Postgrad Med J: first published as 10.1136/pgmj.25.287.427 on 1 September 1949. Downloaded from 427

THE STORY OF CATGUT By ELDRED J. HOLDER, PH.D., B.PHARM., PH.C.(Edin.)

Historical I656 by Louis XIV, who granted letters patent to The dictionary definition of catgut is 'a tough the Guild whose members supplied racquet cord made from the intestines of animals, es- makers, clockmakers, musicians, cross-bow makers pecially .' There may or may not follow and surgeons. an indication of its uses. A short digression may be permissible to make Mention catgut to a surgeon and he thinks of reference to a natural means of wound closure a suture material; to a musician, he recalls the which has been known for hundreds of years, mellow tones of the or ; to a sportsman namely the use of the mandibles of certain species and he wonders if he remembered to replace the of biting ants. The edges of a wound are brought the press on his tennis racquet. Catgut, to Every- together manually, the ant is held by its body and man, prompts speculation as to its feline origin. allowed to bite across the wound edges; the There is, however, in fact no evidence that the moment it has done so the body is twisted away intestine of the cat has ever been used to produce from the head which, with the jaws, is left acting The name can be traced back to like a modern metal clip. This procedure is still catgut . Protected by copyright. the Arabic cither, an early stringed instrument. used by the aboriginal natives of central Australia The same root is seen in the old name for the and there are records of its use up to recent times dancing master's , a kit. From kitgut to in Greece, Serbia and Algeria. catgut is an easy etymological step. To return to catgut, it was in i868, the year No aid to surgery has had such a chequered before he came to Edinburgh University as career as catgut. It has been in and out of favour, Professor of Clinical Surgery, that Joseph Lister sworn by and sworn at, over a period of some 75 experimentally tied catgut round the right carotid years. Catgut for suturing has been ' going out of artery of a 1l. Thirty days later the animal was fashion' since the writer first took interest in it killed and Lister examined the ligature. At first some I7 years ago. Nevertheless, more is being he thought that it was unchanged, but closer in- manufactured and used today than ever before. vestigation revealed the fact that the catgut was no Why should this be so ? The answer lies in one longer present but had been replaced by a ring of special feature-its absorbability in living animal living tissue. Though Lister is mainly remembered tissues. for his introduction of antisepsis into surgery, his Although this absorbability was not realized recognition of the absorbability of catgut has been http://pmj.bmj.com/ until comparatively recently, the use of animal of fundamental importance in the successful intestine as a ' ' dates back as far as there modern use of this material. are records of mankind. Indeed, it is reasonable to He quickly realized also the risk of introducing assume that its utility would have been recognized infection into wounds by the use of' raw' catgut. long before there was evolved the art of twisting There are records that in I869 he was using an vegetable fibres or hairs into thread. The use of aqueous solution of phenol as a sterilizing agent as a suture is undoubted even so for This would be efficient as a dried intestine catgut. fairly on September 25, 2021 by guest. far back in history as the Papyrus of Ebers, circa sterilizing agent (except for resistant spores) but 3750 B.C. Egyptian surgeons at that time appear would leave the sutures in a waterlogged and to have acquired considerable skill in wound weakened condition. Apparently with the idea repair. of overcoming these defects, Lister then used a Susruta, a Hindu writer who lived about 1500 solution of phenol in olive oil. This would un- B.C., refers to the use of , drawn copper, doubtedly obviate loss of tensile strength but horsehair and animal intestines as ligatures. would be even less efficient in sterilization, though Ferrara, an Italian, at the end of the i6th century the catgut would be 'antiseptic' and far less used intestines of tortoises amongst other suture dangerous than untreated material. He further materials; he seems to have had some precognition anticipated the modern process for 'hardening' of the need for sterilizing because he is said to have catgut, that is for delaying its rate of absorption stored his sutures in wine before use. In France in the tissues, by chromicizing by the use of the importance of catgut makers was recognized in mixtures of phenol and chromic acid solution in C Postgrad Med J: first published as 10.1136/pgmj.25.287.427 on 1 September 1949. Downloaded from 428 POST GRADUATE MEDICAL JOURNAL September I949 which the catgut was steeped for varying the reader is confidently referred to ' Le Catgut' periods. by Dr. A. Fandre (I944). Surgical catgut is not easy to make. The raw material, sheep's intestine, varies from animal to Manufacture animal in quality, width and toughness ; it varies There are two main stages in the production of according to age, to feeding and so on, and cannot a sterile suture; first the manufacture of the be bulked in order