Rod bending robot

Abstract

The disclosed rod bending device (1) is intended for bending a rod (3) according to an anatomy of a patient, said rod intended for stabilizing a spine of the patient. The rod bending device comprises a chuck (2), configured to receive and temporarily hold a first end (31) of the rod to be bent according to the anatomy of the patient, said chuck being arranged rotatably about a first axis (Y) driven by an electric rotation motor (4). The rod bending device comprises an electric linear displacement motor (5) configured to displace the chuck relative to a bending head (7) in the direction of the first axis. The rod bending device comprises said bending head comprising a first abutment (71) and a thereto relatively moveable second abutment (72) driven by an electric bending motor (6) to bend the rod around a bending edge (74) arranged at the first abutment.

Description

[0001] ROD BENDING ROBOT

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to a rod bending device, a system and a method for bending a rod, as well as a computer program product, in particular a method for bending a rod according to an anatomy of a patient.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] US11453041 B2 was first published in September 2022 on behalf of NuVasive. It is directed to a method for determining the shape of a surgical linking device that is to be attached to a bony body structure such as the spinal column based on digitized locations of a plurality of attachment elements engaged to the bony structure. The method is implemented by a computer system through a GUI to generate an initial bend curve to mate with the plurality of attachment elements. The initial bend curve may be simplified based on user input to the GUI to reduce the number of bends necessary to produce a wellfitting linking device and may be altered to help obtain the goals of surgery. This procedure is quite inaccurate and prone to errors, as a manually operated bending bench is used to bend the reinforcing rod pre- or intraoperatively manually. For each bending, the axial position of the rod in the bending bench needs to be adjusted to guarantee bending at the desired location. In addition, the reinforcing rod must be rotated axially before bending to allow 3D bends since the bending bench always applies the bending deformation in the same direction. Eventually, the bending is executed by pressing down a lever of the bending bench until it reaches a stop. The resolution of the system only has a coarse resolution. US2023245589A1 was first published in August 2023 on behalf of 25Segments. It describes a computer implemented method of assisting bending of a reinforcing rod. The method includes the steps of receiving spatial positions of chirurgical implants, in particular pedicle screws, captured by a camera-based positioning device, the chirurgical implants configured to attach to the reinforcing rod. Calculating a rod shape corresponding to the spatial positions, allowing the chirurgical implants to be attached to the reinforcing rod. Based on the calculated rod shape, calculating a sequence of bending parameter sets. Generating tool operation guidance for bending tools based on the bending parameter sets, the tool operation guidance indicating a sequence of prescribed operation steps. The sequence of prescribed operation steps are determined such, that when carried out using the bending tools, causes the bending tools to shape the reinforcing rod corresponding to the calculated rod shape.

[0006] W023170505A1 was first published in September 2023 on behalf of Medacta. It describes a method for calculating the shape of a rod of a pedicle screw system. The method comprises acquiring at least one bidimensional image of a spine; acquiring a tridimensional image of a spine; obtaining a tridimensional model of the spine; performing a sagittal balance analysis to calculate spinopelvic parameters and comparing them with predetermined values; applying corrections to the tridimensional model; calculating corrected spinopelvic parameters on the tridimensional model of the spine corrected and checking if they are within the predetermined range values. In negative case, repeating the steps. In a positive case, obtaining a tridimensional corrected model of the spine based on such tridimensional simulated corrections including a plurality of virtual screw; calculating the shape of the rod as mathematical function which approximates the curve passing through the virtual screw.

[0007] US2019133666A1 was first published in May 2019 on behalf of Globus Medical Inc. The document describes a robotic system which includes a robot base and a rod feeding subassembly coupled to the robot base that includes a feeding actuator configured to selectively move a surgical rod in steps by holding it in an intermediate position. The robotic system may include a brake subassembly coupled to the robot base that includes a brake actuator configured to receive the surgical rod from the rod feeding subassembly, and selectively fix a first portion of the surgical rod with respect to the brake subassembly. The robotic system may include a bending subassembly coupled to the robot base that includes a bending actuator configured to selectively rotate to engage a second portion of the surgical rod and bend the second portion of the surgical rod with respect to the first portion of the surgical rod so that the first portion and the second portion of the surgical rod define a first bend angle.

[0008] WO1 6088130A1 was first published in June 2016 on behalf of Mazor Robotics Ltd. The document is directed to a system for rod bending for use in robotic spinal surgery, enabling the correct bending of a fusion rod to match the shape required to pass through the heads of the pedicle screws. The system uses data generated by information provided to the robot by the surgeon's preoperative plan, optionally augmented by feedback from the robot control system of deviations encountered intraoperatively. Such deviations could occur, for example, when the surgeon decides intraoperatively on a different trajectory or even to skip screws on one vertebra, in which case, the robot will be commanded to perform the alternative procedure, with commensurate instructions relayed to the control system of the rod-bending machine. The system is also able to thin down the rod at predetermined locations along its length, adapted to be at selected intervertebral locations, for maintaining limited flexibility between vertebrae, instead of fixating them.

