EP1618511A2

EP1618511A2 - Method for simulating musculoskeletal strains on a patient

Info

Publication number: EP1618511A2
Application number: EP04727826A
Authority: EP
Inventors: Georg N. Duda; Markus O. Heller; William R. Taylor
Original assignee: Heller Markus O
Current assignee: Heller Markus O
Priority date: 2003-04-17
Filing date: 2004-04-16
Publication date: 2006-01-25
Also published as: WO2004095341A3; US20060287612A1; WO2004095341A2

Abstract

The invention relates to a method and a device for simulating musculoskeletal strains on a patient, especially for preparing or monitoring surgical interventions and/or planning and/or monitoring rehabilitation. According to the invention, individual musculoskeletal parameters of the patient are determined first, particularly by automatically measuring anthropometric parameters and/or the position and/or alignment of joints, especially also gait-related data such that individual musculoskeletal strains are automatically determined from the determined musculoskeletal parameters of the patient. The individual musculoskeletal strains thus determined are evaluated in a computer-assisted manner regarding at least one target criterion, particularly the contact forces or the degree of motion of a joint or the fragment movements of a fracture. The aim of the invention is to create a method for evaluating musculoskeletal strains on a patient, by means of which above all surgical interventions or rehabilitative measures can be improved.

Description

Process for the simulation of musculoskeletal

Burden of a patient

description

The invention relates to a method for simulating musculoskeletal stresses on a patient according to the preamble of claim 1.

There is a social trend towards an active lifestyle, which is characterized, among other things, by the practice of high-risk sports paired with increased physical activity, even in old age. In addition, life expectancy is increasing and a general aging of the population can be observed. Both phenomena are accompanied by an increase in musculoskeletal disorders. Their particular relevance is also evident from the Bone & Joint Decade proclaimed by the HO.

In concrete terms, this means that the number of people who, for example, need artificial joints, who suffer a fracture or who are required for rehabilitation measures be borrowed. This development is of enormous economic importance due to the associated costs of operations and rehabilitation measures or the indirect costs of work ability, but also an important socio-cultural component, namely the maintenance of quality of life. Overall, it follows that an optimization of the corresponding measures such as operations and rehabilitation measures is of great importance for the development of society.

However, the success of a treatment, particularly in the context of joint replacement or fracture care, depends very much on the individual musculoskeletal stresses achieved before and after. As part of the measures, an attempt is made to actively change them or to restore a "normal state", which is usually also the optimal state. Knowledge of musculoskeletal stress is currently limited, since these are complex systems The musculoskeletal load is currently not included in the planning or implementation of operations and / or rehabilitation measures, so the outcome of the operation or rehabilitation measures depends to a large extent on the experience of the surgeon or therapist - gig.

The object of the present invention is therefore to specify a method for evaluating musculoskeletal stresses on a patient, with which in particular surgical interventions or rehabilitation measures can be improved. The object is achieved by a method for simulating musculoskeletal loads with the features of claim 1.

Accordingly, individual musculoskeletal parameters of the patient are first determined. In particular, automatic measurement of anthropometric parameters, automatic derivation of anthroprometric parameters from a system for computer-assisted surgery, in particular a surgical navigation system, and / or the position and / or orientation of joints are determined. A surgical navigation system provides the surgeon with a virtual representation of the operating area. This representation is created, for example, using CT images taken before the operation. The surgeon can also observe the movements of instruments in the virtual representation, whereby he can follow a treatment plan previously arranged in the virtual representation. This also enables a comparison of the real OR situation with the planned situation. It is also possible to actively control instruments using the navigation system. The method and the device for carrying out the method can, for example, be installed on a central server. In this case, the users (eg therapists, surgeons, technicians) would not access data locally, but could obtain the necessary information via the Internet or, if necessary, also enter it. This means that the data can be used during the planning and subsequent steps during therapy. A center can also be set up that centrally maintains and distributes data for different users. In the second step, the individual musculoskeletal loads are automatically determined from the determined individual musculoskeletal parameters. In the third step of the method according to the invention, the individual musculoskeletal loads are evaluated with the aid of at least one target criterion. In particular, the contact forces or the amount of movement of a joint or the fragment movements of a fracture can serve as the target criterion.

