CS228122B2 - Surgical sewing or aid materials - Google Patents

Description

The invention relates to surgical suture materials and in particular to soft, elastomeric suture materials having knot-handling and knot-binding properties. The suture materials can be prepared from segmental copolymers / esters or other elastomeric polymers.

A number of natural and synthetic materials are currently used as surgical sutures. These materials can be used as single fibers, i. monofilament sutures or many threads, knitted, twisted or other multifilament yarn. Natural materials such as silk, cotton, linen and the like are not themselves suitable for the production of monofilament sutures and are generally used in some of the mini-fluff structures.

Synthetic materials which are extruded in continuous lengths can be used in monofilament form. Common synthetic monofilament sutures include polyethylene terephthalate, polypropylene, polyethylene, and nylon. Surgeons prefer such monofilament sutures in many surgical applications because they are naturally smooth and lack capillary properties with respect to body fluids.

The currently available synthetic suture materials have to a greater or lesser extent a disadvantage in that they suffer from the rigidity inherent in them. In addition to the fact that rigidity makes the material less manageable and usable, the rigidity of the material may adversely affect the ability to bind knots and their safety. Due to the typical inflexibility of the available monofilament sutures, it is caused that much larger sizes of suture material are intertwined or that they have multi-fiber structures with better handling flexibility.

Monofile š ^; The prior art cleaning materials are also characterized by a low degree of elasticity, the most flexible of the above synthetic materials being nylon having a slip elongation of about 1.7% and a viscoelastic elongation of about 8.5 why. The rigidity of these sutures also makes knot binding difficult and less secure. In addition, the inelasticity prevents this suture material from being administered when the newly sutured wound swells, with the result that the suture material covers the wound tissue with a pressure greater than desired and may even cause some tearing, incision, or tissue necrosis.

Problems associated with the use of inelastic suture materials in certain applications are disclosed in U.S. Pat. No. 3,454,011, which proposes the production of a surgical polyurethane based surgical material. Such sutures were highly flexible and exhibited rubber properties and were not generally accepted in medical practice.

The purpose of the invention is to develop a new, soft, flexible, monolithic suture material. This momophilic suture material should have a controlled degree of elasticity to accommodate varying wound conditions. The new suture material should have a diameter of about 0.1 to 1.0 mm and have the desired physical properties. These and other features will become more apparent from the following description.

The essence of the surgical sutures or prosthetic materials based on elastomeric fibers, made, for example, by knitting, according to the invention is that they are made of stretched and oriented elastic fiber of segmented copolyetherester, consisting of repeating ester units of the general formula

O O Π II fO-D-O-C - / - - C4 in which

R is a bivalent residue remaining after removal of carboxyl groups from an aromatic dicarboxylic acid having a molecular weight of up to 300, and

D denotes a bivalent residue remaining after removal of hydroxyl groups from an alkyldiol of molecular weight up to 250, and from ether / ester units of the general formula

O O, '' 1 '1

-t-O-Q-q-c-R-C-O + wherein

G denotes the bivalent residue remaining after removal of the terminal hydroxyl groups from the poly (C 2-10 ^and alkyl® ⁿ oxide / glycol of molecular weight 350 to 6000, and

R is as defined above, wherein the two types of said units are linked by a head-to-tail bond via ester bonds to form a polymer compound of the general formula

0 Op

OD ~ OC - RC-OCR-C wherein _n OJbJ

R, D, and G are as defined above, and is an integer equal to 50 to 90% by weight. based on the total weight of the polymer compound, when a + b is 100, and n is the degree of polymerization to form a fiber-forming polymer.

The monofilament sutures of the invention are characterized by the following combination of physical properties:

The elongation limit is about 2 to 9

Viscoelastic elongation of about 10 to 30% Yong modulus of about 20.69.10 ³ MPa to

13,82.10 «MPa

Tensile strength min. about 27.55.10 ³ MPa

Knot strength min. about 20.69. IQ ³ MPa

The suture materials of the above properties can be prepared by melt-extruding some elastomeric polymers, such as copolyether / eister polymers, to form a continuous strand of fiber, and then drawing the extruded fiber to obtain suture materials of desired properties. Certain copolyether / ester polymers are particularly suitable for use as starting materials for preparing the suture materials of the invention.

