Force-limiting handgrip, surgical instrument and modular instrument system

Description

[0001] The invention relates to a handle with adjustable force limitation, a surgical instrument equipped therewith and a modular instrument system.

[0002] Endoscopic medical or surgical instruments with tools consisting of two jaws are known from the prior art. These tools can open and close when actuated by a handle, enabling them to grasp, extract, or cut objects or tissue during endoscopic procedures, depending on the design of the jaws. To actuate a tool located at the distal end of an instrument shaft, a force transmission element, such as a pull rod, extends through the shaft to the handle located at the proximal end of the shaft. The handle has a coupling mechanism that transmits the actuation of the handle to the force transmission element, whose movements, via a tool mechanism, cause the jaws to open and close.The handle, analogous to a pair of scissors, can have two articulated handle parts, whereby an opening movement of the handle parts can be translated into an opening movement of the jaws. Depending on the design of the actuation mechanism and the tool mechanics, however, an opening movement of the handle parts can also be correlated with the closing movement of the jaws.

[0003] To protect the components of a surgical instrument, especially the tool and the tool mechanism, from overload, which can occur when the actuating force on the handle is further increased while the jaw parts are blocked, there are force limiting elements designed to absorb the actuating force applied to the handle in such a case.

[0004] Since the jaw position of instruments depends, among other things, on whether and how much volume is grasped with the jaws, a stop that limits the opening angle of the handles is usually not an effective way to protect the instrument. This is because the components only begin to stretch when the jaws can no longer move towards each other during the closing motion, and the applied force continues to increase. The stretching of the individual components is inherent to the design and, up to a certain limit, remains within the flexible range where no damage to the components or the instrument occurs. Above this flexible range, with greater stretching due to higher operating force, plastic deformation and thus permanent damage occur. Further stress leads to component failure and potentially even fracture.This load limit can vary for each component and must be taken into account during the design process.

[0005] A known prior art handle of an optical forceps for rigid bronchoscopy (e.g., item no. 10378CF) from Karl Storz SE & Co. KG, Tuttlingen, Germany, incorporates an overload protection feature: a section of the handle can reversibly or elastically bend if the user applies excessive force to the handle, for example, when the jaws are locked. This overload protection safeguards the instrument and its components, such as the tool itself or the force transmission mechanisms, from potential damage or destruction. The design of this elastically deformable section determines the maximum force that can be transmitted to the tool, which is not exceeded when the jaws are locked. In the prior art handle with scissor-like handle sections, the elastically deformable section is, for example, a lever section of the movable handle part.The elastic deformability of the handle part in the area of ​​the lever section is influenced by the length of the lever section, the choice of material and the material thickness.

[0006] From DE 40 10 775 A1 a medical forceps is known in which the movable handle part is divided into two parts to limit the actuating force, which are connected to each other by a bending spring element.

[0007] DE 94 03 248 U1 discloses a surgical instrument in which one or both handle parts for actuating clamping jaws or other jaw parts have a slot-like opening as an elastic damping element in order to transmit the actuating force flexibly in order to avoid excessive contact pressure of the clamping jaws.

[0008] From DE 10 2012 210 763 A1 a medical instrument is known whose movable handle leg has a flexible bending joint.

[0009] DE 10 2006 042 985 A1 also discloses a medical instrument with elastically deformable handle devices.

[0010] Utility model DE 94 03 248 U1 teaches a surgical instrument whose handle limbs have a damping element in the form of a slot-like opening.

[0011] The patent application EP 0 450 608A1 shows a surgical forceps whose pivoting handle part consists of two parts connected by a bending spring element.

[0012] From US 2017 / 0196620 A1, a surgical instrument is known with a device for limiting the closing force, which is realized via a torsion spring.

[0013] Patent US 3,325,897 A describes a safety scissor whose handle parts give way when a predetermined cutting resistance is exceeded.

