Universal Tool Adapter for Image-Guided Surgery

Abstract

A tool adapter (18) comprising an adapter arm (102) having a proximal end terminating in a linkage (110) and a distal end having a circular coupling (104), the circular coupling having a center and defining an axis (114) passing through the center perpendicular to the circular coupling, and a tool grip (32) rotatably coupled to the circular coupling to permit rotation of the tool grip about the axis, the tool grip configured to fixedly hold a tool (16) along the axis.

Description

Technical Field

[0001] The present invention generally relates to surgery, and more particularly to a tool adapter used to hold a tool during image-guided surgery.

Background Art

[0002] During surgery, it is often necessary to hold the tools used in the surgery in a relatively fixed state. Although a surgeon performing the surgery can hold the tool, mechanically holding the tool can free the surgeon's hand for other tasks. During image-guided surgery, it is often necessary to track or determine the position of the tool used in the surgery with respect to the patient's anatomical structure with a desired accuracy. Next, an image of the tool can be displayed to the surgeon with respect to an image of the patient's anatomical structure (e.g., magnified on the patient's image) based on the tracked position of the tool.

[0003] The documents incorporated by reference in this application are considered an essential part of this application. If terms are defined in these incorporated documents in a way that conflicts with the definitions made explicitly or implicitly in this specification, only the definitions in this specification should be considered.

Summary of the Invention

Means for Solving the Problems

[0004] One embodiment of the present invention provides a tool adapter, the tool adapter comprising an adapter arm having a proximal end terminating in a connection portion and a distal end having a circular coupling portion, the circular coupling portion having a center and defining an axis passing through the center orthogonally to the circular coupling portion, the adapter arm; a tool grip rotatably coupled to the circular coupling portion so as to allow rotation of the tool grip around the axis and configured to fixedly hold a tool along the axis, the tool grip; and comprising.

[0005] In the disclosed embodiments, the tool grip includes a collet housed in a collet holder, the collet configured to grip the tool when compressed. The collet holder may be held by a circular opening and configured to prevent parallel movement along its axis. The tool adapter may include a collet fastening head configured to screw into the collet holder to perform the compression of the collet.

[0006] In a further disclosed embodiment, the tool adapter includes a position marker fixedly coupled to a proximal end coupling and having a preset spatial relationship with the axis, the position marker having an optical element that enables spatial tracking of the position marker, and the tracking of the position marker enables tracking of the tool held by the tool grip.

[0007] In further disclosed embodiments, the tool adapter includes a torque limiting device coupled to a tool grip and configured to apply a preset threshold torque to the grip, allowing rotation of the tool grip if the threshold torque is exceeded. The torque limiting device may consist of a plurality of pins held within the tool grip and configured to exert force on a circular opening.

[0008] In additionally disclosed embodiments, the tool adapter includes a total indicated runout (TIR) ​​control means coupled to a tool grip and configured to apply a predetermined total indicated runout (TIR) ​​to the tool.

[0009] According to one embodiment of the present invention, a method for performing image-guided surgery is further provided, the method comprising: providing an adapter arm having a proximal end terminating at a coupling and a distal end including a circular coupling, the circular coupling having a center and defining an axis perpendicular to the circular coupling and passing through the center; rotatably coupling a tool grip to the circular coupling, the tool grip being rotatable about the axis and configured to hold a tool fixedly along the axis; fixing a position marker to the coupling at the proximal end of the adapter arm in a predetermined spatial relationship with the axis, the position marker including an optical element capable of spatially tracking the position marker such that tracking of the position marker results in tracking of a tool fixed to the tool grip; and presenting an image of the tracked tool to a surgeon.

[0010] According to one embodiment of the present invention, a method is provided, the method comprising: a step of fixing a position marker to a coupling at the proximal end of an adapter arm, the adapter arm further having a distal end including a circular coupling, the circular coupling having a center defining an axis perpendicular to the circular coupling and passing through the center, the coupling being in a predetermined spatial relationship with the axis; a step of inserting a tool through a tool grip of the adapter arm, the tool grip comprising a collet and rotatably coupled to the circular coupling to allow rotation of the tool grip about the axis, the tool grip being configured to fixally hold the tool along the axis; and a step of compressing the collet, the collet being configured to grip the tool when compressed.

