Augmented reality guidance system for guiding surgical procedures on a joint portion of a bone

Description

Technical field

[0001] The present invention relates to the technical sector of orthopedic surgery, and more particularly concerns an augmented reality guidance system for a surgical operation on a part of a bone joint.

[0002] The invention finds an application to assist in the installation of any type of orthopedic joint implant such as knee, shoulder, hip prostheses and, more generally, any type of orthopedic implant requiring cutting or drilling at the level of the anatomical bone area to be prosthetized. Prior art

[0003] It is perfectly known to a person skilled in the art to use different devices, commonly called placement ancillaries for the placement of different orthopedic implants. For example, the devices may consist of tibial guide blocks, femoral guide blocks, etc. These blocks incorporate slots and holes in their thickness for the passage and guidance of instruments with cutting blades or drilling drills, which slots or holes are suitably oriented and positioned according to the bone cuts or drilling that must be made for the placement of the implant.

[0004] It is also known that these guide blocks comprise at least one bearing face on the articulation part, custom-designed from a previously established virtual model.

[0005] In this way, during the intervention, the surgeon positions the custom-made guide on the bone, which guide must theoretically cooperate in a unique position and orientation with the part of the bone, in order to be able to optimally guide the cutting or drilling operations carried out by the surgeon.

[0006] However, in practice, the precise positioning of this custom guide remains delicate.

[0007] Document FR 3 078 624 has already proposed to try to remedy this drawback by proposing an augmented reality assistance system for the positioning of specific surgical instruments.

[0008] According to this document the system includes: a guide block intended to be fixed on the articulation part of the bone and comprising, on the one hand, at least one bearing face on the bone, custom-designed from a virtual bone model and, on the other hand, a three-dimensional visual reference; a camera intended to visualize and follow the reference; a processing system configured to process data from the virtual bone model and in real time image data from the camera to determine the position and orientation of the guide block, so as to display on the display attached to the camera, and superimposed on the field of vision of a user, a three-dimensional virtual representation of at least one geometric data relating to the bone model, the position and orientation of which are determined by those of the guide block.

[0009] In other words, according to this document, it is possible to visualize a mechanical axis or bone contours superimposed on real images of the guide block.

[0010] This helps the surgeon during the operation to correctly position the guide block. In practice, the surgeon uses virtual representations of the bone's mechanical axis and contours, for example of the epiphysis, to correctly position the guide block, by matching and superimposing said virtual representations on the real bone.

[0011] This technique is interesting, but relies on the surgeon's ability to match virtual information with real information, which can lead to a risk of error.

[0012] Indeed, during surgery on a bone joint, only the joint itself is visible to the surgeon. The other parts of the limb that include the joint are hidden by the surgical field, and the joint itself is stained with blood, and possibly covered with fat, which complicates the operation.

[0013] Furthermore, and importantly, when the virtual bone model is obtained using techniques such as CT scanning, for example, these techniques do not take into account the cartilage of the bone. MRI can take this cartilage into account, but this technique is restrictive for the patient, expensive, and has relatively long waiting times.

[0014] In this way, the virtual bone model on which the guide is custom-designed is incorrect. The guide block was custom-designed to fit a bone that does not contain cartilage.

[0015] It follows that when the surgeon attempts to position the guide block on the part of the joint to be operated on, the cartilage will create an excess thickness which will shift the cutting planes and drilling axes planned and positioned by the guide block.

[0016] Thus, in addition to the difficulty in finding the correct positioning of the custom guide, which therefore no longer adapts very precisely to the bone, this also results in inaccuracies in the positioning of the different cutting planes and drilling axes.

[0017] To remedy this problem, the surgeon may decide to remove the cartilage, but this solution is not optimal since the removal of the cartilage cannot be perfectly controlled.

[0018] Another solution is to create a custom-made guide that rests on bone areas where there is no cartilage. However, this technique has the disadvantage of providing very bulky guides, and therefore a more invasive operation with an increased risk of infection.

