Methods for planning a positioning process and for navigation system-supported positioning of an object in an environment

Abstract

Method for planning a positioning process of an object in an environment, comprising: Providing a digital model of the environment as a modeled environment, which has at least one environment object that is represented in the modeled environment as a modeled environment object; Providing a digital model of the object as a modeled object; Positioning the modeled object in a planned target position within the modeled environment; Providing a first trajectory and a second trajectory that pass through both the modeled environment object and the modeled object and are not parallel; Storing information regarding the course of the first and second trajectories through the modeled environment object; Storing information regarding the course of the first and second trajectories through the modeled object.

Description

[0001] The present invention relates to a method for planning a positioning process and a method for positioning an object in an environment using a navigation system. The methods can be used, in particular, within the context of a navigation system-supported surgical procedure.

[0002] The use of innovative implantation techniques in modern medicine makes it possible to adapt prostheses to the individual needs of the patient, rather than using prefabricated ones. Instead of a standard model, a custom-made prosthesis can be precisely tailored to the patient's size, position, and orientation. However, the full benefit of a prosthesis individually adapted to the patient's needs is only realized if it is implanted correctly—that is, according to the preoperative planning carried out using a 3D computer model of the patient.

[0003] The placement of custom-made prostheses in orthopedics is challenging and prone to error. Despite highly precise preoperative planning (virtually using a 3D model), the complex anatomy and the sometimes limited orientation options due to the absence of anatomical landmarks (prominent points) make achieving this theoretically possible precision in the operating room difficult. Poor prosthesis placement results in premature wear of the components and a shorter lifespan, ultimately leading to earlier follow-up surgery for the patient. Furthermore, it can cause functional impairment, restricted mobility, and pain. Intraoperative 3D navigation systems exist for standard implants, which can help improve prosthesis alignment. However, with custom-made prostheses, the unique shape created specifically for the patient makes it impossible to scan the product into the system.Therefore, custom-made prostheses are currently placed "freehand" by the surgeon. This has the obvious disadvantage that the results of the surgeries depend on the surgeon's level of training and experience. While some custom-made templates exist to facilitate placement, these are difficult to use in the operating room because interposed soft tissue often prevents proper alignment. The state of the art is represented by DE 10 2006 048 451 A1 and US 2022 / 0 087 746 A1.

[0004] Based on the problem described above, many other areas of industry generally require the precise placement of an object within its environment. For example, analogous to positioning a prosthesis during surgery, a technical component often needs to be attached to another in a predetermined, intended orientation.

[0005] Using the present invention, a 3D object can be positioned relatively easily and precisely relative to a second 3D object in space, and in particular against it, using any commercially available navigation system. The type of navigation system used is irrelevant.

[0006] According to one application, this allows an implant to be positioned precisely at its intended location and fixed in its correct orientation. The correct positioning of, for example, a hip socket significantly increases the implant's lifespan and can prevent or delay the need for subsequent surgeries.

[0007] With regard to its application in the medical field, the present invention is characterized by a connection between a virtual and a therapeutic object via several non-parallel trajectories. These are integrated prior to surgery into both the imaging dataset, e.g., a CT scan of the patient, and the individual prosthesis to be manufactured (e.g., using an additive manufacturing process such as 3D printing). This enables rapid intraoperative navigation and placement of prostheses. As a result, a reduction in operating time can generally be expected, and the overall time required for the surgery can be significantly reduced.

[0008] According to the invention, a method for planning a positioning process of an object in an environment is provided. The method is a computer-implemented method in which the planning is carried out in a computer program based on 3D models of the environment and the object.

[0009] The first step of the process involves providing a digital model of the environment, which contains at least one environment object. Simultaneously, a digital model of the object is provided. A standard 3D modeling program (e.g., CAD software) can be used for this purpose, in which the environment, particularly the environment object, and the object itself are represented as freely movable and rotatable models. The at least one environment object is an object within the environment, such as a higher-level object or component, to which the environment object is to be connected.

[0010] In a further step, the process involves positioning the object in a planned target position within its environment. The positioning process is characterized by the fact that the object is placed at its target position and aligned within that position.