[0011] In the disclosed embodiments, the method includes the step of positioning the end of the tool at a predetermined location to enable calibration of the tool. The method may also include the step of inserting the tool into the patient while the position marker and the tool are being tracked.

[0012] In further disclosed embodiments, collet compression includes the step of rotating the collet fastening head.

[0013] In further disclosed embodiments, the position marker includes an optical element that enables spatial tracking of the position marker, and the tracking of the position marker enables tracking of a tool fixed to an adapter arm.

[0014] This disclosure will be better understood from the following detailed description of its embodiments with reference to the drawings. [Brief explanation of the drawing]

[0015] [Figure 1] The use of a tool adapter in an augmented reality system according to an embodiment of the present invention is schematically shown. [Figure 2A] This is a schematic diagram illustrating an augmented reality assembly according to one embodiment of the present invention. [Figure 2B] This is a schematic diagram illustrating a head-up display according to another embodiment of the present invention. [Figure 3] This is a schematic diagram illustrating an exemplary tool adapter and tool according to one embodiment of the present invention. [Figure 4] This is a schematic exploded view of a tool adapter and tool according to one embodiment of the present invention. [Figure 5] This is a schematic cross-sectional view of a tool adapter and tool according to one embodiment of the present invention. [Figure 6] This is a schematic diagram showing an exemplary tool adapter and tool according to another embodiment of the present invention. [Figure 7] This is a flowchart of the steps performed when using a tool adapter in an augmented reality system, according to one embodiment of the present invention. [Modes for carrying out the invention]

[0016] (overview) During medical procedures performed using an augmented reality system, the tools used in the procedure, such as a screwdriver used for pedicle screws, typically need to be tracked, and the images presented to the medical professional using the system must accurately show the tool and the patient receiving the procedure. To track the tool, a marker is usually attached to the tool, and the marker is tracked by the system. However, for tools that require one or more rotations, or partial rotations, such as a screwdriver, the marker must remain within the tracking system's field of view so that tracking is maintained. Furthermore, to eliminate tracking errors, full display runout must be minimized. In addition, whether using a rotating tool or a fixed tool (i.e., a probe, pointer, or pilot, which do not normally rotate during use), it is desirable to apply a firm gripping force via an adapter to hold the tool in place relative to the marker.

[0017] Embodiments of the present invention provide a solution that addresses both of these problems by attaching a tool adapter with a marker to a tool and configuring the tool adapter to be able to rotate around the tool without changing the spatial relationship between the tool and the marker.

[0018] The tool adapter comprises an adapter arm whose proximal end is a connection to a marker and whose distal end terminates at a circular opening. The tool grip is rotatably coupled to the circular opening so as to allow rotation of the tool grip around an axis defined by the opening, and the tool grip is configured to hold the tool fixedly along the axis.

[0019] The tool grip typically includes a collet housed in a collet holder, and the collet is configured to grip the tool when the collet is compressed. By using the collet, the tool can be firmly and stably held in a centered position. The collet holder is held in a circular opening, and the combination of the collet, the collet holder, and the circular opening results in the tool shaft being accurately maintained along the axis of the opening during rotation, with a very small total indicated runout (TIR) during all rotations. The inventors have found that, in contrast to prior art systems having a TIR on the order of 100 microns, embodiments of the present invention have a TIR on the order of 10 microns, resulting in a significant improvement in the tracking accuracy of the gripped tool. <00,00087> (Description of the system) Hereinafter, all directional references (e.g., up, down, top, bottom, left, right, vertical, and horizontal) are used only for identification purposes to assist the reader in understanding the present invention and are not restrictive, and in particular do not impose limitations on the position, orientation, or use of embodiments of the present invention.

[0021] Referring now to FIG. 1, which schematically shows the use of a tool adapter 18 in an augmented reality system 20 according to an embodiment of the present invention. For purposes of illustration and simplification, in the following description, system  20 is assumed to be used by a healthcare provider 22 in a medical procedure, and adapter 18 is attached to a cylindrical tool 16, such as a screwdriver, using a wrench 180, as will be described in more detail below. Although a medical procedure is assumed herein, it should be understood that embodiments of the present invention can be used in non-medical situations as well.

