Tracker device

Abstract

To provide a tracker apparatus that causes little invasion to a patient, has excellent safety, can be firmly fixed to a pelvis of the patient, can be easily removed after a surgical operation, and causes little invasion remaining in skin or bone after removal.SOLUTION: A tracker apparatus constituting a navigation system used when performing an orthopedic surgical operation comprises: a tracker unit (110) having optical markers (111) to (114); and a fixing member (120) for fixing the tracker unit (110) to a pelvis of a patient, wherein the fixing member (120) includes a helical coil having a pointed end portion (121).SELECTED DRAWING: Figure 1A

Description

[[Technical Field]]

[0001] The present invention relates to a tracker device that constitutes a navigation system or a robot system used in performing orthopedic surgery, and particularly relates to a bone tracker device. [[Background Art]]

[0002] Conventionally, for example, in total hip arthroplasty, navigation systems and robot systems have been proposed that support guiding and inserting an acetabular cup into an ideal position and orientation when placing the acetabular cup in a patient's acetabulum (see Patent Document 1 below).

[0003] The aforementioned navigation system comprises a stereo camera provided with a near-infrared light emitting unit, a pelvic tracker unit fixed to the patient's pelvis, a registration tracker unit arranged at a marker point or reference position on the pelvis, a tracker unit connected to an acetabular cutting tool, and a femoral tracker unit connected to the patient's femur.

[0004] Each of these tracker units is provided with a plurality of or a single reflective marker or self-luminous marker. By capturing images of these tracker units with a stereo camera and measuring the position of each individual tracker based on the principle of triangulation, the relative positional relationship between the tracker units can be obtained.

[0005] After the positional relationship determined in this way is registered in a computing device, by continuously measuring (tracking) the positional relationship between the pelvic tracker unit and the tracker unit connected to the acetabular cutting tool, changes in the relative position of the acetabular insertion tool with respect to the patient's pelvis (changes caused by body movement and / or movement of the tool) can be grasped. As a result, in total hip arthroplasty, an implant called an acetabular cup can be placed at an accurate pelvic position with a desired abduction angle and anteversion angle. [[Prior Art Documents]] [[Patent Documents]]

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-508549 [Overview of the project] [Problems that the invention aims to solve]

[0007] Pelvic tracker units with markers are typically fixed to the patient's pelvis using bone screws (pins or bone screws) as fixing members. The specific procedure involves first drilling a pilot hole through the skin incision into a part of the pelvis called the iliac crest using an electric drill, and then inserting a bone screw while self-tapping it.

[0008] However, in a structure where the marker unit and the bone tracker unit are separate, the fixing member consisting of a bone screw to which the tracker unit is attached does not always have sufficient resistance to being pulled out when it is implanted in the pelvis (spongy portion). This can lead to problems such as the tracker unit becoming loose or the screw loosening, resulting in poor positional accuracy. Such loosening is especially likely to occur when the patient's position is changed during surgery, and this is the most troublesome issue for applications that require high precision and accuracy in implant placement. Furthermore, since pins or bone screws with an outer diameter of 4-6 mm or more are typically inserted through incisions several millimeters larger than the implant site, postoperatively, scars (suture marks) remain on the skin in addition to the incisions made for implant placement. Additionally, holes remain in the pelvis after the bone screws are removed, and it takes time for them to close.

[0009] Furthermore, this type of fixation method can be extremely invasive to the patient and potentially dangerous. When drilling pilot holes with an electric drill, if the direction of the electric drill deviates, it can damage the pelvis or blood vessels. Cases of damage to the bone have been reported (H. Kan, I. Nusem / Arthroplasty Today 19(2023)101070). Therefore, increasing the number of bone screws or increasing their diameter has limitations from the standpoint of patient safety.

[0010] This invention was made based on the circumstances described above. The objective of the present invention is to provide a tracker device that is minimally invasive to the patient, highly safe, can be firmly fixed to the patient's pelvis, can be easily removed after surgery, leaves small scars on the skin after removal, and causes minimal damage to the bone. [Means for solving the problem]

[0011] The tracker device of the present invention is a tracker device that constitutes a navigation system used when performing orthopedic surgery, and comprises a tracker unit having at least one optical marker and a fixing member for fixing the tracker unit to the patient's bone, wherein the fixing member is made of a helical coil having a pointed end.