[0014] A disadvantage, however, is that such an overload protection device is always fixed to a specific force limit value. A handle equipped with such an elastic section for force absorption can therefore only be used for specific instruments or a specific class of tools for which this force limit value applies. Consequently, such a handle is unsuitable, or only conditionally suitable, for a modular instrument system that, as a building block system, includes different handles, shanks, and tools, each with its own force limit value. A handle with an overload protection device fixed to a specific force limit value is unsuitable for instruments with tools whose load limit is lower, as damage to the tool or instrument may occur before the overload protection device activates.Such a handle is still suitable for instruments with tools whose load limit is higher: While damage to the tool or other components of the instrument cannot occur, the overload protection would prevent the user from operating the tool with increased force, even though the tool is designed for it.

[0015] In order to adapt an overload protection system to the different load limits of the tools and / or other instrument components in a modular system, several handles with differently designed elastically deformable sections would be required, whereby it is up to the user to select the handle with an elastically deformable section whose force limitation matches the selected tool / instrument.

[0016] Furthermore, with a handle that has an elastically deformable section as an overload protection device, it is not possible to deactivate the force limitation of the handle, which would be desirable in some cases, for example if the tool operated with it tolerates even higher forces, or to be able to apply a higher force than intended in the application depending on the situation despite possible damage to the tool / instrument.

[0017] Based on this prior art, the object of the present invention is to provide an improved handle for a medical or surgical instrument.

[0018] This problem is solved by a single movement with the features of claim 1.

[0019] The further task of providing an improved surgical instrument is solved by the medical instrument with the features of independent claim 8.

[0020] Furthermore, an improved modular instrument system with the features of independent claim 9 is disclosed.

[0021] Preferred embodiments of the devices are described in the respective dependent claims.

[0022] According to a first embodiment, a handle according to the invention for a surgical instrument comprises a first handle part with a rigid lever section and a second handle part with an elastically deformable lever section, wherein the second handle part is pivotably connected to the first handle part and the elastically deformable lever section is designed to limit an actuating force applied to the second handle part to a predetermined limit force by means of elastic deformation. According to the invention, a slide is arranged on the rigid lever section, which can be moved and positioned along the rigid lever section. The slide also has a support section that points in the direction of the elastically deformable lever section and provides a stop point for the elastically deformable lever section.

[0023] The positionability of the slide along the rigid lever section allows for a variable stop and adjustment of the force limitation. By moving the stop point, the force can be adjusted or the travel of the stroke limited. The handle is characterized by a simple design, which allows for cost-effective implementation. Furthermore, the handle can be reused thanks to easy reprocessing, as all components are readily accessible for cleaning and disinfection. The reversible, adjustable overload protection, achieved through the adaptable force limitation, allows the handle to be used in a modular instrument system to implement various overload levels. It is equally conceivable, however, to use the handle for a non-disassemblable surgical instrument and to utilize the adjustment mechanism for fine-tuning. This allows for the compensation of tolerances that occur during manufacturing and assembly.

[0024] In a further embodiment of a handle according to the invention, the rigid lever section has detent recesses distributed along its length. The carriage, which has a guide section for guiding the carriage along a track of the rigid lever section, accordingly has a detent strut that can engage with one of the detent recesses.

[0025] Furthermore, in a further embodiment, a handle according to the invention can have an adjustment mechanism designed to automatically move the slide along the rigid lever section and position it in a position corresponding to a force limitation predetermined for the tool, depending on a tool which can be coupled to the handle via a shaft and a force transmission element.

[0026] According to a further embodiment of the handle according to the invention, such an adjustment mechanism can include a recognition unit for determining a coding parameter that assigns the tool, when coupled to the handle via the shaft and the force transmission element, to the position of the slide that corresponds to the force limit predetermined for the tool. Preferably, the coding parameter that can be determined by the recognition unit can be a length of the force transmission element and / or an outer diameter of the shaft.

