Method for controlling display of a navigation view indicating recommended entry points that change immediately

Abstract

A method for controlling the display of a navigation view for surgical navigation is described. The method includes: obtaining a planned entry point and a planned target; obtaining a current orientation of a surgical instrument; determining a current entry point; and controlling the display of a navigation view indicating at least one recommended entry point. When a distance between the planned entry point and the current entry point satisfies a predetermined condition, the recommended entry point is immediately changed from the planned entry point to the current entry point. A processor, a computer-readable medium, and a data carrier signal are also disclosed.

Description

Technical Field

[0001] The present disclosure generally relates to surgical navigation, that is, to a computer-implemented method for controlling a navigation view for surgical navigation. A processor, a computer-readable medium, and a data carrier signal are also disclosed. Background Art

[0002] During surgical navigation, the surgeon can use the surgical navigation system to help align the surgical instrument relative to the patient. To this end, the position and orientation of surgical objects such as surgical instruments and the patient can be determined as a basis for providing navigation instructions to the surgeon.

[0003] In an exemplary application of a surgical navigation system, both the surgical instrument and the patient are associated with tracking markers, wherein three-dimensional image data of the patient previously acquired, for example, by computed tomography (CT) can be registered with the patient tracking markers, and the surgical instrument is registered with the instrument tracking markers. By tracking the tracking markers of the patient and the surgical instrument, the position and orientation of both the patient and the surgical instrument can be determined, and thus the spatial relationship between the three-dimensional image data of the patient and the position and orientation of the surgical instrument can be determined.

[0004] In some surgical procedures, the surgeon needs to align the surgical instruments (e.g., shunt probes, drills, cones, stopcocks, screwdrivers, biopsy needles, etc.) relative to the patient's body by himself so that the surgical instruments are aligned with the trajectory line planned before the operation. The trajectory line planned before the operation (i.e., the planned trajectory line) is usually defined by the planned entry point and the planned target. The entry point usually defines the point where the skin of the patient's body should be cut or the point where the hole should be drilled in the patient's skull, and the surgical instruments will enter the patient's body through these positions. The entry point can define the point on the bone surface of the vertebra where the implant (e.g., pedicle screw) should be inserted. The target and the planned entry point can be defined in the patient's three-dimensional image data. Examples of such targets are target points (i.e., points in the chamber), tumors, anatomical organs to be treated, the tip position of the desired pedicle screw, etc. The target can be defined by defining points or depicting geometric structures in the three-dimensional image data.

[0005] After the planning data describing the planned entry points and targets are determined, surgical navigation may be performed during the process of displaying the previously determined spatial relationships on a screen, for example in the form of a navigation view, thereby assisting the surgeon in guiding surgical instruments to the patient.

[0006] In some cases, the surgeon may determine during the course of surgical navigation that a slightly different entry point is preferable relative to the planned entry point. In other cases, the surgeon may not be able to perfectly align the surgical instrument with the planned entry point.

[0007] Some navigation views can support two different alignment modes. In the first alignment mode, the surgical instrument is aligned with both the planned entry point and the planned trajectory line. If the trajectory line is perfectly aligned, the result is the same as Figure 3 However, in practice, typical results are similar to Figure 6 In the second alignment mode, the surgical instrument is aligned with the target only. Then the trajectory of the surgical instrument can accurately pass through the target, but may miss the planned entry point, such as Figure 5 shown.

[0008] The prior art does not provide for rapid and accurate alignment of a navigated surgical instrument for accurately and reliably reaching a planned target. Summary of the invention

[0009] There is a need for a computer-implemented method of controlling the display of a navigation view that addresses one or more of the above or other problems.

[0010] According to a first aspect, a computer-implemented method for controlling the display of a navigation view for surgical navigation is provided. The method comprises: obtaining planning data defining a planned entry point and a planned target, wherein the planned entry point and the planned target are defined in a coordinate system of a computer model of at least one anatomical object; the method further comprises: obtaining tracking data describing a current posture of a surgical instrument in the coordinate system; and determining a current entry point located on a trajectory line having a fixed spatial relationship with the surgical instrument based at least on the tracking data. The method further comprises: controlling the display of a navigation view that visualizes at least one recommended entry point, wherein when a distance between the planned entry point and the current entry point satisfies a predetermined condition, the recommended entry point is immediately changed from the planned entry point to the current entry point.

[0011] The planned entry point satisfies, for example, at least one condition selected from the following conditions: being far from a planned target; not included in the planned target; and being different from the planned target. The planned entry point may be located a predetermined distance below or a predetermined distance above an outer surface of a computer model of at least one anatomical object, for example, where the computer model is determined based on computed tomography (CT) patient image data. In one example, the planned entry point is located on the outer surface of the computer model, and the planned target is located below the outer surface of the computer model. The outer surface may correspond to a bone surface of the anatomical object.

[0012] At least one anatomical object is, for example, an anatomical organ, a bone, a limb, etc. In one example, at least one anatomical object includes: all body parts in a cross section of the patient's entire body or in the patient's entire body. The cross section may be size-limited depending on the imaging technology used. In other words, at least one anatomical object may include all anatomical objects described by patient image data. The patient image data is obtained, for example, by acquiring a medical image of the patient, and may specifically be CT patient image data or magnetic resonance (MR) patient image data. At least one anatomical object may substantially include a specific tissue type, such as bone, muscle, skin, or tendon. For example, the at least one anatomical object has a predetermined transmittance for X-rays, resulting in a predetermined range of Hounsfield values ​​in the X-ray or CT image.

[0013] The planning target is, for example, equal to or includes the target point or the outline of the enlarged anatomical target. The planning target can be a volume in a computer model, for example, a volume including or describing an anatomical object (eg, an anatomical organ, a tumor, a region of interest, etc.).

[0014] The planning data may be obtained by obtaining first data describing a planned entry point and obtaining second data describing a target. The orientation of the surgical instrument in the tracking coordinate system may be obtained by obtaining the orientation of the surgical instrument in the tracking coordinate system and transforming the orientation to the coordinate system based on a known transformation between the tracking coordinate system and the coordinate system.

[0015] The trajectory line is, for example (ie, substantially) parallel to the longitudinal axis of the surgical instrument, (ie, substantially) parallel to the insertion direction of the surgical instrument, or (ie, substantially) orthogonal to the handle of the surgical instrument.

[0016] The navigation view visualizes the recommended entry points, such as by aligning or orienting the navigation view relative to the recommended entry points.

[0017] The predetermined condition is, for example, that the distance between the planned entry point and the current entry point is less than a threshold value. The threshold value may be a predetermined value, for example, 0.5 mm, 1 mm, 1.5 mm, 3 mm or 4 mm, in particular 2 mm. The threshold value is greater than 0 mm in one example, in particular greater than 1 mm or greater than 2 mm. The threshold value may be obtained in a previous method step. The threshold value may be set by a user. For example, the threshold value is a value that depends on the spatial relationship between the planned entry point and the target. In this case, the threshold value may correspond to a specific percentage of the distance between the planned entry point and the target. The threshold value is, for example, a value that depends on the spatial relationship between the surgical instrument and at least one of the target, the current entry point and the planned entry point. The threshold value may be selected so that the user can detect instantaneous changes in the recommended entry point only from the navigation view. The threshold value may be greater than the distance described by a single pixel of the navigation view. For example, the threshold value is greater than a predetermined percentage of the width of the axis of the surgical instrument.

