Retractor

Abstract

To provide a retractor for holding an operation field in an easy-to-see state from the incision part of a human body to be incised and securing a wider operation area for an operation.SOLUTION: A retractor (31) partially or entirely inserted into a body cavity of a patient, the retractor (31) containing a synthetic resin as a main resin component, the synthetic resin having chemical resistance and being an elastic material, the retractor (31) having a first end (38) and a second end (39) separated from the first end in a state of being developed in a plate shape, the retractor (31) having a width direction, the retractor (31) being configured to be elastically curved from a plate state so that the first end and the second end overlap each other in a thickness direction of the plate state to form a ring, in a first end vicinity part 35 near the first end, a through-hole 32 through which the second end can be passed is opened, and the diameter of the ring can be changed by changing the length of the distance for passing the second end through the through-hole, and the formed ring has its outward surface constituting the side surface of an approximately truncated cone, and is inserted into the body sequentially from the side having the larger diameter.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to a retractor used during surgery, and more particularly to a retractor that maintains a state in which the surgical field can be more easily seen from the wound opening in the human body to be incised, and that ensures a larger surgical area for surgery. [Background technology]

[0002] Conventionally, there is a retractor having multiple wires arranged at intervals to form a truncated cone shape whose diameter increases toward the bottom (Patent Document 1). For example, a retractor (10) as shown in FIG. 32 has multiple wires (14) fixed to a base (12) that are inclined as shown in the figure, and these wires have elasticity. Therefore, by applying force, each wire can be bent toward the center line of the truncated cone, making the maximum diameter of the entire retractor smaller than the diameter of the wound area. Then, after passing the wound area from its bottom side, this conventional retractor can return each wire to its original straight shape, allowing treatment to be performed while the bottom side remains inside the body cavity.

[0003] Because each wire returns to its straight shape, even a relatively small incision can secure the surgical area within the body cavity by passing through it. Furthermore, each wire reduces the intrusion of surgical obstructions, such as internal organs, into the surgical area, maintaining a clear view of the surgical field from the incision. Furthermore, when the procedure is complete, each wire can be bent again, allowing the retractor to be passed through the incision and withdrawn. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-61133 Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional retractors described above use multiple wires to prevent surgical obstructions from entering the surgical area, but relatively small surgical obstructions can enter the gaps between the wires, blocking the surgical field and narrowing the surgical area. Even if they do not enter, if a surgical obstruction gets caught in the gaps between the wires, it may be impossible to bend the wires again after the surgery is completed, making it difficult to pull the retractor out of the wound.

[0006] Furthermore, some surgical obstructions contain a lot of fat, and if the fat accumulates in the gaps between the wires, it takes a lot of effort to clean them.

[0007] In view of the above problems, the present invention has an object to provide a retractor that securely holds the surgical field and surgical area and is easy to handle. [Means for solving the problem]

[0008] (1) The present invention provides a retractor that can be inserted partially or entirely into a patient's body cavity to secure a surgical field and surgical area, the retractor containing a synthetic resin that is chemically resistant and elastic as its main resin component, that has a first end and a second end spaced apart from the first end when unfolded into a plate, and that has a width direction, 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 distance the second end is passed through the through-hole, and that the outward surface of the formed ring forms the side of an approximately truncated cone, and that is inserted into the body cavity in order from the side with the larger diameter.

[0009] That is, the retractor of the present invention is formed in a generally truncated cone shape configured to be inserted into a body cavity from the larger diameter side, allowing the surgeon to perform surgery by looking into the body cavity from one of the smaller diameter sides. Therefore, a relatively wide surgical field corresponding to the base of the generally truncated cone can be obtained, while the wound opening can be kept smaller in area than the base. Furthermore, the diameter of the ring can be changed by varying the length of the second end through the through-hole. After the portion corresponding to the base of the generally truncated cone is passed through the wound opening with the ring diameter kept as small as possible, surgery can be performed with the ring diameter expanded. In this way, the wound opening can be kept smaller in area than the base. Therefore, the retractor of the present invention can maintain a wider surgical field and a larger surgical area within the body cavity while keeping the area of ​​the wound opening small.

[0010] Furthermore, in the retractor of the present invention, the outward surface of the formed ring constitutes the side surface of a substantially truncated cone, so that surgical obstructions are less likely to enter or become pinched as in conventional retractors.

[0011] Furthermore, since the 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 wound retractor of the present invention has a through-hole near the first end, there is little risk that the first end and the second end will separate when the second end is passed 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 wound retractor of the present invention suddenly expanding or contracting, thereby stabilizing the shape during use.

[0013] (2) In addition, in the central portion sandwiched between the first end vicinity portion and the second end vicinity portion, the center line in the width direction may form an arc in the unfolded state.

[0014] That is, because the center line of the central portion describes an arc, the 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 a roughly 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 slopes to form the side surface of the narrowing half of the roughly truncated cone. Similarly, the outer half of the center line forms a curved surface that slopes to form the side surface of the widening half of the roughly truncated cone.

[0015] As a result, the retractor of the present invention, when curved to form a loop, can be easily formed into a roughly truncated cone shape, and can reliably maintain a wide surgical field and a large surgical area within the body cavity.

[0016] (3) 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.

[0017] The inventors discovered that when the center line of a retractor forms an arc, 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 take on a spiral 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 deviate toward the axial center of the truncated cone, resulting in a spiral shape. Furthermore, the inventors discovered that when the second end of such a 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, a force is applied to the retractor that biases the second end toward the expanded diameter side of the truncated cone. Under this condition, the outward and inward surfaces of the retractor may form distorted front and back surfaces of the truncated cone, respectively.

[0018] In contrast, we found that when the line segment of the through hole in a retractor whose center line describes an arc is inclined so that an extension line extending inward of the arc passes through a position farther from the arc than the center point of the arc, 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, we found that the second end easily passes through the through hole in a direction perpendicular to the inclination direction, but 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 retractor that tends to bias the second end toward the narrowing side of the truncated cone, which is the easier side to pass through.

[0019] As described above, in the retractor of the present invention, because the center line describes 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 retractor can form the front and back surfaces of the truncated cone, respectively, with relatively little distortion. A retractor formed in this manner with a stable, approximately truncated cone shape can reliably maintain a wide surgical field and a large surgical area within a body cavity.

[0020] (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.

[0021] Even if the center line of the retractor does not form an arc, the inclined line segment of the through hole allows the extensions of the generatrix lines at different positions from the first end to the second end to intersect or approach each other when the second end passes through the through hole in a direction perpendicular to the inclined line segment, so that the outward surface forms part of the side of a generally 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 retractor, the second end easily passes through the through hole in a direction perpendicular to the inclination direction, but it is likely to get 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 such a retractor, the inclined line segment of the through hole allows the outward surface to form part of the side of a generally truncated cone, and the diameter can be appropriately changed to stabilize the generally truncated cone shape. As a result, a retractor formed in this generally truncated cone shape can reliably maintain a wide surgical field and a large surgical area within a body cavity.

[0022] (5) 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.

[0023] In other words, even when the retractor forming the loop tries to expand, the locked portion catches around the through-hole, and the portion near the second end is locked by the portion near the first end in a direction that tends to shrink the loop, preventing further expansion. This allows the retractor of the present invention to maintain a stable shape during use and is easy to handle.

[0024] (6) The present invention may also have 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 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.

[0025] 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.

[0026] 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 the constricted portion narrows the engaging 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.

[0027] (7) In addition, when the ring is formed, the side surface may be configured to have a protruding portion that protrudes radially outward from the edge on the smaller diameter side of both end edges of the side surface.

