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Surgical Needle Patent
 

Siliconized surgical needle and method for its manufacture

Surgical needle abstract

A siliconized surgical needle is provided which requires significantly less force to effect tissue penetration than a standard siliconized needle.

Surgical needle claims

What is claimed is:

1. A method for manufacturing a siliconized surgical needle comprising

a) providing a surgical needle possessing a suture top receiving axial recess in its blunt end;

b) placing the needle in a ultrasonic cleaning unit having a vapor section;

c) moving the needle to the vapor section of the unit;

d) removing the needle from the ultrasonic cleaning unit;

e) applying a curable siliconization material upon the needle while its recess is unoccluded, there being no significant amount of the siliconization material entering the bore;

f) allowing the siliconization material to spread evenly over the needle's surface; and

g) curing the siliconization material on the needle to provide a silicone coating thereon.

2. The method of claim 1 wherein applying is selected from the group of wiping and spraying.

3. The siliconized surgical needle of claim 2 wherein the silicone coating on the needle is obtained from a siliconization material comprising an aminoalkyl siloxane, a cyclosiloxane and at least a hydrocarbon solvent selected from the group consisting of hexane and heptane.

4. The method of claim 1 wherein the shank end of the needle is embedded in a support material during the applying step.

5. The method of claim 1 wherein the siliconization material comprises an aminoalkyl siloxane and at least one other siloxane.

6. The siliconized surgical needle of claim 5 wherein the silicone coating on the needle is obtained from a siliconization material comprising an aminoalkyl siloxane, at least one other siloxane copolymerizable therewith and at least on hydrocarbon solvent of from 5 to 10 carbon atoms.

7. The method according to claim 5 wherein the needle after siliconization exhibits less than about a 100% increase in penetration force after about 5 successive passes through a microporous polyurethane membrane about 0.042 inches thick.

8. The method of claim 7 exhibiting less than about a 77% increase in penetration force after about 5 successive passes through a microporous polyurethane membrane about 0.042 inches thick.

9. The siliconized surgical needle of claim 7 exhibiting an average tissue penetration force after 10 successive passages of less than about 500 grams.

10. The siliconized surgical needle of claim 9 wherein the uncoated needle possesses a diameter of about 0.039 inches.

11. The siliconized surgical needle of claim 7 wherein the needle is fabricated from an alloy comprising nickel, cobalt, chromium and at least one metal selected from the group consisting of molybdenum, tungsten and niobium.

12. The siliconized surgical needle of claim 11 wherein the needle is fabricated form (sic) an alloy comprising from about 10 to about 50 weight percent nickel, from about 10 to about 50 weight percent cobalt with the combined weight of nickel and cobalt being from about 50 to about 85 weight percent, from about 10 to about 30 weight percent chromium and from about 5 to about 20 weight percent of at least one metal selected from the group consisting of molybdenum, tungsten and niobium.

13. The method of claim 7 wherein the silicone coating on the needle is obtained from an aminoalkyl siloxane and an alkyl polysiloxane.

14. The method of claim 7 wherein the silicone coating on the needle is obtained from an aminoalkyl siloxane and a cyclosiloxane.

15. The method of claim 5 wherein the needle exhibits less than about a 200% increase in penetration force after about 10 successive passes through a microporous polyurethane membrane about 0.042 inches thick.

16. The method of claim 15 wherein the needle after siliconization exhibits less than about a 150% increase in penetration force after about 10 successive passes through a microporous polyurethane membrane about 0.042 inches thick.

17. A method for manufacturing a siliconized surgical needle possessing a shank of reduced diameter which comprises embedding the shank in a support material, spraying a curable siliconization material upon the exposed surfaced of the needle and thereafter curing the siliconization material on the needle to provide a silicon coating thereon.

18. The method of claim 17 wherein the siliconization material comprises an aminoalkyl siloxane and at least one other siloxane.

19. The method of claim 18 wherein the silicone coating on the needle is obtained from a siliconization material comprising an aminoalkyl siloxane and a cyclosiloxane.

20. The method of claim 18 wherein the silicone coating on the needle is obtained from a siliconization material comprising an aminoalkyl siloxane, at least one other siloxane copolymerizable therewith and at least one hydrocarbon solvent of from 5 to 10 carbon atoms.

21. The method of claim 20 wherein the silicone coating on the needle is obtained from a siliconization material comprising an aminoalkyl siloxane, a cyclosiloxane and at least one hydrocarbon solvent selected from the group consisting of hexane and heptane.

22. The method of claim 17 wherein the needle is fabricated from an alloy comprising nickel, cobalt, chromium and at least one material selected from the group consisting of molybdenum, tungsten and niobium.