[0018] The navigation view can visualize the recommended entry points and the planned goals, for example by displaying the recommended entry points and the planned goals on the representation of the computer model and / or by orienting the navigation view relative to at least one of the recommended entry points and the planned goals.

[0019] The navigation view in one example has a viewing direction corresponding to a straight line between the recommended entry point and the planned destination.

[0020] The navigation view may be a bull's eye view centered on the straight line between the recommended entry point and the planned target. In another variation, the navigation view includes: a bull's eye centered on the straight line between the recommended entry point and the planned target. The bull's eye or bull's eye view may include: at least one concentric line centered on the straight line between the recommended entry point and the planned target. The at least one concentric line may be a two-dimensional line located in a plane that is orthogonal to the straight line between the recommended entry point and the planned target. The bull's eye or bull's eye view, for example, uses the straight line between the recommended entry point and the planned target as the viewing direction. In addition, or as an alternative, for the bull's eye, the navigation view may include one or more aiming lines, for example, a first aiming line that is substantially orthogonal to a second aiming line. One or more aiming lines may intersect the straight line between the recommended entry point and the planned target.

[0021] A variant of the navigation view includes visualization of the relative spatial relationship between the recommended entry points and the planned goals. The visualization of the relative spatial relationship between the recommended entry points and the planned goals is, for example, at least one of numbers, text, a bar chart, a progress bar, and the like.

[0022] For example, the navigation view includes a visualization of the relative spatial relationship between the surgical instrument and at least one destination selected from the recommended entry point and the planned target. For example, the navigation view includes a visualization of the shortest distance between the trajectory line and the planned target. The visualization of the relative spatial relationship between the surgical instrument and at least one target point is, for example, at least one of a number, text, a bar graph, a progress bar, etc.

[0023] The navigation view may include a visualization of the relationship between: the distance between the position of the surgical instrument in the coordinate system and a recommended entry point, and the distance between the recommended entry point and a target. The navigation view may include a visualization of the relationship between a first distance, where the first distance is, for example, the distance between the position of the surgical instrument in the coordinate system and one of the recommended entry point and the target, and the second distance is, for example, the distance between the recommended entry point and the target. The navigation view in one example includes: a visualization of a score determined by dividing the first distance by the second distance. The navigation view may include a visualization of a score determined by dividing the second distance by the first distance. In another example, the navigation view includes: a visualization of at least one distance selected from the first distance and the second distance.

[0024] The visualization of the relative spatial relationship, the visualization of the relationship and / or the visualization of the score is, for example, a progress bar. The progress bar can be formed concentrically around the alignment point in the navigation view. The alignment point in one example is located on a straight line between the recommended entry point and the planned target. The alignment point can be a bull's eye and / or the center of the aiming line.

[0025] In one variation, when the distance between the planned entry point and the current entry point satisfies the predetermined condition, the recommended entry point is permanently changed from the planned entry point to the current entry point.

[0026] In one variant, when the distance between the planned entry point and the current entry point no longer meets a predetermined criterion, the recommended entry point is immediately reset from the current entry point to the planned entry point. The predetermined criterion is, for example, the predetermined condition. In one example, the predetermined criterion is that the distance between the planned entry point and the current entry point is less than a limit value. The limit value defined by the predetermined criterion may be greater than a threshold value defined by the predetermined condition. The limit value may be a predetermined value, such as 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm or 3 mm. The limit value in one example is greater than 0 mm. The limit value may be obtained in a previous method step. The limit value may be set by a user. For example, the limit value is a value that depends on the spatial relationship between the planned entry point and the target. In this case, the limit value may correspond to a specific percentage of the distance between the planned entry point and the target. The limit value is, for example, a value that depends on the spatial relationship between the surgical instrument and at least one of the target, the current entry point and the planned entry point. The limit value may be selected so that the user can detect the instantaneous reset of the recommended entry point only from the navigation view. The limit value may be greater than the distance described by a single pixel of the navigation view. For example, the limit value is greater than a predetermined percentage of the width of the shaft of the surgical instrument.

[0027] According to a second aspect, a processor for a surgical navigation system is provided. The processor is configured to: obtain planning data defining a planned entry point and a planned target, wherein the planned entry point and the planned target are defined in a coordinate system of a computer model of at least one anatomical object. The processor is also configured to: obtain tracking data describing a current posture of a surgical instrument in the coordinate system; and determine a current entry point located on a trajectory line having a fixed spatial relationship with the surgical instrument based at least on the tracking data. The processor is configured to: control the display of a navigation view that visualizes at least one recommended entry point, wherein when the distance between the planned entry point and the current entry point satisfies a predetermined condition, the recommended entry point is immediately changed from the planned entry point to the current entry point.

[0028] According to a third aspect, a computer-readable medium is provided. The computer-readable medium includes a computer program, the computer program including instructions, when the program is executed by a processor, the processor is caused to execute the method according to the first aspect. For example, the computer program includes instructions, when the program is executed by the processor, the instructions cause the processor to: obtain planning data defining a planned entry point and a planned target, wherein the planned entry point and the planned target are defined in a coordinate system of a computer model of at least one anatomical object; obtain tracking data describing the current posture of a surgical instrument in the coordinate system; determine the current entry point located on a trajectory line having a fixed spatial relationship with the surgical instrument based at least on the tracking data; and control the display of a navigation view that visualizes at least one recommended entry point, wherein when the distance between the planned entry point and the current entry point meets a predetermined condition, the recommended entry point is immediately changed from the planned entry point to the current entry point.

[0029] According to a fourth aspect, there is provided a data carrier signal carrying information representing a computer program, the computer program comprising instructions which, when executed by a processor, cause the processor to perform the method of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Additional details, advantages and aspects of the present disclosure will become apparent from the following embodiments taken in conjunction with the accompanying drawings, in which:

[0031] Figure 1 A surgical navigation system is shown;

[0032] Figure 2 A method for controlling the display of a navigation view is shown;

[0033] Figure 3 a computer model showing at least one anatomy included in the patient's body with a sagittal (lateral) view of a planned entry point and a planned target;

[0034] Figure 4 showing a sagittal (side) view of the computer model and the trajectory of the surgical instrument in a first exemplary posture;

[0035] Figure 5 showing a sagittal (side) view of the computer model and a trajectory of the surgical instrument in a second exemplary posture;

[0036] Figure 6 showing a sagittal (side) view of the computer model and the trajectory of the surgical instrument in a third exemplary posture;

[0037] Figure 7showing a sagittal (side) view of the computer model and the trajectory of the surgical instrument in a fourth exemplary posture;

[0038] Figure 8 showing a perspective view of the computer model and the surgical instrument in a fifth exemplary posture;

[0039] Fig. 9 showing a navigation view utilizing the surgical instrument in a fifth exemplary posture;

[0040] Fig.10 showing a sagittal (lateral) view of the computer model indicating the viewing direction of the navigation view and a trajectory of the surgical instrument in a sixth exemplary posture;

