Bone screw tightening device

Abstract

METHOD, DEVICE AND SYSTEM FOR PREVENTING LATERAL STRESS IN BONE STRUCTURES RESULTING FROM OFF-AXIS FORCES CAUSED BY A SCREWDRIVER AND SCREW EXTENDER. The present invention relates to a bone screw tightening device that includes a screwdriver, wherein the screwdriver has along its geometric axis a device to provide radial bendability while preserving torsional rigidity along a longitudinal geometric extension axis of the screw.

Description

1 / 21 Bone Screw Tightening Device - Cross-Reference to Related Requests

[001] This patent application claims priority to International Patent Application No. PCT / IB2019 / 055640, filed on July 2, 2019, the contents of which are incorporated herein by reference in their entirety. FIELD OF THE INVENTION

[002] The present invention relates to the field of surgical methods using bone screws that can be attached to a bone, for example, a vertebra, and methods, devices and systems for tightening or fixing a bone screw to a bone. BACKGROUND OF THE INVENTION

[003] In the field of surgery, when a surgeon or operator needs to attach or fix a bone screw to a bone, for example, to fasten or fix a bone, bone fragments, or different bones together, for example, through a surgical incision in a living organism, often a first geometric axis defined by an extension of the bone anchor part of the bone screw and a second geometric axis defined by the screwhead of the fixation tool will become misaligned. Ideally, if the screw head and the bone anchor of the bone screw are monoaxial, the first and second geometric axes should be kept on the same geometric axis relative to each other. Misalignment is usually the result of poor vision that a surgeon or operator has of the surgical site, or of very limited or non-existent vision of the actual geometric axis that the bone anchor has within the bone.Misalignment can force the first geometric axis of the bony anchor from its initially desired positioning and geometric axis, thus moving the bone out of its initial position. This can lead to problems with parasitic lateral torques, tensions, or stresses between the bony anchor of the head of the bone. Petition 870250034043, dated 04 / 29 / 2025, page 10 / 65 2 / 21 spindle and bone, which may remain even after surgery. Furthermore, surgeons tend to apply strong torques to the fixation tool while the first geometric axis and the second geometric axis are misaligned, so that lateral stresses are exacerbated.

[004] For example, in the field of orthopedic surgery, the patent in US10,058,355, the reference of which is incorporated herein by reference in its entirety, describes an orthopedic implant kit that provides a pedicle screw, a corresponding fixation screw, a rod, and the tools for operating them, which includes a screw extender to retain the pedicle screw and a fixation screw wrench to tighten the fixation screw in a threaded manner relative to the screw head of the pedicle screw. With this tool kit, it is possible for the threaded part of the bone screw to be fixed to a bone, for example, a vertebra, and since a connection between the screw wrench and the screw head can be very rigid, any tightening of the bone screw outside the first originally defined geometric axis will lead to lateral stress to which the bone will also be subjected.Furthermore, although the orientation of the screw head can be given by the orientation of the shank that is placed within a groove in the screw head, and ideally the shank should be arranged perpendicular to the geometric axis defined by the screw head, by misaligning the geometric axis defined by a fixation screw that is retaining the shank within the groove, for example, with the fixation screw wrench, the screw head may be subjected to unwanted lateral stresses that will lead to stress applied to the bone to which the bone screw is fixed. These unwanted lateral stresses can lead to substantial problems after surgery and may be felt as chronic pain by the living being after surgery, and may also lead to... Petition 870250034043, dated 04 / 29 / 2025, page 11 / 65 3 / 21 due to inadequate healing of bone structures affected by surgery. Lateral stresses can also lead to overloading of the implants, which in turn can lead to material failure or loosening of the implant, for example, after surgery.

[005] Therefore, there is a great need for substantially improved solutions to provide bone fixation systems and orthopedic implant kits for surgeons, physicians, and laboratory operators, in light of the deficiencies discussed above. Additionally, there is a strong need to provide tools or devices that can measure a geometric axis of orientation of a bone fixation rod relative to a central geometric axis of a pedicle screw head. BRIEF DESCRIPTION

[006] According to one aspect of the present invention, a bone screw tightening device is provided which includes a screw wrench, wherein the screw wrench has along its geometric axis a device to provide radial bendability and at the same time preserve torsional rigidity along a geometric axis of longitudinal extension of the screw.

[007] According to another aspect of the present invention, a device for measuring an angle between a geometric axis of longitudinal extension of a bone fixation rod and a geometric axis of a screw head of a pedicle screw of an orthopedic implant kit is provided, wherein the device includes a device configured to be slid over a screw extender of the orthopedic implant kit.

