RU2614212C2 - Suture material - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: suture material contains a thread/(threads) of the superelastic NiTi. The suture material structure further includes a thread/(threads) made of an alloy with the following composition: 45% of titanium, 0.5% of molybdenum, 1.5% of iron, the rest - nickel. The diameter of the applied threads is selected from the range of 30-60 microns.

EFFECT: increased handling quality of the suture material.

3 dwg

Description

The invention relates to medical equipment.

Suture material is one of the main technical means of surgery. Along with the surgeon’s ability, the viability of the operation performed depends to a large extent on his quality. Therefore, the improvement and search for new materials constitute a separate area of development of medical equipment.

A variety of surgical tasks prescribes the corresponding specificity of the functional qualities of the suture material used.

So, the traditional suture material of natural origin - catgut - is characterized by good handling quality, high strength and stability of the node. Its disadvantages include high absorption capacity and the reactogenicity associated with it, allergenicity, and disinfection complexity (Bulletin of the Russian Association of Obstetricians and Gynecologists // Scientific and Practical Journal, 1996. No. 1, pp. 30-31).

Similar disadvantages are inherent in non-absorbable suture material from the material of multifilament silk threads (the same source).

These shortcomings are less characteristic of modern suture materials obtained on the basis of synthetic polymers (G.M. Semenov, V.L. Petrishin, M.V. Kovshova, etc.), as well as metallurgical technology. Of the latter, the most universally satisfying functional requirements is suture material from alloys based on titanium nickelide (RF Patent No. 2144385). The wide range of functional advantages of this material is due to the properties of martensitic alloys, which include titanium nickelide, that are unusual for modern engineering. The most important of these are superelasticity, cyclic and corrosion resistance, shape return with temperature changes, and a high level of biocompatibility. The surgeons' increased interest in this material is explained by their desire to minimize labor and time costs by choosing an adequate fixative in the planned operation.

According to the greatest similarity with the proposed solution, the specified suture material is selected as a prototype.

An important characteristic of the suture material is the handling quality, including the elasticity and plasticity of its deformation, stabilizing the formed seam. The increased elasticity characteristic of titanium nickelide of known suture material is combined with a plasticity deficit, which is a drawback for this characteristic.

The technical result of the invention is to increase the handling quality of suture material.

The specified technical result is achieved by the fact that in the structure of the suture material containing the thread (s) of superelastic titanium nickelide, additionally included (s) thread (s) of plastic titanium nickelide, and the diameters of the threads of the material are selected from the range of 30-60 μm.

The manipulative quality of suture material is determined by the convenience for the operator to perform the necessary actions when bonding disparate tissues. The suture material thread should be, preferably, soft to the touch, malleable in traction actions, shape-preserving in the formed seam and knotted knot.

The task of improving the handling quality of suture material in this proposal is solved by adding a plastic component to the composition with an elastic component of the prototype. The attainability of the technical result is most evident in the graphical representation of the deformation characteristics of materials.

In FIG. Figure 1 shows the dependences of the strain stress of individual components and their composition on the strain value. Curve 1 describes the elastic deformation during loading of the sample (section of the OAW) and reactive return to the initial state (section of the GDO). The last section on the segment SM is used as a worker for fixing stitched fabrics.

, почти полной остаточной деформацией (участок СО, фиг. 2), в силу чего такой материал логично назвать сверхпластичным.The phenomenon of elasticity (“the effect of superelasticity” with respect to intermetallic compounds) is due to the regularity of atomic growths in the crystal lattice of the alloy upon deformation of the object (martensitic transformations). Given a change in the technological parameters of the alloy (the composition of the initial charge, the temperature of the melting), you can control the degree of reversible (unloading) deformation, without bringing the restoration of the crystalline structure to its original state. The residual deformation in the sample of such an alloy (section CO, curve 2, Fig. 2) is depicted by a zero voltage value. In contrast to the fully returnable “elastic” deformation of sample 1, such an alloy is characterized by a low level of critical martensitic shear stresses

, almost complete residual deformation (section CO, Fig. 2), which is why it is logical to call such a material superplastic.

The composition of both materials in bifilament performance leads to a combination of the properties of elasticity and plasticity, which, subject to the conditions of distinctive features of the proposed device, provides it with the function of a suture material with increased handling quality.

The number and ratio of the number of threads involved in the multifilament use of suture material varies in terms of feasibility in terms of strength and total transverse size.

A limited range of diameters of the threads used, guaranteeing the operability and attainability of the technical result, is justified by the technological capabilities of manufacturing the thread - at the lower boundary, and the lack of consumer need - further than the upper boundary.

The identified signs in their causal connection with the technical result do not seem obvious to the conditional specialist in this field of technology, which indicates that the proposed solution meets the criterion of "inventive step".

The illustrations show:

- величина предельно допустимой эластичной деформации;

- значение критического напряжения деформации;

.FIG. 1. The deformation characteristic of superelastic titanium nickelide.

- the value of the maximum permissible elastic deformation;

- the value of the critical strain stress;

.

.FIG. 2. The deformation characteristic of ductile titanium nickelide. Section CO (permanent deformation) characterizes the ductility of the specified material

.

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FIG. 3. The deformation characteristic of the composition of superelastic and ductile titanium nickelide. Residual deformation (OM segment) at

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Checking the functionality of the proposed suture material and proving the attainability of the technical result was carried out experimentally by instrumental measurements on specific titanium nickelide alloys.

Example

Nickel-titanium filaments 40 microns thick of elastic and ductile alloys and their bifilament composition were subjected to tensometric measurements of tensile strain. The latter is formed by the spiral plexus of both threads with a spiral pitch extended up to 10 mm.

The measurement results are presented by load-unloading diagrams “strain-stress” in FIG. 1-3.

A superelastic alloy (deformation characteristic of Fig. 1) was obtained by melting a mixture with an ingredient composition: in weight percent - titanium 45, molybdenum - 0.5, iron - 0.1, the rest nickel.

,

,

Quantitative values of the deformation parameters of this alloy:

,

,

A ductile alloy (deformation characteristic of FIG. 2) was obtained by melting a mixture with an ingredient composition in weight percent: titanium - 45, molybdenum - 0.5, iron - 1.5, the rest is nickel.

,

,

.Quantitative values of the deformation characteristics of this alloy:

,

,

.

.The bifilament composition of these alloys is a material combining elastic and plastic properties (Fig. 3). The residual deformation (OM segment) at its maximum value of 6% is 3%,

.

The manipulative properties of the suture material are assessed by the subjective sensations of the surgeon during the stitching of disparate tissues by the ease and convenience of traction of the thread, the formation of sutures and nodes, as well as by the adequacy of the reaction of the material to the postoperative change in stitched tissues. According to the reviews of experienced surgeons at the hospital surgery clinic of the Siberian State Medical University (Tomsk), who used the proposed suture material, its manipulative quality exceeds comparable known analogues.

Clinical experience of use and technological availability indicates compliance of the material with the criterion of the invention "industrial applicability".

Claims (1)

Suture material containing a thread (s) of superelastic titanium nickelide, characterized in that the suture structure additionally includes (s) thread / (s) of an alloy having the following composition, titanium 45%, molybdenum - 0.5%, iron 1.5 %, the rest is nickel, and the diameter of the material strands used is selected from an interval of 30-60 microns.

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