[0009] US2018289408A1 was first published in October 2018 on behalf of Warsaw Orthopedic. The document is directed to an implant bending device that includes a first work surface. An implant support is movable relative to the first work surface. A second work surface is movable relative to the first work surface. A sensor is connected with the work surfaces and configured to detect contact of at least one of the work surfaces with an implant. The presented device has a rather complicated design with gears arranged at 90° which tend to cause a lot of play in the transmission chain of the movement which might be a source of inaccuracy.

[0010] SUMMARY OF THE DISCLOSURE

[0011] Spinal fusion surgery is indicated for a variety of spinal disorders including deformity, trauma, degenerative disc disease, scoliosis, and spondylolisthesis. In the course of the surgery, pedicle screw implants are bilaterally inserted into the pedicles of pathological vertebrae and fused using a reinforcing rod to form a rigid connection. With a complication rate of up to 15%, the surgical treatment of the spine remains very challenging because the surgeon has to operate close to vital anatomical structures such as the spinal cord, nerve roots, and arteries. Due to the high risk of injury, spine surgery was one of the first surgical disciplines leveraging surgical navigation to enable more accurate and safer surgical execution. Pedicle screw placement is a frequently navigated surgical step in spinal surgery, whereas navigation of the rod bending process remains an almost unexplored field. Conventionally, computer assisted navigation of pedicle screw placement relies on externally tracked markers in combination with medical imaging techniques such as Computed Tomography (CT) or fluoroscopy to match a preoperatively generated intervention plan to the intraoperative anatomy. After a successful registration, the plan can be navigated by providing computer assistance as desired screw entry points and drilling trajectories to the surgeon.

[0012] After the chirurgical implants, in particular pedicle screws, have been implanted into the vertebrae, a reinforcing rod has to be adapted to the patient’s anatomy, respectively the position of the pedicle screws, so that it can be attached to the pedicle screws, in particular such as to fit into typically U-shaped openings of the pedicle screw heads. In a first aspect of the disclosure a rod bending device for bending a rod according to an anatomy of a patient is presented which has a simple but reliable setup and allows to accurately bend a rod, parallel to an ongoing surgical procedure and / or independent thereof, said rod being intended for stabilizing a spine of the patient after implementation. The rod bending device according to the disclosure usually comprises several modules as will be explained in more detail hereinafter. In a preferred variation, the rod bending device comprises a chuck and a bending head which are arranged displaceable with respect to each other. In difference to the devices known from prior art, complicated and - due to their play - imprecise mechanisms, which often entail the need for sensors to control the effective position, can be avoided. The chuck is preferably configured to receive and temporarily hold until the end of the bending process a first end of the rod to be bent according to the anatomy of the patient (respectively a screw configuration attached to the spine of the patient). The chuck is usually directly attached to and driven by a rotation motor arranged rotatable about a first axis. If appropriate, a gear box, preferably a planetary gearbox having low play, can be arranged between the chuck and the rotation motor coupling those two form a compact unit which usually is arranged displaceable with respect to the bending head, respective the motor which drives the bending head as will be described in more detail hereinafter. The rod bending device further comprises a linear displacement motor to displace the chuck including the rotation motor and if present the gearbox forming together the compact unit relative to the bending head in the direction of the first axis. The bending head usually comprises a first abutment and a thereto relatively moveable second abutment driven by a bending motor to bend the rod around a bending edge arranged at the first abutment.

[0013] In a simple, robust and easy to maintain variation, at least the bending head and the chuck, as well as the rotation motor, the linear displacement motor and the bending motor are arranged directly or indirectly on a common primary platform in a fixed and / or displaceable manner with respect to each other. Usually no outside housing is needed such that the modules may be arranged accessible from the outside. A primary platform allows a common reference point of the specified parts of the rod bending device. In a variation, the chuck and the thereto interconnected rotation motor may be arranged on a secondary platform arranged displaceable relatively to the bending head arranged on the primary platform. Depending on the field of application, an inverse arrangement is possible, i.e. the bending head is arranged on the displaceable secondary platform, while the chuck is arranged on the primary platform. In a variation, the chuck may be arranged linearly displaceable relative to the bending head along a linear guide rail.

[0014] Simple but reliable design with high accuracy with respect to relative positioning can be obtained in that the drive shaft of the linear displacement motor is coupled by a cog wheel to a cog rail which is attached to the static first platform or to the displaceable second platform, while the displacement motor is arranged on the displaceable second platform or the static first platform vice-versa.

[0015] For optimal usability in surgery the rod bending device is preferably designed not to expose parts into the open which prevent sterilization. Such parts may be enclosed in casings and sealed. An example of such parts are electrical parts. An example of such electrical parts are the motors, preferably the linear displacement motor and the rotation motor. Sterilization is any process that removes, kills, or deactivates all forms of life.

[0016] Good results can be achieved when the bending edge is a rounded edge with a radius of 0.5mm to 10 mm, preferably 6mm to 7 mm, more preferably 5 mm. Depending on the field of application other radii may be appropriate.