[0012] In the tracker device of the present invention, it is preferable that the helical coil is formed from a wire having a circular cross-section, with a wire diameter (d) of 1.2 to 3.0 mm, a coil diameter (D) of 2.8 to 12 mm, a coil pitch (p) of 2.4 to 30 mm, and a coil length (L) of 8 to 140 mm. In this case, it is particularly preferable that the ratio of the coil diameter to the wire diameter (D / d) is 1.5 to 5, and the coil pitch (p / d) to the wire diameter is 1.35 to 6.

[0013] In the tracker device of the present invention, it is preferable that the helical coil is formed from a wire having a polygonal cross-section such as a circle, semicircle, ellipse, triangle, quadrilateral (square, rhombus, rectangle, trapezoid, etc.), pentagon, or hexagon. Furthermore, these wires tend to twist around their central axis when formed into a helical coil. This twisting can widen the entry point and penetration path when screwing the coil into the bone, potentially loosening the helical coil's fixation to the pelvis or other bones. Therefore, circular or polygonal wires are preferable.

[0014] In the tracker device of the present invention, if the tip of the helical coil is machined with a cutting edge, it is preferable that there is no need to drill a guide hole with a drill when penetrating the cortical bone on the bone surface.

[0015] Furthermore, it is preferable that the fixing member be detachably attached to the tracker unit. Furthermore, it is preferable that the tracker unit has at least one light-reflecting marker or light-emitting marker. Furthermore, the tracker unit may have a two-dimensional tracker on which optically readable information (image information such as a two-dimensional matrix) is printed.

[0016] The tracker device of the present invention is suitably used for fixation to the patient's bone during artificial joint replacement surgery. For example, it is suitably used to fix the device to the patient's pelvis or femur when performing total hip replacement surgery. Furthermore, it is suitably used for fixation to the patient's femur or tibia when performing total knee replacement surgery. Furthermore, it is also suitably used to fix the device to the necessary bone in the patient when performing other artificial joint replacement surgeries (for example, shoulder joint replacement). However, this tracker device is not limited to use in artificial joint replacement surgery; it can also be used in other surgeries requiring precise navigation (for example, pelvic fracture repair). [Effects of the Invention]

[0017] According to the tracker device of the present invention, since the fixing member is constituted by a helical coil having a pointed end (preferably sharp cutting edge processing), attachment and detachment operations to and from a patient's bone (pelvis) can be easily performed. Furthermore, the attachment operation of the tracker device can be performed only by hand without using an electric drill or the like, and the depth can be adjusted slowly, so that the device is also excellent in safety. Furthermore, the attached tracker device of the present invention is firmly fixed to the bone, and has extremely high resistance to pulling out and loosening. Removal can also be performed only by hand.

[0018] Furthermore, the scar remaining on the skin after removing the tracker device of the present invention is caused by the piercing of the wire of the helical coil (a hole corresponding to the diameter of the wire), which is significantly smaller than a scar when a pin or a bone screw is used, and in most cases, does not require suture. Furthermore, since the amount of bone tissue displaced when embedding the helical coil into the bone is small, the hole remaining in the bone after removing the fixing member (helical coil) is also small. And the invasiveness to the patient caused by using the tracker device of the present invention is extremely low. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [Figure 1A] It is a front view showing the tracker device according to the first embodiment of the present invention. [Figure 1B] It is a side view showing the tracker device according to the first embodiment. [Figure 1C] It is a cross-sectional view of a fixing member constituting the tracker device according to the first embodiment. [Figure 2A] It is a front view showing the tracker device according to the second embodiment of the present invention. [Figure 2B] It is a cross-sectional view of a fixing member constituting the tracker device according to the second embodiment. [Figure 3] It is a front view showing the tracker device according to the third embodiment of the present invention. [Figure 4] It is a front view showing the tracker device according to the fourth embodiment of the present invention. MODE FOR CARRYING OUT THE INVENTION

[0020] <First Embodiment> The tracker device 100 of this embodiment, shown in Figures 1A to 1C, is a tracker device that constitutes a navigation system used when performing total hip replacement surgery and is fixed to the patient's pelvis.

