Interspinous process spinal traction device

Abstract

An interspinous spinal traction device (1) is provided, which is designed to be placed between two spinous processes and defines a longitudinal axis (1a), a sagittal plane (1b) and a frontal plane (1c); the traction device (1) includes a base (2), which is designed to be placed between the two spinous processes and defines a first end and a second end; an anchoring unit (3), which is designed to expand and connect the traction device (1) between the two spinous processes; an actuator (5), which is designed to control the channel of the unit (3) between an expanded position and a contracted position; the base (2) has a sagittal portion with two opposing convex portions, thereby defining a profile with two concave portions (2a).

Description

Technical Field

[0001] The present invention relates to an interspinous vertebral traction device / interspinous vertebral traction apparatus / interspinous vertebral traction method of the type described in the preamble of the first claim.

[0002] In particular, the present invention relates to an implant designed to be implanted, preferably percutaneously, into the interspinous space to separate two adjacent vertebrae. Background Art

[0003] It is known that interspinous process traction can be surgically achieved by introducing an interspinous process spinal retractor between the two spinous processes, the retractor being controlled by an operator controlled device for inserting and controlling the retractor.

[0004] A distractor is a prosthesis designed to be implanted in the space between the spinous processes of two adjacent vertebrae in order to maintain intervertebral distraction suitable for limiting the loads transmitted between the vertebrae in cases of degenerative disc disease, thereby limiting the associated pain.

[0005] They mainly include a base body that can be arranged between the spinous processes and the expansion anchoring device of the retractor. The expansion of the anchoring device is controlled by a control device.

[0006] The interspinous spinal traction method involves positioning a traction device in the space between the spinous processes of two adjacent vertebrae. In detail, with the patient in a prone position, the affected intervertebral space is identified, the spinous processes are brought closer together by dilating the cannula, the size of the traction device to be inserted is determined by a probe, and finally, the selected traction device is inserted.

[0007] A first example of a surgical and traction device, in particular a traction device, is described in WO 2006102269. In this case, the traction device has a first pointed end to penetrate the intervertebral space formed by a first pair of open wings; the opposite end is provided with a second pair of fixed wings, which surround the column between the two pairs of wings.

[0008] Another example is described in document US8998955, in which there are two pairs of movable wings. One end of each wing is hinged to the base and the other end is free. In order to lock, the patent provides for rotating the wing at an angle greater than 120° so that the free end faces the spine.

[0009] Another example is described in WO2012069877, where locking and relatively easy introduction and removal are achieved by hook-shaped wings.

[0010] The described prior art includes some significant disadvantages.

[0011] In particular, despite the above solutions, the spinal traction methods / devices, and in particular the traction devices, are relatively complex and therefore particularly expensive. This is mainly due to the particular difficulties encountered by the operator in inserting and determining a stable position of the spinal traction device during the operation.

[0012] Another disadvantage is the low stability of the interspinous process spinal distractor once implanted.

[0013] An equally important disadvantage is that the control kinematics of the active wing are particularly complex.

[0014] Another disadvantage, therefore, is the cost and difficulty of implementing known interspinous process spinal distractors. Summary of the invention

[0015] In this case, the technical task of the present invention is to design an interspinous vertebral traction device / interspinous vertebral traction apparatus / interspinous vertebral traction method, which can substantially overcome at least some of the above-mentioned disadvantages.

[0016] Said technical task comprises the important object of the present invention, namely to have an interspinous vertebral distractor which is easy to insert and stable once implanted.

[0017] Another object is to provide an interspinous process vertebral distractor that is easy to implement and therefore less expensive.

[0018] The technical task and the specific aims are achieved by an interspinous vertebral traction device / interspinous vertebral traction apparatus / interspinous vertebral traction method as claimed in claim 1. Examples of preferred embodiments are described in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The features and advantages of the present invention are clarified by the following detailed description of preferred embodiments thereof with reference to the accompanying drawings, in which:

[0020] Figure 1 An interspinous vertebral distractor according to the present invention is shown in scale;

[0021] Figure 2a-2e The retractor in sequence in the interspinous process traction method according to the present invention is shown in scale;

[0022] Figure 3 Shown to scale Figure 1 Section of the middle tractor;

[0023] Figure 4 The components of the interspinous process traction device according to the present invention are shown in scale;

[0024] Figure 5 Shown to scale Figure 4 Components in

[0025] Figure 6a-6f A scaled representation of the preparation sequence of the interspinous process traction device according to the present invention; and

[0026] Figure 7 The interspinous process spinal traction method according to the present invention is illustrated. DETAILED DESCRIPTION

[0027] In this document, when used with terms such as "approximately" or other similar terms such as "substantially" or "substantially", measurements, values, shapes and geometrical references (such as perpendicularity and parallelism) are understood to exclude measurement errors or inaccuracies due to production and / or manufacturing errors, most importantly, except for slight deviations of the values, measurements, shapes or geometrical references related thereto. For example, if associated with a value, these terms preferably mean a deviation of no more than 10% of the value itself.