The method according to the invention can be used to support surgical procedures, such as interventions for total joint replacement, interventions on ligament structures, interventions in the context of conversion osteotomies, and interventions in the context of fracture care for humans and animals.

By determining an assessment of the individual musculoskeletal stresses with regard to at least one target criterion, surgical procedures can be supported in planning, implementation and evaluation. With the aid of the method, the surgeon or therapist can directly assess the effects of a planned intervention non-invasively and can evaluate and adjust his operation or therapy plan accordingly. By using individualized, biomechanical musculoskeletal stress and strain analyzes, the planning, implementation and evaluation of surgical procedures can be objectified even before the intervention.

In a variant of the method, at least one of the musculoskeletal parameters, in particular the position, is determined after the assessment of the individual musculoskeletal loads and / or the orientation of a joint varies. Then the individual musculoskeletal stresses are again determined automatically, taking into account the at least one varied musculoskeletal parameter. A computer-aided assessment for individual musculoskeletal stresses with regard to the at least one target criterion is then carried out again. In this way, a comparison can be made between two possible situations or operating plans. For example, it can be examined how a different position of a joint behaves with regard to the at least one target criterion, for example with regard to the contact forces of the joint that occur. This enables precise operation planning. The varied parameter can be optimized in a further development of the invention by repeating the variation of the at least one parameter until a defined target value of at least one target criterion is reached. This optimizes the target criterion and thus the parameter set iteratively. In this way, for example, the optimal position of an artificial joint can be determined.

The musculoskeletal parameters determined in this way, for example the position of a joint, are advantageously output on an output device and / or stored in a storage device. Additionally or alternatively, the output data can also be transmitted to a computer-assisted surgery system and / or in the surgical navigation system, so that these data can also be available intra-operatively. The individual and varied musculoskeletal parameters obtained in this iterative procedure and corresponding to the target value advantageously serve as the basis for planning an operative intervention. In particular, they serve as the basis for the selection of components, for example different joint types, with regard to the positioning of the components or the decision about the removal of temporary implants.

In order to be able to determine the effects of different implants on the musculoskeletal load on the patient, the individual musculoskeletal parameters can be varied taking into account the data of implants, in particular their dimensions and ranges of movement. For example, different implants can be tested against each other and the optimal implant for the respective patient anatomy can be selected taking into account the respective target criteria.

For the automatic determination of the individual musculoskeletal loads, two different types of methods are provided in further developments of the method according to the invention:

On the one hand, the individual or the varied musculoskeletal parameters are compared with the musculoskeletal reference parameters stored in a database, with musculoskeletal reference loads corresponding to the musculoskeletal reference loads being determined as the individual musculoskeletal loads. The musculoskeletal reference parameters can be present in the database as discrete values. When present Discrete values make sense to compare the reference parameters with the individual musculoskeletal parameters using functional relationships, in particular using interpolation.

On the other hand, in a further development of the method according to the invention, the individual musculoskeletal loads are calculated from the determined individual musculoskeletal parameters. The calculation is advantageously based on a biomechanical and / or a mathematical model. In a development of the method according to the invention, the biomechanical or mathematical model used in each case is already adapted to the individual musculoskeletal parameters. For this purpose, a biomechanical and / or a mathematical model can be selected from at least one database on the basis of the determined individual musculoskeletal parameters.

The selected model is then optimized and adapted to the individual musculoskeletal parameters determined. It is therefore advantageous to calculate the individual musculoskeletal loads with the aid of a musculoskeletal model, taking into account the individual patient anatomy or taking into account the individual anthropometric data of the patient.

To simplify the computer-aided evaluation of the respective process results, these individual musculoskeletal loads are advantageously visualized. The respective treating doctor or therapist can use the visualization to quickly and easily check and change their treatment plan. The indi- vidual musculoskeletal stresses are represented graphically and / or numerically using an anatomical model.

By evaluating the individual musculoskeletal loads, a rehabilitation process can also be assessed and / or controlled, for example, by recognizing. For example, corresponding data can be accessed via the Internet.

In an advantageous development of the method, the individual musculoskeletal parameters of the patient are determined by measurements. To simplify and objectify the method, at least one of the individual musculoskeletal parameters can be measured automatically. Such a measurement can take place in particular by means of image recognition, computer tomography and / or by means of motion sensors.

