1. Field of the Invention
The present invention relates to a torque transmission device having a control wire. More particularly, the present invention relates to a torque transmission device in which torque can be transmitted with exactitude by removing unwanted influence of tension applied to a control wire.
2. Description Related to the Prior Art
Laparoscopic surgery is known in which a medical instrument or endoscope is entered into a body cavity percutaneously through incisions formed in abdominal skin at a size of several millimeters from tens of millimeters. A doctor or operator observes an image obtained by the endoscope by use of a display panel, and manipulates the medical instrument to conduct the laparoscopic surgery. In U.S. Pat. No. 7,637,905 (corresponding to JP-A 2006-516910), the medical instrument for use in the laparoscopic surgery has a guide tube. The guide tube only can be moved back and forth longitudinally and moved rotationally. It is difficult to handle the medical instrument for highly complicated treatment for affected tissue.
A tool arm has been developed to enable complicated movement of the medical instrument required for treatment of the affected tissue. The tool arm includes an arm and an end effector disposed at an end of the arm, having a proximal end and a distal end, the proximal end being shaped to form a curve laterally, the distal end being operated to bend inwards in the lateral direction, so as to form an angular shape or boomerang shape. See U.S. Pat. No. 7,637,905. The tool arm is operable for any of various directions, and is rotatable for complicated movement to capture the tissue, pull the tissue, apply tension to the tissue, and raise the tissue.
The tool arm is inserted through an overtube or shaft or jacket tube for use, and includes a handle section or proximal end portion, a steering unit or distal end portion, and a flexible section or shaft disposed between the handle section and the steering unit.
The steering unit is bent in one direction by pull of a pull wire extending through a lumen upon manipulating a wire puller or cuff on the handle section. When the handle section is rotated, its torque is transmitted by the flexible section to the steering unit. Thus, the handle section can be adjusted for a direction as desired for steering.
The steering unit includes a plurality of link elements and pivot mechanisms. The link elements are arranged serially. Each of the pivot mechanisms interconnects adjacent two of the link elements in a rotatable manner so as to keep the series of the link elements bendable. See U.S. Pat. No. 7,637,905. Specifically, only one end of each of the link elements is used for coupling of the pivot mechanisms. Remaining portions of the link elements beside the one end has recesses as gaps for the pivot mechanisms to bend with sufficient play. A guide lumen is formed in each of the link elements, shaped circularly as viewed in a cross section, for passage of a tool or instrument.
In U.S. Pat. No. 7,637,905, the flexible section is a series of the link elements connected with one another, and has an easy bendable form. Each of the link elements has a first end and a second end. In a manner similar to the link elements in the steering unit of the endoscope, a projection is formed on the first end. A recess is formed in the second end. The projection and the recess are arcuate, and engaged with one another to for interconnection of the link elements in a rotatable manner about a pivot axis which extends in a direction of projecting the projection or a direction of retraction of the recess. The pivot mechanisms are so arranged that the projection and the recess are disposed with angular differences of 90 degrees. The series of the link elements is bendable in the two lateral directions, but is kept rigid in the longitudinal direction and rotational direction of twist. In a manner similar to the link elements of the steering unit, the link elements are tubular circularly with the guide lumen at the center for penetration of the medical instrument. The control wire extends through the guide lumen in the link elements.
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In view of the foregoing problems, an object of the present invention is to provide a torque transmission device in which torque can be transmitted with exactitude by removing unwanted influence of tension applied to a control wire.
In order to achieve the above and other objects and advantages of this invention, a torque transmission device extending in a longitudinal axis direction is provided, and includes a first link element having a first guide lumen. A second link element is disposed at a distal end of the first link element in the longitudinal axis direction, and has a second guide lumen. A control wire is disposed through the first and second guide lumens movably in the longitudinal axis direction. A first pivot mechanism couples the first link element to the second link element in a rotatable manner about a first pivot axis being perpendicular to the longitudinal axis direction. The control wire through the first and second guide lumens extends in a coplanar manner with the first pivot axis and crosswise thereto.
