51

SUTURES AND LIGATURES IN SURGERY L. CUTAJAR M.D., F.R.C.S. (Eng.), F.R.C.S, (Edin.)

History of suture mltlt;::r~al dra;nage of wounds and the arrest of bleeding by ligature rather than py The history of sutures is largely a re­ cauterising with boiling tar or hot irons as flection in miniature of the major phases was then customary. in the history of surgery itself. The earliest John Hunte-r and his students, Aber­ known text on surgery is found in the nethy and Astley Cooper, favoured the Edwin Smi,th papyrus (circa 3000 E.C.) ligaiion of arteries. Lembert dsscri.bed the where it is recorded that the ancient Egy­ technique of successful suture of the in­ pUans were already aware of the import­ test;ne by apposition of serosa to serosa. ance of approximating the edges of a At this time ligatures were generally J)2cerated wound. For th's purpose they non absorbable and, of course, non-sterile. used strips of Hnen cloth. In India about Surgeons usually left the ends of the this time- dried animal intestines were be­ ligatures long and extending i:mt of rthe ing used as ligatures while in China wounds. The introduction of antisepsis by threads were employed for the same pur­ Lister revolutionised surgical technique. In pose. 1908, Lister demons·trated that by soaking Even the origin of modern skin clips catgut, in h:s carbolic solution it could be is hallowed ·in antiqUity. About the year left ,in the tissues and the wound closed. He 1000 E.C. giant ant or beetle were used, in first used plain catgut ligatures but after India, to clip wound margins together - extensive research he developed chromic these we·re the original skin clips. catgut. By the sixth century E.C. several The Ispectacular advances in organic materials had been modified and adapted chemistry, in the physical sciences and in for use as sutures, including , silk, engineering technology which characterise animal , strips of leather and the last three decades have led to the in­ hair. troduction of an array of new suture Hippocrates (500 B.C.) stressed the materials partticularly th(, metallic wires importance of closing op~n wounds and he and the synthetic non-absorbable fibres. further advocated the ligation of bleeding vessels. Galen, whose teachings were des­ tined to dominate the practice of surge-ry The 'ideal' suture material for the next fifteen centures, also ligated arteries and makes spec~al mention of cat­ The ideal suture material should: gut: "Select from those materials that sub­ 1. have no delaying effects in the stance which is least putrescible, such as course of healing; very ,thin catgut which rots easily and 2. retain its tensile strength un­ quickly falls from the vessels." impaired for an indefinite period; In the thirteen century A.D. there was 3. be inert ,in the tissues. re-awakening of interest in the techniques Such a suture has yet to be developed. of wound suture and vessel ligation. Theodoric (1205 - 1296 A.D.) and Mun­ dinus (1275 - 1326 A.D.) both wrote ex­ Classification of sutures tensively on the subject. Ambroise Pare (1510 - 1590) whose The differ.:mt types of absorba,ble and extensive experience of war wounds was non-absorbable sutures are summarised in unparalleled, advocated the cleaning and Table 1. 52 TABLE 1 Advantages of catgut Classification of suture materials 1. as it is absoribed it is less likely to form sinuses if the wound turns A. Absorbable sutuJ:es septic. Natural: Catgut 2. it is valuable in situations where a COllagen non-absorbable suture might act as others (e.g. skin, fascia la­ a nidus for a foreign body, such as ta, kangaroo ). in joints, the biliary tree and the Synthetic: POlyglycOl!c acid urinary tract. 3. in suturing the mucosa of the ga­ B. Non-absorbable sutures stro-intestinal tract where a non­ Natural: Sllk absorbable suture might cause Silkworm gut chronic ulceration or haemorrage. Cotton 4. in certain situations it might be used as a skin suture e.g. scrotum, Hair vulva, pe,rianal region. In this sit­ Synthetic: : (mono­ uation removing a non-absorbable filament or multJilamcnt). suture might be painful. ('Dacron,' 'Ttf­ Ion,' 'Terylene'). Disadvantages (shee1ting or 'Marlex'mesh-. 1. Its preparation is complex and in­ Poypropylene. volves considerable expense. The Metallic: Stainless steel source is undeniably septic and Tantalum sterllisation is a problem. Silver 2. It tends to lose its tensHe strength Aluminium. quickly and cannot be used where continued support is necessary ba­ Absorbable sutures cause healing is naturally slow, as in fascia. Catgut (plain and chromic) 3. It frequently tends to cause an in­ tense tissue reaction which is not Catgut is the most widely used suture always desireable (Lawrie, 1959). material. As described above, it has stood 4. Knot holding is still not ideal. the test of time having been used for its Plain catgut has many other dis­ pn3sent purpose since the earliest medical advantages of its own. The knots are un­ records were made. reliable, it causes an intense tissue reactio21 Surgical catgut ,is prepared from the but quickly loses its tensile strength so that submucosa of small intestine. Ex­ it is useless as a scaffold after three days. cised intestine is mechanically cleared at Many surgeons have completely dropped the abattoir, packaged and deep frozen. At plain catgut from their armamentar:ium for the suture factory they are thawed out, this reason. washed and hand stripped of loose fat part­ icles. Each piece is then split into ribbons Polyglycolic acid (P .G.A.): "Dexon" which are further mechanically processed to remove mucosa, serosa and' muscle leav­ Recently, a new completely synthetic ing a thin ribbon of submucosa. Further .absortb8!ble suture has become available. It treatment of the submucosa ensures that . is composed of polymerised hydroacetic only pure collagen fibres are preserved: acid (polyglycolic acid). It is a non-tox',c, this is the plain catgut. Treatment w~th non-collagen product; it is flexible and can chromium salt will harden the gut and slow be handled like silk. It is available in all down its absorption by tissues: this is the the standard gauges, including those used chromic catgut. with all tYP2S of atraumatic needles .. 53

