Stylet

Abstract

To provide a stylet in which a bending shape can be easily operated by an operator at the time of inserting or removing a tracheal tube to and from an air duct, for example.SOLUTION: A variable shaft part 23 included in a stylet 20 has a plurality of segments 30 including a first segment 30A and a second segment 30B which are adjacent to each other. The variable shaft part 23 is provided with a hinge structure 32 having a gap 32a between the segments 30A, 30B and a fulcrum 32b. The fulcrum 32b is composed of a first contact part 42 of the first segment 30A and a second contact part 45 of the second segment 30B. The second contact part 45 performs rolling motion with respect to the first contact part 42.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a stylet.

Background Art

[0002] In the medical field, a stylet is used to insert it into a flexible tube to stabilize the shape of the tube. As an example, there is a stylet for assisting tracheal tube intubation used for a tracheal tube. Specifically, for example, during general anesthesia, cardiopulmonary resuscitation, or before artificial respiration, a tracheal tube is inserted into a patient's trachea to secure the airway. The tracheal tube has a flexible tube with openings at both the tip and the base, and an inflatable cuff is provided on the outside near the tip. Such a tracheal tube is inserted from the patient's mouth into the airway, and air is supplied to and inflated in the cuff with the cuff positioned deeper than the glottis. As a result, the patient's lungs communicate with the outside through the internal space of the flexible tube, while the airway is blocked (filled) by the cuff outside the flexible tube. Then, the patient's breathing is managed by connecting a ventilator to the opening at the base of the flexible tube in this state.

[0003] Also, a person's glottis is in the larynx connecting the trachea and the pharynx, and the larynx is divided into an upper glottis closer to the outside and a lower glottis farther from the outside (closer to the lungs) with the glottis as the boundary. And there is an epiglottis in the upper glottis. Therefore, in the procedure of inserting the tracheal tube, it is necessary to guide the tip of the tube further into the glottis through the epiglottis. Thus, the tracheal tube is passed from the mouth through the larynx, and in the larynx, it passes through the epiglottis and the glottis in sequence. However, the shape of the airway from the mouth to the glottis of the larynx varies depending on the person and the posture, and generally curves in the middle. Therefore, in order to facilitate the insertion of the tracheal tube into the trachea, a stylet is used as a means to pre-curve the tracheal tube (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2006-527027 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] The stylet described in Patent Document 1 is made of a metal such as copper and is composed of a flexible rod. Therefore, the tracheal tube with the stylet inserted can be bent according to the airway shape of the patient before intubation. As a result, smooth intubation is expected.

[0006] However, it is not easy to accurately grasp the airway shape of the patient in advance. Therefore, during the insertion of the tracheal tube into the trachea, it may be found that the shape of the tracheal tube is not appropriate. In that case, the tracheal tube is withdrawn from the trachea, bent again, and then inserted again. However, such repeated insertions will result in a loss of precious time in emergency treatment and also impose a great burden on the patient.

[0007] On the other hand, there is a catheter as a long and flexible tube member that can be bent while being inserted into the body. Therefore, it is conceivable to apply the technology of the catheter to the stylet so that the tracheal tube can be bent by the operation of the operator while being inserted into the airway. However, the tracheal tube has a larger diameter than the catheter and higher rigidity to prevent kinking. Therefore, simply applying the technology of the catheter alone lacks practicality as a stylet for the tracheal tube. Also, such problems are not limited to the stylet for the tracheal tube but also apply to other stylets used by being inserted into a relatively rigid tube.

[0008] In addition, the patient's airway does not curve with a single diameter but has different degrees of curvature depending on the site (depth position). Therefore, the realization of a stylet that can be bent to suit the shape of the airway has become an issue.

[0009] Therefore, the present disclosure aims to solve at least one of the above-described problems, and provides a stylet that can easily manipulate the bending shape by an operator even for a relatively rigid tube, and a stylet that can be bent into a suitable shape according to the airway shape of a patient, among others.

Means for Solving the Problems

[0010] The stylet according to the first aspect of the present disclosure includes a variable shaft portion that is composed of a plurality of segments arranged in the axial direction and is bendable, and a wire that is provided so as to penetrate the plurality of segments in the axial direction and applies a compressive force in the axial direction for bending the variable shaft portion. The plurality of segments include a first segment and a second segment adjacent to the first segment on the tip side in the axial direction. The variable shaft portion is provided with a gap that allows the second segment to tilt with respect to the first segment when the variable shaft portion is bent, and a fulcrum when the second segment tilts with respect to the first segment. A hinge structure having the fulcrum is composed of a first contact portion of the first segment and a second contact portion of the second segment that contacts the first contact portion. When the second segment tilts with respect to the first segment by the compressive force, in the hinge structure, the first contact portion and the second contact portion roll relative to each other, and in the engagement structure, there is play in the axial direction.

[0011] Thus, when the stylet is inserted into the tube and the tube is operated, the tube can be easily bent. For example, even a tube with high rigidity such as a tracheal tube can be easily bent by using the above stylet. That is, in the case of the stylet according to the present disclosure, by operating so as to pull the wire passing through the plurality of segments, the adjacent segments are relatively displaced to bend the variable shaft portion. At this time, a pressing force acts on the adjacent segments. Therefore, if the adjacent segments are configured to slide when displaced, the frictional force generated at the sliding portion becomes a resistance and it becomes difficult to displace, and the variable shaft portion becomes difficult to bend. Moreover, since the tracheal tube has higher rigidity than the catheter, the stylet for the tracheal tube needs to pull the wire with a relatively large force. Then, a larger frictional force is generated between the segments, and an increasingly large force is required to bend the variable shaft portion.

[0012] On the other hand, the stylet according to the present disclosure is provided with play in the axial direction in the engagement structure between adjacent segments, and the fulcrum forming the hinge structure is composed of a first contact portion and a second contact portion where one rolls with respect to the other. With such a configuration, it is difficult for the position of the contact portion to shift between the first contact portion and the second contact portion, and since there is "play" in the axial direction in the engagement structure, friction is less likely to occur. As a result, the stylet according to the present disclosure can easily bend the variable shaft portion even with a small operating force, and can easily operate the bending shape even for a tube with high rigidity such as a tracheal tube.

[0013] Further, the stylet according to the second aspect of the present disclosure, in the first aspect, the gap may open toward one of the first radial directions which is the tilting direction of the second segment with respect to the first segment in the radial direction orthogonal to the axial direction, and the fulcrum may be located at the other end of the first radial direction in the gap.

[0014] As a result, the second segment is likely to tilt about the fulcrum with respect to the first segment. Therefore, the stylet according to the present disclosure can easily bend the tube even with a small operating force.

[0015] Further, in the first aspect of the stylet according to the third aspect of the present disclosure, the gap opens toward one side in a first radial direction, which is the tilting direction of the second segment with respect to the first segment among the radial directions orthogonal to the axial direction, and the fulcrum may be provided at a position on the other side of the first radial direction with respect to the axis and at a position where the second segment does not tilt with respect to the first segment by the force in the axial direction.

[0016] As a result, the second segment is likely to tilt about the fulcrum with respect to the first segment. Therefore, the stylet according to the present disclosure can easily bend the tube even with a small operating force.

[0017] Further, in the first aspect of the stylet according to the fourth aspect of the present disclosure, the engagement structure may include a separation prevention structure for preventing separation of the first segment and the second segment in the axial direction.

[0018] As a result, it is possible to prevent adjacent segments from separating in the axial direction without pulling the wire. Therefore, when the wire is pulled, the variable shaft portion can be bent with good responsiveness.

[0019] Further, in the fourth aspect of the stylet according to the fifth aspect of the present disclosure, the separation prevention structure may include an arm portion that extends from the tip of the first segment in the tip direction and bends and extends toward one side in a first radial direction, which is the tilting direction of the second segment with respect to the first segment among the radial directions orthogonal to the axial direction, and a hole portion formed in the second segment, in which the tip of the arm portion advances and retreats according to a change in the posture of the second segment with respect to the first segment.

[0020] As a result, when the variable shaft portion is curved, interference does not occur in the separation prevention structure, and when the shaft portion is linear, separation of adjacent segments can be prevented.