[008] According to yet another aspect of the present invention, a device for measuring an angle between a geometric axis of longitudinal extension of a bone fixation rod and a geometric axis of a screw head of a pedicle screw from a kit. Petition 870250034043, dated 04 / 29 / 2025, page 12 / 65 A 4 / 21 orthopedic implant is provided, the device is preferably configured to be slid onto a screw extender from the orthopedic implant kit, the device has two distance measuring sensors opposite each other at one front end of the device, the distance measuring sensors are configured to measure a distance between the sensors and a rod position on each side of the screw head. BRIEF DESCRIPTION OF THE VARIOUS VIEWS OF THE DRAWINGS

[009] The attached drawings, which are incorporated into this document and form part of this descriptive report, illustrate the present preferred embodiments of the invention, and, together with the general description provided above and the detailed description provided below, serve to explain the features of the invention.

[0010] Figure 1 shows an exemplary orthopedic bone screw tightening system with screw wrench 26, handles 25, 29, engagement element 10 for bone screw 1, and bone screw 1 and bone V, which illustrates a potential problem when tightening screw 1 to bone V;

[0011] Figure 2 shows an exemplary bone screw tightening system with screw wrench 20, screw extender 6, fixation rod 7, polyaxial bone screw 1, fixation screw 3 to retain the rod 7 in the screw head 2, and vertebral bone V, illustrating another potential problem when tightening screw 1 to bone V;

[0012] Figures 3A to 3C show different embodiments with different devices associated with a bone tightening system for prevention of off-axis geometry, with Figure 3A showing a schematic and exemplary side view of a bone tightening system, which includes a screw extender, a screw wrench and a bone screw, with the bone screw having a bone anchor and a screw head, and polarized handles by Petition 870250034043, dated 04 / 29 / 2025, p. 13 / 65 5 / 21 springs 25, 29, Figure 3B shows a top view of an exemplary handle 290 for engaging with screw extender 6 and Figure 3C shows a top view of an exemplary handle 250 for engaging with screw wrench 20, 26;

[0013] Figure 4 shows a possible implementation of a UJ1 and / or UJ2 universal joint;

[0014] Figure 5 shows a helical tube, or other type of flexible rod, which can be used for one or more portions of screw wrench 26, for example, at locations UJ1 and UJ2;

[0015] Figures 6 to 8 represent, in an exemplary and schematic way, a device 100 that allows measurement and angulation between the geometric axis HA2 of screw extender 6 and screw head 2, and the geometric axis RA2 of the rod 7, or to determine if HA2 and RA2 are perpendicular to each other; and

[0016] Figures 9-10 represent, in an exemplary and schematic way, another device 200 that allows measurement and angulation between the geometric axis HA2 of screw extender 6 and screw head 2, and the geometric axis RA2 of the rod 7, or to determine if HA2 and RA2 are perpendicular to each other, by an active means.

[0017] In this document, for ease of understanding, identical numerical references have been used, where possible, to designate identical elements that are common to the Figures. In addition, the images are simplified for illustrative purposes and may not be represented to scale. DETAILED DESCRIPTION OF THE VARIOUS MODALITIES

[0018] Figure 1 shows a first representation that shows the problem that can be caused by a parasitic stress S2 that is present between the bone anchor 4 and bone screw 1, for example, when a surgeon or operator tightens screw 1 to bone V, for example, by means of handles 25, 29 and screw wrench 26. Petition 870250034043, dated 04 / 29 / 2025, page 14 / 65 6 / 21 Specifically, in this variant, the bone screw 1 can be a monoaxial screw where the head 2 and bone anchor 4 are fixed to each other, and always have the same orientation relative to each other. In this regard, they are oriented along a geometric axis HA1. Next, the screw wrench 26 is removablely engaged with the screw head 2 using the engagement part 10 and has a longitudinal extension geometric axis HA2. The screw head 2 is placed within a surgical incision SI that allows access to the screw head 2. It is possible that the operator or surgeon may not retain the geometric axis of screw wrench 26 HA2 on the geometric axis HA2 of bone screw 1 due to a movement outside the geometric axis S1.Since the connection between the screw wrench 26 and screw 1, in this variant, does not provide an angular change between HA1 and HA2, the movement S1 will cause tension S2 between the bone anchor 4 of screw 1 or will move bone V from its desired position outside the orientation defined by the geometric axis HA1.