[0028] Furthermore, terms such as “first,” “second,” “higher,” “lower,” “primary,” and “secondary” when used do not necessarily indicate an order, relational priority, or relative position, but they may simply be used to more clearly distinguish different components from one another.

[0029] Unless otherwise specified, the measurements and data provided herein should be considered to be made under the International Civil Aviation Organization (ICAO) International Standard Atmosphere (ISO 2533). Referring to the drawings, reference numeral 1 generally designates an interspinous process vertebral distractor according to the present invention.

[0030] The traction device 1 is a percutaneous device that can be implanted for interspinous traction. The traction device is designed to be implanted in the interspinous space so that it is inserted between two adjacent vertebrae, thereby separating the two spinous processes.

[0031] The tractor 1 defines a longitudinal axis 1 a which is suitably a barycentric axis.

[0032] The distractor 1 defines a sagittal plane 1b, which is suitably centroidal; and / or a frontal plane 1c ( Figure 1 ), the frontal plane 1c is appropriately the center of gravity.

[0033] The sagittal plane 1b is perpendicular to the frontal plane 1c.

[0034] The intersection between the sagittal plane 1b and the frontal plane 1c defines the axis 1a.

[0035] The retractor 1 may include a base 2 designed to be placed between two spinous processes by spacing them apart.

[0036] The base body 2 defines a first end and a second end relative to the longitudinal axis 1 a.

[0037] The base body 2 may have a sagittal portion (ie, defined by the intersection of a sagittal plane 1 b and the base body 2 ) having at least one convex surface defining a recess 2 a for receiving a spinous process.

[0038] In detail, Figure 3 As shown, the sagittal portion has two convexities, so two recesses 2a are placed oppositely about the frontal plane 1c, and each recess is designed to accommodate a spinous process. The recesses 2a can be mirrored about the frontal plane 1c, so the sagittal portion is symmetrical relative to the frontal plane 1c.

[0039] The base body 2 may have a minimum sagittal height at the bottom of the at least one recess 2a, and preferably has a maximum sagittal height at the apex of the at least one recess 2a.

[0040] In this context, the expression "sagittal height" means the length measured perpendicular to the frontal plane 1c.

[0041] The minimum sagittal height of the base body 2 may be substantially less than 100%, more particularly less than 85%, more particularly less than 65%, of the maximum sagittal height of the same base body 2 .

[0042] The profile of the recess 2a may be elliptical, with a suitable eccentricity being less than 1, in particular less than 0.95, more particularly substantially between 0.95 and 0.75, preferably between 0.9 and 0.8.

[0043] The base 2 may have a frontal portion (i.e., defined by the intersection of the frontal plane 1c with the base 2) having a minimum cross-section near the first end. In detail, the frontal portion may include a first proximal portion at the first end of the minimum and appropriately constant frontal height; a second proximal portion at the second end of the maximum and appropriately constant frontal height; and a central portion connecting the first portion and the second portion, thereby defining at least one inclined surface 2b between the first portion and the second portion.

[0044] In this document, the expression "frontal height" means the length measured perpendicular to the sagittal plane 1b.

[0045] The central portion may have a monotonically increasing frontal height.

[0046] At least one inclined surface 2b is formed at the recess 2a.

[0047] The radial cross section of the base body 2 formed at the bottom of the depression 2a has a frontal height and a sagittal height substantially equal to each other. The radial cross section is preferably circular.

[0048] The starting point of the inclined surface 2b, ie, the central portion, is located at a shorter axial distance from the first end than the bottom of the recess 2a.

[0049] In this document, the terms "radial" and "axial" refer to directions / planes perpendicular and parallel to the longitudinal axis 1 a, respectively.

[0050] The maximum frontal height and the maximum sagittal height may be almost equal. The minimum frontal height may be less than the minimum sagittal height.

