Trackable protective packaging for tools and methods for calibrating tool installation using the same

Protective packaging, surgical kits, systems, and methods are described herein for assisting in determining whether a tool is properly installed on a surgical device. The protective packaging retains the tool and has trackable features defined relative to a tool center point of the tool. The trackable features have a predetermined state defined relative to the tool center point and the trackable features are configured to be detectable by a localizer to locate the tool center point. One or more controllers can compare the actual state of the tool center point with an expected state of the tool center point, which is based on an expected condition in which the tool is properly mounted to the surgical device. Based on the comparison, the one or more controllers can determine whether the tool is properly mounted to the surgical device.

BACKGROUND

A surgical device, such as a robot, often receives a tool or instrument for use during a surgical procedure. The tool may be a cutting accessory, such as a saw, bur drill, having a head with sharp features configured to resect tissue such as bone. Exposed handling of the tool may result in surgical site infection, injury, and other undesirable consequences. For these reasons, such tools often require a type of protective packaging to prevent inadvertent exposure before and during installation.

A working portion of the tool (e.g., such as the burring portion) must be precisely known by the system in order to effect proper control of the surgical device. Navigation systems are often utilized with surgical systems to track surgical devices, the patient, and additional tools that may be utilized in the surgical procedure. The navigation system often utilizes markers or trackers that are attached to the objects that need to be tracked.

Tool accessories, such as those mentioned above, are interchangeably installed, often operate a high rate of movement and have high exposure to the surgical site thereby requiring sterilization. Therefore, markers or trackers on the tool may negatively affect physical performance of the tool or may be impossible to practically implement on the tool. Furthermore, markers on the tool would likely be destroyed during sterilization. For these reasons, such tool accessories are often not directly tracked by the navigation system.

In such situations, there may be no way of knowing whether the tool is properly installed to the surgical device. There may be situations where the tool appears to be properly installed to the operator, when in fact, the tool may be slightly (e.g., by a few millimeters) mis-aligned or not fully seated.

Prior techniques for confirming tool installation require additional instruments, such as tracked digitization devices, that are used to digitize certain points on the tool for calibration purposes. However, such techniques require additional tools and operator steps thereby increasing operating time and costs. Additionally, digitization techniques may produce measurements that are less accurate because the process requires manual operator involvement in digitizing. For example, the actual digitization point may deviate from the digitization point expected by the system.

Another prior method to assess installation accuracy is to use a custom end effector for a robotic system whereby the end effector has markers or tracking elements detectable by the navigation system and the tool accessory is already in a pre-installed, fixed position, relative to the end effector. In such instances, the robot must move to certain poses to implement a calibration process. In these poses, a kinematic location of the robot is known to the system and the locations of the tracking elements on the end effector are compared to the kinematic robot locations to assess accuracy. However, such methods are not suitable for end effectors that can accept different tools. Furthermore, the end effector must be customized with the given tool and therefore, this increases costs and complexity in end effector versions. Additionally, this technique requires the robot to assume certain poses, thereby increasing operating room time.

Techniques designed to overcome one or more of the aforementioned disadvantages are desired.

SUMMARY

In one example, a method for operating a system is provided, the system comprising a surgical device and a tool for mounting to the surgical device, the tool including a working portion having a tool center point, a protective packaging for retaining the working portion, the protective packaging comprising trackable features having a predetermined state defined relative to an actual state of the tool center point, one or more controllers configured to store the predetermined states of the trackable features and to store an expected state of the tool center point based on an expected condition in which the tool is properly mounted to the surgical device, and a localizer, the method comprising: detecting, with the localizer, actual states of the trackable features in a coordinate system; determining, with the one or more controllers, the actual state of the tool center point in the coordinate system based on the actual states of the trackable features detected by the localizer and the predetermined state of the trackable features defined relative to the actual state of the tool center point; comparing, with the one or more controllers, the actual state and expected state of the tool center point; and evaluating, with the one or more controllers, whether the tool is properly mounted to the surgical device based on comparing the actual state and expected state of the tool center point.

In another example, a system is provided. The system comprising: a surgical device; a tool configured to mount to the surgical device and comprising a working portion having a tool center point; a protective packaging configured to retain the working portion of the tool, the protective packaging comprising trackable features having a predetermined state defined relative to an actual state of the tool center point; one or more controllers coupled to the surgical device and configured to store the predetermined states of the trackable features and to store an expected state of the tool center point based on an expected condition in which the tool is properly mounted to the surgical device; and a localizer coupled to the one or more controllers and being configured to detect actual states of the trackable features in a coordinate system; and wherein the one or more controllers are configured to: determine the actual state of the tool center point in the coordinate system based on the actual states of the trackable features detected by the localizer and the predetermined state of the trackable features defined relative to the actual state of the tool center point; compare the actual state and expected state of the tool center point; and evaluate whether the tool is properly mounted to the surgical device based on comparing the actual state and expected state of the tool center point.