[0019] Figure 2 shows a second representation illustrating the problem that can be caused by an operator or surgeon, specifically to an orthopedic fixation system, where a pedicle bone screw 1 has already been fixed to a vertebra V by the bone anchor 4, and then adjacent vertebrae are fixed by means of the pedicle bone screw 1 with a rod 7. The problem can be caused when the rod 7 is affixed or tightened to the head of the pedicle screw 1 by a fixation screw 3 that can engage in a threaded manner with the head 2, and has a groove to accommodate the rod 7. In this situation, the pedicle screw 1 is a polyaxial or multiaxial screw, where the head 2 and the threaded part or bone anchor 4 can assume different angular positions relative to each other, due to the joint, engagement or orientation mechanism 13. In this representation, the exemplary bone anchor 4 and the head 2 are shown as being Petition 870250034043, dated 04 / 29 / 2025, page 15 / 65 7 / 21 aligned on the same geometric axis, for example, where HA1 is equal to HA2, but these geometric axes can also be oblique to each other, as when a polyaxial screw is used.

[0020] For example, within the surgical incision SI, when tightening the fixation screw 3 into the screw head 2, the rod 7, which has a geometric axis of orientation RA2, may be positioned not perpendicular to the geometric axis HA2, which is primarily defined by the orientation of screw head 2. Due to the connection between screw head 2 and screw extender 6, and the screw wrench 20 for fixation screw 3 via fixation screw 3, the screw wrench 20 will have the same geometric axis as HA2. Once fixation screw 3 has been tightened, and the geometric axes HA2 and RA2 are not perpendicular to each other, as shown exemplarily in Figure 2, this can cause stress S1 to screw head 2, which will translate to stress S2 for vertebrae V, since rod 7 will be contiguous with one side of the screw head groove 2 and will not rest properly within the groove.As discussed above, in this variant, the screw head 2 can be freely orientable in relation to the bone anchor 4 with an orientation mechanism 13, thus forming a polyaxial screw, so that the geometric axis HA1 of the bone anchor 4 and the geometric axis HA2 of the screw head 2 may not coincide.

[0021] Due to the limited view afforded by the surgical incision SI to the surgeon or operator, and in some cases the oblique position of the geometric axis RA1 of the rod 7 in relation to an extension of the spine, it is possible that the screw head 2 and its orientation HA2 cannot be properly oriented in relation to the rod 7 without additional assistance, so that it is ideally positioned perpendicular to RA2. Once the fixation screw 3 is tightened, the polyaxiality of the pedicle screw 1 is generally lost, and for this reason the Petition 870250034043, dated 04 / 29 / 2025, page 16 / 65 8 / 21 screw head 2 may not automatically orient itself perpendicular to the rod 7 simply by tightening the fixing screw 3 onto the screw head 2 with the fixing screw wrench 3. Consequently, a device, system, or method is desired that can measure the orientation of the rod 7 relative to the screw head 2 during the surgical procedure, so that the surgeon or operator can properly orient the screw head 2 so that it is perpendicular or substantially perpendicular to the rod 7, before tightening the fixing screw 3 onto the head 2, for attachment of rod 7 to the pedicle screw 1.

[0022] According to one aspect of the present invention, as shown in Figure 3A in a side view and in a schematic and exemplary manner, a screw wrench 26 can be used which has more universal joints UJ1, UJ2, and a screw extender 6 can be used for removable attachment to a screw head 2 of a bone screw 1. An exemplary universal joint UJ is shown in Figure 4. This can be a way to limit any parasitic lateral torques to the screw head 2 and also to the bone anchor 4 (worn part) by the screw extender 6 and screw wrench attachment assembly 26. The mechanical configuration would use two different universal joints (UJ1 and UJ2) and a simple joint (SJ1), as discussed below.The basic operating principle is that the direction of the extension of screw extender 6 (SA2) and a fixing screw wrench 26 is given by the orientation of screw head 2 (SA3) of the pedicle screw 1, and not forcing the surgeon or operator to change the orientation SA3 by manipulating the screw extender 6 and / or the fixing screw wrench 26.

[0023] A universal joint UJ1 will be connected to the upper section 8 of the fastening screw wrench 26 with the lower section 20, so that the angular position of the geometric axis SA2 of the screw wrench Petition 870250034043, dated 04 / 29 / 2025, page 17 / 65 The lower clamping 9 / 21 can be decoupled from the geometric axis SA1 of the upper clamping screw wrench, while maintaining a fixed rotating angular connection with angles α1 and α5. Figure 4 shows an exemplary compact universal joint UJ that could be easily integrated into a screw extender. This feature allows for added foldability to the clamping screw wrench 26 or other type of screw wrench, while preserving torque transmission from the handles 25, 26 to the clamping screw 3 or other type of bone screw, since the titanium or stainless steel clamping screw wrench 26 is very rigid.

