System for monitoring offset during navigation-assisted surgery
The navigation system addresses inaccuracies in surgical instrument alignment by monitoring tool-to-bone offsets and triggering alerts or power cutoffs, enhancing precision and safety in navigation-assisted surgeries.
Patent Information
- Authority / Receiving Office
- AU · AU
- Patent Type
- Applications
- Current Assignee / Owner
- STRYKER CORP
- Filing Date
- 2021-01-13
- Publication Date
- 2026-07-16
AI Technical Summary
Existing navigation-assisted surgical systems lack effective methods to monitor and correct deviations between the intended surgical instrument trajectory and actual tool movement relative to the patient's anatomy, potentially leading to inaccurate procedures.
A navigation system that monitors the instrument tool tip's position relative to the bone, determines a tool-to-bone offset, and triggers alerts or power cutoffs when deviations exceed predefined magnitudes, using a localizer coordinate system for precise alignment.
Enhances surgical precision by providing real-time feedback and corrective actions to ensure the instrument remains within predefined proximity to the bone, thereby improving procedural accuracy and safety.
Smart Images
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Abstract
Description
comparing the monitored motor operation to the defined motor operation; determining a contact time between the instrument tool tip and the bone when the monitored motor operation deviates from the defined first motor operation; determining, with the navigation system at the contact time, a tool-to-bone offset as a distance between the instrument tool tip and a surface of the bone in the localizer coordinate system; and triggering an action when the tool-to-bone offset exceeds a predefined magnitude. 2021209063 16 Jun 2026 VIII. The method of clause VII, wherein triggering an action comprises one of sounding an audible alert, displaying a visual alert, activating a tactile alert, cutting off power to the surgical instrument, or combinations thereof. IX. The method of clause VII, wherein the predefined magnitude is 0.5 millimeters. X. The method of clause VII, further comprising displaying, on a display device, the determined tool-to-bone offset. XI. The method of clause VIII, wherein monitoring the position of the instrument tool tip relative to the bone comprises tracking the instrument location of the instrument tool tip and the bone location of the bone during the medical procedure; the method further comprising detecting, with the navigation system, each occurrence during the operation of the monitored position of the instrument tool tip being in contact with the surface of the bone and logging a series of tool-to-bone offset values determined during the medical procedure upon each occurrence. XII. The method of clause VII, further comprising displaying, on a display device, a series of tool-to-bone offsets as a serially updating value. XIII. The method of clause XII, further comprising defining a first level magnitude and a second level magnitude, wherein the step of displaying the determined tool-to-bone offset comprises displaying the offset in a first color when the offset is less than the first level magnitude, displaying the offset in a second color, different from the first color, when the offset is between the first level and the second level magnitude; and displaying the offset in a third color, different from the first and the second colors, when the offset is greater than the second level magnitude. XIV. The method of clause XIII, wherein the predefined magnitude for triggering an action is equal to the second level magnitude. 2021209063 16 Jun 2026 XV. The method of clause XIII, wherein the predefined magnitude for triggering an action is greater than the second level magnitude. XVI. The method of clause XIII, further comprising defining a third level magnitude, the method further comprising disabling power from the controller to the surgical instrument when the tool-to-bone offset is greater than the third level magnitude. XVII. The method of clause VII, further comprising prompting a user to enter a value for the predefined magnitude. XVIII. The method of clause XVII, further comprising disabling power from the controller to the surgical instrument when the tool-to-bone offset is greater than the predefined value. XIX. The method of clause XII, further comprising displaying the series of tool-to-bone offsets as a chart of offset values over time. XX. The method of clause VII , wherein triggering an action comprises prompting a user to update a model of the bone. XXI. The method of clause XX, wherein updating the model of the bone comprises contacting a resected surface of the bone with the instrument tool tip while power is disabled from the controller to the surgical implement. XXII. A method of operating a surgical system during a surgical operation to verify a tracking registration, the surgical system including a navigation system including a localizer having a localizer coordinate system, an instrument tracker coupled to a surgical instrument, the surgical instrument including a tool tip, a patient tracker coupled to a patient’s anatomy, a control console in communication with the localizer, the control console in communication with data representing the surgical instrument and data representing the patient’s anatomy, the method comprising: 2021209063 16 Jun 2026 tracking, with the navigation system, the surgical instrument and the anatomy and storing, with the control console, first data representing the tracked surgical instrument and second data the tracked anatomy in a common coordinate system; determining the tool tip is within a predefined proximity to the tracked anatomy based on the first data representing the tracked surgical instrument and second data representing the tracked anatomy; determining the tool tip does not depart the predefined proximity by more than a predefined magnitude over a predefined duration; determining an offset distance based on the first data representing the tracked surgical instrument and the second data representing the tracked anatomy; comparing the offset distance to a predefined threshold; and triggering an action