In another example, a protective packaging for a tool is provided, wherein the tool includes a working portion and a tool center point associated with the working portion, the protective packaging comprising: a distal section defining a cavity configured to retain the working portion; and the distal section comprising trackable features, wherein the trackable features have a predetermined state defined relative to a state of tool center point, and the trackable features are configured to be detectable by a localizer for enabling the localizer to locate the tool center point.

In another example, an assembly for a surgical procedure is provided, the assembly comprising: a tool including a working portion and a tool center point associated with the working portion; and a protective packaging that retains the working portion, and wherein the protective packaging comprises trackable features, wherein the trackable features have a predetermined state defined relative to the tool center point and the trackable features are configured to be detectable by a localizer for enabling the localizer to locate the tool center point.

DETAILED DESCRIPTION

Described herein are trackable protective packages for tools, and systems and methods for tracking the protective packaging for various purposes, such as to confirm installation of the tool to a surgical device.

A. Examples of Protective Packaging for Tools

Referring toFIG.1, a non-limiting example of a protective packaging22is illustrated. The protective packaging22is specifically shaped to accommodate and retain a tool24and provides safe, sterile and secure handling of the tool24during storage, transport, and mounting of the tool24on a surgical device28(seeFIGS.3and5). In view of the techniques described below, having the protective packaging22be utilized during or after mounting of the tool24on the surgical device28provides significant advantages.

The protective packaging22and its uses during tool24installation can be like those described in US Pat. App. Pub. No. 2018/0296297A1, entitled “Packaging Systems and Methods for Mounting A Tool on A Surgical Device”, the disclosure of which is hereby incorporated by reference in its entirety. However, the protective packaging22can have different configurations from the protective packaging22shown.

In one example, the tool24is a device that is configured to remove material from a target site, such as a bone of a patient, soft tissue, or the like. For these reasons, the tool24is likely to be a sharp object. The tool24can also be a passive object, i.e., a purely mechanical object having no actively energizable electrical components. Examples of tools24include, but are not limited to burs, drill bits, screw drivers, saws, and the like.

The tool24comprises a working portion W or energy applicator. The working portion W is a feature of the tool24that is configured to interact with and manipulate the target site. When the tool24is a bur, the working portion W is the bur head26rigidly coupled to a tool shaft25(as shown). When the tool24is a drill bit, the working portion W can be the threaded portion of the drill shaft or a distal tip of the drill bit. When the tool24is a saw, the working portion W can be a distal tip or teeth of the saw blade. For simplicity in description, the tool24described in the examples below is a bur and the working portion is the bur head26. However, various other tools24with different working portions W are fully contemplated to be utilized with the techniques described herein.

The surgical device28may be any apparatus configured to receive and operate the tool24. In other words, the surgical device28may provide actuation, control, power, etc., to the tool24. The surgical device28ofFIGS.3-5is a surgical robot R having an end effector configured to receive the tool24. In this example, the surgical device28can be the robot R and/or the end effector. Other example combinations of the tool24and the surgical device28are contemplated. For example, possible combinations may include: a saw or a blade configured to be received by a saw driver; a router, a curved bur, or a sleeve connector for a bur configured to be received by a handheld rotary instrument; electrodes configured to be received by a smoke evacuation pencil; a scalpel configured to be received by a scalpel handle; an ultrasonic tip configured to be received by an ultrasonic aspirator; and an endoscopic shaver or cutter configured to be received by an endo-handpiece. For any of the example above, the surgical device28can be a hand-held instrument configured to be supported (against the force of gravity) and manually moveable in space by the hand and arm of a user. It is to be understood that other surgical devices for receiving tools are contemplated. As will be described below, the tool24and/or surgical device28according to any configuration may be tracked by a navigation system.

In one example, the tool24includes a distal region27and an attachment portion29. The working portion W is at the distal region27of the tool24and the attachment portion29is the part of the tool24that installs to the surgical device28. In some instances, the attachment portion29is located a proximal region of the tool24, opposite the distal region27. At the distal region27is a distal end30and at the attachment region29is a proximal end32of the tool24. A length of the tool24can be defined between the distal end30and the proximal end32. If the tool24is symmetrical about an axis of rotation, a tool axis may be defined between the distal end30and the proximal end32.

In this example, the protective packaging22provides a casing that comprises a distal section34that has a cavity to retain the distal region27of the tool24to protect the operator and prevent contamination. The distal section34may comprise distal portions36,38that collectively retain the tool24. The distal portions36,38can be separate components or can be integrally formed as one component. The distal portions36,38may be pivotably coupled to one another such that they can open and close, in a clamshell configuration. In such examples, the distal section34can be opened to enable removal of the tool24from the protective packaging22and closed to enable retention of the24in the protective packaging22. In other examples, the distal portions36,38can be permanently coupled together, such as by using a high frequency weld, adhesive, integrally formed material, etc. In such examples, the protective packaging22can be configured to slide over and off the tool24.

In some examples, the protective packaging22can have only the distal section34. In other examples, such as that shown inFIG.1, the protective packaging22can optionally include a proximal section40that couples to the distal section34. The proximal section40can be provided with a cavity to retain the proximal end of the tool24, such as the tool shaft25. The proximal section40can be pivotably coupled to the distal section34at a hinge42. This hinge42enables the proximal section40to be detached from the tool shaft25simultaneously while remaining hinged to the distal section34. This way, the tool shaft25can be exposed for installation while the proximal section40can provide shielding protection for the operator's hand. In other examples, the hinge may comprise a perforation44that enables the proximal section40to be detached completely from the distal section34.

