DE102007030856B3 - Surgical instrument e.g. scissors, for minimally invasive surgical procedure in patient, has piston sections with outer diameter smaller than inner diameter of shaft, and sealing element everted by formation of rolled sealing section - Google Patents

Abstract

The instrument (10) a force-transferring unit (22) including pistons (36, 48) and a fluid section, which is separated from the pistons by a sealing element (68). Piston sections (38, 50) include an outer diameter which is matched to an inner diameter of a shaft (12) i.e. pipe. One of the pistons includes piston sections (40, 54) which stand away from the sections (38, 50) in a direction of the fluid section. The sections (40, 54) include an outer diameter which is smaller than the inner diameter of the shaft. The sealing element is everted by formation of double-layered rolled sealing section.

Description

The The present invention relates to a surgical instrument with a Shank, at least one movably mounted tool element comprehensive end effector and one in the shaft in distal and proximal Direction movably mounted power transmission member for transmitting an actuating force introduced at a proximal end of the instrument on the end effector for moving the at least one tool element from a first to a second tool element position and / or vice versa, wherein the power transmission member at least one displaceably mounted in the shaft and a piston separated from the at least one piston by a sealing element Fluid portion which is filled with a fluid, which can be pressed by pressurization against the sealing element for moving the at least one piston bearing against the sealing element parallel to the longitudinal axis of the shaft.

Surgical instruments of the type described in the introduction are preferably used in minimally invasive surgery in order to be able to carry out surgical interventions inside a patient's body without having to open the body invasively. Examples of such instruments are, for example, in DE 195 37 320 C2 described. An end effector can be designed, for example, in the form of a gripping device or a cutting device.

Around to be able to train such instruments particularly small, with Outer diameters the shafts smaller than 5 mm, preferably in a range between 2.5 mm and 4 mm, are conventional power transmission members in the form of push and pull rods unsuitable. This is partly because because they have a stability reasons must have certain minimum diameter, and on the other hand because of an articulation of the tool elements in rod-shaped power transmission members always having a certain amount of play.

From the US 5,779,727 is a hydraulically operated surgical scissors known. The DE 920 741 4 U1 is concerned with a surgical instrument having at least one movable by means of a drive working member, which is arranged at the end of a catheter, through which the drive is actuated. A surgical instrument with a tube through which a transmission element passes is in the DE 422 064 4 C1 described. The US 6,099,535 relates to a hydraulically actuated multiple belt ligator. A hydraulically operated tweezers is in the US 3,266,494 described.

It is therefore an object of the present invention, a surgical Instrument of the type described above to improve so that a power transmission low backlash on the end effector and with high efficiency is possible.

These Task is in a surgical instrument of the type described above Type according to the invention thereby solved, in that the at least one piston has a second piston section which pointing from the first piston portion in the direction of the fluid portion protrudes and an outside diameter which is smaller than an inner diameter of the shaft, and that the sealing element umstülpbar is to form a double-layered rolled sealing section.

The fluid section in particular makes it possible in a simple manner to provide mechanical separation between an actuating device which can optionally be arranged at the proximal end of the instrument and the end effector. Furthermore, the fluid portion can be made significantly smaller in cross-section, as a shaft with a power transmission member in the form of a push and / or pull rod. As a result, in particular outer diameter of the shaft can be realized not only smaller than 15 mm, but even smaller than 5 mm, in particular even smaller than 3 mm. Furthermore, it is conceivable to form the end effector and the piston as a unit, which in particular allows the use of the instrument due to simple production and associated reduced manufacturing costs as a disposable instrument. Preferably, the fluid is a substantially incompressible fluid such as water, a physiological saline or an oil. Conceivable are fluids in the form of mixtures or emulsions, wherein the fluid is favorably biocompatible. For optimum power transmission, it is favorable if the fluid also fills the fluid section without bubbles in order to enable a play-free power transmission. The fluid section also maximizes friction transmission from a proximal end to a distal end of the instrument, even with very long shafts. Furthermore, a power transmission works equally well in curved or multi-threaded shafts as well as straight shafts, which is not the case with power transmission members in the form of push and / or pull rods. Furthermore, the proposed development allows the formation of a fluidic, in particular hydraulic or pneumatic, Kraftübertra supply in a preferably leak-free cylinder-piston system, wherein the shaft in connection with the sealing element quasi defines a cylinder in which the piston is movably mounted. Furthermore, the proposed fluid section can in principle be combined with any desired, preferably low-backlash and low-friction end effectors. To have a good guide of at least ei NEN piston in the shaft, it is advantageous that the at least one piston comprises a first piston portion which has an outer diameter adapted to an inner diameter of the shaft. Thus, the at least one piston can be moved virtually free of play in the shaft parallel to the longitudinal axis and / or rotated about it. Characterized in that the at least one piston has a second piston portion which protrudes from the first piston portion pointing in the direction of the fluid portion and having an outer diameter which is smaller than an inner diameter of the shaft, in particular can be an effective surface, against which by the sealing element presses fluid separated from at least one piston, set in the desired manner.

Preferably includes the power transmission member two pistons passing between each other through the pistons a sealing element separated fluid section distal and Limit on the proximal side. In this way, a self-contained Form fluid section, in the example with the proximal side a force is applied to a first piston and through the fluid transmitted a second, distal-side piston and the end effector can be forwarded. Of course, it would also be conceivable on the Provisional piston to dispense and the fluid by means of a Pump using a surge tank in the fluid section to press.

advantageously, the fluid section comprises a fluid space which is completely closed and is sealed. Preferably, a leakage-free working pressure relief valve provided to form a force limit for the instrument. Further It may be advantageous if a degassing system for degassing the fluid is provided. This allows the fluid section to be gas-free and thus virtually incompressible depending on the choice of fluid make and thus realize a backlash-free power transmission. Optionally, one or both Seal elements to be connected to the respective piston. This allows in particular a movement of the distal-side piston under both thrust as under tension by appropriate movements of the proximal side Piston. Furthermore, a surge tank can be advantageous if by a corresponding movement, a volume of the fluid portion of something may vary, causing a bubbling in the fluid leading to a play-related power transmission to lead can, is prevented.

Of the Construction of the surgical instrument will be particularly easy if a case the fluid space defined by two sealing elements and the shaft is. In particular, lets so the fluid space in one piece training or by an appropriate composite material. The fluid space can be so when making directly into the stem with the sealing elements be integrated, which simplifies the production and also makes it cost-effective.

Of the Structure of the instrument further simplifies if the at least a piston is coupled directly or indirectly to the end effector for moving the at least one tool element as a result of a Movement of at least one piston in a more proximal and / or distal direction Direction. In particular, it is possible, the piston and the end effector as a unit, that is especially in one piece, to train. Therefor Plastics are particularly suitable, for example, a production in one or a few steps.

advantageously, the sealing element is flexible. Such a sealing element allows one at least partially movement of the sealing element in parallel to the longitudinal axis in the distal and / or proximal direction about an actuating force to transfer from the fluid to the at least one piston or vice versa.

conveniently, the sealing element is inelastic. The sealing element of a inelastic or inelastic material, prevents an unwanted expansion of the fluid section and thus the most unfavorable Case, namely a destruction by bursting or bursting, whereby the fluid can be released. In addition, will by an inelastic sealing element a backlash of power transmission secured.

The Seal element is particularly easy to manufacture when in Form of a fluid-tight membrane is formed. In addition, can Such a membrane is preferably flexible and inelastic become. Furthermore, a membrane can be made particularly thin become. Preferably, it has a wall thickness smaller than 0.5 mm is. A flexibility the same is further increased, if they are preferably thinner executed as 0.1 mm is. conveniently, she is thinner than 0.05 mm.

In order to achieve the greatest possible displacement of the at least one piston, it is advantageous if the membrane forms a bellows or a rolling bellows. In particular, a rolling bellows allows a particularly large displacement of the at least one piston, which corresponds in particular to a maximum of twice the length of the rolling bellows parallel to the longitudinal axis. Furthermore, it is also possible to force-free form joints of the sealing element with the shaft and / or the at least one piston, that is, joints do not necessarily have to define stops for movement of the at least one Kol bens.