[0021] Further, in the stylet according to the sixth aspect of the present disclosure, in the fifth aspect, when the first contact portion and the second contact portion are in contact with each other by the compressive force in the axial direction in the hinge structure, the arm portion and the hole portion in the separation prevention structure may have play in the axial direction.

[0022] As a result, when the wire is pulled, axial contact is less likely to occur in the separation prevention structure. Therefore, the tube can be easily curved with a small operating force while preventing separation between adjacent segments.

[0023] Further, in the stylet according to the seventh aspect of the present disclosure, in the first aspect, the engagement structure may include an anti-torsion structure that prevents displacement of the first segment and the second segment around the axial direction.

[0024] As a result, torsion around the axial direction of each segment, that is, displacement in the rotational direction around the axis, can be prevented during operation or non-operation of the wire. Therefore, when the wire is pulled, the variable shaft portion can be curved in a desired direction.

[0025] Further, in the stylet according to the eighth aspect of the present disclosure, in the seventh aspect, the anti-torsion structure may include a first surface formed on the first segment and facing in a second radial direction orthogonal to the tilting direction of the second segment with respect to the first segment among the radial directions orthogonal to the axial direction, and a second surface formed on the second segment and provided to face the first surface in the second radial direction.

[0026] With such a twist prevention structure, when the variable shaft portion bends in a predetermined direction, there is no interference in the twist prevention structure. When the variable shaft portion attempts to bend in a direction other than the predetermined direction, the first surface and the second surface come into contact in the twist prevention structure, causing interference. Therefore, the twist of the variable shaft portion can be appropriately prevented.

[0027] Further, in the stylet according to the ninth aspect of the present disclosure, in the eighth aspect, the twist prevention structure includes a support wall provided on the first segment and having the first surface, and a recess provided on the second segment and having the second surface. When the first contact portion and the second contact portion are in contact with each other by the compressive force in the axial direction in the hinge structure, the support wall and the recess in the twist prevention structure may have a play in the axial direction.

[0028] Thereby, when the wire is pulled, axial contact is less likely to occur in the twist prevention structure. Therefore, while preventing separation between adjacent segments, the tube can be easily bent with a small operating force.

[0029] Further, in the stylet according to the tenth aspect of the present disclosure, in the first aspect, the wire may be provided only one through a position away from the fulcrum in the radial direction orthogonal to the axial direction.

[0030] Thereby, a configuration that enables the variable shaft portion to be bent can be simply realized. When operating with one wire, separation or twist may occur between adjacent segments. In that case, a configuration that also includes any of the separation prevention structures according to the fourth to sixth aspects described above, or any of the twist prevention structures according to the seventh to ninth aspects may be adopted.

[0031] Further, in the stylet according to the eleventh aspect of the present disclosure, in the first aspect, a flexible cover covering the variable shaft portion may be further provided.

[0032] This can prevent the plurality of segments from becoming separated. Also, in this case, for example, if a flexible cover made of a material with a small surface friction coefficient is used, the frictional resistance between the outer surface of the stylet (i.e., the outer surface of the flexible cover) and the inner surface of the tracheal tube can be reduced. Therefore, the tube can be easily bent with a smaller operating force.

[0033] Also, the stylet according to the 12th aspect of the present disclosure may be provided with a visible marker for discriminating the position of the variable shaft portion in the axial direction in the first aspect.

[0034] This makes it possible to visually confirm the bent portion of the stylet, making it easy to handle.

[0035] Also, the stylet according to the 13th aspect of the present disclosure further includes a tip shaft portion provided on the tip side in the axial direction with respect to the variable shaft portion, and composed of a plurality of segments arranged in the axial direction and penetrated by the wire. When a compressive force in the axial direction is applied by the wire, the change in curvature of the tip shaft portion may be smaller than the change in curvature of the variable shaft portion.

[0036] The stylet according to the 14th aspect of the present disclosure includes a first shaft portion composed of a plurality of segments arranged in the axial direction and capable of bending, a second shaft portion provided side by side with the first shaft portion in the axial direction and composed of a plurality of segments arranged in the axial direction, and a wire provided so as to penetrate each of the plurality of segments of the first shaft portion and the plurality of segments of the second shaft portion in the axial direction, and applying a compressive force in the axial direction for bending the first shaft portion. When a compressive force in the axial direction is applied by the wire, the change in curvature of the second shaft portion is smaller than the change in curvature of the first shaft portion.

[0037] The stylet according to the 15th aspect of the present disclosure includes a first shaft portion that is composed of a plurality of segments arranged in the axial direction and is bendable, a second shaft portion that is provided side by side with the first shaft portion in the axial direction and is composed of a plurality of segments arranged in the axial direction, and a wire that is provided so as to penetrate each of the plurality of segments of the first shaft portion and each of the plurality of segments of the second shaft portion, and applies a compressive force in the axial direction for bending the first shaft portion. Each of the plurality of segments of the first shaft portion and each of the plurality of segments of the second shaft portion includes a first segment and a second segment adjacent to the first segment on the tip side in the axial direction. The first shaft portion is provided with a hinge structure having a gap between the first segment and the second segment that allows the second segment to tilt with respect to the first segment when the first shaft portion is bent, and a fulcrum when the second segment tilts with respect to the first segment. The second shaft portion is not provided with the hinge structure or is provided with a hinge structure having a gap smaller than the gap of the first shaft portion.

[0038] Thereby, when inserting the tube, the tube can be deformed so that the second shaft portion is bent without bending the first shaft portion. Therefore, for example, when used for a tracheal tube, the tube can be deformed according to the curvature of the patient's trachea, making it easier to insert the tracheal tube into the patient's trachea. Further, since the second shaft portion is composed of a plurality of segments, a space is formed between adjacent segments in a state where the wire is loosened, and it can be slightly bent. Therefore, when pulling out the tracheal tube from the patient, by loosening the wire, the shape of the tracheal tube can be made to follow the shape of the patient's trachea, enabling smooth removal.

[0039] The stylet according to the 16th aspect of the present disclosure has a variable shaft portion having a plurality of segments arranged in the axial direction and configured to bend by tilting one of two adjacent segments with respect to the other, and a wire provided so as to penetrate the plurality of segments in the axial direction and apply a compressive force in the axial direction for bending the variable shaft portion. An engagement structure for engaging two adjacent segments among the plurality of segments is provided in the variable shaft portion. The segment has an overall cross-sectional shape in a plane including the axis that forms an S shape, an arm portion provided at one end in the axial direction and extending to the one side and curving in a first radial direction that is the tilting direction among the radial directions orthogonal to the axial direction, and a hole portion provided at the other end in the axial direction and extending in the first radial direction. The engagement structure includes the arm portion of one of the two adjacent segments and the hole portion of the other segment. The arm portion of one of the segments is inserted into the hole portion of the other segment with play, and the arm portion moves forward and backward with respect to the hole portion according to the change in posture during tilting.

[0040] Thus, between adjacent segments, the arm portion is inserted into the hole portion with play, and the arm portion moves forward and backward with respect to the hole portion according to the change in posture between the two segments. As a result, when the variable shaft portion bends, friction hardly occurs between adjacent segments, and it can be easily bent even when inserted into a highly rigid tracheal tube or the like.

Advantages of the Invention

[0041] According to the present disclosure, for example, a stylet that is suitably used when inserting and removing a tracheal tube into and from the airway and can be easily operated by an operator to change the bending shape, or a stylet that can be bent into a suitable shape according to the airway shape of a patient, can be provided.

Brief Description of the Drawings

[0042]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0043] (Embodiment 1) Hereinafter, the stylet according to Embodiment 1 of the present disclosure will be described by taking the one for assisting tracheal tube intubation as an example with reference to the drawings. However, the application target of the present disclosure is not limited to tracheal tubes and may be other tubes. Note that the concept of direction used in the following description is for convenience in explanation and does not limit the orientation of the configuration of each disclosure in that direction. Also, the holder described below is only one embodiment of the present disclosure. Therefore, the present disclosure is not limited to the following embodiments, and addition, deletion, or modification of the configuration is possible without departing from the spirit of the disclosure.