Importantly, the protective packaging22provides a low dimensional tolerance and/or tight mechanical fit when retaining the tool24. Features may be designed into the tool24and/or the protective packaging22to achieve the fit. For example, a hole could be placed in a saw blade with a mating protrusion in the protective packaging22, or an undercut could of a drill shaft could be used to align with a protrusion in the protective packaging22. As will be described below, the tight tolerance securely retains the tool24while providing a known relationship between features of the protective packaging22(e.g., trackable features) and the tool24. In one example, the dimensional tolerance is less than 1 mm or even less than 0.1 mm. Any suitable casing of the protective packaging22is contemplated that protect the operator and prevent contamination while maintaining a tight mechanical retention of the tool24. Hence, the casing of the protective packing22is not limited to the examples described herein.

The protective packaging22may comprise, in part or entirely, material such as polyethylene terephthalate glycol-modified (PETG). Other suitable materials may include, without limitation, polymers such as polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), and polystyrene (PS), epoxy and other resins, and malleable metals such as aluminum. The protective packaging22can be formed by thermoforming, injection molding, vacuum molding, blow molding, or other manufacturing processes.

Various different configurations of the protective packaging22are contemplated. For example, the protective packaging22can be hermetically sealed (against liquid and gas). The protective packaging22can be reusable (sterilizable) or disposable (single use). The protective packaging22can have features, such as texturized features, to enable the operator to easily grip the protective packaging22for tool24installation or to open and close the distal portions36,38. The protective packaging22or any of its components can be adjustable in size or dimension, and can be elastic, flexible, or deformable. The protective packaging22can be tool24specific or generically usable for different tools. As will be described below, the protective packaging22can also have features that enable the protective packaging22to be detectable and/or to avoid being detectable.

The protective packaging22can be used for initial attachment of the tool24to the surgical device28or it can be used for re-attachment of the tool24during the surgical procedure. There may be a need to re-check the position of the tool24during the procedure or the tool24may be removed for a portion of the procedure and later re-installed. The protective packaging22can have any combination of the features described herein and can have configurations or features other than those described herein.

B. Trackable Features for the Protective Packaging

As shown in the non-limiting example ofFIGS.1and2, the protective packaging22can comprise one or more trackable features T. The trackable features T can be utilized to track the tool24when the tool24is retained by the protective packaging22. The trackable features T can also be utilized to track the protective packaging22when the tool24is not retained therein. In another example, described below, the trackable features T are utilized to determine whether or not the tool24is properly mounted/installed to the surgical device28.

The protective packaging22may comprise any number and any configuration of trackable features T. In this example, three trackable features T1-T3are provided with the protective packaging22. Having at least three trackable features T provides the ability to know the position and orientation of the protective packaging22. The trackable features T can be placed on or affixed to the protective packaging22utilizing any suitable technique. Alternatively, the trackable features T can be integrally formed on, in, or with the protective packaging22. For example, the trackable features T can be embedded within the material of the protective packaging22. The trackable features T can also be uniquely identifiable features integral to the protective packaging22, such as edges, protrusions, recesses, shapes or any of the components of the protective packaging22described herein.

The trackable features T can be passive or actively energized and can be of any appropriative type of detectable configuration. The trackable features T may be infrared trackable features. When infrared, the trackable features T can be retroreflective elements or LED emitters, for example. Alternatively or additionally, the trackable features T can be passive landmarks, patterns, and/or shapes that are uniquely identifiable. The trackable features T can also be configured with patterns, colors, gradients, and/or texturized materials. In other examples, the trackable features T can be passive or active magnetic or electro-magnetic elements, passive or active radio frequency elements, radio-opaque elements, ultrasound detectable elements, or any combination of the above-described configurations.

The trackable features T can be provided on the protective packaging22in any location, manner, or configuration. For example, the trackable features T can be positioned the first and/or second distal portions36,38. The trackable features T can also be positioned on the proximal section40. In one example, the trackable features T are provided only on the distal section34, but not the proximal section40. This configuration is based on the practical consideration that the working portion W of the tool24will remain retained by the distal section34during tool24installation, whereas the proximal section40may be detached from the protective packaging22or otherwise pivoted relative to the distal section34prior to installation. Furthermore, the trackable features T can be positioned on one side or multiple sides of the protective packaging22, including any of the top, bottom, or left or right sides, as needed, to enable the trackable features T to be detectable.

In another example, each of the first and second distal portions36,38comprises an exterior surface, which is exposed when the protective packaging22is closed. In this example, one or more trackable features T can be coupled to the exterior surface of at least one of the first and second distal portions36,38. As such, the trackable features T can be readily visible when the protective packaging22is closed.