[0027] Furthermore, in another embodiment, a handle may include a device for detecting deformation of the elastically deformable lever section. Preferably, such a device may include at least one strain gauge and / or at least one electrical contact pair. For evaluating the deformation of the elastically deformable lever section and / or for outputting or displaying corresponding information, the device for detecting deformation of the elastically deformable lever section may also be connected to a device for evaluating the deformation of the elastically deformable lever section and / or a device for outputting or displaying information.

[0028] Another embodiment of the handle according to the invention relates to the fact that the handle has an engagement device which is designed to engage with the elastically deformable lever section in a deformed state, wherein the engagement device is preferably a detent device or locking device.

[0029] To further adapt the force transmission, a handle according to a further embodiment can have a coupling device which is designed to couple the force transmission element with the second handle part and has a spiral spring which provides a variable translation of a rotary or pivoting movement of the second handle part into a linearly increasing distance of the force transmission element.

[0030] According to a first embodiment, a surgical instrument according to the invention comprises a shaft, a handle according to the invention with adjustable force limitation at a proximal end of the shaft, and a tool at a distal end of the shaft, wherein the tool is connected to a force transmission element that extends through the shaft into the handle. The handle has a stationary first handle part and a movable second handle part, which is coupled to the force transmission element in order to move the distal tool when the movable second handle part is actuated.

[0031] A modular surgical instrument system, as a further object of the invention, comprises, according to a first embodiment, a plurality of shafts, a plurality of handles, and a plurality of tools, each connected to a force transmission element, wherein each shaft, each handle, and each tool connected to a force transmission element can be combined to form a surgical instrument. At least one of the handles of the modular surgical instrument system is a handle according to the invention with adjustable force limitation.

[0032] Further embodiments, as well as some of the advantages associated with these and other embodiments, will become clearer and more easily understood through the detailed description below with reference to the accompanying figures. Objects or parts thereof that are essentially the same or similar may be provided with the same reference numerals. The figures are merely a schematic representation of one embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. It will be advantageous for those skilled in the art to also consider the features individually and combine them into meaningful further combinations.

[0033] This shows: Fig. 1 a side view of a handle according to the invention with the slide in a first stop position, Fig. 2 a side view of a handle according to the invention with the slide in a second stop position, Fig. 3 a side view of a handle according to the invention with the slide in a middle stop position, Fig. 4 a side view of a handle according to the invention in an alternative embodiment with the slide in the first stop position, Fig. 5 a side view of a surgical instrument according to the invention with the handle made of Fig. 1 , Fig. 6 a schematic representation of the deflection curve a) with fixed support on one side and point load at the free end and b) a floating support with fixed support on one side, point load at the free end and floating support in between.

[0034] The present invention relates to a handle with overload protection and a surgical instrument equipped therewith. The present invention further relates to a modular surgical instrument system that advantageously incorporates such a handle and thus provides advantageous adaptability of the force limitation by means of the overload protection.

[0035] In Fig. 1 bis 3 Figure 1 shows a handle 1, which is located in a surgical instrument 10, as exemplified in Figure 10. Fig. 5 The surgical instrument 10 comprises, in addition to the handle 1, a shaft 11 defining an instrument longitudinal axis L, and a tool 12 connected to a pull rod as a force transmission element 13 (shown in dashed lines). The handle 1 is located at a proximal end of the shaft 11, and the tool 12 is located at a distal end of the shaft 11. The force transmission element 13 is axially movably mounted in the shaft 11 and extends to the handle 1. The handle 1 has a first handle part 3 that is fixed with respect to the instrument longitudinal axis L and includes a housing section 3.3 extending along the instrument longitudinal axis L. This housing section provides a receiving space for the proximal end section of the force transmission element 13 and an associated coupling device (not shown).A handle section movable relative to the first handle section 3, designated as the second handle section 2 of the handle 1, is connected to the force transmission element 13 via the coupling device, which is designed to translate a movement of the second handle section 2 into an axial movement of the force transmission element 13. The second handle section 2 is primarily formed by an elastically deformable lever section 2.1, which is pivotally connected to the first handle section 3 at a joint end 2.3 via a joint axis 5 as a pivot point, the joint axis 5 running transversely to the longitudinal axis L of the instrument through the housing section 3.3. The first handle section 3 has a rigid lever section 3.1, which is formed integrally with the housing section 3.3 and extends from the joint axis 5 at an angle to the longitudinal axis L of the instrument. This angle, which exists between the lever section 3.1 and the housing section 3.3 extending along the longitudinal axis L of the instrument is enclosed, in the example shown is approximately 100°, but can deviate from this and may, for example, also be in the range of 50° to 130°.

