FI58872B - SURFACES SURGICAL MULTIFILAMENT SURFACE - Google Patents

Description

R5F * 1 M (11) ANNOUNCEMENT 'flSSfiA l J'; UTLÄGGININOSSKRIFT 300 / z

JertS C (45) Patent granted on 11 May 1931

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HtmM. j »r« klst «Rih» ll) TiM (44) Nihtivtiuip ^,. icu «M» iiutem pvm.- ratnt · odl reglsterstyrelwn 'AmMod utltfd och udjdcrlftm pubtlcand 30.01.8l (32) (33) (31) «weMwiw-e ^ w priori * ·» 03-11-72 USA (US) 303588 Proven-Styrkt (71) Ethicon, Inc., Somerville, New Jersey, USA (72) Alastair Wilson Hunter, Somerville, New Jersey, Darrell Robert Thompson, Somerville, New Jersey, USA. (7M Oy Kolster Ab (5 * 0 Braided multi-strand surgical suture - Tvinnad kirurgisk multifilamentsutur

The present invention relates to surgical sutures and in particular to multi-strand sutures. Several surgeons have used braided polyester multifilament sutures because of their strength both because they do not react with tissues. Other surgeons prefer to use waxed silk when an unabsorbed bandage is needed because it has excellent handling, is easy to tie, and easily passes through tissues.

An important feature of sutures in deep wound surgery is that they allow a simple loop knot to be brought down along the wire into place. This behavioral property, sometimes referred to as the "knot binding property," can be judged subjectively by tying the yarn around a suitable blank. A single loop knot is then formed and, pulling from the two free ends, this knot is forced to slide along the wire. The roughness or evenness of this sliding motion is an important criterion for operation.

Uncoated braided sutures, such as braided polyethylene 2,58872 terephthalate sutures, provide very coarse jerky action while sutures coated with TEFLON material as described in U.S.A. in U.S. Pat. No. 3,527,650 and wax-coated braided silk scarves have a very uniform behavior. The roughness or flatness of this "knot binding" is measurable and can be represented by a numerical value that makes it possible to predict the behavior of the surgeon's treatment without relying on the subjective experiment referred to in the previous paragraph. One method uses an INSTRON general test meter to determine "knot binding properties" and this will be described below.

The present invention is directed to a braided suture having improved knot bonding properties by using a coating composed of a non-toxic and physiologically inert polymer that does not adversely affect the processability or strength properties of the suture.

It has been found that the knotting property of braided twisted or coated multifilament sutures can be improved (reduced roughness) by applying to its surface polyesters derived from the polymerization of lactones or obtained by esterification of low molecular weight glycols with dimeric acid.

The suture according to the invention is characterized in that its surface is coated with 0.5 ~ 5% by weight - based on the suture, of a polyester of the formula - - 00 00 il n n n

H0- (CH 2 -O - C (CH-) m -C-O (CH 2) -O --- C- (CH 2) -C-O- (CH 2 -OH

d n 2 d n 2 m 2 n where n is an integer greater than 1 and less than 13, m is an integer greater than 1 and less than 9 and X is the degree of polymerization, or has the formula ~ Ö 0

11 II

H - 0 (CH2) 5-C-0R0 - C (CH 2) 5-0 - H

X / 2 wherein R is a polymethylene group and X is a degree of polymerization, wherein the polyester has a molecular weight of 1,500 to 5,000.

3,58872 Thus, stoichiometric amounts of succinic acid, glutaric acid, adipic acid, pimellic acid, cork acid, azelaic acid, sebacic acid, or mixtures of these can be condensed with these diolecene, ethylene glycol, propylene glycol, butanediol, polyesters suitable for use as a coating are obtained. Polyesters of the above formula having a molecular weight in the range of approximately 1,500 to 5,000 and characterized by having at least two carbon atoms between the ester bonds in the polymer chain have been found to provide the best lubricating and handling properties over silk and polyester sutures. Particularly preferred polyesters are those derived from 1-butanediol (n = H) and adipic acid (m = U) and having a molecular weight in the range of 2,000 to 3,000.

It is self-evident that branched chain acids, such as -trimethylsuberic acid, have the formula: O CH, CH, O

il,, I 31 3 II

h-o-c- (ch)), - ch -c -c-oh

2 k I

CH 3 3,7-dimethyloctadienoic acid, 1,1'-Cyclohexanecarboxylic acid, mesatonic acid, β, β-dimethylglutaric acid and dimeric acid, and branched chain diols such as, for example, diisononyl glycol, CH,

Ho CH2 - CH - (CH2) 3 - CH - CH2OH

and glycols having a secondary hydroxyl group, such as 1,2-propylene glycol, can be added to the reaction mixture in small amounts as comonomers to produce polyesters suitable as coatings having a melting point above room temperature. The addition of larger amounts of such comonomers to the reaction mixture results in low melting point polyesters which are not suitable for use in the present invention.