[0051] The central portion has two bevels 2b on opposite sides of the sagittal plane 1 b and suitably are almost mirror images of each other with respect to the sagittal plane 1 b. Thus, the central portion and thus the base body 2 may be mirror symmetrical with respect to the sagittal plane 1 b.

[0052] The base body 2 may be hollow.

[0053] The retractor 1 may comprise a unit 3 for locking the retractor 1 at the spinous processes, more precisely between the spinous processes.

[0054] The unit 3 is connected to the base 2 at a first end and can be moved relative to the base 2 so as to expand radially (in particular perpendicularly to the frontal plane 1 c ) to lock the retractor 1 between the spinous processes.

[0055] The unit 3 is designed to define at least one expanded position, in which it has a maximum radial expansion, and at least one contracted position, in which it has a minimum radial expansion.

[0056] The unit 3 defines the head of the retractor 1 which enters between the spinous processes.

[0057] The unit 3 may comprise at least one wing hinged to the base 2 at a first end defining an axis of rotation which is suitably nearly parallel to the frontal plane 1 c. In detail, it comprises a first wing 3 a hinged to the base 2 and a second wing 3 b hinged to the base 2 on the opposite side of the first wing 3 a relative to the frontal plane 1 c.

[0058] The wings 3a and 3b may have axes of rotation which are substantially parallel to each other. During a change of position of the unit 3, the wings 3a and 3b may rotate simultaneously and in opposite directions.

[0059] They may have a conical axial profile with a smallest cross section facing away from the basic body 2 , so that in the retracted position the locking unit 3 is axially conical, in particular pointed.

[0060] The wings 3a and 3b may have a U-shaped radial cross section with an opening facing the longitudinal axis 1 a.

[0061] The retractor 1 may comprise an additional unit 4 for locking the retractor 1 at the spinous processes, more precisely between the spinous processes.

[0062] The additional unit 4 is connected to the base body 2 at a second end and can be moved relative to the base body 2 to expand radially (in particular perpendicularly to the frontal plane 1 c ) to lock the retractor 1 between the spinous processes.

[0063] The additional unit 4 is designed to define an additional expanded position, in which it has a maximum radial expansion, and an additional retracted position, in which it has a minimum radial expansion.

[0064] The additional unit 4 may include at least one additional wing, which is hinged to the base 2 at the second end, and its rotation axis is appropriately almost parallel to the frontal plane 1c. In detail, it includes a first additional wing 4a hinged to the base 2 and a second additional wing 4b hinged to the base 2 on the opposite side of the first additional wing 4a relative to the frontal plane 1c.

[0065] The additional wings 4a and 4b have axes of rotation which are substantially parallel to each other, in particular to the wings 3a and 3b.

[0066] During a change of position of the additional unit 4, the additional wings 4a and 4b rotate simultaneously in opposite directions.

[0067] The tractor 1 may comprise an actuator 5 designed to control the transition of the tractor 1 between an anchored configuration and a non-anchored configuration. In the anchored configuration, the unit 3 is in an expanded position, locking the tractor 1 in the correct position; and, appropriately, the additional unit 4 is in an additional expanded position, locking the tractor 1 on the opposite side of the unit 3 relative to the recess 2a.

[0068] In the non-anchored configuration, the unit 3 is in a retracted position and does not lock the retractor 1 in the correct position; and suitably, the additional unit 4 is in an additional retracted position.

[0069] The actuator 5 is designed to rotate exclusively around the longitudinal axis 1 a relative to the base 2 by controlling a change in the configuration of the retractor 1 .

[0070] Figure 5 The actuator 5 shown may comprise a control thread 5 a of the unit 3 and, where appropriate, an additional control thread 5 b of the additional unit 4 .

[0071] The additional thread 5b may be opposite to the thread 5a.

[0072] To this end, the unit 3 may comprise, for each wing 3 a and / or 3 b , at least one thread 5 a engaging a tooth 3 c which, when pushed by the actuator 5 , controls the rotation of the wing 3 a and / or 3 b .

[0073] The additional unit 4 may comprise, for each additional wing 5a and / or 5b, at least one additional thread 5b engaging a tooth 4c, which, when pushed by the actuator 5, controls the rotation of the additional tooth 4c by controlling the rotation of the additional wing 4a and / or 4b.

[0074] The actuator 5 is externally controlled, and the base body 2 comprises an opening 2c for accessing the actuator 5 at a second end.

[0075] The opening 2c is always visible, ie accessible from the outside, regardless of the configuration of the retractor 1. Thus, the additional unit 4 in the retracted position is folded over the base body 2, leaving the opening 2c visible.