Especially simply the construction of the sealing element, if it is a sleeve-shaped first Section has, which is closed on one side. A sleeve-shaped section let yourself especially in a simple way inside or outside arrange a shaft and connect with this. Him too one-sided close is cheap, because so the fluid portion can be sealed relative to the shaft and the sealing element abut the at least one piston. Especially The first section may also be defined by the at least one piston or a part thereof, for example one in the direction of the fluid portion facing surface, be formed. In this case, it is advantageous if the sealing element permanently fixed and fluid-tight with the at least one piston is connected.

Advantageous is it if an outside diameter of the first portion corresponds to an inner diameter of the shaft or substantially corresponds. This makes it possible in particular, the first section on an inner wall of the shaft, without to have to stretch the first section.

One optimum contact of the sealing element on at least one piston let yourself in a simple way achieve that the first section through a transversely or substantially transversely to the longitudinal axis of the shaft extending second portion of the sealing element is closed. Especially can the first and second sections are integrally formed and free from be any joints or seams.

Preferably For example, a surface area defined by the second section essentially has the Size one inner free cross sectional area of the Shafts up. This embodiment allows optimal efficiency in the transmission an actuating force from the fluid to the at least one piston. Here is the diameter the free cross-sectional area preferably smaller than 15 mm, favorably smaller than 5 mm and advantageously less than 3 mm. A relationship between a height, this means a length the first portion parallel to the longitudinal axis, and a diameter of the second section is conveniently greater than 0.2, preferably greater than 0.5. It is particularly advantageous if the ratio is greater than 1. The bigger that Relationship, the bigger one maximum possible Displacement of the at least one piston parallel to the longitudinal axis.

For an optimal power transmission from the fluid to the at least one piston, it is advantageous if the sealing element is designed and arranged such that the second section parallel to itself in the direction of the longitudinal axis is movable. Depending on the length the first section parallel to the longitudinal axis, it may then be possible that the sealing element rolls up. Preferably, it is in shape a rolling bellows and thus allows a parallel movement to yourself in a simple way too.

conveniently, the sealing element is fixed fluid-tight on the shaft. In order to can undesirable Fluid losses are avoided. It also simplifies things the structure of the sealing element, because it does not necessarily recordings be provided, such as for sealing rings to a movement prevent the same relative to the shaft or to the sealed part. Furthermore, it is also possible to form the sealing element and the shaft in one piece.

On particularly simple way the sealing element set on the shaft, if there is an annular edge having. In particular, it can be fixed with the edge on the shaft be. Thus, in particular a second existing section on the sealing element, which is transverse to the longitudinal axis extends, in the direction of the longitudinal axis to be moved.

Around one possible huge Displacement for to allow the at least one piston, it is advantageous when the sealing member is formed such that the first Inverted section is under education one of the edge pointing away and in one of the Edge-facing direction closed double-ply rolled Seal portion. The sealing portion is preferably formed by completely or partially folded back or folded or everted first Section of the sealing element. An everting in the manner described is particularly easy, if a wall thickness the sealing element as possible is small and a relationship between a length of the first section and a diameter of the second section preferably large.

Preferably the sealing element is designed and arranged such that the second section is movable on the proximal and distal sides of the rim is. This is possible in particular if the sealing element umtülpbar is formed, that is, when the first portion of the sealing element at least partially foldable back on itself and a two-ply Forming seal portion, wherein between the two layers the first portion remains filled with the fluid annular fluid space.

A particularly compact construction of the surgical instrument can be achieved by that the edge is fixed to an inner wall of the shaft.

alternative It can also be cheap be if the edge is on an outside wall of the shaft. This arrangement facilitates in particular a mounting of the sealing element on the shaft when a diameter of the shaft is very small. Optionally, in this case further a short outer shaft provided be at least one connecting area between edge and Sheath covered outside and over an entire length the sealing element in the direction of the at least one piston extends and is also so long that the at least one piston in the outer shaft section sure about at least a part, preferably its entire displacement guided is.

Especially easy and inexpensive can be produced the sealing element by a thermoforming process.

Advantageous it is when the sealing element by deep drawing, hot blasting, Shape, Extrude or injection molding is made. In particular, it is possible to use this non-exhaustive list to perform thermoforming process while the sealing element directly to the stem. In particular, the thermoforming processes be performed directly after the formation of the shaft to a unit to form of sealing element and shaft.

Especially when the sealing element is manufactured separately from the shaft, it is advantageous if the sealing element by thermal weld together is fixed to the shaft at this. Thermal welding allows for easy and safe way a permanently stable and fluid-tight connection between the sealing element and the shaft.

alternative or additionally It can also be cheap be when the sealing element by gluing or jamming is fixed to the shaft at this. For example, a Clamping ring an edge of the sealing element between itself and the Keep the shaft clamped, both on an inner wall and one outer wall of the shaft.

A Connection of the sealing element and the shaft simplifies, when the sealing member and the shaft of the same material are made.

Of the Structure of the instrument leaves further simplify when the at least one piston related on the longitudinal axis is formed rotationally symmetrical. In particular, too two identical pistons may be provided to distally the fluid section and on the proximal side.

Around to simplify manufacture and assembly of the instrument it cheap, when the first piston portion directly or indirectly with the end effector coupled or in one piece is formed with this. In particular, one-piece training, for example by injection molding and other shaping methods, allows the formation of a stable unit of the first piston portion and the end effector.

conveniently, is the second piston portion surrounding an annular space formed. The annulus allows it the sealing element, with a everted sealing portion, formed by the first section to dip into the annulus. This is preferred the second piston portion coaxial with the longitudinal axis on the first piston portion arranged distantly.

Preferably the annulus is dimensioned such that at least partially inverted Sealing element can dip into the annulus, without getting in it to jam. This means that a width of the annulus all the more to be taller must, the bigger one Wall thickness of the sealing element and vice versa. Edges of the second piston section are preferably rounded, so that damage to the sealing element safely can be avoided.

advantageously, the annular space is further dimensioned such that the double-layered rolled sealing section can dip into the annulus, without to get stuck in it. Thus, a safe function of the surgical Instruments permanently ensured.

Cheap is it, when the second piston portion parallel to the longitudinal axis is about half as long as the first portion of the sealing element. This dimension ratio to ensure that even the everted sealing element with his Sealing section completely immerse in an annulus surrounding the second piston section can, whereby jamming of the sealing element during movement of the at least one piston is reliably prevented.

In order for pressure equalization to take place between both ends of the piston, it is advantageous if the at least one piston is provided on one outer side with a surface structure such that a gas exchange between its two ends is made possible if the at least one piston is arranged in the shaft. To provide such a surface structure, ie in particular a fluid connection between the two En which produces the at least one piston, prevents compression of a gas, in particular of air, which could result in an additional clearance when moving the at least one piston and the end effector connected thereto.

Of Further, it is convenient when a shank inner wall is so having a surface texture is provided that a gas exchange between both ends of at least allows a piston is when the at least one piston is arranged in the shaft. This arrangement and design of a surface structure is used for training a fluid connection that is a compression of an enclosed Gas prevents. this makes possible as well as the formation of a surface structure on the at least a piston, a faster and more direct piston movement without play.

Especially Easy to manufacture is the surface structure, if this at least a recess which provides fluid communication between the two Produces ends of at least one piston. It can too two or more recesses may be provided, both in a shaft inner wall as well as on an outer surface of the at least one piston, in particular of the first piston section.

Around a defined movement of the at least one piston relative to Ensure shank is preferably a guide device to lead a movement of the at least one piston in the shaft parallel to longitudinal axis intended.

advantageously, forms the guiding device an anti-rotation device for preventing rotation of the at least a piston in the shaft about the longitudinal axis. Of course the rotation can also be provided separately from the guide device be. Provide the rotation prevents in particular tensile loads, at the joints between the sealing element and the at least a piston and / or the shaft can act. In particular, so can torsional forces acting on joints are prevented.

