The invention relates to a surgical device for minimally invasive surgery, comprising a shaft extending along a longitudinal axis to a distal end thereof, and a surgical module mounted to the distal end of the shaft and provided with a movable surgical element, wherein the shaft includes a tube that is rotatable relative to the shaft and a further tube, wherein the shaft further includes at least one slider connected to the surgical module and operatively driven by the rotatable tube via a rotary to linear linkage such that a rotation of the rotatable tube around the longitudinal axis induces a movement of the slider along the longitudinal axis thereby inducing a movement of the movable surgical element.
Typically, minimally invasive operations are performed through small portals for accessing deeper located tissue. During use of a known surgical device for minimally invasive surgery, the surgical module provided on the distal end of the shaft is brought into the body, via the portals, to manipulate said tissue. By interaction with the shaft, at a proximal end thereof, the at least one slider can be driven to induce a movement of the movable surgical element.
In the surgical device disclosed in International patent publication WO 2014/148898, one of the inventors being the inventor of the present invention, the rotary to linear linkage includes a three layer coaxial structure, viz. an inner tube and an outer tube as well as a pair of sliders provided with axially extending pins that traverse spiral shaped slits that are provided in both tubes. During operation, the inner and outer tube rotate in mutual reverse order thereby inducing the sliders to move in a direction parallel to the longitudinal axis of the tubes.
In principle, such multiple coaxial structures can be applied for moving the surgical elements of the surgical module, in order to meet minimally invasive surgery purposes. However, due to the small size of the portals, the total number of coaxial structures in the shaft for operating the surgical module is to be limited.
It is an object of the invention to provide a surgical device for minimally invasive surgery according to the preamble, wherein the number of coaxial structure in the shaft is reduced without loosing functionality of the surgical module. Thereto, according to the invention, the further tube, coaxial with the rotatable tube, is rotationally stationary relative to the shaft, wherein the at least one slider is rotationally locked relative to the stationary tube.
By rotationally locking the at least one slider to a stationary tube, the slider might be still movable in the longitudinal direction, when driven by the rotatable tube, while, on the other hand, the slider does not need to be located at the same longitudinal level of the both tubes, thereby enabling a two layer radial implementation of the rotation to linear linkage.
The invention is at least partly based on the insight that a rotation to linear linkage can in principle be realized by a two layer radial structure provided that the linear moving element is locked against rotational movement.
Advantageously, the stationary tube is provided, at its distal end, with a cut away extending along the longitudinal axis and receiving a proximal portion of the slider. Then, the stationary tube and the slider can be integrated in a single radial layer effectively reducing the number of radial layers of the shaft.
The invention also relates to a method of assembling a surgical device for minimally invasive surgery.
Further, the invention relates to a method for de-assembling a surgical device for minimally invasive surgery.
Other advantageous embodiments according to the invention are described in the following claims.
By way of example only, embodiments of the present invention will now be described with reference to the accompanying figures in which
The figures merely illustrate a preferred embodiment according to the invention. In the figures, the same reference numbers refer to equal or corresponding parts.
The surgical module 3 includes a basic module 3A and two movable surgical elements, viz. a first and a second grasper beak 3B, 3C. The grasper beaks 3B, 3C are movable in a first swiveling direction BD1 and in a second swiveling direction BD2, reverse to the first swiveling direction BD1. The actuation module 4 includes a scissor type handling mechanism having a stationary portion 4A and a portion 4B that is pivotable in a first pivoting direction PD1 and in a second pivoting direction PD2, reverse to the first pivoting direction PD1, with respect to a pivoting axle PV on the stationary portion 4A. The stationary portion 4A and the pivotable portion 4B are each provided with finger grips 14A,B to facilitate manual operation.
The shaft 2 includes an outer tube 7 that is rotatable relative to the shaft 2 and an inner tube, not visible in
The surgical device 1 further includes a coupling unit having a first coupling element 8A rigidly connected to the rotating tube 7 and a second coupling element, not visible in
The first unit 11 includes the actuation module 4 and the inner, stationary tube 5 indicated above. The stationary tube is fixedly connected to the actuation module 4. The stationary tube 5 is provided, at a distal end 5A thereof, with cut aways 6 for operational interaction with sliders as explained in more detail below. Further, the first unit 11 includes the second coupling element 8A mentioned above and rotatably mounted on the stationary portion 4A of the actuation module 4. The second coupling element 8A is rotatably driven by moving the pivotable portion 4B of the actuation module 4 in one of the pivoting directions PD1,2.
It is noted, generally, that the pin 16A,B can also be implemented as a bar preferably having a shape in conformity with the geometry of the corresponding spiral shaped slit 9A,B, thereby enlarging the contact area that the pin or bar 16A,B has in common with the corresponding slit, so that the rotary to linear linkage is firmer and/or has an improved wear resistivity.