to obtain uniformity. In its strand, then its sterilization and preparation for natural state it is loaded with bacteria, both use at operation. pathogenic and non-pathogenic. The problem A cross section of sheep's intestine reveals three lies in its complete sterilization without the main layers; the outer mesenteric coat whereby destruction of the natural properties of the gut. It the intestine is ' slung' within the abdominal is manufactured in this country only under cavity; the middle (sub-mucous and muscular) Government licence, and the conditions and in- layer which is thin, elastic and muscular; and spections required leave no doubt as to the the inner, absorptive mucous layer. bacteriological safety of the final product. Its rate In preparation the gut is split longitudinally into of absorption in the human body is hard to ribbons and by carefully controlled scraping opera- control; the same strand divided into two pieces tions the outer mesenteric and inner mucous coats and implanted in similar locations in two in- are removed. The sub-mucous, muscular rib- dividuals may have different absorption periods bons are twisted, sometimes singly, more often due to idiosyncrasy, sensitivity, vitamin deficiency in twos, threes or fours, then stretched and dried or cachexia. to form an almost solid filament. Thereafter the Many arguments have been used for and against strings must be polished to give uniformity of non-absorbable suture materials. They are often diameter along the strand and a smooth surface, less expensive and more easily sterilized than cat- but not too smooth or the knot may slip after Protected by copyright. gut, they can be of absolutely standard size and suturing with the risk of a disaster such as a tensile strength. If buried, however, they remain 'burst abdomen.' Finally the strands are sorted permanently in the tissues and may at any time into gauges to agree with the size standards in the subsequently become a focus for infection. British Pharmaceutical Codex and the United Two further points regarding non-absorbable States Pharmacopoeia. sutures are worth noting. First, the harshness of Until I944 British manufacturers each had their monofilaments such as -worm gut. Harshness, own catgut size standards with the result that one that is, to the patient, for if the stitches are on the maker's No. I might be equivalent to another surface the cut ends tend to harden and may catch maker's No. 3, and so on. During the recent war, in the dressings; if such materials are used for standards for gauge and tensile strength were buried sutures there is a grave risk of the sharp drawn up and included in the Sixth Supplement, points of the cut ends doing damage to adjacent I944, to the British Pharmaceutical Codex, 1934 tissues, particularly to blood vessels. The other edition. The B.P.C. size standards are nearly point concerns the softer and generally preferable identical with those of the United States Pharma- http://pmj.bmj.com/ braided materials such as braided silk. Even in copoeia which, in addition to reducing confusion interrupted sutures of such materials there is the amongst British makes, was a useful contribution possibility of bacteria finding refuge in their inter- towards international co-operation. stices, whilst in continuous sutures the movement Deliberate hardening to delay the rate of of serum along the suture material by capillary absorption in the tissues is referred to later and is action favours the spread of any incidental in- usually done during manufacture of the raw catgut fection. If, to eliminate this wick-like action, the strings. braided material has been rendered non-capillary, on September 25, 2021 by guest. the disadvantage disappears and gives probably the Sterilization ideal form of non-absorbable suture. A phrase often used by makers and users of The ideal suture material is one which will surgical catgut is ' the catgut problem.' This ex- retain its holding power until healing is complete expression summarizes the difficulty of devising a and will then disappear with a minimum of dis- sterilizing process which is rigorous enough to kill turbance to the tissues. Until a substitute is the most resistant sporing organisms without also found, either natural or synthetic, which has damaging the tensile strength of the strand. superior physical qualities as well as absorbability, What is the bacteriological flora of unsterilized catgut is likely to remain the most popular and catgut ? Primarily it is that of the contents of the valuable of all suture and ligature materials. intestine in the living animal. The non-sporing For a detailed and comprehensive history of organisms, staphylococci, streptococci, B. coli, etc., sutures, and especially of catgut, through the ages, may be disregarded. Whatever their pathological Postgrad Med J: first published as 10.1136/pgmj.25.287.427 on 1 September 1949. 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In vivo digestion test Thick, plain catgut stitches seven days after operation showing accumula- tion of detritus. Postgrad Med J: first published as 10.1136/pgmj.25.287.427 on 1 September 1949. Downloaded from 430 POST GRADUATE MEDICAL JOURNAI. Septembet I949