[0024] Furthermore, if a screw extender 6 is used, a portion of screw extender 6 below where handles 25, 29 may be located may also become less rigid in a direction opposite to the geometric axis SA1 than the remaining part of the screw extender, but, while substantially preserving the torsional rigidity of the screw extender, especially less rigid than the portion of the screw extender that engages with the screw head 2 of pedicle screw 1. Specifically, the screw extender 6 may become more pliable relative to a geometric axis SA1, but still preserve a relatively high torsional rigidity to transmit torque. For example, slots or openings OS for the screw extender 6 in an area below the attachment area of ​​handle 29 may be such that lateral torques off the geometric axis SA1 are much less strong when transmitted through the screw extender 6.The screw extension 6 could become more foldable off the SA1 geometric axis in that area by adding additional slots or other types of OS openings, wherein the slots are perpendicular to the SA1 geometric axis, for example, as alternating angular slots, or a softer material could be used in that area. This allows for added foldability. Petition 870250034043, dated 04 / 29 / 2025, page 18 / 65 10 / 21 additional to screw extender 6 without impacting its function of guide rods 7 and fixing screw wrench 26. This area is on an upper part of screw extender 6, and therefore will have only minimal impact on its operation, i.e., the worn engagement between fixing screw wrench 26 and screw extender 6. Furthermore, the area with OS openings or element that provides lateral smoothness may be such that it rests in a range of the location where the universal joint UJ of screw wrench 26 will be located, when engaging with fixing screw 3, or other type of bone screw 1.

[0025] A second universal joint UJ2 can be arranged between handle 25 and the upper section 8 of the screw wrench 26. This allows locking of the angle rotation α1 of the upper section 8 of the fixing screw wrench 26 to the angle of handle 25 (α2), but allows free orientation of the geometric axis HA1 of the handle and the geometric axis SA1 of the upper fixing screw wrench. To prevent handle 25 from applying too much force through lateral movement, handle 25 can be biased by a bias spring mechanism S1. This could also be done by a handle that can slide laterally without the bias spring mechanism S1. This substantially decouples all parasitic movements of handle 25 to fixing screw wrench 26 in the direction opposite to the geometric axis SA1. An additional polarization mechanism can also be added to cover the other direction, so that it is perpendicular to the geometric axis HA1.Similarly, handle 29 may have a simple joint SJ1 that allows up and down pivoting movement of handle 29, but it also has a polarizing spring mechanism S2 that allows lateral movements of handle 29 that will be attenuated with less torque to the screw extender 6. In a variant, the simple joint SJ1 may also be implemented as a universal joint. Petition 870250034043, dated 04 / 29 / 2025, p. 19 / 65 11 / 21 similar to UJ1 or UJ2.

[0026] These elements with handles 25, 29 and fixing screw wrench 26 having universal joint UJ1, and possibly UJ2, the orthopedic pedicle screw tightening system, or other type of bone screw tightening system, are entirely mechanical and can be fully integrated into a tool kit. This is also universally applicable to different types of surgical tools where bone anchorage has been made, and can also be used for dental and other applications. It is still possible for the user to apply parasitic torque, but this configuration could greatly reduce this torque, probably by more than 90% compared to the current solution.

[0027] As shown in Figure 3A, different mechanisms are shown which can be added to or implemented in an existing screw extender / screw wrench system, for example, but not limited to, that shown in US patent 10,058,355, which allows reducing any stress on the fixation screw or bone screw that is not specifically directed to the torque that is applied to tighten the bone screw by a torque. Specifically, the stresses that need to be reduced are those in any radial direction (360 degrees) away from a geometric axis of longitudinal extension of screw wrench / screw extender SA1, or HA21, such as the bone screw, see Figures 1 to 3, for example, a monoaxial bone screw or a pedicle screw that is no longer polyaxial, will translate such movements into stress on the bone V.For this purpose, the system in Figure 3 can add flexibility in terms of foldability, which allows for the decoupling of an orientation of the screw wrench element 10 26 that engages firmly with the bone screw head 2, and the parts that will be handled by the surgeon when tightening the screw. Petition 870250034043, dated 04 / 29 / 2025, page 20 / 65 12 / 21 bone. Some of these mechanisms are shown as universal joints UJ1 and UJ2 in specific locations, and some of them as springs S1, S2, to provide a spring-polarized suspension for the handles for the geometric axes HA1, HA2. Another element is the smoothing of the screw extender in an upper area, for example, with slots or openings OS, in an area where the UJ1 of the screw wrench is located, so that the screw extender can be bent together with the screw wrench.