In a process of assembling the surgical device 1, the second unit 12 and the third unit 13 are combined. In the combining step, a proximal end 10A is inserted into the distal end 7B of the rotatable tube 7 until the pins 16A,B are locked into the corresponding spiral shaped slits 9A,B, thus realizing a first rotary to linear linkage between the rotatable tube 7 and a first slider 15A, and a second rotary to linear linkage between the rotatable tube 7 and a second slider 15A. Then, a further combining step is performed wherein the first unit 11 is assembled by rotationally locking the sliders 15A,B relative to the stationary tube 5 such that a rotation of the rotatable tube 7 around the longitudinal axis L induces a movement of the sliders along the longitudinal axis L, in mutually opposite directions, thereby inducing a swiveling movement of the grasper beaks 3B,C in the first or second swiveling direction BD1, BD2. In the further combining step, the distal end 5A of the stationary tube 5 is inserted into the first coupling element 8a until a proximal portion 17A,B of the sliders 15A,B is received in the corresponding cut aways 6 of the stationary tube 5. Then, the first coupling element 8a rotatably engages with the second coupling element 8b in a rotational direction around the longitudinal axis L so that the actuation module 4 is driveably coupled to the rotatable tube 7 in a stable configuration. The sliders 15A,B can now still move in a longitudinal direction along the longitudinal axis L, but can not rotate relative to the stationary tube 5. Further, the inner rod 10 engages with the actuation module 4, the second coupling element 8b and/or the stationary tube 5 so that the inner rod 10 and the basic module 3A of the surgical module 3 is fixed along the longitudinal axis L.
In
By shifting the third unit 13 away from the second unit 12, as a next step in the process of de-assembling, the surgical device 1, the rotary to linear linkages between the rotatable tube 7 on the one hand and the sliders 15A,B on the other hand are disengaged, e.g. by moving the radially outwardly extending pins 16A,B from the spiral shaped slits 9A,B radially inwardly, so that the sliders 15A,B can be removed from the rotating tube 7, thereby de-assembling the second unit 12 and the third unit 13. During operation of the assembled surgical device 1, the user may actuate the actuation module 4 by pivoting the pivotable portion 4B in a pivoting direction PD1, PD2 with respect to the pivoting axle PV on the stationary portion 4A, thereby rotating the rotatable tube 7 relative to the shaft 2. Via the rotary to linear linkages, the rotatable tube 7 drives the sliders 15A,B into a movement along the longitudinal axis L, in mutually opposite directions, thereby inducing a swiveling movement of the grasper beaks 3B,C in the first or second swiveling direction BD1, BD2, thereby opening or closing the beak of the grasper.
The shaft 2 includes the rotatable tube 7, the stationary shaft 5 and the sliders 15A,B, forming a radial multilayer configuration. By rotatably locking the sliders relative to the stationary tube 5, the sliders 14A,B and the stationary tube 5 can be designed such that they form a single radial layer and can be integrated to some extend, thereby advantageously reducing the total number of radial layers in the shaft 2. In the shown embodiment, the stationary tube 5 and the sliders 15A,B snugly fit inside the rotatable tube 7, so that the stationary tube 5 is an inner tube and the rotatable tube 7 is an outer tube. However, in principle, in another design, the stationary tube 5 is an outer tube while the rotatable tube 7 is an inner tube.
The number of cut aways 6A,B corresponds to the number of sliders 15A,B, in the shown embodiment two sliders 15A,B, viz. for receiving a proximal portion 17A,B of a corresponding slider 15A,B. The received sliders 15A,B may shift along the longitudinal axis L in a forward direction F and a backward direction B, but are locked by locking elements 18A,B against rotation relative to the stationary tube 5.
Preferably, the contour of the cut aways 6 corresponds to the dimensions of the sliders 15. In the shown embodiment, the contour 19 of the cut away is generally rectangular shaped corresponding to the mainly rectangular shaped edge 20 of the slider proximal portion 17A,B. By matching the geometry and/or dimensions and/or external contour of the cut aways to the corresponding geometry and/or dimensions and/or external contour of the slider proximal portion, the slider can smoothly slide along the longitudinal axis L while being locked against rotationally movement, i.e. a movement in the circumferential direction C relative to the stationary tube 5. In the shown embodiment, the sliders have a curved geometry matching with the bending contour of the stationary tube 5. Further, the edge of the locking elements 18A,B may have a beveled shape thereby locking the sliders to move racially inwardly. Then, the pins are locked in the corresponding slits 9A,B, in the assembled state.
Advantageously, the stationary tube 5 and the sliders 15A,B form a substantially closed ring, in a cross sectional view at the received proximal portion of the sliders 15A,B, transverse to the longitudinal axis L. The ring is alternatingly formed by locking elements and sliders, respectively, thereby integrally forming a single radial layer in the radial multilayer structure of the shaft 2.
It is noted that the sliders 15 can be rotationally locked relative to the stationary tube 5 in another manner, e.g. by shaping the sliders and the distal end of the stationary tube 5 such that the sliders receive a single or a multiple number of longitudinally extending portions of the stationary tube.