[0044] FIG. 1 is a schematic diagram showing a state of a tracheal intubation procedure using the stylet according to the present disclosure. As shown in FIG. 1, in tracheal intubation, the patient 1 is placed in a supine position with the chin raised (sniffing position). This is to make it easier to visually recognize the glottis 6 when inserting the tracheal tube 10 from the oral cavity 2 of the patient 1 to the depth of the glottis 6. By the way, there is an epiglottis 5 near the bifurcation of the esophagus 3 and the trachea 4 at the back of the oral cavity 2, and it is difficult to visually recognize the glottis 6 located behind the epiglottis 5 just by being in the sniffing position.

[0045] Therefore, in the tracheal intubation procedure, a laryngoscope 15 is used in combination. The laryngoscope 15 has a rod-shaped handle 16 and a blade 17 that bends and extends from the tip of the handle 16. The operator can hold the handle 16 and insert the blade 17 into the oral cavity, and by pressing near the base of the epiglottis 5, the epiglottis 5 can be opened. When the epiglottis 5 is opened, the glottis 6 can be visually recognized at the back, making it easier to insert the tracheal tube 10 into the depth of the glottis 6.

[0046] However, the airway that extends from the oral cavity 2 through the laryngeal mask 5 to the back of the glottis 6 is generally curved in the middle, and its curved shape varies depending on the patient and their posture. In order to smoothly insert the tracheal tube 10 into such a curved airway, a stylet 20 is used to pre-curve the tracheal tube 10 according to the airway shape in advance. The stylet 20 has an elongated rod shape, can be curved and maintain the curved state, and can curve the tracheal tube 10 by curving it while inserted into the tracheal tube 10. Note that the stylet 20 is inserted into the tracheal tube 10 and used during tracheal intubation, and is withdrawn from the tracheal tube 10 after intubation.

[0047] The tracheal tube 10 has a transparent tube body made of a synthetic resin such as polyvinyl chloride (PVC) or silicone, and an inflatable cuff 11 provided near the tip of the tube body. Furthermore, it has an inflation tube, a connector, etc. The dimensions of the tube body are such that the inner diameter is 5.0 mm or more and 10.0 mm or less (when including pediatric use, 2.0 mm or more and 10.0 mm or less), and the wall thickness is 1.0 mm or more and 2.2 mm or less (when including pediatric use, 0.5 mm or more and 2.2 mm or less), and can be arbitrarily selected considering the age and body type of the patient 1, etc.

[0048] Figure 2 is an external view and a cross-sectional view of the stylet 20. These external view and cross-sectional view show the state in which the stylet 20 is in a straight shape. The cross-sectional view shows the cut surface when the stylet 20 is cut in a plane including the direction along the axis A1 of the stylet 20 and the bending direction of the stylet 20. Hereinafter, the direction along the axis A1 is referred to as the front-rear direction, the bending direction (first diameter direction) of the stylet 20 is referred to as the up-down direction, and the direction intersecting the both (second diameter direction) is referred to as the left-right direction. Furthermore, the front side may be referred to as the tip side, and the rear side may be referred to as the base end side.

[0049] As shown in this Figure 2, the stylet 20 includes a shaft 21 and a wire 26 (the illustration of the wire 26 is omitted in the cross-sectional view). Further, the shaft 21 includes, in order from the proximal end side along its longitudinal direction, a proximal shaft portion 22, a variable shaft portion (first shaft portion) 23, a distal shaft portion 24 (second shaft portion), and a header 25. Among these, both the variable shaft portion 23 and the distal shaft portion 24 are each composed of a plurality of segments, and further, as will be described later, the variable shaft 23 can be curved in the vertical direction by the operation of the wire 26.

[0050] [1. Variable Shaft Portion] The variable shaft portion (first shaft portion) 23 is composed of a plurality of segments 30 arranged in the longitudinal direction. FIG. 3A is an enlarged view of a part IIIA of the appearance of the variable shaft portion 23 shown in FIG. 2, and FIG. 3B is an enlarged view of a part IIIB of the cross-section of the variable shaft portion 23 shown in FIG. 2. Further, FIG. 4A is a perspective view of the segment 30 when viewed from the distal end side, and FIG. 4B is a perspective view of the segment 30 when viewed from the proximal end side.

[0051] The plurality of segments 30 constituting the variable shaft portion 23 all have the same configuration in the present disclosure, and the overall cross-sectional shape when cut by a plane including the axis A1 forms, for example, an S-shaped (when viewed from the front side in FIG. 3B, it is an inverted S-shape, and when viewed from the back side, it is an S-shape) as shown in FIG. 3B. When distinguishing two adjacent segments 30, the segment 30 on the proximal end side may be referred to as segment 30A or the first segment 30A, and the segment 30 on the distal end side may be referred to as segment 30B or the second segment 30B (see FIG. 2).

[0052] When the segment 30 is viewed alone, as described above, the cross-sectional shape passing through the axis A1 forms an S shape and has an arm portion 50 and a hole portion 55, which will be described in detail later. And, among two adjacent segments 30, the arm portion 50 of one segment 30 is configured to be inserted into the hole portion 55 of the other segment 30 with play. Further, when the other segment 30 tilts with respect to one segment 30 so that the variable shaft portion 23 can be curved, the arm portion 50 is configured to move forward and backward with respect to the hole portion 55.

[0053] As shown in FIG. 4A and the like, the segment 30 includes a main body portion 31 having a substantially cylindrical shape. The outer shape of this main body portion 31 has a circular contour centered on the axis A1 when viewed along the front-rear direction. That is, the axis A1 is an axis passing through the center of the main body portion 31 of the segment 30. And, a through hole 40 in the front-rear direction through which the wire 26 is inserted is provided at a position offset downward from this center.

[0054] The segment 30 includes a hinge structure 32 for tilting the second segment 30B with respect to the first segment 30A, a separation prevention structure 33 for preventing separation of the first segment 30A and the second segment 30B in the front-rear direction, and a twist prevention structure 34 for preventing displacement of the first segment 30A and the second segment 30B around the axis A1 direction. Among these, the separation prevention structure 33 and the twist prevention structure 34 form an engagement structure for engaging the first segment 30A and the second segment 30B in the variable shaft portion 23.

[0055] [1-1. Hinge structure] As shown in FIG. 4A, a hinge surface 41 is provided at the front portion of the main body 31 in a range from a position above the center to the lower end of the main body 31. When viewed from the left - right direction, this hinge surface 41 forms a flat inclined surface where the lower end is located behind the upper end. The through - hole 40 described above opens forward on this hinge surface 41. Also, the upper - end portion of the hinge surface 41 forms a first contact portion 42 that contacts the adjacent segment 30B in front. This first contact portion 42 is located above the center through which the axis A1 passes in the main body 31.

[0056] A front support surface 43 is provided at a portion above the hinge surface 41 at the front portion of the main body 31. The front support surface 43 is approximately at the same position as the upper end of the hinge surface 41 in the front - rear direction and forms a flat surface orthogonal to the front - rear direction. Also, arm portions 50 extend from the left - right central positions of the front support surface 43 (to be described in detail later). Therefore, the front support surface 43 is substantially separated left and right by the arm portions 50. That is, the front support surface 43 has a left - hand front support surface 43L and a right - hand front support surface 43R with the arm portions 50 in between.

[0057] On the other hand, as shown in FIG. 4B, a facing surface 44 is provided at the rear portion of the main body 31 in a range from a position above the center to the lower end of the main body 31. When viewed from the left - right direction, this facing surface 44 forms a flat surface orthogonal to the front - rear direction. Also, the facing surface 44 has a certain length with left - right width dimensions smaller than the width dimension of the main body 31, and its width dimension is approximately the same as the width dimension of the hinge surface 41. Note that the through - hole 40 for the wire 26 described above opens rearward on this facing surface 44.

[0058] The upper end portion of the opposing surface 44 forms a second abutting portion 45 that abuts against a first abutting portion 42 of the adjacent segment 30A at the rear. This second abutting portion 45 is located above the center through which the axis A1 passes in the main body portion 31. Further, a rear support surface 46 that extends further upward from the upper end of the opposing surface 44 is provided at the rear portion of the main body portion 31. This rear support surface 46 includes two rear support surfaces 46L and 46R that extend from the left and right of the upper end of the opposing surface 44, respectively, and both are flush with and parallel to the opposing surface 44.