[0041] Fig.11 showing a first example of a navigation view utilizing a surgical instrument in a sixth exemplary posture;

[0042] Fig.12 showing a sagittal (side) view of the computer model indicating the viewing direction of the navigation view and a trajectory line of the surgical instrument in a seventh exemplary posture;

[0043] Fig.13 showing a first example of a navigation view utilizing a surgical instrument in a seventh exemplary posture;

[0044] Fig.14 showing a sagittal (side) view of the computer model indicating the viewing direction of the navigation view and a trajectory line of the surgical instrument in an eighth exemplary posture;

[0045] Fig.15 showing a first example of a navigation view utilizing a surgical instrument in an eighth exemplary posture;

[0046] Fig.16 showing a sagittal (side) view of the computer model indicating the viewing direction of the navigation view and a trajectory line of the surgical instrument in a ninth exemplary posture;

[0047] Fig.17 showing a first example of a navigation view utilizing a surgical instrument in a ninth exemplary posture;

[0048] Fig.18 showing a second example of a navigation view utilizing the surgical instrument oriented in an eighth exemplary posture;

[0049] Fig.19 showing a second example of a navigation view utilizing the surgical instrument oriented in an eighth exemplary posture;

[0050] Fig. 20 showing a second example of a navigation view utilizing the surgical instrument oriented in an eighth exemplary posture;

[0051] Fig.21 showing a second example of a navigation view utilizing the surgical instrument oriented in an eighth exemplary posture;

[0052] Fig. 22 showing a second example of a navigation view utilizing the surgical instrument oriented in an eighth exemplary posture;

[0053] Fig.23 Different recommended entry points on the trajectory of the surgical instrument are shown. DETAILED DESCRIPTION

[0054] In the following description, exemplary embodiments of computer-implemented methods, processors, computer-readable media, and data-carrying signals will be described with reference to the accompanying drawings. The same reference numerals will be used to represent the same or similar structural features or method steps.

[0055] Figure 1 A surgical navigation system 100 is shown. The surgical navigation system 100 includes a processor 2 and a display 4. The surgical navigation system 100 also includes an optical tracking system 6 including an optical sensor 8 and having a first tracking coordinate system 10. The optical tracking system 6 is configured to track an optical tracker, such as an optical tracker 12 attached to a patient 14 and an optical tracker 16 attached to a surgical instrument 18.

[0056] The surgical instrument 18 includes a handle 20 and a shaft 22 having a longitudinal axis 24 that coincides with an insertion direction of the surgical instrument or a tool to be inserted through the shaft 22 of the surgical instrument 18 .

[0057] The surgical navigation system 100 also includes an electromagnetic tracking system 26, which includes a field generator 28 and a position determination unit 30. The position determination unit 30 is configured to determine the position of the electromagnetic sensor relative to the field generator 28 in a second tracking coordinate system 32. For example, the electromagnetic sensor 34 is attached to the patient 14, and another electromagnetic sensor is attached to the surgical instrument 18 (not shown). The position determination unit 30 can be included in the processor 2 or implemented by the processor 2. It is noted that the surgical navigation system 100 can include both the optical tracking system 6 and the electromagnetic tracking system 26, or only one of them.

[0058] The patient image data 36 in the image data coordinate system 38 may be stored in a storage unit (not shown) and / or obtained by the processor 2. A computer model of at least one anatomy may be determined by the processor 2 (e.g., a processor in the image data coordinate system 38) based on the patient image data 36. A registration may be performed to derive a transformation between the position and orientation of the optical tracker 12 and the image data coordinate system 38. Alternatively or additionally, a registration may be performed to derive a transformation between the position and orientation of the electromagnetic tracker 34 and the image data coordinate system 38. This enables the processor 2 to determine the relevance of the patient image data 36 to the current position and orientation of the patient 14. The surgical instrument 18 may also be tracked to determine and display a navigation view indicating the relative spatial relationship between the surgical instrument 18 and the patient 14.

[0059] The navigation view may show a representation of the computer model registered with respect to the patient 14 and a representation of the surgical instrument 18. The determination of the navigation view and the control of the navigation view to be displayed on the display 4 may be performed by the processor 2. The navigation view is configured to assist the surgeon during surgical navigation.

[0060] Figure 2 A flow chart showing a method for controlling the display of a navigation view is shown. The method may be executed by the processor 2 of the surgical navigation system 100 .

[0061] The method comprises: a step 40 of obtaining planning data. The planning data describes a planning entry point in a coordinate system of a computer model of at least one anatomical object. The planning entry point is, for example, located on an outer surface of the computer model of a patient's body. The patient's body is the body of the patient 14. The outer surface of the computer model of at least one anatomical object may represent a bone surface of at least one anatomical object. The planning data also describes a planning target in the coordinate system of the computer model. The planning target is, for example, located below the outer surface of the computer model. The planning target may be an anatomical object included in the patient's body and identified in the patient image data 36. The planning target may include or be equivalent to a planning target point. The coordinate system of the computer model is, in one example, equivalent to the image data coordinate system 38.

[0062] The method comprises a further step 42 of obtaining tracking data. The tracking data describes a current pose of the surgical instrument 18 in the coordinate system. The current pose comprises at least one of the following: a current position (also referred to as a corresponding position) and a current orientation (also referred to as a corresponding orientation) of the surgical instrument 18. The current orientation describes the alignment of the surgical instrument 18 in the coordinate system, for example, the three-dimensional coordinates of the axis 24. The current position of the surgical instrument 18 can be described by a point on the axis 24 or by three-dimensional coordinates in the coordinate system.

[0063] In the case where the optical tracking system 6 determines the pose of the surgical instrument 18 by tracking the optical tracker 16 in the first tracking coordinate system 10, the known transformation between the first tracking coordinate system 10 and the coordinate system can be used to determine the current pose of the surgical instrument 18 in the coordinate system. Such a known transformation can be obtained by performing registration as described above.

[0064] In addition to or alternatively to the optical tracking system 6 for tracking the patient 14, an electromagnetic tracking system 26 may also be used for this purpose. In the case where the electromagnetic tracking system 26 determines the posture of the surgical instrument 18 by tracking the electromagnetic tracker 34 in the second tracking coordinate system 32, a known transformation between the second tracking coordinate system 32 and the coordinate system may be used to determine the current posture of the surgical instrument 18 in the coordinate system. Such a known transformation may be obtained by performing a registration as described above. In the following, all (i.e., relative) positions and orientations described refer to (i.e., relative) positions and orientations in a coordinate system. It should be clear that the (i.e., relative) positions and orientations may alternatively be described in different coordinate systems, and a transformation may be used to transform the coordinate system to a different coordinate system.

[0065] The method includes a step 44 of determining a current entry point based on the tracking data. The current entry point is a calculation of where the surgical instrument would enter the at least one anatomy if the surgical instrument were inserted into the at least one anatomy starting from the current posture. The current entry point is located on a trajectory line that has a fixed spatial relationship with the surgical instrument 18.