[0076] The actuator 5 is at least partially accommodated in the base body 2 .

[0077] The traction device 1 may be part of an interspinous process spinal traction device 10 .

[0078] The traction device 10 includes the aforementioned traction device 1 and a controller 20 for the traction device 1 .

[0079] like Figure 4 and 5 As shown, the controller 20 defines a main axis of extension 20a (preferably centroidal).

[0080] The controller is designed to engage with the retractor 1 at the opening 2c, suitably arranging the axes 1a and 20a substantially parallel to each other, more specifically such that they substantially coincide.

[0081] The controller 20 may include a first means 21 for controlling the rotation of the tractor 1 .

[0082] The first tool 21 is suitably designed specifically to define, together with the basic body 2 , a first rotational constraint, ie a constraint preventing them from rotating mutually about the axes 1 a and / or 20 a .

[0083] The first tool comprises first means 21a designed to engage with the body 2, suitably at the opening 2c, defining said first rotation constraint.

[0084] The first means 21a may comprise at least one tip, and the base 2 may comprise at least one seat 2d for inserting said tip. In particular, they comprise two tips located on opposite sides of the axis 1a, and the base 2 comprises a seat 2d for each tip.

[0085] The first tool 21 includes a hollow passage 21 b and thus defines a passage designed to communicate with the opening 2 c when the first tool 21 is attached to the base body 2 .

[0086] The channel 21a is parallel to the main extension axis 20a.

[0087] The first means 21b protrude from the channel 21b along the main extension axis 20a.

[0088] The first tool 21 may include a handle 21c connected to the channel 21b on an opposite side of the device 21a.

[0089] The controller 20 may comprise second means 22 for controlling changes in the configuration of the tractor 1 .

[0090] The second means 22 are suitably designed specifically to define, together with the actuator 5 , a second rotation constraint, ie a constraint preventing them from rotating mutually about the axes 1 a and / or 20 a .

[0091] It comprises second means 22a designed to engage with the actuator 5, appropriately at the opening 2c, defining the second rotation constraint

[0092] The second constraint is essentially an interlocking mechanism. For example, the actuator 5 may comprise a polygonal (for example hexagonal) end which is in view of the opening 2c, and the second means 22a may define a complementary shaped engagement seat at said end.

[0093] The second tool 22 can rotate relative to the base body 2 and the first tool 21 about the extension axis 20 a .

[0094] It can be inserted into channel 21a.

[0095] The second tool 22 may include an additional hollow passage 22 b and define an additional passage designed to communicate with the opening 2 c when the second tool 22 is attached to the actuator 5 .

[0096] The additional channel 22a is parallel to the main extension axis 20a.

[0097] The second tool 22 may include a head 22 c for controlling the second tool 22 .

[0098] The head 22c is designed to be placed outside the first tool 21 when the second tool 22 is in the channel 21b.

[0099] The controller 20 may include a third means 23 for axially constraining at least one of the tools 21 and 22 to the retractor 1 .

[0100] The third tool 23 is designed to engage with the actuator 5 by defining said axial constraint and thus prevents axial movement of the first tool 21 and / or the second tool 22 relative to the tractor 1 .

[0101] It may comprise third means 23a defining said axial constraint.

[0102] The third tool 23 may include a clamping element 23 b for controlling the third tool 23 .

[0103] The clamping element 23 b is designed to be placed outside the first tool 21 and the second tool 22 when the third tool 23 is in the additional channel 22 b .

[0104] The third means 23 a may define a threaded coupling with the actuator 5 .

[0105] The third tool 23 can be arranged at least partially in the additional channel.

[0106] The operation of the traction device 1 and the traction apparatus 10 described above in structural terms defines an innovative interspinous vertebral traction method 100, which is Figure 7 Indicated in the middle.

[0107] The method 100 includes a traction device 1 , in particular a traction device 10 .

[0108] The method 100 may include a preparatory step 110 in which the controller 20 is connected to the tractor 1 .

[0109] The preparation step 110 may include a first constraint sub-step 111 ( Figure 6a-6b ), wherein a first tool 21 is engaged to the base body 2, defining said first rotational constraint. In detail, by inserting at least one tip into at least one seat 2b, a first constraint is achieved thanks to the first means 21a.

[0110] The preparation step 110 may include a second constraint sub-step 112 ( Figure 6c-6d ), wherein the second tool 22 is engaged with the actuator 5 defining the second rotation constraint. In detail, the first constraint is achieved by coupling the second device 22a to the actuator 5 through interference.