The first pivot mechanism includes a first front connecting portion positioned on the first link element. A first rear connecting portion, positioned on the second link element, and engaged with the first front connecting portion in a rotatable manner.
Furthermore, a third link element is disposed at a distal end of the second link element in the longitudinal axis direction, has a third guide lumen, for receiving insertion of the control wire movably in the longitudinal axis direction. A fourth link element is disposed at a distal end of the third link element in the longitudinal axis direction, has a fourth guide lumen, for receiving insertion of the control wire movably in the longitudinal axis direction. A second pivot mechanism couples the third link element to the fourth link element in a rotatable manner about a second pivot axis being perpendicular to the longitudinal axis direction. The control wire through the third and fourth guide lumens extends in a non-coplanar manner with the second pivot axis and crosswise thereto.
The second pivot mechanism includes a second front connecting portion positioned on the third link element. A second rear connecting portion is positioned on the fourth link element, and engaged with the second front connecting portion in a rotatable manner.
Furthermore, a distal link element is positioned in a distal end of a link group including the first to fourth link elements, and provided with a distal end of the control wire retained thereon. A handle section is secured to a proximal end of the link group, for applying torque to the link group when rotated about an axis extending in the longitudinal axis direction. A wire puller is disposed on the handle section, secured to a proximal end of the control wire, for pulling the control wire when operated externally.
Furthermore, a fifth link element is disposed at a proximal end of the first link element in the longitudinal axis direction, has a guide lumen, for receiving insertion of the control wire movably in the longitudinal axis direction. An additional pivot mechanism couples the fifth link element to the first link element in a rotatable manner about a predetermined pivot axis being perpendicular to the longitudinal axis direction. The predetermined pivot axis extends in a non-coplanar manner with the first pivot axis and crosswise thereto.
The additional pivot mechanism includes an additional front connecting portion positioned on the fifth link element. An additional rear connecting portion is positioned on the first link element, and engaged with the additional front connecting portion in a rotatable manner.
There is a flexible section having the first and second link elements. A steering unit has the third and fourth link elements.
Furthermore, an intermediate link element connects the second link element with the third link element. A third pivot mechanism couples the intermediate link element to the second link element in a rotatable manner about a third pivot axis extending crosswise to the control wire in a coplanar manner. A fourth pivot mechanism couples the intermediate link element to the third link element in a rotatable manner about a fourth pivot axis extending in a non-coplanar manner with the control wire and crosswise thereto.
The first pivot mechanism further includes a contact surface, formed on the first or second link element in a retracted manner, for allowing the first and second link elements to rotate relative to one another, the contact surface having a predetermined width in a first direction perpendicular to the first pivot axis, the predetermined width being equal to or more than a width of the first and second guide lumens in the first direction.
Furthermore, a coating is applied to the contact surface, for increasing resistance of friction.
Furthermore, a fine surface pattern of projections or recesses, formed on the contact surface, for increasing resistance of friction.
The contact surface includes an arcuate surface. A flat surface is formed by partially chamfering the arcuate surface.
Furthermore, a coating is applied to the contact surface, for increasing slipping property.
The first pivot mechanism includes a connecting projection being arcuate when viewed in a section. A connecting recess is arcuate when viewed in a section, for receiving the connecting projection. An inclined surface is formed with each of two walls of the connecting recess, for guiding the connecting projection toward the connecting recess.
The first pivot mechanism includes a connecting projection being arcuate when viewed in a section. A connecting recess is arcuate when viewed in a section, for receiving the connecting projection. A snap-fit structure allows push of the connecting projection into the connecting recess by resilient deformation for assembly, and keeps the connecting projection rotatable in the connecting recess after the push.
Also, the torque transmission device is used with an endoscope and entered in a body cavity together with an elongated tube of the endoscope.
In one preferred embodiment, the torque transmission device is incorporated in a high frequency snare instrument for medical use.