[0021] This tracker device 100 comprises a tracker unit 110 and a fixing member 120. During total hip replacement surgery, the tracker unit 110 is positioned outside the patient's body, and the fixation member 120 has its distal end implanted in the pelvis and its proximal end located outside the body.

[0022] The tracker unit 110, which constitutes the tracker device 100, has four reflective markers (tracking targets) 111 to 114, which are made of near-infrared reflective ball markers.

[0023] A fixing member 120 is detachably attached to the distal end of the tracker unit 110. The mechanism for attaching and detaching the fixing member 120 is not particularly limited, and a locking mechanism such as a screw can be exemplified. The fixing member 120 that constitutes the tracker device 100 is made of a helical coil having a pointed end 121.

[0024] The fixing member 120, which consists of a helical coil, is formed from a wire (round wire) having a circular cross-section, and the tip 121 of the fixing member 120 is approximately conical or approximately frustoconical (the apex of the frustoconical may be rounded).

[0025] Examples of materials used for the fixing member 120 include metal members such as stainless steel, Ni-Ti alloy, Co-Cr alloy, and tantalum, or members coated with a low-friction resin.

[0026] The diameter d of the wire forming the fixing member 120 is usually preferably 1.2 to 3.0 mm, and more preferably 1.8 to 2.5 mm. If the wire diameter d is too small, it becomes difficult to form a fixing member with high pull-out strength. On the other hand, if the wire diameter d is too large, the objectives of the present invention, which are to be minimally invasive and minimize scarring, cannot be fully achieved.

[0027] The outer diameter (coil diameter) D of the fixing member 120 is usually preferably 2.8 to 12 mm, and more preferably 5 to 10 mm.

[0028] Here, the ratio of the coil diameter D to the wire diameter d (D / d) is preferably 1.5 to 5. Fixing members with an insufficient ratio (D / d) cannot exhibit sufficient pull-out strength. On the other hand, fixing members with an excessive ratio (D / d) become difficult to implant into the bone (attaching the tracker device) and difficult to remove from the bone (removing the tracker device).

[0029] The pitch (coil pitch) p of the fixing member 120 is preferably 2.4 to 30 mm.

[0030] The ratio of the coil pitch p to the wire diameter d (p / d) should preferably be between 1.35 and 6. A fixing member with an insufficient p / d ratio (tightly wound) cannot fully achieve the goal of minimal invasiveness. On the other hand, a fixing member with an excessive p / d ratio (loosely wound) cannot exhibit sufficient pull-out strength.

[0031] The length (coil length) L of the fixing member 120 is preferably 8 to 140 mm from the viewpoint of ensuring sufficient pull-out resistance.

[0032] Prior to performing artificial hip replacement surgery, the tracker device 100 of this embodiment is attached to the patient's pelvis. The specific procedure involves bringing the tip 121 of the fixing member 120 into contact with the patient's skin covering the pelvis (the attachment site of the device), and rotating the fixing member 120 around its axis in this example to the right (clockwise) to introduce it into the body and bring the tip 121 to the pelvis. If necessary, the tip is positioned perpendicular to the cortical bone and twisted to penetrate it, and then the rotation is continued in the direction of its original spiral shape to advance the fixing member 120 spirally and embed it in the pelvis. This allows the tracker device 100 to be attached to the patient's pelvis.

[0033] Here, the procedure for implanting the fixing member 120 for attaching the tracker device 100 into the pelvis may be performed with the tracker unit 110 attached to the fixing member 120. Alternatively, the fixing member 120 may be removed from the tracker unit 110, the removed fixing member 120 may be implanted into the pelvis using a jig such as a T-shaped handle, and then the tracker unit 110 may be attached to the proximal end of the fixing member 120 that extends from the skin.