[0017] In a preferred simple and reliable variation at least one, preferably all, of the motors, of the rod bending device are attached to a gearbox, for instance in order to magnify the torque compared to the output torque of the motor and to prevent unwanted displacement relative to each other which may affect the processing of the rod to be bend. By the gearbox it is possible to achieve a self-locking arrangement and a high resolution with respect to the displacement steps in any of the three movements. In a variation, the chuck is interconnected to the rotation motor by a gearbox, preferably a planetary gearbox with less play. Additionally or alternatively, the chuck and / or the bending head are interconnected to the linear displacement motor by a gearbox, preferably a planetary gearbox. Additionally or alternatively, the second abutment is interconnected to the bending motor by a gearbox, preferably a planetary gearbox. Good results can be achieved when, at least one, preferably all, of the motors, of the rod bending device are attached to a planetary gearbox. This has the advantage of a compact design and a high positioning accuracy. The motors are preferably stepper motors or brushless DC-motors or the like which allow position control. Alternatively or in addition per motor a position encoder can be foreseen if appropriate to further increase the position accuracy. The position encoder can be arranged outside of the respective motor / gearbox or inside one of them. If present, the at least one encoder is preferably arranged close to the respective drive shaft. When motors and gearboxes are sealed, the above described combination offers a design which is sterilizable.

[0018] The rod bending device may comprise a battery as power supply for the onboard devices such as the electric motors and if present the controller to operate the rod bending device under sterilized conditions. The rod bending device can be charged before operation. In particular, it is independent of an external power supply and cables which may cause difficulties in a surgery room can be prevented.

[0019] A compact and reliable design can be achieved when at least the drive shaft of the bending motor and the drive shaft of the rotation motor are arranged perpendicular with respect to each other. If present this applies to the drive shafts of the respective gearboxes. Such an arrangement has the advantage that it prevents complicated designs as known from the prior art. In addition, a drive shaft of the linear displacement motor may be arranged perpendicular with respect to other drive shafts. Thereby it is possible to prevent complicated transition mechanisms as known from the prior art.

[0020] With respect to the quality of the processed rod after bending, good results can be achieved when the rotation axis of the drive shaft of the bending motor and the rotation axis of the drive shaft of the rotation motor meet each other in space. Thereby it is possible to bend the rod along its neutral line. The bending head is adopted accordingly.

[0021] In a preferred variation, the bending head comprises an inlet opening which merges into a guide channel. During operation the rod enters the bending head across the inlet opening in its longitudinal direction. The rod is supported by the guide channel in lateral direction, such that during bending the rod cannot displace in a manner which results in unwanted distortion. Further, this helps to prevent harming nearby personnel. The inlet opening and the guide channel preferably have a cross-section which corresponds to the rod to be bent.

[0022] The chuck is foreseen to receive and temporarily hold the rod to be bent. The chuck usually comprises a stop for positioning the rod in longitudinal direction during insertion of the rod into the chuck. Thereby it is assured that the rod is placed in a uniquely defined position in longitudinal direction. In a variation, the chuck comprises a specific interface which corresponds e.g. with respect to its cross-section to a specific interface of the rod. By this combination it is possible to avoid insertion of incompatible rods. Good results can be achieved when the interfaces match to each other in a form fit manner, for instance a square chuck and a square end on the rod or a hexagonal chuck and a hexagonal end on the rod. If appropriate, the chuck and the rod may have an alignment sign giving a uniquely defined position in rotational orientation with respect to each other. If appropriate, the chuck may comprise clamping means to clamp during operation the first end of the rod. The rod bending device may comprise a controller which is communicatively interconnected to the rotation motor, the linear displacement motor, and the bending motor. The controller is configured to bend a rod along its length and rotational position according to a bending dataset based on measured positions of at least two or at least three pedicle screws during surgical treatment of a patient. Usually, the rod will be bent at points in front and after the point at which a screw is intended to hold the rod. The bending dataset comprises per bending position (the position where the rod shall be bent) three parameters. The three parameters usually are longitudinal distance position along the rod with respect the first end of the rod attached to the chuck, the rotational position with respect to rotation axis of the chuck and bending angle with respect to the displacement of the second abutment during bending operation. A homing sequence may be run after startup. During the homing sequence, the bending motor and the linear displacement motor may be set to a stop position at which further movement is prevented, this position being the unactuated position of the second abutment abutting a stop in case of the bending motor and the maximum distance between bending head and chuck in case of the linear displacement motor. During the homing sequence, the rotation motor may be set to an arbitrarily chosen but repeatable zero-angle.

[0023] The steps performed by the rod bending device per bending position comprise: rotating the chuck by activating the rotation motor to a determined rotational position; displacing the chuck relative to the bending head by activating the linear displacement motor to a determined longitudinal distance position; deflecting the second abutment relative to the first abutment by activating the bending motor to a determined bending angle. Usually, steps a and b are performed before step c, though their order may be in reverse. In a preferred variant, steps a and b may be performed in parallel, which saves computation time. Performing all three steps in parallel is also conceivable.