Furthermore, it is advantageous if individual movement parameters, in particular gait parameters, are determined and these are used for the automatic determination of individual musculoskeletal loads. For example, individual gait parameters can be obtained by taking pictures of legs in motion. Three-dimensional positions of the body parts can then be determined from the images. The ground reaction force that acts on the foot from the ground is also measured. It is particularly advantageous if the individual gait parameters are determined from personal data stored in a database and / or are recorded individually for one person.

The object is also achieved by a device having the features of claim 22. Such a device can be implemented as a software and / or hardware-based variant in a data processing system. This data processing system then has a link to a database with which musculoskeletal loads and / or individual movement parameters can be stored.

The method is further explained below using the drawings of the figures. Show it:

Figure 1 is a schematic representation of the method according to the invention in a first embodiment.

2 shows the method in a second, more detailed embodiment;

3 section from the method shown in FIG. 2 with regard to the induction of individual musculoskeletal loads from a database,

4 shows a detailed section from the method of FIG. 2, the calculation of musculoskeletal loads being shown;

5 further section from the method of FIG. 2, which relates to the visualization; and

6 shows a possible visualization of musculoskeletal stress.

FIG. 1 schematically shows the method according to the invention. In the first step, the individual musculoskeletal parameters of the respective patient are determined. This includes in particular anthropometric data, such as for example the bone dimensions and their masses, the center of gravity of the bones and other inertia parameters, the pelvic dimensions, the respective thighs and lower legs - or the length of the feet. Other anthropometric data related to the automatic determination of the individual musculoskeletal loads can also be included here.

The determination of the individual musculoskeletal parameters in step 1 can be determined by automatic measurements, for example taken from computer tomography, by external measurements of the patient, by movement analyzes or by other measurement methods. Additionally or alternatively, anthropometric parameters can be automatically adopted by a navigation system.

In step 40 e.g. include individual movement parameters in the process. In the case of the lower extremities, a gait analysis can be used. Here, e.g. The movements of the individual leg segments during certain activities (e.g. running, climbing stairs, getting up from a chair, squats etc.) are recorded with an optical measuring system. To ensure that the optical detection can be carried out, reflective markers are arranged on a patient and can be detected by the measuring system. The spatial and temporal position of the body segments (e.g. pelvis, thigh, knee, lower leg, foot) can then be determined. In conjunction with several cameras, a three-dimensional movement image of the body segments can be obtained from the two-dimensional images. Also at the

Gait analysis measured the reaction force of the floor to the feet. The movement parameters can be calculated from database values of a patient (e.g. height, weight) and / or on the patient. Even if gait parameters are used in the following, movement parameters of other parts of the body can in principle also be used.

In step 2, the individual musculoskeletal loads are automatically determined from the determined individual musculoskeletal parameters and, if applicable, from the individual movement parameters. This determination can be made, for example, by comparing the determined musculoskeletal parameters with reference parameters stored in a database, or by calculating the respective individual musculoskeletal loads. These methods will be discussed further in the description of the following figures.

In step 3 of the method shown in FIG. 1, the automatically determined, individual musculoskeletal strains are now evaluated with the aid of a computer with the aid of a target criterion. The target criteria can be, for example, the contact forces or the extent of movement of a joint or the necessary fragment movements of a fracture. A combination of several target criteria can also be considered and evaluated.

In a simple implementation of the method, the evaluation or the individual burdens are then output or documented in step 6.

To optimize a parameter set, a further development of the method can be used to check in step 4 whether the target criterion has reached a previously defined target value. If this is not the case, step 5 at least one of the individual parameters varies. This is followed by the automatic determination of the individual burdens in step 2 and the assessment of these individual burdens with regard to a target criterion in step 3. If the target value in step 4 is still not reached, a new variation of at least one parameter takes place in step 5. If the target value is reached, the output or documentation takes place in step 6. It is also possible that the data output is automatically on a surgical navigation system takes place.

This iterative procedure enables a parameter set to be optimized with regard to one or more target criteria. The individual parameter set, which is optimized with regard to the individual musculoskeletal loads or with regard to the target criterion, can then be used for planning, for example, an operative intervention or for planning therapeutic measures.

The variation of the at least one parameter in step 5 of the figure can also take into account the dimensions or other parameters of implants. By varying the parameters in step 5, different implants can be tested against each other.