[0066] The current entry point in one example is located on the distal (front) end of the surgical instrument. In this case, no trajectory needs to be determined, and the tracking data may describe only the position of the surgical instrument 18 in the current posture. Additionally or alternatively, the current entry point may be located on the outer surface of the computer model. Additionally or alternatively, the current entry point may be the point on the trajectory of the surgical instrument that is closest to the planned entry point.

[0067] In case the current entry point is far from the surgical instrument, the method may include determining trajectory data describing a trajectory of the surgical instrument 18. The trajectory is determined, for example, based on tracking data describing at least one orientation of the surgical instrument 18 in the current posture. The trajectory is a straight line defined in a coordinate system and has a fixed spatial relationship with the surgical instrument 18. According to one example, the trajectory is parallel to the longitudinal axis 24 of the surgical instrument 18 or coincides with the longitudinal axis 24 of the surgical instrument 18. Additional data may be considered to determine the trajectory data, for example, geometric data describing the fixed spatial relationship.

[0068] The method also includes: a step 46 of controlling the display of a navigation view. The navigation view visualizes at least one recommended entry point. For example, the navigation view visualizes the recommended entry point by being a view aligned or oriented relative to the recommended entry point. The viewing direction of the navigation view can be determined based on the recommended entry point, so that the navigation view visualizes the recommended entry point. The navigation view can also visualize the planned target. In one example, the navigation view is a bull's-eye view centered on a straight line between the recommended entry point and the planned target, and with the straight line between the recommended entry point and the target as the viewing direction. In different examples, the navigation view shows a perspective view of a three-dimensional computer model of at least one anatomical object included in the body of the patient 14, in which the recommended entry point is highlighted.

[0069] When the distance between the planned entry point and the current entry point located on the trajectory line satisfies a predetermined condition, the recommended entry point is immediately changed from the planned entry point to the current entry point. The predetermined condition is, for example, that the distance between the planned entry point and the current entry point is less than a threshold value. The threshold value may be a predetermined value greater than 0 mm and less than 5 mm, for example, 2 mm. For example, the threshold value is a value that depends on the spatial relationship between the planned target point and the target. In this case, the threshold value may correspond to a specific percentage of the distance between the planned target point and the target.

[0070] In the following, refer to Figures 3 to 23 Describes the operations that can be performed by processor 2 Figure 2 Details of the method.

[0071] Figure 3 A sagittal (side) view of a computer model of a patient's skull is shown, along with a planned entry point 48 and a planned target 50. A target point 52 is also shown. The target point 52 may be selected by a user during the planning of the target 50, or may be automatically determined after the target 50 has been planned (e.g., outlined on the display 4 by a surgeon). In the latter case, the target point 52 is determined, for example, as the center point of the target 50 and / or as the point inside the target 50 that is farthest from the contour or surface of the target 50. The target point 52 may be located on the outer surface of the planned target 50. A planned trajectory line 54 extending between the planned entry point 48 and the planned target 50 (in the example shown, between the planned entry point 48 and the planned target point 52) ​​may also be determined based on the planning data. The planned trajectory line 54 may be automatically determined based on the planned entry point 48 and the planned target 50. Figure 3 The shown views may be determined based on planning data only, ie, the planning data may include or be derived from the patient image data 36. In another example, Figure 3 The views shown are determined based on the patient image data 36 and the planning data.

[0072] Figure 4 A sagittal (side) view of the computer model and an actual or current trajectory 56 of the surgical instrument 18 in a first exemplary posture are shown. The trajectory 56 may be determined based on the tracking data and has a fixed spatial relationship with the surgical instrument 18. The trajectory 56 is therefore an indication of the current posture of the surgical instrument 18, wherein Figure 4 The current posture in is a first exemplary posture. The target point 52 in this example is located on the planned target 50. The view shown represents an ideal alignment of the surgical instrument 18 relative to the patient 14. Specifically, the trajectory line 56 of the surgical instrument 18 passes through the planned entry point 48 and reaches the planned target point 52. In this case, the current posture of the surgical instrument 18 perfectly fits the planned target point 52 and the planned entry point 48. In other words, the trajectory line 56 coincides with the planned trajectory line 54.

[0073] Figure 5 A sagittal (side) view of the computer model and the actual or current trajectory 56 of the surgical instrument 18 in a second exemplary posture are shown. The second posture orientation results in a trajectory 56 that extends through the planned entry point 48 but does not pass through the planned target point 52. The trajectory 56 in this example still reaches the target 50, although this may not be the case if the target 50 is smaller or positioned differently. This alignment of the surgical instrument 18 relative to the patient is disadvantageous because if the surgeon causes the surgical instrument 18 to follow the trajectory 56, the surgical instrument 18 will miss the target point 52.

[0074] Figure 6 A sagittal (side) view of the computer model and a trajectory line 56 of the surgical instrument 18 in a third exemplary posture are shown. The third exemplary posture results in the trajectory line 56 extending substantially parallel to the planned trajectory line 54, although not extending through the planned entry point 48 or the planned target point 52, the trajectory line 56 reaches the target 50. This alignment of the surgical instrument 18 relative to the patient is disadvantageous because if the surgeon causes the surgical instrument 18 to follow the trajectory line 56, the surgical instrument 18 will miss the target point 52.

[0075] Figure 7A sagittal (side) view of the computer model and a trajectory line 56 of the surgical instrument 18 in a fourth exemplary posture are shown. The fourth exemplary posture results in the trajectory line 56 extending to the planned target point 52, but not extending through the planned entry point 48. If the surgeon causes the surgical instrument 18 to follow the trajectory line 56, the target point 52 will be reached by the surgical instrument 18. Because the planned target point 52 is much more important than the planned entry point 48, this alignment of the surgical instrument 18 relative to the patient is acceptable in most cases. For example, the planned trajectory line 54 can be planned so that the planned trajectory line 54 avoids important anatomical structures. Therefore, the trajectory line 56 should not deviate too much from the planned trajectory line 54. For this reason, in the event that the distance between the planned entry point 48 and the current entry point located on the trajectory line 56 satisfies a predetermined condition (e.g., falls below a predetermined threshold), Figure 7 The trajectory 56 shown is acceptable.

[0076] Figure 8 A perspective view of a computer model is shown in which a planned trajectory line 54 and a representation 58 of the front end (also referred to as the distal end) of the surgical instrument 18 are shown. The planned entry point 48 is visualized by the intersection between the planned trajectory line 54 and a circular plane 59 tangent to the outer surface of the computer model. The surgical instrument 18 in this case is in a fifth exemplary posture. The orientation and position of the surgical instrument 18 in the fifth exemplary posture are known in the coordinate system. This enables the display of the representation 58 on the computer model. As can be seen, the front end of the surgical instrument 18 is away from the planned trajectory line 54 and therefore also away from the planned target point 48. In addition, there is a large angle between the trajectory line 56 and the planned trajectory line 54. This results in a large distance between the trajectory line 56 and the planned target point 52 (not shown).