[0028] Of course it would be possible to implement universal joints. UJ as simple as possible, for example, as elastomeric joints without moving parts other than the bendable elastomer, or other types of simplified flexible couplings, for example, double spring couplings. In this sense, the main function of transferring a tightening torque to the bone screw is provided while preserving or substantially preserving the torsional rigidity of the screw wrench 26 and screw extender 6, if present, while simultaneously providing a decoupling between the main axis of the bone screw and the main axis of the tightening elements, which can be implemented with possible equivalents such as universal joints, cardan joints, beam couplings, elastomeric couplings, jaw couplings, etc.

[0029] Figure 3B shows another variant of a handle 290 that can be used to engage and retain the screw extender 6 in a position relative to the pedicle screw 4, to retain the screw extender 6. A portion of screw extender 6 is shown with a side view to the left of Figure 3B. The handle 290 includes a grip portion 292 that is configured to be retained by the hand of a user, operator, or surgeon, a first frame 294 that is fixedly attached to the grip portion 294, a second frame 296 that is suspended along a first linear geometric axis in Petition 870250034043, dated 04 / 29 / 2025, page 21 / 65 13 / 21 in relation to the first frame 294 by elastic elements 272, 274, in the variant shown to the elastic elements 272, 274 which are a pair of springs, second frame 296 guided by a linear guide structure that is located on lateral parts of the first frame 294 and second frame 296, allowing the second frame 296 to slide linearly within a certain range of motion within the first frame 294, polarized by the pairs of elastic elements 272, 274. The linear guide structure can be implemented as complementary guide rails, a linear bearing structure, for example, with a carriage and guide rail, telescopic slider, or sliding surface to reduce friction between the first frame 294 and the second frame 296.Furthermore, the handle 290 additionally includes a central engagement element 298 for engagement with a corresponding engagement structure 32 of the screw extender 6, for example, by having a circular opening with engagement teeth or ridges arranged in a circular manner. The engagement element 298 is elastically polarized with respect to the second frame 296 with two elastic elements, for example, but not limited to, a coil or spring beam 282, 284, so that the engagement element 298 can slide within a certain range of motion relative to the second frame 296 along a second linear geometric axis that is substantially perpendicular to the first linear geometric axis. Furthermore, a linear guide structure, such as, but not limited to, a complementary rail structure, may be provided on the side walls of the engagement element 298 and the side walls of the second frame 296, to guide the linear motion along the second linear geometric axis.

[0030] With the linear suspension of the second frame 296 in relation to the first frame 294 by a first increasing polarization force with springs 272, 274 to a position of the second increasing frame 296 out of a first central or neutral position, and with the Petition 870250034043, dated 04 / 29 / 2025, page 22 / 65 14 / 21 linear suspension of central engagement element 298 in relation to the second frame 296 by a second increasing polarization force with springs 282, 284 to a position of increasing central engagement element 298 outside of a second central or neutral position, wherein the first and second central positions correspond to a central geometric axis location HA2 when the handle 290 is engaging with screw extender 6 in two perpendicularly arranged directions, it is possible to minimize that a user, operator or surgeon pushes the screw extender out of the geometric axis that is defined by the geometric axis HA1 defined by the screw head of the pedicle screw 4, and the extension of the same by the geometric axis HA2 of the screw extender 6 (see Figure 2).

[0031] Additionally, the engagement structure 32 of screw extender 6 and the engagement element 298 of handle 290 are formed in such a way that, by their mutual engagement with each other, for example, by sliding the opening of engagement element 298 of handle 290 towards the engagement structure, they are configured to be freely oriented within a certain angular range between them, but still completely blocking a rotation of the screw extender 6 relative to the handle 290 around the geometric axis HA2. This can be implemented by an engagement structure 32 having a spherical or sphere-like engagement element with engagement ridges or grooves, for example, but without limitation, a hexagonal sphere or torx sphere structure, with at least partially surrounding chamfered edge 34 that limits placement of the handle 290 below the screw extender 6.Edge 34 can be produced from a continuous surrounding structure, or by two or more rotating buttons around the outer cylindrical surface of the screw extender 6. In one variant, it is possible for the central engagement element 298 to have a curved structure while the structure... Petition 870250034043, dated 04 / 29 / 2025, page 23 / 65 The 15 / 21 engagement 32 is cylindrical in shape to allow a certain range of angular movement of the handle 290 relative to the geometric axis HA2. This mechanism between handle 290 and screw extension 6, with engagement structure 32 and central engagement element 298, allows angular tolerance between handle 290 and screw extension 6 to retain pedicle screw 4, and thus is functionally equivalent to a universal joint, but also allows easy removal.