[0036] In the example shown, the lever ends 2.2, 3.2 of the elastically deformable and the rigid lever section 2.1, 3.1 are designed as handle loops, so that the elastically deformable and the rigid lever section 2.1, 3.1 with the lever ends 2.2, 3.2 resemble scissor handles.

[0037] To limit the force that can be applied via the handle 1 to the force transmission system, which comprises the coupling device, the force transmission element 13, and in particular the distal components tool mechanism and tool 12, the lever section 2.1 is designed to be elastically deformable. This means that, for example, if the tool 12 becomes jammed, the elastically deformable lever section 2.1 is subjected to elastic deformation when the actuating force exceeds the limit force specified for the respective force transmission system. The length, material, and cross-section of the elastically deformable lever section 2.1 determine the limit force at which the elastically deformable lever section 2.1 deforms and thus the force limitation becomes effective. This can be achieved by appropriately selecting the length, material, and cross-section of the elastically deformable lever section 2.1.1. The limiting force at which the elastic deformation of the elastically deformable lever section 2.1 begins can be set.

[0038] To further adjust the force limitation, the handle 1 has a slide 4 on the rigid lever section 3.1, which can be moved and positioned along the rigid lever section 3.1, thereby forming a variable stop point for the elastically deformable lever section 2.1. For this purpose, the slide 4 has a support section 4.2 that points in the direction of the elastically deformable lever section 2.1. In the illustrated example, the support section 4.2 is shaped like a hump to provide a defined stop point for the elastically deformable lever section 2.1.

[0039] Given the height of the support section 4.2, the angle between the elastically deformable lever section 2.1 and the rigid lever section 3.1, at which the elastically deformable lever section 2.1 abuts the stop point of the support section 4.2, is determined by the position of the slide 4 on the rigid lever section 3.1. From this stop point onward, the transmissible force is limited even without the tool 12 being blocked, since further force application to the first and second handle sections 2, 3 causes the elastically deformable lever section 2.1 to deform around the stop point. As long as the second handle section 2 is moved with larger opening angles between the elastically deformable lever section 2.1 and the rigid lever section 3.1, without the elastically deformable lever section 2.1 abutting the support section 4.2, force limitation by the elastically deformable lever section 2.1 only becomes effective when the tool 12 is blocked.

[0040] In Fig. 1 bis 3 The slide 4 is arranged in different positions along the rigid lever section 3.1 of the first handle part 3. As can be seen, the position of the slide 4 determines the stop angle of the handle 1. Fig. 1 The slide 4 is positioned in a first stop position near the joint axis 5 on the rigid lever section 3.1, causing the elastically deformable lever section 2.1 to strike the stop at a relatively large opening angle and the force limitation to become effective. Fig. 2 Figure 1 shows the slide 4 in a second stop position on the rigid lever section 3.1, which is furthest from the pivot axis 5, with the second handle part 2 abutting the support section 4.2 with the lever end 2.2, so that no force is absorbed by the elastically deformable lever section 2.1. Fig. 3 The slide 4 is arranged in a third stop position approximately in the middle on the rigid lever section 3.1, and the elastically deformable lever section 2.1 of the second handle part 2 is shown in a deformed state, which results from further force being applied to the second handle part 2 after it has stopped on the support section 4.2, until the lever ends 2.2, 3.2 meet.

