Suturing

Symposium on Plastic Surgery for General Surgeons

Suturing Kathryn Lyle Stephenson, MD. *

The purpose of a suture is to coapt the tissue until the wound gains maximal strength. It should cause minimal interference with the biologic healing process. Despite the development of nonabsorbable sutures and absorbable sutures that produce minimal tissue reaction, the fact remains that a foreign body is being introduced into the body and each penetration of the needle and suture inflicts further trauma. Van Winkle and Hastings31 have emphasized that: Sutures should be as strong as normal tissue through which they are placed. If the tissue reduces suture strength with time, the relative rate at which the suture loses strength and the wound gains strength are important. If the suture bio-

logically alters the healing process, these changes must be understood.

The suture used should not be larger than absolutely necessary. Needles should be sharp and smooth. Tearing, crushing and twisting of the suture is to be avoided for to do so produces more necrotic debris and, more importantly, jeopardizes the blood supply which is requisite for healing. Too much tension with strangulation of tissue, especially the capillary vessels, is perhaps the most common cause of unsatisfactory healing and a poor scar. However, there are certain situations when a surgeon fully aware of the damage so inflicted will justifiably close a wound under tension in preference to an alternate solution of the problem. While suturing the normal biologic events in the healing of a wound should be recalled. Howes and Harvey15 in 1935 in their classic paper on wound healing divided the healing of the wound into three phases. More recently considerable further studies of this problem have been undertaken and are still in process. As a result, emphasis has been placed on the variation in rate of healing of different types of tissue and the entire process is better understood. The "lag" or substrate phase of healing extends from the initial wounding to the 4th to 6th day in the human (Fig. 1). The fibroblastic phase lasts from days 4 to 6 to the 15th but is not

':'Santa Barbara Cottage Hospital, Santa Barbara, California

Surgical Clinics of North America- VoL 57, No.5, October 1977

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KATHRYN LYLE STEPHENSON

Figure 1. Schematic representation of microscopic changes seen in a healing full-thickness excised wound. A, Immediately after operation. The wound cavity is filled with a blood clot (A). At the base is a cell-rich exudate (B). Epithelium at the edge shows thickening (C). Dermis is the shaded area (D) and a transected hair follicle is present (E). Similar transected appendages can be seen in the wall of the excision. B, Two to 3 days after injury. The surface clot (A) has retracted, and subclot cellular exudate (B) has increased. Epithelium is advancing mainly from edges of the wound (C), but also from transected appendages. New connective tissue (D) is beginning to form at the base of the wound and the fatty layer shows increased cellularity. C, By about the 6th day after injury, new epithelium from all sources has extended almost across the wound (A, B). New connective tissue at the base of the wound is proliferating and new capillaries (C) are invading granulation tissue from underlying fatty tissue. D, Wound between 8 and 10 days after injury. Epithelium (A) has covered the excision and has thickened considerably. The wound is being further closed by active contraction of surrounding tissue (B). New connective tissue, in the form of highly vascular granulations, has filled the wound cavity. Later, vascularity will deiminish and a dense collagenous scar will underlie new epithelium. (Modified from Gillman, T., in Gould, B. N. (ed.): Treatise on Collagen, Vol. 2B. New York, Academic Press, 1968.)

sharply demarcated from the third phase, that of maturation, which may take months or years. During the "lag" phase characterized by inflammatory reaction with removal of debris, deposition of noncollagenous proteins and glycoproteins, and the migration of fibroblasts and epithelial cells, the wound is held together by fibrin glue and a thin layer of epithelial cells. During the fibroblastic phase when the proliferating fibroblasts synthesize mucopolysaccharides, glycoproteins; and collagen which is formed into

