fourth point 62d. That is, a line segment connecting the third point 62c and the fourth point 62d runs along the insertion end side edge 62cd. As shown in FIG. 27 , an inward extension line 62cd′ extends from the line segment connecting the third point 62c and the fourth point 62d, which is an inward extension of the arc. This inward extension line 62cd' also passes through the intersection point CRcd, which is located farther from the center point C with respect to the arc of the center line CL.

[0124] As described above, the through-hole 62 has a line segment along the insertion end side edge 62 ab and a line segment along the insertion end side edge 62 cd that are both inclined with respect to the width direction of the highly shape-stable retractor 61 .

[0125] The highly dimensionally stable retractor 61 can be elastically curved from a plate state, with the insertion end 68 side and the insertion end 69 side overlapping in the thickness direction of the plate state and curling up to form a ring. Fig. 28A is a perspective view of the insertion end 69 curved from the arc-shaped state shown in Figs. 26 and 27 so that the insertion end 69 is turned to the back side and then passed through the through hole 62 from the front, as viewed obliquely from above the through hole vicinity 65. Fig. 28B is a front view of the through hole vicinity 65 as viewed from the front.

[0126] The other configurations are the same as those of the fifth embodiment.

[0127] With the above configuration, the center line CL describes an arc, so that the highly shape-stable retractor 61 forms a curved shape by curving from a plate state to form a loop, and the outward surface forms the side surface of an approximately truncated cone. The inward surface forms the back surface of this side surface. The side surface on the reduced diameter side is called the reduced diameter side surface 61s, and the side surface on the expanded diameter side is called the expanded diameter side surface 61e.

[0128] [Example] An example of the fifth embodiment will be described with reference to Figure 29. The inventors produced a highly dimensionally stable retractor 51 according to the fifth embodiment by cutting out a 0.4 mm thick polyether ether ketone resin plate according to the development view shown in Figure 24. The center line CL of this prototype, prototype T51, had a radius of 84 mm and an arc length of 192.3 mm, which was the length of the arc of the center line CL. The width of the central portion 57 was 16.0 mm. The length of the oval through-hole 52 was 16.4 mm.

[0129] Figure 29A, like Figure 25A, is a traced image of the prototype T51 when the insertion end T59 is bent so as to turn backward and then passed through the through hole T52 from the front, as viewed obliquely from above the through hole vicinity T55. Figure 29B is a traced image of the prototype T51 when the insertion end T59 is further inserted from the state of Figure 29A and has advanced approximately half a turn beyond the through hole T52, as viewed obliquely from above. Figure 29C is a traced image of the prototype T51 when viewed from the front, as viewed from above, as viewed from above the through hole vicinity T55. As can be seen from these figures, the prototype T51 is curved from a plate state to form a ring, forming a curved shape, with the outward surface forming the side surface of an approximately truncated cone and the inward surface forming the back surface of this side surface.

[0130] On the other hand, by turning the insertion end T59 in this manner, the inventors discovered that because the center line CL of the prototype T51 describes an arc, the elastic force generated when the prototype T51 curves from a plate shape to form a loop tends to cause the three-dimensional shape after winding to become spiral. Although not shown in the figure, if the insertion end T59 were not passed through the through hole T52, the portion near the inserted end T58 and the portion near the insertion end T59 would be misaligned in the vertical direction after winding, which would tend to result in a spiral shape.

[0131] We found that when the inserting end T59 of such a prototype T51 was passed through the through hole T52, the portion near the inserting end T59 tended to protrude upward in the figure, toward the expanded diameter side of the truncated cone, resulting in a failure to align with the portion near the inserted end T58 of the previous turn. This tendency was particularly pronounced when winding proceeded as shown in Figures 29B and 29C. In such cases, for example, the outer end T57a gradually shifted upward as winding proceeded. Thus, we found that a force was applied to the prototype T51 that biased the inserting end T59 toward the expanded diameter side of the truncated cone, and that under this condition, the outward surface of the prototype T51 sometimes formed a distorted truncated cone.

[0132] Next, an example of the sixth embodiment will be described with reference to Figure 30. The inventors produced a highly dimensionally stable retractor 61 according to the sixth embodiment by cutting out a 0.4 mm thick polyether ether ketone resin plate according to the development diagram shown in Figure 26. The center line CL of this prototype, prototype T61, had a radius of 84 mm and an arc length of 192.3 mm, which was the length of the arc of the center line CL. The width of the central portion 67 was 16.0 mm. The oval through-hole 62 was 16.4 mm long, and the angle between the length and the width was 20°.