Polyesters useful in the preparation of coated sutures in accordance with the present invention may also be prepared by polymerizing lactones. Such polyesters are characterized in that their 58872 k melting point is above room temperature. Particularly preferred is a polyester having a molecular weight of about 2,000 and obtained by polymerizing 6-caprolactones in the presence of polymethylene diol having the formula 0 ~ 0 ~

H - o - (CH2) 5 ~ C - 0 - R - 0 - C - (CH2) 5 - 0 - H

X / 2 X / 2 wherein R is a polymethylene group derived from polymethylene diol and X is a degree of polymerization.

The polyester coating compositions described above are non-toxic and can be applied to a multi-strand suture from solution. The multifilament suture may be braided, twisted or coated in structure. The formation of coated sutures is described in U.S. Patent No. 3,791,388.

The suture is then air dried to remove the solvent to give a continuous coating. The surface coating composition (0.5 to about 5 l based on the weight of the bonding wire) does not adversely affect its breaking strength or stability in any way. Although the lubricating properties are improved by using more than 5% by weight of the binder yarn of the coating composition, it may impair the other physical properties of this suture, especially the stability of the knot.

A numerical value can be assigned to the "knot binding property" in any braided suture when tested according to the experimental setup below. In describing this experiment on "knot binding properties", reference will be made to the accompanying drawings, in which:

Figure 1 is a schematic representation of the INSTRON test apparatus and shows two braided binder wires in place for testing.

Figure 2 is an enlarged perspective view of the single loop node illustrated in Figure 1.

Figure 3 is a copy of the drawing of the oscillographic plotter.

All bonding value measurements shown in the tables below have been performed with a table-top INSTRON tensile tester using a type B traction cell with a full scale measuring range of 100 to 2,000 g. This INSTRON meter is manufactured by Instron Corporation of Canton, Massachusetts USA. In the measurements, a high-speed SANBORN oscilloscope recorder was used to replace the Model 7702A, manufactured by Hewlett-Packard, Waltham, Massachusetts) with a standard 5,88872 INSTRON recorder, which would be too slow to follow the rapid force changes resulting from slippage of the oramellas under test. A high-gain DC amplifier (Hewlett-Packard model 8803A manufactured by Hewlett-Packard, Waltham Division,

Waltham, Massachusetts) to match this plotter with the INSTRON detector and a low voltage DC power supply is connected to tune this detector. Measurements were performed in an air-conditioned laboratory at 22 ° C and 50% relative humidity. A linear squeezing jaw was used to hold the strands of the sampled sutures.

This INSTRON machine is operated at a crosshead speed of 127 cm per minute and the speed of the plotter paper on the oscilloscope plotter is 20 mm per second.

Subjective experiments for "knot binding" comprise the structure 11 of the suture, which is shown in Figure 2 (single loop node). The same shape can be obtained by means of a threading apparatus supported by a steel plate 10, which is shown in Fig. 1. This steel plate is attached to the cross end 12 of this INSTRON tester.

In order to perform "knot bonding" measurements, two strands 8 and 9 of the same suture are attached at one end to a B cell transducer 1U in this INSTRON tester. These sutures are threaded through the hoist arrangement as shown in Figures 1 and 2. One end of the strands is brought together, passed around the wheels 15 and 16 and attached to a single weight 18 which develops a tension similar to that produced in subjective experiments. A weight of 1.1 kg is used in the standard procedure.

Figure 3 shows the traces of the plotter on the braided polyethylene terephthalate suture before and after coating using a polymer to improve the knotting property. The degrees of roughness are measured along the coordinate coordinate and are shown in kilograms throughout the explanatory section and examples (degree of roughness). When comparing relatively smooth samples, the amplitude of the oscilloscope plotter can be increased by a factor of 20.

The present invention may be further illustrated by the following examples, which illustrate preferred embodiments of the invention.

Example I

A condensate polymer is prepared by reacting U2.5% by weight of 1,1 + -butanediol with 57-5% by weight of adipic acid.

6,58872 The polymer thus obtained is a solid, waxy substance having a viscosity of 1Vf5 centipoise at 60 ° C, a molecular weight of 2150, an acid number of 1.7 and a hydroxyl number of 52.1,

The polyester (U, 8i * parts by weight) prepared as described in the previous paragraph is dissolved in 95.16 parts by weight of toluene and this solution is applied to a braided 2/0 polyethylene terephthalate binder strand using a wire finishing spreader "ATLAB" manufactured by Precision Machine & Development Company, P .0. Box 6U5, New Castle, Delaware, U.S.A. Coating is performed under the following conditions:

Wire speed 9 m per minute

Hypodermic syringe size 30 cc

Engine speed 10 rpm

Hysteresis stress 2.3 kg This coated and braided strand is dried in compressed air at a temperature of 21-27 ° C so that the solvent evaporates and is then collected on a collection drum. No curing of the adipic acid ester is required. This coating is continuous over the entire surface of the suture and amounts to 1 weight /? (calculated on the weight of the untreated sewing thread). This coated yarn is sterilized by exposing it to cobalt-60 radiation without a substantial decrease in direct tensile strength or decrease in knot strength.