[0028] That is, when the edge of the smaller diameter side of the retractor is slightly outside the patient's body cavity, the underside of the overhanging portion can abut against the body surface so as to spread from the inner edge of the wound opening. In this state, even if the retractor is about to sink deep into the body cavity, the patient's body surface can stop the overhanging portion from moving outward. In this way, the retractor of the present invention can be used in an appropriate position. [Effects of the Invention]

[0029] As described above, the present invention provides a wound retractor that can maintain a wide surgical field and a large surgical area within the body cavity while reducing the area of ​​the wound opening, can stabilize its shape during use, and is easy to handle. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a view showing a retractor according to a first embodiment of the present invention in an unfolded state. [Figure 2](a) shows a traced image of the retractor in Fig. 1 in the assembled state when viewed from diagonally above the vicinity of the through-hole. (b) shows a traced image of the retractor in (a) when viewed from the front, with the vicinity of the through-hole as the front. [Figure 3] (a) A traced image of the vicinity of the through-hole as viewed from diagonally above with the insertion end of the retractor in Figure 2 deeply inserted. (b) A traced image of the retractor in (a) as viewed from the front. [Figure 4] 3 shows a front view of the retractor of FIG. 2 in a state where a portion near the through-hole and a portion near the locked portion overlap each other in the front-rear direction. [Figure 5] 5 shows a front view of the retractor of FIG. 4 with the insertion end advanced to the left. [Figure 6] 3(a) is a schematic diagram showing a state in which a part of the retractor of FIG. 2 is inserted into a body cavity, and FIG. 3(b) is a schematic diagram showing a state in which a part of the retractor of FIG. 3 is inserted into a body cavity. [Figure 7] 1A is a diagram showing a modified example of the first embodiment of the present invention in an unfolded state of the retractor, and FIG. 1B is a diagram showing a trace of an image of the retractor in an assembled state as viewed from the front of the retractor in FIG. [Figure 8] 10 is a view showing a retractor according to a second embodiment of the present invention in an unfolded state. [Figure 9] 9 is a partially enlarged view showing the vicinity of the through-hole of the retractor of FIG. 8. [Figure 10] (a) shows a traced image of the retractor in Fig. 8 in the assembled state when viewed obliquely from above near the through-hole. (b) shows a traced image of the retractor in (a) when viewed from the front, with the area near the through-hole facing forward. [Figure 11] (a) A traced image of the vicinity of the through-hole as viewed from diagonally above with the insertion end of the retractor in Fig. 10 inserted deeply. (b) A traced image of the retractor in (a) as viewed from the front. [Figure 12] 10 is a view showing a retractor according to a third embodiment of the present invention in an unfolded state. [Figure 13]12 in an assembled state, viewed from diagonally above the vicinity of the through-hole. (a) A traced image of the retractor in (a) in an assembled state, viewed from diagonally above the vicinity of the through-hole with the insertion end of the retractor deeply inserted. [Figure 14] 13(a) and 13(b) are schematic diagrams showing a state in which the retractor of FIG. 13(a) is partially inserted into a body cavity, respectively. [Figure 15] 10 is a view showing a modified example of the retractor according to the third embodiment of the present invention in an unfolded state. [Figure 16] 10(a) shows a view of the retractor according to the fourth embodiment of the present invention in an unfolded state, and FIG. 10(b) shows a partially enlarged view of the through-hole of the retractor in FIG. [Figure 17] 17 shows a traced image of the wound retractor of FIG. 16 in an assembled state, viewed obliquely from above in the vicinity of the through-hole. [Figure 18] 17 shows a front view of the wound retractor in the assembled state in which the central portion of the portion near the locked portion and the portion adjacent thereto are passed through the through-hole and overlapped at the rear. FIG. [Figure 19] 19 is a front view showing 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. FIG. [Figure 20] FIG. 10 is a view showing a first modified example of the retractor according to the fourth embodiment of the present invention in an unfolded state. [Figure 21] 10(a) and 10(b) are views showing a second modified example and a third modified example of the fourth embodiment of the present invention, respectively, in an unfolded state of the retractor. [Figure 22] 10(a) and 10(b) are views showing a fourth modified example and a fifth modified example of the fourth embodiment of the present invention, respectively, in an unfolded state of the retractor. [Figure 23] 10A is a view showing a state in which a retractor showing a sixth modified example related to the fourth embodiment of the present invention is unfolded; FIG. 10B is a view showing the retractor of FIG. 10A as viewed from above; FIG. 10C is a partially enlarged view of FIG. 10B. [Figure 24] 10 shows a view of a wound retractor according to a fifth embodiment of the present invention in an unfolded state. [Figure 25] 25 shows an enlarged partial view of the retractor through-hole of FIG. 24. [Figure 26] 25 shows a traced image of the wound retractor of FIG. 24 in an assembled state, viewed obliquely from above in the vicinity of the through-hole. [Figure 27] 27 shows a front view of the state in which the portion near the locked portion is pulled in the opposite direction to the insertion direction from the state of FIG. 26. FIG. [Figure 28] 13 shows a view of a retractor in an unfolded state according to a sixth embodiment of the present invention. [Figure 29] 29 shows an enlarged partial view of the retractor through-hole of FIG. 28. [Figure 30] 29 shows a traced image of the wound retractor of FIG. 28 in an assembled state, viewed obliquely from above in the vicinity of the through-hole. [Figure 31] 31 shows a front view of the state in which the portion near the locked portion is pulled all the way to the right from the state in FIG. 30. FIG. [Figure 32] 1 shows a perspective view of a conventional retractor. DETAILED DESCRIPTION OF THE INVENTION

[0031] [First embodiment] A first embodiment of the present invention will be illustrated using Figs. 1 to 7. In Fig. 1, 11 is a retractor. This retractor is an instrument that is inserted partially or entirely into a patient's body cavity during surgery to secure a surgical area. The retractor 11 of the present invention is an arc-shaped thin plate when unfolded into a plate shape as shown in Fig. 1. Arrow CI shown in Fig. 1 points in the circumferential direction of the retractor 11, and arrow W also points in the width direction. Although not shown in Fig. 1, the retractor 11 has a thickness that is in the depth direction of the figure.

[0032] In its deployed state, the retractor 11 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 right side of the figure, and the second end is located on the left 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 retractor 11. Of the pair of locking portions 13, 14, the first locking portion 13 is provided facing downward and left in Figure 1, which is away from the center line CL of the retractor 11 with respect to the center point C of the arc shape, and the second locking portion 14 is provided facing upward and right in Figure 1, which is closer to the center line CL. The portion near the first end is also simply referred to as the portion near the first end or the through-hole portion 15, and the portion near the second end is also simply referred to as the portion near the second end or the locked portion portion 16.

[0033] The central portion that is sandwiched between the through-hole vicinity portion 15 and the locked portion vicinity portion 16 in the circumferential direction is called the central portion 17. When the retractor 11 is unfolded, the central portion 17 has a width and extends in an arc shape centered on a center point C. The retractor 11 has a center line CL located in the center in the width direction, and the center line CL forms an arc centered on the center point C. In addition, both ends 17a, 17b of the central portion 17 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 17a, which is the outer end in the width direction of the central portion 17, and the inner end 17b, which is the inner end in the same direction, is slightly shorter than the through width W1, which is the width of the through hole 12 in the width direction.

[0034] The locked portion neighboring portion 16 has a narrowed portion 20 recessed inward in the width direction. The narrowed portion 20 is located adjacent to the first locked portion 13, closer to the central portion 17.

[0035] The first end is also referred to as an inserted end 18, and the second end is also referred to as an inserting end 19.

[0036] The retractor 11 can be elastically bent from a plate state, with the insertion end 18 side and the insertion end 19 side overlapping in the thickness direction of the plate state and curling into a ring. The inventors produced a prototype retractor 11 by cutting a 0.4 mm thick polyether ether ketone resin (PEEK) plate material, described below, as shown in the developed view of FIG. 1. FIG. 2(a) is a traced image of the prototype, viewed obliquely from above the through-hole vicinity 15, after the insertion end 19 has been bent from the arc-shaped state shown in FIG. 1 so that it faces backward and is then inserted into the through-hole 12 from the front. As shown in this figure, the insertion end 19 is inserted through the through-hole 12 from the outside of the ring toward the inside. FIG. 2(b) is a traced image of the prototype viewed from the front, with the through-hole vicinity 15 facing forward. The state shown in these figures is referred to as the assembled state. The direction of arrow U indicates the upward direction of the retractor 11 in the assembled state in each figure, and the direction of arrow D indicates the downward direction in each figure. The direction of arrow L indicates the leftward direction in each figure, and the direction of arrow R indicates the rightward direction in each figure. The direction of arrow F indicates the forward direction in each figure, and the direction of arrow B indicates the backward direction in each figure.

[0037] The outward surface of the retractor 11 in the assembled state forms the side of a substantially truncated cone whose diameter increases toward the bottom. However, the arrows U, D, L, R, F, and B do not necessarily indicate the upward, downward, left, right, front, and rear directions, respectively, when the retractor 11 is in use. Furthermore, the retractor 11 can be assembled not only by bending the insertion end 19 so that it faces backward as shown in Figures 2(a) and 2(b), but also by bending the insertion end 19 so that it faces forward, in which case the assembled state is shown reversed left and right. In this way, the retractor 11 can be used in the upward, downward, 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.

