DE202019100501U1 - prosthetic arm - Google Patents

Abstract

Arm prosthesis, comprising a shaft (1) with proximal end (10) and distal end (11) and an artificial hand (2) attached to the distal end (11), characterized in that the shaft (1) in an additive process of at least a plastic material is produced and a tensioning device is provided, by means of which a radially inwardly directed adjustable clamping force on the shaft (1) can be generated in order to radially compress the shaft (1) reversibly.

Description

The invention relates to an arm prosthesis comprising a shaft having a proximal end and a distal end and an artificial hand attached to the distal end.

Arm prostheses of the type described above are known, including on the DE 10 2016 201 002 A1 by way of example. They serve to care for a patient who, for example, has only an arm stump due to an amputation.

The shaft of the arm prosthesis is applied to the amputation stump or placed over this and fixed, where it has already been proposed to make an individual adaptation of the shaft manufacturing in an additive method based on obtained 3D data of the amputation stump.

As a rule, arm prosthesis stems are funnel-shaped due to the shape of the stump, since the arm is usually thicker at the proximal end than at the distal end. This allows the patient to enter the shaft of the arm prosthesis. By a frictional contact with a prosthetic liner, which is first applied as an inner layer on the arm stump, the prosthesis socket sits firmly on the arm stump. Over the course of a day, however, the circumference of the arm stump changes due to, for example, physical exertion and normal volume fluctuations. These can not be easily compensated in the known prosthetic arm and there is a risk that the prosthesis wearer loses the arm prosthesis.

In addition, if the prosthetic arm is myoelectrically formed and has sensors that derive electrical signals from the skin of the arm stump and lead to drive means of a motorized artificial hand connected to the stump, such volume fluctuations can also cause the sensors no longer as desired abut the skin surface and it comes in this respect to malfunction or a faulty controllability of the artificial hand.

In addition, it is more common that during amputation, part of the wrist and / or hand bones have not been amputated or the stump is not approximately conical. In such a case remains at the end of the arm stump thickening back, which makes it difficult to produce the necessary contact closure of the prosthesis stem with the stump or tighten the prosthesis stem even beyond such an undercut.

The object of the invention is therefore to propose an arm prosthesis of the type mentioned above, which has a significantly improved shaft, which can be adapted exactly and easily to the stump even in difficult conditions, easily and without additional help from the patient. and can also be adjusted to the volume differences occurring during the wearing period.

To achieve the object, according to the invention, the embodiment of an arm prosthesis according to the features of the protection claim 1 proposed.

Advantageous embodiments and modifications of the invention are the subject of the dependent claims.

The invention proposes that the shaft is made in an additive process of at least one plastic material and a tensioning device is provided, by means of which a radially inwardly directed adjustable clamping force can be generated on the shaft to reversibly radially compress the shaft.

In the context of the invention, it is thus possible, in particular in accordance with a previously created on the arm stump of a patient 3-dimensional model of the same to produce exactly this arm stump shank in an additive process that is elastically resilient and in particular elastically expandable, so that the shaft also with a non-conical stump or a thickening at the end of the arm stump can be easily tightened by temporary expansion. Subsequently, a desired radially inwardly directed clamping force is generated by the clamping device on the regions of the shaft which are separated from one another by the slot and this is radially compressed until the firm and exact seating of the shaft on the arm stump is achieved.

In the context of the invention, it is provided that the clamping force executable by the clamping device is adjustable and reversible, for example by appropriate adjustment, so that the patient individually determine the clamping force itself and readjusting volume changes occurring during the period of wear and can also cancel, such as when the arm prosthesis should be stored.

According to one proposal of the invention, the shaft comprises, starting from the proximal end, at least one slit extending longitudinally towards the distal end and open towards the proximal end and terminating in front of the distal end. By means of the clamping device is then the clamping force on the exercised adjustable by the at least one slot separated areas.

In an alternative embodiment of the invention it is provided that the shaft is formed from a plurality of interconnected ring elements of the plastic material, which are also produced additively in this configuration. Such a substrate is structurally similar to a chain mail, but is made of ring elements made of the plastic material and can compensate for volume fluctuations in all directions due to the elastic material properties and also radially compressible adjustable via the clamping device.

According to one proposal of the invention, the clamping device may be formed by a tensioning ratchet fastened on the outside of the shank and a tensioning cable extending around the shank, the at least one end of which is adjustably wound onto the tensioning ratchet. Such tension ratchets are known and are used for example in sports shoes, such as ski boots and inline skates as tensioning device. In this case, either one end of the tensioning cable is fixed in place and only the other end is variably wound on the tensioning ratchet or both ends of the tensioning cable are equally wound on the tensioning ratchet.

As a result of the invention provided for the production of the shaft of a plastic material in an additive process, such as 3D printing opened according to a further proposal of the invention, the possibility of guide channels for the tensioning cable at least partially on and / or in the surface of the shaft integral in the production of the shaft train. Seen from the outside of the arm prosthesis according to the invention her then run the tensioning cables of the clamping device almost completely hidden within the shaft.

