Patent Application
20160331396
The present invention relates to the field of surgical instruments, especially to an axial handle for surgical instruments having a tubular shaft and to a surgical instrument preferably of the minimally invasive type.
In the field of surgery operations are frequently carried out in a way referred to as “minimally invasive”. Operations inside the body are in this case carried out by small incisions and by means of appropriate usually sophisticated instruments which are operated externally, i.e. from outside of the patient's body by the operating surgeon. For the patient this means less strain during operation, as no big cuts have to be carried out, i.e. the wounds are kept very small. This method is applied in cardiosurgery, laparoscopy (intra-abdominal examination), arthroscopy, for example. Manipulative operations such as the collection of tissue specimens or the removal of organs (e.g. removal of the gall bladder) are possible by this method.
For this purpose, so called instruments having a tubular shaft are utilized. Such instrument having a tubular shaft usually includes a preferably hollow instrument shaft to the distal end of which a (tubular shaft-type) tool, for example in the form of scissors, fixation forceps, needle holder or similar mechanically operable actuators, is articulated by which the operating surgeon may operate on the patient. For this, at the proximal end of the instrument shaft a device in the form of an operating handle is provided which enables a force/moment that has to be applied for actuating the tool to be introduced to a force transmission train preferably inside the instrument shaft, the force transmission train then transmitting the introduced force/moment to the tool to actuate the same.
There exist specific operating handles in the form of handles which are adapted to be coupled to the described instruments or are fixedly mounted thereto for actuating the tool. High requirements in terms of cleaning, dismounting, stability or tactile behavior are made to such handles.
A surgical handle for a surgical instrument of the afore-mentioned design usually consists of a handle housing which is connectable/connected to the instrument shaft and accommodates a mechanism for force/moment transmission to the force transmission train operatively connected to the tubular shaft-type tool, of levers/handles articulated to the handle housing which are manually operable and are in operative connection with the mechanism, of a distal connecting device, where appropriate, via which the handle can be connected to the instrument shaft and the force transmission train can be connected to the mechanism inside the housing and of a gear system preferably in the form of toggle means which couples the levers/handles to the mechanism inside the case for actuating the latter.
In case that the handle is a pivoted lever articulated to be pivoting on the handle housing, a toggle is articulated at one end thereof to a central portion of the pivoted lever, wherein the other end thereof is articulated to a sliding element or push/pull rod supported to be axially movable in the handle housing which sliding element in turn is coupled to the force transmission train (e.g. a push/pull rod or Bowden cable inside the instrument shaft).
When the pivoted lever is manually pivoted toward the instrument housing, an axial displacement is imparted to the sliding element via the toggle to actuate the distal instrument tool. For returning the pivoted lever into its starting position, on the sliding element and/or on the pivoted lever itself a return spring is arranged which is tensioned upon manual operation of the pivoted lever and returns the pivoted lever when it is released.
A possibility of generating the restoring force for the handles resides in an axial compression spring (coil spring) which is installed in the handle housing and axially resets the sliding element to the initial position when the operating force manually applied to the handle is reduced. The axial compression spring installed in the handle housing requires space, however. Apart from that, the spring force acts only downstream (distally) of the toggle transmission, viewed in the direction of force. In this way, depending on the angular position of the toggle and thus of the operating handle, the impact of the spring force is strongly reduced. When the tool is almost closed, the impact of the spring force is strongly dropped and may result in the tool snapping shut in an undesired as not controllable manner.
Therefore, handles available on the market having the afore-described conceptual design exhibit various restrictions. For example, the handles for tubular shaft-type instruments frequently cannot be dismounted due to their complicated mechanism. Apart from that, the tactile behavior with available handles having the afore-described structure is not optimal or gets even largely lost, because the spring is connected downstream of the toggle mechanism.
A second variant consists in the arrangement of a spring on the handle itself, i.e. between the handle housing and the operating handle, as it is also realized in known scissors designs, for example. The spring force in this case acts directly between the handle housing and the operating handle and thus upstream of the toggle mechanism when viewed in the direction of force. In this case the handle must have high rigidity, however, which accordingly entails high weight.