The guide means can be easily formed by first and second interacting guide members one of which is on at least one piston and another is arranged on the shaft, and that the first guide member in the form of a guide projection and the second guide member in the form of a guide recess is trained. The guide members the management facility can in particular in one piece be connected to the respective component of the instrument, they assigned. By appropriate shapes, the guide recess and the guide projection one defined guideway for one Specify relative movement of the at least one piston and the shaft.

advantageously, is the guide recess in the form of a guide groove extending parallel to the longitudinal axis educated. This can be on the one hand a defined leadership for one Specify movement of the at least one piston relative to the shaft and simultaneously form an anti-rotation, which is a rotation the at least one piston about a longitudinal axis of the shaft is effective prevented.

According to one another preferred embodiment the invention can be provided that the sealing element, the at least one piston and / or the shaft of one or more the materials polyethylene (PE), polyurethane (PU), polyethylene terephthalate (PET), polycarbonate (PC), polypropylene (PP) are made. The Production of the surgical instrument from a plastic, in particular one or more of said plastics, simplified its manufacture, lowers the manufacturing cost and thereby allows the training of a cost-effective Once the instrument. Furthermore let the parts of the instrument, which consist of one or more said materials are made in a simple manner with each other connect, especially during the production of the individual Parts, resulting in an integrated manufacturing and assembly process allows becomes.

One special smooth Surgical instrument leaves produce when the shaft, the sealing element and / or the at least one piston at least partially with a friction-reducing Coating are provided. Preferably, the friction-reducing Coating on at least one of two abutting and / or sliding along one another and / or sliding along one another Parts provided. The friction-reducing coating can in particular by subsequent Application of suitable coating materials are formed. However, a friction-reducing coating can be especially also by adding friction-reducing materials to one or more several basic materials that make up the coating too training parts are trained.

It is particularly efficient if an outer surface of the at least one piston, an inner surface of the shaft and / or outer and / or inner surface of the sealing element are provided with the friction-reducing coating. In particular, the surfaces mentioned can slide off each other or abut each other when the at least one piston is moved relative to the shaft. In particular, an efficiency of the arrangement comprising the at least one piston and the associated sealing element may be greater than 0.5, wherein the efficiency is defined as the ratio of actual piston force to theoretically achievable piston force. The better the parts are matched to one another, the higher the correspondingly achievable efficiency, which is preferably greater than 0.75 and can even reach values greater than 0.85.

Especially economical and easy to manufacture will be the instrument when the friction-reducing Coating polytetrafluoroethylene (PTFE) is or contains.

In order to the instrument in a simple way by curved and / or tortuous accesses to a Operation site in a body of a patient can be, it is advantageous if the shaft flexible and / or is elastic and / or bendable.

advantageously, the shaft is formed in the form of a tube. The hose In particular, it can be flexible and / or bendable. It is favorable if he is inelastic. That way he can be prevented due to an increase in pressure inflated in the fluid section and deteriorates an efficiency of power transmission by means of the power transmission member.

One particularly stable instrument form when the shaft is formed in the form of a tube is. In particular, the shaft of a plastic and / or be made of a metal. In particular, it is conceivable a Support fabric off to provide a metal surrounding, for example, a shaft or incorporated in these, for example in an outer wall.

A stability of the instrument continue to increase if an outer shaft at least partially surrounding the shaft is provided. Of course can the outside shaft also the shaft completely be formed surrounding. This is to be understood on the one hand that the outer shaft the shaft both in the longitudinal direction as well as circumferentially completely or partially surrounds. Especially it is beneficial to the outer shaft only in the region of the sealing element and the at least one piston and the end effector. It's special with an outside shaft possible, this part, in particular the distal end region of the instrument, through the outer shaft in the desired manner to stiffen. Furthermore, the outer shaft in this area as an abutment for serve the end effector. This is in principle also by a distal end of the shaft feasible.

advantageously, is the outer shaft inflexible or stiff. As a result, the at least a piston due to movement relative to the shaft at this and / or on the outer shaft support. Of the outer shaft can in particular about extend beyond a distal end of the shaft and thus this extend in the distal direction and form part of it. It is then in particular also conceivable that the at least one piston is guided directly in the outer shaft, which then forms part of the shaft. On an inflexible or stiff outer shaft In addition, part of the end effector may be supported or stored.

According to one another preferred embodiment The invention can be provided that the outer shaft has a proximal Part of the end effector in the circumferential direction with respect to the longitudinal axis surrounds. This is how the outer shaft can do at least partially a guide for the Form end effector, namely the proximal part. Furthermore, the proximal part of the end effector may be on the outer shaft support and / or held or stored, thereby causing a movement the defined at least one tool element in a simple and secure manner pretend.

Around the power transmission member by an operator in a simple manner parallel to the longitudinal axis to be able to move, is it cheap if an actuator at the proximal end of the instrument for moving the power transmission member is provided.

A Haptic of the instrument leaves improve in a simple way, in particular, that the actuator comprises at least one movable grip element. So an operator can capture the surgical instrument on the actuator and by moving the handle member, the power transmission member in the desired Move way to move the at least one tool element.

Especially simply the structure of the actuator, if the at least one gripping element can be pivoted about a pivot axis is stored. in principle would it be also conceivable to store the at least one handle element displaceable.

A power transmission from the at least one gripping element on the at least one piston particularly simple if the at least one handle element with the at least one piston is hingedly connected.

The instrument is particularly easy clean when the actuator is detachably connectable to the shaft and / or the power transmission member. Furthermore, this has the advantage that, for example, an actuating device can be provided which is reusable and cleanable and can be connected to disposable shafts and power transmission members, even with different end effectors.

The stability of the instrument can be increased in particular by the fact that the shaft relative to the actuator is arranged fixed. This allows in particular a mobile Storage of the power transmission member relative to the actuator. Furthermore, this simplifies the structure of the instrument.

The Handling the surgical instrument is simplified when the shaft and / or the power transmission member relative to the actuator around the longitudinal axis are rotatable. This allows an operator to make the instrument more comfortable for him Keep your posture and still have one at the distal end of the shaft of the Orient end effector in a desired manner, by twisting the shaft and / or the power transmission member relative to the actuator around the longitudinal axis.

Around one possible small compact design at least one distal end portion of the Instruments, it is favorable if the at least a tool element over at least one solid-state joint is stored at the end effector. Such end effectors are special low friction and can Moreover, they are practically free of play. In particular are Such end effectors also integrally formed and both made of a plastic as well as a metal. Furthermore, can be solid joints in particular be designed so that they simultaneously form a return element, around a deflected from a basic position tool element again back to the basic position to move after removing an actuating force. this means in particular, that such end effectors in particular also for reciprocating a tool element are suitable only by applying an actuating force in the form of a Push or a pulling force.

A Relative movement of the at least one tool element based on the shaft or a longitudinal axis of the same leaves can easily be achieved by the end effector comprises a fixed relative to the shaft portion which over the at least one solid-state joint is connected to the at least one tool element. So can At least a part of the end effector and / or the at least support a tool element on the shaft or stored on this be so a relative movement of the at least one tool element and the shaft by Be strike with an actuating force by means of the force transmission member to reach.

advantageously, The surgical instrument comprises two tool elements. These are preferably movably mounted relative to each other, but wherein a tool element optionally also relative to the shaft fixed can be trained.

According to one preferred embodiment of Invention may be a fluid supply be provided for feeding of the fluid under pressure into the fluid section. The fluid supply device allows in particular, to a piston for introducing an actuating force to dispense with or in the fluid section. For this can preferably serve directly the fluid supply, with which a fluid can be passed under pressure into the fluid section, around the at least one piston at a distal end of the instrument and over directly or indirectly to move the end effector.

Preferably is the fluid supply in Formed a fluid pump. This may in particular to a manually operated or an electrically operated Act fluid pump. This can go directly into a proximal end of the Instruments integrated or over a lead connected to a proximal end of the instrument be.

conveniently, is the actuator designed for pressing the fluid supply device. In particular, it may comprise at least one actuator to a Press fluid pump. This may in particular be a movable handle part, to exert a force on a manually operable fluid pump, or to an electrical or electromechanical or electronic component, with which an actuating signal for the operation of an electrically operated fluid pump can be generated is. The actuating device may also include a drive for the fluid pump. The control can also be on the fluid pump or separately from this be provided.