[0024] In a preferred variation, the controller is a microcontroller. The communicative interconnection to the motors may be wired or wireless. In a variation, the controller may be distributed, in that circuit parts of the controller are arranged adjacent to at least one motor, and the circuit parts communicate between each other via wired or wireless connection.

[0025] In a variation, the bending dataset may comprise a plurality of bending positions. The determined rotational position may be given as a rotation coordinate with respect to a predefined zero-angle. The determined longitudinal distance position may be given as a longitudinal distance at which the linear displacement motor comes to a stop at which the distance between chuck and bending head is at its maximum, or at which the distance is at its minimum. The determined bending angle may be given as the angle to which the bending motor should deflect the second abutment. Preferably, the determined bending angle is already taking into consideration a spring back of the rod material, which is compensated by over-bending. In a variation, the measured positions of at least two or at least three pedicle screws during surgical treatment of a patient, on which measured positions the bending dataset is based on, may be retrieved by a navigation system or image data, for instance from an optical system. If appropriate, the image data may comprise data retrieved from external imaging devices. Examples of external imaging devices are mixed-reality headsets (such as Microsoft HoloLens), general camera-based positioning devices, single-use cameras, X-ray imaging systems, computer tomography imaging systems or ultrasound imaging systems.

[0026] If appropriate, the controller may comprise a memory and the controller is communicatively connected to a computing device, the controller further configured to receive the bending dataset from the computing device and store the bending dataset in the memory. The computing device may be general purpose computer or an external imaging device as described above. There may even be both, a general purpose computer or an external imaging device, communicatively connected to the rod bending device and to each other. The memory may be a volatile or non-volatile memory. The memory may also comprise instructions, which, when executed by the controller, cause the controller to carry out the method of bending of a rod according to one of the variations disclosed herein. If appropriate, the received bending dataset may be based on image data of the anatomy of the patient, the image data captured by an external imaging device during an ongoing surgical procedure, the external imaging device being communicatively connected to the controller.

[0027] If appropriate, the received bending dataset may be based on preoperative data based on image data and / or correction data of the anatomy of the patient. If appropriate, correction data may comprise functions describing the intended correction alignment of the spine of the patient.

[0028] The above-identified objects are further addressed by a second aspect of the disclosure of a system for bending a rod according to the anatomy of a patient, parallel to an ongoing surgical procedure, said rod intended for stabilizing a spine of the patient. The system comprises a rod bending device according to the first aspect of the disclosure, a camerabased positioning device and a computing device. The computing device may be placed external to the rod bending device and / or in the controller of the rod bending device and / or in the camera-based positioning device. The computing device is configured to: i. determine measured positions of at least two pedicle screws, based on image data received from the camera-based positioning device ii. determine a bending dataset comprising per bending position three parameters of a longitudinal distance position along the rod with respect the first end of the rod attached to the chuck, a rotational position with respect to rotation axis of the chuck and a bending angle with respect to the displacement of the second abutment during bending operation; and iii. control the rod bending device (1) to bend the rod according to the bending dataset.

[0029] The system comprises a rod bending device according to the first aspect of the disclosure. The system further comprises and a camera-based positioning device communicatively connected to the controller of the rod bending device.

[0030] The camera-based positioning device may be a single-use or multiple-use camera AR- glasses, a plurality of cameras or other sensors allowing the calculation of the 3D position of the screws. The communication connection between the camera-based positioning device and the controller may be wired or wireless. Preferably, the communication connection is wireless, for instance via a Wireless Local Area Network (WLAN).

[0031] The above-identified objects are further addressed by a third aspect of the disclosure of a method for bending a rod according to the anatomy of a patient, parallel to an ongoing surgical procedure, said rod intended for stabilizing a spine of the patient.

[0032] The above-identified objects are further addressed by a fourth aspect of the disclosure of a computer program product, comprising instructions, which, when carried out by a controller of a device, cause the rod bending device to carry out the method according to any one of the third aspect of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered limiting to the disclosure described in the appended claims. The drawings in which: Fig. 1 shows in a first perspective view an embodiment of the rod bending device with a rod to be bent;

[0034] Fig. 2 shows in a second perspective view the embodiment of the rod bending device with a rod to be bent;

[0035] Fig. 3 shows a first abutment and a second abutment of a bending head of the embodiment of the rod bending device in a first perspective view of the outtake C from Fig. 1 (Fig. 3a) and a second perspective view of the outtake A from Fig. 2 (Fig. 3b);

[0036] Fig. 4 shows the embodiment of the rod bending device in a side view;

[0037] Fig. 5 shows the embodiment of the rod bending device in a backside view; Fig. 6 shows a cut-out perspective view on the front of the embodiment of the rod bending device, in particular showing the bridge support, the bending head and the bending motor and the rod which is currently being bent;

[0038] Fig. 7 shows a schematic visualization of a system comprising a rod bending device, an computing device and a camera-based positioning device. DESCRIPTION OF THE EMBODIMENTS

[0039] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts. For the sake of improved clarity in the drawings, where multiple of the same features are shown, not all instances of the same features may be labeled with reference numbers to reduce clutter.