[0133] 30A and 30B are traced images of the prototype T61 viewed from diagonally above the through-hole vicinity T65, similar to FIGS. 29A and 29B. Also, FIG. 30C is a traced image of the front view of the through-hole vicinity T65, similar to FIG. 29C. As can be seen from these figures, the prototype T61, like the prototype T51, forms a curved shape by curving from a plate state to form a ring, with the outward surface forming the side of a roughly truncated cone and the inward surface forming the back surface of this side.

[0134] Furthermore, when the prototype T61 is unfolded, the through hole T62 of the prototype T61 is inclined so that the extension lines of the line segment connecting the first point 62a and the second point 62b and the line segment connecting the third point 62c and the fourth point 62d, extending inward from the arc, pass at a position farther from the arc than the center line C of the arc. Therefore, it was found that the insertion end T69, having made a full circle and passed through the through hole 62, tends to move toward the narrowing side of the truncated cone, which is in a direction perpendicular to the inclination direction, rather than along the arc. In other words, it was found that the insertion end T69 easily passes through the through hole T62 when passing in a direction perpendicular to the inclination direction, but that it easily gets caught around the through hole T62 when passing in a direction not perpendicular to the inclination direction, making it difficult to pass through the through hole T62. Therefore, it was found that in prototype T61, a force was applied that biased the insertion end T69 toward the narrowed diameter side of the truncated cone, which was easier to pass through.

[0135] As shown above, in the prototype T61, because the center line CL forms an arc and the through hole T62 is inclined in the unfolded state, a state was found in which the force tending to bias the insertion end T69 toward the enlarged diameter side of the truncated cone and the force tending to bias it toward the reduced diameter side were balanced. As a result, as shown in Figures 30B and 30C, even as winding progressed, the insertion end T69 rarely shifted toward either the enlarged diameter side or the reduced diameter side, and the outward surface of the prototype T61 formed a distortion-free truncated cone surface. Furthermore, the inward surface formed a distortion-free reverse surface of the truncated cone surface. As shown in Figures 30B and 30C, there was almost no gradual upward displacement of the outer end T67a. Therefore, the outward surface can easily conform to the shape of part or all of the space of the surrounding internal organs, etc., and fits well after insertion into the wound.

[0136] Furthermore, since the outer end T67a is less likely to shift upward, it is possible to reduce the possibility that an instrument being delivered to an affected area will get caught on the outer end T67a, which is also effective in the case of robotic surgery.

[0137] Although the embodiments of the present invention have been described above as examples, the present invention is not limited to these embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0138] For example, although the insertion end is shown to be inserted through the through-hole from the outside to the inside of the ring, the insertion end may be inserted from the inside to the outside of the ring as long as the area near the locked portion does not protrude significantly outward from the ring in the assembled state. In other words, the area near the through-hole and the area near the locked portion may overlap in the reverse order.

[0139] Furthermore, although each figure shows a configuration in which the constricted portions are recessed downward in the width direction, these constricted portions may also be recessed upward in the width direction. Furthermore, when the highly configurable retractor such as the fifth and sixth embodiments is formed in an arc shape, the constricted portion may be recessed adjacent to the center of the second engaging portion, as shown in the example of Figure 31 . Furthermore, two constricted portions may be recessed on both sides in the width direction. As described above, the highly configurable retractor of the present invention is used in a direction that is convenient for the user, such as upward, downward, left, right, forward, or backward, and it is sufficient for the constricted portions to be provided in such a convenient direction.

[0140] The resin component may be any resin other than polyether ether ketone resin or polyphenylene sulfide resin, as long as it has chemical resistance.

[0141] Furthermore, an example of an approximately rectangular quadrilateral portion has been given for the fifth modified example of the first embodiment, but when such a quadrilateral portion is applied to the highly shaped retractor according to the fifth or sixth embodiment, an approximately trapezoidal quadrilateral portion may be provided instead of the approximately rectangular quadrilateral portion, in accordance with the fact that the highly shaped retractor according to the fifth or sixth embodiment is formed in an arc shape having a width.

[0142] Furthermore, although an example has been given in which the left ends of the first and second locked portions are positioned on a straight line in the width direction of the highly dimensionally stable retractor, the left ends do not have to be positioned on a straight line as long as the orientation of these adjacent portions is the intended orientation when the portions adjacent to the locked portions are locked by the portions adjacent to the through-hole in the direction in which the loop is to be compressed.Then, by positioning the left ends in a position other than on a straight line, the loop may be expanded in an orientation of the adjacent portions other than that shown in the example.

[0143] The present invention can be used in a retractor for holding an incision site of a human body open.