[0032] Figure 3C shows an exemplary embodiment of a rotating handle or knob 250 that can be centrally placed at one end of the screw wrench 20, 26, to tighten a pedicle screw 4. For example, the rotating handle or knob 250 can be rotated around the geometric axis HA2 when in operative connection with the screw wrench 20, 26, by one hand of a user, operator or surgeon, to turn the screw wrench 20, 26 relative to the screw extender 6, while the other hand can retain the screw extender 6 with the handle 290. The handle 250 includes an outer ring or retainer 254 that may have a plurality of rotating knobs or protrusions 253 radially arranged around an outer circumference, or other arrangement to increase a retention friction with a user's hand, and has an inner rectangular opening that accommodates a sliding frame 256.The sliding frame 256 is linearly suspended within the opening by means of two pairs of elastic elements 232, 234 on each side, for example, a coil or a spring beam, along a linear motion range polarized by force along a first geometric axis. The sliding frame 256 can be linearly guided by the opening and frame side walls, for example, with a corresponding rail structure, or another type of linear bearing structure. Furthermore, a central engagement element 258 is located within the sliding frame opening 256. Petition 870250034043, dated 04 / 29 / 2025, page 24 / 65 16 / 21 to rectangular, polarized on each side by an elastic element 242, 244, allowing a range of linear motion along a second geometric axis that is perpendicular to the first geometric axis.

[0033] The central engagement element 258 may have an opening in the form of a rotational torque tool, for example, a hexagonal structure, torx structure or other type of tool engagement structure for applying torque to a wrench 20, 26. For example, the central engagement element may be a non-transverse opening that has a floor that limits an engagement depth with a spherical engagement element 28 of a wrench 20, 26.As shown on the left side of Figure 3C, an upper end of a screw wrench 20, 26 is shown, which has a spherical engagement element 28 for engaging with the central engagement element 258 of the handle or rotary knob 259, for example, but without limitation, a hexagonal ball, hexagonal Torx, or other type of tool that allows a free angular orientation range between the handle 250 and the screw wrench 20, 26, but at the same time allows a torque transmission around the geometric axis HA2 to the screw wrench 20, 26. In this respect, the central engagement element 258 and the spherical engagement element 28 have the functional equivalent of a universal joint, with the possibility of easily removing the handle 259 from the screw wrench 20, 26. It is also possible that the handle 250 is equipped with a torque limiting device, for example, a pin. breakable or a torque ratchet.In one variant, instead of using helix springs 272, 274, 282, 284, 232, 234, 242, 244, it is possible to use other types of elastic elements, for example, but without limitation, elastomeric pads, suspension pistons, elastic cords, spring beam arrangements, plate springs, volute springs, in both a pull and push configuration, providing a force to restore the frames. Repetition 870250034043, dated 04 / 29 / 2025, page 25 / 65. 17 / 21 respective or sliding to a neutral position.

[0034] In a variant shown in Figure 5, a helical tube, or other type of flexible rod, can be used for screw wrench 26, or portions thereof, for example, at locations UJ1 and UJ2. This is another device that allows preserving torsional rigidity around the geometric axis HA2 or SA1, while simultaneously providing bendability off the geometric axis HA2 or SA1. Specifically, a double helical tube can be used, with the two helices opposing each other, providing strong torsional rigidity.

[0035] Next, with regard to Figures 6 to 8, an exemplary device 100 is described that allows measurement and angulation between the geometric axis HA2 of screw extender 6 and screw head 2, and the geometric axis RA2 of rod 7, or determining whether HA2 and RA2 are perpendicular to each other, so that the surgeon or operator can correct an orientation of screw head 2 relative to rod 7 by moving the screw extender 6. This can be done during surgery, when the bone anchor 4 is already fully attached or fixed to the bone of vertebra V, and can therefore be done through the surgical incision, by a device 100 that can be slid over the screw extender 6 in the surgical incision.