[0059] Here, the hinge surface 41 and the opposing surface 44 described above, and the first abutting portion 42 and the second abutting portion 45 constitute the hinge structure 32 of the variable shaft portion 23. That is, the space between the hinge surface 41 and the opposing surface 44 is between the first segment 30A and the second segment 30B, and forms a gap 32a that allows the second segment 30B to tilt with respect to the first segment 30A (see FIG. 3B). Further, the first abutting portion 42 and the second abutting portion 45 form a fulcrum 32b when the second segment 30B tilts with respect to the first segment 30A (see FIG. 3B).

[0060] Specifically, when the variable shaft portion 23 is linear, the segments 30A and 30B adjacent to each other in the front and rear have the front support surface 43 and the rear support surface 46 that face each other in contact. That is, the left front support surface 43L and the rear support surface 46L are in contact, and the right front support surface 43R and the rear support surface 46R are in contact. These front support surface 43 and rear support surface 46 are both flat surfaces orthogonal to the axis A1 as described above. Therefore, when they are in contact, the segments 30A and 30B have their axes A1 aligned with each other and the variable shaft 23 is linear (see the upper figure in FIG. 5). Note that when the variable shaft portion 23 is linear, the first abutting portion 42 and the second abutting portion 45 that form the fulcrum 32b are also in contact with each other.

[0061] Also, at this time, a gap 32a is formed between the segments 30A and 30B, between the hinge surface 41 and the opposing surface 44. When viewed from the left - right direction, this gap 32a has a wedge shape that opens downward, with the separation dimension between the hinge surface 41 and the opposing surface 44 increasing as it goes downward (see Fig. 3B). Also, as described above, the wire 26 passes through the through - hole 40 that opens at the hinge surface 41 and the opposing surface 44. Therefore, when the wire 26 is pulled to apply a compressive force in the direction of the axis A1 to the segments 30A and 30B, the second segment 30B tilts around the fulcrum 32b so as to narrow the gap 32a with respect to the first segment 30A (see the lower figure in Fig. 5).

[0062] Thus, the variable shaft portion 23 of the present disclosure includes a hinge structure 32 having a gap 32a and a fulcrum 32b between adjacent segments 30A and 30B. And the segments 30A and 30B can tilt (be relatively displaced) so that the gap 32a becomes smaller (the opposing surface 44 approaches the hinge surface 41) or the gap 32a becomes larger (the opposing surface 44 moves away from the hinge surface 41) around the fulcrum 32b. As a result, as shown in Fig. 5, the variable shaft portion 23 can be arbitrarily deformed according to the operation amount of the wire 26 between the linear state where the front support surface 43 and the rear support surface 46 are in contact (the upper figure in Fig. 5) and the maximum curved state where the hinge surface 41 and the opposing surface 44 are in contact (the lower figure in Fig. 5).

[0063] Also, at the above - mentioned fulcrum 32b, when the segments 30A and 30B are relatively displaced in the tilting direction, the second contact portion 45 rolls with respect to the first contact portion 42. That is, when the segments 30A and 30B are tilt - displaced, the contact point between the first contact portion 42 and the second contact portion 45 moves moment by moment, but a misalignment is less likely to occur between one contact location and the other contact location in contact with it. For example, it is not a pivot - support structure such that one forms a shaft and the other forms a bearing (in this case, misalignment occurs at the contact location between the outer peripheral surface of the shaft and the inner peripheral surface of the bearing).

[0064] Therefore, when the second segment 30B tilts with respect to the first segment 30A, the first contact portion 42 and the second contact portion 45 are relatively difficult to slide. Thus, it can be said that the first contact portion 42 and the second contact portion 45 contact each other in a manner that is difficult to slide when the segments 30A and 30B tilt. As a result, it is difficult for friction that provides resistance to tilting to occur between the first contact portion 42 and the second contact portion 61, and the second segment 30B can easily tilt with respect to the first segment 30A.

[0065] Also, as will be described later, the first segment 30A and the second segment 30B are engaged with each other with play in the direction of the axis A1 in the engagement structure (the separation prevention structure 33 and the twist prevention structure 34). Therefore, when a compressive force in the direction of the axis A1 acts between the segments 30A and 30B due to the operation of the wire 26, the first contact portion 42 and the second contact portion 45 that form the fulcrum 32b contact each other, while the other portions are difficult to contact each other in a direction along the axis A1. Such a configuration is also one of the reasons why it is difficult for friction that provides resistance to tilting to occur even when a compressive force acts between the segments 30A and 30B.

[0066] Further, in the hinge structure 32, the fulcrum 32b is located at the upper end of the gap 32a. Furthermore, the fulcrum 32b is located above the axis A1 and is provided at a position where the second segment 30B does not tilt with respect to the first segment 30A due to a force in the front-rear direction. Therefore, when the wire 26 is pulled, the second segment 30B can be tilted with respect to the first segment 30A with a smaller operating force.

[0067] In the above description, on the hinge surface 41 and the opposing surface 44 that form the gap 32a, only the hinge surface 41 is an inclined surface, but both the hinge surface 41 and the opposing surface 44 may be inclined surfaces, or only the opposing surface 44 may be an inclined surface. That is, the hinge surface 41 and the opposing surface 44 only need to form the gap 32a that allows the second segment 30B to tilt with respect to the first segment 30A, and may have a surface shape other than a flat surface such as a curved surface.

[0068] Furthermore, here, although the gaps 32a between adjacent segments 30A and 30B constituting the variable shaft portion 23 have the same shape, the dimensions of the gaps 32a (for example, the separation distance between the hinge surface 41 and the opposing surface 44) may be partially different. For example, the gap 32a between segments 30 located on the distal end side of the variable shaft portion 23 may be configured such that the separation distance between the hinge surface 41 and the opposing surface 44 is larger than the gap 32a between segments 30 located on the proximal end side, or vice versa.

[0069] [1-2. Separation prevention structure] Next, the separation prevention structure 33 forming the engagement structure will be described. An arm portion 50 is provided at the front portion of the main body portion 31. That is, as shown in FIG. 4A, the arm portion 50 extends downward in a curved manner from the left-right central portion (i.e., between the left and right front support surfaces 43L and 43R) of the front support surface 43 which is the tip portion of the main body portion 31 as it goes forward. As shown in FIG. 3B, when viewed from the left-right direction, the arm portion 50 forms an arc shape with a central angle of 90 degrees. And the tip 51 of the arm portion 50 is at the vertical center position of the main body portion 31 or at a position below the center.

[0070] As shown in FIGS. 4A and 4B, the left and right side surfaces 52 of the arm portion 50 form flat surfaces orthogonal to the left-right direction. In other words, the side surfaces 52 are planes parallel to the vertical direction which is the bending direction of the variable shaft portion 23. The outer surface 53 of the arm portion 50 forms a curved surface that smoothly continues from the upper portion of the outer peripheral surface of the main body portion 31 forward and further extends downward. Also, the inner surface 54 of the arm portion 50 forms a curved surface that extends forward from the upper end of the hinge surface 41 and further extends downward (see FIG. 3B).

[0071] On the one hand, as shown in FIG. 4B, a hole 55 into which an arm 50 of an adjacent segment 30A is inserted is provided at the rear of the main body 31. By inserting the arm 50 of the rear first segment 30A into the hole 55 of the front second segment 30B, the adjacent segments 30, 30 are connected (engaged) with each other and separation in the direction of the axis A1 is prevented.

[0072] Specifically, the hole 55 has a rear opening 55a that opens rearward between the left and right rear support surfaces 46L and 46R, and curves downward and extends forward from this rear opening 55a. The left and right side surfaces 56 of the hole 55 form flat surfaces orthogonal to the left - right direction. In other words, the side surfaces 56 are also planes parallel to the up - down direction, which is the bending direction of the variable shaft portion 23. And the left - right width dimension of the hole 55 is substantially the same as or slightly larger than the width dimension of the arm 50.

[0073] Also, the hole 55 has an upper opening 55b that opens upward at the upper part of the main body 31. This upper opening 55b is an opening that extends forward from between the left and right rear support surfaces 46L and 46R. The rear end of the upper opening 55b is connected to the upper end of the rear opening 55a, forming a continuous opening (see FIG. 4B).