Consequently, torque can be transmitted with exactitude by removing unwanted influence of tension applied to a control wire, because the control wire through the guide lumens in the link elements is set coplanar with the first pivot axis of the link elements.
The above objects and advantages of the present invention will become more apparent from the following detailed description when read in connection with the accompanying drawings, in which:
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A plurality of link elements or sleeves 15 for the steering unit (third and fourth link elements) are connected with one another to constitute the steering unit 13. A link elements or sleeves 16 for the flexible section (first, second and fifth link elements) are connected with one another to constitute the flexible section 14. Only one control wire is disposed to extend through the guide tube structure 11. Examples of materials for forming the link elements 15 and 16 may be resin, metal and other suitable substances having sufficient rigidity. Among those, metal is specifically preferable if a decrease in the diameter of the guide tube structure 11 is desired for some purposes.
A grip 17 and a rotatable wheel 18 are disposed on the handle section 12. The wheel 18 is rotatable about an axis of the guide tube structure 11 extending in a longitudinal axis direction. When the wheel 18 is rotated in one direction, one control wire is pulled to bend the steering unit 13 in one direction for steering. When the wheel 18 is rotated back to its original position, the steering unit 13 is bent back and returns to its straight form. Also, when the grip 17 is manually rotated with fingers of a user, torque of the grip 17 is transmitted by the flexible section 14 to the steering unit 13. Thus, the steering unit 13 can be oriented in a desired direction by adjustment.
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The connecting recess 22 of the distal link element 20 is shaped semi-circularly as viewed in a section. A pivot axis of the connecting recess 22 is perpendicular to the longitudinal axis direction of the link elements. A position of the connecting recess 22 is eccentric with respect to the longitudinal axis direction, and at one point of a tubular end surface of the distal link element 20. There is a link group 24 or multi link component for the steering unit. A connecting projection 25 as a front connecting portion is formed with a distal one of the link elements 15 in the link group 24. The connecting recess 22 is engaged with the connecting projection 25. An inclined surface 26 is formed by chamfering a portion of the end surface other than the connecting recess 22, and defines a gap for bending in cooperation with an adjacent one of the link elements 15.
Each one of the link elements 15 is a sleeve, has a first end where the connecting projection 25 and the inclined surface 26 are formed, and a second end where the connecting recess 22 and the inclined surface 26 are formed. See
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The link element 15 is shaped circularly as viewed in a section. In
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The link group 31 is a series of the link elements 16. Each of the link elements 16 has connecting recesses 36 as a front connecting portion, inclined surfaces 38, and a guide lumen 37 or wire lumen. The connecting recesses 36 are located at a first end of the link elements 16. The inclined surfaces 38 and the connecting projections 32 are located at a second end of the link elements 16. The guide lumen 37 is formed to extend in the longitudinal axis direction. See
The connecting recesses 36 are formed arcuately as viewed in a section, and symmetrically with respect to the longitudinal axis direction, and so disposed that the guide lumen 37 is positioned between those. The connecting recesses 36 at a first end of the link elements 16 and the connecting projections 32 at a second end of the link elements 16 are so constructed that the pivot axis 41 of a distal side is kept non-coplanar with the pivot axis 41 of a proximal side, namely in a condition of non-intersecting skew lines being perpendicularly crossed when viewed in a projected manner. In short, the pivot axis 41 of the connecting recesses 36 is directed to extend with an angular difference of 90 degrees from the pivot axis 41 of the connecting projections 32. As the connecting projections 32 are engaged with the connecting recesses 36 with differences in the angle of the pivot axis 41 at 90 degrees, a bendable property of the link elements 16 is given in the four directions. The link elements 16 can have rigidity with respect to its longitudinal direction and rotational direction of twist. Note that in the second pivot mechanism 40, the connecting recesses 36 are oriented in the distal direction and the connecting projections 32 are oriented in the proximal direction. However, it is possible to determine the directions of the connecting recesses 36 and the connecting projections 32 in a manner opposite to those of the embodiment. The connecting projections 32 or the connecting recesses 36 constitute a front connecting portion as a feature of the invention.