[0038] The retractor 11 can be inserted deeper by sliding the insertion end 19 leftward relative to the through-hole 12. FIG. 3(a) shows a traced image of a prototype of the retractor 11 viewed from diagonally above the front in a state in which the insertion end 19 has been inserted deeply from the state shown in FIGS. 2(a) and 2(b), and FIG. 3(b) shows a traced image of the prototype as viewed from the front. The insertion end 19 can then be slid back to its original position in the opposite direction. The retractor 11 can freely change the diameter of the ring by changing the position of the insertion end 19 relative to the through-hole 12. Furthermore, even if some force is applied from the outside or inside of the retractor 11 while it is being worn, this force can be absorbed by changing the diameter.

[0039] 3(b), a portion of the through-hole vicinity center line CL15, which is the center line CL in the through-hole vicinity portion 15, is indicated by a dashed line, and a portion of the locked-portion vicinity center line CL16, which is the center line CL in the locked-portion vicinity portion 16, is indicated by a broken line. A portion of the locked-portion vicinity center line CL16 is located below a portion of the through-hole vicinity center line CL15, and these center lines CL15, CL16 are at least partially offset from each other vertically.

[0040] The state in which the insertion end 19 is passed through the through-hole 12 will be described in detail with reference to Figures 4 and 5. Similar to Figures 2 and 3, Figures 4 and 5 show a front view of the state in which the through-hole vicinity 15 located on the left side and the locked portion vicinity 16 located on the right side overlap in the front-to-back direction. In the front view, the insertion end 19 is hidden behind the through-hole vicinity 15. However, for ease of understanding, all of the overlapping portions that should be shown with hidden lines are shown with solid lines. Figure 4 shows the state in which the first locked portion right end 13a, which is the right end of the first locked portion 13, and the second locked portion right end 14a, which is the right end of the second locked portion 14, are close to the through-hole right edge 12a, which is the right edge of the through-hole 12, in the left-right direction.

[0041] As shown in Figure 4, the locked portion vicinity portion 16 has a constricted portion 20 that is recessed upward and inward in the width direction. The constricted portion 20 is located immediately to the right 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 right end 13a of the first locked portion are continuous in the up-down direction. The upper half of the constricted portion 20 is formed in a roughly semicircular shape with an arc on the upper side.

[0042] 4, in the width direction, through-hole width W1, which is the width of through-hole 12, is shorter than maximum width W2, which is the distance between the lower end of first locked portion 13 and the upper end of second locked portion 14. Therefore, in order to pass insertion end 19 through through-hole 12, locked portion neighboring portion 16 is tilted clockwise CL with respect to through-hole neighboring portion 15, and first locked portion 13 is passed through through-hole 12, and then second locked portion 14 is passed through through-hole 12. At this time, because locked portion neighboring portion 16 has constricted portion 20, first first locked portion 13 is passed through through-hole 12, and then locked portion neighboring portion 16 is moved downward so that the lower edge of through-hole 12 and the deepest portion of 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 upper edge of the portion 16 adjacent to the engaged portion, is shorter than the through-hole width W1, the second engaged portion 14 can easily pass through the through-hole 12.

[0043] Moreover, because the through-hole width W1 is shorter than the maximum width W2, even when the locked portion neighboring portion 16 is pulled rightward relative to the through-hole neighboring portion 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 leftward. In this way, the locked portion neighboring portion 16 is locked leftward by the through-hole neighboring portion 15.

[0044] 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 rightward 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 to the right 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 5 shows an example of a state in which the insertion end 19 moves leftward 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 order, smallest to largest: minimum width W3, normal width W4, through-hole width W1, and maximum width W2.

[0045] The retractor 11 is formed, for example, from a synthetic resin. Among synthetic resins, it is preferable to use a resin containing polyether ether ketone resin as the main resin component. Polyether ether ketone resin is a material that is chemically resistant and elastic. Since the manufacturer ships the polyether ether ketone resin in the form of a thin plate, the manufacturer of the retractor 11 shapes it into a predetermined shape by machining it, such as cutting or drilling, as necessary. In addition to polyether ether ketone resin, a chemically resistant engineering plastic such as polyphenylene sulfide resin (PPS) may also be used.

[0046] Furthermore, the thickness of 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 thickness of the retractor of the present invention is 0.1 mm or more and less than 0.5 mm, the retractor is less likely to injure the affected area and the shape of the ring is more stable. If retractor 11 is too thin, there is a high risk of injuring the skin, the inside of the body cavity, the affected area, or the area around the affected area. If retractor 11 is too thick, the repulsive force is too strong and the adjacent portions 15, 16 do not overlap in the specified positions.

[0047] As shown in the schematic diagram of FIG. 6( a), the retractor 11 is inserted into the body cavity starting from the larger diameter side. Because it is formed in a generally truncated cone shape, the surgeon can perform surgery by looking into the body cavity from the smaller diameter side. Because the generally truncated cone widens toward the bottom, a wider surgical field can be obtained. In FIGS. 6( a) and 6(b), the symbol Sk represents the patient's skin, and the area below the skin Sk represents the body cavity. These figures also show a schematic representation of a state in which a portion of the retractor 11 is inserted into the body cavity. The symbol Ks represents the wound portion made in the skin Sk. The wound portion Ks is formed, for example, in a generally elliptical, circular, or rectangular shape in a plan view. With this vertical relationship, the retractor 11 is inserted in a direction that widens its diameter toward the bottom of FIG. 6( a). By inserting the retractor 11, a surgical area is secured within the retractor 11. Although FIG. 6(a) shows a state in which only a part of the retractor 11 is inserted into the body cavity, the entire retractor 11 may be inserted into the body cavity.

[0048] With the above configuration, the retractor 11 can obtain a relatively wide surgical field corresponding to the base of a truncated cone, while keeping the wound opening Ks smaller in area than the base. Furthermore, the diameter of the ring can be changed by varying the length of the insertion end 19 through the through-hole 12. Therefore, the portion corresponding to the base of the truncated cone can be passed through the inside of the wound opening Ks with the ring diameter kept as small as possible, as shown in FIG. 6(b). Surgery can then be performed with the ring diameter expanded, as shown in FIG. 6(a). Thus, the retractor 11 can maintain a wide surgical field and a large surgical area within the body cavity while keeping the area of ​​the wound opening Ks small.

[0049] Furthermore, since the retractor 11 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 synthetic resin makes it easy to mold into a thin plate shape.

[0050] Furthermore, because the retractor 11 has the through hole 12 formed in the through hole vicinity 15, there is little risk that the insertion end 18 side and the insertion end 19 side will separate when the insertion end 19 is inserted through the through hole 12. This stabilizes the shape during use. Furthermore, the insertion end 18 side and the insertion end 19 side are securely in contact with each other, generating friction between them. This reduces the possibility that the ring of the retractor 11 will suddenly expand or contract, thereby stabilizing the shape during use.

[0051] Furthermore, because the center line CL of the central portion 17 describes a circular arc, the retractor 11 forms a curved shape by curving from a plate state to form a loop, and the outward surface thereof forms the side surface of a roughly 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 CL forms a curved surface that slopes to form the half side surface 11s of the narrowing diameter side of the roughly truncated cone, as shown in FIG. 2(b). Similarly, the outer half of the center line CL forms a curved surface that slopes to form the half side surface 11e of the widening diameter side of the roughly truncated cone. As a result, the retractor 11 in the curved loop state can be easily formed into a roughly truncated cone shape, and a wide surgical field and a large surgical area within the body cavity can be reliably maintained.

[0052] Furthermore, even when the retractor 11 forming the loop tries to expand, the locked portions 13 and 14 are caught around the through-hole 12, and the portion 16 in the vicinity of the locked portion is locked by the portion 15 in the vicinity of the through-hole in the direction that tends to shrink the loop, thereby preventing further expansion. This allows the retractor 11 to maintain a stable shape during use and makes it easy to handle.

[0053] In addition, since it has a pair of engaging portions 13, 14 that protrude in both width directions, each engaging portion 13, 14 catches around the through hole 12, and the engaging portion vicinity 16 is efficiently engaged by the through hole vicinity 15.

[0054] Furthermore, since the first locked portion 13 has a constricted portion 20 and protrudes from this constricted portion 20, the second locked portion 14 can pass through the through hole 12 even if the width of the through hole 12 is small because it is narrowed by the constricted portion 20. By reducing the width of the through hole 12 in this way, the locked portions 13, 14 can be easily caught around the periphery of the through hole 12, and the locked portion vicinity portion 16 is more efficiently locked by the through hole vicinity portion 15.