In yet another example, the trackable features T may comprise sub-components on different parts of the protective packaging22. For example, each of the first and second distal portions36,38comprises an interior surface. The interior surfaces engage each other when the protective packaging22is closed. In this example, one or more trackable features T comprise a first component coupled to the interior surface of the first distal portion36and a second component coupled to the interior surface of the second distal portion38. The first and second components are positioned such that when the protective packaging22is closed, the first and second components engage or combine to form the trackable feature T. In other words, the trackable feature T may be functional when the protective packaging22is fully closed and non-functional when the protective packaging22is partially or entirely open. The first and second components can be electrical, magnetic, or layers of material (e.g., reflective material) that work together to form the trackable feature T when the protective packaging22is closed. The trackable features T can also extend through the material of the protective packaging22such that the trackable feature T is on both the exterior and interior surfaces of the protective packaging22.

The protective packaging22may comprise a material that is transparent to light. The transparent material can increase visibility and/or reduce retro-reflectivity of the protective packaging22to increase accuracy in detecting the trackable features T. When transparent, visible light penetration through the protective packaging22material may be greater than 75%, 90%, or 95%. The protective packaging22can also be equipped with surface properties or features to reduce retro-reflectivity. Examples of such properties or features include, but are not limited to, rough surfaces, dimpled surfaces, anti-reflective coating or film, or the like.

The trackable features T and the configuration of the protective packaging22can be different than the examples described above.

C. Example Navigation Systems

To implement tracking of the trackable features T, a navigation system100is provided, as shown inFIG.3, for example. The navigation system100can be utilized in conjunction with the surgical device28. As shown inFIG.3, for example, the surgical device28is the end effector of the robot R that is configured to receive the tool24.

The navigation system100is configured to track movement of various objects. Such objects include, for example, the protective packaging22, the robot R, the surgical device28and the anatomy of a patient. The navigation system100tracks these objects with respect to a (navigation) localizer coordinate system LCLZ. Coordinates in the localizer coordinate system LCLZ may be transformed to the robot (manipulator) coordinate system MNPL, and/or vice-versa, using transformation techniques described herein.

One example of the navigation system100, surgical robot, control techniques, and transformations associated therewith, which can be utilized with the techniques herein, is described in U.S. Pat. App. Pub. No. 2018/0168750A1 filed on Dec. 13, 2017, entitled, “Techniques for modifying tool operation in a surgical robotic system based on comparing actual and commanded states of the tool relative to a surgical site,” the entire disclosure of which is hereby incorporated by reference.

The navigation system100may include a cart assembly102that houses the one or more controllers104, such as a navigation computer, and/or other types of control units. The one or more controllers104may also be located in the surgical device28and/or a cart of the robot R. The one or more controllers104may be located in components or subsystems other than that shown inFIG.3and may be implemented on any suitable device or devices in the system100other than the configuration shown. In one example, the controllers for the navigation system and the robot are two different controllers performing different operations, and can be configured, for example, as described in U.S. Pat. App. Pub. No. 2018/0168750A1. The one or more controllers104can comprise software and/or hardware configured to perform all the tasks described herein. Example of hardware may comprise processors, CPUs, microprocessors, integrated circuits, non-transitory memory, graphic processing units, hard drives, and input/output devices.

A navigation interface is in operative communication with the one or more controllers104. The navigation interface includes one or more displays106. The one or more controllers104is capable of displaying graphical (actual or virtual) representations of the relative states of the tracked objects to the operator using the one or more displays106. As will be described below, alerts, notifications, or error messages can also be represented on one or more of the displays106.

In addition to the trackable features T described with respect to the protective packaging22, the other objects tracked by the navigation system100include one or more trackers or trackable features. In one example, as shown, the trackers may include a tool tracker108attached to surgical device28(e.g., end effector), a robot tracker109attached to the base of the robot R (as shown) or to one or more links of the robot R, and target site trackers (not shown), which can be attached to a patient. Any one or more of the trackers may include active or passive trackable features, and may be used with any tracking modality described herein.

The navigation system100also includes a navigation localizer110(hereinafter “localizer”) that tracks a state of trackable features T on the protective packaging22, and other trackers or trackable features. As used herein, the state of an object includes, but is not limited to, data that defines the position and/or orientation of the tracked object or equivalents/derivatives of the position and/or orientation. For example, the state may be a pose of the object, and may include linear data, and/or angular velocity data, and the like. The localizer110provides the state of these tracked objects to the one or more controllers104to enable the one or more controllers104to make determinations based on such information.

In one example, as shown inFIG.3, the localizer110is an optical localizer and includes a camera unit112with one or more optical sensors114. The localizer110can be an infrared based localizer suitable for detecting trackable features T that are configured with active or passive infrared elements. Although one embodiment of the navigation system100is shown inFIG.3, the navigation system100may have any other suitable configuration for tracking the trackable features T.

Additionally, or alternatively, the localizer110can be a machine vision system, The machine vision system can comprise a camera that is configured to detect trackable features T that can include patterns, shapes, colors, textures, gradients and/or uniquely identifiable features provided by the protective packaging22. The machine vision system can employ various types of imaging and imaging processing modalities, such as 2D/3D visible light imaging, depth maps, pixel analysis, edge detection, pattern recognition, and the like. One example of a machine vision system that can be utilized is described in US Publication No. 2017/0143432A1, entitled, Systems and Methods for Establishing Virtual Constraint Boundaries,” the entire contents of which are incorporated by reference herein.