[0074] As shown in FIG. 3B, the front surface 57 of the hole 55 forms a flat surface that extends downward from the front end of the upper opening 55b and is a plane orthogonal to the front - rear direction. The bottom surface 58 of the hole 55 is a surface that extends rearward from the front surface 57 and has a shape that matches the tip 51 of the arm 50. Also, the rear surface 59 of the hole 55 is a curved surface that extends upward from the bottom surface 58 and curves upwardly to reach the rear opening 55a, and has a shape that matches the inner surface 54 of the arm 50. Thus, the hole 55 is configured such that the opening area increases upward.

[0075] The above-described arm portion 50 and hole portion 55 form a separation prevention structure 33 (one of the engagement structures) according to the present disclosure. More precisely, the separation prevention structure 33 is constituted by the arm portion 50 of the rear first segment 30A and the hole portion 55 of the front second segment 30B.

[0076] In this separation prevention structure 33, according to the relative posture change of the segments 30A and 30B, the tip of the arm portion 50 of the first segment 30A advances and retreats with respect to the hole portion 55 of the second segment 30B. That is, when the variable shaft portion 23 is in a linear state as shown in the upper diagram of FIG. 5, the arm portion 50 has entered to the innermost part of the hole portion 55. For example, the tip 51 of the arm portion 50 abuts against the bottom surface 58 of the hole portion 55. Also, when the variable shaft portion 23 is in a curved state as shown in the lower diagram of FIG. 5, the arm portion 50 retreats slightly from the innermost part of the hole portion 55, and the tip 51 of the arm portion 50 is positioned at a distance from the bottom surface 58 of the hole portion 55 and has a gap compared to when it is in the linear state. At this time, a gap is also formed between the upper part (the recessed part) of the inner surface 54 of the arm portion 50 and the upper part (the protruding part) of the rear surface 59 of the hole portion 55. In this way, the separation prevention structure 33 does not prevent the posture change of the segments 30A and 30B in the tilting direction.

[0077] On the other hand, the separation prevention structure 33 restricts the separation of the segments 30A and 30B in the axial direction A1. That is, as shown in FIG. 5, in any state between when the variable shaft portion 23 is in a linear state (upper diagram) and the maximum curved state (lower diagram), at least a part of the inner surface 54 of the arm portion 50 of the first segment 30A and the rear surface 59 of the hole portion 55 of the second segment 30B face each other in the axial direction A1 of the first segment 30A. Therefore, when the segments 30A and 30B attempt to separate in the axial direction A1, the inner surface 54 and the rear surface 59 come into contact and interfere with each other, so the separation in the axial direction A1 is restricted.

[0078] By the way, when the wire 26 is pulled, a compressive force in the direction of the axis A1 acts on the adjacent segments 30A and 30B, and the first contact portion 42 and the second contact portion 45 forming the fulcrum 32b are in contact with each other (hereinafter, also referred to as the "compressed state"). The anti-separation structure 33 of the present disclosure is configured such that, in this compressed state, the surfaces facing each other in the direction of the axis A1 in the arm portion 50 and the hole portion 55 are difficult to contact each other. That is, there is a play in the direction of the axis A1 between the arm portion 50 and the hole portion 55, and they are engaged with each other.

[0079] Specifically, the dimension of the portion of the arm portion 50 inserted into the hole portion 55 in the direction of the axis A1 is smaller than the dimension of the portion of the hole portion 55 into which the arm portion 50 is inserted in the direction of the axis A1. As a result, the above-mentioned play is formed between the arm portion 50 and the hole portion 55. Further, the inner surface 54 of the arm portion 50 and the rear surface 59 of the hole portion 55 facing this in the direction of the axis A1 are separated from each other in the direction of the axis A1 in the compressed state. Also, the outer surface 53 of the arm portion 50 and the front surface 57 of the hole portion 55 facing this in the direction of the axis A1 are separated from each other in the direction of the axis A1 in the compressed state. With such a configuration, when the segments 30A and 30B are tilted and displaced, the segments 30A and 30B are in a compressed state, but due to the presence of the play, the arm portion 50 and the hole portion 55 are loosely fitted with each other in the direction of the axis A1, so that frictional resistance that hinders the tilting displacement is unlikely to occur between the opposing surfaces described above. Therefore, the variable shaft portion 23 can be easily bent.

[0080] [1-3. Anti-torsion structure] Next, the anti-torsion structure 34 forming the engagement structure will be described. As shown in FIG. 4A, a support wall 60 having a predetermined thickness in the left-right direction and extending forward is provided on the front portion of the main body portion 31 and outside the hinge surface 41. This support wall 60 has a semi-circular shape protruding forward when viewed from the left-right direction, is provided so as to coincide with the vertical center position of the main body portion 31, and has a vertical dimension of 1 / 4 to 1 / 3 of the vertical dimension of the main body portion 31. For example, the upper end of the support wall 60 is located at the same level as or slightly above the upper end of the hinge surface 41, and the lower end of the support wall 60 is located near the center of the opening of the through hole 40.

[0081] Further, the outer surface 61 of the support wall 60 forms a curved surface (arc surface) that smoothly continues from the outer surface of the main body portion 31. When viewed from the front, the contour of the outer surface 61 of the support wall 60 coincides with the outer peripheral surface of the main body portion 31. On the other hand, the inner surface 62 of the support wall 60 forms a flat surface orthogonal to the left-right direction. In other words, the inner surface 62 is a plane parallel to the up-down direction, which is the bending direction of the variable shaft portion 23. Also, the wall surface 60a connecting the outer surface 61 and the inner surface 62 has a curved surface shape that forms an arc protruding forward.

[0082] On the other hand, as shown in FIG. 4B, recesses 63 for accommodating the support walls 60 of the adjacent segments 30 are provided on the left and right of the rear portion of the main body portion 31 and on the opposing surface 44. These recesses 63 are recessed from the outer side in the left-right direction toward the inner side, and the outer surface 64 facing the outer side in the left-right direction forms a flat surface orthogonal to the left-right direction. In other words, the outer surface 64 is a plane parallel to the up-down direction, which is the bending direction of the variable shaft portion 23.

[0083] When viewed from the left-right direction, this outer surface 64 has a shape in which an upper rectangular portion and a lower sector portion with a central angle of 90 degrees are connected vertically. Therefore, the recess 63 also has a shape that opens upward such that the dimension in the direction of the axis A1 increases as it goes upward when viewed from the left-right direction. The lower sector portion of the outer surface 64 substantially matches the lower half of the support wall 60 that forms a semi-circular shape in terms of shape and dimensions. Also, a wall surface 63a stands upright from the edge portion extending from the front side to the lower side of the outer surface 64 toward the left and right outer sides.

[0084] The inner surface 62 of the above-described support wall 60 forms the first surface of the anti-torsion structure 34 according to the present disclosure, and the outer surface 64 of the recess 63 forms the second surface of the anti-torsion structure 34 according to the present disclosure. That is, when the front and rear segments 30A and 30B are connected, the left and right support walls 60 fit into the left and right recesses 63. At this time, the inner surface 62 of the left support wall 60 faces the outer surface 64 of the left recess 63, and the inner surface 62 of the right support wall 60 faces the outer surface 64 of the right recess 63. The opposing inner surface 62 and the screen 64 are both orthogonal to the left-right direction and are parallel to each other.

[0085] With such a configuration, the anti-torsion structure 34 composed of the support wall 60 and the recess 63 prevents the front and rear adjacent segments 30A and 30B from rotating (twisting) around the axis A1. Further, the anti-torsion structure 34 also restricts the second segment 30B from tilting in the left-right direction with respect to the first segment 30A.

[0086] Incidentally, as described above, in the anti-torsion structure 34, the inner surface 62 forming the first surface and the outer surface 64 forming the second surface are flat surfaces orthogonal to the left-right direction. Therefore, in the anti-torsion structure 34 of the present disclosure, when the adjacent segments 30A and 30B are in a compressed state, the inner surface 62 and the outer surface 64 are unlikely to come into contact in the direction of the axis A1. Also, the wall surface 65 of the recess 63 and the front surface of the support wall 60 facing it are also unlikely to come into contact in the direction of the axis A1. Therefore, even when the segments 30A and 30B are displaced by tilting and are in a compressed state, it is difficult to generate a frictional resistance that increases in response to the force in the direction of the axis A1. Therefore, the variable shaft portion 23 can be easily bent.