[0111] In sub-step 112, the second tool 22 is inserted into the channel 21b.

[0112] The preparation step 110 may include a third constraint sub-step 113 ( Figure 6d-6e ), wherein the third tool 23 is designed to engage the actuator 5 defining said axial constraint.

[0113] At the end of the preparation step 110 , the retractor 1 is in the non-anchored configuration.

[0114] Method 100 may include a positioning step 120 ( Figure 2a-2b ), wherein the retractor 1 appropriately controlled by the controller 20, in particular by the first tool 21, is brought to the vicinity of the spinous process.

[0115] In this step 120, the retractor 1 is placed so that the frontal plane 1c is substantially perpendicular to the frontal plane of the patient and then moved along the longitudinal axis 1a, bringing the locking unit 3 substantially to the two spinous processes. The retractor 1 is then moved axially forward so that the unit 3 in the retracted position penetrates between the spinous processes and, due to its tapered profile, the unit 3 is arranged between the spinous processes.

[0116] When at least one bevel 2b approaches the spinous process, step 120 ends.

[0117] Method 100 may include inserting step 130 ( Figure 2b-2c ), wherein the base body 2, specifically the entire retractor 1, is rotated about the longitudinal axis 1a so that the frontal plane 1c is substantially parallel to the frontal plane of the patient, so that the two spinous processes are in the recess 2a.

[0118] In this step 130 , the first tool 21 rotates the tractor 1 and, more precisely, moves the tractor 1 axially and, preferably, simultaneously rotates the tractor 1 about the longitudinal axis 1 a .

[0119] The axial translation causes the spinous processes to slide along the bevel 2b, so that they gradually adapt to the contour of the sagittal portion and therefore to the at least one recess 2a.

[0120] This rotation enables the depression 2a to appear and thus properly accommodate the spinous process inside after the spinous process has traveled at least a portion of the bevel 2b. During the insertion step 130, the retractor 1 is rotated by an angle that is substantially between 60° and 120°, in particular between 75° and 105°, and preferably around 90°. The method 100 may include an expansion step 140 ( Figure 2c-2d ), wherein the tractor 1 switches from an anchored configuration to a non-anchored configuration.

[0121] In an expansion step 140 , the actuator 5 controlled by the second tool 22 brings the unit 3 into the expanded position, thereby constraining the retractor 1 between the spinous processes.

[0122] At the same time, the actuator 5 suitably controls the additional unit 4 to enter the additional expanded position, thereby constraining the retractor 1 between the spinous processes on the opposite sides of the unit 3 relative to the recess 2a.

[0123] It should be noted that the change in the configuration of the tractor 1 is controlled by rotating the second tool 22 relative to the first tool 21 , the first tool 21 suitably being kept substantially stationary.

[0124] Method 100 may include removing step 150 ( Figure 2e ) is used to move the controller 20 away from the tractor 1.

[0125] In this step 150 , the third tool 23 is disengaged from the actuator 5 ; the second tool 23 and the first tool 21 are then moved away from the tractor 1 .

[0126] The traction device 1 , the spinal traction apparatus 10 and the interspinous spinal traction method 100 according to the invention achieve important advantages.

[0127] Indeed, due to the particular configuration of the retractors 1 and / or the availability of the retractor controls defined by the controller 20, they are particularly simple and quick to use and in particular enable precise, secure and rapid positioning of the retractors 1 between the spinous processes.

[0128] An important advantage is therefore that, once implanted, the retractor 1 has a high stability. In fact, the retractor 1 has a precise housing for each spinous process, for example, thanks to the recesses 2a.

[0129] These advantages are enhanced by the presence of the bevel 2b which, by gradually spacing the spinous processes apart, enables a quick and precise positioning of the retractor 1 and a less invasive procedure for the patient.

[0130] Another important advantage is the special controller 20 which enables precise and practical control of the tractor 1 and in particular of the wings 3a and 3b and, where appropriate, of the additional wings 4a and 4b.

[0131] One significant advantage is that the distractor 1 (and therefore the spinal distraction device 10 and method 100) is low cost.

[0132] Modifications may be made to the invention, these modifications falling within the scope of the inventive concept defined in the claims. All details may be replaced with equivalent elements and the scope of the invention encompasses all other materials, shapes and dimensions.