23. The method of claim 17 wherein the needle is fabricated from an alloy comprising

from about 10 to about 50 weight percent nickel,

from about 10 to about 50 weight percent cobalt with the combined weight of nickel and cobalt being from about 50 to about 85 weight percent,

from about 10 to about 30 weight percent chromium, and

from about 5 to about 20 weight percent of at least one metal selected from the group consisting of molybdenum, tungsten and niobium.

Surgical needle description

BACKGROUND OF THE INVENTION

This invention relates to a surgical needle possessing a silicone resin coating providing reduced tissue penetration force and to a method for manufacturing the needle.

The siliconization of metallic cutting edges of such articles as razor blades, hypodermic needles, scissors, scalpels and currettes has been known for some time.

U.S. Pat. No. 3574673 discloses the silicone coating of a cutting edge employing a siliconization fluid containing a mixture of copolymerizable silicones made up of an aminoalkyl siloxane, specifically a (polyaminoalkyl) alkoxysilane, and a dimethylpolysiloxane.

Dow Corning Corporation's Bulletin 51-599A (July 1986) describes Dow Corning.RTM. MDX4-4159 Fluid for siliconizing cutting edges such as those previously mentioned with an ambient temperature and humidity-curable mixture of aminoalkyl siloxane and a cyclosiloxane dissolved in a mixture of Stoddard solvent and isopropyl alcohol. It is recommended that the fluid be applied by dipping, wiping, spraying, etc., in the form of a dilute organic solution, 2 e.g., prepared with a solvent such as hexane, trichlorotrifluoroethane, 111-trichloroethane or mineral spirits.

U.S. Pat. No. 4720521 describes a film-forming siloxane composition for application to the aforementioned cutting edge articles which contains a mixture of three reactive siloxanes together with a non-reactive lubricating siloxane polymer.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a siliconized surgical needle and method for siliconizing a surgical needle in which the needle exhibits an average tissue penetration force below that of a standard siliconized surgical needle.

It is a particular object of the invention to provide a surgical needle with an adherent silicone coating derived from a siliconization material comprising an aminoalkyl siloxane and at least one other siloxane such as a cyclosiloxane which is copolymerizable therewith.

It is another particular object of the invention to provide a siliconization method to be carried out upon a surgical needle possessing an axial bore, or recess, for receiving the tip of a suture, the siliconization method omitting the step of occluding the bore with water as a preliminary to the application of the siliconization material to the needle.

In keeping with these and other objects of the invention, there is provided a siliconized surgical needle exhibiting an average tissue penetration force which is less than the average tissue penetration force of a standard siliconized needle.

A siliconized needle in accordance with this invention can be obtained by applying to a surface of the needle a siliconization material comprising an aminoalkyl siloxane and at least one other silicone copolymerizable therewith and thereafter curing the siliconization material to provide an adherent silicone coating on the needle.

The expression "standard siliconized surgical needle" as used herein refers to a commercially available siliconized surgical needle, e.g., the siliconized surgical needles marketed by Ethicon, Inc., Somerville, N.J.

While the amount of force required to achieve penetration of tissue during suturing may initially be about the same for both the siliconized surgical needle of this invention and a standard siliconized surgical needle and while both needles will tend to experience an increase in penetration force with each successive passage through tissue, at the conclusion of any given number of such passages, the needle of this invention will exhibit significantly less penetration force than the standard needle. Stated another way, the siliconized needle of this invention will retain its initial tissue penetration characteristics to a greater extent than a standard siliconized needle. This reduced tissue penetration force is advantageous inasmuch as it reduces the effort required in the suturing operation, a particular benefit in those cases involving extensive wound closure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The surgical needles which can be siliconized in accordance with this invention can be manufactured from a variety of metals such as Series 400 and Series 300 stainless steels. Other suitable metals for the fabrication of surgical needles include the quaternary alloys disclosed in U.S. Pat. Nos. 3767385 and 3816920 the contents of which are incorporated by reference herein. A particularly preferred quaternary alloy possesses the ranges of components set forth in Table I as follows:

TABLE I ______________________________________ COMPOSITION OF SURGICAL NEEDLE QUATERNARY ALLOY (WT. %) Broad Preferred Most Preferred Component Range Range Range ______________________________________ Nickel 10-50 24-45 30-40 Cobalt 10-50 25-45 30-40 Nickel + Cobalt 50-85 60-80 65-75 Chromium 10-30 12-24 15-22 Molybdenum, 5-20 8-16 10-13 tungsten and/or niobium (columbium) ______________________________________

A particular quaternary alloy within Table I which can be utilized for the siliconized needle of this invention, designated MP35N, is available in wire form from Maryland Specialty Wire, Inc., Cockeysville, Md. and contains (nominal analysis by weight): nickel, 35%; cobalt, 35%; chromium, 20% and molybdenum, 10%.