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Note that it is unnecessary for the guide lumen 37 to maintain the control wire 23 on the longitudinal axis 42 with high exactitude. See
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Female threads 47 are formed on an inner surface of the wheel 18 as screw hole. An end tab portion 45 has male threads 46, which are engaged helically with the female threads 47. A proximal wire end 23b of the control wire 23 is fixedly secured to the end tab portion 45.
A wire puller including the wheel 18 also has a mechanism for preventing twist of the control wire 23. The mechanism includes a key groove 55 and a key projection 56. The key groove 55 is formed in an inner surface of the grip 17 and extends longitudinally. The key projection 56 is formed on the control wire 23. The key projection 56 is engaged with the key groove 55 to prevent the control wire 23 from twisting. The end tab portion 45 can be kept fixed rotationally.
When the wheel 18 is rotated in a first direction, the end tab portion 45 is moved in a proximal direction on the axis. The control wire 23 is pulled to bend the steering unit 13 in one direction for steering. When the wheel 18 is rotated in a second direction, the end tab portion 45 is moved in a distal direction on the axis. The control wire 23 is loosened to release the steering unit 13 from being bent for steering.
A pair of key projections 53 are formed on sides of the proximal link element 44 at the proximal end, so that the guide lumen 37 is located between those. A key groove 54 is formed inside an end portion of the grip 17, and is engaged with each of the key projections 53. When the grip 17 is rotated, its torque is transmitted by the flexible section 14 to the steering unit 13, of which a direction can be adjusted as desired by an operator.
Note that the control wire is single, but can operate for steering in one intended direction. At first, the handle section is rotated about the longitudinal axis to determine an orientation of the steering unit. Then the wheel of the wire puller is rotated so that the bending of the steering unit in the determined orientation is possible.
Various known mechanisms can be used for the wire puller. For example, a mechanism including a pull lever for pulling the control wire 23 can be used. The pull lever has a first end where the control wire 23 is secured and a second end disposed to protrude externally. A rotational axis of the pull lever is disposed between the first and second ends. When the pull lever is swung in a distal direction, the control wire 23 is pulled. A lock mechanism for locking the pull lever in the swing position is disposed. When the lock mechanism is released, the pull lever comes back to an erect position, to loosen the control wire 23.
The torque transmission device 10 is usable for pressing an organ in a body with considerable softness to ensure a large field of view for surgery as described with the prior art, and also for guiding an overtube to reach an object of interest.
For example, the Natural Orifice Transluminal Endoscopic Surgery (NOTES) is known, in which a gastric submucosal tumor or pancreas is treated by entry into a abdominal cavity through a lumen of a large intestine, rectum, vagina or the like. This method has been recently highlighted owing to small physical stress to a body of a patient in comparison with abdominal surgery or laparoscopic surgery. For example, the endoscope enters the abdominal cavity through the vagina. The sacral spine is located on a straight line passing through the affected tissue and a point of entry. It is necessary for the overtube to reach the stomach or pancreas by steering the overtube in an S shape away from the sacral spine.
Examples of the overtube are disclosed in U.S. Pat. No. 5,174,276 (corresponding to JP-A 4-501676) and U.S. Pat. No. 5,337,733 (corresponding to JP-A 5-503434), in which its condition is changeable between flexible and rigid states even during the use. The overtube, when in the flexible state, is freely flexible, and when in the rigid state, is prevented from flexing. An example of endoscope is an electronic endoscope, of which an elongated tube or insertion tube is constituted by a head assembly, a steering unit and a flexible section arranged in a proximal direction. The steering unit is bendable in a direction as desired by operating the handle section. The flexible section extends between the steering unit and the handle section. An image pickup device is incorporated in the head assembly. An image is produced by the endoscope, displayed on a monitor display panel, and observed by a doctor or operator who manipulates the overtube for surgery.