WO 2013/079340 discloses a surgical handle in which a sliding element is axially displaced inside a handle housing by means of a joint element in the form of a toggle so as to actuate a downstream force transmission train. Handles/levers that are engaged in the joint elements are forced toward each other and act on the sliding element via the joint elements. The restoring force acting on the handles is generated by an axial compression spring that is seated in the handle housing and acts on the sliding element. In addition, the handle includes stop elements axially acting on the sliding element for restricting the actuating path thereof that are intended to prevent the toggle mechanism from reversing. This means a mounting effort for the additional parts, higher weight and more gaps that impede cleaning of the device.
US 2008/064929 A1 discloses an axial handle for a tubular shaft-type instrument in which the restoring force acting on the actuating levers is generated via leaf springs each of which forms an integral part or a longitudinal portion of the actuating levers. The actuating levers are solid and consequently heavy which is a drawback in handling the instrument during an operation.
In the following sections, the term “proximal” is used as “being close to the handling person” and the term “distal” is used as “being distant from the handling person”.
It is the object of the invention to avoid the afore-mentioned drawbacks and to provide a surgical handle as well as a surgical instrument which provides clear tactile feedback to the operator, offers the option of simple dismounting and can be easily cleaned.
This object is achieved by a surgical handle comprising features described herein as well as by a surgical instrument comprising the features described herein.
According to a first aspect, the core of the present invention consists in the provision of a surgical handle for a surgical instrument, especially a shaft-type instrument, for actuating a tool arranged distally on an instrument shaft comprising a handle housing to which at least one lever/handle is mounted to be movable/pivoting relative thereto, the lever/handle being coupled via a toggle mechanism to a sliding element that is axially movable in the handle housing so as to move the sliding element by operating the lever/handle from the starting position thereof against the restoring force of a spring element and in this way to operate the tool. In accordance with the invention, the toggle mechanism is constituted by a resilient element, or in other words, the toggle lever simultaneously forms the resilient element for generating a restoring force on the lever/handle.
Due to this measure, the arrangement of an additional separate spring element for restoring the lever/handle may be dispensed with, which saves space in the design that can be used for other purposes, ensures simpler dismounting of the handle and guarantees better cleaning of the handle and thus of the instrument by a reduced number of narrow interstices.
It is favorable when the surgical handle comprises a first lever/handle which is swivel-mounted about a pivot axis aligned transversely to the handle axis on the handle housing. The swivel-mounting of the first lever/handle permits the clearly defined and user-friendly movement thereof relative to the handle housing. In order to achieve a compact design of the handle the first lever/handle is swivel-mounted directly on the handle housing. The term “transversely to the handle axis” means that it is provided in a plane perpendicularly to which the handle axis is oriented.
Concerning the handling it is advantageous when the first lever/handle is swivel-mounted with its proximal end and is pivoting relative to the handle housing with its distal free end. In this way the first lever/handle may be seized and operated more easily by the user.
Preferably the first lever/handle is swivel-mounted on or close to a proximal end of the surgical handle, for in this way it is possible to impart a compact design to the surgical handle.
The first lever/handle preferably can be transferred from a braced position relative to the handle housing which it adopts in the non-operated position (starting position) to an approximated position relative to the handle housing which it adopts in the at least one operating position, and vice versa. For operating the surgical handle the first lever/handle may be transferred from the braced position to the approximated position while pivoting relative to the handle housing. This facilitates a user's handling of the surgical handle.
It is favorable when the first lever/handle can be fixed in at least one actuating position, for this entails the possibility of fixing also the sliding element and thus the force transmission element at one position. For example, this is favorable when claw parts for seizing body tissue or a surgical instrument such as a needle are arranged at the distal end of the tubular shaft-type tool.
The force is generally transmitted to the tubular shaft-type tool via the toggle transmission. In a conventional toggle transmission the transmitting element between the handle and the sliding element is configured to be non-resilient, therefore the resetting of the lever/handle has to be generated via an additional elastic element, preferably a spring. Hence it is intended to manage on fewer components and to avoid the drawbacks of a rigid toggle lever.
The invention so-to-speak combines the function of the toggle lever that is rigid per se with the characteristic of the resilient element. In other words, this element unifies the characteristics of the rigid toggle and the spring within one component, thus providing additional space in the handle housing which can be used otherwise, for example for improving the coupling device to the tubular shaft-type instrument. This saves manufacturing costs during assembly and facilitates cleaning due to fewer gaps.