[0087] Furthermore, even when the wire 26 is in a compressed state where it is pulled, the support wall 60 and the recess 63 engage with a play in the direction of the axis A1. That is, in the anti-torsion structure 34, the wall surface 60a of the support wall 60 and the wall surface 63a of the recess 63 face each other in the direction of the axis A1. However, as shown in FIG. 3A, these wall surfaces 60a, 63a are spaced apart from each other in the direction of the axis A1 and have a play. Therefore, in the anti-torsion structure 34, when the variable shaft portion 23 is bent, it is difficult for frictional resistance that hinders the tilting displacement of the segment 30 to occur, and the variable shaft portion 23 can be easily bent.

[0088] Note that the arm portion 50 and the hole portion 55 described as the anti-separation structure 33 also function as the anti-torsion structure 34.

[0089] Specifically, when the front and rear segments 30A, 30B are connected, the left and right side surfaces 52 of the arm portion 50 of the first segment 30A face the left and right side surfaces 56 of the hole portion 55 of the second segment 30B, respectively. Further, both the side surface 52 and the side surface 56 form flat surfaces orthogonal to the left-right direction. Therefore, the side surface 52 of the arm portion 50 forms the first surface of the anti-torsion structure 34 according to the present disclosure, and the side surface 56 of the recess 55 forms the second surface of the anti-torsion structure 34 according to the present disclosure.

[0090] In this way, the anti-torsion structure 34 composed of the arm portion 50 and the hole portion 55 also prevents the front and rear adjacent segments 30A, 30B from rotating (twisting) around the axis A1, and also restricts the second segment 30B from tilting in the left-right direction with respect to the first segment 30A.

[0091] [2. Tip Shaft Portion] The tip shaft portion (second shaft portion) 24 is provided on the tip side (front side) in the direction of the axis A1 with respect to the variable shaft portion 23 described above, and is composed of a plurality of segments 70 arranged in the front-rear direction and penetrated by the wire 26. When a compressive force in the direction of the axis A1 is applied to the tip shaft portion 24 by the wire 26, the change in its curvature is smaller than the change in curvature of the variable shaft portion 23 (including the case where the bending change is zero).

[0092] FIG. 6A is a perspective view of the segment 70 as viewed from the tip side, and FIG. 6B is a perspective view of the segment 70 as viewed from the base end side. As can be seen from FIGS. 6A and 6B, the segment 70 has the same configuration at the rear part as the segment 30 that constitutes the variable shaft portion 23. Therefore, the foremost segment 30 and the rearmost segment 70 are connected in the same manner as the adjacent segments 30A and 30B in the front-rear direction.

[0093] On the other hand, the segment 70 and the segment 30 have the same configuration in most parts even at the front part, but some configurations are different. Therefore, below, the differences between the segment 70 and the segment 30 will be described. In FIGS. 6A and 6B, the same reference numerals are given to the configurations corresponding to the segment 30 in the segment 70.

[0094] The segment 70 does not have a hinge structure 32 like the segment 30. That is, a front support surface 71 is provided in the front part of the main body portion 31 of the segment 70 in the range from the upper end to the lower end. This front support surface 71 is formed in a region combining the front support surface 43 and the hinge surface 41 in the segment 30, and forms a flat surface orthogonal to the front-rear direction. Therefore, the front support surface 71 of the rear segment 70 is parallel to and faces the opposing surface 44 and the rear support surface 46 at the rear part of the front segment 70.

[0095] Therefore, there is no wedge-shaped gap 32a like the variable shaft portion 23 between the adjacent segments 70 before and after, and the hinge structure 32 is not formed. Regarding the other configurations of the segment 70, they are the same as the corresponding portions of the segment 30 already described, and the segment 70 is also provided with a separation prevention structure 33, a twist prevention structure 34, and the like.

[0096] The distal shaft portion 24 according to the present disclosure has a configuration in which a plurality of such segments 70 are connected. Thereby, when the wire 26 is pulled, even if the variable shaft portion 23 is curved, the distal shaft portion 24 can maintain a straight state. Therefore, it is possible to curve the middle portion while maintaining the distal end portion of the tracheal tube 10 in a straight state during intubation or the like.

[0097] On the other hand, when the pulling operation of the wire 26 is released, the front and rear segments 70 can be relatively displaced within the dimensional range of the separation prevention structure 33 (within the clearance range between the arm portion 50 and the hole portion 55). Therefore, when removing the tracheal tube 10, not only the variable shaft portion 23 but also the distal shaft portion 24 can be deformed so as to follow the shape of the trachea 4 of the patient 1.

[0098] Also, in the above, the distal shaft portion (second shaft portion) 24 is shown as a configuration having no hinge structure 32, but it is not limited to this. The second shaft portion may have a configuration in which the change in curvature is smaller than that of the first shaft portion. Therefore, it may have a gap 32a composed of the hinge surface 41 and the opposing surface 44. In this case, the gap 32a of the hinge structure 32 of the second shaft portion is configured to be smaller than the gap 32a of the hinge structure 32 of the first shaft portion. Thereby, when a compressive force in the direction of the axis A1 is applied by operating the wire 26, the change in curvature of the second shaft portion is smaller than the change in curvature of the first shaft portion.

[0099] [3. Header] The header 25 is provided on the tip side (front side) in the direction of the axis A1 with respect to the above-described tip shaft portion 24, and constitutes the tip of the shaft 21. FIG. 7A is a perspective view of the header 25 when viewed from the tip side, and FIG. 7B is a perspective view of the header 25 when viewed from the base end side. As can be seen from FIGS. 7A and 7B, the header 25 has the same configuration at the rear as that of the segment 70 (the same as the configuration at the rear of the segment 30). Therefore, the foremost segment 70 and the head 25 are connected in the same manner as the adjacent segments 70, 70 in the front-rear direction.

[0100] On the other hand, the header 25 and the segment 70 (or the segment 30) are different in the configuration at the front. Therefore, hereinafter, the differences between the header 25 and the segment 30 will be described. In FIGS. 7A and 7B, the same reference numerals are given to the configurations corresponding to the segment 30 in the header 25.

[0101] On the front part of the header 25, there are no hinge surfaces 41, arm portions 50, support walls 60, etc. like those of the segment 30, but a single tip surface 72 is provided. This tip surface 72 is a circular flat surface extending over the entire area of the front end of the header 25 and forms a plane orthogonal to the direction of the axis A1. And the through hole 40 penetrating the header 25 in the front-rear direction opens forward on this tip surface 72. The tip portion of the wire 26 provided through each part of the shaft 21 is fixed at the header 25 using an appropriate locking tool.

[0102] [4. Base end shaft portion] The base end shaft portion 22 is provided on the base end side (rear side) in the direction of the axis A1 with respect to the above-described variable shaft portion 23, and constitutes the base end of the shaft 21. FIG. 8A is a perspective view of the base end shaft portion 22 when viewed from the tip side, and FIG. 8B is a perspective view of the base end shaft portion 22 when viewed from the base end side.

[0103] As shown in FIGS. 8A and 8B, the proximal shaft portion 22 has a substantially columnar main body portion 73 that is elongated in the front-rear direction. The front portion of this main body portion 73 has the same configuration as the front portion of the segment 30 of the variable shaft portion 23. Therefore, the rearmost segment 30 and the proximal shaft portion 22 are connected in the same manner as the adjacent segments 30A and 30B. In FIGS. 8A and 8B, the same reference numerals are given to the configurations corresponding to the segment 30 in the proximal shaft portion 22.

[0104] On the other hand, on the rear portion of the proximal shaft portion 22, there are no opposing surfaces 44, rear support surfaces 46, hole portions 55, recessed portions 63, etc. like those of the segment 30. As shown in FIGS. 8A and 8B, the main body portion 73 of the proximal shaft portion 22 has a large-diameter cylindrical portion 74 located relatively on the front side and a small-diameter cylindrical portion 75 located on the rear side thereof. The large-diameter cylindrical portion 74 and the small-diameter cylindrical portion 75 are concentric, and a through-hole 40 is provided so as to penetrate both of them in the front-rear direction.