[0022] System 20 is operated by a healthcare worker 22, who wears an augmented reality assembly 24 that tracks a tool adapter 18, which is described in more detail below with respect to FIG. 2A. Assembly 24 is only one type of tracking system that can track a tool holder, and it should be understood that the scope of the present invention includes any tracking system that can track tool adapter 18 and / or position markers 14 attached thereto.

[0023] Assembly 24 particularly includes an image acquisition device 72, also referred to herein as camera 72, which has a field of view indicated by line of sight 74 and is configured to acquire images in the visible spectrum and / or in a non-visible spectrum such as the infrared (IR) spectrum. The functions of assembly 24, system 20, processor 26, and device 72 are described below. An assembly similar to augmented reality assembly 24 and its operation are described in U.S. Patent No. 9,928,629 to Benishti et al., the disclosure of which is incorporated herein by reference.

[0024] Assembly 24 can be incorporated for mounting on a number of different holding structures on expert 22, and in this figure, the holding structure is assumed to be similar to glasses. Those skilled in the art of augmented reality will recognize other possible structures, such as the incorporation of an augmented reality assembly into a head-up display integrated into a headset worn by a user of system 20, and all such structures are assumed to be within the scope of the present invention. Another exemplary head-up display is described below with reference to FIG. 2B.

[0025] The system 20 comprises a processor 26 and is under the overall control of the processor 26. In one embodiment, the processor 26 is assumed to be integrated into a standalone computer 28, and the processor typically communicates wirelessly with other elements of the system, including an assembly 24, as shown in Figure 1. Alternatively or additionally, the processor 26 may use optical and / or conductive cables for communication. In yet another embodiment, the processor 26 is integrated into or mounted within the assembly 24. The processor 26 can typically access a database 40 containing images and other visual elements used by the system 20. Software that enables the processor 26 to operate the system 20 can be downloaded to the processor in electronic form, for example, over a network. Alternatively or additionally, the software can be provided on non-primary tangible media such as optical, magnetic, or electronic storage media.

[0026] The medical procedure illustrated here is for patient 30, and during the procedure, the position marker 14 is incorporated into the tool adapter 18. As will be described later, the marker 14 is trackable by the processor 26, which can also track the tool adapter to which the marker is attached and the tool 16 held by the adapter.

[0027] Figure 2A is a schematic diagram showing an assembly 24 according to one embodiment of the present invention. As described above, the assembly 24 is configured as a pair of glasses 50 attached to a frame 54 as an example.

[0028] Frame 54 is fitted with at least one image acquisition device 68 and / or 72. Typically, the device 68 and / or 72 comprises a camera configured to acquire images of the scene as seen by the expert eye, including images of the marker 14 in the visible spectrum and / or the non-visible spectrum.

[0029] As described above, assembly 24 includes a camera 72 configured to acquire an image of the elements of the scene, including a marker 14 located in front of assembly 24. The image is generated from radiation projected by a projector 73 in the spectrum detected by camera 72. The projector 73 is positioned close to camera 72, and the back-reflected radiation from the projector is acquired by camera 72. The camera typically has a bandpass filter configured to block other radiation, such as that projected by surgical illumination. Typically, camera 72 and projector 73 operate in the invisible region of the spectrum, such as the near-infrared spectrum. As described below, at least some back-reflected radiation is received, typically from marker 14, and the processor 26 tracks the marker using the image of the marker generated by camera 72 from the received radiation, and as a result tracks the position and orientation of the adapter 18 and tool 16.

[0030] Figure 2B is a schematic diagram illustrating a head-up display (HUD) 700 according to an embodiment of the present invention. The HUD 700 is fitted by a specialist 22 and can be used in place of assembly 24 (Figure 1). The HUD 700 comprises an optical housing 704 incorporating an infrared camera 708. The housing 704 also includes an infrared transparent window 712, and one or more infrared projectors 716 are mounted inside the housing, i.e., behind the window. A pair of augmented reality displays 720 are mounted in the housing 704, and the augmented reality displays 720 are configured to allow the specialist 22 to see entities such as part or all of a patient 30 through the display, and to present the specialist with images or any other information that can be received from a database 40.