The combination of the two functions of a toggle transmission and a return spring is taken over, according to the invention, by one single component, preferably a leaf spring that replaces the rigid toggle lever according to prior art.
A leaf spring in general has a substantially elongate shape including first and second ends. At least at one end the leaf spring may include means for fastening by which it can be fastened to a counter piece, preferably the lever/handle and/or the sliding element.
The means for fastening to one or both ends of the leaf spring may be configured so that they ensure a rigid connection relative to the object to which they are fastened or else a movable/pivoting connection relative to the object to which they are fastened.
Said means may be, for example, holes for screws and rivets, thickened portions of the material at ends of the leaf spring, widened portions, ends of the leaf spring bent to form eyelets or similar means.
The object (sliding element/handle) to which the leaf spring may be fastened itself provides means that correspond to said means at the ends of the leaf spring and support a connection to the fastening means at the ends of the leaf spring.
Said means may be for example screw threads, axes of rotation, clamping slits, clamping slits including a blind hole, groove/tongue connection and similar means which are suited for connecting the end of the leaf spring to the object.
Moreover, adhesive, soldering and welding connections may be added, for the purpose of assistance or on their own, to the afore-mentioned means so as to connect the end of the leaf spring to an object (sliding element/handle).
Preferably the leaf spring is expanded linearly and along a longitudinal axis. The width of the leaf spring is larger than the thickness/height.
The thickness of the leaf spring may be selected independently along the length of the leaf spring to achieve a desired spring characteristic.
The width of the leaf spring is homogenous at least in portions.
The leaf spring may have areas in which the width/thickness ratio of the spring varies so as to achieve different spring characteristics.
For assembly it may be favorable when the width of the leaf spring decreases toward one or both ends.
The leaf spring may also take a curved shape in the stress-free state so that an (imaginary) connection between the ends of the leaf spring is shorter than the length of the leaf spring itself (arc shape).
The radius of curvature of the leaf spring may be homogenous in portions. Equally, the curvature of the leaf spring may have plural different radii of curvature (while maintaining the arc shape) so as to obtain protection against overload, for example.
The handles or else levers or else handle shells include upper and lower surfaces, wherein an upper surface is facing the palm of a hand and a lower surface is facing away from the palm. Each lever/handle includes means for introducing a force to the leaf spring so as to deform the leaf spring in order for the latter to store energy required for resetting the handle into an initial position.
These means may be arranged on the surface facing away from the palm, i.e. on the surface of the handles facing the handle housing. The force application means may act on a spot or the full surface of the leaf spring in the central portion thereof, for example such that an initially pre-curved (arc-shaped) leaf spring is resiliently deformed with increasing actuation of the lever/handle into the straight position so as to return to the curved shape again when the lever/handle is released and accordingly to swivel the lever/handle back into the initial position (starting position) and at the same time to withdraw the sliding element. The force application means may adopt the shape of a projection, for example, on the respective lever/handle, the projection being adjacent to a central portion of the leaf spring (resilient toggle lever) and pushing the latter through upon actuation of the lever/handle, or may be sort of a link guide along which the leaf spring rolls off and accordingly expands.
The force application means may contact the leaf spring without any force application when the handles are unloaded, i.e. in the initial state.
The leaf spring according to the invention may be formed of suitable elastic materials such as e.g. spring steel, plastic material, fiber-reinforced plastic material.
The fact that upon compressing the handle a continuously increasing spring tension is generated renders an additional compression spring superfluous. By an appropriate shape of the leaf spring an overload protection can be additionally achieved which is especially desired for protecting the sophisticated instruments.
For example, the leaf spring may be curved more strongly compared to the arc shape at a spring end portion preferably in the area of the sliding element (radius is narrower than in the residual spring portion) so that said spring portion having a smaller bending radius bulges upon reaching or exceeding a particular axial force acting on the leaf spring (according to the general toggle function) and thus restricts the axial force transmission from the lever/handle to the sliding element.
The handle according to the invention preferably comprises a second lever/handle so as to facilitate the user's handling of the handle. Preferably it may be provided that the second lever/handle is immobilized on the handle housing as in this way a simpler constructional design can be imparted to the handle.