[0011] In a further step, the process involves providing a first trajectory and a second trajectory, which pass through both the surrounding object and the object itself, and are not parallel. The trajectories can be understood as rays that are "shot" through the object and the surrounding object in the corresponding 3D program. Each trajectory therefore has an entry point and an exit point at each of the objects, which completely define its path through each of them.

[0012] In a further step, the process involves saving information regarding the course of the first and second trajectories through the modeled environment object. Saving here primarily refers to recording the paths of the trajectories through the modeled environment project. For this purpose, the trajectory paths through the modeled environment object can be integrated into the data set describing it. For example, the trajectories can be linked to the environment body as spatially stable STL files and output as a modified data set.

[0013] In a further step, the procedure, analogous to the previous step, involves storing information regarding the course of the first and second trajectories through the modeled object.

[0014] Because the at least two trajectories passing through the modeled environment object and the modeled object are not parallel, the entry and exit points of the trajectories through the two modeled objects (the modeled environment object and the modeled object) uniquely define their position and orientation relative to each other. The trajectories can therefore be understood as alignment rays, which serve as tools both in the planning phase and subsequently in the actual positioning phase to leave an imprint on the two modeled objects in the form of the entry and exit points of the trajectories. The entry and exit points of the trajectories can be understood as a kind of code that specifies the relative position of the two objects.

[0015] According to further embodiments of the method, storing information regarding the path of the first and second trajectories through the object can include storing the intersection points between the object's surface and the first and second trajectories. Typically, two intersection points with the object can be expected per trajectory, each corresponding to an entry or exit point. Two intersection points per trajectory are sufficient to uniquely define its path through the object and thus its position in 3D space.

[0016] According to further embodiments of the method, this can further include adapting the digital model of the object by creating a mechanical interface on the object at each of the intersection points of the first and second trajectories with the object. In this step, the originally used digital model, e.g., the corresponding CAD model of the object, can be modified by creating component-like mechanical interfaces in the object model, the locations of which are defined by the intersection points. Preferably, the interfaces located further away from the surrounding object can serve as the locations of the mechanical interfaces.

[0017] According to further embodiments of the method, the mechanical interfaces can each have a longitudinal axis that extends essentially along the trajectory passing through the corresponding entry point. In other words, the component-based mechanical interfaces can be designed such that their longitudinal extent, i.e., roughly speaking, their extension away from the surface of the object, runs essentially along the trajectory belonging to that interface. The purpose of such a design of the mechanical interfaces is to align an auxiliary device coupled to them, e.g., a navigation pointer, along the trajectory belonging to that interface. In the structural design of the interface, it is important that the navigation pointer can be coupled to it (temporarily) in an axially stable manner, i.e., so that after insertion or removal, the navigation pointer remains in its original position.When attaching the navigation pointer, ensure that it cannot be tilted in the mechanical interface.

[0018] According to further embodiments of the method, the mechanical interface can have a recess or an outwardly projecting receptacle. The outwardly projecting receptacle can, for example, be an insertion sleeve into which the tip of a navigation pointer can be inserted. The specific design of the mechanical interface can ultimately be adapted to the shape, particularly the tip, of the navigation pointer used in conjunction with the navigation system. Additionally, an adapter can be inserted into the recess or the outwardly projecting receptacle to (temporarily) connect a navigation pointer. This can be particularly useful if the mechanical interface is to be used for other purposes during the operation, such as connecting several implant components.

[0019] In this context, it should be noted that, within the scope of this description, the term "navigation system" refers to a system used in the medical field that operates based on preoperative CT or MRI scans and can display the position and orientation of a corresponding navigation spinner, as well as other objects equipped with corresponding tracking antennas, on a screen during surgery. This facilitates orientation within the patient during an operation. However, such a system can be used analogously in other areas of technology to precisely and quickly position and secure objects relative to one another.