[0105] In the large-diameter cylindrical portion 74, the through-hole 40 opens in two directions, forward and backward. In contrast, in the small-diameter cylindrical portion 75, the through-hole 40 opens not only forward and backward but also downward.

[0106] To such a proximal shaft portion 22, in the small-diameter cylindrical portion 75 of the main body portion 73, it can be connected to an appropriate operating tool. The proximal end of the wire 26 is connected to the operating tool, and when the operator operates the operating tool, the wire 26 passing through the through-hole 40 of the shaft 21 is pulled or the wire 26 is loosened.

[0107] [5. Operation and Function of the Stylet] When the stylet 20 including the shaft 21 and the wire 26 as described above is operated to pull the wire 26, a compressive force in the direction of the axis A1 is applied to each part of the shaft 21 including the segments 30, 70, etc. As a result, the variable shaft portion 23 having the hinge structure 32 is curved in the vertical direction by the adjacent segments 30 tilting and displacing so as to narrow the gap 32a as described above.

[0108] Also, as can be seen from FIG. 5, in the hinge structure 32 provided in the variable shaft portion 23, when tilting displacement occurs, the first contact portion 42 and the second contact portion 45 that constitute the fulcrum 32b roll relative to each other. In other words, the first contact portion and the second contact portion contact each other in a manner that is difficult to slide relative to each other. That is, it is difficult to slide in the tilting direction. Therefore, friction that serves as resistance to tilting displacement is less likely to occur, and the stylet 20 can be easily bent. Moreover, since the adjacent segments 30A and 30B engage with a play in the direction of the axis A1 in the separation prevention structure 33 and the twist prevention structure 34 that form an engagement structure, friction that serves as resistance to tilting displacement is even less likely to occur, and the operation of the stylet 20 is even easier.

[0109] In particular, since the stylet 20 is used, for example, by being inserted into the highly rigid tracheal tube 10, a relatively strong operating force is required to pull the wire 26. If the fulcrum 32b has a configuration having a sliding surface composed of a shaft and a bearing, etc., due to the strong operating force in the direction of the axis A1, the sliding frictional force increases, making it difficult to bend the stylet 20, and an even stronger operating force is required. On the other hand, since the stylet 20 according to the present disclosure has a rolling type in which the fulcrum 32b is difficult to slide as described above, such difficulties do not occur, and it is possible to bend with a relatively small operating force.

[0110] Also, the stylet 20 is configured to be operated by a single wire 26 passed through a position eccentric from the center away from the fulcrum 32b. In this way, since the stylet 20 is realized with a simple configuration, manufacturing and assembly are easy, and malfunctions such as failures are less likely to occur, and a long service life can be expected. On the other hand, when the wire 26 is made into one in this way, separation and twisting of adjacent segments 30, 30 or segments 70, 70, etc. can occur. However, since the stylet 20 of the present disclosure is provided with the separation prevention structure 33 and the twist prevention structure 34, such separation and twisting are prevented.

[0111] In addition, the variable shaft portion 23 and the tip shaft portion 24 of the present disclosure are easily assembled and disassembled for each segment 30, 70, particularly due to the configuration of the engagement structure. Specifically described, in the separation prevention structure 33, as already described, the hole portion 55 is configured such that the upward opening area increases from the innermost bottom surface 58 toward the upper opening 55b (there is no portion where it becomes smaller in the middle). Further, in the anti-torsion structure 34, the recess 63 has an upwardly open shape. Therefore, taking the variable shaft portion 23 as an example, while bringing the rear segment 30A closer to the front segment 30B from above, align the support wall 60 with the recess 63, and insert (engage) the arm portion 50 into the hole portion 55, and the two segments 30A and 30B can be assembled. Conversely, they can be disassembled by reversing the operation. As a result, the stylet 20 after use can be disassembled and easily cleaned, and the number of segments 30 constituting the stylet 20 can be easily adjusted.

[0112] As can also be seen from FIGS. 4A, 4B, 6A, 6B, 7A, 7B, 8A, and 8B, the corners forming the connection portions between the surfaces of the above-described respective portions are chamfered. The corners of the portions forming the engagement structure and engaging with each other, such as the arm portion 50 and the hole portion 55, and the support wall 60 and the recess 63, are chamfered. Thereby, for example, the posture displacement of the adjacent segments 30A and 30B is smoothed, and the assembly work becomes easy. Further, in the above, the configuration in which the arm portion 50 is provided at the front portion of the main body portion 31 of the segment 30 and the hole portion 55 is provided at the rear portion has been illustrated. However, the present invention is not limited to this, and a configuration in which the hole portion 55 is provided at the front portion of the main body portion 31 and the arm portion 50 is provided at the rear portion may be employed. In this case, the proximal shaft portion 22, the tip shaft portion 24, and the header 25 may also be arranged in a configuration corresponding thereto.

[0113] (Embodiment 2) Next, a stylet for tracheal tube intubation assistance according to Embodiment 2 of the present disclosure will be described with reference to the drawings. As shown in FIG. 9, the stylet 120 according to Embodiment 2 includes a shaft 121 and a wire 126, and the shaft 121 includes a proximal shaft portion 122, a variable shaft portion 123, a distal shaft portion 124, and a header 125. These correspond to the shaft 21, the proximal shaft portion 22, the variable shaft portion 23, the distal shaft portion 24, the header 25, and the wire 26 in the stylet 20 of Embodiment 1, respectively, and have the same configuration in most parts. On the other hand, the stylet 120 of Embodiment 2 does not include the anti-torsion structure 34 composed of the support wall 60 and the recess 63, which is different from the stylet 20 of Embodiment 1.

[0114] FIG. 10A is a perspective view of the segment 130 of the variable shaft portion 123 included in the stylet 120 as viewed from the distal end side, and FIG. 10B is a perspective view of the same as viewed from the proximal end side. The configuration of the segment 130 will be described while comparing FIGS. 10A and 10B with FIGS. 4A and 4B. In FIGS. 10A and 10B, the same reference numerals are given to the parts having the same configuration as those in FIGS. 4A and 4B for comparison.

[0115] The segment 130 has a configuration that is mostly the same as that of the segment 30. On the other hand, the support wall 60 provided in the segment 30 is not provided at the front part of the main body portion 31 of the segment 130, and the hinge surface 41 extends to both the left and right ends at the front part of the main body portion 31. Also, the recess 63 provided in the segment 30 is not provided at the rear part of the main body portion 31 of the segment 130, and the opposing surface 44 extends to both the left and right ends at the rear part of the main body portion 31.

[0116] Segment 130 also includes an arm portion 150 corresponding to the arm portion 50 of segment 30 and a hole portion 155 corresponding to the hole portion 55 of segment 30. The arm portion 150 of segment 130 has substantially the same configuration as the arm portion 50, but has a larger width dimension in the left-right direction and is approximately one-third of the left-right dimension of the main body portion 31. The hole portion 155 into which the arm portion 150 is inserted also has a larger width dimension of the internal space than the hole portion 55 in accordance with the width dimension of the arm portion 150.

[0117] Although not shown, in the stylet 120 of the second embodiment, each segment, the header 125, and the proximal shaft portion 122 that constitute the distal shaft portion 124 also do not have a configuration corresponding to the support wall 60 and / or the recess 63, similar to the segment 130. And for such a stylet 120 as well, since the arm portion 150 and the hole portion 155 form the separation prevention structure 33 and the twist prevention structure 34, separation in the direction of the axis A1 of each part of the shaft 121 can be prevented, and displacement (twist) around the axis A1 can be prevented.

[0118] In the second embodiment, a configuration in which the support wall 60 and the recess 63 are omitted for each part of the shaft 121 is illustrated, but the support wall 60 and the recess 63 may be omitted only for a part. For example, a configuration combining the variable shaft portion 23 of the first embodiment, the proximal shaft portion 122, the distal shaft portion 124, and the header 125 of the second embodiment may be used.

[0119] (Others) Regarding the stylets according to the above-described first and second embodiments, it may further include a flexible cover that covers the shafts 21 and 121 (particularly, the variable shaft portions 23 and 123). At this time, a lubricant may be applied to a part or all of the outer surface and / or the inner surface of the flexible cover. Thereby, insertion of the stylet 20 into the tracheal tube 10 becomes easy, and the sliding resistance between the flexible cover and the stylet is also reduced, making it easier to bend the stylet 20.