Cheap is if the at least one tool element is a tool end in Having a shape of a cutting edge or in the form of a jaw. So In particular, instruments in the form of scissors or tweezers or training forceps.

According to a preferred embodiment of the invention, the surgical instrument may be in the form of a pair of scissors, forceps or tweezers. With such instruments can perform a variety of surgical procedures.

The following description of preferred embodiments of the invention used in conjunction with the drawings for further explanation. Show it:

1 a partially broken perspective overall view of a surgical instrument;

2 : A perspective enlarged view of the area A from 1 ;

3 : an enlarged partial view of area B off 2 ;

4 : a view similar 3 an alternative embodiment of a surgical instrument;

5 : an enlarged view of an end effector of the 1 to 3 represented instruments;

6 a perspective, partially sectioned view of a distal end portion of another embodiment of an instrument;

7 a perspective view of an end effector of another embodiment of an instrument; and

8th : A perspective view of another embodiment of an end effector of a surgical instrument.

In 1 is a total with the reference numeral 10 provided surgical instrument comprising an elongated tubular shaft 12 , an end effector disposed at the distal end thereof 14 with two relative to each other about a pivot axis 16 pivotable tool elements 18 in the form of jaw-shaped jaw parts and one at the proximal end of the instrument 10 arranged actuator 20 for initiating and transmitting an actuating force to a generally numeral 22 provided with force transmission member for transmitting the actuating force to the end effector 14 for moving the tool elements 18 ,

The actuating device 20 includes a substantially transverse to one of the shaft 12 defined longitudinal axis 24 protruding handle 26 , on which a handle element 28 around one of the longitudinal axis 24 spaced but perpendicular to this pivot axis is pivotally mounted. A proximal end of the shaft 12 is in a distal direction from the handle part 26 projecting and coaxial with the longitudinal axis 24 arranged guide sleeve 32 held. The shaft 12 Can be fixed to the guide sleeve 32 or releasably connected to it.

In the proximal end region 34 of the shaft 12 is a first piston 36 parallel to the longitudinal axis 24 slidably mounted. It comprises a first piston section 38 , whose outer diameter to an inner diameter of the shaft 12 is adjusted. From the first piston section 38 is in the direction of the distal end facing a second piston section 40 coaxial to the longitudinal axis 24 from whose outer diameter is slightly smaller than the inner diameter of the shaft 12 so that the second piston section 40 surrounding annulus 42 is trained. One at the level of the longitudinal axis 24 trained and from the handle element 28 Distally facing pressure surface 44 is located on a pointing in the proximal direction end face of the piston 36 and can by pivoting the handle element 28 around the pivot axis 30 the piston 36 move in the distal direction. Thus, in particular, a hinged connection of the actuating device 20 and the piston 36 realized. Optionally, on the actuator 20 a non-illustrated restoring element may be provided which the handle element 28 transferred to a basic position when no pressure force is exerted on this, wherein in the normal position, the pressure surface 44 preferably occupies its most proximal position, which at the same time means that the furthest from the longitudinal axis 24 protruding operating range 46 of the handle element 28 protrudes maximally far in the distal direction and points in this.

The power transmission element 22 is designed in several parts and includes, inter alia, the piston 36 , Furthermore, the power transmission element comprises 22 another piston 48 , which is a distal end of the power transmission member 22 Are defined. The piston 48 is essentially identical to the piston 36 constructed and includes a first cylindrical piston portion 50 which has an outer diameter which corresponds to an inner diameter of the shaft 12 corresponds, so that the piston 48 essentially free of play in the shaft parallel to the longitudinal axis 24 is movably mounted. From a pointing in the proximal direction end face 52 of the first piston portion 50 is a second piston section 54 coaxial to the longitudinal axis 24 pointing in the proximal direction. The length of the second piston section 54 is about one third of the length of the first piston section 50 , The second piston section 54 surrounding is an annulus 56 educated. An end face pointing in the proximal direction 58 of the second piston portion 54 defines a printing area. Edges of the cylindrical second piston portion 54 are rounded.

Between the two pistons 36 and 48 a total extends with the reference numeral 60 provided fluid section. It includes an an inner wall 62 of the stem substantially between the second piston portions 40 and 54 lining hose 64 whose free proximal and distal ends 66 each with an identically formed sealing element 68 are closed. Below is therefore limited to the description of the coupling of the piston 36 and 48 to the fluid section 60 on the coupling of the piston 48 to the fluid section 60 , which define a so-called piston-seal element arrangement.

The hose 64 is preferably fixed to the shaft 12 connected and relative to this about the longitudinal axis 24 non-rotatable. He can even form a shaft when on the shaft 12 is waived. The sealing element 68 is directly to the hose 64 molded or firmly connected to this and connects directly to the respective end 66 at. The sealing element 68 includes a first, substantially sleeve-shaped portion 70 , which is almost twice as long as a length of the second piston portion 54 parallel to the longitudinal axis 24 , A free, from the end 66 wayward end of the section 70 is through a second section 74 of the sealing element 68 locked. The section 74 extends substantially transverse to the longitudinal axis 24 and defines a surface area that is substantially the size of an inner free cross-sectional area of the stem 12 equivalent. The sealing element 68 is flexible, but inelastic and formed overall in the form of a fluid-tight membrane, which forms a so-called rolling bellows. It has an annular edge facing away from the respective piston 76 on, in the present case, stuck with the end 66 of the hose 64 and thus indirectly fixed to the inner wall 62 connected is.

The hose 64 with the sealing elements formed on both sides 68 defines a fluid space 78 which is with a fluid 80 , preferably an incompressible liquid, is filled. The fluid space 78 is preferably filled gas-free, which means that in particular no air bubbles or gas bubbles in the fluid space 78 are included. In any case, this is the fluid 80 permanently in the fluid space 78 , which is preferably free of leakage, filled. A volume of the fluid 80 roughly corresponds to one of the hose 64 defined volume, that is the volume which is defined by the product of the inner cross-sectional area of the hose 64 and its length.

The second sections 74 the sealing elements 68 can optionally with the second piston sections 40 and 54 be connected, for example, with the face 58 of the second piston portion 54 , The sealing element 68 has a wall thickness that is less than 0.5 mm, preferably less than 0.1 mm, and depending on the choice of material may be less than 0.05 mm. The ratio between a length of the first section 70 and a diameter of the second section 74 is in the embodiment shown in the figures about 2. However, it may be less than 1, in particular less than 0.5 or 0.2.

The sealing element 68 is formed such that the second section 74 evertable is under education one from the edge 76 pointing away and in one of the edge 76 pointing away closed double-layered rolled sealing section 82 , This means that the first section 70 in the direction of the longitudinal axis 24 folded back on itself or turned over, leaving a first part of the first section 70 on the shaft 12 is a second part of the first section 70 on an outer surface of the second piston portion 54 , Overall, the sealing section emerges 82 in the annulus 56 without jamming. This allows the second section 74 parallel to itself in the direction of the longitudinal axis 24 is movable, both in the distal and in the proximal direction. During a movement of the second section 74 for example, in the distal direction, the partially turned first section rolls 70 and can be in a distal position of the piston 48 be completely unrolled and the inner wall 62 in the form of a cylindrical portion of the sealing element 68 line. Conversely, the second section 74 to the edge 76 be moved, the first section 70 then turned over so that the sealing portion 82 in about half the length of the first section 70 having. In principle, it is conceivable to choose the dimensions of the parts relative to one another such that the second section 74 in the proximal direction over the edge 76 towards the actuator 20 can be postponed. This is possible in principle until the first section 70 is completely unrolled again. This theoretically results in a maximum displacement of the piston 48 which is twice the length of the first section 70 equivalent.