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fibers, there is a rapid increase in strength of the wound and the collagen content is increased to the maximum. This maximum wound content of collagen is not to be confused with maximal tensile strength. During maturation, tensile strength increases at varying rates in different tissues as the collagen fibers become more insoluble and remodeled by interweav~ng and closer packing of the fibers (Fig. 2). The ideal suture for each tissue would be that which held until the strength of the wound was equal to that of normal tissue and then was promptly and completely absorbed. Flexibility and uniformity in handling and knot-holding ability are charactertistics that are desirable. As yet such sutures are not available. Polypropylene (Prolene), stainless steel, and monofilament nylon (which loses 20 per cent of its strength in' 1 year) do function sufficiently long but these are nonabsorbable. There are certain situations which mitigate against their use, notably in some viscera. The absorbable sutures polyglactin 910 (Vicryl) and poly glycol acid (Dexon) cause minimal tissue reaction and· are to be preferred. However, polyglactin 910 (4-0) loses 60 per cent of its tensile strength at the 18th day and is completely absorbed in 90 days. Polyglycol acid (4-0) loses 80 per cent tensile in 14 days and is absorbed in 90 days.2 It should be noted that the breaking strength at 21 days requires 1.6 lb of force and for polypropylene, 0.66 Ib. 36 The amount of tension that will be 'exerted on a wound in a human cannot be accurately assessed but will depend on the muscular strength, activity, amount of adipose tissue, and the age and health of the individual and other factors. Fasica Fascia is slow to regain tensile strength. According to Peacock,25 it regains 50 per cent of the original strength in 50 days and 80 per cent in 100 days postoperative. The strength of closure of a wound depends on this tissue. It may take over a year to approximate normal fascia. Stainless steel, polypropylene, and nylon fulfill this requirement. Since stainless steel can be fragmented with movement and is less elastic and more apt to cut tissue, polypropylene is the suture of choice.

Figure 2. Collagen fiber net· work in a lOlL section of normal rat skin, showing interlacing of fibers. Scanning electron micrograph. x1000. (Reproduced from Forrester, J. C., Zederfeldt, B. H., Hayes, T. L., and Hunt, T. K., in Dunphy, J. E., and Van Winkle, W, Jr. (eds.): Repair and Regeneration. Copyright 1969, McGraw-Hill Book Company. Used with permission of McGraw-Hill Book Company.)

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It has been found that the greater the stress to which a wound is subjected, the stronger will be the scar tissue that is formed. 28 Therefore, closure of this tissue under slight tension insufficient to cause strangulation has been recommended. 25 Horizontal or mattress sutures or a continuing running suture are all appropriate, although the intermittent are preferred because of the occasional suture that might not be of uniform strength.

Subcutaneous Tissue Subcutaneous fat heals rapidly. Fat following trauma becomes highly cellular. This tissue is closed not only for the purpose of controlling capillary hemorrhage and to prevent the accumulation of tissue fluid and blood in a dead space (all pablum for bacteria and leading to infection and fibrosis), but also to form a firm base to support the union of skin. It has been postulated that it is essential for dermal unionY Polyglactin 910 or poly glycol acid is satisfactory for ligation of vessels or sutures for this tissue if properly used. Interrupted or of mattress type is generally used. An attempt should be made to evert the tissue. The sutures should be minimal in number. Skin Suturing of skin is of special importance because not only are we concerned with the firm closure of the wound but also with the esthetic results. Although inseparable in the healing process distinction for convenience sake will be made between epidermal and dermal healing. The epithelial cells within 26 hours start to migrate while the dermal layer is still in a state of rest. The epithelial cells follow down the dermal margin to obtain a base on which to progress to meet a like cell of the opposite wound margin. Thus, at the wound margin and around each stitch there is invagination of epithelium which will proceed down into the dermis if the suture penetrates the dermis and will continue until the suture is removed (Fig. 3). The strength of the wound depends on the healing of the dermis. The organization of the collagen fibrils does not begin until day 4 to 6 and achieves only 20 to 30 per cent of normal by the 14th to 21st day and 60 per cent of its strength by the 120th day. The fact that it continues to mature for 6 months and longer presents a problem for the surgeon. WOUND CLOSURE. From these studies it is apparent that the wound needs support for approximately 4 months and possibly longer to prevent stretching of the scar. Ignoring the cross striations that may result from the too tightly tied suture that does not allow for edema but concentrating on the down growth of epithelium along the needle suture tract, no epidermal sutures would be desirable. However, tape closure does not permit the fine adjustment of epithelial margins or eversion. Dermal closure for adequate support until healing has occurred demands a durable suture. A monofilament suture with buried inverted knots fulfills this criterion. A running pull-out monofilament suture is often used in scar revision and is suitable where the incision is a right