The monofilament sutures of the physical properties of the invention are particularly useful in numerous surgical interventions in which a suture material is used to close a wound that may be subject to later swelling or change of position. The combination of the low Young's modulus and significant elongation limits provide the suture material with a considerable degree of controlled elasticity with little effort. As a result, the suture material is capable of adapting to the swelling at the wound site by administration. The relatively high viscoetastic elongation limit and high tensile strength allow the suture material to stretch while knotting, so that the knot is adapted for improved knotting capability and knot safety with a more predictable and stable knot geometry, regardless of knot or tension knot variations.

1 is a stress-elongation curve characteristic of the suture fiber of the present invention; FIG. 2 is a stress-elongation curve comparing the fiber of the present invention to monofilament suture materials of the prior art.

In Fig. 1 and Fig. 2, the elongation in% is applied to both the x-axis and the stress (load) in units of mass to the y-axis. In Fig. 1 the stress curve is plotted, in Fig. 2 it compares the stress curves of different suture materials, the curve 1 corresponding to the material according to the invention, the curve 2 to the polypropylene material and the curve 3 to the nylon material.

The suture materials of the invention are characterized by a combination of physical properties that are unique to the monafile suture materials and that provide the suture materials of the invention with unique and desirable functional properties.

The characteristics of the suture materials according to the invention are determined easily by conventional tests. Giant. 1 illustrates a typical stress-elongation or strain-elongation diagram for the suture materials of the invention. In Fig. 1, the elongation limit E _y is the point at which the permanent deformation of the suture material begins to occur. If the fiber is not stretched to an E _y value, the elastic return is substantially complete. The sieving materials of the invention have an E _y in the range of 2 to 9%.

Young's modulus is a measure of the slope of the stress curve - the elongation above the initial part of the curve originating from the origin. Fig. 1 is drawn as a tangent to the curve at the origin and Young's modulus corresponds to the angle Θ. The slope of the curve and the Young's modulus are a measure of the resistance to elongation in the initial elastic portion of the curve. The suture materials of the invention have a distinct but relatively low modulus of 20.69.10 ³ MPa to 13.82.10 ⁴ MPa, and preferably in the range of 34.51: 10 ³ MPa to 10.3. . 10 ⁴ MPa. The module within the range of the invention provides the correct amount of increasing tension in the suture material when the suture material is drawn to the cut-off point E _y . At lower Young modulus values, the suture material easily extends at very low stress up to the cut-off point E _y, and the benefits of a considerable elongation limit are lost. At higher Young modulus values, the stiffness of the fiber becomes critical and the softness and good control properties decrease.

The portion of the tension-extension curve extending between the limit value E _y and the value E _v in Fig. 1 represents a viscoelastic region in which the suture material undergoes substantial elongation and permanent deformation, with little increase in tension. The viscoelastic elongation E _{in the} suture materials of the invention is controlled in the range of about 10 to 20%. This property of the suture material allows downward suture of the suture material during knot binding to ensure good knot strength.

When the suture material is stretched to an E value _{in the} viscoelastic extension as shown in FIG. 1, the load (tension) increases rapidly. The rapid increase in load imparts a positive touch to the suture material, which in the hands of a trained surgeon is an indication that an E-value _in viscoelastic elongation and maximum knot strength is achieved. The E _y value of the viscoelastic elongation is preferably at least 2.5 times higher than the limit value E _{in the} viscoelastic elongation is the projected viscoelastic region in which it operates to tighten the suture material.

As can be seen from Fig. 1, the load (voltage) from 0 to the E _y value of the viscoelastic elongation is relatively low compared to the ultimate load § _B. The preferred limit load or tensile strength is at least 27.45. 10 ^MP-3 and a load with _the corresponding viscoelastic stretching is less than one third of the limit load, with the result that sutures can easily make nodes with relatively little force and without the risk of inadvertent breakage of the suture material. The knot strength of the suture material is preferably at least 20.69.10 ³ MPa,

The elongation at break E _{B of the} suture materials of the invention is generally in the range of 30 to 100%. Although this property is not critical to the suture material, because the elongation of the suture material during use does not normally exceed the E value _{in the} viscoelastic elongation, it is preferred that the E _B value is at least 1.5 times greater than the E value _{in the} vlioelastic elongation. and breaking the suture material during tightening.