[0077] Preferably, Figure 8 The perspective view shown is oriented so that it represents the surgeon's current viewing direction of the patient 14. The current viewing direction can be determined by tracking the surgeon's position relative to the patient 14 using both or one of the tracking system 6 and the tracking system 26. Alternatively or additionally, the current viewing direction can be determined based on the fifth exemplary posture of the surgical instrument 18. In another variation, the current viewing direction is obtained based on viewing direction information input by the user. In one variation, Figure 8 The perspective view and navigation view shown Figure 1 or as a navigation view.

[0078] Fig. 9An example of a navigation view using surgical instrument 18 being in a fifth exemplary posture is shown. In this case, the navigation view is determined by processor 2 based on tracking data describing the fifth exemplary posture of surgical instrument 18, which includes the orientation and position of surgical instrument 18 in the coordinate system.

[0079] The navigation view in this example is a bull's eye view with the straight line extending between the planned entry point 48 and the planned target point 52 as the viewing direction. The navigation view in this example includes a pair of sight lines 61 and 63. The first sight line 61 extends substantially vertically, while the second sight line 63 extends substantially horizontally. It should be noted that the bull's eye view also includes two circles formed concentrically around the alignment point. The alignment point coincides with the intersection of the two sight lines 61 and 63. In other examples, the navigation view does not include such a circle, but includes at least one of the sight line 61 and the sight line 63.

[0080] A straight line defining the viewing direction 64 of the navigation view extends between the planned entry point 48 and the planned target point 52. The bull's-eye view is centered on this straight line. The alignment point is located on this straight line.

[0081] In addition, a representation 58 of the end of the surgical instrument 18 is shown. The representation 58 in this case is a two-dimensional projection of the end of the surgical instrument 18 onto a plane perpendicular to the viewing direction. In addition, an indication 60 of the distance between the distal end of the surgical instrument 18 and the target 50 (i.e., the target point 52) ​​and an indication 62 of the minimum distance between the trajectory line 56 and the target 50 (i.e., the target point 52) ​​are shown. Another indication of the relative spatial relationship between the recommended entry point (in this example, the planned entry point 48) and the target 50 may also be shown.

[0082] based on Fig. 9 It is clear that the trajectory line 56 of the surgical instrument 18 in the fifth exemplary orientation is unfavorable. The distance between the current entry point located on the trajectory line 56 of the surgical instrument 18 in the fifth exemplary orientation and the planned entry point 48 does not satisfy the predetermined condition. Therefore, with the surgical instrument 18 in the fifth exemplary posture, the navigation view to be displayed controlled by the processor 2 is a bull's eye view centered on the straight line extending between the planned entry point 48 and the planned target point 52.

[0083] By continuously tracking the surgical instrument 18, the navigation view can be controlled by the controller 2 in near real time. Controlling the navigation view preferably includes: determining the navigation view; and triggering the display 4 to display the determined navigation view. Therefore, the surgeon can be provided with the latest navigation view corresponding to the current posture of the surgical instrument.

[0084] Fig.10 , Fig.12 , Fig.14 and Fig.16 Different relative positions are shown between surgical instrument 18, planned entry point 48, and planned target 50. These figures depict sequential movement of surgical instrument 18, ie, sequential movement from the sixth exemplary posture via the seventh exemplary posture and the eighth exemplary posture to the ninth exemplary posture. Fig.11 , Fig.13 , Fig.15 and Fig.17 The control by the processor 2 is shown for Fig.10 , Fig.11 , Fig.12 and Fig.14 The relative positional relationship shown in FIG. 4 is visualized in a corresponding navigation view on the display 4. In other words, Fig.11 , Fig.13 , Fig.15 and Fig.17 Continuous changes of the navigation view corresponding to continuous changes in the posture of surgical instrument 18 from the sixth exemplary posture via the seventh exemplary posture and the eighth exemplary posture to the ninth exemplary posture are shown. Fig.11 , Fig.13 , Fig.15 and Fig.17 The representation 58 in is a two-dimensional projection of the distal end of the surgical instrument 18 onto a plane perpendicular to the viewing direction of the navigation view.

[0085] Fig.10 A sagittal (side) view of the computer model is shown indicating a viewing direction 64 of the navigation view. Also shown is a representation 58 of the distal end of the surgical instrument 18 in a sixth exemplary posture. The representation 58 can be determined by the processor 2 based on tracking data, which describes the sixth exemplary posture of the surgical instrument 18 in the coordinate system by describing the corresponding position and orientation of the surgical instrument 18 in the coordinate system. It can be seen that in this example, a straight line extending between the planned target point 48 and the planned target point 52 of the target 50 is used as the viewing direction of the navigation view. In this case, according to the method described herein, as Fig.11 The display of the first example of the navigation view shown may be controlled by the processor 2 .

[0086] Fig.11A first example of a navigation view utilizing a surgical instrument 18 that is in a sixth exemplary posture is shown. In this case, the navigation view may be determined by the processor 2 based on tracking data that describes the sixth exemplary posture of the surgical instrument 18 in the coordinate system by describing the corresponding position and orientation of the surgical instrument 18 in the coordinate system. As can be seen based on the indication 62, the trajectory line 56 of the surgical instrument 18 in the sixth exemplary posture is closer to the target point 52 than the trajectory line 56 of the surgical instrument 18 in the fifth exemplary posture. The distance between the current entry point located on the trajectory line 56 of the surgical instrument 18 in the sixth exemplary posture and the planned entry point 48 does not satisfy a predetermined condition. Therefore, with the surgical instrument 18 in the sixth exemplary posture, the navigation view to be displayed controlled by the processor 2 in this example is a bullseye view centered on a straight line extending between the planned entry point 48 and the planned target point 52, as shown in FIG. Fig.11 shown.

[0087] Fig.12 A sagittal (side) view of the computer model is shown indicating a viewing direction 64 of the navigation view. Also shown is a representation 58 of the distal end of the surgical instrument 18 in a seventh exemplary posture. The representation 58 can be determined by the processor 2 based on tracking data, which describes the seventh exemplary posture of the surgical instrument 18 in the coordinate system by describing the corresponding position and orientation of the surgical instrument 18 in the coordinate system. The distance between the current entry point 66 and the planned entry point 48 located on the trajectory line 56 of the surgical instrument 18 in the seventh exemplary posture satisfies a predetermined condition. In the example shown, the current entry point 66 is located on the trajectory line 56, on the distal end of the surgical instrument 18, and on the outer surface of the computer model. It can be seen that in this example, the straight line extending between the current entry point 48 and the planned target point 52 of the target 50 is used as the viewing direction of the navigation view. In this case, according to the method described herein, as Fig.13 The display of the example of the navigation view shown may be controlled by processor 2 .

[0088] Fig.13 An example of a navigation view utilizing the surgical instrument 18 being in the seventh exemplary posture is shown. In this case, the navigation view may be determined by the processor 2 based on tracking data that describes the seventh exemplary posture of the surgical instrument 18 in the coordinate system by describing the corresponding position and orientation of the surgical instrument 18 in the coordinate system. The distance between the current entry point 66 and the planned entry point 48 located on the trajectory line 56 of the surgical instrument 18 in the seventh exemplary posture satisfies a predetermined condition. Therefore, with the surgical instrument 18 in the seventh exemplary posture, the navigation view to be displayed controlled by the processor 2 in this example is a bull's-eye view centered on a straight line extending between the current entry point 66 and the planned target point 52, as shown in FIG. Fig.13Another indication of the relative spatial relationship between the recommended entry point (in this example, current entry point 66) and target 50 may also be shown.

