Reaming device with CFK shaft and with molded interface element

ES 2 379 995 T3

DESCRIPTION

Reaming device with CFK shaft and with molded interlocking element

FIELD OF THE INVENTION

The present invention relates to a reaming device and, in particular, to a reaming device that provides a secure connection between a shaft and an interconnecting element.

BACKGROUND OF THE INVENTION

Intramedullary nailing is the preferred procedure for fixation of long bone fractures, particularly long limbs. In order to fully access the intramedullary canal, a shaft of a reamer has to be flexible enough, in a flexion direction, to contour the soft tissue and the curvature of the bones, and also has to be rigid enough to transmit torque to reamer head.Prior art reaming devices have a propeller shaft design in which debris can be retained during the reaming procedure, so cleaning the reaming device in hospitals before the next use is difficult. , in particular, as regards a sterilization procedure. Proper cleaning of the instrument in hospitals requires great effort and time-consuming. In addition, some hospitals are not prepared to clean these essential devices due to the great effort involved.

In some prior art reaming devices, a helix shaft is replaced by a shaft made of so-called nitinol, which is a material that has a high degree of elasticity (superelasticity) to provide sufficient flexibility. Nitinol is an acronym for Nickel TItanium Naval Ordnance Laboratory. Nitinol is the NiTi in intermetallic phase that has a regular cubic crystal structure different from the structure of titanium or nickel. Nitinol comprises approximately 55% nickel and approximately 45% titanium. Due to the fact that the nitinol tree is made from a single tube, it costs less to clean in hospitals. However, recent studies have shown that nitinol material has a catastrophic failure mode. In particular, some reports indicate that, in hospitals, during the reaming procedure the nitinol tree broke into several fragments while operating. Also, nitinol material is a very expensive material.

Thanks to document US2007 / 0015107, an endodontic instrument having an abrasive coating and a process for producing the same is known, in which the endodontic instrument described has a core of a flexible elastic material having a memory of form, in which, in addition, the core has a coating with abrasive particles, in which the core is made of a nickel-titanium alloy or a plastic material, for example, carbon fiber reinforced plastic material.

In CH668690 a probe electrode cable for medical use, eg electrocardiogram test, is described which uses an insulating coating of carbon fiber impregnated plastic as a sheath with a conductor attached to the test equipment.

In WO2009 / 05672 a reaming device with a carbon fiber reinforced bar and an interconnection element is described.

SUMMARY OF THE INVENTION

It can be considered an object of the present invention to provide a safer reaming device.

The object of the present invention is solved by the object of the independent claims. Additional embodiments thereof are incorporated in the dependent claims.

According to an exemplary embodiment of the invention, a reaming device comprises a shaft with a mounting portion, the mounting portion having an outer surface; a layer of carbon fiber; an injection molded interconnect element for mechanical engagement of an external device, the injection molded interconnect element having a mounting portion, wherein the carbon fiber layer extends over the outer surface of the shaft mounting portion and having an outer surface, wherein the outer surface of the carbon fiber layer has a surface structure; wherein the mounting portion of the injection molded interconnect element is injection molded onto the surface structure of the fiber layer

ES 2 379 995 T3 of carbon.

Therefore, the shaft can be provided with an outer surface structure, so that an injection molded interconnecting element can easily be integrally formed on the shaft, that is, the carbon fiber layer that extends over the shaft. Therefore, the shaft can be designed to meet the specific requirements of a shaft, for example flexibility and a specific resistance to breakage, wherein the integrally formed injection molded interconnecting element can be designed to meet the requirements of the shaft. specific requirements for attaching an external device. Such requirements may include, for example, a specific geometry and specific material properties that can be achieved with the injection molded interconnect element.

According to an example embodiment of the invention, the shaft is made of a carbon fiber reinforced material.

Therefore, a specific resistance can be provided to avoid a breakage of a shaft, in particular, since a material reinforced with carbon fiber has a specific elasticity and flexibility, while maintaining the ability to transmit torsional forces and, at the Once, due to the carbon fiber reinforced structure, it does not usually break into many pieces.

