Patent Office 1999,64

Patented Apr. 30, 1935 1999,641 UNITED STATES PATENT OFFICE 1999,64. STRAND FOR, SUTURE AND OTHER PUR POSES AND METHOD OF MAKING THE "SAVE George Aaron Sharp, Los Angeles, Calif., assignor to Davis & Sharp, a corporation of California. No Drawing. Application July 30, 1932, Serial No. 62,25. Renewed October 26, 1934 22 Claims. (C. 128-335,5) This invention relates to sutures, ligatures, tory to employ long coarse tendon fibers, Such as cords and the like, and to methods of manufac those obtained from the tendon fascia, lata, turing the same. derived from the thighs or quarters of steers or It has been common practice to make sutures, beeves. It has been attempted heretofore to 9 Such as are Ordinarily used in surgical work, of make sutures from such tendons, but as far aS Catgut, which is most frequently produced from I am aware, they have never been produced Com sheep intestines. mercially, for a number of good rea,Sons. Such catgut sutures are relatively expensive, It is difficult to obtain twisted Strings or cords because of the expert and laborious hand work from Such tendon material by approved textile 0. required in their manufacture and because of the processes and machinery, and it has been pro O relatively high prices of the sheep intestines posed, but without success, to utilize relatively caused by great demand for other purposes. In less satisfactory braided cords or Strings, the con addition, catgut, while extensively used because stituent fibers of which are caused to adhere to of the absence of something better, is not entire gether by glue or other adhesive; or to form the ly Satisfactory, due to the difficulty of obtaining material into thin sheets, by Overlapping and 5 catgut Sutures of uniform size, of sufficient pressure, which sheets were to be slit into rib Strength and flexibility to permit most efficiently bons. Sutures prepared of a plurality of braided of the Stitching and tying necessitated in surgical fibers glued together have been Suggested for Work, and because of the difficulty of rendering surgical work, but did not prove satisfactory be 20 then sterile and capable of being treated at ade cause they do not remain homogeneous in the 20 site Sterilizing temperatures without deteriora tissues. The lytic substance such as the lymph O in the tissues will dissolve the adhesive, with the Intestinal tissues, forming the basis of catgut, result that within a relatively short time the con are porous and are almost always infected and stituent fibers will fall apart, permitting the Su 2 5 contaminated with harmful pathogenic bacteria, tures to disintegrate. 25 particularly of tetanus or lockjaw variety, and in Among the particular objects of the present many cases of the anthrax type. These bacteria invention are, therefore, to prepare substan withstand relatively high sterilizing tempera tially pure collagen Sutures from the fibers of tures. Sheep catgut also usually contains fats, animal tendons, which may be readily spun or 30 mucosa, irritating fatty acids and other impuri twisted into a cord, strand, Suture or ligature 30 ties, which are not altogether eliminated by the by approved textile processes, and which may be many purifying and scraping operations to which formed into a homogeneous and unitary cord , the catgut is subjected. These last-mentioned or string without an added adhesive and of such inpurities cause the catgut to become harsh and structure as to withstand the action of tissue brittle, and to decrease in strength and flexibility, solvents and sterilizing temperatures without any 35 particularly when it is subjected to sterilizing substantial disintegration or impairment. temperatures. In One embodiment of my invention, the pure Among the objects of the present invention are White connective tissues contained in the leg to provide sutures which will be free from these tendons of year-old veal, or calves, or of sheep, 4) defects, which may be easily and readily manu and preferably the tendo Achillis derived from 40 factured from inexpensive raw materials, and by the hind legs of Such calves or veals are utilized, automatic machinery of the type usually em as preferred tendon materials. ployed in the textile industries; which will be AS a Specific example of one method of pre normally, sterile or which may be readily sterilized paring the Sutures of the present invention, the at high temperatures without substantial deteri following is given: The muscular, fatty and other 45 oration, which will have sufficient strength and tissues adhering to these tendons are removed, flexibility to be efficiently and facilely stitched and the tendons are then dried. These tendons and tied in Surgical operations, even after treat are usually about 2 to 2% inches long, and as ment or effective sterilizing temperatures, and slender as perhaps One-eighth of an inch, With 50 Which may be made of controlled and uniform about 300 of them producing one pound of fiber, 50 Sizes for any desired purpose. 