[0020] According to further embodiments of the method, positioning the object can involve bringing the object into contact with the surrounding object. This ensures that at least one intersection point of the object and at least one intersection point of the surrounding object correspond to each other and, when the object is subsequently positioned in real-world situations, correspond to contact points between the two objects. In preferred embodiments, the object and the surrounding object each have two interfaces that correspond to each other. This uniquely defines the position and orientation of the two objects relative to each other.

[0021] According to further embodiments of the method, the object can be a prosthesis (implant), preferably a bone prosthesis, and the surrounding object can accordingly have a surrounding bone structure. In this embodiment, the method according to the invention thus serves to prepare the surgery in the computer model in such a way that, during the subsequent surgery, the prosthesis can be placed in its correct position in the patient with the aid of a navigation system.

[0022] According to further embodiments of the method, it can also include manufacturing the object according to the adapted digital model of the object. Manufacturing can be carried out using an additive process, e.g., a 3D printing process or a sintering process. During the manufacturing of the implant, it is prepared for the subsequent method of navigation system-supported positioning of an object in an environment by forming the aforementioned recesses or outwardly projecting protrusions at at least two intersection points on the object. This allows the implant to be prepared for the (temporary) attachment of a navigation pointer.

[0023] The invention further provides a method for positioning an object in an environment using a navigation system. This method can be used in any industrial environment where there is a need, for example, to attach complex objects to others in a predetermined position.

[0024] In a first step, the method involves placing an object produced using the previously described method in the environment, which contains at least one environment object. The position of the environment object and the course of the first and second trajectories through it are referenced in a local navigation system. For this purpose, at least one antenna and / or at least one transmitter can be arranged on the environment object, enabling a corresponding transmitter or sensor to detect the position of the environment object in space. The computer-aided navigation system can display a model image of the environment object on a screen and simultaneously show the course of the trajectories through the model image. The position of the environment object in space relative to the transmitter or sensor (there can be several) is known in the navigation system.

[0025] In a further step, the method involves connecting a navigation pointer to the object at the first mechanical interface provided therein. The navigation pointer is referenced in the local navigation system and configured to provide a virtual extension along its longitudinal axis, which is visible in the navigation system. In particular, the navigation pointer can be connected to the object in an axis-stable manner. The navigation system knows the position of the navigation pointer, so that its position and orientation in real space can be displayed on a corresponding screen, in addition to displaying the model of the surrounding object. The orientation of the navigation pointer is indicated by the virtual extension in the real world, which is visible on the screen connected to the navigation system.

[0026] In a further step, the object is positioned within its environment such that the virtual extension of the navigation pointer in the navigation system overlaps with the corresponding trajectory from the first and second trajectories through the environment object. In this step, corresponding interfaces, one at each object, are merged. By overlapping the corresponding trajectory with the virtual extension of the navigation pointer, the object is prepared for a position and orientation that corresponds to the position and orientation from the preceding planning phase. However, in this phase, the object can still rotate around the trajectory or the virtual extension. This remaining degree of freedom is subsequently eliminated by means of the second trajectory.

[0027] In a further step, the process involves fixing the object to the surrounding object at the first interface. Here, the object can be fixed in such a way that it cannot be moved along the trajectory, but can rotate around it. For example, the object can be attached to the surrounding object using a wire.

[0028] In a further step, the procedure involves fixing and connecting a navigation pointer to the object at the second mechanical interface provided within it. This step is analogous to coupling the navigation pointer to the first mechanical interface. The navigation pointer can be the same one used previously, which is then first detached from the first mechanical interface. Optionally, a second navigation pointer can be used.

[0029] In a further step, the procedure aligns the object in such a way that the virtual extension of the navigation pointer in the navigation system overlaps with the associated trajectory running from the first and second through the environment object.

[0030] Finally, the procedure involves fixing the object in its target position relative to the surrounding object. Since, prior to final fixing, the object was positioned and oriented such that the virtual extensions of the navigation pointer in the navigation system's display overlapped with the corresponding trajectories from the previously executed planning phase, it can be assumed that the object has been connected to the surrounding object in its intended position. Because the at least two trajectories are not parallel, it can be ensured that there are no degrees of freedom in the object positioning procedure, and consequently, the object's position corresponds to its position from the planning phase.