[0031] The HUD includes a processor 724 mounted in a processor housing 726, and the processor 724 operates each element of the HUD. The processor 724 typically communicates with the processor 26 via an antenna 728, but in some embodiments, the processor 724 can perform some of the functions performed by the processor 26, and in other embodiments, it can completely replace the processor 26.

[0032] A flashlight 732 is mounted on the front of the HUD700. The flashlight projects visible-spectrum light onto an object so that the expert 22 can clearly see the object through the display 720. Each element of the head-up display is typically powered by a battery (not shown) that powers the element via a battery cable input 736. The HUD700 is held in place on the head of the professional 22 by a head strap 740, and the professional can adjust the head strap using an adjustment knob 744.

[0033] Figure 3 is a schematic diagram showing an exemplary tool adapter 18 and tool 16 according to one embodiment of the present invention, Figure 4 is a schematic exploded assembly diagram of the tool adapter and tool, and Figure 5 is a schematic cross-sectional view of the tool adapter and tool. The tool adapter 18 is formed from an adapter arm 102, which terminates at the upper or distal end of the arm with a circular coupling 104, also referred herein to as a circular opening 104, and at the lower or proximal end of the arm with a coupling 110 that permanently connects the arm to a marker 14. A marker similar to the marker 14 is described in U.S. Patent Application No. 16 / 199,281 by Messinger et al., which is incorporated herein by reference.

[0034] In the disclosed embodiment, the arm 102 is formed as a single unit. However, in other embodiments, the arm 102 can be formed as two or more units that are fixedly coupled together. For example, the opening 104 can be formed as a separate unit from the rest of the arm 102, and the opening can be fixedly coupled to the rest of the arm by some convenient means.

[0035] The tool grip 32 holds the tool 16 in a fixed position, as will be described in more detail below. The tool grip is rotatably coupled to the circular opening 104, and the tool 16 rotates relative to the opening as the grip rotates.

[0036] The circular opening 104 has an internal cylindrical surface 106, typically having a diameter ranging from 10 mm to 50 mm, which defines the axis of symmetry 114 of the opening. The tool grip 32 includes a rigid collet holder 120 having an external cylindrical surface 112 that fits into the opening 104 and has a diameter slightly smaller than the diameter of the internal cylindrical surface 106. Except as described later, the collet holder 120 can rotate freely within the opening 104.

[0037] After the collet holder 120 is assembled into the opening 104, the holder is held in place by an upper circular washer 130 and a lower lock nut 132 to prevent it from moving parallel along the axis 114. The lock nut 132 functions as a washer due to its shape and the material from which it is formed. The washer and nut are typically formed from a low-friction material such as PEEK and function as friction bearings, preventing the holder from moving parallel along the axis 114 while allowing it to rotate around the axis. The upper washer 130 is held in place between a circular projection ridge 136 fixedly formed on the surface 112 and the upper edge 140 of the opening 104.

[0038] The lower lock nut 132 is threaded and configured to engage with the threaded lower region 144 of the holder 120, and is dimensioned to engage with the lower edge 148 of the opening 104. The lower lock nut is held in place in region 144 by adhesive between the nut and region 144, and by a set screw 152 that is screwed into region 144. Mechanisms other than the set screw 152 for holding the lock nut in place, such as dowel pins, are well known to those skilled in the art, and all such mechanisms are assumed to be included within the scope of the present invention.

[0039] As described below, in some embodiments, a lock nut can be used to restrict the rotational degrees of freedom of the arm 102 around the collet holder 120 in a controlled manner.

[0040] The collet 150 fits into the collet holder 120. The collet 150 has a cylindrical upper outer portion 154 and a conical lower outer portion 158. The collet 150 also has a central cylindrical opening 162 that is sized to accept the tool 16 when the collet is not compressed and to grip the tool when the collet is compressed. Embodiments of the present invention include a set of collets, each collet in the set capable of accepting tools having a predetermined range of diameters.