[0034] The reflective markers 111 to 114 provided on the tracker unit 110 can be photographed (recognized) by the infrared camera that constitutes the navigation system. The position of the tracker unit 110 in the patient's pelvis can be determined by placing reflective trackers (registered trackers) similar to the reflective markers 111-114 at multiple marker points or reference positions in the pelvis (e.g., anterior superior iliac spine, anterior inferior iliac spine, iliac crest), photographing them with an infrared camera, and measuring the relative positional relationship between each registered tracker and the tracker unit 110. The "position of the tracker unit 110 in the patient's pelvis" determined in this way is registered in the navigation system's computer. This allows the system to track the position (changes) of the tracker unit 110, thereby enabling it to understand changes in the position and orientation of the patient's pelvis.

[0035] After the total hip replacement surgery is performed, the tracker device 100 is removed from the pelvis. The specific procedure involves rotating the fixing member 120 around its axis in the leftward direction (counterclockwise) in this example. By moving the fixing member 120 backward along the path in which it was implanted, it can be removed from the pelvis, thereby allowing the tracker device 100 to be removed.

[0036] According to the tracker device 100 of this embodiment, attachment and detachment operations to the patient's pelvis can be easily performed. Furthermore, the attachment and detachment of the tracker device 100 can be performed solely by manual rotation using a jig (for example, a T-shaped handle for rotating the fixing member 120) as needed, thus ensuring excellent safety. Furthermore, since the fixing member 120 implanted in the pelvis has a wire that is enclosed within the bone tissue, unlike conventional screws which are anchored to the bone by the uneven surface of the screws, the wire is in contact along the spiral perforations. As a result, the tracker device 100 of the present invention is firmly fixed to the pelvis against withdrawal in the direction of the screw's central axis or the spiral circle's central axis, and its withdrawal resistance is extremely high. Furthermore, after the removal of the fixing member 120, the scar remaining on the skin is extremely small, corresponding to the diameter of the wire, and wounds of that size do not require sutures or other treatments. Moreover, the hole remaining in the pelvis can be closed with small bone tissue that regenerates in a short period of time. Considering these factors, the tracker device 100 of this embodiment is extremely invasive to the patient.

[0037] <Second Embodiment> The tracker device 200 of this embodiment, shown in Figures 2A and 2B, is a tracker device that constitutes a navigation system used when performing total hip replacement surgery, and is fixed to the patient's pelvis, similar to the tracker device 100 of the first embodiment.

[0038] This tracker device 200 comprises a tracker unit 210 and a fixing member 220. The configuration of the tracker unit 210 is the same as that of the tracker unit 110 in the first embodiment.

[0039] The fixing member 220 constituting the tracker device 200 consists of a helical coil having a pointed end 221. This fixing member 220 is formed from a wire having a square cross-section, and the pointed end 221 of the fixing member 220 is approximately square pyramidal or approximately square truncated pyramidal (the top may be rounded). The materials used to construct the fixing member 220 are the same as those used for the fixing member 120 of the tracker device 100 in the first embodiment.

[0040] The thickness of the wire forming the fixing member 220 (the length of the sides s of the square cross-sectional shape) is preferably 1.5 to 3.0 mm, and more preferably 1.8 to 2.5 mm. The outer diameter (coil diameter) D, pitch (coil pitch) p, and length (coil length) L of the fixing member 220 are the same as those of the fixing member 120 of the tracker device 100 in the first embodiment.

[0041] The tracker device 200 of this embodiment can achieve the same effects as the tracker device 100 of the first embodiment.

[0042] <Third Embodiment> The tracker device 300 of this embodiment, shown in Figure 3, is a tracker device that constitutes a navigation system used when performing total hip replacement surgery, and is fixed to the patient's pelvis, similar to the tracker device 100 of the first embodiment.

[0043] This tracker device 300 comprises a tracker unit 310 and a fixing member 320. The configuration of the tracker unit 310 is the same as that of the tracker unit 110 in the first embodiment.