According to an example embodiment of the invention, the carbon fiber layer comprises a carbon fiber wrapped with a resin impregnation.

Therefore, the carbon fiber layer can be given a specific shape necessary for molding on the interconnecting element. In particular, the resin impregnation can be a thermosetting resin, so that a specific mold can be heated to fix the resin impregnation of the carbon fiber layer.

According to an exemplary embodiment of the invention, the surface structure of the carbon fiber layer comprises a pressed toothed structure.

Therefore, a secure connection can be established between the shaft and the carbon fiber layer, respectively, on the one hand, and the molded interconnecting element on the other hand. In particular, a toothed structure allows a mechanically safe transmission of forces between the shaft and the interconnecting element.

According to an exemplary embodiment of the invention, the interconnect element comprises a coupling portion for coupling a power tool reamer drive mechanism as an external device.

Therefore, a drive mechanism, or any other mechanical tool, can be coupled to the engaging part of the interconnecting element in order to drive the shaft.

According to an example embodiment of the invention, the coupling part comprises an end part capable of transmitting a torque.

Therefore, a torque from a power tool can be transmitted to the shaft through the interface element. In particular, the end part can be designed as a hexagonal cross section. However, it should be noted that any other angular geometry can also be used. It should be noted that a free-form cross section can also be used, for example having a wavy outer contour. In particular, a unique cross-sectional shape can be used in order to ensure the correct use of a specific tool in conjunction with the corresponding reaming device. That is, the engagement of a desired combination of a reaming device and a corresponding power tool can be established with a unique corresponding engagement geometry between the power tool and the respective engagement part or end part of the interface element.

According to an exemplary embodiment of the invention, the injection molded interconnect element comprises a nominal break geometry or arrangement between its mounting part and its mating part.

Therefore, a predetermined breaking point or weakened section can be set, so that the reaming device will break in said specific section when it exceeds a predetermined torque. In particular, this can prevent unwanted breakage in a position that cannot be

ES 2 379 995 T3 access, for example, near the reaming head. That is, the predetermined break point or nominal break point will be established in a safe and accessible area of ​​the reaming device, so that no broken parts of the reaming device remain on the patient's body.

According to an exemplary embodiment of the invention, the injection molded interconnecting element comprises a molding material that loses shape stability at normal sterilization temperatures.

Therefore, it can be ensured that the reaming device cannot be sterilized without losing its specific geometric properties. This is important if the reaming device is a disposable device. In case the surgeon tried to use the reaming device again, he would have to sterilize the reaming device, however, during said sterilization, the reaming device will be destroyed by default to prevent the reaming device from being used again. It should be noted that the entire interconnecting element can be made of non-heat-resistant material or only specific sections of it can be made of non-heat-resistant material, if using, for example, a two-stage molding process using two different molding materials. It should also be noted that a heat resistant portion may be provided to maintain an "emergency" geometry, which is, however, not a comfortable geometry for surgery. In particular, one component of a multi-stage mold may be heat resistant and the other component of a multi-stage mold may not be heat resistant. Lost shape stability can also be established by the impact of another sterilization parameter, eg steam or the like. Therefore, the interconnect element can be designed to lose its shape stability when treated with steam.

According to an exemplary embodiment of the invention, the injection molded interconnect member comprises a strain indicating pattern that indicates a pre-break strain.

Therefore, the surgeon can directly recognize a critical deformation of the interface element when recognizing the indicator pattern. Said indicator pattern can be, for example, a longitudinal line or a longitudinal groove extending in the longitudinal direction of the interconnecting element. In case the longitudinal line or groove deforms, for example, like a helix, the surgeon knows that a torque is applied or that a specific limit can be exceeded. It should be noted that an interference grid can also be used as a strain indicator pattern, so that, for example, a specific Newton pattern can be produced at specific strain phases, so that a specific Newton pattern can be used as indicator of the degree of deformation.

According to an exemplary embodiment of the invention both the shaft and the interconnecting element have an elongated through hole, in which both through holes are aligned with each other.