[0089] based on Figures 10 to 13 It will be clear that the navigation view controlled by the processor 2 to be displayed on the display 4 changes based on the distance between the current entry point and the planned entry point 48 meeting the predetermined condition. Specifically, in the example shown, the viewing direction 64 of the navigation view is immediately changed from a first viewing direction to a second viewing direction, wherein the first viewing direction coincides with a straight line extending between the planned entry point 48 and the planned target point 52, and the second viewing direction coincides with a straight line extending between the current entry point 66 and the planned target point 52. Therefore, once the surgical instrument is positioned sufficiently close to the planned entry point 48, the viewing direction 64 of the navigation view can be immediately changed, thereby allowing improved navigation of the surgical instrument 18. For example, the surgeon does not need to perfectly reach the planned entry point 48 by positioning the surgical instrument 18 on the patient's body. A smaller deviation that is considered acceptable can therefore be defined as a threshold value of the predetermined condition.

[0090] When the general Fig.11 The navigation view is Fig.13 , it can be seen that the representation 58 jumps from a position away from the center of the bull's eye to the center of the bull's eye. This is because in this example of the navigation view, the viewing direction 64 changes immediately when the distance between the current entry point 66 and the planned entry point 48 satisfies the predetermined condition. When it is determined that the distance between the current entry point 66 and the planned entry point 48 satisfies the predetermined condition, an instantaneous (e.g., sudden, rapid, direct, or single-step) change of the recommended entry point occurs. The above distance can be continuously calculated by continuously tracking the posture of the surgical instrument 18 and the patient 14 and determining their corresponding orientation and / or position in the coordinate system. Once the calculated distance satisfies the predetermined condition, the recommended entry point changes immediately.

[0091] Before you move a perspective view (for example, Figure 8 In the case where the perspective view described above is used as a navigation view or in combination with the navigation view, when the distance between the current entry point 66 and the planned entry point 48 meets the predetermined condition, the visualized recommended entry point can also be immediately changed from the planned entry point 48 to the current entry point 66. The current entry point 66 can then be visualized by visually highlighting the current entry point 66 in the perspective view or by showing the trajectory line 56 intersecting a plane tangent to the outer surface of the computer model and orthogonal to the trajectory line 56.

[0092] After the recommended entry point is immediately changed, when the distance between the planned entry point 48 and the current entry point 48 no longer satisfies a predetermined criterion (e.g., the predetermined condition), the recommended entry point may be reset from the current entry point 66 to the planned entry point 48. Alternatively, when the distance between the planned entry point 48 and the current entry point 66 satisfies the predetermined condition, the recommended entry point may be permanently changed from the planned entry point 48 to the current entry point 66.

[0093] Fig.12 A sagittal (side) view of the computer model is shown indicating the viewing direction 64 of the navigation view. Also shown is a representation 58 of the tip of the surgical instrument 18 in an eighth exemplary pose. The representation 58 can be determined by the processor 2 based on the tracking data, which describes the eighth exemplary pose of the surgical instrument 18 in the coordinate system by describing the corresponding position and orientation of the surgical instrument 18 in the coordinate system. Fig.14 The current entry point 66 is the same as Fig.12 Therefore, the distance between the current entry point 66 and the planned entry point 48 on the trajectory line 56 of the surgical instrument 18 in the eighth exemplary posture satisfies the predetermined condition, and, when the surgical instrument 18 is in the eighth exemplary posture, the navigation view to be displayed controlled by the processor 2 may be a bull's eye view centered on the straight line extending between the current entry point 66 and the planned target point 52. It can be seen that the trajectory line 56 is aligned with the viewing direction 64 and coincides with the straight line between the current entry point 66 and the target point 52.

[0094] To guide the surgeon to move the surgical instrument 18 so that the trajectory line 56 is aligned with a straight line extending between the current entry point 66 and the planned target point 52, the control Fig.13 After alignment, you can control Fig.15 's navigation view for display.

[0095] Fig.15 An example of a navigation view with the surgical instrument 18 being in an eighth exemplary posture is shown. As can be seen, the indication 58 is centered on the center of the bull's-eye view. In other words, the viewing direction 64 of the bull's-eye view corresponds to the orientation direction of the longitudinal axis 24 of the shaft 22 of the surgical instrument 18, the tip of which is shown as indication 58. Since the trajectory line 56 reaches the planned target point 52 in this case, the indication 62 describes a deviation of 0 mm. The indication 60 still shows a value of -38.1 mm as the distance between the end of the surgical instrument 18 and the target point 52 in this case.

[0096] Fig.12A sagittal (side) view of the computer model indicating the viewing direction 64 of the navigation view is shown. Also shown is a representation 58 of the tip of the surgical instrument 18 in a ninth exemplary pose. The representation 58 may be determined by the processor 2 based on tracking data that describes the ninth exemplary pose of the surgical instrument 18 in the coordinate system by describing the corresponding position and orientation of the surgical instrument 18 in the coordinate system. It can be seen that although the orientation of the surgical instrument 18 is different from Fig.14 and Fig.16 , but the position of the tip of the surgical instrument 18 differs between the two figures. Fig.14 In FIG. 1 , the tip of the surgical instrument 18 is located on the outer surface of the computer model. Fig.16 In FIG. 1 , the tip of the surgical instrument 18 is located below the outer surface of the computer model.

[0097] Fig.16 The current entry point 66 shown is the same as Fig.12 and Fig.14 Therefore, the distance between the current entry point 66 and the planned entry point 48 on the trajectory line 56 of the surgical instrument 18 in the ninth exemplary posture satisfies the predetermined condition, and, when the surgical instrument 18 is in the ninth exemplary posture, the navigation view to be displayed controlled by the processor 2 is a bull's eye view centered on the straight line extending between the current entry point 66 and the planned target point 52. It can be seen that the trajectory line 56 is aligned with the viewing direction 64 and extends between the current entry point 56 and the target point 52.

[0098] Fig.17 An example of a navigation view using the surgical instrument 18 being in a ninth exemplary posture is shown. As can be seen, the indication 58 is centered on the center of the bull's-eye view. In other words, the viewing direction 64 of the bull's-eye view corresponds to the direction of the longitudinal axis 24 of the shaft 22 of the surgical instrument 18, and the tip of the surgical instrument 18 is shown as the indication 58. Because the trajectory line 56 reaches the planned target point 52 in this case, the indication 62 indicates a deviation of 0 mm. In order to guide the surgeon to move the surgical instrument 18 so as to reach the target 50, the indication 60 is shown. The indication 60 shows a value of -12.1 mm in this case as the distance between the tip of the surgical instrument 18 and the target point 52. This is because, unlike Fig.14 and Fig.15 In comparison, Fig.16 and Fig.17 , the tip of surgical instrument 18 is positioned closer to target 50.