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Figure 3. The healing of an incised, sutured, skin wound. A, Note inverted epithelial edges immediately after operation. Fibrinous exudate can be seen between cut edges of the incision, above which is a small surface clot. B, Epithelial edges are thickened and are beginning to grow down in contact with the cut surface of dermis. Note round cell infiltration around the suture tract (reactions to the suture are shown only on the right, for simplicity). C, Epithelial hyperplasia and invasive "spur" formation are marked. This growth also extends down the suture line. Fibroblasts are invading the wound from subcutaneous fat, but dermis and dermal fibroblasts are inert. Fibroblasts (X) also surround the epithelized suture tract. In other areas, giant cells (Y) are noticeable. D, Capillary growth is proceeding upward from subcutaneous tissue and fibrosis is far advanced. Invasive epithelial spurs have regressed, leaving small round keratinizing epithelial "pearls" behind. Epithelium is beginning to straighten at the line of incision and the scab is being pushed off the wound. Epithelization of the suture tract is being narrowed by vigorous round cell and fibrotic reactions. E, Epithelial and connective tissue reactions have abated and epithelium thins and assumes the late scar-like appearance. Deeper, collagen deposition is marked although elastic fibers are absent until very late in the course of healing. (Reproduced by permission from Gillman, T. and Penn, J., Med. Proc. 2:121, 1956.)

25 days to year. after operation

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angle and more or less in a straight line. Usually because of the tracts at the point of entrance and exit they are not retained for 120 days. If the wound is along a line of relaxation, which lines are at right angles to the muscle, or has lost its elasticity due to age and if adequate undermining has been accomplished, the stress on the wound may be minimal and an esthetically satisfactory scar achieved if the suture is pulled out on the 21st day. In expert hands this method of closure may be superior but it is difficult to obtain equal levels of dermal approximation throughout the wound (Fig. 4). Retained nonabsorbable sutures are more apt to give lumpy scars. 21 Properly placed horizo~tal mattress sutures of the dermis best accomplish eversion of the wound and, supplemented with the minimal number of monofilament nylon or polypropylene sutures 1 to 2 mm from the edge removed within 72 hours, give a good scar without suture marks. Not all wounds are well designed surgical incisions and therefore from a practical point of view other methods of closure of the wound must be considered. The jagged jig-saw wound and some other wounds may be best closed by the placement of full-thickness skin sutures to determine the relationship of the tissues prior to closure of the dermis.

V~rti'cal

Mdttress Suture

00

Buried Cat-gut Suture with knot placed deeply

Intradermal Suture

~Over.~nd-ove.r"

Suture

-Blanket Stltch-

Figure 4. Commonly used types of skin suture. (Reproduced from McGregor, I.A.: Fundamental Techniques of Plastic Surgery. Baltimore, Williams & Wilkins Co., 1965. Used with permission of Churchill Livingstone.)

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Figure 5. To obtain eversion of the wound, the hand must be completely pronated to take advantage of the curvature of the needle .and to obtain a more widely spaced suture at the depth of the wound than at the surface.

These may be tagged with clamps until the dermal sutures are inserted, thus avoiding further trauma to the skin by faulty placement of sutures that will necessarily be replaced. With each insertion of the needle capillaries are destroyed. Polyglactin 910 and polyglycol acid, although effective only until the wound has gained approximately 20 to 30 per cent of its normal strength because of the minimal tissue reaction elicited, are satisfactory in many situations and are used as a horizontal mattress suture in conjunction with intermittent monofilament nylon sutures to produce satisfactory scars of the face. In older individuals with more relaxed skin this type closure has been s~tisfactory on the trunk and the knot is buried at the lowest portion of the skin or subcutaneously. . . . Under certain conditions such as elevation of "a flap, etc., full thickness sutures of monofilament nylon or polypropylene may be appropriate. In such instances extreme pronation on inserting the suture is necessary so that at the depth of the dermis the suture is further from the wound margin and the wound is thus everted (Fig. 5), Contaminated Wound After evaluating the etiology of the wound and the status of the patient, one may deem a contaminated wound (one with less than 106 bacteria per gram of tissue) suitable for closure after lavage and adequate surgical debridement. Polyglactin 910 or polyglycol acid and epidermal sutures of nylon are satisfactory. The wound is closed loosely with the minimal number of sutures in order to permit egress of fluids and avoid additional trauma due to a foreign body.

