FI78238C - Surgical osteosynthesis device - Google Patents

Description

1 78238

Surgical osteosynthesis device

The invention relates to a surgical osteosynthesis device as further defined in the preamble of claim 1.

More specifically, the invention provides osteosynthesis devices or parts thereof, such as plates, screws, beams, nails, or pins, made from a combination of materials that are resorbable (soluble) under tissue conditions such that the osteosynthesis media or components thereof are layered.

Tissue-soluble materials and osteosynthesis devices made therefrom have been disclosed in several patent publications, e.g. U.S. Patents Pat. 3,463,158, U.S. Pat. Pat. 3,620,218 and U.S. Pat. Pat. 3,739,773, which disclose polyglycolic acid core nails, osteosynthesis plates, screws, and hollow cylinders. In G.B. Pat. 1,034,123 discloses osteosynthesis devices made of poly-β-hydroxybutyric acid and poly-β-hydroxypropionic acid. U.S. Pat. Pat. 4,052,988 discloses surgical instruments made of poly-p-dioxanone. U.S. Pat. Pat. No. 4,279,249 discloses composite surgical instruments consisting of reinforcing structures made of polyglycolic acid housed in a matrix consisting of polylactide or a copolymer thereof containing at least 90% of its units of lactic acid units.

The hardnesses and stiffnesses of the resorbable materials vary over a wide range. For example, polyglycolides, polylactides and polyhydroxybutyric acid are relatively rigid materials and thus also notch sensitive and break relatively easily in bending (bending strengths 40-60 MPa). For example, poly-p-dioxanone and many of its derivatives, on the other hand, are soft, flexible (elastic) and tough materials that often do not break at all in a normal bending test.

Surgical devices for osteosynthesis require both rigidity and toughness under operating conditions. The present invention provides surgical osteosynthesis devices that are three-dimensional bodies, such as plates, screws, beams, nails, or pins, characterized by a layered composite structure consisting of resorbable layers of material having different stiffness so that the composite , a flexible resorbable polymeric material and the underlying layer consists of a clearly stiffer re-20 sorbable material, the core of which may again be flexible in structure. Utilizing the composite structures of the invention, it is possible to advantageously combine the good properties of flexible and rigid resorbable polymers for surgical applications and to eliminate the disadvantageous mechanical properties of individual materials in the manufacture of macroscopic surgical articles for the treatment of fractures and dislocations.

30

In order to achieve the above objects and to eliminate and reduce the disadvantages of the prior art, the device according to the invention has been given the main features which appear from the feature part of claim 35.

3,78238 When used in a resorbable macroscopic surgical device, the composite structure of the invention reduces the notch sensitivity of the body with a flexible and pliable surface layer and thus improves the toughness of the composite body. On the other hand, the rigid layer gives the macroscopic body the bending stiffness required for applications. From the point of view of bending stiffness and at the same time tensile strength, a particularly preferred embodiment is such a composite body in which the core of the rigid layer is also flexible and pliable. In this case, the rigid resorbable material forms a tubular structure which is advantageous in terms of bending stiffness and, on the other hand, the flexible and pliable core increases the tensile strength of the body.

15

In addition, biostable and / or resorbable fibers can be used in different layers as reinforcements in the composite bodies according to the invention, or the 20 ns described in the publication publication FI 75493 can be applied in different layers. itselujitusperiaatetta.

The invention and its functionality are illustrated by the following Figures 1a-b.

Figure 1a shows some layered composite bodies according to the invention. This is a cross-section of a cylindrical and rectangular osteosynthesis device or a part thereof such as a plate, a core nail or an osteosynthesis beam 30 (FI-69402) consisting of a flexible and flexible resorbable material. biostable and / or re-35 sorbable reinforcing fibers or the surface layer and / or the inner part of 4,78238 may be made on a self-reinforcing principle (e.g. by sintering or partially melting from a fibrous material). Figure Ib shows a cross-section of a cylindrical and rectangular resorbable osteosynthesis device 5 or a component thereof, in which, in addition to the flexible and pliable resorbable surface part 1 and the rigid resorbable inner part 2, the flexible composite body 10 also has and / or resorbable fibers.

Flexible polymers suitable for surgical purposes as pin 1 of the pin-15 and core 3 of the osteosynthesis devices according to the invention are, for example, poly-p-dioxanone and its derivatives and, in general, polymers made from the monomer: R-CH C = O II, RCR HC -R '(where R and R' may be hydrogen, methyl or ethyl). Further suitable for this purpose are long chain molecular weight polyester amides (PEA) which are copolymers of diamine, hydroxy acid and diacid. Among the PEA polymers (U.S. Pat. 4,343,931), polymers having the following repetitive chemical structure are suitable for the osteosynthesis devices according to the invention, for example: 5 78238 0 0 0 NH-C-CH 2 -O-C- (CH 2) -C- (Structural Formula I) 5 wherein x is e.g. 11-14, with melting points of the polymers ranging from 80-100 ° C.