[0019] Also known is document WO2019 / 141704, which describes an augmented reality guidance system for a surgical operation on a part of a bone joint. However, this document remains silent on the difficulties that the presence of cartilage represents for correctly positioning the tracking elements. WO2019 / 141704 describes the presence of two tracking elements, fixed to the bone. WO2019 / 141704 therefore involves making an additional incision and providing an additional anchor to fix the second tracking element, which presents disadvantages for the patient. Statement of the invention

[0020] One of the aims of the invention is to provide a system for guiding the various cutting or drilling operations of a bone joint, the precision of which is optimal, while remaining simple, quick to implement, with a limited risk of infection.

[0021] For this purpose, an augmented reality guidance system for a surgical operation on a part of a bone joint has been developed, the system comprising: a tracking element intended to be fixed on the articulation part of the bone, the tracking element comprising, on the one hand, at least one bearing face on the articulation part custom-designed from a virtual model of the articulation part of the bone and, on the other hand, a three-dimensional visual reference mark; a camera intended to visualize and follow the reference mark; a processing system configured to process data from the virtual bone model and in real time image data from the camera to determine the position and orientation of the tracking element, so as to display on a display attached to the camera, and superimposed on the field of vision of a user, a three-dimensional virtual representation of at least one geometric data item relating to the bone model, the position and orientation of which are determined by the position and orientation of the tracking element.

[0022] According to the invention, the guidance system comprises a probe also equipped with a three-dimensional visual reference mark and intended to palpate at least three zones of a part of the bone, outside the cartilaginous zone. The reference mark of the probe is also intended to be tracked by the camera, and the processing system is further configured to determine the position and orientation of the probe relative to the position and orientation of the tracking element, so as to correct on the display and after palpation, the position and orientation of the three-dimensional virtual representation of the geometric data relating to the bone model relative to the tracking element.

[0023] In this way, the invention makes it possible to position a tracking element on the articulation part of the bone, the position of which is known and located with optimal precision.

[0024] In fact, the invention does not necessarily serve to directly position a guide block, but simply a tracking element which carries a reference mark and whose position relative to the virtual bone model is precisely known.

[0025] Thus, during the intervention, the surgeon places the tracking element on the bone, with the imprecision linked to the cartilage. The surgeon then takes the feeler equipped with a marker, and comes to feel areas, for example at least three areas of the bone, outside the cartilaginous area. This operation will allow, by matching the felt areas, and those of the virtual bone model, to precisely realign the position and orientation of the virtual representation of the geometric data relating to the virtual model in relation to the real position of the bone.

[0026] The geometric data relating to the bone model virtually represented and displayed on the display can be of any type, such as a geometric surface or contours of the bone model, a mechanical axis, planned cutting planes or drilling axes, etc.

[0027] The palpation technique, also known by the English expression " bone morphing » is carried out here only on three areas, and therefore without the overly invasive nature, or the known risk of infection for this technique.

[0028] Indeed, unlike the technique du « bone morphing » of the prior art, it is not necessary to fix pins on the bone concerned with incisions which are not justified by the surgical procedure. The risk of infection is therefore not increased, and the intervention time is not extended.

[0029] The present invention therefore makes it possible to fix a marker on the articulation part, the position of which is precisely known, which position has been specifically realigned in relation to the actual position of the bone.

[0030] This makes it possible to assist the use of other objects, such as guide blocks or instruments, themselves identified, whose relative position in relation to the tracking element and therefore in relation to the displayed virtual representation of the geometric data relating to the bone model, which itself will be perfectly positioned in relation to the real bone, will be known.

[0031] For this purpose, the system comprises for example a cutting or drilling instrument equipped with a three-dimensional visual reference, the reference of the instrument is also intended to be tracked by the camera, and the processing system is further configured to determine the position and orientation of the instrument relative to the position and orientation of the tracking element, so as to display on the display the position and orientation of a cutting plane or drilling axis linked to the instrument relative to the tracking element.

[0032] Several embodiments of the display can be envisaged without departing from the scope of the invention.

[0033] For example, the display may be a screen displaying the images from the camera, or may be in the form of at least one pair of glasses, which glasses may carry the camera, and are intended to be worn by the user, the display only displaying the virtual representations.

[0034] Advantageously, the geometric data relating to the bone model corresponds to the external surface of said virtual bone model, the processing system is further configured to, after correction, process the data of the virtual bone model in order to increase its dimensions at the level of the support surface of the tracking element so that the display represents the support face of the tracking element in contact with the external surface of the virtual bone model.