The described arrangement of pistons 48 and sealing element 68 is analogous to the piston 36 intended. This is in 1 indicated schematically by dashed lines. The pistons 36 and 48 are preferably arranged so that in a basic position of the fluid portion 60 the second piston sections 40 and 54 at the second sections 74 abut, both at about the level of the edges 76 are arranged. The fluid space 78 is then, as described, bubble-free with the fluid 80 filled, which in particular also the annular space-like sections in the region of the sealing sections 82 fills.

Will the operating area 46 from the handle element 28 pivoted in the proximal direction, then the pressure surface 44 moves in the distal direction and pushes the piston 36 also in the distal direction. At the same time the second piston section 40 adjacent second section 74 of the sealing element 68 moved in the distal direction, and that on the distal side of the edge 76 , Due to the incompressibility of the fluid 80 is due to the movement of the piston 36 The piston 48 moved in the distal direction. The sealing section rolls 82 off, on the inside wall 62 of the shaft 12 fitting and supporting part of the sealing portion 82 is getting longer and the second piston section 54 fitting and supporting part of the sealing portion 82 gets shorter and shorter until the first section 70 is completely unrolled and the second section 74 a distal end of the sealing element 68 forms. In the opposite way leads a movement of the piston 48 in the proximal direction to a movement of the piston 36 also in the proximal direction. Are the sections 74 with the respective second piston sections 40 and 54 connected by a movement of the piston 36 in the proximal direction of the piston 48 also be pulled in the proximal direction.

The end effector 14 is at the instrument 10 directly on the piston 48 formed. Basically it would be possible to use the piston 48 and the end effector 14 with the tool elements 18 to train in one piece. The end effector will be easier to produce 14 in conjunction with the piston 48 however, when two identical parts are formed by means of a pivot axis 16 and a bearing shaft 84 defining pin are held on the shaft, which, for example, in coaxial with the pivot axis 16 oriented holes in a wall of the shaft 12 is stored. On the bearing shaft 84 are stored proximal end portions 86 of the tool elements that correspond with a bearing shaft 84 trained and arranged bore 88 are provided. The two end sections 86 the tool elements 18 are side by side on the bearing shaft 84 arranged.

With the respective end section 86 rigidly connected is a tool end 90 of the respective tool element 18 , In the present instrument 10 are tool elements 90 formed in the form of jaws that are about as wide as a diameter of the shaft 12 , Approximately in the middle between the distal end of the tool end 90 and the pivot axis 16 is through a gap 92 an outer surface of the tool element 18 defining, flat elongated bridge 94 formed, the proximal end of which is integral with the piston 48 is trained. The jetty 94 is flexible and elastically bendable and thus forms a linkage in the form of a solid-state joint 96 out. The production of both the piston 48 as well as the end effector 14 is simplified when two identical parts are formed. For this purpose, the piston 48 from two piston halves 98 composed of the longitudinal axis 24 defining connecting surfaces parallel to the webs 94 run and the piston 48 with its first and second piston sections 50 and 54 cut lengthwise in half. The piston halves 98 are firmly connected to each other, for example by gluing or welding.

The operation of the end effector 14 will be explained in more detail below.

In the 1 and 2 is the end effector 14 presented in a basic position. The tool ends 90 are slightly spread apart and define an opening angle between them 102 of about 30 °. The bridges 94 run in the normal position parallel to the longitudinal axis 24 , Will the piston 48 moving in the proximal direction, the webs become 94 also pulled in the proximal direction. Because the tool elements 90 rigidly pivotable about the bearing shaft 84 are stored, deforms the bridge 94 and thus the solid-state joint 96 so that the tool ends 90 from the longitudinal axis 24 be swung away to the outside. This allows the opening angle 102 enlarging what the grasping of tissue with the end effector 14 simplified. By ent speaking manufacturing, it is also possible in a basic position the web 94 to deform something, so without over the piston 48 initiated forces the respective tool elements 90 are pivoted further apart.

Will the piston 48 moving in the distal direction, also becomes the bridge 94 shifted in the distal direction. Because the tool ends 90 have no other possibility of movement than to be pivoted toward each other, this is done under appropriate deformation, that is, elastic deflection of the web 94 and thus the solid-state joint 96 , A displacement of the piston 48 is limited by the tool ends 90 whose inner surfaces in a closed position, which is not shown in the figures, abut each other or substantially abut each other.

The solid joints 96 allow a virtually backlash-free storage and power transmission from the power transmission element 22 on the tool elements 18 for moving the same, that is in the present case for pivoting about the pivot axis 16 ,

To move the piston 48 in the distal and proximal directions, as described above, the piston 36 be provided. Optionally you can on the piston 36 with associated Dichtungsele ment 68 also refrain if an alternative fluid supply device 104 , for example in the form of an external fluid pump, which via a supply line 106 with a proximal end of the shaft 12 of the tube arranged therein 64 is provided fluid-tight, is provided. With the fluid supply 104 can the fluid 80 in the proximal end of the shaft 12 pressed and thus the piston 48 be moved in the distal direction. Removing or reducing the pressure in the fluid 80 then leads due to the elastically resilient solid joints 96 to a Rückverschwenkung the tool elements 18 in its basic position and connected by the connection of the piston 48 over the footbridges 94 with the tool elements 18 , to a return movement of the piston 48 in the proximal direction.

An actuation of the fluid supply device 104 can for example via the pivotally mounted handle element 28 be realized, wherein preferably an electrical, electronic or electro-mechanical circuit element for actuating the fluid supply 104 due to a pivoting movement of the handle element 28 is provided, for example in the form of a switch, buttons or electronic switching element, such as an optical sensor or an inductive or capacitive proximity sensor, not shown, which on the actuating device 20 is arranged to detect a movement of the handle member 28 relative to the handle part 26 ,

In a slightly modified version of the instrument 10 Can be optional on the hose 64 be waived. The piston-seal element arrangement can then in particular as in 4 look like this. The edge 76 does not work, like in the 2 and 3 shown, seamlessly into the hose 64 over, but is directly with the inner wall 62 connected. All other parts of the piston-seal element arrangement are identical and therefore for the sake of clarity provided with the same reference numerals as in 3 , The fluid space 78 is directly bounded by the shaft 12 , distally through the sealing element 68 and optionally a sealing element 68 for closing the fluid space 78 at the proximal end of the shaft 12 , However, it can alternatively also on this latter sealing element 68 be waived if a fluid supply 104 as described above.

In the 6 to 8th Three alternative embodiments of end effectors are shown. For the sake of clarity are in 6 Parts of the instrument 10 identical to the elements of the instrument already described above 10 are formed, provided with the same reference numerals.

In 6 is an alternative variant of an end effector overall with the reference numeral 114 characterized. He is integral with the piston 48 formed and shaped in one piece. To the piston 48 closes a substantially U-shaped opening 160 at, the free ends pointing in the distal direction. The opening 160 is transverse to the longitudinal axis of the shaft 12 arranged. The U-shaped aperture defines two parallel slots 162 , which are closed on the distal side and on the one hand an outer bridge 194 , which is elastically resilient and a first solid state element 196 defined, as well as in each case an inner web 195 limit, in turn, from each other through a parallel to the slots 162 extending, but in the distal direction open slot 164 are separated. Proximalseitig is the slot 164 through a cuboid end section 186 limited. The slot 164 widens slightly in the distal direction and thus defines an opening angle 102 between inner surfaces of tool ends 190 the tool elements 118 ,

The bridges 194 and 195 extend approximately parallel to each other over the same length parallel to the longitudinal axis 24 , where the webs 195 a bit thinner than the bars 194 , In a transverse bore 188 the end portion transverse to the longitudinal axis 24 an unillustrated bearing pin is held, the free ends in corresponding, in 6 not shown holes on the shaft 12 intervene and so the end section 186 relative to the shaft 12 set in a defined manner.

Will the piston 48 moved in the distal direction, so are the webs 194 moved in the distal direction and the tool ends 190 the tool elements 118 pivoted towards each other until the surfaces of the tool ends 190 in extreme cases abut each other. Will the piston 48 released in the proximal direction, for example by removing or reducing the pressure in the fluid 80 , the solid joints can 196 the tool ends 190 , even under the effect of the bridges 195 defined solid joints 197 , again from the longitudinal axis 24 swing away to the outside. Will the piston 48 about the in 6 shown basic position retracted further in the proximal direction, this causes a further opening of the tool ends 190 , So an increase in the opening angle 102 , The bridges 194 and 195 then deform each slightly by elastic bending of the longitudinal axis 24 path.