Suitable materials for the rigid inner part 2 are, for example, polyglycolides, polylactides, glycolide / lactide copolymers and poly-β-hydroxybutyric acid.

The invention is illustrated by the following examples.

15 EXAMPLE 1

Polyglycolic acid melt (intrinsic viscosity | n | = 1.2 in 0.5% hexafluoroisopropanol solution (T

20 = 25 ° C), melting point Tm = 224 ° C) were prepared by injection molding cylindrical rods (length 70 mm, diameter 4 mm). The rods were coated with a 0.25 mm thick layer of poly-p-dioxanone (intrinsic viscosity | n | = 0.80 in 0.1% tetrachloroethane solution (T = 25 ° C, melting point T = 110 ° C) in an injection mold to give a thickness of 4.5 mm. cylindrical resorbable layered composite rods a.

30 EXAMPLE 2

Surgical wound sutures made of polyglycolic acid (trade name Dexon, size 2-0) were prepared in a compression press by sintering cylindrical rods (length 70 mm) reinforced with it-35 at 220 ° C.

6 78238 diameter 4 mm). The rods were spray-coated using a 0.25 mm thick layer of poly-p-dioxanone (| n | = 0.8, Tm = 110 ° C) to give 4.5 mm thick resin-absorbable composite rods with a thickness of 4.5 mm.

EXAMPLE 3

From the melt of polyglycolic acid (| η | = 1.2, Tm = 224 ° C) 10 tubular bodies (length 70 mm, outer wall diameter 4 mm, inner diameter 1.5 mm) were made by injection molding. Poly-p-dioxanone was injection molded into the inner channel and the outer surface of the tubes to obtain cylindrical resorbable layered composite rods with a thickness of 4.5 mm (cf. Fig. Ib).

EXAMPLE 4 From wound sutures made of a polyglycolide / lactide copolymer, polylactin 910 (trade name Vicryl) was prepared in a compression press by sintering at 180 ° C tubular self-reinforced resorbable bodies (length 70 mm, outer wall diameter 25 mm, inner diameter 25 mm). Poly-p-dioxanone was injection molded into the inner channel and outer surface of the tubes to obtain 4.5 mm thick cylindrical resorbable layered composite rods.

30 EXAMPLE 5

From wound sutures made of polyglycolide / lactide copolymer, polylactin 910 (trade name Vicryl) 35 was prepared by compression molding at 180 ° C

1 78238 tubular self-reinforced resorbable bodies (length 70 mm, outer wall diameter 4 mm, inner diameter 1.5 mm). Poly-5 esteramide (structural formula I, where x = 12) was injection molded into the inner channel and the outer surface of the tubes to obtain 4.5 mm thick cylindrical resorbable layered composite rods.

Claims (7)

A surgical osteosynthesis device or part thereof such as a plate, beam, nail, pin or screw, consisting of a three-dimensional solid composite body made of a resorbable tissue-adaptable polymer or polymers, and consisting of resorbable materials having different material properties, resorbable materials having different material properties. or a part thereof comprising a flexible, resilient, resorbable surface layer (1) and a resorbable rigid inner part (2) surrounded by the surface layer (1), optionally at least one of the material layers (1-3) of the composite osteosynthesis device or part thereof contains resorbable and / or biostable reinforcing structures. The osteosynthesis device or part thereof according to claim 1, characterized in that the inner part (2) comprises a resorbable, flexible and flexible core (3), optionally at least one of the material layers (1-3) of the composite osteosynthesis device or part thereof contains resorbable and / or biostable reinforcing structures. 20 An osteosynthesis device or part thereof according to claim 1 or 2, characterized in that the surface layer (1) and / or the core (3) is made of a polymer containing at least units having the following structural formula: R 'R R »III (C-CH-O-C-CH-O) n 1 R 30 wherein R' and R may be hydrogen, methyl or ethyl and n = degree of polymerization. Osteosynthesis device or part thereof according to Claim 1, characterized in that the surface layer (1) and / or the core (3) are made of a copolymer of poly-p-dioxanone. 9,78238 Osteosynthesis device or part thereof according to Claim 1 or 2, characterized in that the surface layer (1) and / or the core (3) is made of polyesteramide (structural formula I). 5 Osteosynthesis device or part thereof according to one of Claims 1 to 5, characterized in that the at least partially resorbable rigid inner part (2) surrounded by the flexible surface layer (1) is made of polyglycolide or polylactide or a copolymer thereof or poly-β-hydroxybutyric acid. . The osteosynthesis device or part thereof according to claim 2, characterized in that the reinforcing structures are films, film fibers, fibers, yarns, braids or the like or structures constructed therefrom. 10,782 38 Patent Scrap;