The unique mechanical properties of the suture materials of the invention will be more apparent from FIG. 2, where such suture materials are compared with known nylon and polypropylene suture materials. Representative physical properties of these three suture materials are shown in Table I. Each of these suture materials known in the art has a significantly higher Young's modulus, resulting in a characteristic inflexibility of these materials. Furthermore, none of these suture materials has a significant cut-off value E _y or an extended viscoelastic region that characterizes the suture materials of the invention and imparts the desired properties discussed above.

The mechanical properties of the suture materials of the invention reflected in the relative values of E _y and E _in combination with low Young's modulus and high tensile strength are exceptional in the surgical suture sector and distinguish the monafile suture materials of the invention from all materials known in the art .

Table 1

sewing material properties Sewing material polypropylene nylon according to the invention diameter in mm 0.32 0.33 0.33 tensile strength MPa 40,2.10 ³ 52.0. IQ ³ 44,1.10 ³ Elongation at break,% 32.2 40.1 39.5 Viscoelastic elongation (E _v ),% 9.0 8.5 14.8 Elongation limit,% 1.1 1.7 2.2 Voltage at E _v (S _v ) MPa 25,2.10 ³ 12,9.10 ³ 9,02.10 ³ Young's modulus MPa 29,2.10 ³ 15,2.10 ³ 7,74.10 ³ Mechanical sewing materials Properties 3,763,109, 3,766,146 a 3,784,520

according to the invention, it can be prepared from the segmented copolyether / ester mixture disclosed in U.S. Patent No. 3,023,192, with reference to column 2, line 20 et seq.

The copolyether / esters of the invention are prepared by reacting one or more dicarboxylic acids or their ester-forming derivatives with one or more dihydric polyethers of the general formula

HO (RO) pH (where R stands for one or more bivalent monosubstituted organic residues and p stands for an integer corresponding to a glycol having a molecular weight of about 350 to about 8000) with one or more dihydroxy compounds selected from the group of bisphenols and lower aliphatic glycols

HO (CH ₂ ) _q OH wherein q is from 2 to 10, except that the regulating component is selected such that substantially all repeating units of the polyester contain at least one aromatic ring. The ester obtained is then polymerized.

The preparation of other related segmental thermoplastic copolymers is described in the following additional references, which are incorporated herein because of the problem: U.S. Patent Nos. 3,651,014, the references, said segmental thermoplastic copolymers can be cast in the form of films, sprayed molten to form or extruded molten to form fibers. However, the products obtained from these references are characterized by physical properties undesirable for surgical sutures. In particular, the filaments of the references are rubbery with a high degree of elasticity, as shown by an elongation at elongation of more than 500%. On the other hand, the tensile strengths are very low, usually less than 5.51 MPa. Fibers prepared from copolyether / esters according to these references thus do not have the mechanical properties of the suture materials of the invention and in fact are apparently unsuitable for use as surgical suture materials.

Disadvantages in the prior art references are overcome by the invention in which the fibers extruded from some copolyether / esters are cooled and stretched, with the result that the mechanical properties of the fibers are checked to be within the specific limits that have been found desirable, especially for surgical sewing materials.

Segment copolyether / esters useful in the present invention comprise a plurality of repeating long chains and ether / ester units linked by a head-to-tail system via ester bonds according to the following general formula:

O 0

(OG-OCR-CO) b [ _n OD-0

The long chains of the ether / ester units of the polymer have the general formula:

O O

II II o-G-O-C-R-C (II).

(AND)

G denotes a bivalent residue remaining after removal of terminal hydroxyl groups from a poly (C2-10alkylene oxide) glycol having a molecular weight of 350 to 6000, and

R is as defined above.

Short chain ester units are defined by the general formula in which

O o

II II

Ί ~ Ο- D ~ O - C ~ R-C - in which

D denotes a bivalent residue remaining after removal of hydroxyl groups from an alkyldiol of molecular weight up to 250,

R is as defined above.