Another variant of an end effector is in 7 total with the reference numeral 214 Mistake. He is under construction the end effector 114 very similar. It is essentially integral with the piston 48 educated. A substantially cuboid opening 260 transverse to the longitudinal axis 24 defined, similar to the opening 160 at the end effector 114 , two parallel webs 294 , which are solid-state joints 296 define. The bridges 294 are elastically resilient and connect the rigid tool ends 290 the tool elements 218 integral with the piston 48 , Coming from the distal, the slot extends 264 until the opening and opens this. To a pivoting movement of the tool ends 290 relative to the longitudinal axis 24 to allow, in the opening a plate-shaped holding part 268 symmetrically between the bars 294 used and on both sides in a manner not shown on the shaft 12 established. To guide a movement of the tool ends 290 serve two elastomeric body, on the one hand on the holding part 268 and on the other hand on inner surfaces of the webs 294 near the transition area to the respective tool end 290 are arranged. Towards the holding part 268 takes a thickness of the elastomeric body 270 from.

Will the piston 48 moved relative to the shaft in the distal direction, so are the webs at the same time 294 advanced in the distal direction. This leads to an elastic deformation of the elastomer body 270 so that this is the jetty 294 and thus the tool ends 290 in the direction of the longitudinal axis 24 to turn back. Will a pressure on the piston 48 reduced or completely removed, due to the deformation in the elastomeric bodies 270 and the jetties 294 stored energy, these the two parts back in their in 7 shown starting position back, so that the tool ends 290 reopen and its original opening angle 102 pretend again relative to each other. To increase the opening angle 102 can the piston 48 be further moved in the proximal direction, whereby due to the compound movement of the webs 294 the elastomeric body 270 pulls in the proximal direction and the tool ends 290 to a pivoting movement of the longitudinal axis 24 forcing away.

A modified variant of the end effector 214 is schematic in 8th shown. For clarity, only the modified parts of the end effector 214 provided with other reference numerals.

Instead of the two elastomeric bodies 270 is a single one-piece elastomeric body 280 between the two bridges 294 set and connects these. The elastomer body 280 is also firmly connected to an inner wall of the shaft. In the remaining opening 260 between the elastomeric body 280 and the piston 48 is another elastic body 282 used.

An operation of the end effector 214 with the elastomer body 280 and the elastic body 282 corresponds to a function of the end effector 214 with the holding part 268 and the elastomeric body 270 , The material of both the elastomeric body 270 as well as the elastomer body 280 may be formed, in particular a thermoplastic elastomer, silicone or other elastic plastic material. The provision of the elastic body 282 has the advantage that an unintentional blocking of the flexible connecting parts in the form of the webs 294 by unwanted intrusion of foreign bodies in the opening 260 is prevented. In addition, there is an economical mass production of such end effectors 214 readily possible.

In the instrument described above 10 can the end effector 14 be exchanged for any other end effector, in particular against the end effectors described above 114 and 214 ,

The fluid section 60 can be formed in the manner described by a one-sided or double-sided limited shaft portion, as a shaft, in particular, a flexible, flexible shaft would be conceivable, in particular in the form of a hose. One could therefore use the instrument 10 also on the shaft 12 completely dispense or provide only a short outer shaft portion, which is from the pivot axis 16 in the proximal direction until beyond the end 66 extends, as far as a length of the first section 70 parallel to the longitudinal axis. The outer shaft portion is then preferably rigid so that the end effector 14 with the bearing shaft 84 can be supported on it and held. By appropriate shaping or corresponding manufacturing method, the shaft and the outer shaft portion may also be integrally formed, as well as the one piece with the hose 64 formed sealing element 68 , The sealing elements 68 form flexible formations of one with the fluid 80 filled hollow body, which is formed by the shaft and / or the hose or a multi-layer hose. The shaft can be flexible in whole or in sections. By choosing the dimensions of the sealing element 68 is under the action of the fluid 80 with pressure the first section 70 against the hose 64 and the shaft 12 pressed. By appropriate choice of the dimensions also ensures that the sealing element 68 in a defined way in the annulus 42 rolls.

A twisting of the pistons 36 and 48 in the shaft 12 can be prevented by appropriate guides. For example, grooves may be provided in the shaft for this purpose, in the corresponding projections on the piston 36 and 48 intervention. Are the guide elements or guide members parallel to the longitudinal axis 24 arranged, the guide device simultaneously forms a rotation.

Overall, the sealing element is laterally through the surrounding inner wall 62 of the shaft 12 supported as well as by the face 58 of the second piston portion 54 , The only unsupported areas of the sealing element 68 are the bent areas that are in the annulus 42 or 56 dive in or towards the other end of the instrument 10 point. This high level of support, despite a very thin foil-like or membrane-like design of the sealing element 68 achieved a high pressure resistance of the transmission system as a whole.

The one or more sealing elements 68 as well as the shaft 12 and the hose 64 are made of materials that are biocompatible and resistant to the fluid 80 are. Preferably, the materials are easy to process, well to fit, inexpensive, durable, abrasion resistant and sterilizable. For the sealing elements 68 is a flexible, rather inelastic material with high abrasion resistance of advantage, since the sealing elements 68 made of elastic materials would tend to unwilling inflation and thus can easily burst. Particularly suitable are materials such as polyethylene, polypropylene or materials such as medical polyurethanes, polyethylene terephthalate (PET), polycarbonate (PC) or other plastics. Combinations of said materials, in particular multi-layered sealing elements can also be used to increase Barierreeigenschaften.

The shaft 12 and / or the hose 64 may also be made of a plurality of materials or composite materials, in particular of the materials mentioned. Both in the design of the sealing element 68 as well as the shaft 12 and the hose 64 Material associations can be used specifically to improve the properties of the overall system.

So are for the sealing element 68 Foil composites or coatings conceivable, for example, reduce the permeability or selectively influence.

For the pistons 36 and 48 as well as the inner wall 62 Material combinations are chosen which allow a precise, simple and cost-effective production, in particular polymers or metals for the formation of the shaft 12 , The materials are chosen so that only low friction losses during a relative movement of the pistons 36 and 48 and the shaft 12 caused. Frictional losses can also be reduced by suitable coatings of the parts sliding against each other. In particular, a coating which is or contains polytetrafluoroethylene is suitable here. Also conceivable are targeted structuring of the surfaces sliding against each other.

The choice of different diameter of the sealing element 68 in the area of the second section 74 and the second piston portion 54 has a direct effect on the behavior of the power transmission. So needed a sealing element 68 high wall thickness, which thus has a correspondingly high compressive strength, more space for unrolling, so that the diameter of the second piston portion 54 must be made correspondingly smaller in order to ensure safe deadlock-free unwinding. A smaller diameter of the second piston portion 54 However, it also has a reducing effect on the maximum achievable transmission efficiency, so that the exact design of the system preferably weighs between the individual properties.

A maximum piston stroke of the described piston-seal element arrangement is limited by a length of the sealing element 68 parallel to the longitudinal axis 24 , This maximum achievable length of the sealing element 68 depends mainly on the material used and the manufacturing process. The sealing element 68 is preferably always on the shaft 12 and / or hose 64 fixed to a closed hollow body for the fluid 80 to build. A compound of the sealing element 68 with the piston 36 respectively 48 is not mandatory.

To equalize the pressure between end areas of the pistons 36 and 48 is preferably an outer surface of the piston 36 respectively 48 , Preferably the first piston portion 50 respectively 38 provided with a corresponding surface structure, for example depressions in the form of trenches or furrows. These can also be on the inner wall 62 be provided. So can a pressure balance between end areas of the piston 36 respectively 48 be achieved in order to avoid compression of trapped gas. This further reduces a game of the instrument.

