Patent Publication Number: US-2021161367-A1

Title: Endoscope

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of PCT/JP2018/031049 filed on Aug. 22, 2018, the entire contents of which are incorporated herein by this reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an endoscope including an insertion section provided with a portion which bends passively. 
     2. Description of the Related Art 
     An endoscope for medical use includes an elongated insertion section which is insertable into a subject, and can perform observation of an inside of the subject and treatment using a treatment instrument or the like. As one of endoscopes for medical use, for example, there has been known an endoscope for renal pelvis and urinary organs (nephroscope) disclosed in Japanese Patent Application Laid-Open Publication No. 2016-187554. 
     As disclosed in Japanese Patent Application Laid-Open Publication No. 2016-187554, an insertion section of an endoscope for renal pelvis and urinary organs is inserted into a ureter of a subject through an access sheath. The access sheath is a tubular member. By holding the access sheath in the ureter in an inserted state, the repeated insertion and removal of the insertion section of the endoscope into and out from the ureter can be performed easily. 
     SUMMARY OF THE INVENTION 
     An endoscope according to an aspect of the present invention includes: an insertion section inserted into a subject; an operation section disposed on a proximal end side of the insertion section; a bending portion forming a portion of the insertion section, at least a portion of the bending portion being extendable and contractible in a longitudinal axis direction of the insertion section; a longitudinal member configured to maintain a constant distance from the operation section to a distal end portion of the insertion section along the longitudinal axis of the insertion section; and a flexible tube portion forming a portion of the insertion section, disposed on a proximal end side with respect to the bending portion, provided in a movable manner with respect to the operation section and the longitudinal member in the longitudinal axis direction, and configured to make the bending portion extend and contract with movement of the flexible tube portion with respect to the operation section in the longitudinal axis direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view showing a schematic configuration of an endoscope according to a first embodiment; 
         FIG. 2  is a view showing a configuration of an insertion section according to the first embodiment; 
         FIG. 3  is a view showing the insertion section according to the first embodiment in a state where a second bending portion is compressed; 
         FIG. 4  is a view showing a configuration of an insertion section according to a modification of the first embodiment; 
         FIG. 5  is a view showing the insertion section according to the modification of the first embodiment in a state where a second bending portion is compressed; 
         FIG. 6  is a view showing a configuration of an insertion section according to a second embodiment; 
         FIG. 7  is a view showing a distal end portion of an insertion section according to a third embodiment; and 
         FIG. 8  is a partial cross-sectional view of a distal end portion of an insertion section according to a fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, preferred embodiments of the present invention are described with reference to drawings. In the respective drawings used in the description made hereinafter, for the sake of setting sizes of respective components legible in the drawings, the scales of the respective components are made different from each other. The present invention is not limited to the number and the amounts of components, the shapes of the components, the ratios between the sizes of the components, and the relative positional relationships among the respective components described in the drawings. 
     First Embodiment 
     An endoscope  1  shown in  FIG. 1  includes an elongated insertion section  2  which is insertable into a subject such as a human body, and the insertion section  2  has a configuration for observing the inside of the subject. The subject into which the insertion section  2  of the endoscope  1  is inserted is not limited to a human body, but may be other living bodies or an artificial object such as a machine or a building. 
     In the embodiment, as an example, the subject is a human body. In the embodiment, as an example, the endoscope  1  is an endoscope for renal pelvis and urinary organs (nephroscope). In the embodiment, as an example, the endoscope  1  is configured as a so-called videoscope. 
     The endoscope  1  includes: the insertion section  2  which is long along a predetermined axis; an operation section  3  which is positioned on a proximal end which is one end of the insertion section  2 ; and a universal cord  4  which extends from the operation section  3 . 
     The operation section  3  is a part which a user grasps. In the operation section  3 , a treatment instrument insertion opening  3   a  and a bending operation portion  20  are disposed. A connector  4   a  which is connected to an external apparatus not shown is provided to the universal cord  4 . 
     Hereinafter, with respect to the insertion section  2 , the predetermined axis which is disposed parallel to a longitudinal direction is referred to as a longitudinal axis L. As described previously, the proximal end of the insertion section  2  is connected to the operation section  3 . The other end of the insertion section  2  on a side opposite to the proximal end is referred to as a distal end. 