[0055] [Variations] 7(a) and (b) show a modified example of the first embodiment of the retractor according to the present invention. In the figures, reference numeral 111 denotes the retractor. Unless otherwise specified, the configuration of the retractor 111 in this modified example is the same as the configuration of the retractor 11 in the above-described embodiment.

[0056] As shown in the development view of Fig. 7(a), the constricted portion 201 is recessed not adjacent to the central portion 171 of the first locked portion 131 but adjacent to the central portion 171 of the second locked portion 141. Fig. 7(b) shows a front view of the retractor 111 in an assembled state.

[0057] As in the above-described embodiment and its modified example, the constricted portion may be recessed either on the outside or inside of the arc when the retractor is in a plate state, i.e., the constricted portion may be recessed either on the top or bottom side of each drawing when the retractor is in an assembled state.

[0058] 7(b), a portion of the through-hole vicinity center line CL151, which is the center line CL in the through-hole vicinity portion 151, is indicated by a dashed line, and a portion of the locked portion vicinity center line CL161, which is the center line CL in the locked portion vicinity portion 161, is indicated by a broken line. A portion of the locked portion vicinity center line CL161 is located below a portion of the through-hole vicinity center line CL151, and these center lines CL151, CL161 are at least partially offset from each other in the vertical direction.

[0059] [Second embodiment] A second embodiment of the present invention will be illustrated using Figures 8 to 11. In Figure 8, 21 is a retractor. In the unfolded state as shown in Figure 8, retractor 21 has an insertion end 28 and an insertion end 29. A through hole 22 is formed in a through hole vicinity 25, which is a portion near insertion end 28. A pair of locked portions 23, 24 is provided in an locked portion vicinity 26, which is a portion near insertion end 29. Each of locked portions 23, 24 is provided so as to protrude outward in both directions in the width direction of retractor 21.

[0060] A normal width W4, which is the distance between the outer end 27a and the inner end 27b of the central portion 27, is slightly shorter than a right-angled triangle height W5, which is the length of the through-hole 22 in the width direction.

[0061] The locked portion neighboring portion 26 has a narrowed portion 30 recessed inward in the width direction. The narrowed portion 30 is located adjacent to, and closer to, the central portion 27 of the first locked portion 23, which protrudes away from the center line CL relative to the center point C.

[0062] FIG. 9 is a partially enlarged view of the vicinity of the through-hole vicinity 25 of the retractor 21. The through-hole 22 has a first point 22a, which is a point at the lower right of FIG. 9, and a second point 22b, which is a point at the upper left, on the edge of its inner periphery on the side of the insertion end 28. The first point 22a is located toward the outside of the center line CL of the retractor 21, and the second point 22b is located toward the inside. A linear insertion-end-side edge 22ab of the through-hole 22 extends between the first point 22a and the second point 22b. That is, a straight line segment connecting the first point 22a and the second point 22b follows the insertion-end-side edge 22ab. As shown in FIG. 9, an inward extension line 22ab' extends from the line segment connecting the first point 22a and the second point 22b, and is an extension of this line segment that extends inward of the arc.

[0063] The inward extension line 22ab' passes through an intersection point CRab, which is farther from the center point C with respect to the arc of the center line CL.

[0064] The through hole 22 has a third point 22c, which is a point at the lower right in FIG. 9, and a fourth point 22d, which is a point at the upper left, on the inner periphery of the insertion end 29 side. The third point 22c is located outward from the center line CL of the retractor 21, and the fourth point 22d is located inward. 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 line segment connecting the third point 22c and the fourth point 22d runs along the insertion end side edge 22cd. As shown in FIG. 9, an inward extension line 22cd' extends from the line segment connecting the third point 22c and the fourth point 22d, which is an extension of this line segment and is an inward extension of a circular arc. This inward extension line 22cd' also passes through the intersection point CRcd, which is farther from the center point C with respect to the arc of the center line CL.

[0065] As described above, in the through-hole 22, both the line segment along the insertion end side edge 22ab and the line segment along the insertion end side edge 22cd are inclined with respect to the width direction of the retractor 21.

[0066] The retractor 21 can bend elastically from a plate state, with the insertion end 28 side and the insertion end 29 side overlapping in the thickness direction of the plate state and curling up to form a ring. The inventors produced a prototype retractor 21 by cutting a 0.4 mm thick polyether ether ketone resin plate material as shown in the developed view of FIG. 8. FIG. 10(a) is a traced image of the prototype, viewed obliquely from above the through-hole vicinity 25, after the insertion end 29 has been curved from the arc-shaped state shown in FIGS. 8 and 9 so that it faces backward and has been passed through the through-hole 22 from the front. FIG. 10(b) is a traced image of the prototype viewed from the front, with the through-hole vicinity 25 facing forward.

[0067] The retractor 21 can be inserted deeper by sliding the insertion end 29 leftward relative to the through-hole 22. FIG. 11(a) shows a traced image of a prototype of the retractor 21 viewed from diagonally above the front in a state where the insertion end 29 has been inserted deeply from the state shown in FIGS. 10(a) and 10(b), and FIG. 11(b) shows a traced image of the prototype as viewed from the front. The insertion end 29 can then be slid back to its original position in the opposite direction. The retractor 21 allows the position of the insertion end 29 relative to the through-hole 22 to be changed in this way, so that the diameter of the loop can be freely changed. Furthermore, even if some force is applied from the outside or inside of the retractor 21 while it is being worn, this force can be absorbed by changing the diameter.

[0068] 11(b), a portion of the through-hole vicinity center line CL25, which is the center line CL in the through-hole vicinity portion 25, is indicated by a dashed line, and a portion of the locked-portion vicinity center line CL26, which is the center line CL in the locked-portion vicinity portion 26, is indicated by a broken line. A portion of the locked-portion vicinity center line CL26 is located below a portion of the through-hole vicinity center line CL25, and these center lines CL25, CL26 are at least partially offset from each other in the vertical direction.

[0069] The other configurations are the same as those in the first embodiment.

[0070] Regarding these configurations, the inventors discovered that when the center line of the retractor describes an arc, the elastic force generated when the retractor curves from a plate shape to form a loop tends to cause the wound three-dimensional shape to form a spiral. In other words, if the insertion end is not passed through the through hole, the wound retractor tends to form a spiral shape because the portions near the insertion end and the insertion end are misaligned toward the axial center of the truncated cone. Furthermore, the inventors discovered that when the insertion end of such a retractor is passed through the through hole, the portion near the insertion end tends to protrude toward the expanded side of the truncated cone, resulting in a lack of overlap with the portion near the insertion end from the previous turn. For example, in the state shown in Figures 3(a) and (b) of the retractor 11 according to the first embodiment, the center line CL16 near the locked portion is located below the center line CL15 near the through hole, and as can be seen from the fact that these center lines CL15, CL16 are offset up and down, it can be seen that the portion close to the insertion end 19 is located lower than the portion close to the inserted end 18. Also, in the state shown in Figures 2(a) and (b), although this is not noticeable, the portion close to the insertion end 19 is also located slightly lower than the portion close to the inserted end 18. Thus, a force is applied to the retractor that tends to bias the insertion end toward the expanded diameter side of the truncated cone, and in this state, the outward and inward surfaces of the retractor may form the front and back surfaces of a distorted truncated cone, respectively.

[0071] In contrast, it was found that when line segments along the edges 22ab, 22cd of the through hole 22 in a retractor whose center line CL describes an arc, such as the retractor 21 according to the second embodiment, are inclined so that extension lines 22ab', 22cd' extending inward from the arc pass at a position farther from the arc than the center point C of the arc, the insertion end 29 that has made a full circle and passed through the through hole 22 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 the examples of Figures 10 and 11, the insertion end 29 tends to move toward the upper side, which is the narrowing side. That is, it was found that the insertion end 29 easily passes through the through hole 22 in a direction perpendicular to the inclination direction, but that it is easily caught around the through hole 22 in a direction not perpendicular to the inclination direction, making it difficult to pass through the through hole 22. Therefore, a force is applied to the retractor 21 such that the insertion end 29 tends to be biased toward the upper side where it is easier to pass through.