The sealing element 68 , the shaft 12 and / or the hose 64 as well as the other part of the instrument 10 can be made separately and then joined together. For the production of the sealing elements 68 thermoforming processes such as deep-drawing, hot-blowing, embossing, extrusion, injection molding and the like are conceivable. The hose 64 and the sealing element 68 or the sealing element 68 and the shaft 12 can, for example, by thermal welding, targeted heating, ultrasound Welding or laser beam welding are connected to each other or by joining techniques such as gluing, tapping, clamping. The advantage here is the use of the same material for the sealing element 68 as well as the hose 64 and / or the shaft 12 ,

Particularly cost-effective to manufacture, are the hose 64 and the sealing element 68 in a combined manufacturing process, for example a combined injection / blow molding process. This assembly steps can be omitted and the manufacturing cost of the instrument is further reduced. The other elements can be manufactured separately and then joined together.

In the described instrument 10 is preferably the end effector 14 or one of the other end effectors with the piston 48 , the so-called "slave piston" combined. Preferably, the parts are integrally formed. The operation of the end effectors is in all cases described such that a relative displacement of the piston 48 to one on the shaft 12 or on the hose 64 held part is allowed to pivot a movement of the tool elements 18 to reach. Although in the described embodiments, a closing of the respective end effector by a movement of the piston 48 caused in the distal direction. It would also be conceivable, however, as a result of a displacement of the piston 48 in the distal direction, the end effectors in such a way that the tool elements 18 be pivoted away from each other.

For large swivel movements and opening angle 102 To be able to effect the tool ends, it is also possible, the tool elements 18 to be kept open in a basic position beyond the positions described above and shown in the figures. This can be effected in particular by special manufacturing methods, the introduction of a bias into the respective end effector, additional biasing elements such as springs or the like, or solely by geometrical design of the end effectors. This allows reaching large opening angles 102 also by a hydraulic "one-way actuator", that is solely by a movement of the piston 48 due to correspondingly high pressure in the fluid 80 in the distal direction. As described, it is optionally also possible the piston 48 move hydraulically not only in the distal, but also in the proximal direction.

The union of end effector and piston 48 enables a low-backlash and low-friction construction of the instrument.

All Variants of instruments described above are suitable for training force-feedback Direction Disposable instruments for the minimally invasive surgery. As a fluid are convenient for all instruments incompressible fluids such as water, physiological saline solutions, oils and mixtures or emulsions, which are also preferably biocompatible.

The sealing elements 68 can also, as already mentioned, be coated, which minimizes friction losses on the one hand, and on the other hand stability and thus durability of the instrument 10 even with a variety of movement cycles of the piston 48 elevated.

The sealing elements 68 In addition, they can not only be designed as simple rolling bellows, but they can have additional, in particular smaller, structures, that is to say recesses or recesses, which serve to improve the properties of the system.

Optionally, the two piston-seal member assemblies at the proximal and distal ends of the instrument 10 a leak-free pressure relief valve may be provided to allow for possible deformation of the sealing elements 68 to avoid. Furthermore, in addition, a reservoir for the fluid 80 be provided to a permanently bubble-free filling of the fluid space 78 sure. Furthermore, a degassing device can also be provided in order to remove gases trapped in the fluid space therefrom and thus the fluid 80 bubble-free in the fluid space 78 to keep.

The piston-seal element arrangements described above make it possible to dispense with sealing rings and therefore in particular a very low-backlash power transmission. Consequently, it is also possible to achieve a high power transmission efficiency of more than 0.85 as well as power transmission even at very low driving pressures. The described sealing elements 68 allow a leak-free working and are much easier to design and manufacture than bellows. Manufacturing tolerances in the field of pistons 36 respectively 48 have virtually no effect on the power transmission, since the sealing elements 68 an optimal sealing of the fluid space 78 to ensure. Furthermore, power transmission losses in the described instruments are minimized by the fact that the sealing element 68 is not elastically deformed, as is the case with an elastic membrane. In connection with the storage of energy in energy stores, at least minimal losses are generally to be expected.

Claims (63)

