Device for mechanical testing of functional segments of human body

Technical field

The invention relates to a device for mechanical testing of functional segments of human body, while the device comprises fastening elements of the tested functional segment of human body and a driving device.

Background art

There is known a device for mechanical testing of functional segments of human body, e.g. according to DE 100 63 630 A1 and DE 199 12 473 A1 , whose common disadvantage is that they enable only acting on the ends of the tested functional segments of human body, and so they do not enable a targeted mechanical acting on each section of the tested functional segments of human body, e.g. during testing of spinal systems with several vertebras, etc. The goal of the invention is to eliminate or at least to minimise the disadvantages of the background art.

Principle of the invention

The goal of the invention has been reached by the device for mechanical testing of functional segments of human body, whose principle consists in that the fastening elements of the tested functional segment of human body are positioned on at least two fixation plates, that are on their outer perimeter connected by means of a system of angle-wise arranged linear drives, while the linear drives are coupled with a control device and the testing space for the tested functional segment of human body is situated in the inner space delimited by the fixation plates and linear drives.

According to an advantageous embodiment the fixation plates are provided with a centre through hole.

According to another embodiment the fixation plates are of a circular shape, while they are in their centre section provided with the circular through

hole with fastening elements for the tested functional segment of human body and on their outer perimeter they are equipped with connecting elements for removable attachment of ends of the linear drives.

The advantage of this solution is that its embodiment enables a targeted acting on each part of tested multiple-part functional segment of human body, namely by usage of always optimal number of fixation plates according to the number of parts of the tested functional segment of human body. By application of so called Stewart's structure is in principle enabled any mutual motion of each two neighbouring fixation plates, by which it is possible to simulate very precisely even very complicated overall motions of tested multiple-part functional segments of human body, at which the individual parts, e.g. spine vertebrae, move exactly one towards another. This enables e.g. to examine in a greater detail the impacts of respective medical interventions to resultant mobility of the tested functional segment of human body, and this enables improvements in designing of fixators and substitutions for patients undergoing such surgical treatments.

Description of the drawing

The invention is schematically represented on the drawing where Fig. 1 shows the block scheme of arrangement of the device according to the invention, Fig. 2 arrangement of the device according to the invention for testing of simple elements, Fig. 3 arrangement of the device according to the invention for testing of multiple-part functional segments, e.g. parts of the spine, Fig. 4 arrangement of the device according to the invention for testing a section of the spine with applied fixator, Fig. 5 arrangement of the device according to the invention for simulation of wear of functional surfaces of a hip joint, Fig. 6 arrangement of the device according to the invention for simulation of strain of the knee-joint with applied total substitution, and Fig. 7 arrangement of the device according to the invention for simulation of chewing motions and loading of the teeth and mandible.

Examples of embodiment

The device for mechanical testing of functional segments 4 of human body comprises art least two fixation plates 1, which are on their outer circumference connected with ends of angle-wise arranged linear drives 2. The fixation plates 1 are parallel in basic position. The linear drives 2 are coupled with the source of energy and they are further linked with not shown control device. To improve fastening of the tested part of human body the fixation plates 1 are in their centre section provided with the through hole 10, to which are assigned the fastening means 3 of the tested functional segment 4 of human body. The testing space for the tested functional segment 4 of human body is thus situated in an inner space delimited by the fixation plates 1 and the linear drives 2. In case of need, the device may comprise more than two fixation plates 1, while each two neighbouring fixation plates 1 are on their outer perimeter connected by means of a system of angle-wise arranged linear drives 2 coupled with the control device. In this way represent each two neighbouring fixation plates 1 in principle an autonomous system, at which the fixation plates 1 are arranged between the outer fixation plates 1_ an integral part of two neighbouring autonomous systems as it is schematically represented in Fig. 1. From the point of view of production as well as utilisation it may be advantageous if the fixation plates 1 are of a circular shape, while they are in their centre section provided with a circular through hole Ij) with fastening elements 3 for the tested functional segment 4 of human body and on their outer perimeter they are provided with connection elements 30 for repeated removable attachment of ends of linear drives 2. In this way is in principle created a kit, which is applicable for testing of wide range of properties of various types of functional segments 4 of human body, as will be described in examples of embodiment in further text.

In Fig. 2 is represented application of the device according to the invention for simulation of movement and loading of one spinal segment. The device comprises a pair of circular fixation plates λ_, which are parallel in basic position, and which are provided with a centre through hole 10. To the through holes 10 are assigned suitable bar fastening elements 3, in which is by their