[0072] As described above, in the retractor 21, the center line CL forms an arc and the through hole 22 is inclined in a predetermined direction, making it possible to balance as much as possible the force biasing the insertion end 29 toward the enlarged-diameter side of the truncated cone with the force biasing the insertion end 29 toward the reduced-diameter side. As a result, compared to the first embodiment, the insertion end 29 is less likely to deviate significantly toward either the enlarged-diameter side or the reduced-diameter side, and the outward and inward surfaces of the retractor 21 can form the front and back surfaces of the truncated cone with relatively little distortion. While the center line CL26 near the locking portion shown in FIG. 11(b) is located below the through hole center line CL25, this is less than the degree to which the center line CL16 near the locking portion shown in FIG. 3(b) is located below the through hole center line CL15 in the first embodiment. The retractor 21 thus formed into a stable, approximately truncated cone shape can reliably maintain a wide surgical field and a large surgical area within a body cavity.

[0073] [Third embodiment] A third embodiment of the present invention will be illustrated using Figures 12 to 15. In Figure 12, 31 is a retractor. In the unfolded state as shown in Figure 12, the retractor 31 has an insertion end 38 and an insertion end 39. A through hole 32 is formed in a through hole vicinity 35, which is the portion near the insertion end 38. A pair of locked portions 33, 34 is provided in an locked portion vicinity 36, which is the portion near the insertion end 39. Each of the locked portions 33, 34 is provided so as to protrude outward on both sides in the width direction of the retractor 31. Of the pair of locked portions 33, 34, the first locked portion 33 is provided facing downward and left in Figure 12, which is an orientation away from the center line CL of the retractor 31 with respect to the center point C of the arc shape, and the second locked portion 34 is provided facing upward and right in Figure 12, which is an orientation toward the center line CL.

[0074] The central portion 37 is a portion sandwiched between the through-hole vicinity portion 35 and the locked portion vicinity portion 36 in the circumferential direction. When the wound retractor 31 is unfolded, the central portion 37 has a width and extends in an arc shape centered on a center point C. The central portion 37 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. An outer end 37a, which is the outer end of the central portion 37 in the width direction, and an inner end 37b, which is the inner end, also form arcs centered on the center point C. The locked portion vicinity portion 36 has a constricted portion 40 recessed inward in the width direction. The constricted portion 40 is located adjacent to the first locked portion 33, closer to the central portion 37.

[0075] In the example of FIG. 12 , protruding portions 37c and 37d are provided on the inner end 37b of the central portion 37, protruding toward the center line C. The protruding portions 37c and 37d are each formed, for example, in a substantially rectangular shape. The first protruding portion 37c is provided near the through-hole vicinity 35, and the second protruding portion 37d is provided near the locked portion vicinity 36 closer than the first protruding portion 37c. While the example of FIG. 12 shows two first and second protruding portions 37c and 37d, they may be provided in one location, or three or more locations as long as they do not interfere with each other in the assembled state. In the example of FIG. 12 , both protruding portions 37c and 37d are provided on the central portion 37, but they may be provided in the through-hole vicinity 35 or the locked portion vicinity 36 as long as they do not interfere with assembly.

[0076] Fig. 13(a) is a perspective view of the retractor 31 in an assembled state obtained by rolling the retractor 31 in the unfolded state shown in Fig. 12 to form a loop. When the loop of the retractor 31 is formed, each of the protruding portions 37c, 37d protrudes radially outward from the inner end 37b. In this example, the inner end 37b corresponds to the edge with a smaller diameter of both end edges in the width direction of the side surface of the retractor 31, which forms a substantially truncated cone shape. Fig. 13(b) is a perspective view of the retractor 31 in a state in which the insertion end 39 is inserted more deeply.

[0077] 14(a) and 14(b), like FIGS. 6(a) and 6(b), are schematic diagrams showing the relationship between the retractor 31 and the patient's skin portion Sk, the wound opening Ks, and the inside of the body cavity. As shown in FIG. 14(a), a portion of the lower surface of the first overhanging portion 37c abuts on the upper surface of the skin portion Sk adjacent to the wound opening Ks. The wound opening Ks is formed, for example, in a substantially circular or substantially rectangular shape in plan view. Although not shown in the figure, a portion of the lower surface of the second overhanging portion 37d abuts on the upper surface of another skin portion Sk adjacent to the wound opening Ks. Furthermore, as shown in FIG. 14(b), when the diameter of the ring is made as small as possible, the retractor 31 can be passed inside the wound opening Ks with these overhanging portions 37c and 37d still overhanging.

[0078] The other configurations are the same as those of the second embodiment.

[0079] With the above configuration, when the edge of the smaller diameter side of the retractor 31 is slightly outside the patient's body cavity, the protruding portions 37c, 37d extend left and right and front and rear from the inner edge of the retractor Ks, and their lower surfaces can abut against the upper surface of the skin portion Sk. In this state, even if the retractor 31 is about to sink deep into the body cavity, the upper surface of the patient's skin portion Sk can prevent the protruding portions 37c, 37d from moving upward. In this way, the retractor 31 can be used in an appropriate position.

[0080] [Variations] 15 shows a modified example of the third embodiment of the retractor according to the present invention. In the figure, reference numeral 311 denotes the retractor. Unless otherwise specified, the configuration of the retractor 311 in this modified example is the same as the configuration of the retractor 31 in the above-described embodiment.

[0081] 15, the through hole 321 of the retractor 311 in this modified example is opened in the width direction of the retractor 311, unlike the through hole 32 of the retractor 31 in the above-described embodiment. Therefore, the configuration of the through hole 321 is common to the through hole 12 according to the first embodiment of the present invention. The configuration of each of the protruding portions 371c, 371d is common to the protruding portions 37c, 37d of the retractor 31 in the above-described embodiment.

[0082] [Fourth embodiment] A fourth embodiment of the present invention will be illustrated using Figures 16 to 23. Figure 16(a) shows a retractor 41 in an unfolded state. The retractor 41 is a thin, rectangular plate when unfolded and flat. The left-right arrow L in the figure indicates the longitudinal direction of the retractor 41, and the up-down arrow W similarly indicates the width direction. Although not shown in the figure, the retractor 41 has a thickness extending in the depth direction of the figure. The retractor 41 has a through-hole 42 in the thickness direction near the insertion end 48, which is the right end in the longitudinal direction. The retractor 41 also has a first locked portion 43 facing downward in Figure 16(a) near the insertion end 49, which is the left end, and a second locked portion 44 facing upward. The portion near the insertion end 48 is also referred to as a through-hole vicinity 45, and the portion near the insertion end 49 is also referred to as a locked portion vicinity 46.

[0083] The central portion that is sandwiched between the through-hole vicinity portion 45 and the locked portion vicinity portion 46 in the longitudinal direction is called the central portion 47. The central portion 47 extends in the longitudinal direction, and both ends in the width direction are parallel to each other. The retractor 11 has a center line CL located in the center in the width direction, and the center line CL forms a straight line in the longitudinal direction. Of both ends in the width direction of the retractor 41, the lower end is called the lower end 47a, and the upper end is called the upper end 47b. The lower end 47a and the upper end 47b of the central portion 47 each form a straight line in the longitudinal direction.

[0084] FIG. 16(b) shows a partially enlarged view of the through hole 42. The through hole 42 has a first point 42a, which is a point at the lower right of FIG. 16(b), and a second point 42b, which is a point at the upper left, on the inner periphery of the through hole 42 on the side of the insertion end 48. The first point 42a is located closer to the lower end 47a, and the second point 42b is located closer to the upper end 47b. A linear insertion end-side edge 42ab of the through hole 42 extends between the first point 42a and the second point 42b. That is, a straight line segment connecting the first point 42a and the second point 42b runs along the insertion end-side edge 42ab. These line segments and the insertion end-side edge 42ab are inclined such that the first point 42a approaches the insertion end 48 and the second point 42b approaches the insertion end 49.

[0085] The through hole 42 also has a third point 42c, which is a point at the lower right, and a fourth point 42d, which is a point at the upper left, on the edge of its inner periphery on the insertion end 49 side. The third point 42c is located closer to the lower end 47a, and the third point 42d is located closer to the upper end 47b. A linear insertion end edge 42cd of the through hole 42 extends between the third point 42c and the fourth point 42d. That is, a line segment connecting the third point 42c and the fourth point 42d runs along the insertion end edge 42cd. These line segments and the insertion end edge 42cd are inclined so that the third point 42c approaches the insertion end 48 and the fourth point 42d approaches the insertion end 49. The insertion end edge 42ab and the insertion end edge 42cd are parallel to each other.