[0041] The slide 4 can be fixed in its position, here via a fixed indexing system, whereby the rigid lever section 3.1 has indexing recesses 3.4 and the slide 4 has an indexing strut 4.3 that extends transversely through the guide section 4.1 and can engage in the indexing recesses 3.4. Alternatively to the example shown, modifications with a finer indexing system or with stepless positioning of the slide 4 are also possible; for this purpose, the slide 4 can, for example, have a locking device.

[0042] Furthermore, adjusting the force limitation via the stop makes it possible to counteract a higher torque at the force transmission element 13, which can be supported by a corresponding coupling to the force transmission element 13. For this purpose, in Fig. 4 A variant of the handle 1 is shown, which has an (Archimedean) spiral spring 6 as part of a (not shown) coupling device for coupling the force transmission element 13 with the second handle part 2, which provides a variable translation of the pivoting movement of the second handle part 2 into a linearly increasing distance of the force transmission element 13.

[0043] The purpose of overload protection or force limitation is to prevent damage to the sensitive components of a surgical instrument, which are usually the distal components, i.e., the tool and the tool mechanism. Damage can occur if the user operates the surgical instrument and the jaws become jammed during gripping / cutting, and further operation transmits excessive (hand) force to the force transmission system. This system extends from the handle, via a force transmission element such as a pull rod, to the distal instrument components: the tool mechanism and the tool itself. The overload protection is designed to absorb this overload force through the resulting (material) elongation, thus preventing instrument failure.

[0044] This can be illustrated by the similarity of the second handle part 2 to a single-sided clamped support T from the theory of technical mechanics, as in Fig. 6a und b is shown. The in Fig. 6a Deflection curve of a beam T (cantilever) of length shown l With fixed clamping at one end at point A and actuating force F at the free end (point C), this corresponds to the handle part with an elastically deformable lever section of a handle known from the prior art. The deflection curve of the support T in Fig. 6b In a floating bearing arrangement with a fixed bearing on one side at point A, actuating force F at the free end (point C), and with a sliding bearing at point B in between that is displaceable in the x-direction, this corresponds to the second handle part with an elastically deformable lever section of a handle 1 according to the invention. Point A corresponds to the joint axis 5 on which the joint end 2.3 of the second handle part 2 is arranged, and point C corresponds to the lever end 2.2, designed as a finger loop, on which a user applies the actuating force F. Point B illustrates the stop point, which is provided according to the invention by the adjustable slide 4. In a handle part from the prior art, the force limitation is set to a fixed actuating force F or a maximum deflection or deflection in the y-direction for a given force.If the deflection is limited to a maximum value by a stop, no further force can be introduced into the force transmission system from that point onward. For a deflection curve, as in . Fig. 6a As shown, the deflection / deflection in the y-direction results essentially from the length l , the material-dependent modulus of elasticity, i.e., the material of the elastically deformable lever section, as well as the cross-section-dependent area moment of inertia of the beam T.

[0045] A handle 1 according to the invention, which also has a second, movable handle part 2 with an elastically deformable lever section 2.1, allows, with the movable slide 4 as a variable support point, an adjustment possibility for influencing the force limitation range and also for deactivating the force limitation if necessary. The in Fig. 6b The depicted bending curve, which represents the bending of a handle according to the invention, illustrates the difference between the load case and the bending curve in Fig. 6a , which represents the bending line of a known handle.