[0099] In addition, the navigation view in this example includes: a progress bar 68, which is concentrically formed around the straight line between the current entry point 66 and the target point 52. The progress bar indicates the distance between the tip of the surgical instrument 18 and the planned target 50 (i.e., the planned target point 52). Specifically, the progress bar 68 is an indication of the relationship between the distance between the tip of the surgical instrument 18 and the current entry point 66 and the distance between the current entry point 66 and the target point 52. The closer the end of the surgical instrument 18 is to the target 50, the fuller the progress bar (i.e., the more complete). In another variation, the progress bar can refer to a countdown bar. In this case, the closer the end of the surgical instrument 18 is to the target 50, the emptier the progress bar (i.e., the more incomplete).

[0100] Figures 18 to 22 A second example of a navigation view is shown with the straight line between the current entry point 66 and the target point 52 as the viewing direction. These figures show the progress bar 68 in different states. In the second example of the navigation view, the progress bar 68 is a countdown bar.

[0101] Fig.18 The navigation view with the progress bar 68 is shown with the tip of the surgical instrument 18 positioned over the current entry point 66. In this case, the surgical instrument 18 is in an eighth exemplary posture.

[0102] Fig.19 A navigation view is shown with a progress bar 68 indicating that the insertion of the surgical instrument is 25% complete. Fig.19 The progress bar 68 in FIG. 5 indicates that the distance between the end of the surgical instrument 18 and the current entry point 66 is 25% of the distance between the current entry point 66 and the target point 52. In this case, the surgical instrument 18 is in the same orientation as in the eighth exemplary posture, but in a different position than in the eighth exemplary posture. In other words, the trajectory line 56 of the surgical instrument 18 is 25% of the distance between the current entry point 66 and the target point 52. Fig.18 and Fig.19 Same as in.

[0103] Fig. 20 A navigation view is shown with a progress bar 68 indicating that the insertion of the surgical instrument is 50% complete. Fig. 20 The progress bar 68 in FIG. 5 indicates that the distance between the end of the surgical instrument 18 and the current entry point 66 is 50% of the distance between the current entry point 66 and the target point 52. In this case, the surgical instrument 18 is oriented in the same manner as in the eighth exemplary posture, but is in a position different from the first exemplary posture. Fig.18 or Fig.19 in different locations.

[0104] Fig.21 The navigation view is shown with a progress bar 68 indicating that the insertion of the surgical instrument is 75% complete. Fig. 20The progress bar 68 in FIG. 5 indicates that the distance between the end of the surgical instrument 18 and the current entry point 66 is 50% of the distance between the current entry point 66 and the target point 52. In this case, the surgical instrument 18 is oriented in the same manner as in the eighth exemplary posture, but is in a position different from the first exemplary posture. Figures 18 to 20 in different locations.

[0105] Fig. 22 A navigation view is shown with a progress bar 68 indicating that the insertion of the surgical instrument is 100% complete. Fig. 20 The progress bar 68 in FIG. 5 indicates that the distance between the end of the surgical instrument 18 and the current entry point 66 is 50% of the distance between the current entry point 66 and the target point 52. In this case, the surgical instrument 18 is oriented in the same manner as in the eighth exemplary posture, but is in a position different from the first exemplary posture. Figures 18 to 21 in different locations.

[0106] Fig.23 Different current entry points are shown, which by definition are all located on the trajectory line 56 of the surgical instrument 18. A first point 70 is located on the outer surface of the computer model. A second point 72 is the point closest to the planned entry point 48. A third point 74 is a point located in a plane extending through the planned entry point 48, which plane has as a normal the straight line between the planned entry point 48 and the target point 52. A fourth point 76 is located on the tip of the surgical instrument 18. The current entry point 66 satisfies at least one requirement selected from the following: the current entry point 66 is located on the (i.e., front) tip of the surgical instrument 18; the current entry point 66 is located on the outer surface of the computer model; the current entry point 66 is closest to the planned entry point 48 of any point located on the trajectory line 56; and the current entry point 66 is located in a plane, wherein the plane has a normal defined by the straight line between the planned entry point 48 and the planned target 50 (i.e., the planned target point 52), and wherein the planned entry point 48 is located in the plane. In the present embodiment, the current entry point is the second point 72 , specifically, the point on the trajectory line closest to the planned entry point 48 .

[0107] There is also provided a computer readable medium comprising a computer program comprising instructions which, when executed by a processor, ie the processor 2, causes the processor to perform the method described herein. Furthermore, there is provided a data carrier signal carrying information representing the computer program.

[0108] As described with reference to the exemplary embodiments, the techniques presented herein implement, in some variations, displaying visual cues to decompose the surgeon's task of aligning the surgical instrument 18 into two sequential tasks. In the first task, the leading end of the surgical instrument 18 is aligned with the planned entry point 48. Thereafter, in the second task, the surgical instrument 18 is aligned so that the trajectory line 56 passes through the planned target 50.

[0109] The navigation view is, for example, a bull's eye view viewed along the actual instrument trajectory line 56. The bull's eye view can be combined with the perspective view described above. Figure 1 Together, the perspective views described above are two-dimensional or three-dimensional visualizations of the computer model.

[0110] The fluoroscopic view can be oriented so that it best matches the surgeon's actual perspective angle of the patient 14 located in front of him. The orientation of the fluoroscopic view can be determined based on information from the optical tracking system 6 or the electromagnetic tracking system 26 or from both. The orientation of the fluoroscopic view can also be determined based on at least one known coordinate transformation and / or the surgeon's known position relative to the operating table where the patient 14 is located. This visualization through the fluoroscopic view enables the surgeon to easily find the planned entry point 48 for the patient 14.

[0111] The bull's-eye view showing the representation 58 of the front end of the surgical instrument 18 may also show any point adjacent to the longitudinal axis 24 of the surgical instrument. Fig.10 and Fig.11 As shown in the example in FIG. 5 , the bulls-eye view is initially viewed entirely along the planned trajectory line 54. For example, when the leading end of the surgical instrument 18 is positioned less than an application-specific distance (e.g., 2 mm) from the planned trajectory line, the bulls-eye view changes so that it is currently viewed along a straight line through the current entry point 66 toward the target 50, as shown in FIG. Fig.12 and Fig.13 In this example, the center of the bulls-eye view thus jumps from the planned entry point 48 to the current entry point 66 .

[0112] The surgeon can then use the re-orientation bull's-eye view to align the orientation of the surgical instrument 18 until the trajectory line 56 is as shown. Fig.14 and Fig.15 until it passes through the target 50 as shown, and then Fig.16 and Fig.17 Surgical instrument 18 is shown being moved toward target 50 .

[0113] In most cases, it is more important to reach the target point 52 exactly, but a deviation of a few millimeters from the entry point 48 is usually insignificant. Figure 7 The alignment shown is relative to Figure 5 and Figure 6 The alignment shown is advantageous, wherein trajectory line 56 may slightly miss planned entry point 48, but trajectory line 56 very closely reaches planned target point 52. Thus, the methods described herein support the surgeon in first achieving a "good enough" alignment of surgical instrument 18 with planned entry point 48, and then achieving an accurate alignment of surgical instrument 18 such that trajectory line 56 accurately reaches target point 52.