P.G.A. retains a high percerltage of its synthetic sutures such as Nylon, Teflon and initIal tensHe strength during the first two Dacron (Dettinger & Bowers, 1957; Postle­ weeks after implantation, the most critical thwait et. al. 1959). per~od of wound repair. Catgut, on the Whereas absorbable sutures have little other hand, loses at least half its strength €ff2ctive str.:mgth after two weeks (Haxton, in the first five days. 1963) the majority of synthetic mateTilals Unlike catgut, P.G.A. is very inert maintain their strength in tissues for long causing only a very mild tissue reaction periods. Maloney (1961) in reviewing both in clean and in infected wounds. Th~ flylon used in hernia repairs, reported that different response can be explained on the monofilament nylon still retained 70% of basis of the different modes of absorpt~on its initial strength after eleven years of the two materials: catgut is absorbed by whereas multifilament nylon was fragment­ proteolytic enzymatic digestion whereas ed and useless after six months. Propylene P.G.A. is absorbed by hydrolysis. is the best monofilament in this respect. Used as a skin suture, P.G.A. g:ves ex­ Metallic sutures maintain full strength un­ cellent cosmetic results. The sutures need til they break. not be removed as they are absorbable. Non-~1bsorbable sutures should not be The advantages of this in paediatric sur­ used in the presence of infection as they gery are obvIous while adult patients also give rise to wound sinuses which persist been used successfully in bowel anastom­ until the suture is removed or extruded. appreciate being spared the apprehension The braided sutures are much more of having their sutures removed. As a corol­ troublesome in this respect than the mo::o­ lary to the above, patients can be dis­ filament ones. charged home earlier once the risk of early complications has passed. P.G.A. has also osis. On theoretical grounds one would ex­ Conclusions pect P.G.A. to hold an advantage over cat­ gut in view of its m;nimal tissue reaction. The ideal suture material would be a There is now experimental evidence that perfect union of easy sterilisation, adequate this in fact so (Echeverria et. aI., 1970). tensile strength, handLing ease, absence of . foreign body reaction, and complete tissue Non-absorbable sutures absorption. Such a suture has yet to be de­ veloped. Ho,wever, technological progress A non-absorbable suture is one that is and experimental research will surely made from a material that is neither digest­ provide the answer in the not too distant ed nor abso,vbed during the process of future. wound healing. The buried suture becomes encapsulated with fibrous tissue and re­ mains permanently in the tissues except References when surgically removed or extruded. Natural sutures, Eke s:lk, silkworm 1. ECHEVERRIA S., Surgery, 131, 1, 1970. gut, cotto!!., linen and hair have been used 2. DETTINGER, G.B. and BOWERS, W.F., since the earliest days of surgery. The same Surgery 42, 325, 1957. applies to the metallic sutures. More re­ 3. HAXTON H., Brit. J, Surg. 50, 534,. 1963. cently synthetic non-absorbable sutures 4. --LA WRIE, J.?, Brit. J. Surg. 46, 634, 1959. have been used such as nylon, Dacron, Tef­ 5. -MADSENj KT., Surg. G;ynec, Obst~t. 97, 73, Ion, Terylene and polypropylene. 1953. Non-absorbable sutures cause far less 6. MOLONEY, G.K, Brit. J. Surg. 48, 528, 1961. tissue reaction than the absorbable ones 7. POSTLETHWAIT, R.W., Surg. Gynaec., (Madsen, 1953). The least reactive are the Obstet. 108, 555, 1959.