[0040] Figure 1 shows a first embodiment of a rod bending device 1 in a perspective view from above and right. Figure 2 shows the embodiment according to Figure 1 in a perspective view from above and left. Figure 3a shows detail A from Figure 1 in a magnified manner. Figure 3b shows detail B from Figure 2 in a magnified manner. Figure 4 shows the embodiment according to Figure 1 in a side view. Figure 5 shows the embodiment of Figure 1 in a backside view. Figure 6 shows a cut-out the front side of the embodiment from the same perspective view as Figure 2.

[0041] Figures 1 and 2 show in a first and second perspective view an embodiment of the rod bending device 1 with a rod 3 to be processed. The rod 3 is already partially bent according to an anatomy of a patient, respectively the pedicle screws applied to the anatomy of the patient (both not visible). The rod 3 is intended to be interconnected to the pedicle screws and stabilizing a spine of the patient at least during a healing process. The rod 3 is bent in a sequential manner at different locations along its length, point after point. The different parts of the rod bending device 1 are arranged onto a primary platform 81. A chuck 2 is configured to receive and temporarily hold a first end 31 of the rod 3 to be bent. The chuck 2 is attached to a drive shaft 42 of a rotation motor 4, respectively a gearbox 41 if present. In the shown variation, the rotation motor 4 rotates the rod 3 about a first axis Y, which extends in the current presentation in y-direction. In the shown configuration the rotation motor 4 is a stepper motor or a brushless DC motor. In particular, the rotation motor 4 is a motor which can turn the rod to a distinct rotational position. The rotation motor 4 is interconnected to circuitry (not shown in detail) that can be programmed to set the drive shaft 42 to an angle with respect to a reference angle. Consequently, also the chuck 2 and the rod 3 are set to the rotational position. As visible, the rotation motor 4 is attached onto a top side of a secondary platform 82. Better visible in Figures 4 and 5 is a linear displacement motor 5 attached onto a bottom side of the secondary platform 82, which has a drive shaft 52 arranged in a second horizontal axis x, perpendicular to the first axis y. The drive shaft 52 is coupled to one of two linear guide rails 83 which are interconnected to the primary platform 81 via being attached to two column supports 84 on the back side of the primary platform 81 and being attached to a bridge support 85 on the front side of the primary platform 81.

[0042] In the shown variation, the bridge support 85 comprises three parts, two edge parts and an upper bridge part, attached to each other forming a U-shape standing on the primary platform and seen in y-direction. Two edge parts are attached to the primary platform 81 . The bridge part which is attached to each of the two edge parts has a substantially circular cavity cut into its surface and a bending head 7 attached onto its top side. On the bridge part, the bending head 7 is placed further towards the side at which the chuck 2 is placed than the cavity. Below the bridge support 85, a bending motor 6 and a gearbox of the bending motor 61 are attached to the platform 81 . The casing of the bending motor 6 and its gearbox 61 is attached to the bottom side of the upper bridge part. The rod bending device 1 further comprises a controller 9, arranged in a separate casing on the primary platform 81. The controller 9 usually comprises a memory set up as a volatile cache. The controller 9 is configured to receive a bending dataset, wirelessly, via a wireless communication module. The bending dataset may be a 3 x n-matrix (wherein n is the number of bending positions), resp. a vector of n bending positions. Each bending position usually is a vector with three entries, the three entries corresponding to data indicative of the rotational position, the longitudinal distance and the bending angle. The controller 9 is communicatively connected to the rotation motor 4, the linear displacement motor 5 and the bending motor 6, respectively their addressable circuitry each comprising a wireless communication module. The controller 9 is configured to send instructions to the motors 4, 5, 6. The controller 9 is configured to send the instruction to the rotation motor 4 to rotate the chuck to the rotational position and the instruction to the linear displacement motor 5 to displace the chuck 2 relative to the bending head. The controller 9 is further configured, after having the rod 3 positioned accordingly, to deflecting the second abutment 72 relative to the first abutment 71 by activating the bending motor 6 to the bending angle. This procedure is repeated for all the n bending position of the bending dataset. The motors resp. their circuitry may comprise or be interconnected to feedback sensors, which may feed realtime data to the motor circuitry and via communication modules back to the controller 9, such that the controller may interrupt a running process.