when the offset distance is greater than the predefined threshold. XXIII. The method of clause XXII, further comprising prompting a user to verify a tracking registration by one of displaying a prompt on a display; sounding an audible alert; generating a haptic sensation; or combinations thereof. XXIV. The method of clause XXII, wherein determining the tool tip is within a predefined proximity to the anatomy includes defining a surface area of the anatomy not to be resected, and determining the tool tip is within a predefined proximity to the defined surface area. XXV. The method of clause XXII, wherein the offset distance is defined as a magnitude of minimum separation between the tool tip and the tracked anatomy in the common coordinate system, or as a magnitude of greatest overlap between the tool tip and the tracked anatomy in the common coordinate system. XXVI. The method of clause XXII, wherein determining the tool tip is within a predefined proximity to the tracked anatomy includes the surgical instrument positioned at a first pose with respect to the tracked anatomy, the surgical instrument defining a first proximal point of the tool tip and wherein determining the offset distance includes determining a first offset distance; 2021209063 16 Jun 2026 the method further comprising determining the tool tip is within a predefined proximity to the tracked anatomy including the surgical instrument positioned at a second pose with respect to the tracked anatomy, the surgical instrument defining a second proximal point of the tool tip and wherein determining the offset distance includes determining a second offset distance. XXVII. The method of clause XXVI, wherein comparing the offset distance to a predefined threshold includes comparing the first offset distance to the predefined threshold, and comparing the second offset distance to the predefined threshold, and wherein initiating an action includes initiating an action when the first offset distance, the second offset distance, or both the first and second offset distances are greater than the predefined threshold. XXVIII. The method of clause XXVI, wherein the surgical instrument includes an elongated aspect terminating at the tool tip, the elongated aspect defining a longitudinal axis extending substantially parallel to the elongated aspect; and wherein the second proximal point is at least 90° from the first proximal point relative to a rotation about a centerline. XXIX. The method of clause XXVI, wherein the surgical instrument includes the tool tip having a spherical aspect defining a centerpoint, wherein the second proximal point is at least 90° away from the first proximal point relative to a rotation about the centerpoint. XXX. The method of clause XXVI, wherein determining the tool tip is within a predefined proximity to the tracked anatomy includes the surgical instrument positioned at a third pose with respect to the tracked anatomy, the surgical instrument defining a third proximal point, the third proximal point being different from the first proximal point and different from the second proximal point, and wherein determining the offset distance further includes determining a third offset distance. XXXI. The method of clause XXX, wherein comparing the offset distance to a predefined threshold includes comparing the first offset distance to the predefined threshold, comparing the second offset distance to the predefined threshold, and comparing the third offset distance to the predefined threshold, and wherein initiating an action includes initiating an action when the first 2021209063 16 Jun 2026 offset distance, the second offset distance, the third offset distance or combinations thereof are greater than the predefined threshold. XXXII. The method of clause XXX, wherein the surgical instrument includes an elongated aspect terminating at the tool tip, the elongated aspect defining a longitudinal axis extending substantially parallel to the elongated aspect; and wherein the second proximal point is at least 90° from the first proximal point relative to a rotation about the longitudinal axis, and wherein the third proximal point is at least 90° away from the first and second proximal points relative to a rotation about the longitudinal axis. XXXIII. The method of clause XXX, wherein the surgical instrument includes the tool top having a spherical aspect defining a centerpoint, wherein the second proximal point is at least 90° away from the first proximal point relative to a rotation about the centerpoint and wherein the third proximal point is at least 90° away from the first and second proximal points relative to a rotation about the centerpoint. XXXIV. The method of any of the preceding clauses XXII - XXXIII, wherein triggering an action includes one of sounding an audible alert, displaying a visual alert, activating a tactile alert, cutting off power to the surgical instrument or combinations thereof. XXXV. The method of any of the preceding clauses XXII - XXXIV, wherein the predefined threshold includes a first predefined threshold, and a second predefined threshold, and wherein triggering an action of the navigation system includes triggering a first action when the offset distance is greater than the first predefined threshold but less than the second predefined threshold, and triggering a second action when the offset distance is greater than the second predefined threshold, wherein the first action includes one of sounding a first audible alert, displaying a first visual alert, activating a first tactile alert or combinations thereof and wherein the second action includes one of sounding a second audible alert, displaying a second visual alert, activating a second tactile alert or combinations thereof. 