Therefore, a guide wire or a tie wire can be inserted into the alignment through holes. A guidewire can be used for better targeting of the reaming device, wherein a tie wire can be used for a reaming head provided on the reaming device.

According to an exemplary embodiment of the invention, there is provided a method of manufacturing a reaming device comprising: wrapping a layer of carbon fiber over an outer surface of a mounting portion of a shaft; pressing a surface structure to an outer surface of the carbon fiber layer; injection molding an interconnect element onto the surface structure.

Therefore, in particular, when using a tree made of a carbon fiber reinforced material, a carbon fiber layer can provide a secure and compatible connection between the carbon fiber layer and the tree, in which the The outer surface structure of the carbon fiber layer establishes a secure mechanical connection between the carbon fiber layer and the injection molded interconnecting element. In particular, such a process allows a reaming device to be manufactured without having too many material stresses during a manufacturing process, since an injection molding provides more or less a material morphology that has little or negligible stresses.

According to an exemplary embodiment of the invention, wrapping comprises impregnating the carbon fiber layer with an impregnating solution compatible with a tree material.

Thus, a secure connection can be established between the tree and the carbon fiber layer.

According to an exemplary embodiment of the invention, the method further comprises preparing a part

ES 2 379 995 T3 assembly of the tree before wrapping a carbon fiber layer to establish a secure connection between the tree and the carbon fiber layer.

Therefore, a kind of priming can be carried out before mounting the wrapped carbon fiber layer to the shaft in order to establish a secure connection capable of transmitting torque.

According to an exemplary embodiment of the invention, pressing includes heat setting the carbon fiber layer in a closed mold.

Therefore, a fast and safe manufacturing procedure can be established. In particular, when using a mold of a thermoplastic material and a thermosetting impregnation for the carbon fiber layer, a defined weakened section can be established that allows a safe transmission of forces and at the same time a predefined weakened section as described. previously.

It should be noted that the above features can also be combined. The combination of the above characteristics can also result in a synergistic effect, although it is not explicitly described in detail.

These and other aspects of the present invention will become apparent from the embodiments described below and will be clarified by reference thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 illustrates a shaft for a reamer before wrapping a layer of carbon fiber.

Fig. 2 illustrates a tree with a wrapped carbon fiber sheath having a surface structure.

Fig. 3 illustrates a cross-sectional view of a shaft with an overmolded interconnect element.

Fig. 4 illustrates an external view of a shaft with an overmolded interconnect element.

Fig. 5 illustrates a schematic flow diagram of a method for manufacturing a reaming device.

DETAILED DESCRIPTION OF EXAMPLE FORMS OF REALIZATION

Fig. 1 illustrates a shaft 10, in particular a reamer shaft having a mounting portion 11. The shaft 10 has an outer surface in which a layer of carbon fiber 30 is wrapped. FIG. 1 illustrates the carbon fiber layer 30 in an unwrapped condition.

Fig. 2 illustrates the end portion of a shaft 10, in which the carbon fiber layer 30 is wrapped around the outer surface of the mounting portion 11. As can be seen in FIG. 2, the carbon fiber layer comprises a surface structure 34 on the outer surface 33 of the carbon fiber layer. Said outer structure can be formed, for example, as a toothed structure or a ridged structure, in which ridges extend along a longitudinal direction of shaft 10. It should be noted that the ridges of surface structure 34 can also extend in a helical manner in order to withstand not only circumferential forces, for example torsional forces, but also forces in a longitudinal direction of the shaft, such as pushing or pulling forces. It should be noted that the surface structure 34 can also have any other structure capable of transmitting forces from the shaft 10 to an interconnecting element 20 or vice versa.