Claims

1. An interspinous spinal traction device (1) designed to be placed between two spinous processes and defining a longitudinal axis (1a), a sagittal plane (1b) and a frontal plane (1c); the traction device (1) comprising - a base (2) designed to be placed between said two spinous processes and defining a first end and a second end relative to said longitudinal axis (1a); - an anchoring unit (3) firmly attached to said base body (2) at said first end and designed to expand perpendicularly to said frontal plane (1c); - an actuator (5) designed to control the passage of the anchoring unit (3) between an extended position, in which the anchoring unit (3) constrains the retractor (1) between the two spinous processes, and a retracted position, in which the anchoring unit (3) does not constrain the retractor (1) between the two spinous processes; And it is characterized by - said base (2) has a sagittal section with two opposite convexities to define a profile with two recesses (2a) situated on opposite sides of said frontal plane (1c), each recess being designed to accommodate one of said two spinous processes; The base (2) has a tapered front portion, and the smallest cross section of the front portion is located at the first end; The front part of the base (2) comprises a first part, a second part and a central part; the first part is located at the first end and has a minimum height, the second part is located at the second end and has a maximum height; the central part defines two inclined surfaces (2b) connecting the first part and the second part is located on the opposite side of the sagittal plane (1b).

2. The tractor (1) according to claim 1, wherein: The recess (2a) is formed on at least one inclined surface (2b).

3. The tractor (1) according to claim 1, wherein: The axial distance between the starting point of the inclined surface (2b) and the first end is shorter than the axial distance between the bottom of the recess (2a) and the first end.

4. The tractor (1) according to claim 2, wherein: The radial cross section of the base body (2) formed at the bottom of the recess (2a) has a frontal height and a sagittal height that are equal to each other.

5. The tractor (1) according to claim 1, characterized in that: The sagittal height of the base (2) at the bottom of the recess (2a) is less than 85% of the sagittal height of the base (2) at the apex of the recess (2a).

6. An interspinous process traction device (10), comprising: - an interspinous vertebral retractor (1) defining a longitudinal axis (1a); and - a controller (20) for the tractor (1); - The tractor (1) comprises A base (2) designed to be placed between two spinous processes and defining a first end and a second end relative to the longitudinal axis (1a); An anchoring unit (3) connected to the base (2) at the first end and designed to expand and restrict the retractor (1) at the two spinous processes; an actuator (5) for controlling the passage of the anchoring unit (3) between an expanded position, in which the anchoring unit (3) restricts the retractor (1) between the two spinous processes, and a retracted position, in which the anchoring unit (3) does not restrict the retractor (1) between the two spinous processes; Features - the base (2) comprises an opening (2c) for access to the actuator (5) at the second end; And the controller (20) includes - a first tool (21), comprising a hollow channel (21b), the first tool (21) being designed to rotatably attach itself to the base (2) at the second end by arranging the hollow channel (21b) to communicate with the opening (2c), thereby controlling the rotation of the retractor (1) relative to the spinous process; - a second means (22) designed to control the variation of said anchored unit (3) by means of said actuator (5); And among them - said second tool (22) is designed to be inserted into said hollow channel (21b) and to rotate relative to said first tool (21) of the unit (3) controlling said anchoring; - The traction device (1) defines a sagittal plane (1b) and a frontal plane (1c); wherein the front part of the base (2) includes a first part, a second part and a central part; wherein the first part is located at the first end and has a minimum height, wherein the second part is located at the second end and has a maximum height; wherein the central part defines at least one inclined surface (2b) connecting the first part and the second part; and wherein the base (2) has a sagittal cross-section, the sagittal cross-section includes at least one convex portion, and the convex portion defines at least one recess (2a) formed at the at least one inclined surface (2b).

7. The traction device (10) according to claim 6, wherein: The first tool (21) is designed to attach itself rotationally only to the base body (2); and wherein the second tool (22) is designed to attach itself rotationally exclusively to the actuator (5).

8. The traction device (10) according to claim 6, wherein: The controller (20) comprises a third tool (23) designed to axially connect the first tool (21) and the second tool (22) to the tractor (1); wherein the second tool (22) comprises an additional hollow channel designed to accommodate the third tool (23); wherein the third tool (23) is designed to be attached to the actuator (5).

9. The traction device (10) according to claim 6, wherein the first tool (21) comprises at least one tip; and wherein the base body (2) comprises at least one seat (2d) for inserting the tip.

10. The traction device (10) according to claim 6, wherein: The second tool (22) comprises a head (22c) of the second tool (22), and the head is designed to be located outside the first tool (21) when the second tool (22) is located in the hollow channel (21b).

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