[0046] In addition to the less relevant fixity at point A, which corresponds to the pivot axis 5, the beam T (movable handle 2 with elastically deformable lever section 2.1) is supported at another point B – the support section 4.2 of the slide 4 – thus influencing the deflection curve when loaded at point C (lever end 2.2). By making point B movable, the resulting deflection can change, creating an adjustable force limit. The displacement of point B is described by the distance a and can therefore theoretically take a value between 0 and the maximum beam length (sum of land a). Consequently, the limit is deactivated when point B is moved to the free end of the beam T, or when point B and point C are the same. Since the transmissible moment also changes with the lever length (the contact with point B corresponds to a pivot point), the tensile force at point A increases the closer point B is to point A. Therefore, it is important that the entire elastically deformable lever section is not too stiff. The bending behavior can be further influenced by changing the cross-section (partially or over the entire lever length). If the deflection at point C is large enough, handle 2 with its lever end 2.2 strikes a stop and is thus limited. In the example shown, this stop is provided by the lever end 3.2 of the first handle part 3, which is also designed as a finger loop (see figure). Fig. 3The longer the distance a, i.e., the distance in the x-direction between point B (slide 4) and point C (lever end 2.2), the lower the force F required to achieve the maximum deflection. With appropriate design, the user will experience a distinctly different resistance from the elastically deformable lever section 2.1 when moving the slide 4. A corresponding sensitivity can be achieved with reduced force.

[0047] The user can select the appropriate slide position for each tool, with markings (not shown) along the rigid lever section assisting in the correct selection. To prevent user error in choosing the slide position, it can be provided that the slide position is selected automatically, for example, via an adjustment mechanism (not shown) that reacts to a code of the inserted tool and then moves the slide to the corresponding position. This means that the adjustment mechanism is designed to automatically move the slide along the rigid lever section and position it in a position corresponding to a force limit predetermined for the tool, depending on the tool being coupled to the handle via a shank and a force transmission element.Such an adjustment mechanism can include a recognition unit that determines a coding parameter. This parameter allows the tool, when coupled to the handle via the shaft and the force transmission element, to be assigned to the corresponding position of the slide, which corresponds to the force limit predetermined for the tool. Suitable coding parameters could include, for example, the length of the force transmission element or the outer diameter of the shaft.

[0048] Further embodiments of the handles according to the invention, not shown, may relate to the realization of an additional function from the lifting movement of the elastically deformable lever section during bending. This can be a mechanical function or an electromechanical one. It is also conceivable to measure the resulting bending or load in the elastically deformable lever section. The handle may accordingly have a mechanical engagement device, such as a detent or locking device, designed to engage with the elastically deformable lever section in a deformed state.Alternatively or additionally, the handle may include an electromechanical device for detecting deformation of the elastically deformable lever section. This device may, for example, include a strain gauge and / or an electrical contact pair for triggering an electrical contact when the elastically deformable lever section is deformed. Such a device for detecting deformation of the elastically deformable lever section may be connected to a device for evaluating the deformation of the elastically deformable lever section and / or a device for outputting or displaying corresponding information.For example, an electrical contact can be closed by deformation of the leaf spring and a sensor can thus register an overload, or by using a strain gauge the bending of the elastically deformable lever section can be determined, which can be simultaneously displayed and / or evaluated electronically, for example.

[0049] The present invention provides a handle 1 for a surgical instrument 10, wherein the handle 1 comprises a first handle part 3 with a rigid lever section 3.1 and a second handle part 2 with an elastically deformable lever section 2.1. The second handle part 2 is pivotably connected to the first handle part 3, and the elastically deformable lever section 2.1 is configured to limit an actuating force applied to the second handle part 2 to a predetermined limit force by elastic deformation. A slide 4 is arranged on the rigid lever section 3.1, which is movable and positionable along the rigid lever section 3.1 and has a support section 4.2 that points in the direction of the elastically deformable lever section 2.1 and provides a stop point for the elastically deformable lever section 2.1.Furthermore, a surgical instrument 10, comprising a handle 1 with adjustable force limitation, and a modular surgical instrument system are disclosed. The drawings, the description, and the claims contain numerous features in combination. It is advantageous for a person skilled in the art to also consider the features individually and combine them into meaningful further combinations. REFERENCE MARK LIST