[0086] The retractor 41 can be elastically bent from a plate state, with the insertion end 48 and the insertion end 49 overlapping in the thickness direction of the plate state and forming a roughly circular ring. Figure 17 shows a traced image of the retractor 41, cut out from a 0.4 mm thick polyether ether ketone resin plate according to the development diagram in Figure 16(a), and then curved from a rectangular state so that the insertion end 49 is turned to the back and inserted through the through hole 42 from the front. In other words, the insertion end 49 is inserted through the through hole 42 from the outside to the inside of the ring. The hidden portion of the through hole 42 is indicated by a dashed line. This state is referred to as the assembled state. The arrow U indicates the upward direction of the assembled retractor 41 in each figure, and the arrow D indicates the downward direction in each figure. The arrow L indicates the left in each figure, and the arrow R indicates the right 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 retractor 41 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 retractor 41 is in use. Furthermore, the retractor 41 may be assembled by bending the insertion end 49 backward as shown in FIG. 17 , or by bending the insertion end 49 forward, in which case the assembled state is shown reversed. In this way, the retractor 41 can be used in the upward, downward, 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.

[0087] 17, a portion of the through-hole vicinity center line CL45, which is the center line CL in the through-hole vicinity portion 45, is indicated by a dashed line, and a portion of the locked-portion vicinity center line CL46, which is the center line CL in the locked-portion vicinity portion 46, is indicated by a broken line. A portion of the locked-portion vicinity center line CL46 is located below a portion of the through-hole vicinity center line CL45, and these center lines CL45, CL46 are at least partially offset from each other in the vertical direction.

[0088] FIG. 18 shows an example of a state in which the insertion end 49, inserted into the through-hole 42 from the front side of the figure, advances downward and to the left. That is, after passing through the through-hole 42, the locking portion vicinity 46 overlaps the rear of the through-hole vicinity 45 or the central portion 47 of the adjacent portion. The front side of the figure is the front side of the retractor 41, and the back side is the rear side. Furthermore, for clarity, all overlapping portions that would normally be shown with hidden lines are shown with solid lines. FIG. 18 shows a state in which the direction of the insertion end side edge 42ab coincides with the width direction of the locking portion vicinity 46 and the central portion 47 of the adjacent portion. The insertion direction is approximately perpendicular to the direction of the insertion end side edge 42ab. Furthermore, because the insertion end side edge 42ab is inclined, the width direction of the through-hole vicinity 45 does not coincide with the width direction of the locking portion vicinity 46 and the central portion 47 of the adjacent portion. The same applies to the insertion end side edge 42cd. This state is called the orthogonal insertion state.

[0089] 18, the direction of the insertion-end side edge 42ab coincides with the width direction of the locked-portion neighborhood 46 and the central portion 47 of the portion adjacent thereto, and the through-hole width W1, which is the width of the through-hole 42 in the direction of the insertion-end side edge 42ab, is longer than the normal width W4, which is the distance between the lower end 47a and the upper end 47b of the central portion 47, so the locked-portion neighborhood 46 and the central portion 47 of the portion adjacent thereto can move in the insertion direction through the through-hole 42. However, when the difference between the through-hole width W1 and the normal width W4 is large, the gap is correspondingly large, and the direction of the locked-portion neighborhood 46 and the central portion 47 of the portion adjacent thereto relative to the through-hole 42 in a front view is not determined, which increases the possibility that the direction of the insertion-end side edge 42ab will not coincide with the direction of the locked-portion neighborhood 46 and the central portion 47 of the portion adjacent thereto.

[0090] Furthermore, when the slit width Wa, which is the width of the through hole 42 in the direction perpendicular to the inserted end side edge 42ab, is shorter than a certain width, the locked portion vicinity 46 and the central portion 47 of the adjacent portion are likely to get caught around the through hole 42 and are difficult to pass through. This is because, even though the locked portion vicinity 46 is inserted at a shallow angle relative to the periphery of the through hole 42 when viewed in the planar direction of the retractor 41, the friction caused by contact between the through hole vicinity 45 and the locked portion vicinity 46 increases to the extent that the slit width Wa is short.

[0091] 19 shows a state in which the portion 46 adjacent to the locked portion is pulled in the direction opposite to the insertion direction from the perpendicular insertion state shown in FIG. 18. The portion 46 adjacent to the locked portion is pulled toward the upper right in the figure. At this time, because the through-hole width W1 is shorter than the maximum width W2, the right end 43a of the first locked portion 43 and the right end 44a of the second locked portion 44 are close to or abut against the insertion-end side edge 42ab. Therefore, even in this pulled state, the locked portions 43, 44 are hooked around the periphery of the through-hole 42 and are thereby locked in the insertion direction.

[0092] The other configurations are the same as those in the first embodiment.

[0093] With the above configuration, when the retractor 41 is inserted in an oblique direction, the outward surface forms the side surface of an approximately disk having a center line in the up-down direction. Furthermore, when the retractor 41 is inserted in an orthogonal direction, the extension lines of the generatrixes at different positions in the longitudinal direction intersect or approach each other above the retractor 41, and the outward surface forms part of the side surface of an approximately truncated cone having a center line in the up-down direction and decreasing in diameter toward the top. Then, the retractor 41 in the assembled state into an approximately truncated cone shape is inserted into the body cavity starting from the side with the largest diameter, as shown in the schematic diagrams of Figures 6(a) and (b).

[0094] 19 , when the locked portion neighboring portion 46 is pulled in the direction opposite to the insertion direction, the first locked portion 43 and the second locked portion 44 approach or abut against the insertion-end side edge 42ab of the through-hole 42, and the locked portion neighboring portion 46 is locked in the insertion direction by the through-hole neighboring portion 45. The right end 43a of the first locked portion and the right end 44a of the second locked portion are positioned on a straight line in the width direction of the retractor 41. Therefore, when the locked portion neighboring portion 46 is pulled in the direction opposite to the insertion direction, the through-hole neighboring portion 45 can be locked with equal force against the first locked portion 43 and the second locked portion 44, respectively. This allows the retractor 41 to maintain a constant, approximately truncated cone shape while the locked portion neighboring portion 46 is locked in the insertion direction. The retractor 41 can then remain assembled in a stable configuration.

[0095] [Variations] Figure 20 shows a first modified example of the fourth embodiment of the retractor according to the present invention. In Figure 20, 411 is a retractor. Following the first modified example, second to sixth modified examples of the fourth embodiment are shown. Unless otherwise specified, the configurations of retractors 411 to 416 in these modified examples are the same as the configuration of retractor 41 in the present embodiment described above.

[0096] As shown in the development view of FIG. 20, the constricted portion 501 is recessed not adjacent to the first locked portion 431 near the center portion 471 but adjacent to the second locked portion 441 near the center portion 471.

[0097] As in this embodiment and the first modification, the constricted portion may be recessed on either the upper or lower side of the retractor.

[0098] Second and third modified examples are shown in Figures 21(a) and 21(b), respectively. In the second modified example, a lower end 472a of a central portion 472 of a retractor 412 forms a wavy portion. This wavy portion may be located on the lower side when the retractor 412 is used. The retractor 412 may also have wavy portions on both the upper and lower edges of Figure 21(a). In the third modified example of Figure 21(b), a retractor 413 similarly has a lower end 473a of a central portion 473 that forms a wavy portion.

[0099] The wavy portions in the second and third modified examples are wavy in the width direction of the retractors 412 and 413. The pitch of the wavy portions in the retractor 413 in the third modified example is longer than the pitch of the wavy portions in the second modified example.

[0100] Fourth and fifth modified examples are shown in Figures 22(a) and 22(b), respectively. In the fourth modified example, a lower end 474a of a central portion 474 of a retractor 414 forms an uneven portion. This uneven portion may be located on the lower side when the retractor 414 is used. Furthermore, the retractor 414 may have uneven portions on both the upper and lower edges of Figure 22(a). In the fifth modified example of Figure 22(b), a lower end 475a of a central portion 475 of a retractor 415 similarly forms an uneven portion.

[0101] The uneven portions in the fourth and fifth modified examples are uneven in the width direction of retractors 414, 415. Retractor 415 in the fifth modified example has a longer pitch of the uneven portions than the pitch of the uneven portions in the fourth modified example. The corners and edges of each uneven portion may be rounded to prevent damage to the affected area or its surroundings.