In the above formula (I), an integer equal to 50 to 90% by weight is used. based on the total weight of the polymer compound when a + b = 100 and n is the degree of polymerization to form a fiber forming polymer.

The copolyether / esters represented by the general formula I can be extruded molten, cooled and drawn to give the fibers of the physical properties required for the aforementioned suture materials.

The polymer to be extruded is dried at 94-103 ° C in a hot air circulating oven and / or under vacuum to remove any traces of moisture and other volatile materials. The polymer is then. the melt is extruded and cooled with water using a conventional spinning technique for synthetic fibers, the fiber finally being drawn at least about 5x and usually about 7x to 9x to achieve molecular orientation.

The manufacture of fibers useful as surgical sutures from the copolyether / esters of the present invention is illustrated by the following examples, which are intended to illustrate but not limit the invention. The polymers used in these examples are copolyether / esters prepared from 1,4-butanediol, dimethyl phthalate and polytetramethylene ether glycol (molecular weight about 1000). The polymer comprises hard segments of initrapolymerized butyleneiftalate (short chain ester units) and soft segments of polytetramethylene ether terephthalate (long chain ester units) and, as reported in the Journal of Eliacitomers and Plastics 9, 416-438 (October 1977), has the following general formula

O O c

(hard segment) (soft segment) (IV) wherein a and b are as defined above and x is an integer corresponding to the molecular weight of the etherglycol reactant (x = 14 for a molecular weight of about 1000).

In the following examples, the physical properties of the individual monoYoung modulus (MPa) were determined

Θ denotes the angle shown in Fig. 1,

SX denotes the cross-section of the fiber;

The inia stress of the permanent deformation limit (S _y ) denotes the load at the point of intersection of lines a and b drawn tangentially to the initially elastic region and the viscoelastic region of the curve as shown in Figure 1. The elongation limit (E _y ) is the elongation corresponding directly to the stress curve stretching. The viscoelastic stress S _v is the load at the point of intersection of line b with line c drawn tangentially to the curve as shown in Figure 1. The viscoelastic strain E _v is the elongation corresponding to E _v is the elongation corresponding to the multi-elastic stress S _v and is read directly from the curve.

on the Instron tester under the following conditions:

Cross head speed (HX): 12.7 cm / min

Paper speed (CS): 25.4 cm / min

Sample Length (GL): 12.7 cm / min

Scale load (SL): 357.15 g / cm

Referring to Fig. 1, the You-ng modulus is calculated from the slope and the stress strain curve in the initial elastic region, as follows:

_ angle GL x GL x CS x SL_

HX x SX

The elongation at break (E _B ) and the tensile strength at break (S _B ) are read directly from the stress-elongation curve as shown in Figure 1.

Then continues orig. pp. 22–25 including. Examples

Example 1

A sample of a copolyether / ester of formula IV containing about 40% by weight of soft segments and about 51% by weight. tertertaloyl units, 16% units derived from polytotnamethylene ether glycol and 33% units derived from

1,4-buitanediol, was dried for 4 hours at 94 ° C in a circulating hot air oven and then dried under vacuum at 100 microns (without heating) for 16 hours. The dry polymer was placed in a 2.5 cm horizontal extruder and extruded at a extrusion temperature of 195 ° C.

The extrudate was cooled with water at room temperature and drawn to a monoile suture of size 2 to 0 using an 8.8-fold drawing ratio at 277 ° C and a winding speed of 147.8 m / min. The physical properties of the fibers obtained are given in Table II.

Example 2

A sample of a copolyether / ester of formula IV containing about 23% by weight of soft segments and about 45% by weight. terephthaloyl units, 4% ortho-fitaloyl units, 20% units derived from polythiophylene ethylene glycol and 31 units derived from 1,4-butanediol were dried and extruded at 187%! as in Example 1. The extrudate was cooled and drawn to size 2 up to 0 monofilament fiber using a draw ratio

7.5 x at 210 ° C and with a winding speed of 125 m / min. The physical properties of the fiber obtained are given in Table II.