[0043] The rod bending device 1 further comprises a battery 10, arranged in a separate casing on the primary platform 81. The battery 10 is connected via power lines to the back part of the rotation motor 4 and the back part of the linear displacement motor 5. The battery is further connected to the bending motor 6 and the controller 9 via power lines along the primary platform 81. Figure 3a and 3b show a first abutment 71 and a second abutment 72 of a bending head 7 of an embodiment of the rod bending device 1 in a first perspective view from Fig. 1 (Fig. 3a) and a second perspective view from Fig. 2 (Fig. 3b). Fig. 3a shows the rod 3 entering an inlet opening 73 of the bending head 7, which inlet opening 73 merges into a guide channel. The inlet opening 73 is part of the first abutment 71. The second abutment 72 is in the shown variation a circular piece with an (oval) extrusion pointing out at the top side offset from the center of the circular piece. Depending on the field of application, other designs are possible. The circular piece of the second abutment 72 is mounted to the drive shaft 62 of the bending motor 6, for instance via form- and / or press- fit and / or being attached to each other. The rod 3 that enters into the first abutment 71 passes through the guide channel of the first abutment 71 , and passes by the second abutment 72 in an unactuated position. While the second abutment 72 is driven via the bending motor 6 into an actuated position, the second abutment 72 pushes the rod 3, which is still confined in its position by the guide channel of the first abutment 71. The second abutment 72 in particular bends the rod 3 around a bending edge 74 arranged at the first abutment 71. In the shown variation, the bending edge 74 is an edge of the first abutment 71 that is rounded by a radius of here 5 mm (other values are possible).

[0044] Figure 4 shows an embodiment of the rod bending device 1 in a side view and Figure 5 shows an embodiment of the rod bending device 1 in a backside view. These Figures show a pronounced view on the secondary platform 82. The rotation motor mount 43 is attached on top of the secondary platform 82 and the rotation motor 4 respectively its casing is attached to the rotation motor mount 43. In the shown embodiment, the linear displacement motor 5 is attached to the secondary platform 82 at the bottom via the linear displacement motor mount 53. The drive shaft 42 interconnected to the rotation motor 4 is aligned in the first direction y. The drive shaft 52 interconnected to the linear displacement motor 4 is aligned perpendicular to the first direction y, namely along the x direction. The centerline of the rod 3 in Figure 4 is highlighted in a broken line. In this embodiment, a cog wheel is attached to the drive shaft 52 of the linear displacement motor 5. The drive shaft 52 is coupled by the cog wheel to a cog rail which is attached to one of the guide rails 83.

[0045] Figure 6 shows a cut-out perspective view on the front of the embodiment of the rod bending device 1 , in particular showing the bridge support 85, the bending head 7, the bending motor 6 and the rod 3 which is currently being bent. The view angle is the same as the view angle of Figure 2. The trajectory of central axis of the rod 3 is highlighted in a broken line. It is apparent that the rod was already bent at a previous point and is currently being bent at a second point.

[0046] In the shown moment of the process, the controller 9 has already activated the rotation motor 4 to rotate the chuck 2 to the rotational position and has activated the linear displacement motor 5 to displace the chuck 2 relative to the bending head 7 to the longitudinal distance position.

[0047] The first axis Y, which extends in the current presentation in y-direction, corresponds to the axis of the chuck and the axis of the rotation motor. That first axis Y corresponds to the central axis of the rod 3 up to the point at which the rod may be bent. The axis Z of the drive shaft 62 interconnected with the bending motor 6 is highlighted as the broken line which extends in the current presentation in z-direction. It is apparent from the figure that the axes Y and Z meet each other in space. The rod 3 is bent at substantially that point by actuating, in particular actuating by the controller 9, the bending motor 6 to rotate the second abutment 72, in particular to rotate the oval extrusion 75 pointing out at the top of the circular piece 76 of the second abutment 72 offset from the center of the circular piece 76 from an unactuated into an actuated position by a bending angle. The surface point at which the oval extrusion 75 acts on the rod 3 is on the opposite side of the rod 3 with respect to the bending edge 74 and longitudinally displaced along the first axis Y with respect to the bending edge 74. By rotating the oval extrusion 75 but having the guide channel firmly holding the rod 3 part that is surrounded by the guide channel, a force is applied onto the rod 3, which is acted upon such that between the oval extrusion 75 and the bending edge 74, the rod 3 is compressed on the side of the bending edge 74 and stretched on the side of the oval extrusion 75, thereby being bent by the bending angle.

[0048] Figure 7 shows a schematic visualization of a system 12 comprising a rod bending device 1 , a computing device 11 (Fig. 10a), and a camera-based positioning device. The controller 9 of the rod bending device 1 is preferably wireless connected to a computing device 11 (connection schematically indicated by dashed line), from which the bending dataset is received in the controller 9 and saved to the memory 91. The bending process is initiated once the bending dataset is available in memory 91. Alternatively or additionally, a camera-based positioning device 11a such as a camera is communicatively connected to the computing device 11 and optionally also the controller 9 of the rod bending device 1 . The computing device 11 is configured to convert image data of an anatomy of a patient, such a spine, in particular pedicle screw head location and orientation data, into a contoured rod resp. a bending dataset to transmit to the controller 9. In particular, the computing device 11 may be configured to determine the three parameters of the bending dataset (longitudinal distance position, rotational position and bending angle) based on the pedicle screw head location and orientation data in turn based on image data. Optionally, the computing device may be configured to determine the bending angle with additional information about the rod material, for example the degree of spring back of the rod material that needs to be compensated by over-bending. Optionally, the computing device may be configured to determine the bending dataset based not only on image data received from the camera-based positioning device 11a, but also preoperative data based on image data and / or correction data of the anatomy of the patient. It goes without saying that the wireless communication between the entities (controller 9, computing device 11 and camera-based positioning device 11a) may be performed over a wireless communication module to the respective entity.