[0035] According to one embodiment, the tracking element comprises means for fixing a guide block, or else comprises at least one guide orifice for a fixing pin to the bone, and a guide block having at least one orifice for the pin to pass through, the guide block being intended to be fixed to the bone in a determined position and orientation and guided by the pin. By guide block is meant a block which comprises at least one slot or at least one orifice to form at least one cutting or drilling guide.

[0036] Advantageously, the guide block comprises at least one slot and / or at least one guide orifice whose position and / or orientation are adjustable relative to the body of the guide block.

[0037] Preferably, and in order to facilitate the surgical operation, the visual marker is fixed on the tracking element in a removable or breakable manner. Thus, when the tracking element has made it possible to correctly position a guide block, or directly cutting or drilling instruments, the marker on the tracking element can be broken or removed so as not to hinder the cutting or drilling operations as such. Description of the figures

[0038] Other characteristics and advantages of the invention will emerge clearly from the description given below, for information purposes only and in no way limiting, with reference to the appended figures in which: [ Fig. 1 ] there figure 1 is a schematic representation illustrating in perspective a tracking element of the system according to the invention, positioned on a part of an articulation of a femur. Fig. 2 ] there figure 2 is a schematic representation illustrating the display, the processing system and the camera of the augmented reality guidance system of the invention. Fig. 3 ] there figure 3 is a schematic representation illustrating in perspective a tracking element of the system according to the invention, positioned on a part of an articulation of a femur on the hip side. Fig. 4 ] there figure 4 is a schematic representation illustrating in perspective a tracking element of the system according to the invention, positioned on a part of the articulation of a humerus on the shoulder side. Fig. 5 ] there figure 5 is a schematic representation illustrating in perspective a tracking element of the system according to the invention, positioned on a part of a shoulder blade articulation. Fig. 6 ] there figure 6 is a schematic representation illustrating in perspective a tracking element of the system according to the invention, positioned on a part of a tibia joint on the knee side. Fig. 7 ] there figure 7 is a schematic representation illustrating in perspective a guide block fixed on a tibia and comprising a guide slot whose position and / or orientation are adjustable relative to the guide block. Fig. 8 ] there figure 8 is a schematic representation illustrating in perspective a probe equipped with a second three-dimensional visual reference. Fig. 9 ] there figure 9 is a schematic representation illustrating in perspective an instrument, such as a drill, equipped with a three-dimensional visual reference. Detailed description of the invention

[0039] In reference to the figures 1 à 9 , the invention relates to an augmented reality guidance system for a surgical operation of a joint part (1) of a bone.

[0040] The invention is not limited to a particular joint, and makes it possible to guide the placement, i.e. the making of bone cuts or drilling, of any type of orthopedic joint implant, such as knee, shoulder, hip, etc. prosthesis.

[0041] In a known manner, the guidance system comprises a tracking element (2) intended to be fixed on an articulation part (1) of a bone. The tracking element (2) comprises at least one bearing face (21) on the articulation part, custom-designed from a virtual bone model.

[0042] This makes it possible to create a unique relationship between the virtual bone model and the tracking element (2) so that, if we know the position and orientation in space of the tracking element (2), we therefore know very precisely the position and orientation in space of the virtual bone model.

[0043] In order to be able to know the position and orientation in space of the tracking element (2), the latter comprises, and in a known manner, a three-dimensional visual reference (22) integrating information relating to the position and orientation of the tracking element (2), capable of being processed by a processing system (3), in particular a computer system.

[0044] Still in a known manner, the augmented reality system comprises a camera (4) intended to visualize and follow the three-dimensional visual reference (22) of the tracking element (2), and a processing system (3) configured to process data from the virtual bone model and in real time image data from the camera (4) to determine the position and orientation of the tracking element (2).

[0045] In a manner known to those skilled in the art, the camera (4) is subject, in particular in terms of reference, to a display (6) making it possible to display information transmitted by the processing system (3) superimposed on the field of vision of a user.

[0046] The display (6) is for example in the form of a screen allowing the images from the camera (4) to be viewed directly and the information transmitted by the processing system (3) to be superimposed on them, or else is in the form of augmented reality glasses, i.e. glasses comprising at least one lens forming the display (6) and through which the user can observe a scene, and superimposed on which the display (6) displays the information.