[0041] The collet holder 120 has an upper inner cylindrical surface 166 and a lower inner conical surface 170, and the two inner surfaces are sized to fit with the outer surface of the collet 150 (Figure 5).

[0042] The collet 150 is held in place within the collet holder by a retaining spring 174, which acts as a spring against a dedicated groove on the upper cylindrical surface 166. The collet fastening head 178 is configured to screw into the threaded outer surface 182 of the collet holder 120. The fastening head 178 is configured to engage with the spring 174 internally, so when the head is screwed into the surface 182 so as to move toward the collet holder, the head pushes the spring 174 forward, and therefore pushes and compresses the collet 150.

[0043] An inner cylindrical tube 190 is fixed to the upper surface of the collet fastening head 178, and this tube has an inner diameter larger than the outer diameter of the cylindrical tool 16. The outer surface of the fastening head 178 is configured to be gripped by a wrench 180, which is able to rotate the fastening head. Exemplarily, in one embodiment, the outer surface has a projection 194, and the wrench 180 engages with this projection so that the fastening head can rotate.

[0044] When the tool 16 is positioned within the adapter 18 so as to cross the pipe 190, the rotation of the collet fastening head 178 pushes forward the flat edge of the collet 150, compressing the collet and resulting in a grip on the tool 16. It should be understood that while the tool is gripped by the collet, the adapter arm 102 can rotate around the tool.

[0045] Considering the above description, it can be understood that the tool grip 32 includes, in addition to the arm 102 and the tool 16, the collet holder 120 and other elements described herein that are coupled to the collet holder and collet 150.

[0046] In some embodiments, the arm 102 includes a locking mechanism 200. The locking mechanism 200 includes an operating button 204, which is configured to switch, via a spring and a coupling rod, between engaging or disengaging a pin 208 of the mechanism into one of the holes 212 in the collet holder surface 112. The use of the locking mechanism facilitates the attachment of the tool 16 to the tool adapter 18 by preventing the collet holder 120 from free-rotating around the central axis of the tool while the wrench 180 rotates the fastening head 178.

[0047] In some embodiments, the circular opening 104 has a hole that aligns with the hole 212. The hole in the opening 104 can be used by a professional 22 to align the mechanism 200 with the hole 212, and also facilitates liquid flushing and avoidance of residual liquid when the adapter 18 is cleaned.

[0048] As described above, the marker 14 is fixedly attached to the lower connecting portion 110. In the illustrated embodiment, the marker 14 includes an optical element 12 formed on the marker 14. The element 12 can be formed as a plurality of openings 21 in the upper marker section 15, and the openings are backed by a reverse-reflecting sheet 17 which is held in a predetermined position relative to the openings by a lower marker section 23 fixed to the upper marker section. The marker 14 is fixedly coupled to the lower connecting portion 110 by screws 19.

[0049] Element 12 is typically configured not to have a rotational or reflective axis of symmetry, and the processor 26 uses an image of the marker 14, which includes an image of element 12 acquired by the image acquisition device 68 and / or camera 72 of the assembly 24, to track the marker, i.e., to determine the position and orientation of the marker within a reference frame defined by the assembly.

[0050] In some embodiments, typically in the fabrication of the adapter 18, a lock nut 132 can be used to limit the rotational degrees of freedom of the arm 102 around the collet holder 120 in a controlled manner. In this case, the lock nut functions as a torque limiting device. If there is no restriction on its rotation, a professional 22 may accidentally rotate the arm during treatment. As described herein, such accidental rotation of the arm does not affect the function of the system 20, but such rotation may be undesirable.

[0051] If there is no restriction on the rotation of the arm, it should be understood that when the tool 16 is tightened to the collet holder 120 by the collet 150 and the tool is held horizontally, the weight of the arm 102, i.e., the force on the arm due to gravity, will cause the arm to rotate around the axis 114 to the vertical "6 o'clock" position. As described above, the lock nut 132 can be adjusted to counteract the force of gravity, so that when the tool 16 is held horizontally, the arm 102 does not rotate and remains in the horizontal "3 o'clock" position. The lock nut acts to provide a torque that counteracts the torque generated by gravity. This counteracting torque, also referred to herein as threshold torque, does not completely prevent the rotation of the arm 102, but limits accidental rotation of the arm so that rotation only occurs when the threshold torque is exceeded.