[0120] Further, a visible marker for determining the position of the variable shaft portions 23 and 123 in the direction of the axis A1 may be provided on the shafts 21 and 121. Thereby, the curved portion in the stylet 20 can be easily determined. For example, the variable shaft portion 23 and the tip shaft portion 24 may have different surface colors. Further, the segments 30 located at the foremost end and the segments 30 located at the most proximal end of the variable shaft portion 23 may have a different color from the other parts of the stylet 20. Further, a line may be provided that circulates around the circumferential surface of the main body portion 31 of the segments 30 at the foremost end and the most proximal end.

[0121] Further, in the above-described first and second embodiments, the configuration in which the tip shaft portions 24 and 124 having a smaller curvature change than the variable shaft portions 23 and 123 is exemplified, but it is also possible not to provide such tip shaft portions 24 and 124. In that case, the variable shaft portions 23 and 123 may be made longer and arranged so that the headers 25 and 125 are adjacent to the tip sides thereof.

[0122] Further, here, the tip shaft portions 24 and 124 are exemplified as an example of the second shaft portion having a smaller curvature change than the first shaft portion, but the second shaft portion may be provided at another part of the stylets 20 and 120. For example, a second shaft portion may be provided between the variable shaft portion 23 and the base shaft portion 22, or the stylet may be configured to have two variable shaft portions 23 and 23, and a second shaft portion may be provided between these two variable shaft portions 23 and 23.

Industrial Applicability

[0123] The present disclosure can be suitably applied to a stylet used by being inserted into a tube, such as tracheal tube intubation assistance.

Explanation of Reference Numerals

[0124] 10 Tracheal tube 20 Stylet 21 Shaft 23 Variable shaft part 24 Tip shaft part 26 Wire 30 Segment 30A First segment 30B Second segment 31 Body part 32 Hinge structure 32a Gap 32b Fulcrum 33 Separation prevention structure 34 Twist prevention structure 40 Through hole 42 First contact part 45 Second contact part 50 Arm part 55 Hole part 62 Inner surface (first surface) 64 Outer surface (second surface)

Claims

1. A variable shaft portion that is composed of a plurality of segments arranged in the axial direction and can be bent, and a wire that is provided so as to penetrate the plurality of segments in the axial direction and applies a compressive force in the axial direction for bending the variable shaft portion. The plurality of segments include a first segment and a second segment adjacent to the first segment on the tip side in the axial direction. The variable shaft portion is provided with a hinge structure having a gap between the first segment and the second segment that allows the second segment to tilt with respect to the first segment when the variable shaft portion is bent, and a fulcrum when the second segment tilts with respect to the first segment, and an engagement structure for engaging the first segment and the second segment. The fulcrum is composed of a first contact portion of the first segment and a second contact portion of the second segment that contacts the first contact portion. When the second segment tilts with respect to the first segment by the compressive force, in the hinge structure, the first contact portion and the second contact portion roll relative to each other, and in the engagement structure, there is play in the axial direction. Stylet.

2. The gap opens toward one of the first radial directions, which is the tilting direction of the second segment with respect to the first segment, in the radial direction orthogonal to the axial direction. The fulcrum is located at the other end of the first radial direction in the gap. The stylet according to claim 1.

3. The gap opens toward one of the first radial directions, which is the tilting direction of the second segment with respect to the first segment, in the radial direction orthogonal to the axial direction. The fulcrum is provided at a position on the other side of the first radial direction with respect to the axis and at a position where the second segment does not tilt with respect to the first segment by the force in the axial direction. The stylet according to claim 1.

4. The engagement structure includes a separation prevention structure for preventing separation of the first segment and the second segment in the axial direction. The stylet according to claim 1.

5. The separation prevention structure is An arm portion that extends from the tip of the first segment in the tip direction and curves and extends in one of the radial directions that is orthogonal to the axial direction and is the tilting direction of the second segment with respect to the first segment. A hole portion formed in the second segment, in which the tip of the arm portion moves forward and backward according to the change in the posture of the second segment with respect to the first segment. The stylet according to claim 4.

6. When the first contact portion and the second contact portion are in contact with each other by the compressive force in the axial direction in the hinge structure, in the separation prevention structure, the arm portion and the hole portion have play in the axial direction. The stylet according to claim 5.

7. The engagement structure includes an anti-torsion structure that prevents the relative displacement of the first segment and the second segment around the axial direction. The stylet according to claim 1.

8. The anti-torsion structure is A first surface formed on the first segment and facing in a second radial direction that is orthogonal to the radial direction orthogonal to the axial direction and is orthogonal to the tilting direction of the second segment with respect to the first segment. A second surface formed on the second segment and provided facing the first surface in the second radial direction. The stylet according to claim 7.

9. The anti-torsion structure includes a support wall provided on the first segment and having the first surface, and a recess provided on the second segment and having the second surface. When the first contact portion and the second contact portion are in contact with each other by the compressive force in the axial direction in the hinge structure, in the anti-torsion structure, the support wall and the recess have play in the axial direction. The stylet according to claim 8.

10. The wire is provided only one in the radial direction orthogonal to the axial direction, passing through a position away from the fulcrum. The stylet according to claim 1.

11. Further comprising a flexible cover that covers the variable shaft portion. The stylet according to claim 1.

12. A visible marker is attached for discriminating the position of the variable shaft portion in the axial direction. The stylet according to claim 1.

13. A distal shaft portion provided on the distal end side in the axial direction with respect to the variable shaft portion, and further including a plurality of segments arranged in the axial direction and penetrated by the wire. When a compressive force in the axial direction is applied by the wire, the change in curvature of the distal shaft portion is smaller than the change in curvature of the variable shaft portion. The stylet according to claim 1.

14. A first shaft portion composed of a plurality of segments arranged in the axial direction and capable of being curved, A second shaft portion provided side by side with the first shaft portion in the axial direction and composed of a plurality of segments arranged in the axial direction, A wire provided so as to penetrate each of the plurality of segments of the first shaft portion and the plurality of segments of the second shaft portion, and applying a compressive force in the axial direction for bending the first shaft portion. When a compressive force in the axial direction is applied by the wire, the change in curvature of the second shaft portion is smaller than the change in curvature of the first shaft portion. Stylet.

15. A first shaft portion composed of a plurality of segments arranged in the axial direction and capable of being curved, A second shaft portion provided side by side with the first shaft portion in the axial direction and composed of a plurality of segments arranged in the axial direction, A wire provided so as to penetrate each of the plurality of segments of the first shaft portion and the plurality of segments of the second shaft portion, and applying a compressive force in the axial direction for bending the first shaft portion. Each of the plurality of segments of the first shaft portion and the plurality of segments of the second shaft portion includes a first segment and a second segment adjacent to the distal end side in the axial direction with respect to the first segment. The first shaft portion is provided with a hinge structure having a gap between the first segment and the second segment that allows the second segment to tilt with respect to the first segment when the first shaft portion is curved, and a fulcrum when the second segment tilts with respect to the first segment. The second shaft portion is not provided with the hinge structure, or is provided with a hinge structure having a gap smaller than the gap of the first shaft portion. Stylet.

16. A variable shaft portion having a plurality of segments arranged in the axial direction and configured to be curved by tilting one of two adjacent segments with respect to the other, and a wire provided so as to penetrate the plurality of segments in the axial direction and apply a compressive force in the axial direction for bending the variable shaft portion. The variable shaft portion is provided with an engagement structure for engaging two adjacent segments among the plurality of segments. The segment has an overall cross-sectional shape in a plane including the axis in an S shape, and an arm portion provided at one end in the axial direction, extending to the one end, and curving in a first radial direction which is the tilting direction among radial directions orthogonal to the axial direction, and a hole portion provided at the other end in the axial direction and extending in the first radial direction. The engagement structure includes the arm portion of one of two adjacent segments and the hole portion of the other segment. The arm portion of one segment is inserted into the hole portion of the other segment with a clearance, and the arm portion advances and retreats with respect to the hole portion according to the posture change during tilting. Stylet.

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