2021209063 16 Jun 2026 XXXVI. A method of providing navigation guidance for a surgical procedure, the method comprising: registering a patient’s anatomy in a common coordinate system, the patient’s anatomy including at least a first bone and a second bone; registering a surgical instrument in the common coordinate system; tracking the patient’s anatomy and the surgical instrument with the navigation system during operation of the surgical instrument on the first bone of the patient’s anatomy; determining an offset distance according to claim 1 with respect to the second bone; and tracking the patient’s anatomy and the surgical instrument with the navigation system during operation of the surgical instrument on the second bone of the patient’s anatomy. XXXVII. A method of performing a surgical operation, the method comprising: coupling a patient tracker to a patient’s anatomy; coupling an instrument tracker to a surgical instrument, the surgical instrument including a tool tip; operating a navigation system to register the instrument tracker and the patient tracker in a common coordinate system and to track the surgical instrument and the patient’s anatomy; pausing the tool tip in contact with the anatomy for a predefined duration to initiate a registration verification; wherein the navigation system is configured to determine an offset distance based on the tracked surgical instrument and the tracked patient’s anatomy; and evaluating the offset distance against a predefined threshold. XXXVIII. The method of clause XXXVII, wherein the navigation system is configured to trigger an action when the offset distance is greater than the predefined threshold, wherein the action includes one of sounding an audible alert, displaying a visual alert, activating a tactile alert, cutting off power to the surgical instrument or combinations thereof. 2021209063 16 Jun 2026 XXXIX. The method of clause XXXVIII, further comprising providing an input to the navigation system to terminate the triggered action. XXXX. The method of clause XXXVII, wherein pausing the tool tip in contact with the anatomy includes pausing the tool tip in contact with a first anatomy contact point at a first time, the surgical instrument in a first pose and a first proximal point of the tool tip in contact with the first anatomy contact point, the method further comprising pausing the tool tip in contact with a second anatomy contact point at a second time, the surgical instrument in a second pose and a second proximal point of the tool tip in contact with the first anatomy contact point; and wherein the navigation system is configured to determine a first offset distance based on the first anatomy contact point and the first proximal point, and to determine a second offset distance based on the second anatomy contact point and the second proximal point. XXXXI. The method of clause XXXX, wherein evaluating the offset distance includes one of evaluating the first offset distance against the predefined threshold; evaluating the second offset distance against the predefined threshold, or combinations thereof. XXXXII. The method of clause XXXX, further comprising calculating a threedimensional offset value based on the first offset distance and the second offset distance, and a geometric relationship between the first proximal point and the second proximal point on the tool tip; and wherein evaluating the offset distance includes comparing the three-dimensional offset value to a predefined three-dimensional offset threshold. XXXXIII. The method of clause XXXVII, wherein the patient’s anatomy includes a first bone and a second bone; the method further comprising: operating the surgical instrument in application to the first bone; operating the surgical instrument in application to the second bone; and wherein pausing the tool to initiate a registration verification is performed in contact with the second bone subsequent to operating the surgical instrument in application to the first bone and prior to operating the surgical instrument in application to the second bone.
Claims
1. A surgical system comprising:a surgical instrument having a variable speed motor and a tool tip;a controller for providing power to the surgical instrument, the controller operable to monitor a motor operation of the instrument, the controller comprising a processor and a memory, the memory operable to store information, including information representing the motor operation of the instrument;an instrument tracker coupled to the instrument;a patient tracker to be coupled to a bone; anda navigation system comprising a localizer;the navigation system operable to store information representing the surgical instrument, and information representing the bone, in a virtual space;the localizer operable to register a location of the instrument tracker and a location of the patient tracker relative to a localizer coordinate system, and to gather information about the location of the instrument and the bone in cooperation with the instrument tracker and the patient tracker, respectively; andthe navigation system operable to track the location of the instrument and the location of the bone in the virtual space based on information gathered by the localizer;wherein the controller and the navigation system are in electronic communication and configured to cooperate to:determine, based on a change in the motor operation, a time of contact between the tool tip and the bone; anddetermine, at the time of contact, a tool-to-bone offset as a distance between the tracked location of the tool tip and the tracked location of the bone.
2. The surgical system of claim 1, wherein monitoring the motor operation comprises one of monitoring a power level, a voltage level, a current level, or combinations thereof, and wherein the motor operation comprises a first motor operation when operated while the tool tip is not in contact with bone and a second motor operation, different from the first motor operation, when operated while the tool tip is in contact with bone.2021209063 16 Jun 20263. The surgical system of any one of claims 1-2, further comprising an alert device, wherein the controller and the navigation system are further configured to trigger an action when the tool-to-bone offset is greater than a predefined magnitude.
4. The surgical system of claim 3, wherein triggering the action comprises one of sounding an audible alert, displaying a visible alert, activating a tactile alert, cutting off power to the surgical instrument, or combinations thereof.
5. The surgical system of claim 3 or 4, wherein the alert device is a footswitch, wherein the footswitch is operable to generate a vibration; and wherein the action is a vibration of the footswitch.