[0052] It should be understood that the threshold torque provided by the lock nut 132 prevents the adapter 18 from rotating due to gravity, but does not add excessive friction that could hinder the smooth rotation of the tool 16 by the expert 22. For a marker with an arm and a mass of 80g and a center of mass 100mm from the axis 114, the threshold torque applied to the arm 192 is approximately 8 N·cm.

[0053] In addition to functioning as a torque limiting device, the lock nut 132 also functions as a means of controlling the total indicated runout (TIR) ​​of the tool gripped by the adapter 18. When the lock nut 132 is set to have a threshold torque of 8 N / cm, the TIR will be approximately 60 microns or less.

[0054] Figure 6 is a schematic diagram showing an exemplary tool adapter 418 and tool 16 according to another embodiment of the present invention. Except for the differences described below, the operation of adapter 418 is generally similar to that of adapter 18 (Figures 1 to 5), and the elements indicated by the same reference numerals in both adapters 18 and 418 are generally similar in structure and operation.

[0055] In contrast to adapter 18, adapter 418 has three substantially similar blind holes 420 formed in the collet holder 120. The blind holes 420 are distributed symmetrically with respect to axis 114 and are orthogonal to the axis.

[0056] Three substantially similar springs 428 are inserted into the blind hole 420, and three substantially similar pins 424 are inserted into the springs. Each pin 424 has an end shoulder 432 having an outer diameter that fits the diameter of the blind hole 420.

[0057] In addition, as shown in Figure 6, after insertion, the springs and pins are sized such that the lower end of each spring contacts the base of the blind hole, the upper end of the spring contacts the shoulder portion 432, and the exposed surface 436 of the shoulder portion protrudes slightly from the surface 112.

[0058] After the adapter 418 is assembled, each surface 436 presses against the inner surface 106 of the opening 104 with a force that is a function of the parameters of the spring 428, i.e., the spring constant of the spring as well as its changed length. As a result, the pressing force generates a frictional force on the opening 104 as the opening 104 rotates or attempts to rotate around the axis 114, and this frictional force provides the threshold torque mentioned above.

[0059] It should be understood that the threshold torque can be set to the above value of 8 N·cm, or a value above or below this value, by selecting a spring with appropriate parameters, and by selecting the material from which the pin 424 and the opening 104 are formed. Therefore, by these selections, any desired threshold torque can be achieved without conducting unnecessary experiments.

[0060] To assemble the tool grip 32, first, the spring 428 and pin 424 are placed in their blind holes. Next, the opening 104 of the holder arm slides over the collet holder 120 and the pin shoulder 432. Finally, the lock nut 132 is screwed onto the holder 120.

[0061] As described above, in contrast to adapter 18, where the lock nut 132 acts to set the TIR value and threshold torque value, adapter 418 allows the two parameters to be set independently. That is, in adapter 418, the lock nut 132 is used to set the TIR value, while the spring 428 and pin 424 are used to set the threshold torque value.

[0062] The above description assumes that there are three sets of springs 428 and pins 424 distributed symmetrically with respect to the axis 114. However, it should be understood that any other convenient set of springs and pins distributed symmetrically with respect to the axis, such as two, four, or five sets of springs and pins, can be used as a torque limiting device.

[0063] Figure 7 is a flowchart of the steps performed when using a tool adapter (e.g., tool adapter 18 or tool adapter 418) disclosed in the augmented reality system 20 (Figure 1) according to one embodiment of the present invention. The steps can be performed by a user of the adapter, such as a professional 22.

[0064] In the first step 300, a marker, such as marker 14, is attached to the tool adapter. For example, marker 14 can be attached to the coupling portion 110 of the arm 102 of the tool adapter. In another example, the tool adapter 418 is assembled as described above with reference to Figures 3 to 6. Assembly typically involves adjusting the lock nut 132 to provide a predetermined TIR, and positioning the pin 424 and spring 428, as described above. In some embodiments, the first step 300 is not necessary if the marker is already attached to or incorporated into the tool adapter.