30,000 tendons being approximately equivalent In accomplishing these objects it has been to a one hundred pound run of fiber. found satisfactory to employ animal tendons. In After drying the tendons, they are run through preparing sutures from animal tendons experi a machine, which will crack off the capsule or 55 ments have demonstrated that it is not satisfac tendon sheath, and also open up the interior fiber 55 2 1999,641. structure so that the shredder teeth can get in sutures. Sutures are customarily cut into 5 foot between them and tear the fibers apart. lengths and put into glass tubes, the surgeons The shredder, which is next emplgoyed, will later cutting them into shorter lengths as re Separate the fibers so as to prepare them for quired. The cord is also wound on the drums so carding. In the carding machine the material is that no two laps of the cord will touch one an 5 carded and combed down to very fine fibers and other, which permits of perfect processing and thereafter is passed into a roving machine, which prevents adhesion between the different laps of forms the fibers into a very small roving, so cord. The drum with the cord wound upon it delicate that it is just able to hold together. now is put into a substantially constructed vac O These rovings are passed into a spinning ma uum chamber, and there every vestige of moisture 0 chine, from which they are obtained in the form is extracted under high vacuum and at a tempera of fine yarn, and this yarn is passed into a twist ture of about 52 C., for a period of about 75 ing machine which takes several strands of minutes. the yarn and twists them into what is, after At the completion of the seventy-five minute 5 further treatment, to become the final substan drying period, a caustic solution, preferably of tially transparent or glossy cord of very attrac the same temperature as the inside of the vac tive appearance and external smoothness. uum chamber, is passed into the vacuum cham These spun cords or strands thus formed are ber to Submerge the drum. With the cord there then treated with carbon tetrachloride or with upon. A Satisfactory caustic or alkaline Solution 20 Some other Suitable fat solvent in a Soxhlette for this purpose may consist of a 0.235% sodium 20 apparatus. The fibers are also subjected to the carbonate solution in distilled water. Selective digestive action of enzymes, such as After addition of the caustic solution the same lipase and trypsin which will dissolve out or re high vacuum is reestablished, but the tempera move the other impurities from the animal ma ture is gradually allowed to decline to 45° C., and 25 terials namely, the mucin and elastin with the this temperature is maintained for eighteen 2 5 ultimate object of producing fibers of pure col hours. lagen. The Selective enzymes are present in an After eighteen hours the drum with the strand alkaline bath or baths and have a selective diges thereoni is removed from the vacuum chamber tive action on the fat, mucin and elastin present and for several hours is subjected to a Washing 30 in the fibers, but do not have any digestive ac operation in running distilled water. The drum 30 tion on the collagen. The cords or strands or and strand next is placed in a bath of hydro their fibers are allowed to remain in the bath chloric acid solution for neutralizing the caustic, or baths for a sufficient time to properly digest and then it is placed in a weak solution of Sodium the impurities mentioned. By removing the non carbonate to neutralize' any acid. Then it is 35 essential impurities, namely, the elastin, mucin again washed in running water, and this time and fats, which is accomplished by the selective for about twelve hours. digestive enzyme step or steps of the method, After this washing operation the drum of cord the bulk or size of the cord or strand is reduced is air dried for about twenty-four hours in a and elasticity properties are greatly improved. normal atmosphere, and after that is dried in a 40 To neutralize any fatty acids which may be pres vacuum chamber under a relatively high vacuum 40 ent in the fibers at this stage, a neutralizing at 52 C. agent, or an alkali, such as sodium carbonate, The thoroughly dried cord is then subjected may be employed. After these solvent treatments, to a treatment of formalin to coagulate or harden the cords or strands are washed in distilled it and to render it more slowly absorbed in the 45 running water for about three hours to remove tissues for definitely predetermined lengths of from their fibers all traces of the treating chem time, such as 10 days, 20 days, 30 days, etc., as icals and other objectionable substances.

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