[0049] In order to allow repeatable outcomes of a bent rod 3, the three parameters are usually defined relative to the state of the rod bending device 1 after a homing sequence is run after start-up. The bending motor 6 and the linear displacement motor 5 may be set to a stop position at which further movement is prevented, e.g. determined by a large power consumption or sensory data implying that there is no further movement. A determined position can be achieved when, the bending motor 6 is rotated as far as to abut the first abutment 71 and the second abutment 72, and upon reaching that limit, the power consumption rises which triggers a stop and a backwards rotation by a determined amount to provide clearance to insert the rod 3 to be bend.

[0050] The above-described embodiments of the disclosure are exemplary and the person skilled in the art knows that at least some of the components and / or steps described in the embodiments above may be rearranged, omitted, or introduced into other embodiments without deviating from the scope of the present disclosure.

[0051] REFERENCE SIGNS

[0052] 1 rod bending device 72 second abutment

[0053] 2 chuck 73 inlet opening

[0054] 3 rod (to be bent) 74 bending edge

[0055] 31 first end of the rod 30 75 oval extrusion of the second

[0056] 4 rotation motor abutment

[0057] 41 gearbox of the rotation motor 76 circular piece of the second

[0058] 42 drive shaft of the rotation motor abutment resp. of the gearbox of the rota81 primary platform tion motor 35 82 secondary platform

[0059] 43 rotation motor mount 83 linear guide rail

[0060] 5 linear displacement motor 84 column support

[0061] 51 gearbox of the linear displace85 bridge support ment motor 9 controller

[0062] 52 drive shaft of the linear displace40 91 memory ment motor resp. of the gearbox 10 battery of the linear dis11 computing device placement motor 11a camera-based positioning de¬

[0063] 53 linear displacement motor mount vice

[0064] 6 bending motor 45 12 system for bending a rod

[0065] 61 gearbox of the bending motor 13 spine

[0066] 62 drive shaft of the bending motor Y first axis I axis of the drive shaft resp. of the gearbox of the interconnected with the rotation bending motor motor

[0067] 7 bending head 50 Z axis of the drive shaft intercon¬

[0068] 71 first abutment nected with the bending motor

Claims

CLAIMS1. A rod bending device (1) for bending a rod according to an anatomy of a patient comprising: a. a chuck (2), configured to receive and temporarily hold a first end (31) of the rod (3) to be bent according to the anatomy of the patient, said chuck (2) being arranged rotatably about a first axis (Y) driven by an electric rotation motor (4) directly coupled to the chuck (2); b. an electric linear displacement motor (5) configured to displace the chuck (2) relative to a bending head (7) in the direction of the first axis (Y); and c. said bending head (7) comprising a first abutment (71) and a thereto relatively moveable second abutment (72) driven by an electric bending motor (6) to bend the rod (3) around a bending edge (74) arranged at the first abutment (71).

2. The rod bending device (1) according to claim 1 , wherein the bending head (7) and the chuck (2), as well as the rotation motor (4), the linear displacement motor (5), and the bending motor (6) are arranged directly or indirectly on a common primary platform (81) in a fixed or displaceable manner.

3. The rod bending device (1) according to claim 2, wherein a. the chuck (2) and the thereto coupled rotation motor (4) are arranged on a secondary platform (82) arranged displaceable relatively to the bending head (7) arranged on the primary platform (81) orb. the bending head (7) is arranged on a secondary platform (82) arranged displaceable relatively to the chuck (2) and the thereto coupled rotation motor(4) arranged on the primary platform (81).

4. The rod bending device (1) according to any of the preceding claims, wherein the chuck (2) and the bending head (7) are arranged linearly displaceable relative to each other along a linear guide rail (83).

5. The rod bending device (1) according to any of the preceding claims, wherein the rod bending device is designed at least partially sterilizable.

6. The rod bending device (1) according to any of the preceding claims, wherein a. the chuck (2) is coupled to the rotation motor (4) by a gearbox (41), preferably a planetary gearbox and / or b. the chuck (2) and / or the bending head (7) are interconnected to the linear displacement motor (5) by a gearbox (51), preferably a planetary gearbox and / or c. the second abutment (72) is interconnected to the bending motor (6) by a gearbox (61), preferably a planetary gearbox.

7. The rod bending device (1) according to any of the preceding claims, wherein at least one of the motors (4, 5, 6) is a stepper motor or a brushless DC-motor.

8. The rod bending device (1) according to any of the preceding claims, wherein the rod bending device (1) comprises a battery (10) as power supply for at least the electric motors (4, 5, 6) and / or an optional controller (9).