In another example, the navigation system100and/or localizer110are radio frequency (RF)-based. For example, the navigation system100may comprise an RF transceiver in communication with the one or more controllers104. The trackable features T of the protective packaging22may comprise RF emitters or transponders. The RF emitters or transponders may be passive or actively energized. The RF transceiver transmits an RF tracking signal and generates state signals to the one or more controllers104based on RF signals received from the RF emitters. The one or more controllers104may analyze the received RF signals to associate relative states thereto. The RF signals may be of any suitable frequency. The RF transceiver may be positioned at any suitable location to effectively track the objects using RF signals. Furthermore, the RF emitters or transponders may have any suitable structural configuration that may be much different than the trackers or trackable features as shown in the Figures.

The navigation system100and/or localizer110can also be electromagnetically based. For example, the navigation system100may comprise an EM transceiver coupled to the one or more controllers104. The trackable features T of the protective packaging22may comprise EM components, such as any suitable magnetic tracker, electro-magnetic tracker, inductive tracker, or the like. The trackable features T may be passive or actively energized. The EM transceiver generates an EM field and generates state signals to the one or more controllers104based upon EM signals received from the trackers. The one or more controllers104may analyze the received EM signals to associate relative states thereto. Again, such navigation system100embodiments may have structural configurations that are different than the navigation system100configuration as shown throughout the Figures.

In another example, the navigation system100and/or localizer110are ultrasound-based. For example, the navigation system100may comprise an ultrasound imaging device coupled to the one or more controllers104. The ultrasound imaging device images any of the aforementioned objects, e.g., the protective packaging22and/or trackable features T generate state signals to the one or more controllers104based on the ultrasound images. For example, the ultrasound imaging device may be a portable device whose position is tracked. The portable device can be positioned proximate to any object to track the object. The one or more controllers104may process the images in near real-time to determine states of the objects. The ultrasound imaging device may have any suitable configuration and may be different than the camera unit112as shown inFIG.3.

The navigation system100and/or localizer110may be based on any combination of the tracking modalities above and may have any other suitable components or structure not specifically recited herein. Furthermore, any of the techniques, methods, and/or components described above with respect to the camera-based navigation system100shown throughout the Figures may be implemented or provided for any of the other embodiments of the navigation system100described herein.

D. Tool Center Point and Relationship to Protective Packaging

According to the techniques described herein, the trackable features T of the protective packaging22are utilized to track the tool24when the tool24is retained by the protective packaging22. More specifically, the navigation system100can track the trackable features T to determine whether or not the tool24is properly mounted/attached to the surgical device28.

To help facilitate this technique, the protective packaging22provides a low dimensional tolerance and tight mechanical fit when retaining the tool24. Furthermore, the protective packaging22is involved with the process of installing the tool24to the surgical device28. Therefore, tracking the protective packaging22to determine whether or not the tool24is properly mounted/attached to the surgical device28provides the advantages of reducing steps and reducing additional devices in the operating room. Furthermore, the tight tolerance provides measurements with a high degree of accuracy as compared with prior techniques. The tight tolerance provided by the protective packaging22enables the techniques herein to treat the protective packaging22as a virtual extension of the tool24geometry for calibration or verification purposes. By providing tracking features on the protective packaging22, permanent tracking features on the tool24(particularly near the working portion) can be avoided. Avoiding permanent tracking features on the tool24is advantageous since permanent tracking features on a tool24can interfere with tool24operation or with the surgical site and cannot be located proximate enough to working portion of the tool24since the working portion is utilized to manipulate the anatomy. On the other hand, the protective packaging22is installed on the working portion, and hence, maximizes the calibration and verification measurement capability to the distal-most portion of the tool24. Furthermore, the methods described herein provide a seamless user experience, as accuracy checks can be done without adding external components or steps.

Referring toFIG.2, the tool24comprises a tool center point (TCP), which in one embodiment, is a predetermined reference point defined at the working portion W or relative to the working portion W. In one embodiment, the TCP is assumed to be located at the center of a spherical of the tool24such that only one point is tracked. The TCP may relate to a bur having a specified diameter. Often, the TCP is defined at a location that is at a center of the working portion W. For example, as shown inFIG.2, the TCP is located at the spherical center of the bur. However, this may not always be the case. For example, the TCP of a drill bit can be a point in the cylindrical center of the drill, but located anywhere along the tool shaft25. Similarly, for a saw blade, the TCP can be located anywhere on the saw blade. The TCP can also be arbitrarily defined somewhere with respect to the working portion W. Therefore, the term “center” is not limited to the geometrical center of the working portion W. The TCP may be defined according to various manners depending on the configuration of the working portion W.