[0065] In the tool insertion step 304, a cylindrical tool, such as tool 16, is inserted through the opening (e.g., opening 162) of the adapter's collet (e.g., collet 150). Since the tool will be used in the medical procedure mentioned above on the patient (e.g., patient 30), the tool is inserted so that the tip of tool 16 (e.g., tip 16T) is below the height of the marker.

[0066] In the collet operating step 308, the collet is compressed. This compression causes the collet to grip the tool. For example, a wrench 180 is used to rotate the collet fastening head 178 to compress the collet 150, and this compression causes the collet to grip the tool 16. While the wrench 180 is in use, as described above, the locking mechanism 200 needs to act to lock the collet holder 120 in place to facilitate the compression of the collet 150.

[0067] Steps 300–308 provide methods for assembling the tool and tool adapter, and / or for preparing the tool for use during a medical procedure with or within the frame of an image-guided system. Step 310 below refers to calibration steps performed via the image-guided system, and step 316 refers to the use of the adapter for tracking the tool during a medical procedure or surgery.

[0068] As described above, the processor 26 can track the marker 14, access tracking information about the marker 14, or receive such tracking information. Therefore, in calibration step 310, the expert 22 positions the tool end 16T in place, and the processor 26 acquires or accesses an image of the marker 14 (e.g., via cameras 68 and / or 73). From the acquired image, the processor calculates the position of the marker, i.e., its position and orientation, and forms a vector correspondence between the marker position and the tool end 16T and the orientation of the tool 16. That is, the processor translates the marker position into the direction of the tool end 16T and the axis 114. It should be understood that since the marker is fixed to the arm, the vector correspondence does not change even if the arm 102 rotates around the axis 114.

[0069] In the tool insertion step 316, a tool, for example, tool 16, is inserted into the patient (e.g., patient 30) while a marker (e.g., marker 14) is tracked (e.g., by cameras 68 and / or 73 and processor 26). Marker tracking provides the processor with the position and orientation of the marker, i.e., the marker position. From the marker position, the processor can determine the position of the tool end and the orientation of the tool using the vector correspondence found in or following step 310. The processor can use the orientation of the tool and the position of the tool end (or tip) when presenting a properly displayed image in a near-eye assembly or head-mounted assembly such as assembly 24.

[0070] In one embodiment, the tool 16 comprises a screwdriver, which is inserted into the patient 30 so that a specialist 22 can adjust a pedicle screw. It should be understood that as the screwdriver rotates, the processor 26 can still track the orientation and end of the screwdriver using the vector correspondence found in calibration step 310, as long as the marker 14 is being tracked.

[0071] Alternatively or additionally, during positioning of the procedure, the marker 14 may obstruct the specialist's view of the patient and / or the view of the patient acquired by the device 68 and / or camera 72. In either of these cases, and according to some embodiments, the specialist 22 can rotate the arm 102 around axis 114 by applying a torque greater than the threshold torque applied in step 300, so that the marker 14 no longer obstructs the view, but while the marker is continuously being tracked. Since the marker 14 continues to be tracked, the processor can continue to track the tool 16 and tool end 16T using the newly tracked position of the marker, since the spatial relationships, i.e., vector correspondences, between the tool and the marker, and between the tool end and the marker do not change due to the rotation of the tool adapter around axis 114.

[0072] Those skilled in the art will understand that the order of steps 300-316 described above is merely one example of a possible order of steps, and that the steps can be performed in a different order than those given herein. For example, the first step 300 can be performed after the collet acting step 308. All such orders are assumed to fall within the scope of the present invention.

[0073] In the above description, a tool that can rotate around its axis, such as a screwdriver, was used as an example in the tool adapter described herein. However, it should be understood that the tool used in the adapter does not need to rotate. Therefore, the tool used in the adapter can be fixed or non-rotatable around the tool axis.

[0074] The embodiments described above are illustrative examples, and it should be understood that the present invention is not limited to those specifically shown and described above. Rather, the scope of the present invention includes both combinations and partial combinations of the various features described above, as well as variations and modifications thereof not disclosed in the prior art, which can be recalled by those skilled in the art who have read the above description.