9. The rod bending device (1) according to any of the preceding claims, wherein a. a drive shaft (62) of the bending motor (6) respectively a drive shaft of the gearbox (61) of the bending motor (6) and b. a drive shaft (42) of the rotation motor (4) respectively a drive shaft of the gearbox (41) of the rotation motor (4) are arranged perpendicularly with respect to each other.

10. The rod bending device (1) according to any of the preceding claims, wherein a. a drive shaft (52) of the linear displacement motor (5), respectively a drive shaft (52) of the gearbox (51) of the linear displacement motor (5) and b. a drive shaft (42) of the rotation motor (4) respectively a drive shaft (42) of the gearbox (41) of the rotation motor (4) are arranged perpendicular with respect to each other.

11. The rod bending device (1) according to any of the preceding claims, wherein a. an axis (Z) of a drive shaft (62) of the bending motor (6) respectively a drive shaft of the gearbox (61) of the bending motor (6) and b. an axis (Y) of a drive shaft (42) of the rotation motor (4) respectively a drive shaft of the gearbox (41) of the rotation motor (4) meet each other in space.

12. The rod bending device (1) according to any of the preceding claims, wherein the bending head (7) comprises an inlet opening (73) which merges into a guide channel, whereby by operation the rod enters the bending head (7) across the inlet opening (73) in its longitudinal direction (7).

13. The rod bending device (1) according to any of the preceding claims, wherein the chuck (2) comprises a stop (23) for positioning the rod (3) in longitudinal direction.

14. The rod bending device (1) according to any of the preceding claims, wherein the chuck (2) comprises a first interface (22) configured to receive a second interface (32) arranged at the first end (31) of the rod (3).

15. The rod bending device (1) according to any of the preceding claims, wherein the chuck (2) comprises a clamping means (21) to clamp during operation the first end (31) of the rod (3).

16. The rod bending device (1) according to any of the preceding claims, wherein the rod bending device further comprises a controller (9) which is communicatively interconnected to the rotation motor (4), the linear displacement motor (5), and the bending motor (6), the controller (9) being configured to bend a rod according to a bending dataset based on measured positions of at least two pedicle screws during surgical treatment of a patient, the bending dataset comprising per bending position three parameters of a longitudinal distance position along the rod with respect the first end of the rod attached to the chuck, a rotational position with respect to rotation axis of the chuck and a bending angle with respect to the displacement of the second abutment during bending operation, wherein bending the rod comprises:rotating the chuck (2) by activating the rotation motor (4) to the rotational position; displacing the chuck (2) relative to the bending head (7) by activating the linear displacement motor (5) to the longitudinal distance position; deflecting the second abutment (72) relative to the first abutment (71) by activating the bending motor (6) to the bending angle.

17. The rod bending device (1) according to the claim 16, wherein the controller (9) comprises a memory (91) and the controller is communicatively connected to an computing device (11), the controller (9) further configured to receive a bending dataset from the computing device and store the bending dataset in the memory(91).

18. A system (12) for bending a rod according to an anatomy of a patient, the system (12) comprising: a. a rod bending device (1) according to any of the preceding claims; b. a camera-based positioning device (11a); and c. a computing device (11) configured to: i. determine measured positions of at least two pedicle screws of a patient, based on image data received from the camera-based positioning device (11a);ii. determine a bending dataset comprising per bending position three parameters of a longitudinal distance position along the rod with respect the first end of the rod attached to the chuck, a rotational position with respect to rotation axis of the chuck and a bending angle with respect to the displacement of the second abutment during bending operation; and iii. control the rod bending device (1) to bend the rod according to the bending dataset.

19. A method for bending a rod (3) according to the anatomy of a patient, wherein the rod is bent with a rod bending device comprising: a. a chuck (2), configured to receive and temporarily hold a first end (31) of the rod (3) to be bent according to the anatomy of the patient, said chuck (2) being arranged rotatably about a first axis (Y) driven by an electric rotation motor (4) directly coupled to the chuck (2); b. an electric linear displacement motor (5) configured to displace the chuck (2) relative to a bending head (7) in the direction of the first axis (Y); and c. said bending head (7) comprising a first abutment (71) and a thereto relatively moveable second abutment (72) driven by an electric bending motor (6) to bend the rod (3) around a bending edge (74) arranged at the first abutment (71); and wherein the rod is bent according to a bending dataset based on measured positions of at least two pedicle screws, the bending dataset comprising per bendingposition three parameters of a longitudinal distance position along the rod with respect the first end of the rod attached to the chuck, a rotational position with respect to rotation axis of the chuck and a bending angle with respect to the displacement of the second abutment during bending operation, wherein bending the rod comprises, the method comprising the steps: rotate the chuck (2) by activating the rotation motor (4) to the rotational position; displace the chuck (2) relative to the bending head (7) by activating the linear displacement motor (5) to the longitudinal distance position; deflect the second abutment (72) relative to the first abutment (71) by activating the bending motor (6) to the bending angle.

20. A computer program product, comprising instructions, which, when carried out by a controller of a device, in particular the controller (9) of the rod bending device (1), cause the rod bending device (1) to carry out the method according to claim 19.

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