[0036] Basically, as shown in Figure 6, device 100 is a hollow tubular element, for example, it has a hollow internal cylindrical cavity that has an internal diameter DIA slightly larger than the external diameter of the screw extender 6, so that device 100 can be slid over the screw extender 6, for example, when none of the handles 25, 29 are attached to the screw extender 6, as shown in Figure 8, where device 100 has been slid over the screw extender 6, and shown in Figure 7 as a cutaway view, which shows device 100 arranged around the screw extender 6, and optionally, the cha Petition 870250034043, dated 04 / 29 / 2025, page 26 / 65 18 / 21 screw ve 20. The tubular device 100 may have other cross-sectional shapes, for example, hexagonal, square, polygonal, etc., provided it is hollow and can be slid over the screw extender 6. On a front face of tubular device 100, the circular front edge includes two protrusions, ridges or edges E1, E2 arranged 180° apart from each other. One protrusion E1 has grooves, is serrated or saw-toothed, or has other types of mechanical irregularities 50 facing from the front face, which may generate a vibration for the tubular device 100 if protrusion E1 is slid and pressed against spinal rod 7, while the other protrusion E2 is smooth, so that no vibration occurs when protrusion E2 is slid and pressed against spinal rod 7.Preferably, viewed from a central geometric axis of tubular device 100 in a radial direction, the protrusion E1 is arranged with grooves 50 in an angular band covering the circular front edge, preferably between 90° and just below 180°, more preferably between 90° and 120°. Additionally, while protrusions E1 and E2 are axisymmetric to each other, rotated 180° relative to each other, the toothed protrusion E1 does not project as far from the front face of the tubular element 100 as the non-toothed protrusion E2, for example, by a difference of distance ΔD. In other words, the protrusion distance D1 of the toothed protrusion E1 is less than the protrusion distance D2 of the non-toothed protrusion E1, for example, by a difference of 1 mm.

[0037] As shown in Figure 8, the operator or surgeon can slide the tubular element 100 over the screw extender 100, for example, after removing or before placing handles 25, 29, and can fully insert the tubular element 100 to ensure that it touches at least one upper surface of the spinal fixation rod 7, at least on one side of the screw head 2. This can be done for a screw extender from an implant kit. Petition 870250034043, dated 04 / 29 / 2025, page 27 / 65 19 / 21 orthopedic as shown exemplarily in Patent No. US10,058,355. After that, the surgeon or operator can rotate the tubular element 100 manually, as indicated by the rotating arrow ROT, for example, with their thumb and index finger pressing the tubular element slightly against the rod 7. In a first case, where the rod 7 is substantially perpendicular to the screw head 2, meaning that the geometric axis HA2 is perpendicular to the geometric axis RA2, which is the desired orientation of the rod 7, the rotation ROT of the tubular element 100 relative to the screw extender 6 will not cause any vibration, since the teeth 50 are arranged slightly recessed, at a distance difference ΔD, and both protrusions E1 and E2 are asymmetrical to each other.

[0038] However, in a second case where rod 7 is not perpendicular to screw head 2, meaning that geometric axis HA2 is not perpendicular to geometric axis RA2, which is an undesirable orientation of rod 7 relative to head 2, manual rotation ROT of the tubular element will cause teeth 50 to engage on a surface of rod 7, causing a vibration and possibly a ratcheting noise that can be manually detected and heard by the surgeon or operator. This will happen as soon as the relative deviation distance of rod 7 on each side of screw head 2 exceeds the distance difference ΔD, which is caused by the oblique angle exceeding a certain threshold.

[0039] With this device 100, it is possible to easily detect, without the need for visual feedback, using a very simple mechanism, the possibility that the rod 7 is not positioned perpendicularly to the screw head 2, and if the surgeon or operator detects the non-perpendicularity, with the screw extender 6, the screw head 2 can be brought to the desired position by the orientation of the screw extender 6 which is attached to the screw head 2, an Petition 870250034043, dated 04 / 29 / 2025, p. 28 / 65 20 / 21 times before the fixing screw 2 is tightened, for example, before the polyaxiality of the pedicle screw 1 is lost or limited.

[0040] Next, with regard to Figures 9-10, an exemplary device 200 is described that allows measurement and angulation between the geometric axis HA2 of screw extender 6 and screw head 2, and the geometric axis RA2 of rod 7, or determining whether HA2 and RA2 are perpendicular to each other, so that the surgeon or operator can correct an orientation of screw head 2 relative to rod 7 by moving the screw extender 6. Compared to device 100, the present device includes electronics and a power supply for actively measuring the distance, by the user, of distance measuring sensors 86, 88, which are arranged on a front face of device 200 or arranged so that they can measure a distance from the respective sensor 86, 88 to the spinal rod 7, on each side of the screw head 2 of the pedicle screw 1.The sensors 86 and 88 can be implemented, by way of example, but without limitation, as optical, acoustic, ultrasonic, capacitive, or inductive distance measuring sensors. Figure 9 illustrates the device 200, which is placed on the screw extender 6, showing, on the left side, the rod 7 perpendicularly positioned to the screw head 2 (the desired position), and on the right side, the rod 7 not perpendicularly positioned to the screw head 2. The sensors 88 and 86 can measure a distance D11 and D12 on each side of the screw head 2 to determine if the distances are equal, to see if perpendicularity is present.The signals from sensors 86, 88 can be processed by a microcontroller that is powered by a battery, and a result of the comparison of the measured distances D11 and D12 can be indicated to the user, for example, by optical, acoustic, haptic or vibratory means, for example, by means of two lights 82 that can show. Petition 870250034043, dated 04 / 29 / 2025, page 29 / 65 21 / 21 perpendicularity, for example, with a green light, or non-perpendicularity, with a red light, for example, LED 82. In a variant, the signal can be acoustic, for example, with speaker 84 which indicates a low acoustic frequency signal for perpendicularity, and a high acoustic frequency signal for non-perpendicularity.