The data obtained and processed are saved and can be used for rehabilitation. Here, e.g. the responsible doctor can access the data via the internet in order to have a specially adapted rehabilitation plan, e.g. to design for physiotherapy.

The method according to the invention is shown in an expanded embodiment in FIG. First, in Step 1 determines the individual musculoskeletal parameters of the respective patient, for example by automatic measurement. The automatic determination of the individual musculoskeletal loads from the determined individual musculoskeletal parameters can then take place either in step 20 via a database query or in step 21 via a calculation of the individual musculoskeletal loads. The individual gait parameters are also included (step 40).

From step 20 or step 21, step 22 then results in the individual musculoskeletal stress of the respective patient. The individual musculoskeletal stress is now prepared for the visualization in step 30. How this happens in detail is discussed in the description of the other figures.

In step 31, the respective individual musculoskeletal stresses are visualized. From the visualization, the musculoskeletal loads are now evaluated with the aid of a computer to determine whether at least one target criterion has reached a specified target value. If this is the case in step 4, the corresponding parameters and the musculoskeletal stresses are output or documented in step 6. If the target value is not reached in step 4, at least one parameter is changed or varied using the visualization in step 50.

With the new parameter set generated in step 50, an automatic determination of the individual musculoskeletal loads in step 20 or in the

Step 21 performed. This iterative process is long demonstrated until the target value of at least one target criterion is reached in step 4.

FIGS. 3 and 4 now show the automatic determination of the individual musculoskeletal loads in the two variants mentioned.

In FIG. 3, the individual musculoskeletal parameters determined in step 2 are compared with reference parameters stored in a stress database 200. The reference parameters of the load database 200 can be present either as discrete values or as continuous values.

If discrete values are available, the comparison between the determined individual musculoskeletal parameters and the reference parameters of the stress database is carried out using functional relationships, in particular using an interpolation. The reference loads corresponding to the reference parameters closest to the determined parameters are then output as the individual musculoskeletal load in step 22.

In this variant, a larger amount of empirical data is to be collected before the method according to the invention is carried out, on the basis of which the load database 200 can be constructed.

FIG. 4 shows the second variant of the automatic determination of the musculoskeletal loads. From the determined individual musculoskeletal parameters in

Step 1 is a suitable anatomical from a database 210 select mechanical and / or biomechanical model or a suitable movement model.

The selected model is adapted in step 211 to the determined individual musculoskeletal parameters 1. In step 212, an individual biomechanical model is obtained which is individually adapted to the respective patient. Individual gait parameters 40 are also included.

With the individual biomechanical model, the individual musculoskeletal loads are now calculated in step 213. These individual musculoskeletal stresses are then assigned to the individual musculoskeletal stress in step 22.

FIG. 5 shows the individual process steps for the visualization of the individual musculoskeletal loads. The individual musculoskeletal stresses of step 22 are prepared together with the data of a database 310 of an anatomical model in step 311. For example, the individual musculoskeletal loads can be assigned to individual anatomical parts. Data can also be processed in a surgical navigation system. The data linked and processed in this way are visualized in step 312.

Such a visualization is shown, for example, in FIG. 6. Individual parameters 1 to m can be varied using the visualization, for example using a graphic representation, on a computer screen using a slide 500. The value of the respective parameter is in a separate display 501 is displayed. This can be an angle or a distance, for example. The musculoskeletal load is visualized using a curve 502, which shows the loads, for example, during a walking cycle or while climbing stairs.

The attending doctor or therapist can now set different values of the respective parameter by moving the slider 500 and in doing so observe how the exposure data change.

Using this visualization and the simultaneous change of parameters, it is possible to find optimal solutions or plan an intervention quickly and efficiently. The attending doctor or therapist can thus see at a glance what the consequences of changing a parameter with regard to a target criterion are.

The description of the figures relates to a special joint, namely a hip joint. However, the teaching according to the invention can in principle be used for all joints, in particular also knee joints, shoulder joints, ankle joints, temporomandibular joints, elbow joints and / or spinal joints.

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Claims

Expectations

1. A method for simulating musculoskeletal stress on a patient, in particular for preparing or monitoring surgical interventions and / or for planning or monitoring rehabilitation, with the steps:

a. Determination of individual musculoskeletal parameters of the patient, in particular by automatic measurement of anthropometric parameters, automatic derivation of anthroprometric parameters from a system for computer-assisted surgery, in particular a surgical navigation system, and / or the position and / or orientation of joints;

b. Automatic determination of the individual musculoskeletal loads from the determined musculoskeletal parameters of the patient;

c. Computer-aided evaluation of the individual musculoskeletal loads with regard to at least one target criterion, in particular with regard to the contact forces or the extent of movement of a joint or with regard to the fragment movements of a fracture.