[0031] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0032] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings. Fig. Figure 1 illustrates an embodiment of the method for planning a positioning process of an object in an environment. Fig. Figure 2 illustrates an embodiment of the method for navigation system-supported positioning of an object in an environment.

[0033] In Fig. Figure 1 illustrates an exemplary scenario that can serve as the basis for planning the positioning process of an object within an environment. The scene depicted is represented in a computer program. Within this program, the object O can be positioned within an environment U, which contains at least one environment object UO. Both the object O and the environment object UO can exist as 3D models. The model representing the object O may have been created using a design program and may correspond to the data set used to manufacture the object O, for example, an implant or a component within a traction battery of an electric vehicle. The 3D planning of the object O's position within the environment U, and in particular relative to the environment object UO, can be performed using CAD / CAM software.

[0034] Once object O has been moved into its final or desired position within the environment U, which in this case means that it is in a desired position adjacent to the environment object UO, trajectories T1-T3 are generated that pass through both the environment object UO and object O. At least two of these trajectories are not parallel to each other. In the example shown, this is the case for the first trajectory T1 and the third trajectory T3. Without loss of generality, it can be assumed that the trajectories T1-T3 are generated such that they first pass through object O and then through the environment object. Consequently, three entry points E11-E13 and three exit points A11-A13 are provided on the surface of object O. Similarly, three entry points E21-E23 and three exit points A21-A23 are also provided on the surface of the environment object UO.The course of a trajectory within each of the two objects O, UO is uniquely defined by an entry and exit point. If more than two trajectories exist, each additional one can be included for redundancy and used for plausibility checks during the actual positioning procedure.

[0035] Information regarding the course of trajectories T1-T3 through the environment object UO and their course through object O is stored, for example, as lines passing through the bodies or in the form of pairs of entry and exit points Exy, Axy, where x={1,2} and y={1,2,3}. For the subsequent navigation system-supported positioning of the real object O in the corresponding environment U, the courses of trajectories T1-T3 through the environment object UO are particularly relevant. Here, the trajectories T1-T3 can, for example, be linked to the environment body UO as position-stable STL files and output as a data set.

[0036] In a further step, the 3D model of object O can be modified so that either sleeves H1, H2, as is the case for the first and second trajectories T1, T2, or a recess V, as is the case for the third trajectory T3, are modeled on object O at the entry points E11-E13. These can be dimensioned to form a fixed, axis-stable connection with a navigation pointer in a subsequent process. Object O can then be manufactured directly from the modified 3D dataset, for example, using 3D printing, including the sleeves H1, H2 and the recess. Optionally, hollow channels can be included within object O, corresponding to the paths of trajectories T1-T3.

[0037] In Fig. Figure 2 illustrates an exemplary scenario that serves as the basis for the procedure for navigation system-assisted positioning of an object O in an environment U. This procedure is carried out in a real environment RU, with the process additionally supported by a navigation system. Both a navigation pointer N and the environment object UO are referenced in the navigation system. This means that the position and orientation of these objects are known to the navigation system and can be displayed during the positioning process. Models of both objects O and UO are also stored in the navigation program. The spatial detection of the two objects can be achieved using localization antennas L, which are attached to known locations on both objects. The object O to be positioned, however, does not need to be known to the navigation system.Additionally, the display shows the course of the trajectories T1 and T3 (optionally also T2) through the surrounding object.

[0038] After that, using the previously based on Fig. Once the object O, manufactured according to the procedure described in section 1, has been placed in the (real) environment RU, which contains at least one environment object UO, the navigation pointer N of a navigation system is connected to the object O at the first mechanical interface provided therein. As already mentioned, the navigation pointer N is referenced in the local navigation system and is configured to provide a virtual extension V1 as a navigation line along its longitudinal axis, which is visible in the navigation system. The virtual extension V1 is visible on the display of the navigation system, but not in the real environment RU. If necessary, however, the virtual extension V1 can also be displayed in the real environment RU using a laser pointer.