[0114] This advantageous continuous alignment can be achieved by switching the navigation view from viewing toward the target 50 from the planned entry point 48 to viewing toward the target 50 from the current entry point 66 once the current entry point 66 is “good enough” so that the surgeon can then focus entirely on correcting the alignment of the surgical instrument 18 relative to the patient 14 so that the trajectory 56 reaches the target 50.

[0115] The method of immediately changing the recommended entry point described herein is advantageous relative to simply orienting or aligning the bull's-eye view at the front end of surgical instrument 18 toward a viewing direction looking toward target 50 because it avoids very large directional excursions as the tip approaches target 50. Instead, current entry point 66 may be considered a pivot point about which the surgeon may make corrections to the orientation of surgical instrument 18, and therefore the direction of trajectory line 56.

[0116] A combination of a perspective view and a bull's-eye view may be displayed as a two-dimensional or three-dimensional view facing the surgeon. In addition, once the current entry point 66 is "good enough", the bull's-eye view may be moved from the planned entry point 48 toward the target 50 ( Fig.10 , Fig.11 ) View switches to view from the current entry point 66 towards the target 50 ( Fig.12 and Fig.13 ), so that the surgeon can then focus entirely on correcting the orientation of the surgical instrument 18 by pivoting the surgical instrument 18 on the current entry point 66 so that the trajectory line 56 reaches the target 50.

[0117] By immediately changing the recommended entry point from the planned entry point 48 to the current entry point 66, surgical navigation is improved. For example, the surgeon may not be able to determine or may determine not to accurately position the surgical instrument 18 on the planned entry point 48. In this case, a navigation view that guides the surgeon from the current entry point 66 to the target 50 may be advantageous. By changing the recommended entry point to the current entry point 66 only when the distance between the current entry point 66 and the planned entry point 48 meets a predetermined condition, it can be ensured that the trajectory 56 of the surgical instrument 18 remains sufficiently close to the planned trajectory 54.

[0118] The features described with respect to the exemplary embodiments shown in the accompanying drawings can be easily combined to produce different embodiments. Therefore, it is obvious that the present disclosure can be changed in many ways. These changes are not considered to depart from the scope of the present invention as defined by the appended claims.

Claims

1. A computer-implemented method for controlling the display of a navigation view for surgical navigation, the method comprising: obtaining planning data defining a planning entry point and a planning target, wherein the planning entry point and the planning target are defined in a coordinate system of at least one computer model of the anatomy; obtaining tracking data describing a current pose of the surgical instrument in the coordinate system; Based at least on the tracking data, determining a current entry point located on a trajectory having a fixed spatial relationship to the surgical instrument; and controlling display of a navigation view that visualizes at least one recommended entry point, wherein when a distance between the planned entry point and the current entry point satisfies a predetermined condition, the recommended entry point is immediately changed from the planned entry point to the current entry point, The predetermined condition is that the distance between the planned entry point and the current entry point is less than a threshold value, and The threshold is a value based on the spatial relationship between the planned entry point and the target.

2. The method according to claim 1, wherein: The current entry point meets at least one requirement selected from the following: The current entry point is located on the tip of the surgical instrument; The current entry point is located on an outer surface of the computer model; Among any points on the trajectory line, the current entry point is closest to the planned entry point; as well as The current entry point lies in a plane, wherein the plane has a normal defined by a straight line between the planned entry point and the planned target, and wherein the planned entry point lies in the plane.

3. The method according to claim 1, wherein: The trajectory meets at least one requirement selected from the following: The trajectory line is parallel to the longitudinal axis of the surgical instrument; The trajectory line is parallel to the insertion direction of the surgical instrument; and The trajectory line is orthogonal to the handle of the surgical instrument.

4. The method according to claim 1, wherein: The navigation view visualizes the recommended entry points by aligning or orienting the navigation view relative to the recommended entry points.

5. The method according to claim 1, wherein: The navigation view visualizes the recommended entry points and the planned goals.

6. The method according to claim 5, wherein: The navigation view visualizes the recommended entry points and the planned goals by providing at least one result selected from: displaying the recommended entry point and the goal on a representation of the computer model; as well as The navigation view is oriented relative to at least one of the recommended entry point and the target.

7. The method according to claim 1, wherein: The navigation view has a viewing direction corresponding to a straight line between the recommended entry point and the planned destination.

8. The method according to claim 1, wherein: The navigation view is a bull's-eye view centered on a straight line between the recommended entry point and the planned goal.

9. The method according to claim 1, wherein: The navigation view includes a visualization of a relative spatial relationship between the surgical instrument and at least one destination selected from the recommended entry point and the planning target.

10. The method according to claim 1, wherein: The navigation view includes a visualization of the shortest distance between the trajectory line and the planned target.

11. The method according to claim 1, wherein: The navigation view includes a visualization of a score determined by dividing a first distance by a second distance or dividing the second distance by the first distance, wherein the first distance is the distance between the position of the surgical instrument in the coordinate system and one of the recommended entry point and the target, and The second distance is the distance between the recommended entry point and the target.

12. The method according to claim 11, wherein: The visualization of the score is a progress bar.

13. The method according to claim 12, wherein: The progress bar is formed concentrically around an alignment point in the navigation view.

14. The method according to claim 13, wherein: The alignment point is located on a straight line between the recommended entry point and the planned target.

15. The method according to claim 1, wherein: When the distance between the planned entry point and the current entry point satisfies the predetermined condition, the recommended entry point is permanently changed from the planned entry point to the current entry point.

16. The method according to claim 1, wherein: When the distance between the planned entry point and the current entry point no longer satisfies a predetermined standard, the recommended entry point is immediately reset from the current entry point to the planned entry point.

17. A processor for a surgical navigation system, the processor being configured to: Obtaining planning data that defines planning entry points and planning objectives, where: The planning entry point and the planning target are defined in a coordinate system of at least one computer model of the anatomy; obtaining tracking data describing a current pose of the surgical instrument in the coordinate system; determining, based at least on the tracking data, a current entry point located on a trajectory having a fixed spatial relationship to the surgical instrument; as well as controlling display of a navigation view that visualizes at least one recommended entry point, wherein when a distance between the planned entry point and the current entry point satisfies a predetermined condition, the recommended entry point is immediately changed from the planned entry point to the current entry point, The predetermined condition is that the distance between the planned entry point and the current entry point is less than a threshold value, and The threshold is a value based on the spatial relationship between the planned entry point and the target.

18. A computer readable medium comprising a computer program, the computer program comprising instructions which, when executed by a processor, cause the processor to: Obtaining planning data that defines planning entry points and planning objectives, where: The planning entry point and the planning target are defined in a coordinate system of at least one computer model of the anatomy; obtaining tracking data describing a current pose of the surgical instrument in the coordinate system; determining, based at least on the tracking data, a current entry point located on a trajectory having a fixed spatial relationship to the surgical instrument; as well as controlling display of a navigation view that visualizes at least one recommended entry point, wherein when a distance between the planned entry point and the current entry point satisfies a predetermined condition, the recommended entry point is immediately changed from the planned entry point to the current entry point, The predetermined condition is that the distance between the planned entry point and the current entry point is less than a threshold value, and The threshold is a value based on the spatial relationship between the planned entry point and the target.

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