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Bacteriolokical testine of catout The illustration shows a muscle-broth medium with paraffin seal for aerobic/anaerobic test. September I949 HOLDER : The Story of Catgut 431 Postgrad Med J: first published as 10.1136/pgmj.25.287.427 on 1 September 1949. Downloaded from significance in human ailments, they are com- (phenol, mercury compounds, essential oils); paratively easy to kill in catgut. Even if they sur- causticity (phenol); inhibition, giving an apparent vived other processes of manufacture, the alcoholic but false sterility (mercury compounds); damage fluid normally present in the sealed tube contain- to the catgut (silver salts; iodine: acidity and ing the finished suture would kill all but sporing water-logging; hot oil or alcohol: 'cooking' of organisms. the gut); unintentional increase in resistance to Spores are normally not killed by alcohol absorption (iodine and formaldehyde). (Williams, I936) which to them is merely another Under the Therapeutic Substances Act, I93 I, kind of anhydrous state, and it is precisely for such and subsequent regulations, manufacturers offer- a condition that the dormant spore stage is ing sterile surgical catgut for sale must be licensed designed. This point may still not be fully by the Ministry of Health or by the Department of appreciated as is apparent from the continued Health for Scotland. By the terms of the licence, popularity of rinsing with alcohol or ether as a the authorities must approve the premises in means of' sterilizing' hypodermic syringes. which sterilization is performed, the qualifications Theoretically, if the faecal and pre-faecal con- of the technical personnel and the processes used, tents of the intestine could be entirely removed at whilst samples from every batch sterilized must be the moment of death, the gut should be sterile. submitted to approved bacteriological test before In practical slaughterhouse conditions this is im- the remainder may be sold. possible as is shown by cultures obtained from raw A fundamental difficulty in sterilizing catgut is catgut strings. Both anaerobic and aerobic spores that the contaminating spores are not all on the may be present, the most spectacular and alarming surface of the strand. It will be remembered that being Clostridium tetani. in manufacturing raw catgut strings, ribbons of The presence of tetanus bacilli in bowel con- gut are twisted to form the strand. Spores present tents has been demonstrated often enough. Yet on the surface of the ribbons are sealed

thereby Protected by copyright. thousands of samples of raw catgut strings can be into the interior of the string. The sterilizing tested without finding it. Moreover, in many agent, whether chemical or heat, must therefore years of experience the writer has yet to find a case reach and destroy the resistant spore envelopes of tetanus in which imperfectly sterilized catgut without damaging the sensitive collagen of the could reasonably be blamed as the source of the catgut through which it must first pass. infection. Nevertheless, the wise manufacturer Chemical sterilization is practicable under care- treats every strand as though it were loaded with fully controlled conditions, iodine sterilization the most resistant spores known. having been employed for many years to give Other pathogenic anaerobes such as Cl. welchii, sterile catgut of excellent tensile strength and CI. sporogenes and C1. oedematis maligni are com- pliability. A serious objection to this method is monly present in unsterilized catgut. that it is uneconomical, taking many weeks from The sporing aerobes, which are mostly non- start to finish and requiring much space and con- pathogenic, include in addition to varieties of stant supervision to obtain optimum results. B. subtilis, B. mesentericus ruber which is sometimes Another objection is that although no uncombined called the ' catgut bacillus,' being very common iodine need be left in the catgut, a change takes http://pmj.bmj.com/ and giving, in broth culture, a distinctive off-white place in its chemical constitution which greatly pellicle with a red line running through it. From prolongs the period required for absorption by the experimental work it has been found that aerobic tissues (Holder, I946). Although this was less spores are more resistant than those of anaerobes. serious than having the sutures absorbed too In control bacteriological tests on sterile catgut it quickly, it was not uncommon to find fragments of is, however, necessary to test both aerobically and catgut stitches expelled to the surface of a wound anaerobically. weeks after healing had taken place. From the end of the last century when Lister, Heat sterilization has now largely replaced the on September 25, 2021 by guest. who first demonstrated the absorbability of catgut, chemical method. It has the great advantage of sterilized his sutures by immersion in a strong being a quick process which has little effect upon phenol solution, until catgut offered for sale as the absorption rate of the product and it has been sterile came within the purview of the Therapeutic improved to a stage which gives sterile catgut of Substances Act, many methods of 'sterilization' excellent tensile strength and pliability. used were as unreliable as they were numerous. Normally holding 15 to 20 per cent. of moisture, They included