Example 3

A sample of a copolyether / ester of formula IV containing about 18% by weight of soft segments and about 41% by weight. terephthaloyl units, 35% units derived from polytethylether glycol and 24% units derived from

1,4-butanediol was dried and extruded at 190 ° C as described in the example

1. The extrudate was cooled and drawn to a size of 2 to 0 monofilament suture material using a draw ratio of 6.5x at 262 degrees Celsius. The winding speed was 23 m / min. The physical properties of the fibers obtained are given in Table II. Let it be; The Youpg modulus of these fibers has exceeded the maximum desired limit for the suture material of the invention.

Example 4

Three parts of the copolyether / ester of Example 1 and two parts of the copolyether / ester of Example 3 were dry blended to form a polymer having a total of 30.2% soft segments. The mixed material was dried in a vacuum oven for two hours at a pressure of 1-2 mm Hg (without heating), and then heated to 50 ° C for three hours at 1-2 mm Hg.

The dried mixture was melt mixed

1.8 cm Brabender extruder at 63 cm drum 20/01 screw and extruded at a temperature of 188 C, press ^Q 0.39 cm in the vertical production device monofiliních fibers. The extrudate was quenched with water to ambient temperature, peoelitoized and dried again as described above for the dry blended material prior to extrusion into momophilic suture materials. At a temperature of 187 ° C, a 2 to 0 size monoiphile suture material was extruded using a pull ratio of 7.9x at 215 ° C and a winding speed of 132 m / min. The physical properties of the fiber obtained are given in Table II.

Example 5

3.5 parts of the copolyether / ester of Example 1 and 1.5 parts of the copolyether / ester of Example 3 were dry blended to total content.

33.4% of soft segments and extruded according to the general method of Example 4, using a final drawing ratio of 7.5x at a drawing temperature of 252 ° C and a winding speed of 25 m / min to obtain a monofilament suture of size 2 to 0. The physical properties of the fibers obtained are given in Table II.

Example 6

The process of Example 4 was repeated using the various copolyyeine / ester mixtures of Examples 1, 2 and 3 having the composition ratios of the mixture as shown in Table II. The physical properties of the fibers obtained are also given in Table III.

Example 7

The copolyether / ester of Example 1 with 40% soft segments was dried and extruded according to the general procedure of Example 1 using a 5.08 spinnerette. . 10 to ⁴ m, to obtain a suture material of 5 to 0 and using a spinneret

ky cross section 12,70.10 ^-4 m to obtain a size 0 suture drawing conditions and properties of the obtained fyz.kální suture material are compared in Table IV, the suture size 2-0 of the same composition prepared according to the Example 1.

Table II

Examples

2 3 4 5

Size of sewing material 2—0 2—0 2—0 2—0 2—0 Diameter mm 0.28 0.33 0.31 0.34 0.34 Node strength MPa 25.5. 10 ³ 27.3.10 ³ 30.8.10 ³ 27,5.1O ³ 28,1.10 ³ Tensile strength MPa 44,0.10 ³ 48.9.10 ³ 49.6.10 ³ 44.9. 10 ' ³ 41,2.10 ³ Elongation at break% 31.8 27,8 18,3 25.2 31.4 Viscoelastic elongation% 18.6 13.3 7.25 10.33 11.6 Elongation limit% 3.2 2,9 2,6 4.2 4.7 Young's modulus MPa 34,3.10 ³ 11.8.10 ³ 22.0.10 ³ 9.61. 10 ³ 8,24.10 ³ Table III Composition of poles- ratio % wt. Young's module viscoelastic extension The limit of pro- meru% wt. soft MPa at break of elongation talžlení wt. soft složeik segments e ₃ ,% E _v ,% E _y ,% segments 40/23 65/35 34.05 57,4.10 ² 34.8 14.3 9.2 40/18 75/25 34.50 73,3.10 ² 33.4 13.3 3.2 40/23 50/50 31.50 71,8.10 ² 33.7 14.7 1.9 40/18 70/30 33/40 82,3.10 ² 31.4 11.6 4.7 40/18 65/35 32/30 92,2.10 ² 27.5 12.1 4.6 40/18 601/40 31/20 96,0.10 ³ 26.5 10.2 4.8 40/18 55/45 30/10 11,7.10 ³ 24.5 10.8 2.6 40/18/23 30/30/40 26/60 11,8.10 ³ 18.9 10.3 3.5 40/23/18 30/30/40 26/10 13,8.10 ³ 22.4 10.3 2.8