[0144] 11, 21, 31, 41, 51, 61, 111, 112, 113, 114, 115, 211 Highly shaped-stable retractor 12, 22, 32, 42, 52, 62, 125, 221 Through hole 13, 23, 33, 43, 53, 63 First engaged portion 13a, 23a, 33a, 43a Left end of first engaged portion 14, 24, 34, 44, 54, 64 Second engaged portion 14a, 24a, 34a, 44a Left end of second engaged portion 15, 25, 35, 45, 55, 65, 251 Portion near through hole (portion near first end) 16, 26, 36, 46, 56, 66, 261 Portion near engaged portion (portion near second end) 17, 27, 37, 47, 57, 67, 171, 172, 173, 174, 175 Central portion 18, 28, 38, 48, 58, 68, 185, 281 Inserted end (first end) 19, 29, 39, 49, 59, 69, 195, 291 Inserted end (second end) 20, 30, 40, 50, 60, 70 Narrowed portion 22a, 32a, 42c, 62a, 221a First point 22b, 32b, 42d, 62b, 221b Second point 22ab, 32ab, 42ab, 62ab, 221ab Inserted end side edge 22c, 62c, 221c Third point 22d, 62d, 221d Fourth point 22cd, 32cd, 42cd, 62cd, 221cd Insertion end side edge 51e, 61e Enlarged diameter side surface 51s, 61s Reduced diameter side surface W1 Through hole width W2 Maximum width W3 Minimum width W4 Normal width W5 Right triangle height W6 Second through hole width

Claims

1. A highly dimensionally stable retractor characterized in that it contains a synthetic resin that is chemical-resistant and elastic as its main resin component, has a first end and a second end spaced apart from the first end and has a width direction when unfolded into a plate, and is configured to bend elastically from the plate state so that the first end and the second end overlap in the thickness direction of the plate state to form a ring, has a through-hole in the portion near the first end that is near the first end, through which the second end can be passed, and the diameter of the ring can be changed by changing the length of the passage of the second end through the through-hole.

2. A highly dimensionally stable retractor as described in claim 1, characterized in that the portion near the second end, which is near the second end, has an engaging portion that protrudes in the width direction beyond the through hole when the second end is passed through the portion near the first end.

3. A highly dimensionally stable retractor as described in claim 2, characterized in that it has a pair of the engaging portions, each of which protrudes outward in both directions in the width direction, and at least the engaging portion provided on one side in the width direction is formed so as to protrude from a constricted portion that is adjacent to the direction approaching the first end and is recessed inward in the width direction.

4. A highly dimensionally stable retractor as claimed in any one of claims 1 to 3, characterized in that the inner peripheral edge of the through hole has a shape having a line segment between two points, and the line segment between the two points is inclined so that of these two points, the first point located closer to the first edge in the width direction is closer to either the first end or the second end than the second point located closer to the second edge in the width direction.

5. A highly dimensionally stable retractor as claimed in any one of claims 1 to 3, characterized in that in the central portion sandwiched between the portion near the first end and the portion near the second end, the center line in the width direction forms an arc in the unfolded state.

6. A highly dimensionally stable retractor as described in claim 5, characterized in that the inner peripheral edge of the through hole has a shape having a line segment between two points, and in the unfolded state, the line segment between the two points is inclined with respect to the width direction so that an extension line of the line segment between the two points extending inward of the arc passes through a position farther from the arc than the center point of the arc.

7. A highly shape-stable retractor according to any one of claims 1 to 3, characterized in that the thickness of the plate in the thickness direction is 0.1 mm or more and less than 0.5 mm.

8. A highly dimensionally stable retractor as claimed in any one of claims 1 to 3, characterized in that the central portion, which is the portion sandwiched between the portion near the first end and the portion near the second end, has a wavy portion on at least one edge in the width direction that undulates in the width direction.

9. A highly dimensionally stable retractor as claimed in any one of claims 1 to 3, characterized in that the central portion, which is the portion sandwiched between the portion near the first end and the portion near the second end, has an uneven portion on at least one edge in the width direction that is uneven in the width direction.

10. A highly shaped retractor as claimed in any one of claims 1 to 3, characterized in that a central portion sandwiched between the portion near the first end and the portion near the second end is provided with a plurality of quadrilateral portions of approximately quadrilateral shape having long sides in the width direction and recessed or protruding in the thickness direction, and in a state in which the ring is formed, each of the quadrilateral portions is recessed radially inward of the curve or protruding radially outward on the outer surface of the curve.

11. A highly dimensionally stable retractor according to claim 1, characterized in that the resin component contains polyether ether ketone resin.

Images