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In the torque transmission device 10, the flexible section 14 does not flex even upon bending the steering unit 13. An original form of the flexible section 14 is maintained. Thus, the torque transmission device 10 is effectively used for a purpose of bending the steering unit 13 for bypassing the sacral spine 64 and maintaining remaining portions without bending, specifically for the Natural Orifice Transluminal Endoscopic Surgery (NOTES).
It is possible to use various structures known in the art for the purpose of achieving the purpose of the invention.
There are various situations of no occurrence of influence to the flexed form of the flexible section 14 even in occurrence of tension with the control wire 23. In a first one of the situations, the tension with the control wire 23 engages the link elements 16 with one another to maintain the present shape of the flexible section 14. In a second one of the situations, the link elements 16 are movable from one another even in occurrence of the tension with the control wire 23, so that the flexible section 14 is still flexible.
To engage the link elements 16 with one another for maintaining the shape in an unchanged manner, a coefficient of friction can be effectively increased between the connecting projections 25 and 32 and the connecting recesses 22 and 36 in the first and second pivot mechanisms 27 and 40. For example, a coating with the high coefficient of friction can be preferably applied to contact surfaces of the connecting projections 32 and the connecting recesses 36 in the second pivot mechanism 40. Also, fine projections 70 of a contact surface as a fine surface pattern can be formed on the connecting projections 32, the connecting recesses 36 or on both of those in place of the coating. See
Furthermore, it is preferable to apply a coating of diamond-like carbon (DLC) to surfaces of the connecting projections 32 and the connecting recesses 36 specifically for the purpose of maintaining slide between the link elements 16 and flexibility in the flexible section 14 even upon occurrence of tension in the control wire 23, because the diamond-like carbon (DLC) has slipping property and resistance to abrasion. The coating is effective in lowering a friction coefficient of the surfaces and increasing the slipping property.
The link elements 16 of the above embodiment have the guide lumen 37 extending in the longitudinal axis direction. Furthermore, the link elements 16 may be formed in a double sleeve structure. For this purpose, a link element includes an inner barrel and an outer barrel. In
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In the above embodiments, the link group 24 for the steering unit is located at a distal end of the guide tube structure 11. The link group 31 for the flexible section is located at a proximal end of the guide tube structure 11. However, combinations of locations of the link groups 24 and 31 can be modified suitably for various purposes. It is possible to dispose a plurality of the link groups 24 at a predetermined distance in the guide tube structure 11. Also, the link group 31 may constitute a distal end portion, intermediate portion or proximal end portion of the guide tube structure 11.
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If the torque transmission device 10 or 90 of the above embodiments is flexed, acute edges may be formed at end portions of the link elements 15 and 16. It is likely that tissue in a body cavity is injured by the acute edges. Thus, a covering tube can be additionally used to cover the guide tube structure 11 of the torque transmission device 10 for the purpose of higher safety. It is possible only to cover the steering unit 13 with such a covering tube.
The torque transmission device of any of the above embodiments can be used with a medical instrument, for example, with a high frequency snare instrument 110. See
The snare loop 114, when advanced to protrude, becomes developed in a loop form with its resiliency, and when moved back into the flexible sheath 113, becomes squeezed by resilient deformation. An opening is formed partially in the slider 111. A plug 115 is disposed to appear in the opening for powering with high frequency current. The high frequency snare instrument 110 is entered in a body cavity through an instrument channel of an endoscope. The snare loop is moved to catch a root portion of protrusion of affected tissue, so as to excise polyp or the like by burning the polyp or firmly closing to cut the root portion.
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In the above embodiments, the torque transmission device 10 is an instrument for medical use. However, the torque transmission device 10 may be an instrument for any of the industrial fields in relation to a steerable device, steerable catheter, link assembly, robot arm, and the like.
Although the present invention has been fully described by way of the preferred embodiments thereof with reference to the accompanying drawings, various changes and modifications will be apparent to those having skill in this field. Therefore, unless otherwise these changes and modifications depart from the scope of the present invention, they should be construed as included therein.
Number | Date | Country | Kind |
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2010-039440 | Feb 2010 | JP | national |