The second lever/handle may as well be movable and may be swivel-mounted on the handle housing, analogously to the first lever/handle, about a pivot axis aligned transversely to the handle axis. Furthermore the second lever/handle may be operatively connected to the sliding element by a toggle lever so as to transmit an actuating force (axial force) to the sliding element. Of preference, for connecting the second lever/handle and the sliding element equally the resilient element according to the invention, and in particular a leaf spring, is employed.
When realizing the handle in practice it turns out to be favorable when the first lever/handle and/or the second lever/handle take a shell shape and enclose at least portions of the handle housing especially in sleeve shape in the circumferential direction of the handle axis. The levers/handles are arranged on two opposite sides of the handle axis, for example, and may be seized and operated more easily by the user's palm.
Furthermore, it turns out to be advantageous when each of the first lever/handle and the second lever/handle are configured as axially extending semi-cylindrical or substantially semi-cylindrical shells receiving the handle housing there between.
The invention shall be illustrated in detail hereinafter by way of preferred embodiments with reference to the accompanying drawings.
On a distal end of the lever 1 a toggle 4 is equally swivel-mounted about an axis 3b. Furthermore, the toggle 4 is pivoting relative to a sliding element 5 about an axis arranged on the sliding element 5.
A spring 6 is mounted in a proximal position between a stop 7 in the proximal part of the handle housing 2, 2a and the sliding element 5 which is provided inside the handle housing 2, 2a.
In the exemplary representation of
In
When the lever 1 is pressed down, the toggle 4 movably connected thereto and thus also the sliding element 5 movably connected to the toggle 4 moves in the axial direction thereof. The lever 4 is referred to as toggle in this arrangement and represents a rigid non-flexible connection.
The more the lever 1 is swiveled about the axis 3 toward the handle housing 2, 2a, the more the toggle 4 moves the sliding element 5 against the force of the spring 6. The spring 6 can apply a restoring force to the lever (the handle part) 1 only as long as the lever 1 and, respectively, the lever 4 do not fall below a minimum angle with respect to the handle axis (parallelogram of forces). It has always to be ensured that an upwardly directed force acts on the lever 1. If the toggle 4 arrived at a position in parallel to the handle axis 8, no more upwardly directed force would be provided and the toggle 4 would remain in its position. The surgical handle in such moment so-to-speak would snap shut and thus also maintain the tool arranged at the distal end of the tubular shaft in the closing position.
The second equally disadvantageous variant of the state of the art is exemplified in
In
The spring element 9 preferably may be curved (arcuate). When the lever/handle 1 is swiveled about the axis 3 in the direction of the handle housing 2, 2a and the angle enclosed between the lever/handle 1 and the handle housing 2, 2a is reduced, the distance between the ends A and B of the leaf spring 9 is continuously increased. This means to the leaf spring 9 that it is deflected out of the arcuate curved state, which represents its idle position, in the direction of the straight alignment and thus absorbs energy for resetting the handles 1.
The connection both to the sliding element 5 and to the operating handle 1 may be configured as pivot axis (3a, 3b); however, also a rigid connection relative to each of the handle 1 and the sliding element 5 is possible. A combination of both fastening options is imaginable as well.
The expansion of the leaf spring 9 during swiveling the handle lever 1 about the pivot axis 3 in the direction of the handle housing is brought about by the fact that portions of the leaf spring 9 adapt to (roll off) part of the handle 1 facing the handle housing and hence are straightened, i.e. experience an expansion. By the expansion of the leaf spring 9 and by swiveling the lever 1 the sliding element 5 connected to the end of the leaf spring 9 is axially moved along the handle axis 8.
The lower part of the handle 1 facing the handle housing may also include force application means 13 (projection/journal etc.) as shown in
When swiveling the handle 1 about the axis 3, the projecting force application means 13 enters into contact with the leaf spring 9 and upon further swiveling about the axis 3 at this location the force is applied to the leaf spring 9 and causes the afore-described expansion (
As far as the function of the resilient toggle lever 9 according to
At the start of actuation the shown lever 1 is provided in the swivel-out position and the sliding element 5 is accordingly provided in the retracted position. When based on this fact the lever 1 is swiveled in the direction of the handle housing, the sliding element 5 is displaced over the toggle (C-shaped leaf spring) 9 along the axis 8. The leaf spring 9 continuously rolls at its central portion off the projection 13 which elastically indents and thus straightens the leaf spring 9 in the central portion with an increasing degree of actuation. When the lever 1 is released, the energy stored in the leaf spring 9 causes the leaf spring 9 to automatically return to the pre-curved shape. Accordingly, the lever 1 is swiveled back to its initial position and axially pulls the sliding element 5 back to the original position thereof.