[0039] After an axially stable, temporary connection has been established between navigation pointer N and object O, for example by inserting a tip of the navigation pointer N into the first sleeve H1, object O is positioned within the environment RU at the surrounding object UO. This occurs such that the virtual extension V1 of the navigation pointer in the navigation system overlaps with the corresponding first trajectory T1. This first state Z1 is in Fig. Figure 2 is shown. Once the overlap is established, this represents the temporary end position of the navigation pointer N and thus of the object O. In this temporary end position, the object O can be fixed to the first interface on the surrounding object UO. After this has been done, the navigation pointer N can be separated from the first mechanical interface, i.e., the first sleeve H1 at the first entry point E11, thereby ending the first state Z1.

[0040] The process is then carried out with respect to the second selected mechanical interface, in this case the recess V. The navigation pointer N can be inserted into this with or without a previously attached adapter, which places the navigation pointer N in a second state Z2. Now, the object O can be aligned so that, on the navigation system's display, the virtual extension V2 of the navigation pointer N, which belongs to the second state Z2, overlaps with the corresponding third trajectory T3. Once this has been done, the object O can be fixed in this final position on the surrounding object UO.

[0041] The overlap of the virtual extensions V1 and V2 of the navigation pointer N with the trajectory T1-T3 associated with the corresponding mechanical interface ensures that object O is fixed to the surrounding object UO in the planned position during the positioning process. The correct 3D position of object O can be further refined using additional trajectories. Fig. 2. This can be verified via the additional second trajectory T2. For this purpose, the navigation pointer N can be coupled to the object O at the second entry point E12 using the second sleeve H2.

Claims

[1] Method for planning a positioning process of an object in an environment, comprising: Providing a digital model of the environment as a modeled environment, which has at least one environment object that is represented in the modeled environment as a modeled environment object; Providing a digital model of the object as a modeled object; Positioning the modeled object in a planned target position within the modeled environment; Providing a first trajectory and a second trajectory that pass through both the modeled environment object and the modeled object and are not parallel; Storing information regarding the course of the first and second trajectories through the modeled environment object; Storing information regarding the course of the first and second trajectories through the modeled object. [2] Method according to claim 1, wherein the storage of information regarding the course of the first and second trajectories through the modeled object comprises storing the intersection points between the surface of the modeled object and the first and second trajectories. [3] Method according to claim 2, further comprising: Adapting the modeled object by forming a mechanical interface on the modeled object at each of the intersection points of the first trajectory and the second trajectory with the modeled object. [4] Method according to claim 3, wherein the mechanical interfaces each have a longitudinal axis which extends substantially along the trajectory passing through the associated entry point. [5] Method according to claim 3 or 4, wherein the mechanical interface has a recess or an outwardly projecting receptacle. [6] Method according to any one of claims 1 to 5, wherein the positioning of the modeled object comprises bringing the modeled object into contact with the modeled environment object. [7] Method according to any one of claims 1 to 6, wherein the modeled object is a prosthesis, preferably a bone prosthesis, and the modeled surrounding object has a surrounding bone structure. [8] Method according to any one of claims 3 to 7, insofar as it refers back to claim 3, further comprising: Manufacturing the object according to the adapted modeled object. [9] Method for navigation system-assisted positioning of an object in an environment, comprising: Providing an object produced by the method according to claim 8 in the environment which has at least one environment object, wherein the position of the environment object and the course of the first and second trajectories through it are referenced in a local navigation system; Connecting a navigation pointer to the object at the first mechanical interface provided therein, wherein the navigation pointer is referenced in the local navigation system and is configured to provide a virtual extension along its longitudinal axis that is visible in the navigation system; Positioning the object within the environment at the environment object such that the virtual extension of the navigation pointer in the navigation system overlaps with the corresponding trajectory from the first and second through the environment object; Fixing the object to the surrounding object at the first interface; Connecting a navigation pointer to the object at the second mechanical interface provided therein. Aligning the object so that the virtual extension of the navigation pointer in the navigation system overlaps with the corresponding trajectory running from the first and second through the environment object; Fixing the object in its target position on the surrounding object.

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