Furthermore, the TCP can be a physical point on the working portion W or the TCP can be a virtual point. In either instance, the one or more controllers104is configured to store the predetermined TCP state relative to known geometry for the specified tool24. Aside from the techniques described herein for confirming installation of the tool24, the TCP can also be utilized by the one or more controllers104to facilitate control of the tool24and/or surgical device28. For example, such control can be movement of the tool24relative to virtual boundaries or tool paths. Examples of TCPs and uses thereof in controlling surgical devices can be like those described in US Pat. App. Pub. No. 2018/0168750A1, entitled “Techniques for modifying tool operation in a surgical robotic system based on comparing actual and commanded states of the tool relative to a surgical site,” the entire contents of which are hereby incorporated by reference.

In instances where the tool24is not directly tracked by the navigation system100, the state of the working portion W relative to the surgical device28or relative to the navigation system100may not be known. Advantageously, when the tool24is retained by the protective packaging22, the actual state of the TCP can be determined since the protective packaging22has trackable features T. As used herein, the “actual” state of the TCP is the real position and/or orientation of the TCP in physical 3D space or in a global coordinate system. In one example, this global coordinate system is the localizer coordinate system LCLZ. To facilitate this determination, the trackable features T are specifically positioned on the protective packaging22with a predetermined state defined relative to the actual state of the TCP. The one or more controllers104is configured to store these predetermined states of the trackable features T relative to the actual state of the TCP for further evaluations, as will be described below.

Prior to tracking, the actual state of the TCP can be assumed in the correct state relative to the trackable features T based on the understanding that the tool24is properly retained by the protective packaging22. Mainly, the various features of the protective packaging22described above (e.g., tight mechanical fit) help to ensure that the tool24is properly retained relative to the protective packaging22so as to validate this assumption.

As shown in the example inFIG.2, the trackable features T1-T3(in this case, passive markers) and the actual state of the TCP can be defined in a common coordinate system (e.g., the coordinate system of the protective packaging22). In this example, the actual state of the TCP can be considered the origin of the coordinate system, and the center of each trackable feature T is utilized for the coordinate measurements. However, it is not necessary to define the actual state of the TCP at the origin of the coordinate system nor to utilize the center of each trackable feature T for measurement.

InFIG.2, an X-axis and Y-axis define the coordinate system, where X and Y are distances relative to the origin TCP. There may also be Z-axis coordinates (in and out of the page ofFIG.2) that can be considered in this coordinate system. Z-axis coordinates would be appropriate if any of the trackable features T are defined on a different plane relative to the actual state of the TCP or relative to each other. For simplicity in description and illustration, the Z-axis coordinates are omitted on the assumption that the trackable features T are coplanar with the actual state of the TCP. However, the manner in which the Z-axis coordinates are determined can be like that described herein relative to the X and Y-axis coordinates.

Here, trackable feature T1is defined at −X1, Y1 relative to the actual state of the TCP, trackable feature T2is defined at −X1, −Y3 relative to the actual state of the TCP, and trackable feature T3is defined at X1, Y2, relative to the actual state of the TCP. The coordinate measurements and trackable feature T placement relative to the actual state of the TCP inFIG.2is only one example. Of course, the trackable features T can have other predetermined states relative to the actual state of the TCP depending on factors such as the nature of the TCP, the types and positions of the trackable features T, and the structure of the protective packaging22, etc.

E. Techniques for Evaluating Tool Installation with Tracked Packaging

Referring back toFIG.3, the navigation system100is shown with the tool24coupled to the surgical device28. The operator installs the tool24to the surgical device28by holding the protective packaging22. In this example, it is assumed that an attempt was made to install the tool24to the surgical device28, however, the operator may not be aware whether the tool24is properly installed.

As can be understood from the example ofFIG.2, the state of the actual TCP is known relative to the states of the trackable features T. As will be described below, the trackable features T of the protective packaging22and this known relationship are utilized by the navigation system100and one or more controllers104for determining whether the tool24is properly mounted/installed to the surgical device28.

To facilitate this determination, the navigation system100is shown with various transforms (T) for determining the actual state of the TCP in a global coordinate system, e.g. LCLZ. The transform (T), when calculated, gives the state (position and/or orientation) of a first component in its respective coordinate system relative to the state of a second component in its respective coordinate system. The one or more controllers104calculates/obtains and combines a plurality of transforms (T) from the various components of the system, e.g., for purposes such as to validate installation of the tool24and/or to control the surgical device28or robot R when the tool24is installed. The transforms (T) are computational determinations but are represented inFIG.3by arrows between the subject components for illustrative purposes. The directionality of the arrow head is not intended to limit the direction of the transform. In other words, the transform (T) can give the state of one component with respect to the other, or vice versa.

In one embodiment, each transform (T) is specified as a transformation matrix, such as a 4×4 homogenous transformation matrix. The transformation matrix, for example, includes three unit vectors representing orientation, specifying the axes (X, Y, Z) from a first coordinate system expressed in coordinates of a second coordinate system (forming a rotation matrix), and one vector (position vector) representing position using the origin from the first coordinate system expressed in coordinates of the second coordinate system.