In addition, according to a further proposal of the invention due to the additive manufacturing process and hollow chambers for receiving electrodes, batteries, conductors, actuators or other components can be integrally incorporated into the shaft, which are integrated in this way extremely efficient and unobtrusive in the arm prosthesis according to the invention.

By using electrically conductive plastic materials, moreover, electrically conductive structures for forming electrodes and / or printed conductors can also be produced directly during the additive production of the arm prosthesis according to the invention.

It can also slip-resistant inserts, such as silicone pads are incorporated into the inner surface of the shaft to prevent slippage of the arm prosthesis.

The shaft of the arm prosthesis according to the invention can be designed, for example, as an inner shaft and an outer shaft is provided, for example, in skin-colored coloring, which is positioned over the inner shaft as an outer shell. It is also conceivable to design such an outer sheath equally when producing the arm prosthesis according to the invention in the additive method.

By using a gradient material, i. Moreover, plastics of different hardness and / or elasticity may be formed with portions of the shank having mutually different hardness and / or elasticity, although the shank has been produced integrally in an additive process. For example, a flexibility that increases from the distal end to the proximal end can be adjusted with such a gradient material. Both requirements for the anatomical adaptability of the inner shaft and the rigid, shock and dimensionally stable design of the outer shaft can be taken into account.

According to a further proposal of the invention, the shaft can also have a structure of additively and integrally formed inner and outer layers, wherein the inner and outer layers are connected on the edge side or in each case as a closed layer, so that an air-filled cavity is formed within the shaft , which is bounded by the inner layer, the outer layer and possibly its edge-side connection, such that the inner layer and the outer layer together enclose the air-filled cavity. Within this cavity, a plurality of elastically deformable support elements is arranged, which maintain the cavity between the inner and outer layer and allow due to their elastic deformability a corresponding elastically resetting deformation of the inner layer relative to serving as an abutment rigid or dimensionally stable outer layer. In addition, air passage openings are formed in the space between the individual support elements, which may be discrete, for example, so that upon elastic deformation of the inner layer and / or the support elements, the air present in the cavity is temporarily displaced and can escape to other areas of the cavity. Finally, at least one suitable position, preferably in the region of the outer layer, at least one ventilation opening can be provided, via which the air-filled cavity of the shaft with the surrounding atmosphere communicates so that an air exchange between cavity and ambient atmosphere can take place. By forming the inner and outer layer and / or some or all support elements made of plastic material of different properties, the behavior of the shaft thus formed can be adjusted within wide limits. The structure of such a material is for example from the DE 20 2017 106 997 U1 known.

To produce such an arm prosthesis, the preparation of a three-dimensional digital model of the patient's arm stump to be supplied can be carried out in a first step, which can be effected, for example, with known digitizing methods, such as a strip light scanner. Previously, the points for the later position of the sensors on the muscles are marked, the edge of the shaft marked and the positions of the batteries or other components indicated. The thus created digital scan can then be digitally modeled on the screen.

Subsequent to these preparatory actions, a digital CAD design of the three-dimensional model of the prosthetic arm and in particular of the individual shaft can be performed in a suitable CAD system on the basis of the present virtual model. The positions of electrodes, batteries, conductors, actuators, further components as well as possibly provided slots are defined here or adopted from the previous specifications and deposited equally in the three-dimensional model.

Subsequently, the arm prosthesis can be made in accordance with the 3-dimensional model in an additive process of a plastic material, wherein the fixed guide channels for the tensioning cable and the hollow chambers for receiving electrodes, batteries, conductors and / or actuators are integrally incorporated or electrodes and or conductor tracks be produced by using electrically conductive materials directly in the additive manufacturing process.

By inventively provided design of the shaft, the frequently occurring volume fluctuations can be compensated by readjustment of the clamping device and so slipping of the shaft can be prevented. After the prosthesis wearer has tightened the shaft in the open state, he can use the tensioning device to narrow the shaft to a good fit. In the course of a day, the natural volume reduction of the stump can be compensated by further closing the shaft. This also ensures the functionality of the myoelectric prosthesis, as the sensors are pressed against the associated muscles. Furthermore, there is the possibility to prevent slipping by compression in advance.

• 1 eine erfindungsgemäße Armprothese in perspektivischer Darstellung;
• 2 den Schaft der Armprothese gemäß 1 in weiteren Einzelheiten.

Further embodiments and details of the arm prosthesis according to the invention are explained below with reference to an embodiment illustrative drawing. Show it:

• 1 an arm prosthesis according to the invention in a perspective view;
• 2 the shaft of the prosthetic arm according to 1 in more detail.

From the 1 is an arm prosthesis 1 visible, over a shaft 1 with proximal end 10 and distal end 11 and one to the distal end 11 attached art hand 2 features.