[0050] 1 Handle 2 First handle part 2.1 Elastically deformable lever section 2.2 Lever end 2.3 Articulated end 3 Second handle part 3.1 Rigid lever section 3.2 Lever end 3.3 Housing section 3.4 Detent recess 4 Slide 4.1 Guide section 4.2 Support section 4.3 Detent strut 5 Articulated axis 6 Coil spring 10 Surgical instrument 11 Shaft 12 Tool 13 Power transmission element Instrument longitudinal axis

Claims

1. A handle (1) for a surgical instrument (10), wherein the handle (1) has a first grip part (3) with a rigid lever section (3.1) and a second grip part (2) with an elastically deformable lever section (2.1), wherein the second grip part (2) is pivotably connected to the first grip part (3) and the elastically deformable lever section (2.1) is designed to delimit an actuating force applied to the second grip part (2) to a predetermined limit force by way of elastic deformation, characterised in that on the rigid lever section (3.1) is arranged a carriage (4) which can be moved and positioned along the rigid lever section (3.1) and has a support section (4.2), which points in the direction of the elastically deformable lever section (2.1) and provides a stop point for the elastically deformable lever section (2.1).

2. The handle (1) according to claim 1, characterised in that the rigid lever section (3.1) has latching recesses (3.4) and the carriage (4) has a guide section (4.1) which is designed to guide the carriage (4) along the rigid lever section (3.1) and has a latching strut (4.3) for engaging into the latching recesses (3.4).

3. The handle (1) according to claim 1 or 2, characterised in that the handle (1) has an adjusting mechanism which is designed to automatically move the carriage (4) along the rigid lever section (3.1) and to position it in a position which corresponds to a force limitation which is predetermined for the tool (12), depending on a tool (12) which can be coupled to the handle (1) via a shaft (11) and a force transmission element (13).

4. The handle (1) according to claim 3, characterised in that the adjusting mechanism has a detection unit for establishing a coding parameter which provides an assignment of the tool (12) when coupled to the handle (1) via the shaft (11) and the force transmission element (13) to the position of the carriage (4) which corresponds to the force limitation predetermined for the tool (12), wherein preferably the coding parameter, which can be established by the detection unit, is a length of the force transmission element (13) and / or an outer diameter of the shaft (11).

5. The handle (1) according to at least one of claims 1 to 4, characterised in that the handle (1) has a device for establishing a deformation of the elastically deformable lever section (2.1), which preferably has at least one strain gauge and / or at least one electrical contact pair, wherein the device for establishing a deformation of the elastically deformable lever section (2.1) is connected to a device for evaluating the deformation of the elastically deformable lever section (2.1) and / or a device for outputting or displaying an item of information.

6. The handle (1) according to at least one of claims 1 to 5, characterised in that the handle (1) has an engagement device which is designed to engage with the elastically deformable lever section (2.1) in a deformed state, wherein the engagement device is preferably a latching device or locking device.

7. The handle (1) according to at least one of claims 3 to 6, characterised in that the handle (1) has a coupling device which is designed to couple the force transmission element (13) to the second grip part (2) and has a spiral spring (6).

8. A surgical instrument (10) having a shaft (11), a handle (1) with a non-movable first grip part (3) and a movable second grip part (2) at a proximal end of the shaft (11), and a tool (12) at a distal end of the shaft (11), wherein the tool (12) is connected to a force transmission element (13) which extends through the shaft (11) into the handle (1) and is coupled to the movable second grip part (2), characterised in that the handle (1) is a handle (1) with adjustable force limitation according to at least one of claims 1 to 7.

9. A modular surgical instrument system having a plurality of shafts (11), a plurality of handles (1) and a plurality of tools (12) each of which is connected to a force transmission element (13), wherein each shaft (11), each handle (1) and each tool (12) connected to a force transmission element (13) can be combined to form a surgical instrument (10), characterised in that at least one handle (1) of the plurality of handles (1) is a handle (1) with adjustable force limitation according to at least one of claims 1 to 7.