In
The sliding element 5 and the leaf spring 9 in this case may be a non-dismountable part that is to be delivered in complete form.
In this constellation the leaf spring 9 may preferably be straight. In order to achieve the restoring effect, the terminal points A and B of the leaf spring 9 do not move apart from each other during swiveling of the handle 1 about the axis 3 as in the preceding embodiment, but move toward each other due to increasing elastic bending of the leaf spring 9. The one end A of the leaf spring 9 may abut against a stop 15 arranged on the surface of the handle 1 facing away from the palm or the leaf spring 9 is hinged to the lever 1. The stop 15 (or hinge) prevents the end A of the leaf spring 9 from moving relative to the handle 1 when the handle 1 is compressed. The stop 15 (or hinge) thus ensures the force application and hence the deformation of the leaf spring 9 when the handle 1 is swiveled about the axis 3. At the same time, an axial force is transmitted to the leaf spring 9, thus causing the sliding element 5 to be displaced along the axis 8.
Additional force application means 13 as mentioned in the previous embodiment are not required, but can be added as required, e.g. in order to achieve a particular characteristic in the force path. In order to achieve a particular characteristic of force application it is also possible to arrange the leaf spring 9 at an angle relative to the sliding element 5, wherein the imaginary pivot axis about which said angle rotates is in parallel to the axis 3. The characteristic of force application depends on the respective fixedly selected angle.
Further imaginable is a connection not illustrated here which is only clamped, for example, hence without either of the ends of the leaf spring 9 including any particular fastening means. In the simplest case, the sliding element 5 may have a slit into which the one end of the leaf spring is clamped.
A connection between the leaf spring 9 and the sliding element 5 can be achieved by soldering, gluing or clamping, depending on the material.
In
It would reach its maximum rigidity if it were aligned in parallel to the handle axis 8. Although this extreme case cannot occur, as the axis of rotation 3 of the handle 1 is not located on the handle axis 8 but on the handle housing 2, 2a, in this bending state, however, when manual actuating force is further applied to levers/handles 1, the leaf spring 9 can transmit so much force via the gear mechanism to the distal end of the tubular shaft-type tool that the sophisticated tools might be damaged. Damage of the coupling means is also possible at the proximal end of the tubular shaft-type tool.
The additional curvature 10 of the leaf spring 9 in the illustrated area may produce relief. In
If the force continues increasing in the direction of the handle axis 8, cf.
When the handle 1 is released or the manual actuating force on the levers/handles 1 is reduced, at first the sliding element 5 does not move back, but the leaf spring 9 initially reduces the additionally obtained energy by reverse-bending the deformation/bulging 14 into the state shown in
a illustrate in detail the leaf spring 9 according to the invention without (
Accordingly, the levers 1 hinged to the handle housing 2 having a cylindrical shape in this case are shaped as lever shells that are extremely rigid. On the sides of the lever shells facing the handle housing 2 link-shaped notches are visible on which the leaf springs 9 pre-bent in C-shape rest in the central portions thereof upon actuation of the levers 1 and in this way are resiliently pressed to become straight. Simultaneously, via the leaf springs 9 a thrust force is transmitted to the sliding element 5 which is supported and guided to be sliding in the handle housing 2. The force transmission mechanism represented in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 100 603.8 | Jan 2014 | DE | national |
This application is the United States National Phase entry of International Application No. PCT/EP2015/050538, filed Jan. 14, 2015, which is related to and claims the benefit of priority of German Application No. DE 10 2014 100 603.8, filed Jan. 21, 2014. The contents of International Application No. PCT/EP2015/050538 and German Application No. DE 10 2014 100 603.8 are incorporated by reference herein in their entireties and for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/050538 | 1/14/2015 | WO | 00 |