The siliconization material employed herein and the procedure used in its application will be such as to provide a siliconized surgical needle exhibiting a significantly reduced tissue penetration force compared with that of a standard surgical needle after an equivalent number of passages through the same, or substantially the same, tissue. Advantageously, the average tissue penetration force of the siliconized needle herein will be less than about 10 percent, preferably less than about 20 percent and still more preferably less than about 30 percent, of the average tissue penetration force of a standard siliconized needle after from 5 to 20 passes through the same or similar tissue.

In general, application of a curable siliconization material containing an aminoalkyl siloxane and at least one other copolymerizable siloxane, e.g., an alkyl polysiloxane or a cyclosiloxane, to a surgical needle followed by curing will provide a siliconized-surgical needle meeting the requirements of this invention.

One suitable method for achieving siliconization herein utilizes the siliconization material and procedures described in U.S. Pat. No. 3574673 the contents of which are incorporated by reference herein. The siliconization material includes (a) from about 5-20 weight percent of an aminoalkyl siloxane of the formula ##STR1## in which R is a lower alkyl radical containing no more than about 6 carbon atoms; Y is selected from the group consisting of --OH and --OR' radicals in which R' is an alkyl radical of no more than 3 carbon atoms; Q is selected from the group consisting of hydrogen, --CH.sub.3 and --CH.sub.2 CH.sub.2 NH.sub.2 ; a has a value of 0 or 1 and b has a value of 0 or 1 and the sum of a+b has a value of 0 1 or 2 and (b) from about 80 to 95 weight percent of a methyl substituted siloxane of the formula ##STR2## in which R" is selected from the group consisting of --OH and --CH.sub.3 radicals and c has a value of 1 or 2.

In addition to, or in lieu of, the foregoing second copolymerizable siloxane, one can use one or more cyclosiloxanes, e.g., as described in the "Encyclopedia of Polymer Science and Engineering", Mark et al., eds , 2nd ed., John Wiley & Son (1989), vol. 15 p. 207 et seq., the contents of which are incorporated by reference herein, provided, of course, the total amount of second copolymerizable siloxane(s) is within the aforestated range.

A particularly preferred siliconization material for use herein is Dow Corning Corporation's Dow Corning.RTM. MDX 4-4159 Fluid ("MDX Fluid"), a 50 percent active solution of dimethyl cyclosiloxanes and dimethoxysilyldimethylaminoethylaminopropyl silicone polymer in a mixture of Stoddard solvent (mineral spirits) and isopropyl alcohol. MDX Fluid can be applied to a surface of the cleaned surgical needle by dipping, wiping, spraying, etc., in the form of a dilute organic solution, e.g., prepared with a solvent such as hexane, trichlorotrifluoroethane, 111-trichloroethane or mineral spirits. In general, it is preferred to dilute MDX Fluid (or other siliconization material) in a hydrocarbon solvent possessing from 5 to 10 carbon atoms, e.g., pentane, hexane (which is preferred), heptane, octane, etc. MDX Fluid cures at room temperature to provide an adherent silicone coating.

After evaporation of any diluent or solvent carrier, the siliconization material is cured to the desired degree. The material can be cured by heating for a short time, e.g., 30 minutes at 120.degree. C., or by exposure to ambient temperature and humidity conditions for longer periods of time.

As previously mentioned, where an axially bored surgical needle is concerned, it is preferred to siliconize the needle employing a procedure which does not require the preliminary step of temporarily occluding the bore. Typically, when siliconizing such a needle by dipping or total immersion in the siliconization material, it has been found necessary to occlude the bore with a liquid, e.g., water, which is immiscible with the siliconization material and thus prevents any of such material from entering the bore where it might interfere with proper attachment of the suture. It has been found that the bore-occluding step can be totally omitted by applying the siliconization material to the needle by spraying. Accordingly, spraying is a preferred method of application of the siliconization material at least in the case of a needle possessing an axial bore, or recess.

Spraying is also the preferred method for applying siliconization fluid to a needle possessing a reduced shank end which is intended to be attached to the tip of a suture employing a shrinkable tubular connector as disclosed in commonly assigned copending U.S. patent application Ser. No. 07/413240 filed Sep. 27 1989 the contents of which are incorporated by reference herein. If is preferred in the case of such a needle to insert the needle shank end--first into a support block, e.g., of rigid foam, and thereafter to spray the siliconization fluid onto the exposed surface of the needle. Since the shank end of the needle is embedded in the support block, it will remain free of silicone during the spraying procedure. The use of a support block can, of course, also be employed in the case of the axial recess type needle described above to prevent siliconization material from entering the recess. It is preferable that the coated needle while still in its support block be subjected to curing conditions; if this involves heat, it will, of course, be necessary to select a support block material which can withstand the elevated temperature selected for curing.


System with a surgical needle and a handle
Combined surgical needle-braided suture device
Grindless surgical needle manufacture

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