It is further noted that, in principle, a rotary to linear linkage can be realized in a reverse constellation, i.e. by providing a pin radially extending from a rotatable tube into a spiral shaped slit provided in a slider. Further, the slider can be racially exterior to the rotatable tube. Further, the rotary to linear linkage can be implemented using other technical principles, e.g. using a screw linkage.
In the shown embodiment, the pivotable portion 4B of the actuation module 4 forms an actuation element driving the rotatable tube via the coupling unit 8. If desired, the actuation element can be designed in a different way, e.g. as a member that is movable along a linear, curved or straight path.
In another embodiment, the coupling unit 8 has a limited torque transfer for transferring a torque from the first coupling element 8a driven by the actuation element 4B to the second coupling element 8b driving the rotatable tube 7. By limiting the torque that is transferred by the coupling unit, the undesired occurrence of material fatigue or even breakage of surgical elements can be counteracted. Further, an undesired overload in force exerted by surgical elements on tissue can be counteracted. The coupling unit 8 having a limited torque transfer can e.g. be implemented using a friction coupling element. Further, the coupling unit 8 can be arranged for releasing the actuation element from the rotatable tube 7 if a force exerted on the rotary to linear linkage exceeds a predetermined level, for safety purposes.
Preferably, the surgical device is demountable as described above. However, in principle, the surgical device can also be formed as an integral unit.
The pitch of the spiral shaped slits 9A,B can be uniform, i.e. constant along its bending profile. The value of the pitch can be selected between a relatively small value so that the corresponding pin moves relatively small when rotating the tube, and a relatively large value so that the corresponding pin moves relatively quickly when rotating the tube. Further, the pitch of the spiral shaped slit can be non-uniform, i.e. varying as a function of the circumferential position of the slit. As a consequence, also the speed of the pin varies when rotating the tube with a constant rotation speed. As an example, the pitch of the slit may decrease at an end portion of the slit such that the speed of the corresponding pin reduces when reaching an end of its guiding path.
In the described embodiments, the surgical module 1 includes two movable surgical elements, viz. two beaks 3B,C, wherein the shaft 2 includes two sliders 15A,B forming a pair of sliders connected to the surgical module 3, each of the sliders 15A,B being operatively driven by the rotatable tube 7 via a respective rotary to linear linkage such that a rotation of the rotatable tube 7 around the longitudinal axis L induces a movement of both sliders 15A,B along the longitudinal axis L thereby inducing a movement of both movable surgical elements 3B,C. In the shown embodiment, the sliders 15A,B move in opposite directions. However, in principle, the sliders 15A,B may also move in the same direction, along the longitudinal axis L. Further, the surgical module 1 may include another number of sliders, e.g. a single slider, three or four sliders, for moving a corresponding number of surgical elements on the surgical module 3, i.e. a single surgical element or three or four surgical elements, respectively. Then, also the number of cut aways 6 in the stationary tube 5 corresponds to the number of sliders 15, each of the cut aways 6 receiving a proximal portion of a corresponding slider 15.
The surgical module 4 can be implemented as a grasper or another surgical module, e.g. a cutter module.
Advantageously, the step of realizing a rotary to linear linkage includes inserting a pin radially extending from the slider or rotatable tube into a spiral shaped slit provided in the rotatable tube or slider, respectively.
Further, the step of locking the slider may include receiving a proximal portion of the slider into a cut away extending along the longitudinal axis and provided in the stationary tube, at its distal end.
The invention is not restricted to the embodiments described herein. It will be understood that many variants are possible.
It is noted, as an example, that the shaft of the surgical device may include a further rotatable tube that is coaxial with the stationary tube, and a further at least one slider connected to the surgical module and operatively driven by the further rotatable tube via a further rotary to linear linkage such that a rotation of the further rotatable tube around the longitudinal axis induces a movement of the slider along the longitudinal axis thereby inducing a further movement of the surgical module, wherein the further at least one slider is rotationally locked relative to the stationary tube, thereby including two rotatable tubes that may, in dependently of each other, drive corresponding sliders for inducing movements of the surgical unit, e.g. in multiple degrees of freedom. In an embodiment, the cut aways corresponding to a first set of sliders driven by a first rotatable tube may be provided in a first longitudinal regime at the distal end of the stationary tube, while the cut aways corresponding to a second set of sliders driven by a second rotatable tube may be provided in a second longitudinal regime at the distal end of the stationary tube, staggered from the first longitudinal regime relative to the longitudinal axis.
These and other embodiments will be apparent for the person skilled in the art and are considered to fall within the scope of the invention as defined in the following claims. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments. However, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.
Number | Date | Country | Kind |
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2017954 | Dec 2016 | NL | national |
Filing Document | Filing Date | Country | Kind |
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PCT/NL2017/050824 | 12/8/2017 | WO | 00 |