the use of phenol, mercury com- the catgut must be dried before a high temperature pounds, essential oils, peroxide of hydrogen, is applied otherwise the water present in it would iodine, silver salts, formaldehyde and heating in cause ' cooking' or partial hydrolysis with almost oil or alcohol (Holder, I939). complete loss of tensile strength. The sterilizing The main faults included failure to kill spores temperature is critical, less than 1500 C. being in- Dl 432 POST GRADUATE MEDICAL JOURNAL September 1949 Postgrad Med J: first published as 10.1136/pgmj.25.287.427 on 1 September 1949. Downloaded from sufficient for consistent sterility and more than in muscle. Samples of hardened catgut, inserted I55° C. tending to cause brittleness. The heat must through the gastric wall in rabbits and being in be applied evenly throughout the strand and for contact with the stomach contents, were absorbed this reason hot air, which has a low heat con- in less than four days (Holder, '946). Although ductivity factor, cannot be used for sterilizing. wounds of the stomach wall heal with great The customary procedure is for the catgut to be rapidity, these experiments suggest that an coiled, placed in tubes open at one end, dried in absorbable suture may be contra-indicated where ovens at a moderate temperature and then im- the stitches come into contact with the gastricjuice. mersed for sterilization in a heated inert anhydrous It is customary for much of the catgut used in fluid wherein the required temperature and time suturing to be hardened to prolong its absorption of exposure can be closely controlled. period. This is commonly achieved by the action The tubes of catgut are usually processed in of chrome salts, preferably in the ribbon stage of suitable basket containers from which the oil can manufacture. Catgut containing the equivalent of be drained after sterilization and, maintaining approximately one-half per cent. Cr2O, lasts for strictly aseptic conditions, a sterilized alcoholic re- 20 to 30 days in normal muscle and for five to ten conditioning fluid, containing a predetermined days in intestinal tissue. More resistant catgut proportion of water, is introduced and the open may be obtained containing up to I per cent. end of each tube is at once hermetically sealed. Cr203. Samples are taken from each batch.of sealed Manufacturers usually control the absorption tubes, some for bacteriological and some for rate of their catgut by routine in vitro tests. These physical tests, which must be passed before the may take the form of hydrolysis time-checks in hot remainder of the batch is released for sale. aqueous solutions or of enzyme digestion-periods ' Multiple'"packings for sterile sutures, from of catgut strands under tension, using pepsin or which successive be withdrawn portions may for better an alkaline-acting enzyme such as papain orProtected by copyright. use on different occasions, are being discarded on trypsin. The ideal control is the implanting of safety grounds. With the sealed glass tube pack- catgut into living animal tissue (Holder, 1946). ing, any portion of the suture material not required This may be performed by closing an incision in on the occasion for which the tube was opened the dorso-lumbar muscle of rabbits with in- should be thrown away, not kept for use later terrupted stitches and observing, at re-operation at with the consequent risk of contamination. a later date, the breaking strain of the stitches with In order to clean the outsides of the sealed tubes the aid of an accurate spring balance. before opening in the theatre, they may be washed The loss of strength of catgut stitches by in soapy water and stored in jars of antiseptic digestion, when plotted against time, gives a solution. Tubes which can be boiled or placed in straight-line graph so that the date after which in the sterilizer with the instruments before effective holding power (which may be regarded as operation are obtainable, but most makers do not 450 gm. or I lb.) would be lost can be calculated. recommend this 'boilable' pack. In order to Generally speaking, it is safer to have catgut resist avoid damage to the catgut during boiling or absorption for too long rather than for too short a steam sterilizing the storage fluid in the tubes must time. http://pmj.bmj.com/ be completely anhydrous; catgut taken from such It is often recommended that only plain catgut tubes is therefore brittle and wiry and its correct should be used in subcutaneous or fatty tissue. reconditioning in weak alcohol or physiological This, however, leads to another interesting point, saline is a difficult procedure to control in the namely the reaction of the tissues to the intro- operating theatre. duction of catgut stitches. The significant factors are:-the more truly ' plain' the catgut and the Absorption thicker the strand, the greater is the local reaction on September 25, 2021 by guest. The rate of absorption of catgut in the body is (Jenkins, I942). usually determined in normal muscle such as the The first reaction in the tissues after implanting rectus abdominis. catgut is a concentration of polymorphonuclear Catgut which has not been specially treated to leucocytes. If the catgut is quite unhardened, prolong its resistance to digestion lasts from 7 to digestion proceeds