ends fastened the spinal segment. The fixation plates λ_ are connected by means of six angle-wise arranged linear drives 3, which are coupled with not shown control device. Spinal segment, namely its tested section, is situated in a space delimited by fixation plates 1 and the linear drives 2. Individual components of the resultant motion are generated by a simultaneous control of all linear drives 2. The control device controls the individual linear drives 2 so that the required resultant motion of the tested area of the spinal segment is achieved (flexion, extension, lateral-flexion, torsion and their mutual combinations). Fig. 3 represents usage of the device according to the invention for a simultaneous simulation of motion and loading of the spinal specimen consisting of several spinal segments. The device comprises four circular fixation plates 1, which are parallel in a basic position, and which are provided with the centre through hole tO. Through the through holes tO passes along the whole device a multi-segment spinal specimen, while the individual segments are at their passing through the holes 10 in fixation plates 1 fastened by the bar fastening elements 3 assigned to these holes 10. Each two neighbouring fixation plates 1 are connected by means of six angle-wise arranged linear drives 3, which are coupled with not shown control device. The whole multi- segment spinal specimen or its tested section is situated in a space delimited by the outer fixation plates 1 and the linear drives 2. The individual components of the resultant motion are generated by simultaneous control of all linear drives 2. The control device controls individual linear drives 2 connecting the individual fixation plates 1 so that the required resultant motion of the whole multi- segment spinal specimen is achieved (flexion, extension, lateral-flexion, torsion and their mutual combinations). The resultant motion along whole length of the multi-segment spinal specimen is determined by a mutual motion of each neighbouring pair of fixation plates ±.

Fig. 4 represents application of the device from the Fig. 3 for simulation of the motion and loading of a multi-segment spinal specimen with applied fixator 5. From results of tests performed according to the Fig. 4 and according to the Fig. 2 or 3 it is then possible to evaluate much better an impact of the

fixator to the spinal specimen and this knowledge may be further utilised e.g. at development of new fixators possibly at modifications of existing fixators.

Fig. 5 represents application of the device from the Fig. 2 for simulation of wear of total hip joint prosthesis. A pair of circular fixation plates 1 with the centre through holes 10, which are parallel in a basic position.Js connected by means of six linear drives 2, which are coupled with the control device. In the fastening elements 3, which are assigned to the holes 10 in the fixation plates λ_ is fastened a specimen of hip joint. The control device controls individual linear drives 2 so that in the hip joint is achieved the required resultant motion. After a simple modification the device according to the invention may be applied for testing the total hip joint prosthesis.

Fig. 6 represents application of the device from Fig. 2 for simulation of motion and strain of the knee joint, possibly of the knee joint with applied fixator. A pair of circular fixation plates λ_ with the centre through holes 10, which are parallel in basic position, is connected by means of six linear drives 2, which are coupled with the control device. As the knee joint is larger than the specimens tested in examples of embodiment in Fig. 2 to 5, the linear drives 2 used here are of a greater length than in examples of embodiment in Fig. 2 to 5. By usage of linear drives 2 always of a suitable length, it is possible to change actually size of the testing space for a specimen delimited by the fixation plates 1 and linear drives 2. In the bar fastening elements 3 that are assigned to the holes 10 in fixation plates 1 is fastened a specimen of the knee-joint. Control device controls individual linear drives 2 so that the required resultant motion in the knee-joint is achieved. Control device is able to control the linear drives 2 so that not only the required resultant motion of the knee-joint, but also acting of passive elements - ligaments, is achieved.

Fig. 7 represents application of the device according to the Fig. 6 for simulation of chewing motions and loading of mandible, possibly of individual teeth. A pair of circular fixation plates 1 with the centre through holes 10, which are parallel in basic position, is connected by means of six linear drives 2 coupled with the control device. As the specimen is larger than the specimens tested in examples of embodiment in Fig. 2 to 5, the linear drives 2 used here

are of a greater length than in examples of embodiment in Fig. 2 to 5. In the bar fastening elements 3, which are assigned to the holes 10 in the fixation plates 1, is fastened the specimen of a skull with jaw-bone and teeth. In the represented example of embodiment are the holes 10 in the fixation plates 1 of a greater size because the tested specimen is larger. A suitable selection of the size of holes 10 in the fixation plates 1 in cooperation with a suitable length of linear drives 2 enables an immediate adaptation of the testing device to the size of currently tested specimen - the skull. Control device controls individual linear drives 2 so that is achieved the required resultant motion of the mandible and/or the required force loading of teeth, etc.

For the invention it is generally valid, that through selection of the size and shape of the fixation plates 1, through selection of the size and shape of holes 10 in the fixation plates, of fastening elements 3 and selection of length of linear drives 2 connecting each two neighbouring fixation plates 1, it is always possible to create an optimum, exact and entirely variable testing device for each particular tested specimen. It is also possible to use a different number of linear drives 2 than the represented six ones between each pair of fixation plates 1. If needed, it is also possible that the individual neighbouring fixation plates 1 are connected by means of linear drives of a different length, so that the distance of each two neighbouring fixation plates 1 may be different.

Industrial applicability

The device for mechanical testing of functional segments 4 of human body is applicable in medical and biomechanical sphere to determine the mechanical properties of elements of human body, for testing of produced commercial fixators and substitutions from the point of view of their optimal application in a respective clinical case.

The device for mechanical testing of functional segments 4 of human body is also applicable in a production - technical sphere as a testing device for designers and producers of medical technology, providing possibility to simulate the loading of segments 4 of human body during their motion.