[0102] The retractors 412-415 have wavy or uneven portions on their lower edges. By inserting the retractors 412-415 through the wound opening so that the wavy or uneven edges are positioned deep within the body cavity, they can abut against the affected area or its surroundings. Because the wavy or uneven portions are undulating, the edges are less likely to slip against the affected area or its surroundings. Therefore, even when the retractors 412-415, which are configured to form a ring, attempt to expand further outward or contract inward, the resistance of the wavy or uneven portions from the affected area or its surroundings prevents rapid expansion or contraction. This allows the retractors 412-415 to be stabilized in a certain expanded state, maintaining a wide surgical field and a large surgical area within the body cavity. Moreover, it is difficult to move back and forth and left and right in a plan view, and surgery can be performed by placing the retractors 412 to 415 at a fixed position relative to the wound opening Ks.

[0103] A sixth modified example is shown in Figures 23(a) to (c). The vertical arrow T in Figures 23(b) and 23(c) indicates the thickness direction of the retractor 416. Figures 23(a) and 23(b) show a front view and a plan view, respectively, of the retractor 416 in an unfolded state, and Figure 23(c) shows a partially enlarged plan view of part A in Figure 23(b). In the sixth modified example, the retractor 416 in an unfolded state has a plurality of substantially rectangular quadrilateral portions 476c recessed facing backward on the front surface of the central portion 476. This retractor 416 can be assembled, for example, by bending the insertion end 496 (not shown) backward and then passing the insertion end 496 (not shown) through the through hole 426 to form a loop. The outer surface in the assembled state has each quadrilateral portion 476c recessed radially inward. The partial enlarged plan view of FIG. 23(c) shows a state in which a quadrilateral portion 476c is recessed in a surface 476d of the central portion 476 in the unfolded state.

[0104] Although not shown, each quadrilateral portion 476c' may be provided in a protruding position on a surface 476d' of the central portion 476' in the unfolded state, so that each quadrilateral portion 476c' protrudes radially outward in the assembled state.

[0105] With the configuration of the sixth modification, the retractor 416 has multiple quadrilateral portions 476c, 476c' on its outer surface when bent. Inserting the retractor 416 through the wound opening allows the quadrilateral portions 476c, 476c' to abut against the affected area or surrounding internal organs. At this time, because the quadrilateral portions 476c, 476c' are recessed or protruded on the outer surface, the central portion 476 experiences high friction with these areas, making it less likely to slip. Therefore, even if the retractor 476 attempts to expand, rotate, or move, the resistance of the quadrilateral portions 476c, 476c' from the affected area or surrounding internal organs prevents this. This stabilizes the shape, posture, and position of the retractor 476, allowing for a wide surgical field and a large surgical area within the body cavity.

[0106] It should be noted that a single retractor may be provided with multiple types of wavy portions, uneven portions, and quadrilateral portions exemplified in the second to sixth modified examples. For example, a wavy portion may be provided on one half of the longitudinal direction of the retractor, and a wavy portion with a longer pitch may be provided on the other half. Alternatively, a wavy portion may be provided on one half, and an uneven portion may be provided on the other half. Furthermore, a quadrilateral portion may be provided on the surface, and a wavy portion or uneven portion may be provided on the periphery.

[0107] [Fifth embodiment] A fifth embodiment of the present invention will be illustrated using Figures 24 to 27. Figure 24 shows a retractor 51 in an unfolded state. Retractor 51 has a through-hole 52 in the thickness direction formed in a portion near the right end in the longitudinal direction. Retractor 51 also has a first locked portion 53 facing downward in the figure and a second locked portion 54 facing upward in the same portion near the left end. The portion near the right end is also referred to as a through-hole vicinity 55, and the portion near the left end is also referred to as a locked portion vicinity 56.

[0108] The central portion sandwiched between through-hole vicinity 55 and locked portion vicinity 56 in the longitudinal direction is called central portion 57. Central portion 57 extends in the longitudinal direction, and its center line and both ends in the width direction are straight lines and parallel to each other. Of the ends in the width direction of retractor 51, the lower end is called lower end 57a, and the upper end is called upper end 57b.

[0109] FIG. 25 shows a partially enlarged view of the through hole 52. The through hole 52 has a first point 52a, located at the lower right of FIG. 25, and a second point 52b, located at the upper left, on the inner periphery of the through hole 52 on the side of the insertion end 58. The first point 52a is located closer to the lower end 57a, and the second point 52b is located closer to the upper end 57b. A linear insertion end edge 52ab of the through hole 52 extends between the first point 52a and the second point 52b. That is, a line segment connecting the first point 52a and the second point 52b runs along the insertion end edge 52ab. These line segments and the insertion end edge 52ab are inclined such that the first point 52a approaches the insertion end 58 and the second point 52b approaches the insertion end 59. W5 is a length equivalent to the height of the right-angled triangle in the fourth embodiment, and is also called the height of the right-angled triangle as in the fourth embodiment. In addition, the inserting end edge 52cd located to the left of the inserted end edge 52ab in FIG. 25 is formed in a substantially straight line in the width direction of the retractor 51.

[0110] Figure 26 shows an example of a state in which the insertion end 59 inserted into the through-hole 52 from the front of the retractor 51, which is the front of the figure, advances to the left in the figure, in the assembled state of the retractor 51. This figure is a photo of a prototype and a trace of that image. The retractor 51 in this figure is in an orthogonal insertion state. In the orthogonal insertion state of the retractor 51, the extension lines of the generatrixes at different positions in the longitudinal direction intersect or approach each other above the retractor 51, and the outward surface forms part of the side surface of a substantially truncated cone having a centerline in the approximately vertical direction and a diameter that decreases toward the upper side. Figure 26 shows this form.

[0111] In addition, in Figure 25, the second through-hole width W6, which is the width of the insertion end side edge 52cd located adjacent to the insertion end side edge 52ad of the through-hole 52, is shorter than the through-hole width W1, shorter than the normal width W4, and shorter than the right-angled triangle height W5.

[0112] In the orthogonal insertion state of Figure 26, the direction of the inserted end side edge 52ab is approximately the same as the width direction of the portion 56 near the engaged portion and the central portion 57 of the portion adjacent to it, and since the through hole width W1, which is the width of the through hole 52 in the direction of the inserted end side edge 52ab, is longer than the normal width W4, the portion 56 near the engaged portion and the central portion 57 of the portion adjacent to it can move in the insertion direction through the through hole 52.

[0113] The other configurations are the same as those of the fourth embodiment.

[0114] 27 shows a state in which the locked portion neighboring portion 56 is pulled in the direction opposite to the insertion direction from the perpendicular insertion state shown in FIG. 26. The locked portion neighboring portion 56 is pulled toward the upper right in the figure. At this time, because the through-hole width W1 is shorter than the maximum width W2, the first locked portion right end 53a of the first locked portion 53 and the second locked portion right end 54a of the second locked portion 54 approach or abut the insertion-end side edge 52ab. Therefore, even in this pulled state, the locked portions 53, 54 are hooked around the periphery of the through-hole 52 and are locked in the insertion direction. As a result, the locked portion neighboring portion 56 is locked in the insertion direction by the through-hole neighboring portion 55.

[0115] The right end 53a of the first locked portion and the right end 54a of the second locked portion are positioned on a straight line in the width direction of the retractor 51. Therefore, when the locked portion neighboring portion 56 is pulled in the direction opposite to the insertion direction, the through-hole neighboring portion 55 can be locked with equal force to the first locked portion 53 and the second locked portion 54, respectively. This allows the retractor 51 to maintain a state in which the locked portion neighboring portion 56 is locked in the insertion direction while maintaining a constant, approximately truncated cone shape. Thus, the retractor 51 can remain assembled in a stable form.

[0116] [Sixth embodiment] A sixth embodiment of the present invention will be illustrated using Figures 28 to 30. Figure 28 shows a retractor 61 in an unfolded state. The retractor 61 has a through-hole 62 in the thickness direction formed in a portion near the right end in the longitudinal direction. The retractor 61 also has a first locked portion 63 facing downward in the figure and a second locked portion 64 facing upward in the same portion near the left end. The portion near the right end is also referred to as a through-hole vicinity 65, and the portion near the left end is also referred to as a locked portion vicinity 66.