Claims

1. A tool adapter, an adapter arm having a proximal end terminating in a link and a distal end including a circular joint, the circular joint having a center and defining an axis passing through the center and perpendicular to the circular joint; a tool grip rotatably coupled to the circular coupling portion to permit rotation of the tool grip about the axis and configured to fixedly hold a tool along the axis; A tool adapter comprising:

2. 10. The tool adapter of claim 1, wherein the tool grip comprises a collet housed in a collet holder, the collet configured to grip the tool when compressed when the tool is inserted through the tool grip.

3. The tool adaptor of claim 2 , wherein the collet holder is retained by the circular opening and configured to prevent translation along the axis.

4. The tool adapter of claim 2 , comprising a collet fastening head configured to thread into the collet holder to effect the compression of the collet.

5. 2. The tool adapter of claim 1, further comprising a position marker fixedly coupled to the coupling portion of the proximal end in a predetermined spatial relationship to the axis, the position marker including an optical element that enables spatial tracking of the position marker, the tracking of the position marker being adapted to enable tracking of the tool held by the tool grip.

6. 10. The tool adapter of claim 1, further comprising a torque limiting device coupled to the tool grip and configured to apply a preset threshold torque to the grip such that rotation of the tool grip is permitted when the threshold torque is exceeded.

7. The tool adapter of claim 6 , wherein the torque limiting device comprises a plurality of pins retained within the tool grip and configured to exert a force against the circular opening.

8. 10. The tool adapter of claim 1, further comprising a total indicated runout (TIR) ​​control coupled to the tool grip and configured to apply a predetermined total indicated runout (TIR) ​​to the tool.

9. 1. A method for performing image-guided surgery, comprising: providing an adapter arm having a proximal end terminating in a link and a distal end including a circular joint, the circular joint having a center and defining an axis passing through the center and perpendicular to the circular joint; rotatably coupling a tool grip to the circular coupling portion such that the tool grip can rotate about the axis, the tool grip configured to fixedly hold the tool along the axis; fixedly coupling a position marker to a connection at the proximal end of the adapter arm in a predetermined spatial relationship to the axis, the position marker including an optical element capable of spatially tracking the position marker such that tracking of the position marker results in tracking of a tool fixed to the tool grip; presenting an image of the tracked tool to a surgical professional; A method comprising:

10. The method of claim 9 , wherein the tool grip comprises a collet housed in a collet holder, the collet configured to grip the tool when compressed.

11. The method of claim 10 , wherein the collet holder is held by a circular opening and configured to prevent translation along the axis.

12. The method of claim 10, including configuring a collet fastening head to thread into the collet holder to effect compression of the collet.

13. 10. The method of claim 9, comprising coupling a torque limiting device to the tool grip and configuring the torque limiting device to apply a preset threshold torque to the grip such that rotation of the tool grip is permitted when the threshold torque is exceeded.

14. The method of claim 13 , wherein the torque limiting device comprises a plurality of pins retained within the tool grip and configured to exert a force against the circular opening.

15. 10. The method of claim 9, further comprising coupling a total indication runout (TIR) ​​control to the tool grip, and configuring the control to apply a predetermined TIR to the tool.

16. fixedly coupling a position marker to a coupling portion at a proximal end of an adapter arm, the adapter arm further having a distal end including a circular coupling portion, the circular coupling portion having a center and defining an axis passing through the center perpendicular to the circular coupling portion, the coupling portion being in a predetermined spatial relationship with the axis; inserting a tool through a tool grip of the adapter arm, the tool grip including a collet and rotatably coupled to the circular coupling to allow rotation of the tool grip about the axis, the tool grip configured to fixedly hold the tool along the axis; compressing the collet, the collet being configured to grip the tool when compressed; A method comprising:

17. The method of claim 16 further comprising positioning an end of the tool at a preset location to allow calibration of the tool.

18. The method of claim 17 , further comprising inserting the tool into the patient while the marker and the tool are tracked.

19. The method of claim 16, wherein compressing the collet includes rotating a collet fastening head.

20. 17. The method of claim 16, wherein the position marker includes an optical element that enables spatial tracking of the position marker, and tracking of the position marker enables tracking of a tool secured to the adapter arm.

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