[0047] In this latter embodiment, and in a known manner, the augmented reality glasses can also carry the camera (4).

[0048] In this way, when the processing system (3) detects that the camera (4) is viewing the three-dimensional visual reference (22) of the tracking element (2), the processing system (3) displays on the display (6) a three-dimensional virtual representation of at least one geometric data item relating to the bone model positioned relatively to the tracking element (2). In other words, the virtual representation of the geometric data item is attached to the tracking element (2), according to a single position and orientation which depends in particular on those of said tracking element (2).

[0049] The geometric data relating to the bone model virtually represented and displayed on the display (6) can be of any type, such as a geometric surface or contours of the bone model, a mechanical axis, planned cutting planes or drilling axes, etc.

[0050] The augmented reality system is well known in the state of the art and will not be described in more detail. The invention consists in particular in correcting the imprecision of this system, inherent in the presence of cartilage or fatty matter on the part of the joint on which the tracking element (2) must be fixed.

[0051] To do this, the system according to the invention comprises a probe (7) also equipped with a three-dimensional visual marker (71) carrying information relating to the position and orientation of the probe (7) in space.

[0052] When the tracking element (2) is fixed to the real bone, the display (6) will virtually represent the geometric data relating to the bone model superimposed on the real scene. However, given the presence of cartilage, there will be a slight shift between the real image of the bone and the virtual representation. Indeed, and in practice, the tracking element (2) is not in direct contact with the bone, but in contact with an excess thickness of cartilage.

[0053] To correct this shift, the surgeon will palpate, with the located feeler (7), at least three zones, for example three zones of approximately 2 mm 2< and non-cartilaginous.

[0054] Since the processing system (3) accurately determines the position and orientation of the elements attached to the markers (22, 71), the position and orientation in space of the probe (7) relative to the position and orientation of the tracking element (2) is known.

[0055] In theory, the three zones that the probe (7) comes to feel must normally be zones corresponding to equivalent zones of the virtual bone model. The processing system (3) is configured to rectify this offset and very precisely reposition the virtual bone model, and in particular the virtual representation of the geometric data, in relation to the three-dimensional visual reference (22) of the tracking element (2), and therefore in relation to the tracking element (2) itself.

[0056] From the above, this allows to know very precisely the position of the articulation part of the bone, and to visualize it in three dimensions and virtually on the display (6) superimposed on the real bone. It is also possible to visualize the mechanical axis of the bone, or the cutting planes or planned drilling axes.

[0057] To then facilitate and guide the surgical operation, the system according to the invention also comprises an instrument (8), such as a cutting or drilling instrument, which also comprises a three-dimensional visual marker (81) carrying information relating to the position and orientation of said instrument (8) in the space that the treatment system (3) is able to process when viewed by the camera (4).

[0058] In other words, it is possible to know precisely the position and orientation of the instrument (8) in relation to the visual reference (22) of the tracking element (2), and therefore in relation to the bone itself. The information integrated into the three-dimensional visual reference (81) of the instrument (8) allows the processing system (3) to display on the display (6) and superimposed on the surgeon's field of vision, for example, a drilling axis or a cutting plane linked to the instrument (8) and perfectly positioned in relation to the real bone, without the imprecision relating to the excess cartilage thickness.

[0059] The tracking element (2) may also comprise means for fixing a guide block (9), in particular in a position and orientation known and determined relative to the tracking element (2).

[0060] In this configuration, the three-dimensional visual cue (22) of the tracking element (2) may be connected to the tracking element (2) in a removable or breakable manner allowing the surgeon to remove it so as not to interfere with the subsequent drilling cutting operation.

[0061] According to another embodiment, the tracking element (2) comprises at least one, and preferably two holes (10) adapted to receive two pins (11) intended to be fixed in the bone. The tracking element (2) can then be removed by sliding it along the pins (11), and a guide block (9) also comprising two same holes (91) can be fixed to the bone by positioning it via the two pins (11), see figure 7 The guide block (9) comprises a slot (92) and / or guide hole whose position and orientation are known relative to the bone.

[0062] In order to be able to adapt to the needs of the surgeon, the position and / or orientation of the slots (92) or guide orifice are adjustable relative to the guide block (9).