The shaft 1 is in an additive process of a suitable plastic, for example PA 12 Its design was made exactly in accordance with a previously created 3-dimensional scan of the arm stump on which the shaft 1 is raised.

Starting from the proximal end 10 and to this are also open in the longitudinal direction to the distal end 11 slits running out 12 provided, namely at diametrically opposite areas, as shown in the detailed illustration 2 seen. However, the slots end at about 4/5 of the total length of the shaft 1 in front of the distal end 11 ,

Through the slots 12 becomes the shaft 1 in two in the area of the distal end 11 subdivided half shells and thus can be easily widen when tightening on the stump, not shown. Subsequently, the half shells by a clamping device in the form of a suitable position on the shaft 1 arranged tensioning ratchet 13 fixed on which the ends of a tensioning cable 14 Adjustable and reversibly detachable wound. After applying the shaft, it is thus possible by operating the tensioning ratchet 13 and shortening the circumferential tensioning cable 14 exert a radially inwardly directed clamping force, which is the temporary widening of the shaft 1 picks up and fixes it on the stump with the desired clamping force. This tension can easily be readjusted by the user during the wearing period. To remove the shaft 1 becomes the tension ratchet 13 dissolved, so a renewed expansion of the shaft 1 is possible.

As in more detail from the 2 can be seen, are the Spanseile or with its two ends to the tensioning ratchet 13 guided single tension cable 14 in guide channels 17 led that due to the additive production of the shaft 1 are integrally incorporated on or in the surface of the shaft and already in the construction of the shaft 1 be determined and taken into account.

Likewise, in the stem preferably made in an additive process 1 also cavities for receiving electrodes 15 , a battery compartment 16 incorporated for receiving rechargeable batteries or batteries and unillustrated conductor tracks, so that the arm prosthesis can be made myoelectric and thus the artificial hand 2 in accordance with the at the sensors 15 can be moved from the skin surface tapped current pulses. Also, associated drive motors can be provided in corresponding cavities. Finally, with the use of electrically conductive materials for the additive manufacturing process, it is also possible to integrally integrate conductor tracks, sensors and the like directly during the manufacture of the shank. The material is given locally conductive properties during the manufacturing process. In the same way, other properties, eg mechanical, thermally conductive / insulating, hydrophobic / hydrophilic, can be influenced locally or globally via the chemical composition. As an additive manufacturing process, for example, a method according to WO 2018/022034 A1 and WO 2018/017096 A1 ,

The above-explained arm prosthesis is thus easily individualized maximum and thus manufactured with the highest accuracy of fit and can easily by the slots provided in the shaft even with difficult geometry of the arm stump on and off and can easily with respect to the applied clamping force on the stump in the applied state adapted to the individual's feelings and changed circumstances.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102016201002 A1 [0002]
• DE 202017106997 U1 [0022]
• WO 2018/022034 A1 [0033]
• WO 2018/017096 A1 [0033]

Claims (10)

Arm prosthesis, comprising a shaft (1) with proximal end (10) and distal end (11) and an artificial hand (2) attached to the distal end (11), characterized in that the shaft (1) in an additive process of at least a plastic material is produced and a tensioning device is provided, by means of which a radially inwardly directed adjustable clamping force on the shaft (1) can be generated in order to radially compress the shaft (1) reversibly. Arm prosthesis after Claim 1 , characterized in that the shaft (1) starting from the proximal end (11) has at least one slit (12) extending longitudinally towards the distal end (11), open towards the proximal end (10) and in front of the distal end (11) ends and by means of the clamping device, the clamping force on the at least one slot (12) separated areas is exercisable. Arm prosthesis after Claim 1 , characterized in that the shaft (1) is formed from a plurality of interlaced ring elements of the plastic material. Arm prosthesis after one of Claims 1 to 3 , characterized in that the shaft is shaped in accordance with a three-dimensional model. Arm prosthesis after one of Claims 1 to 4 , characterized in that the shaft (1) is formed of multiple layers of the same or different plastic materials or of a gradient material with regions of different hardness and / or elasticity. Arm prosthesis after one of Claims 1 to 5 , characterized in that the tensioning device is formed by a clamping ratchet (13) fastened on the outside of the shaft (1) and a tensioning cable (14) running around the shaft (1), the end of which is adjustably wound on the tensioning ratchet (14). Arm prosthesis after Claim 6 , characterized in that guide channels (17) for the tensioning cable (14) at least partially on and / or in the surface of the shank (1) are integrally formed. Arm prosthesis after one of Claims 1 to 7 , characterized in that in the shaft (1) hollow chambers for receiving electrodes (15), batteries, conductor tracks and / or actuators are integrally incorporated. Arm prosthesis after one of Claims 1 to 8th , characterized in that electrically conductive structures for the formation of electrodes and / or conductor tracks are additively integrated in the shaft (1). Arm prosthesis after one of Claims 1 to 9 , characterized in that the shaft (1) is designed as an inner shaft and an outer shaft is provided, which can be positioned over the inner shaft as an outer shell.

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