The physical properties of this braided polyethylene terephthalate binder before and after coating are summarized in Table 1.

Table I

Braided polyethylene- Braided polyethylene terephthalate suture, terephthalate suture, size 2/0 (handle- size 2/0 (coated) void)

Tensile strength 2

As sterile 7020 kp / cm 69I + O kp / cnu

Sterile 6960 pcs / cm 6920 pcs / cm

Knot strength „_

Unsterile 3770 pcs / cm 3750 pcs / cm

Sterile 3650 pcs / cm 3850 pcs / cm

Roughness 1.66 kg 0.1U kg

Similar results are obtained when the polyester resins described in this example are used to coat sutures of braided silk, cotton and collagen. However, larger amounts of τ 58872 solid coating material should be used for hydrophilic substrates such as cotton and silk. Coated sutures made according to this example have excellent knot holding properties.

Example II

A linear polymer of ε-caprolactone, characterized by an average molecular weight of about 2,000 and having the structural formula:

Il II

h o (ch2) 5- c o-r-o c - (ch2) 5 -0 H

__ _ x / 2 I_ _ x / 2 wherein R is a polymethylene group derived from polymethylene diol and X represents the degree of polymerization (manufactured by Union Carbide Corporation,

Chemical Division, 270 Park Avenue, New York City, New York company). This polycaprolactone has a molecular weight of about 2,000 and is sold under the tradename NIAX-P0LY0L D-56O.

The polycaprolactone as defined above was dissolved in toluene to give a 3.8% by weight solution. This solution was applied to a braided strand of polyethylene terephthalate (size 2/0) using an "ATLAB" yarn finishing machine. The coating was performed under the same conditions as described in Example I above and dried in compressed air at 2 ° C. This coated suture is collected on a collection drum after evaporation of the solvent. No curing of polycaprolactone is required. This coating is continuous over the entire surface of the suture and amounts to 1 weight- $ (based on the weight of the untreated suture). The coated suture is sterilized by exposing it to cobalt-60 radiation without any noticeable decrease in direct tensile strength or knot strength. The physical properties of this braided polyethylene terephthalate binder before and after coating are summarized in Table II.

Table II

Braided polyethylene- Braided polyethylene terephthalate suture, terephthalate suture, size 2/0 (handle- size 2/0 (uncoated) ty)

Tensile strength 2

As sterile 67 ^ 0 kp / cm2 6UU0 kp / cm2

Sterile 6660 pcs / cm 6U10 pcs / cm 58872

Table II continues

Braided polyethylene- Braided polyethylene terephthalate suture, terephthalate suture, size 2/0 (handle- size 2/0 (uncoated) ty)

Strength of nodes

Non-sterile 3770 kp / cnn 3620 kp / cnn

As sterile 3Ö30 pcs / cm 3620 pcs / cm

Roughness 1.25 kg 0.30 kg

Similar results are obtained when caprolactone is used to coat sutures (size 2/0 to 6/0) of braided silk, cotton and collagen. The polyesters now used can also be used to coat absorbent synthetic sutures described in U.S. Patents 3,297,033 and 3,636,956, thereby improving knot bonding properties.

Claims (5)

9,58872 1. A braided multi-strand surgical suture with improved knotting property, characterized in that the surface of the suture is coated with 0.5 to 5% by weight, based on the suture, of a polyester having the formula “O 0 0 0 tr n rr tr HO- (CH-) -O - C (CH 2 -C 0 - (CH 2 -O-0- (CH 0) -C-O- (CH 2 -OH 2 n 2 m 2 n 2 m 2 n L _ X where n is an integer greater than 1 and less than 13, m is an integer greater than 1 and less than 9 and X is the degree of polymerization, or has the formula 0 0 tt tr H - 0 (CH2) 5-C -OR0 - C- (CH2) 5-O-H-_X / 2 L -IX / 2 wherein R is a polymethylene group and X is a degree of polymerization, wherein the polyester has a molecular weight of 1,500 to 5,000. Suture according to Claim 1, characterized in that the polyester is a condensate of adipic acid and 1,1-U-butanediol having a molecular weight of 2,000 to 3,000. Suture according to Claim 2, characterized in that the suture consists of silk and the amount of polyester coating is 5% by weight of untreated suture. U suture according to Claim 2, characterized in that the suture consists of polyethylene terephthalate and the amount of polyester coating is 1% by weight of untreated suture. Suture according to claim 1, characterized in that the polyester coating has a molecular weight of about 2,000.