     As shown in  FIG. 2 , the insertion section  2  includes a distal end portion  10 , a first bending portion  11 , a second bending portion  12 , and a flexible tube portion  13 . The distal end portion  10 , the first bending portion  11 , the second bending portion  12  and the flexible tube portion  13  are connected to each other in this order from the distal end toward the proximal end along the longitudinal axis L of the insertion section  2 . 
     The distal end portion  10  is disposed on the distal end of the insertion section  2 . An image pickup unit, an illumination light irradiation member and a channel opening  10   a  are disposed in the distal end portion  10 . 
     The image pickup unit is an apparatus for picking up an optical image. The image pickup unit includes an objective lens and an image pickup device. A portion of the image pickup unit may be disposed in the operation section  3 . For example, the image pickup unit may be configured to include: an objective lens disposed in the distal end portion  10 ; an image pickup device disposed in the operation section  3 ; and an image guide fiber which is inserted through the insertion section  2 . 
     The image pickup unit is electrically connected to the connector  4   a  via an electric cable disposed in the endoscope  1 . When the connector  4   a  is connected to an external apparatus, the image pickup unit is electrically connected to the external apparatus. The external apparatus includes a processor which displays an optical image picked up by the image pickup unit on a display apparatus not shown. 
     The illumination light irradiation member irradiates light which illuminates an object by the image pickup unit. A light source for supplying light irradiated from the illumination light irradiation member may be disposed in the endoscope  1 , or may be disposed in the external apparatus. The image pickup unit and the illumination light irradiation member of the endoscope  1  are known techniques and hence, the detailed description of the image pickup unit and the illumination light irradiation member is omitted. 
     The channel opening  10   a  communicates with a distal end of a longitudinal member  5  which is formed of a tube. A proximal end of the longitudinal member  5  communicates with the treatment instrument insertion opening  3   a  formed in the operation section  3 . Accordingly, the longitudinal member  5  is inserted through the insertion section  2  and the operation section  3 . A distal end of the longitudinal member  5  is fixed to the distal end portion  10  of the insertion section  2 . A portion of the longitudinal member  5  positioned in the operation section  3  is fixed to the operation section  3 . The longitudinal member  5  has flexibility so as to be bendable following bending of the insertion section  2 . Although described in detail later, the longitudinal member  5  has rigidity in a predetermined compression direction. In the embodiment, as an example, the longitudinal member  5  is formed of a tube. However, the longitudinal member  5  may be formed of a columnar member which is not hollow. The endoscope  1  may include a plurality of longitudinal members  5 . 
     The first bending portion  11  is disposed on a proximal end side of the distal end portion  10 . The first bending portion  11  actively bends in response to an operation of the bending operation portion  20  performed by a user. A plurality of wires  14  are inserted through the insertion section  2 . Distal ends of the individual wires  14  are fixed to the first bending portion  11  in a vicinity of the distal end of the first bending portion  11 . The first bending portion  11  has flexibility, and a bent shape of the first bending portion  11  changes corresponding to a towing amount in a direction toward proximal ends of the plurality of wires  14 . 
     The proximal ends of the plurality of wires  14  are connected to a towing mechanism portion  22  disposed in the operation section  3 . The towing mechanism portion  22  performs towing and slackening of the plurality of wires  14  in response to an operation of the bending operation portion  20  by a user. The technique for actively bending the insertion section of the endoscope is known and hence, the detailed description of the technique is omitted. 
     In the embodiment, as an example, the bending operation portion  20  is a lever which relatively moves in two directions with respect to the operation section  3 . In the embodiment, as an example, the towing mechanism portion  22  tows and slackens two wires  14  in response to movement of the lever. In the embodiment, as an example, the first bending portion  11  actively bends in two directions in response to towing and slackening of the two wires  14 . The first bending portion  11  may be configured to bend in four directions. 
     The second bending portion  12  is disposed on a proximal end side of the first bending portion  11 . The second bending portion  12  has flexibility, and passively bends in response to an external force. The second bending portion  12  extends and contracts in a direction along the longitudinal axis L. The configuration which allows the second bending portion  12  to extend and contract in the direction along the longitudinal axis L is not particularly limited. As shown in  FIG. 2 , in the embodiment, as an example, an outer peripheral member of the second bending portion  12  is configured by a bellows. In such a configuration, the outer peripheral member is a structural member of the second bending portion  12 , and is a member in which one or a plurality of conduits are formed in a penetrating manner in a direction along the longitudinal axis L. The wires  14 , the longitudinal member  5 , electric cables and the like are inserted through one or a plurality of conduits which the outer peripheral member includes. An outer peripheral member of the first bending portion  11  may also be configured by a bellows in the same manner as the second bending portion  12 . 