Example systems and methods for obtaining and computing transforms of the various components of the system is explained in U.S. Pat. No. 9,119,655, entitled, “Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes,” and U.S. Pat. App. Pub. No. 2018/0168750A1 filed on Dec. 13, 2017, entitled, “Techniques for modifying tool operation in a surgical robotic system based on comparing actual and commanded states of the tool relative to a surgical site,” the entire disclosures of which are hereby incorporated by reference.

As shown inFIG.3, the transforms include a first transform (T1) between the localizer110and trackable features T of the protective packaging22and a second transform (T2) (best shown inFIG.3A) between the trackable features T and the actual state of the TCP. Other transforms that may be utilized include a third transform (T3) between the localizer110and the surgical device28tracker108, a fourth transform (T4) between the surgical device28tracker108and a reference point on the surgical device28, a fifth transform (T5) between the actual state of the TCP and the reference point on the surgical device28, and/or a sixth transform (T6) between the reference point on the surgical device28and a base of the robot (R).

Transforms (T1) and (T3) are obtained using tracking data from the localizer110. In other words, the localizer110tracks the state of the trackable features T of the protective packaging22and the state of the surgical device28tracker108relative to the LCLZ coordinate system. Transform (T2) is obtained based on the known relationship between the trackable features T of the protective packaging22and the actual state of the TCP of the tool24retained by the protective packaging22, as described in the prior section. Transform (T4) is obtained based on a known relationship between the surgical device28tracker108and the reference point on the surgical device28. Transform (T5) is obtained based on a known relationship between an expected state of the TCP (i.e., the state of the TCP when the tool24is installed properly, which will be described further below) and the reference point on the surgical device28. Transform (T6) can be determined based on kinematic data of the robot (R) stored by the one or more controllers104without intervention from the navigation system100. Alternatively or additionally, transform (T7) can be obtained by localizer110determining the relationship between the surgical device28tracker108and the tracker109at the base of the robot R. Not all of these transforms (T) may be utilized in every instance, and these transforms (T) can be utilized in various combinations.

Any known relationship data (e.g., for transforms T2, T4or T5) is stored by the one or more controllers104and may be fixed (constant or static) or variable. In embodiments where the known relationship data is fixed, the known relationship data may be derived from calibration information relating to the respective components (e.g., the surgical device28, the surgical device28tracker108, and the expected state of the TCP). For example, the calibration information may be obtained at a manufacturing/assembly stage, e.g., using coordinate measuring machine (CMM) measurements, etc. The known relationship data may be obtained using any suitable method, such as reading the known relationship data from a computer-readable medium, an RFID tag, a barcode scanner, or the like. The known relationship data may be imported into system100at any suitable moment such that the known relationship data is readily accessible by the one or more controllers104. In embodiments where the known relationship data is variable, the known relationship data may be measured or computed using any ancillary measurement system or components, such as additional sensors, trackers, encoders, or the like. The known relationship data may also be acquired after mounting the surgical device28tracker108to the surgical device28in preparation for a procedure by using any suitable technique or calibration method.

With reference toFIGS.4and5, the one or more controllers104is configured to evaluate the information described above to determine whether the tool24is properly mounted to the surgical device28. For example, the one or more controllers104can determine whether or not the TCP is in the proper position and take action in response.

InFIG.4, the one or more controllers104is configured to store the expected state of the TCP based on an expected condition in which the tool24′ is properly mounted to the surgical device28. The expected state of the TCP is a virtual state (e.g., point) stored in one or more controllers104memory rather than a physical state on the tool24itself. For this reason, a dotted representation of the tool24′ is shown inFIG.4to represent the expected state of the TCP during an assumed proper installation. Furthermore, inFIG.4, a proper installation line120is shown within the tool receiving portion of the surgical device28to illustrate one example of where a proximal end32of the tool24should be relative to the surgical device28when the tool24′ is properly installed. In this illustration, the hypothetical tool24′ is fully seated within the surgical device28(and hence properly installed) such that the proximal end32of the tool24′ aligns with line120.

This installation representation is for simplicity in description and illustration, and tool24′ installation schemes will vary depending on the type of tool being installed and the configuration of the surgical device28. Hence, the use of an “installation line”120is not intended to limit the nature of proper installation conditions. Indeed, the proper installation between the tool24and the surgical device28may be defined by any suitable number of reference datum having any complexity designated by the respective installation scheme. Additionally, or alternatively, proper installation may be defined by any suitable physical parameter measured between the tool24and the surgical device28, wherein the physical parameter can be correlated with, compared to, or otherwise associated to physical parameters derivable from the trackable features of the packaging22and the TCP. Such physical parameters may include, but not limited to: position, magnitude of displacement, distance, orientation, linear motion or velocity, angular motion or velocity, inertial parameters, force parameters, displacement parameters, pressure parameters, torque parameters. Hence, instead of comparing the expected state of the TCP to the actual state of TCP based on static position, the techniques may be utilized to compare an expected motion of the TCP during expected proper installation to actual motion of the TCP during actual installation. Accordingly, the term “state” is not intended to be limited to a static moment in time, but may encompass a period of time. Hence, the term “state” can be static or dynamic.