[0044] The fixing member 320 that constitutes the tracker device 300 is made of a helical coil having a pointed end 321. The fixing member 320, which consists of a helical coil, is formed from a wire (round wire) having a circular cross-section, and its tip 321 is cut with a cutting edge. In other words, the fixing member 320 has the same configuration as the fixing member 120 of the tracker device 100 of the first embodiment, except that its tip 321 is cut with a cutting edge.

[0045] As shown in Figure 3, the tip 321, which has been cut with a cutting edge, is roughly triangular pyramidal in shape, and an edge is formed on the side (side ridge) of the triangular pyramid.

[0046] The tracker device 300 of this embodiment can achieve the same effects as the tracker device 100 of the first embodiment. Furthermore, the cutting edge at the tip 321 of the fixing member 320 enhances its sharpness, and the formed edge allows for efficient removal of cortical bone tissue on the surface of the pelvis, thus enabling smoother insertion of the fixing member 320 into the pelvis.

[0047] <Fourth Embodiment> The tracker device 400 in this embodiment, shown in Figure 4, is a tracker device that constitutes a navigation system used when performing total hip replacement surgery and is fixed to the patient's pelvis.

[0048] This tracker device 400 comprises a tracker unit 410 and a fixing member 420. The configuration of the fixing member 420 is the same as that of the fixing member 120 in the first embodiment.

[0049] The tracker unit 410, which constitutes the tracker device 400, has a two-dimensional tracker on which optically readable information (image information such as a two-dimensional matrix) is printed.

[0050] The tracker device 400 of this embodiment can achieve the same effects as the tracker device 100 of the first embodiment.

[0051] Although embodiments of the present invention have been described above, the present invention is not limited to these and various modifications are possible. For example, the markers mounted on the tracker unit may be self-illuminating markers. The tracker unit may also be equipped with an optical sensor. Furthermore, the cross-section of the wire forming the fixing member (spiral coil) may be a quadrilateral other than a square (such as a rhombus, rectangle, trapezoid), semicircle, ellipse, triangle, pentagon, or hexagon. Furthermore, the tip of the fixing member may be subjected to cutting edge processing other than that shown in the third embodiment. Furthermore, the tracker device of the present invention can be fixed to the femur, tibia, or other bones of the patient, in addition to the pelvis. [Explanation of Symbols]

[0052] 100 Tracker Devices 110 Tracker Unit 111-114 Reflective Markers 120 Fixing member 121 Tip of the fixing member 200, 300, 400 Tracker Devices 210, 310, 410 Tracker Unit 220, 320, 420 Fixing members 221 321,421 Tip of the fixing member

Claims

1. A tracker device comprising a navigation system used when performing orthopedic surgery, comprising a tracker unit having at least one optical marker, and a fixing member for fixing the tracker unit to the patient's bone, wherein the fixing member is made of a helical coil having a pointed end, A tracker device in which the helical coil is formed from a wire having a circular cross-section, the diameter (d) of the wire being 1.2 to 3.0 mm, the coil diameter (D) being 2.8 to 12 mm, the coil pitch (p) being 2.4 to 30 mm, and the coil length (L) being 8 to 140 mm.

2. The ratio of the coil diameter to the wire diameter (D / d) is 1.5 to 5. The tracker device according to claim 1, wherein the coil pitch (p / d) with respect to the diameter of the wire is 1.35 to 6.

3. The tracker device according to claim 1 or 2, wherein the tip end of the helical coil is subjected to cutting edge processing.

4. The tracker device according to claim 1 or 2, wherein the fixing member is detachably attached to the tracker unit.

5. The tracker device according to claim 1 or 2, wherein the tracker unit has at least one light-reflecting marker or light-emitting marker.

6. The tracker device according to claim 1 or 2, wherein the tracker unit has a two-dimensional tracker on which optically readable information is printed.

7. A tracker device according to claim 1 or 2, which is fixed to the patient's bone when performing artificial joint replacement surgery.

8. A tracker device according to claim 7, which is fixed to the patient's pelvis when performing artificial hip replacement surgery.

9. The tracker device according to claim 7, which is fixed to the femur of a patient when performing artificial hip replacement surgery.

10. The tracker device according to claim 7, which is fixed to the femur or tibia of a patient when performing total knee replacement surgery.

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