Surgical instrument ( 10 ) with a shaft ( 12 . 24 ), at least one movably mounted tool element ( 18 ; 118 ; 218 ) end effector ( 14 ; 114 ; 214 ) and one in the shaft ( 12 . 24 ) in the distal and proximal direction movably mounted force transmission member ( 22 ) for transmitting one at a proximal end of the instrument ( 10 ) actuated force on the end effector ( 14 ; 114 ; 214 ) for moving the at least one tool element ( 18 ; 118 ; 218 ) from a first to a second tool element position and / or vice versa, wherein the force transmission member ( 22 ) at least one in the shaft ( 12 ) displaceably mounted pistons ( 36 . 48 ) and one of the at least one piston ( 36 . 48 ) by a sealing element ( 68 ) separate fluid section ( 60 ), which is filled with a fluid ( 80 ), which by pressurization against the sealing element ( 68 ) is depressible for moving the sealing element ( 68 ) adjacent at least one piston ( 36 . 48 ) parallel to the longitudinal axis ( 24 ) of the shaft ( 12 ), wherein the at least one piston ( 36 . 48 ) a first piston portion ( 38 . 50 ), which one to an inner diameter of the shaft ( 12 . 24 ) adapted outer diameter, characterized in that the at least one piston ( 36 . 48 ) a second piston portion ( 40 . 54 ), which of the first piston portion ( 38 . 50 ) in the direction of the fluid section ( 60 ) protruding and having an outer diameter which is smaller than an inner diameter of the shaft ( 12 . 24 ), and that the sealing element ( 68 ) is everted to form a double-layered rolled sealing portion. Surgical instrument according to claim 1, characterized in that the force transmission member ( 22 ) two pistons ( 36 . 48 ), which between them that of the piston ( 36 . 48 ) by a respective sealing element ( 68 ) separate fluid section ( 60 ) on the distal and proximal sides. Surgical instrument according to claim 1 or 2, characterized in that the fluid section ( 60 ) a fluid space ( 78 ), which is completely closed and sealed. Surgical instrument according to claim 3, characterized in that a sheath of the fluid space ( 78 ) by two sealing elements ( 68 ) and the shaft ( 12 . 24 ) is defined. Surgical instrument according to one of the preceding claims, characterized in that the at least one piston ( 48 ) directly or indirectly with the end effector ( 14 ; 114 ; 214 ) is coupled for moving the at least one tool element ( 18 ; 118 ; 218 ) due to movement of the at least one piston ( 48 ) in the proximal and / or distal direction. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) is flexible. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) is inelastic. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) in the form of a fluid-tight membrane ( 68 ) is trained. Surgical instrument according to claim 8, characterized in that the membrane ( 68 ) a bellow ( 68 ) or a rolling bellows ( 68 ). Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) a sleeve-shaped first section ( 70 ), which is closed on one side. Surgical instrument according to claim 10, characterized in that an outer diameter of the first section ( 70 ) an inner diameter of the shaft ( 12 . 24 ) corresponds or substantially corresponds. Surgical instrument according to claim 10 or 11, characterized in that the first section ( 70 ) by a transversely or substantially transversely to the longitudinal axis ( 24 ) of the shaft ( 12 . 24 ) extending second section ( 74 ) of the sealing element ( 68 ) is closed. Surgical instrument according to claim 12, characterized in that one of the second section ( 74 ) defined area substantially the size of an inner free cross-sectional area of the shaft ( 12 . 24 ) having. Surgical instrument according to claim 12 or 13, characterized in that the sealing element ( 68 ) is arranged and arranged such that the second section ( 74 ) parallel to itself in the direction of the longitudinal axis ( 24 ) is movable. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) at the schaff ( 12 . 24 ) is fixed fluid-tight. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) an annular Edge ( 76 ), which on the shaft ( 12 . 24 ). Surgical instrument according to claim 16, characterized in that the sealing element ( 68 ) is designed such that the first section ( 70 ) is evacuated to one of the edge ( 76 ) pointing away and in a from the edge ( 76 ) pointing away direction closed double-layered rolled sealing section ( 82 ). Surgical instrument according to one of claims 16 or 17, characterized in that the sealing element ( 68 ) is arranged and arranged such that the second section ( 74 ) on the proximal and distal sides of the rim ( 76 ) is movable. Surgical instrument according to one of Claims 16 to 18, characterized in that the edge ( 76 ) on an inner wall ( 62 ) of the shaft ( 12 . 24 ). Surgical instrument according to one of Claims 16 to 19, characterized in that the edge ( 76 ) on an outer wall of the shaft ( 12 . 24 ). Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) is made by a thermoforming process. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) is made by deep drawing, hot blowing, stamping, extrusion or injection molding. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) by thermal welding to the shaft ( 12 . 24 ) is fixed at this. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) by gluing or jamming with the shaft ( 12 . 24 ) is fixed at this. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ) and the shaft ( 12 . 24 ) are made of the same material. Surgical instrument according to one of the preceding claims, characterized in that the at least one piston ( 36 . 48 ) is rotationally symmetrical with respect to the longitudinal axis. Surgical instrument according to one of the preceding claims, characterized in that the first piston portion ( 50 ) directly or indirectly with the end effector ( 14 ; 114 ; 214 ) is coupled or integrally formed therewith. Surgical instrument according to one of the preceding claims, characterized in that the second piston portion ( 40 . 54 ) surrounding an annulus ( 42 . 56 ) is trained. Surgical instrument according to claim 28, characterized in that the annulus ( 52 . 56 ) is dimensioned such that the at least partially everted sealing element ( 68 ) in the annulus ( 52 . 56 ) can immerse without jamming. Surgical instrument according to claim 28 or 29, characterized in that the annular space ( 52 . 56 ) is dimensioned such that the double-ply rolled sealing portion ( 82 ) in the annulus ( 52 . 56 ) can immerse without jamming. Surgical instrument according to one of the preceding claims, characterized in that the second piston portion ( 40 . 54 ) parallel to the longitudinal axis ( 24 ) is about half as long as the first section ( 70 ) of the sealing element ( 68 ). Surgical instrument according to one of the preceding claims, characterized in that the at least one piston ( 36 . 48 ) is provided on an outer side with a surface structure such that a gas exchange between its two ends is made possible when the at least one piston ( 36 . 48 ) in the shaft ( 12 . 24 ) is arranged. Surgical instrument according to one of the preceding claims, characterized in that a shaft inner wall ( 62 ) is provided with a surface structure such that a gas exchange between both ends of the at least one piston ( 36 . 48 ) is made possible when the at least one piston ( 36 . 48 ) in the shaft ( 12 . 24 ) is arranged. Surgical instrument according to claim 32 or 33, characterized in that the surface structure comprises at least one recess, which fluidly connects between both ends of the at least one piston ( 36 . 48 ). Surgical instrument according to one of the preceding claims, characterized by guide means for guiding a movement movement of the at least one piston ( 36 . 48 ) in the shaft ( 12 . 24 ) parallel to the longitudinal axis ( 24 ). Surgical instrument according to claim 35, characterized in that the guide device forms an anti-rotation device for preventing a rotation of the at least one piston ( 36 . 48 ) in the shaft ( 12 . 24 ) about the longitudinal axis ( 24 ). Surgical instrument according to claim 35 or 36, characterized in that the guide means comprises first and second cooperating guide members, one of which on the at least one piston ( 36 . 48 ) and another on the shaft ( 12 . 24 ) is arranged, and that the first guide member in the form of a guide projection and the second guide member is formed in the form of a guide recess. Surgical instrument according to claim 37, characterized in that the guide recess in the form of a parallel to the longitudinal axis ( 24 ) extending guide groove is formed. Surgical instrument according to one of the preceding claims, characterized in that the sealing element ( 68 ), which has at least one piston ( 36 . 48 ) and / or the shaft ( 12 . 24 ) are made of one or more of polyethylene (PE), polyurethane (PU), polyethylene terephthalate (PET), polycarbonate (PC) and polypropylene (PP). Surgical instrument according to one of the preceding claims, characterized in that the shaft ( 12 . 24 ), the sealing element ( 68 ) and / or the at least one piston ( 36 . 48 ) are at least partially provided with a friction-reducing coating. Surgical instrument according to claim 40, characterized in that an outer surface of the at least one piston ( 36 . 48 ), an inner surface ( 62 ) of the shaft ( 12 . 24 ) and / or outer and / or inner surfaces of the sealing element ( 68 ) are provided with the friction-reducing coating. Surgical instrument according to claim 40 or 41, characterized in that the friction-reducing coating Polytetrafluoroethylene (PTFE) is or contains. Surgical instrument according to one of the preceding claims, characterized in that the shaft ( 12 . 24 ) is flexible and / or elastic and / or bendable. Surgical instrument according to one of the preceding claims, characterized in that the shaft ( 24 ) in the form of a hose ( 24 ) is trained. Surgical instrument according to one of claims 1 to 43, characterized in that the shaft ( 12 ) in the form of a tube ( 12 ) is trained. Surgical instrument according to one of the preceding claims, characterized by the shaft ( 24 ) at least partially surrounding outer shaft ( 12 ). Surgical instrument according to claim 46, characterized in that the outer shaft ( 12 ) is inflexible or stiff. Surgical instrument according to claim 46 or 47, characterized in that the outer shaft ( 12 ) a proximal part of the end effector ( 14 ; 114 ; 214 ) in the circumferential direction relative to the longitudinal axis ( 24 ) surrounds. Surgical instrument according to one of the preceding claims, characterized by an actuating device ( 20 ) at the proximal end of the instrument ( 10 ) for moving the power transmission member ( 22 ) parallel to the longitudinal axis. Surgical instrument according to claim 49, characterized in that the actuating device ( 20 ) at least one movable grip element ( 28 ). Surgical instrument according to claim 50, characterized in that the at least one gripping element ( 28 ) about a pivot axis ( 30 ) is pivotally mounted. Surgical instrument according to claim 50 or 51, characterized in that the at least one gripping element ( 28 ) with the at least one piston ( 36 ) is hinged. Surgical instrument according to one of Claims 49 to 52, characterized in that the actuating device ( 20 ) with the shaft ( 12 . 24 ) and / or the force transmission member ( 22 ) is releasably connectable. Surgical instrument according to one of claims 49 to 53, characterized in that the shaft ( 12 . 24 ) relative to the actuator ( 20 ) is fixed. Surgical instrument according to one of claims 49 to 54, characterized in that the shaft ( 12 . 24 ) and / or the force transmission member ( 22 ) relative to the actuator ( 20 ) about the longitudinal axis ( 24 ) are rotatable. Surgical instrument according to one of the vo according to the preceding claims, characterized in that the at least one tool element ( 18 ; 118 ; 218 ) via at least one solid-state joint ( 96 ; 196 ; 296 ) at the end effector ( 14 ; 114 ; 214 ) is stored. Surgical instrument according to claim 56, characterized in that the end effector ( 14 ; 114 ; 214 ) one relative to the shaft ( 12 . 24 ) fixed part ( 84 ; 268 ; 280 ), which via the at least one solid-state joint ( 96 . 196 . 296 ) with the at least one tool element ( 18 ; 118 ; 218 ) connected is. Surgical instrument according to one of the preceding claims, characterized by two tool elements ( 18 ; 118 ; 218 ). Surgical instrument according to one of the preceding claims, characterized in that a fluid supply device ( 104 ) is provided for supplying the fluid ( 80 ) under pressure into the fluid section ( 60 ). Surgical instrument according to claim 59, characterized in that the fluid supply device ( 104 ) in the form of a fluid pump ( 104 ) is trained. Surgical instrument according to claim 59 or 60, characterized in that the actuating device ( 20 ) is configured for actuating the fluid supply device ( 104 ). Surgical instrument according to one of the preceding claims, characterized in that the at least one tool element ( 18 ; 118 ; 218 ) a tool end ( 90 ; 190 ; 290 ) in the form of a cutting edge or in the form of a jaw. Surgical instrument according to one of the preceding claims, characterized in that the surgical instrument ( 10 ) is in the form of a pair of scissors, a forceps or tweezers.