     The second bending portion  12  exhibits a lower rigidity than the longitudinal member  5  and the wires  14  against a force in a direction along the longitudinal axis L. In other words, the longitudinal member  5  has a higher rigidity in a compression direction than the second bending portion  12 . The wires  14  have a higher rigidity in an extending direction than the second bending portion  12 . 
     The flexible tube portion  13  is disposed on a proximal end side of the second bending portion  12 . The flexible tube portion  13  has flexibility, and passively bends in response to an external force. The flexible tube portion  13  has a higher rigidity than the second bending portion  12  against a force in a direction along the longitudinal axis L. In other words, when a compression force in a direction along the longitudinal axis L is applied to the insertion section  2 , a deformation amount of the flexible tube portion  13  is smaller than a deformation amount of the second bending portion  12 . 
     The flexible tube portion  13  is provided in a movable manner in a direction along the longitudinal axis L with respect to the operation section  3 , the wires  14  and the longitudinal member  5 . A force which moves the flexible tube portion  13  with respect to the operation section  3  may be generated by a user, or may be generated by an electrically operated actuator. 
     In the embodiment, as an example, the flexible tube portion  13  moves in the direction along the longitudinal axis L with respect to the operation section  3  by a force which a user generates. More specifically, when the user grasps the operation section  3  with one hand, and applies a force in the direction along the longitudinal axis L to the flexible tube portion  13  with the other hand, the flexible tube portion  13  moves in the direction along the longitudinal axis L with respect to the operation section  3 . At this stage of the operation, the wires  14  are connected to the towing mechanism portion  22  disposed in the operation section  3  and hence, the flexible tube portion  13  moves in the direction along the longitudinal axis L with respect to the wires  14 . In the same manner, the longitudinal member  5  is fixed to the operation section  3  and hence, the flexible tube portion  13  moves in the direction along the longitudinal axis L with respect to the longitudinal member  5 . The flexible tube portion  13  moves with respect to the operation section  3  independently from internal components such as the electric cables inserted through the insertion section  2 . 
     Even when the flexible tube portion  13  moves in the direction along the longitudinal axis L with respect to the operation section  3 , a distance from the operation section  3  to the distal end of the insertion section  2  along the longitudinal axis L of the insertion section  2  does not change. More specifically, in the embodiment, when the flexible tube portion  13  moves toward the distal end with respect to the operation section  3 , a force in the extending direction is applied to the wires  14 . However, the wires  14  have rigidity which maintains a distance from the operation section  3  to the first bending portion  11  along the longitudinal axis L of the insertion section  2 . Accordingly, when the flexible tube portion  13  moves toward the distal end with respect to the operation section  3 , as shown in  FIG. 3 , the second bending portion  12  is compressed in the direction along the longitudinal axis L. 
     On the other hand, when the flexible tube portion  13  moves toward the proximal end with respect to the operation section  3  from a state shown in  FIG. 3 , a force in a compression direction is applied to the longitudinal member  5 . However, the longitudinal member  5  has rigidity which maintains the length without buckling deformation. In other words, when the flexible tube portion  13  moves toward the proximal end side, the longitudinal member  5  maintains a distance from the operation section  3  to the first bending portion  11  along the longitudinal axis of the insertion section  2 . Accordingly, when the flexible tube portion  13  moves toward the proximal end with respect to the operation section  3 , as shown in  FIG. 2 , the second bending portion  12  extends in the direction along the longitudinal axis L. 
     In the embodiment, bending rigidity of the second bending portion  12  in a state where a length of the second bending portion  12  is longest is lower than bending rigidity of the flexible tube portion  13 . In the embodiment, bending rigidity indicates difficulty in deformation when the second bending portion  12  extending along the longitudinal axis L is deformed by bending. The larger the bending rigidity, the smaller a deformation amount in the bending direction becomes. 
     In the endoscope  1  according to the embodiment, when a user moves the flexible tube portion  13  in the direction along the longitudinal axis L, the length of the second bending portion  12  changes. In a first state ( FIG. 2 ) where the flexible tube portion  13  is positioned on a most proximal end side, bending rigidity of the second bending portion  12  is maintained at a value lower than bending rigidity of the flexible tube portion  13 . On the other hand, in a second state ( FIG. 3 ) where the flexible tube portion  13  is positioned on a most distal end side, the second bending portion  12  is compressed in the direction along the longitudinal axis L and hence, bending rigidity of the second bending portion  12  becomes higher than the bending rigidity in the first state. 