Furthermore, the installation scheme between the tool24and the surgical device28may include any suitable sensing devices, including but not limited to, direct (DC) electrical connection sensors, proximity sensors, hall effect sensors, electromagnetic sensors, radio frequency sensors, inductive sensors, capacitive sensors, and the like. These sensors are not intended to replace the techniques described herein, but rather can optionally be utilized in conjunction with the techniques described herein, for purposes such as tool identification, coarse tool installation, or tool presence detection.

The expected state of the TCP can be locally derived from the described known relationship data for transform T5, which can obtained using any manner described above. Additionally, or alternatively, the expected state of the TCP can be based on separate known relationship data obtained about the relationship between the expected state of the TCP and any other portion of the surgical device28, such as the portion that receives the tool24. For any given pose of the robot R or state of the surgical device28, the one or more controllers104can determine the expected state of the TCP based on combining the transforms (T) described above. For example, the expected state of the TCP can be determined by combining any one of the following combinations: (T3+T4+T5), (T5+T6), (T5+T6+T7), etc.

If/when the tool24is properly installed, the expected TCP and the actual TCP states should be identical. Otherwise, if the tool24is improperly installed, the expected TCP and the actual TCP states will be different. Additionally, the trackable features may be different for different tools24. This will allow the system to further identify the tool24being used and/or confirm the correct tool is used.

FIG.5illustrates the actual installation condition of the tool24relative to the surgical device28. In this situation, the tool24is improperly mounted to the surgical device. This error condition is illustrated by distance d between the proximal end32of the tool24and the proper installation line120. In other words, the tool24is not fully seated in the surgical device28. The distance d can be difficult to detect to the human eye, e.g., 1 mm or less. Hence, the tool24is not properly installed, but may appear so to the operator. Although the error condition is represented by distance d in this example, it is possible that the error condition can take other forms depending on the nature of the tool24, the surgical device28, and/or manner of installation. For example, the error condition can be an identification of an incorrect tool, improper rotation, linear position, orientation, damage to the tool, or any combination thereof. Regardless of the nature of the error condition, the techniques described herein are configured to detect the error.

Since the tool24is improperly installed inFIG.5, the state of the actual TCP differs from the state of the expected TCP. In this example, the error condition (distance d) at the proximal end32of the tool24causes a corresponding gap d between the actual TCP and expected TCP states. Of course, other error conditions are possible. For example, a measured distance of the tool24that is offset with the tool insertion axis could indicate the tool24is damaged or is the incorrect tool.

The one or more controllers104can make this determination by obtaining the state of the actual TCP using the transforms (T) described above. Regardless of the pose of the robot R or the state of the surgical device28, the one or more controllers104can determine the actual TCP state based on combining transformations (T1+T2). In other words, the actual state of the TCP is known to the one or more controllers104by the tracked state of the trackable features T of the protective packaging22and the predetermined states of the trackable features (T) defined relative to the actual state of the TCP. The one or more controllers104can arrive at the actual and expected TCP states by combining other combinations of transformations other than those specifically described.

Knowing the states of the actual and expected TCPs, the one or more controllers104can compare them using any suitable method, such as comparing position/orientation matrix data from the transforms, etc. In certain examples, different transformation combinations can be compared to validate comparison results. For example, the state of the actual TCP can be validated in the LCLZ coordinate system by comparing the tracking data of the surgical device28tracker108(transform T3) with the tracking data of the trackable features T on the protective packaging22(transform T1).

If the one or more controllers104determines that the states of the actual and expected TCPs, are different, the one or more controllers104may instruct generation of a notification or alert to inform the operator of the error condition. The alert or notification can be visual and provided on the display106, as shown inFIG.3. The alert can also be audible or haptic. Based on the nature of the error condition determined by the one or more controllers104, the one or more controllers104can issue specific instructions about how to resolve the error condition given the circumstance. For example, the one or more controllers104may generate a notification instructing the operator to “fully insert the tool shaft” or “rotate the tool shaft 180 degrees clockwise”. At any point, the one or more controllers104can re-assess the states of the actual and expected TCPs and inform the operator that the tool24is properly installed if the results of the comparison are favorable.

If the expected TCP state is different from the actual TCP state, the system may propose a decision process. For example the system may ask the user to confirm the correct tool is used, the system may suggest the user replace a damaged tool, and/or the user could instruct the system to accept the position of the actual state of the TCP and use the location for the remainder of the surgical procedure.

In certain instances, the one or more controllers104can be configured with a tolerance or threshold or range of error or acceptance when evaluating the differences between the states of the actual and expected TCPs. For instance, the one or more controllers104can have a tolerance of +/−0.1 mm such that if the states of the actual and expected TCPs are off by less than 0.1 mm, the one or more controllers104can nevertheless determine that the tool24is properly installed. The tolerance may be different from the value given, depending on many factors, such as the mechanical stack-up of components of the system, the nature of the installation, the accuracy of the localizer110, or the like. If the actual state of the TCP falls within acceptable range of the expected state of the TCP tolerance, the state of the actual TCP can be stored by the one or more controllers104as the calibrated TCP state that will be used for controlling the surgical device28.