at such a pace that there is soon 15 days in normal muscle; such catgut is known as a marked collection of detritus, formed largely of 'plain.' In practice the, process of manufacture disintegrated leucocytes. If the catgut is more of raw catgut strings tends to harden them a little resistant than the plain variety, little or no detritus and most commercial 'plain' catgut lasts from is observable and digestion proceeds mainly by the 14 to 2z days in normal muscle. ingrowth of giant-cells. Such reaction as takes When used to suture the bowel, catgut usually place is greater with a thick suture than with a lasts only one-third to one-quarter of its duration fine one, particularly with plain catgut. September 1949 LE QUESNE : Hind-Quarter Amputation 433 Postgrad Med J: first published as 10.1136/pgmj.25.287.427 on 1 September 1949. Downloaded from A tendency to use thick catgut at operation is ments in the manufacture of surgical catgut over due to an unfounded fear that fine stitches may be recent years resulting in greater tensile strength, insufficiently strong to hold the wound edges in there is no justification on this score for using the apposition, Great force is not normally necessary thicker sizes. to keep a wound closed and even if considerable strain is expected, as in retching or coughing after Conclusion laparotomy, it is more likely that the sutures would To summarize the points covered in this general cut out of the tissues than that the stitches them- survey of catgut as a suture material : selves would break., I. The fundamental advantage of catgut is its The shearing strain of tissues, which is absorbability. analogous to their resistance to the cutting out of 2. It has excellent tensile strength. stitches, is not so high as appears to be generally 3. Sterility, as taken from the sealed tubes, is believed, varying from less than I lb. in soft assured. tissue, as for instance bowel, to no more than 24 4. A hardened or 'chromed,' catgut is pre- lb. in rectus muscle sheath. The minimum ferable to the ' plain' variety. standard breaking strain for No. 2/0 catgut, even 5. The finest possible sizes should be used in when knotted, is 3 lb. This bears out the ex- preference to thicker sizes. periments of various workers who advocate the use In conclusion, the following quotation from of fiher catgut sutures than those commonly used, Mikulicz is offered with respect and sincerity:- with No. o for fascia as the thickest recommended, 'Je reconnais le bon chirurgien, non pas a la down to No. 3/0 or No. 4/0 for muscle, peritoneum fafon dont il coupe, mais a la faFon dont il sait and subcutaneous tissue (Howes, I929, I941). recoudre.' Suspected infection in a wound need not be a BIBLIOGRAPHY reason for using thick catgut; besides the addition Protected by copyright. of 'thick reaction' to the bacterial dis- FANDRE, A. (i944), 'Le Catgut,' Masson et Cie, Paris. catgut WILLIAMS, F. E. (1936), 'Alcohol and Sporing Organisms,' turbance, it is by no means certain that a moderate Med. Jour. Australia. HOLDER, E. J. (I939), ' Surgical Sutures and Ligatures,' E. & S. infection speeds up the absorption of catgut ex- Livingstone, Edinburgh. In a of a number of HOLDER, E. J. (1946), 'Desirable Factors in Surgical Sutures,' cessively. summary large Wm. Blackwood & Sons, Ltd., Edinburgh. abdominal wound disruptions, it was found that JENKINS, H. P., et al. (1942), Arch. Surg., 44, 88I, 984. JENKINS, H. P., et al. (1942), Ibid., 45, 74. the cases in which infection was present disrupted JENKINS, H. P., et al. (1942), Ibid., 45, 323. considerably later than the clean cases. HOWES, E. L., and HARVEY, S. C. (I929), New Eng. J. Med., 200, I285. Furthermore, with the considerable improve- HOWES, E. L. ( 4x), Surg. Gyn. and Obst., 73, 319.

HIND-QUARTER AMPUTATION http://pmj.bmj.com/ By L. P. LE QUESNE, M.A., F.R.C.S. Second Assistant, Surgical Professorial Unit, Middlesex Hospital

Hind-quarter amputation was first performed in In most cases the operation is performed for

i891 by Billroth (1902), but it was not until i895 primary malignant tumours of the bones or con- on September 25, 2021 by guest. that a successful result was obtained by Girard nective tissues of the pelvis, or for similar tumours (I895). Since that time the operation has been in the upper third of the thigh which have ex- performed by many surgeons with increasing 'tended too far proximally to allow of disarticula- success. Pack and Ehrlich (1946) report that 132 tion through the hip-joint; typical of the tumours cases are recorded in surgical literature over the necessitating this procedure are those illustrated in last 50 years. Sir Gordon Gordon-Taylor, in I946, Figs. I and 2. On occasion the operation has been reported a personal series of 2I cases, and since performed for extensive tuberculous or chronic that time has performed a further i i such opera- inflammatory disease. of the hip and pelvic bones. tions ; it is largely as a result of his work that this By virtue of their less sinister pathological formidable ablation has been established in this potentialities, the best results are obtained in cases country as a standard procedure in the surgical where the tumour is .essentially only of local management of malignant disease. malignancy, such as infiltrating chondromas of the