Table IV

Size of sewing material

5—0 2—0 0 Draw ratio 7.5 8.8 7,3 * Temperature, ° C 171, 277 188 Winding speed, m / min 62 146 33 Diameter 10 ^{- 5} m 19.8 28.2 35.6 Node strength, MPa 33,3.10 ³ 25,5.10 ³ 23,5.10 ³ Tensile strength, MPa 46.1. 10 ³ 43,1.10 ³ 47,1.10 ³ Elongation at break,% 43.5 31.8 36.7 Viscoelasit drag and drop,% 10.8 18.6 17.6 Young's modulus, MPa 33,3.10 ³ 34.3. 10 ³ 35.3. 10 ³ * Two-stage dragging Table 1ka V Sewing material sterilized non-sterile control Co ⁶⁰ ethylene oxide Diameter, 10 ^-5 m 31.75 32.0 33.9 Node strength, MPa 24.5 .10 ³ 22,6.10 ³ 20,6.10 ³ Tensile strength, MPa 48,0.10 ³ 48,0.10 ⁶ 47,1.10 ³ Elongation at break,% 28.2 31.6 45.2 Viscoelastic elongation, ° / o 13.2 15.0 23.5 Elongation limit, ° / o 2.9 2.3 2.2 Young's modulus, MPa 12,7.10 ³ 11,4.10 ⁴ 94,1.10 ²

Example 8

The monophilic suture materials prepared from the copolyelther / ester of Example 2 with 23% by weight of soft segments were sterilized by irradiation with cobalt 60 and ethylene oxide, by conventional methods for sterilizing surgical suture materials. The physical properties of the suture materials were influenced by ethylene oxide sterilization with little and even less cobalt 60, as shown in the data in Table V.

Important physical properties of suture materials prepared from copolyether / esters depend on changes in polymer blend composition and manufacturing conditions. For example, viscoelastic elongation and elongation limit increase with increasing proportion of soft segments in the polymer, and Young's modulus decreases with increasing proportion of soft segments. The elongation at break can be reduced and the tensile strength increased by using a higher tensile ratio during the production of the suture material. By controlling the composition and varying its processing conditions, it is possible to obtain a specific mechanical property for the individual suture materials over a wide range.

While the foregoing examples have focused on the production of muonophilic sutures from copolyeither / esters for one reason, one polymer system has been described (and the effect of different polymer blends and spinning conditions on fiber properties. Copolymer / edter polymers can also be used in making The materials and individual fibers and strips can be used in the manufacture of surgical fabrics and woven or knitted prosthetic devices, such as rye and acterial prostheses.

In addition, the elasbomeric fibers having a combination of physical properties according to the invention can be prepared from other polymer systems, for example polyurethane or silicone elastomers. The elastomeric fibers of the invention may be intermixed with other elaotomeric or non-elastomeric fibers and with any absorbable or non-absorbable fibers in order to prepare the yarn 1 a fabric of special properties, all of which are within the scope of the invention.

Claims (1)

Subject Surgical suture or prosthetic materials based on elastomeric fibers, for example made by knitting, characterized in that they are made of stretched and oriented elastic fiber of segmenized copolyether / ester, consisting of repeating ester units of the obeon formula 0 O II ll. - / o-o-o-c-R-c in which i R is a bivalent residue remaining after removal of carboxyl groups from an aromatic dicarboxylic acid having a molecular weight of up to 300, and VYNALEZU D is a bivalent residue remaining after removal of hydroxyl groups from an alkyl diol of molecular weight up to 250, and from either / ester units of formula 0 ° -G-O-C-P-C-O + in which G is a divalent radical remaining after removal of terminal hydroxyl groups from poly (C ₂ _ _{1 (jalkylenioxid)} glycol of molecular weight 350 and 6000 DZA R has the abovementioned meaning, with both types of said units are linked with a head - tail through ester bonds to form a polymeric compound of formula oooo | j oDoc Jafo-RC-G - C ~ OJfa_J _OCR-n in which R, D and G have the meanings given above, and is an integer equal to 50 to 90% by weight. the total weight of the polymer compound when a + b - 100, and n is the degree of polymerization to form a fiber-forming polymer.