Fig. 3 illustrates a cross sectional view of the end section of a shaft 10 provided with an overmolded interconnect element 20. Interconnect element 20 has a mounting portion 21 that meshes with the surface structure of the outer surface of the fiber layer of carbon 33, 34. Thus, forces can be transmitted from shaft 10 to interconnect member 20. Both the interconnecting element 20 and the shaft 10 can comprise a through hole 19, 29, respectively, through holes that can be aligned. Therefore, a guide wire or a tie wire can be inserted through the alignment through holes 19, 29 to guide the reaming tool and the reaming procedure, as well as to secure, for example, a reaming head that will be mounted on the other end section of the shaft (not shown). The injection molded interconnect member 20 may comprise a nominal break section 26, which may be, for example, a slot or a notch. Since the interconnecting element 20 also comprises a coupling part 25, the nominal breaking point section 26 can be provided,

ES 2 379 995 T3 on the one hand, between the mounting part 21 and, on the other hand, the coupling part 25. The coupling part 25 can serve to couple a power tool or a driving tool to drive the reaming device . By providing the rated failure section 26 between the coupling portion 25 and the mounting portion 21, a torsional overload can result in a predefined failure of the rated failure section 26. Since said section 26 can be designed as the most weakened section with respect to a torque of the entire reaming device, a predefined failure of the nominal section 26 prevents a failure of a more critical section, such as near the head. reamer or shaft that is inserted into the patient's body. Therefore, should the reamer break, the nominal break section provides a break position outside of the patient's body. The coupling portion 25 may further comprise a specific geometry to transmit torsional forces, for example, the outer shape of a hexagonal cross section, in order to transmit torsional forces. However, a specific cross-sectional shape can also be selected, which can be a single cross-sectional shape that only fits the corresponding power tool. Therefore, it can be avoided that a mismatched combination of a reaming device and a power tool is used.

The material of the injection molded interconnect element can be a material that loses its outer shape when exposed to normal sterilization temperature. This can be important when providing a disposable reaming device. Therefore, if an attempt is made to sterilize the reaming device, the outer shape of the interface member loses its predetermined shape, so that the reaming device cannot be used again. Therefore, a reuse of a reaming device intended to be disposable can be avoided.

Fig. 4 illustrates the end portion of a reaming device 1 having a shaft 10 and an injection molded interconnect element 20. The injection molded interconnect element 20 may be provided with a strain indicating pattern 28. Said strain indicating pattern deformation 28 can be, for example, a line extending in the longitudinal direction of the reaming device. Should the reaming device interface member become deformed, the deformity indicating pattern would also deform considerably, so that a surgeon would recognize the deformity. In particular, when no torque is applied to the interconnecting element, the shape of the strain indicating pattern can be used as an indicator of a deformation of the interconnecting element, even if no torsional forces are applied. If the interconnect element is deformed, for example, it cannot be used anymore. Said deformation indicator pattern can also be, for example, an interference mesh or an interference grid, so that, depending on the deformation, several specific interference patterns can be produced, an interference pattern that can be used as an indicator of the intensity of the deformation. This is illustrated by numbers 28a and 28b. The pattern 28a is, for example, slightly inclined with respect to the longitudinal axis of the reaming device or the interconnecting element 20, where the second pattern 28b has an inclination in the opposite direction. When, for example, these two patterns 28a and 28b are provided with an intermediate layer, so that the deformation, for example, increases the slope of the first pattern 28a and decreases the slope of the pattern 28b, a natural interference pattern can be used as a sole indication of the degree of deformation.

Fig. 5 illustrates a schematic flow of a method for manufacturing a reaming device. In step S10, the surface of the tree can be prepared to provide improved adhesion of the carbon fiber layer 30. Such a process can be considered a kind of priming process. In step S20, the carbon fiber layer is wrapped on an outer surface of a mounting part of a shaft. Said wrapping may optionally comprise a process of impregnating the carbon fiber layer with an impregnation solution, in order to increase the adhesion between the shaft 10 and the carbon fiber wrapping 30. In a later step S30, a surface structure It will be pressed on the outer surface of the carbon fiber layer. This can be carried out for example with a hot mold and the use of a thermoset resin, so that step S30 can optionally include a heat setting procedure in step S35. Finally, an interconnect element 20 is injection molded onto the surface structure of the carbon fiber layer.

It should be noted that the term "comprising" does not exclude other elements and that the terms "a", "one" or "one" do not exclude a plurality. Likewise, elements that have been described associated with the different embodiments can be combined.