     In the endoscope  1  according to the embodiment having the configuration described above, when a distal end of the insertion section  2  is inserted into an inlet of an access sheath, the second bending portion  12  is compressed so that bending rigidity of the second bending portion  12  is increased whereby the insertion section  2  can be easily inserted into the access sheath. 
     In the endoscope  1  according to the embodiment, a distal end of the insertion section  2  is inserted into the access sheath and, thereafter, the second bending portion  12  is extended so that bending rigidity of the second bending portion  12  is lowered. Accordingly, the insertion section  2  in a subject can be easily handled. 
     The endoscope  1  according to the embodiment described above is configured such that a user directly grasps the flexible tube portion  13  and moves the flexible tube portion  13 . However, the endoscope  1  may have a rotatable dial on the operation section  3 , and may have a mechanism which converts a rotational force of the dial into a force which moves the flexible tube portion  13 . 
     In the embodiment described above, the second bending portion  12  is configured by a bellows. However, it is sufficient that the second bending portion  12  is extendable and contractible in the direction along the longitudinal axis L.  FIG. 4  and  FIG. 5  show a modification of the second bending portion  12 . 
     The second bending portion  12  of the modification shown in  FIG. 4  and  FIG. 5  is formed of a tubular member which is flexible and elastically deformable. In the modification, in a first state ( FIG. 4 ) where a flexible tube portion  13  is positioned on a most proximal end side, and a length of the second bending portion  12  is longest, an outer surface of the second bending portion  12  is smooth. On the other hand, in a second state ( FIG. 5 ) where the flexible tube portion  13  is positioned on a most distal end side, and the length of the second bending portion  12  is shortest, wrinkles are formed on the outer surface of the second bending portion  12 . 
     Bending rigidity of the second bending portion  12  can also be enhanced in the modification, in the same manner as the embodiment described previously, by compressing the second bending portion  12  in a direction along a longitudinal axis L. Accordingly, also in the endoscope  1  according to the modification, the insertion section  2  can be easily inserted into an access sheath. 
     Second Embodiment 
     Hereinafter, a second embodiment of the present invention is described. Hereinafter, only components which make the second embodiment differ from the first embodiment are described, and components which are identical with the corresponding components in the first embodiment are given with the same symbols, and the description of such components is omitted when desired. 
       FIG. 6  is a view showing a configuration of an insertion section  2  of an endoscope  1  according to the second embodiment. A first bending portion  11  of the insertion section  2  of the embodiment extends and contracts in a direction along a longitudinal axis L. The configuration which allows the first bending portion  11  to extend and contract in the direction along the longitudinal axis L is not particularly limited. As shown in  FIG. 6 , in the embodiment, as an example, an outer peripheral member of the first bending portion  11  is configured by a bellows in the same manner as a second bending portion  12 . 
     In the endoscope  1  according to the embodiment, when a user moves a flexible tube portion  13  in the direction along the longitudinal axis L, a length of the first bending portion  11  and a length of the second bending portion  12  change. In a state where the flexible tube portion  13  is positioned on a most distal end side, the first bending portion  11  and the second bending portion  12  are compressed in the direction along the longitudinal axis L and hence, bending rigidity of the first bending portion and bending rigidity of the second bending portion  12  are increased. 
     When an outer peripheral member of the first bending portion  11  is configured by a bellows as in the case of the embodiment, it is difficult to provide a configuration which restricts a direction of bending deformation to the first bending portion  11 . The configuration which restricts the direction of the bending deformation may be configured by a plurality of bending pieces which are disposed on a bending portion of a conventional endoscope, for example. Accordingly, in a state where the flexible tube portion  13  is positioned on a most proximal end side, the first bending portion  11  of the embodiment is liable to generate bending deformation in a direction different from a direction that the first bending portion  11  is bent due to towing of wires  14  caused by gravity or the like. Accordingly, in the endoscope  1  according to the embodiment, when a distal end of the insertion section  2  is inserted into an inlet of an access sheath, the first bending portion  11  is compressed so that bending rigidity of the first bending portion  11  is increased whereby a deformation amount of the first bending portion  11  can be suppressed. 
     As described above, in the endoscope  1  according to the embodiment, when the distal end of the insertion section  2  is inserted into the inlet of the access sheath, bending rigidity of the first bending portion  11  and bending rigidity of the second bending portion  12  are increased and hence, the insertion section  2  can be easily inserted into the access sheath. 