[0063] For example, in reference to the figure 7 , the guide block (9) comprises a main part (93) intended to be fixed to the bone by the fixing pins (11), and a guide slot (92) formed in a secondary part (94) of the block, connected to the main part by a ball joint (95). Clamping means (96), for example by screwing, are subject to the ball joint (95) to block its pivoting. The secondary part (94) of the guide block (9) comprises a three-dimensional visual marker (97) carrying information relating to the position and orientation of the slot (92) in the space that the treatment system (3) is able to treat when it is viewed by the camera (4).

[0064] In other words, it is possible to know precisely the position and orientation of the slot (92) relative to the visual reference (22) of the tracking element (2), and therefore relative to the bone itself. The information integrated into the three-dimensional visual reference (97) of the secondary part (94) of the guide block (9) allows the processing system (3) to display on the display (6) and superimposed on the surgeon's field of vision for example, a cutting plane or drilling axis linked to the secondary part (94) of the guide block (9) and perfectly positioned relative to the real bone, without the imprecision relating to the excess cartilage thickness.

Claims

1. A guidance system in augmented reality for a surgical operation of a joint part (1) of a bone, the system comprising: - a tracking element (2) intended to be fixed on the joint part of the bone, the tracking element (2) comprising, on one hand, at least one support face (21) on the joint part custom-designed from a virtual model of the joint part of the bone and, on the other hand, a three-dimensional visual marker (22); - a camera (4) intended to visualize and track the marker (22); - a processing system (3) configured to process data from the virtual bone model and realtime image data from the camera (4) to determine the position and orientation of the tracking element (2), so as to display on a display (6) attached to the camera (4), and superimposed on the user's field of vision, a three-dimensional virtual representation of at least one geometric data related to the bone model, whose position and orientation are determined by the position and orientation of the tracking element (2); - a probe (7) also equipped with a three-dimensional visual marker (71) and intended to probe at least three areas of a part of the bone outside the cartilage zone, the marker (71) of the probe (7) is also intended to be tracked by the camera (4), characterized in that the processing system (3) is further configured to determine the position and orientation of the probe (7) relative to the position and orientation of the tracking element (2), so as to correct on the display (6) and after probing, the position and orientation of the three-dimensional virtual representation of the geometric data related to the bone model relative to the tracking element (2).

2. The guidance system according to claim 1, characterized in that it comprises a cutting or drilling instrument (8) equipped with a three-dimensional visual marker (81), the marker (81) is intended to be tracked by the camera (4), and the processing system (3) is further configured to determine the position and orientation of the instrument (8) relative to the position and orientation of the tracking element (2), so as to display on the display (6) the position and orientation of a cutting plane or drilling axis related to the instrument (8) relative to the tracking element (2).

3. The guidance system according to claim 1, characterized in that the display (6) is a screen displaying images from the camera (4).

4. The guidance system according to claim 1, characterized in that the display (6) is at least one lens of glasses intended to be worn by the user.

5. The guidance system according to claim 4, characterized in that the glasses carry the camera (4).

6. The guidance system according to claim 1, characterized in that the geometric data related to the bone model corresponds to the external surface of said virtual bone model, and the processing system (3) is further configured to, after correction, process the data of the virtual bone model in order to increase its dimensions at the support face (21) of the tracking element (2) so that the display (6) represents the support face (21) of the tracking element (2) in contact with the external surface of the virtual bone model.

7. The guidance system according to claim 1, characterized in that the visual marker (22) is fixed on the tracking element (2) in a removable or breakable manner.

8. The guidance system according to claim 1, characterized in that the tracking element (2) comprises means for fixing a guidance block (9).

9. The guidance system according to claim 1, characterized in that the tracking element (2) comprises at least one guiding orifice (10) for a pin (11) to be fixed to the bone, and the system comprises a guidance block (9) having at least one orifice (91) for the passage of the pin (11), the guidance block (9) being intended to be fixed to the bone in a determined position and orientation guided by the pin (11).

10. The guidance system according to claims 8 to 9, characterized in that the guidance block (9) comprises at least one slot (92) and / or at least one guiding orifice whose position and / or orientation are adjustable relative to the guidance block (9)