[0117] FIG. 29 shows a partially enlarged view of the through hole 62. The through hole 62 has a first point 62c, located at the lower right of FIG. 29, and a second point 62d, located at the upper left, on the inner periphery of the through hole 62 on the side of the insertion end 69. The first point 62c is located closer to the lower end 67a, and the second point 62d is located closer to the upper end 67b. A linear insertion end edge 62cd of the through hole 62 extends between the first point 62c and the second point 62d. That is, a straight line segment connecting the first point 62c and the second point 62d runs along the insertion end edge 62cd. These line segments and the insertion end edge 62cd are inclined such that the first point 62c approaches the receiving end 68 and the second point 62d approaches the insertion end 69. W5 is a length equivalent to the height of the right-angled triangle in the fifth embodiment, and is also called the height of the right-angled triangle as in the fifth embodiment. In addition, the inserted end side edge 62ab located immediately to the right of the inserting end side edge 62cd in FIG. 29 is formed in a substantially straight line in the width direction of the retractor 61.

[0118] FIG. 30 shows an example of a state in which the insertion end 69, inserted into the through-hole 62 from the front of the retractor 61 (the front of the figure) and moving toward the left of the retractor 61 (the left of the figure). This figure is a tracing of an image of a prototype. The insertion direction is approximately perpendicular to the direction of the insertion end side edge 62cd. The state of the retractor 61 in this figure is called the perpendicular insertion state. In the perpendicular insertion state, the retractor 61 has extensions of the generatrix lines at different positions in the longitudinal direction intersect or approach each other above the retractor 61, forming part of the side surface of an approximately truncated cone whose outward surface has a centerline in the approximately vertical direction and whose diameter decreases toward the top. FIG. 30 shows this form.

[0119] The second through-hole width W6, which is the width of the insertion end side edge 62ab, is shorter than the through-hole width W1, shorter than the normal width W4, and shorter than the right-angled triangle height W5.

[0120] In the orthogonal insertion state of Figure 30, the direction of the insertion end side edge 62cd is approximately the same as the width direction of the portion 66 near the engaging portion and the central portion 67 of the portion adjacent to it, and since the through hole width W1, which is the width of the through hole 62 in the direction of the insertion end side edge 62cd, is longer than the normal width W4, the portion 66 near the engaging portion and the central portion 67 of the portion adjacent to it can move through the through hole 62 in the insertion direction.

[0121] The other configurations are common to the fourth and fifth embodiments.

[0122] Figure 31 shows a state in which the locked portion neighboring portion 66 has been fully pulled in the direction opposite to the insertion direction from the perpendicular insertion state shown in Figure 30. By fully pulling, the assembled retractor 61 has rotated the locked portion neighboring portion 66 in the clockwise direction CL relative to the through-hole neighboring portion 65, changing to a diagonal insertion state in which the width direction of the locked portion neighboring portion 66 and the width direction of the through-hole neighboring portion 65 coincide. The locked portion neighboring portion 66 is then pulled to the right in the figure. That is, because the second through-hole width W6 is shorter than the maximum width W2, the first locked portion right end 63a of the first locked portion 63 and the second locked portion right end 64a of the second locked portion 64 are close to or abut against the insertion end side edge 62ab. When the second locked portion 64 approaches or abuts against the insertion end side edge 62ab, the locked portion neighboring portion 66 stops rotating in the clockwise direction CL. Even in this fully pulled state, the locked portions 63, 64 are hooked around the through-hole 62 and locked leftward. As a result, the locked portion neighboring portion 66 is locked leftward by the through-hole neighboring portion 65. When the locked portion neighboring portion 66 is fully pulled in the opposite direction to the insertion direction, the locked portion neighboring portion 66 rotates as described above, so the retractor 61 no longer has a generally frustum shape, but rather has an outward surface that forms a generally cylindrical side surface. If the locked portions 63, 64 are not locked by the through-hole 62, there is a concern that the retractor 61 may, in the worst case scenario, return to a rectangular plate shape inside the body cavity. Therefore, the configuration shown in FIG. 31 can prevent such a situation.

[0123] In this embodiment, the retractor 61 is fully pulled to the left and right, as shown in FIG. 31, causing the locking portion adjacent portion 66 to rotate and reach the diagonal insertion state. However, the dimensions may be determined so that the retractor is always in the perpendicular insertion state. 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 equal to or shorter than the normal width W4, making it impossible to achieve the diagonal insertion state in which the width direction of the through-hole adjacent portion 65 and the width direction of the locking portion adjacent portion 66 coincide. Therefore, the outward surface of the retractor 61 cannot form the side surface of a substantially cylinder.

[0124] 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.

[0125] 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.

[0126] In addition, although the figures show a configuration in which the constricted portion is recessed either upward or downward in the width direction, two constricted portions may be recessed on both sides in the width direction. As described above, the retractor of the present invention is used in an orientation that is convenient for the user, such as upward, downward, left, right, forward, or backward, so it is sufficient that the constricted portion is provided in such a convenient orientation.

[0127] The resin component may be any resin other than polyether ether ketone resin or polyphenylene sulfide resin, as long as it has chemical resistance.

[0128] Furthermore, for the sixth modified example of the fourth embodiment, an example of a substantially rectangular quadrilateral portion has been given, but when such a quadrilateral portion is applied to the retractors of the first to third embodiments, a substantially trapezoidal quadrilateral portion may be provided instead of the substantially rectangular quadrilateral portion, in accordance with the fact that the retractors of the first to third embodiments are formed in an arc shape having a width.

[0129] Furthermore, although an example has been given in which the right ends of the first and second locked portions are positioned on a straight line in the width direction of the retractor, the right ends do not need to be positioned on a straight line as long as the orientation of these adjacent portions is in the intended direction 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. [Industrial Applicability]

[0130] INDUSTRIAL APPLICABILITY The present invention can be used in a retractor for securing a surgical field and an operating area when a surgeon performs surgery on a human body. [Explanation of symbols]

[0131] 11,21,31,41,51,61,111,311,411,412,413,414,415,416 Retractor 11e, 21e Expanded diameter side 11s,21s Reduced diameter side 12,22,32,42,52,62,321,421 Through holes 13,23,33,43,53,63,431 1st locked part 13a, 43a, 53a, 63a 1st locked part right end 14,24,34,44,54,64,441 2nd locked part 14a, 44a, 54a, 64a 2nd locked part right end 15, 25, 35, 45, 55, 65, 151, 451 Near the through hole (near the first end) 16, 26, 36, 46, 56, 66, 161, 461 Near the locked portion (near the second end) 17,27,37,47,57,67,471,472,473,474,475,476 Central part 17a,27a,37a Outer edge 17b,27b,37b Inner edge 18, 28, 38, 48, 58, 68, 181, 481 Inserted end (first end) 19, 29, 39, 49, 59, 69, 191, 491 Insertion end (second end) 20,30,40,50,60,70,201,501 Neck 22a,42a,52a,62c,421a 1st point 22b,42b,52a,62d,421b 2nd point 22ab, 42ab, 52ab, 62ab, 421ab Inserted end edge 22c,42c,421c 3rd point 22d,42d,421d 4th point 22cd,42cd,52cd,62cd,421cd Insertion end edge 37c, 371c First protrusion 37d, 371d Second overhang 47a,57a,67a,472a,473a,474a,475a Lower end 47b,57b,67b Upper end 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 retractor that can be inserted partially or entirely into the patient's body to secure a surgical field and a surgical area, The material contains a synthetic resin that is chemical-resistant and elastic as its main resin component, and when developed into a plate, has a first end and a second end spaced apart from the first end and has a width direction, 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, and a through hole that can pass the second end is formed in a portion near the first end, and the diameter of the ring can be changed by changing the length of the distance that the second end is passed through the through hole, The formed ring has an outward surface that forms the side surface of a substantially circular truncated cone, and is inserted into the body cavity in order from the larger diameter side of the side surface. A retractor characterized by:

2. In the central portion sandwiched between the first end vicinity portion and the second end vicinity portion, the center line in the width direction forms an arc in the unfolded state. The retractor of claim 1 .

3. 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. The retractor of claim 2 .

4. The inner peripheral edge of the through hole has a shape having a line segment between two points, The line segment between the two points is inclined so that 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. The retractor of claim 1 .

5. The second end vicinity portion, which is in the vicinity of the second end, has a locked portion that protrudes in the width direction beyond the through hole when the second end is passed through the first end vicinity portion.

5. The retractor according to claim 1, wherein the retractor is a flexible member.

6. A pair of the engagement portions is provided, The respective engaged portions protrude outward in both directions in the width direction, At least the engaged portion provided on one side in the width direction is 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.

6. The retractor of claim 5.

7. When the ring is formed, the ring is configured to have a protruding portion that protrudes radially outward from the edge on the smaller diameter side of both end edges of the side surface.

5. The retractor according to claim 1, wherein the retractor is a flexible member.

Images