[0041] In relation to Figure 10, another variant is shown, in which the detection sensors 94, 96 having a semicircular contact surface are arranged on each half of the front circular surface of the device 200. In addition, the device 200 has an arrow, line or other impression or indication 93 that shows the desired rotation position of the device 200 once placed in the screw extender 6, so that the device 200 can be approximately aligned to a geometric axis of longitudinal extension of the rod 7, for example, along the incision which is generally substantially parallel to the rod. The orientation indicator can also be implemented with small rotating buttons, projections or protrusions 91, 92 to show the orientation of the device 200.The front surfaces of the detection sensors 94, 96 can detect, come into contact with, or be in proximity to the rod 7 on each side of the screw head 2, for example, by sensors 94, 96 arranged as buttons that can be pressed or, for example, by a capacitive measurement to detect proximity to the rod 7.

[0042] Although the invention has been disclosed with reference to certain preferred embodiments, various modifications, alterations and changes to the described embodiments, and equivalents thereof, are possible without departing from the sphere and scope of the invention. Consequently, it is intended that the invention is not limited to the described embodiments, and that the broadest reasonably wide interpretation is given in accordance with the language of the appended claims. Petition 870250034043, dated 04 / 29 / 2025, p. 30 / 65

Claims

1 / 3 CLAIMS 1. Bone screw tightening device comprising: a screw wrench (26), wherein the screwdriver (26) includes, along a geometric axis of longitudinal extension, at least one device (UJ1, UJ2) for providing radial bendability and, at the same time, preserving torsional rigidity along a geometric axis of longitudinal extension of the bone screw (1), characterized in that the bone screw tightening device further includes a screw extender (6) for removable attachment to a screw head (2) of the bone screw (1) and for retaining the bone screw (1) and accommodating the screw wrench (26), and wherein the at least one device (UJ1, UJ2) for providing radial bendability is located along the screw wrench (26) and located within the screw extender (6) when the screw extender (6) is attached to the screw head (2) of the bone screw (1),or in an upper section (8) of the screw wrench (26) outside the screw extender (6) when the screw extender (6) is attached to the screw head (2) of the bone screw (1)., 2. Bone screw tightening device according to claim 1, characterized in that at least one device (UJ1, UJ2) includes a universal joint or a double helix tube.

3. Bone screw tightening device, according to claim 1, characterized in that it further comprises: a first handle (29, 290) for retaining the screw extender (6); and a second handle (25, 250) for engaging with the screw wrench (26), Petition 870250034043, dated 29 / 04 / 2025, page 31 / 65 2 / 3 wherein the first handle (29, 290) includes a first suspension mechanism (S2) to provide a suspension between the first handle (29, 290) and the screw extender (6), and wherein the second handle (25, 250) includes a second suspension mechanism (S1) to provide a suspension between the second handle (25, 250) and the screw wrench (26).

4. Bone screw tightening device, according to claim 3, characterized in that the first handle (29, 290) includes a universal joint mechanism between an area configured to be retained by a user, and an attachment point for the screw extender (6), and in that the device (UJ2) for providing radial bendability is located between the second handle (25, 250) and the upper section of the screw wrench (26).

5. Bone screw tightening device, according to claim 1, characterized in that the screw extender (6) includes an element that provides lateral smoothness (OS) to increase the bendability of the screw extender (6) in a weakened area (OS).

6. Bone screw tightening device, according to claim 5, characterized in that the element is arranged adjacent to at least one device (UJ1) to provide radial bendability.

7. Bone screw tightening device, according to claim 1, characterized in that a first device (UJ1) for providing radial bendability is located along the screw wrench (26) when the screw extender (6) is attached to the screw head (2) of the bone screw (1), and a second device (UJ2) for providing radial bendability is located in an upper section (8) of the screw wrench (26) outside the screw extender (6) when the screw extender (6) is attached to the screw head (2) of the bone screw (1).

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