6. The surgical system of any one of claims 3-5, wherein the action comprises prompting a user to update a model of the bone by contacting a resected surface of the bone with the tool tip while power is disabled from the controller to the surgical instrument.
7. The surgical system of any one of claims 3-6, wherein the predefined magnitude is 0.5 millimeters.
8. The surgical system of any one of claims 1-7, wherein the controller and the navigation system are configured to trigger a first action when the tool-to-bone offset reaches or exceeds a first predefined magnitude and a second action, different from the first action when the tool-to-bone offset reaches or exceeds a second predefined magnitude greater than the first predefined magnitude.
9. The surgical system of claim 8, wherein the first action is a visible alert, and the second action is a combination of visual and audible alerts.
10. The surgical system of claim 8 or 9, wherein the controller and the navigation system are configured to disable power from the controller to the surgical instrument when the2021209063 16 Jun 2026tool-to-bone offset reaches or exceeds a third predefined magnitude greater than the first and second predefined magnitudes.
11. The surgical system of any one of claims 1-10, further comprising a display device in electronic communication with one of the controller, the navigation system, or the combination of the controller and the navigation system, and wherein the controller, the navigation system or the combination of the controller and the navigation system are further configured to cause the display device to display the determined tool-to-bone offset.
12. The surgical system of claim 11, wherein the tool-to-bone offset is displayed in a first color when the tool-to-bone offset is less than a predefined magnitude and is displayed in a second color, different from the first color, when the tool-to-bone offset is greater than the predefined magnitude.
13. The surgical system of any one of claims 1-12, wherein the controller and the navigation system are configured to cooperate to determine each occurrence of a change in motor operation during a medical procedure; determine a respective time of contact between the tool tip and the bone for each occurrence of the change in motor operation; determine, for each respective time of contact, a tool-to-bone offset; and log a series of determined tool-to-bone offsets.
14. The surgical system of claim 13, wherein the controller, the navigation system or the combination of the controller and the navigation system are further configured to cause a display device to display the series of determined tool-to-bone offsets as a serially updating value.
15. A surgical system comprising:a surgical instrument having an actuator and a tool tip;a controller for providing power to the surgical instrument, the controller operable to monitor an actuator operation of the instrument, the controller comprising a processor and a memory, the memory operable to store information, including information representing an actuator operation of the instrument;an instrument tracker coupled to the instrument;2021209063 16 Jun 2026a patient tracker to be coupled to a tissue; anda navigation system comprising a localizer;the navigation system operable to store information representing the surgical instrument, and information representing the tissue, in a virtual space;the localizer operable to register a location of the instrument tracker and a location of the patient tracker relative to a localizer coordinate system, and to gather information about the location of the instrument and the tissue in cooperation with the instrument tracker and the patient tracker, respectively;the navigation system operable to track the location of the instrument and the location of the tissue in the virtual space during operation based on information gathered by the localizer;wherein the controller and the navigation system are in electronic communication and configured to cooperate to:determine, based on a change in the actuator operation, a time of contact between the tool tip and the tissue; anddetermine, at the time of contact, a tool-to-bone offset as a distance between the tracked location of the tool tip and the tracked location of the tissue.
16. A method of navigating a surgical instrument having a variable speed motor and a tool tip relative to a bone, the method using a navigation system including a localizer, an instrument tracker coupled to the surgical instrument, a patient tracker coupled to a bone, and a controller in communication with the navigation system, the controller controlling the surgical instrument, the method comprising:gathering, with the localizer, information about a location of the instrument and the bone in cooperation with the instrument tracker and the patient tracker;monitoring, with the controller, a motor operation of the instrument during a medical procedure;tracking, with the navigation system, the location of the instrument and the location of the bone based on information gathered by the localizer;determining, with the controller and the navigation system acting in cooperation, a time of contact between the tool tip and the bone based on a change in the motor operation; and2021209063 16 Jun 2026determining, with the controller and the navigation system acting in cooperation, a tool-to-bone offset as a distance between the tracked location of the tool tip and the tracked location of the bone.
17. The method of claim 16, further comprising triggering an action when the tool-to-bone offset is greater than a predefined magnitude.
18. The method of claim 17, wherein triggering an action comprises one of sounding an audible alert, displaying a visual alert, activating a tactile alert, cutting off power to the surgical instrument, or combinations thereof.
19. The method of any one of claims 16-18, comprising displaying, on a display, the tool-to-bone offset in a first color when the tool-to-bone offset is less than a predefined magnitude and in a second color, different from the first color, when the tool-to-bone offset is greater than the predefined magnitude.
20. The method of any one of claims 16-19, comprising triggering a first action when the tool-to-bone offset reaches or exceeds a first predefined magnitude and a second action, different from the first action when the tool-to-bone offset reaches or exceeds a second predefined magnitude, different from the first predefined magnitude.