2. The method according to claim 1 with the additional steps:

d. Variation of at least one musculoskeletal parameter, in particular the position and / or the orientation of a joint;

e. Another automatic determination of the individual musculoskeletal loads taking into account determination of the at least one varied musculoskeletal parameter;

f. Computer-aided evaluation of the individual musculoskeletal loads with regard to the at least one target criterion.

3. The method according to claim 2, characterized in that the steps d. to f. can be repeated until a defined target value of at least one target criterion is reached.

4. The method according to claim 3, characterized in that the musculoskeletal parameters corresponding to the target value are output on an output device, stored in a storage device and / or transmitted to a computer-assisted surgery system and / or to a surgical navigation system.

5. The method according to claim 3 or 4, characterized in that the individual and varied musculoskeletal parameters corresponding to the target value as the basis for the planning of an operative intervention, in particular as the basis for the selection of components, the positioning of components or the decision about the removal of temporary implants.

6. The method according to any one of claims 2 to 5, characterized in that the variation of the individual musculoskeletal parameters in step d. taking into account specifiable data of implants, in particular their dimensions and ranges of movement.

7. The method according to any one of the preceding claims, characterized in that for the automatic determination of the individual musculoskeletal loads, the individual or the varied musculoskeletal parameters are compared with musculoskeletal reference parameters stored in a database, with the muscular -skeletal reference parameters corresponding musculoskeletal reference loads are determined as the individual musculoskeletal loads.

8. The method according to claim 7, characterized in that the musculoskeletal reference parameters are present as discrete values in the database.

9. The method according to claim 8, characterized in that the musculoskeletal reference parameters are compared with the individual musculoskeletal parameters by means of functional relationships, in particular by means of interpolation.

10. The method according to any one of the preceding claims, characterized in that the individual musculoskeletal loads are calculated from the determined individual musculoskeletal parameters.

11. The method according to claim 10, characterized in that the calculation of the individual musculoskeletal loads is based on a biomechanical and / or a mathematical model.

12. The method according to claim 11, characterized in that the biomechanical and / or mathematical model is adapted to the individual musculoskeletal parameters.

13. The method according to claim 11 or 12, characterized in that the biomechanical and / or mathematical model is selected from at least one database on the basis of the determined individual musculoskeletal parameters.

14. The method according to any one of claims 11 to 13, characterized in that the individual musculoskeletal loads are calculated using a musculoskeletal model taking into account the individual patient anatomy.

15. The method according to any one of the preceding claims, characterized in that the individual musculoskeletal loads are visualized for evaluation.

16. The method according to any one of the preceding claims, characterized in that the individual musculoskeletal loads are represented on the basis of an anatomical model, in particular graphically and / or numerically.

17. The method according to any one of the preceding claims, characterized in that a rehabilitation process is evaluated and / or controlled by evaluating the individual musculoskeletal stresses, in particular by means of access via the Internet.

18. The method according to any one of the preceding claims, characterized in that the individual musculoskeletal parameters of the patient are determined by measurements.

19. The method according to claim 18, characterized in that at least one of the individual musculoskeletal parameters is measured automatically, in particular by means of image recognition, computer tomography and / or motion sensors.

20. The method according to any one of the preceding claims, characterized in that individual movement parameters, in particular gait parameters, are determined and these are used for the automatic determination of individual musculoskeletal loads.

21. The method according to claim 20, characterized in that the individual gait parameters are determined from personal data stored in a database and / or are recorded individually for a person.

22. The method according to any one of the preceding claims, characterized in that the position and / or orientation of joints are used for a navigation system for computer-assisted surgery and / or the data are used by a navigation system for computer-assisted surgery.

23. Device for evaluating musculoskeletal loads on a patient with means for carrying out the method according to one of the preceding claims.

24. Movement analysis system, in particular gait analysis system, characterized in that it is coupled to a device according to claim 23.

5. Navigation system for computer-assisted surgery for performing a method according to claims 1 to 22

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