     Third Embodiment 
     Hereinafter, a third embodiment of the present invention is described. Hereinafter, only components which make the third embodiment differ from the first embodiment are described, and components which are identical with the corresponding components in the first embodiment are given with the same symbols, and the description of such components is omitted when desired. 
       FIG. 7  is a perspective view showing a distal end portion  10  of an insertion section  2  of an endoscope  1  according to the third embodiment. As shown in  FIG. 7 , an image pickup unit  31 , an illumination light irradiation member  32  and a channel opening  33  are disposed on the distal end portion  10 . 
     In the embodiment, an image pickup unit  31  and an illumination light irradiation member  32  are mounted on a distal end side with respect to the channel opening  33 . In other words, the image pickup unit  31  and the illumination light irradiation member  32  are disposed on a protruding portion  10   a  protruding toward a distal end side with respect to the channel opening  33 . 
     A tube is not disposed in the protruding portion  10   a  and hence, the protruding portion  10   a  has a smaller diameter than a proximal end of the distal end portion  10 . In other words, a cross-sectional area of the protruding portion  10   a  on a plane orthogonal to a longitudinal axis L is smaller than a cross-sectional area of the proximal end of the distal end portion  10 . The protruding portion  10   a  has a portion which is elastically deformable and hence, the protruding portion  10   a  is bendable. 
     In the endoscope  1  according to the embodiment, in a state where the insertion section  2  is inserted into a ureter, the elongated protruding portion  10   a  bends along a shape of the ureter. Accordingly, in the endoscope  1  according to the embodiment, a user can make the insertion section  2  easily advance in the ureter by pushing in a distal end direction. 
     Fourth Embodiment 
     Hereinafter, a fourth embodiment of the present invention is described. Hereinafter, only components which make the fourth embodiment differ from the third embodiment are described, and components which are identical with the corresponding components in the third embodiment are given with the same symbols, and the description of such components is omitted when desired. 
       FIG. 8  is a partial cross-sectional view of a distal end portion  10  of an insertion section  2  of an endoscope  1  according to the fourth embodiment. As has been described in the third embodiment, a protruding portion  10   a  protruding toward a distal end side with respect to a channel opening  33  is disposed on the distal end portion  10 . 
     A bendable third bending portion  10   b  is disposed on a portion of the protruding portion  10   a . An outer surface of the third bending portion  10   b  is formed of a resin or the like which is elastically deformable. An image pickup unit  31  and an illumination light irradiation member  32  (not shown) are mounted on the protruding portion  10   a.    
     In the embodiment, a rigidity changing mechanism  34  is disposed inside the third bending portion  10   b.    
     The rigidity changing mechanism  34  includes a coil  34   a  and a bio metal fiber  34   b . The coil  34   a  is wound around the bio metal fiber  34   b  about an axis parallel to a longitudinal axis L. The bio metal fiber  34   b  is a linear member made of a material which contracts when electricity is supplied to the material. 
     The bio metal fiber  34   b  is inserted through the coil  34   a . Both ends of the coil  34   a  are fixed to the bio metal fiber  34   b . In other words, when the bio metal fiber  34   b  contracts, the coil  34   a  is compressed. 
     The bio metal fiber  34   b  is electrically connected to an electricity supply cable not shown. The supply of electricity to the bio metal fiber  34   b  is switched by a switch mounted on an operation section  3 . 
     The rigidity changing mechanism  34  having the configuration described above can make the bending rigidity of the third bending portion  10   b  when electricity is supplied to the bio metal fiber  34   b  higher than the bending rigidity of the third bending portion  10   b  when electricity is not supplied to the bio metal fiber  34   b.    
     Accordingly, in the endoscope  1  according to the embodiment, by switching the supply of electricity to the bio metal fiber  34   b  between a supply state and a non-supply state, bending rigidity of the third bending portion  10   b  of the protruding portion  10   a  can be changed. 
     In the endoscope  1  according to the embodiment, by bringing the protruding portion  10   a  into a state where rigidity of the protruding portion  10   a  is increased, the insertion section  2  can be easily inserted into an access sheath. 
     The present invention is not limited to the above-mentioned embodiments, and modifications can be made without departing from the gist or the concept of the present invention readable from claims and the entire specification, and endoscopes which include such modifications also fall within the technical scope of the present invention.