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Extrinsic Support When should the sutures be removed? The old dictum was-when they have ceased to serve. This depends upon the judgment of the surgeon who determined their function initially and has observed the progress of the wound. Gillman ll and Crickelair3 have stressed that sutures should not be retained beyond the 14th day. The security of the wound depends on the dermal closure and the intrinsic and extrinsic tension to which it is subjected. Epidermal sutures of the face, especially in the patient with sebaceous skin, need to be removed on the 3rd day. In the older patient they can be left in some areas for 5 to 7 days without later evidence. No sutures will be retained longer than necessary but in some situations it may be necessary to retain them longer than 14 days. Secretions indicate delayed healing and the advisability of leaving them longer. A suture mark is preferable to a disrupted wound. Unless a nonabsorbable dermal suture is used, the wound should be supported for a minimum of 21 days, preferably for 4 months. For wounds of the face Steri-Strips are serviceable. Properly applied collodion gauze bandages are time' honored. This type of support is often incorrectly utilized (Fig. 6). One end of the fine mesh roller gauze should be affixed to the skin at right angles to the wound, permitted to dry, and then, while exerting tension on the gauze the opposite end, applied. If used as an initial dressing, a thin strip of emollient gauze is placed over the wound prior to application and care is taken that no collodion is placed on the portion of gauze immediately over the wound. Van Winkle 30 has stated that the process of epithelization is modified according to the moisture of the wound surface.

Figure 6. A, Vaseline, Xeroform gauze placed over the suture line. If an area is abraded, a single sheet of Owens surgical rayon is preferred. B, Gauze fixed to one side of the wound with collodion (nonflexible), permitted to dry, and then stretched over the wound. Collodion is applied while the gauze is held under tension.

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Figure 7. Vaseline dental roll stent to obtain pressure and immobilization.

Histologic examination during the course of wound healing showed that at 24 hours when epithelial migration has just begun, leukocytes had migrated upwards and accumulated within the fibrous tissue immediately below the wound surface. The migrating epidermal sheet passed through the fibrous tissue immediately under the leukocyte layer, thus the superficial1ayer of fibrous tissue and leukocytes were included in the scab. In the moist wound, the epidermal sheet migrated through the serous exudate on the wound surface above the fibrous tissue of the dermis.

This dressing permits oxygen to the wound and one rarely sees a stitch abscess. The bandage is easily replaced and maintained for 3 weeks without too much protest by the patient. In some areas of the body this is not adequate support and elasticized adherent bandages may be necessary to assure immobility. Sometimes it is necessary to resort to splinting. Patients are not amenable to maintenance of support for a protracted period and it is difficult to achieve maintenance for 120 days. Unfortunately, despite the surgeon's assiduous attention to detail there are some patients whose scars will increase in width. Secondary revision will give little or no improvement. Summary Plastic surgeons use sutures for other purposes than the approximation of tissue. They are used to tie over a bolus to close a dead space or maintain a tissue graft in a desired place until it becomes adherent. A bolus of Vaseline gauze over a cotton dental roll is useful (Fig. 7). Sutures may be used to maintain certain tissue relationships until firm scarring will retain this position. Purposeful suturing in contrast to automatic closure of the wound involves the knowledge of wound healing, careful selection of appropriate needle and suture, and the infliction of minimal trauma. Adequate

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KATHRYN LYLE STEPHENSON

postoperative support of the wound is desirable. Careful critical observation of wounds over long periods of time is instructive.

REFERENCES 1. Cohen, I. K.: Wound healing-an overview. In Symposium on Basic Science in Plastic Surgery. St. Louis, C. V. Mosby Co., 1976. 2. Craig, P. H., Williams, J. A., Kavis, K. W., et al.: A biologic comparison ofpolyglactin 910 and poly glycolic acid synthetic absorbable sutures. Surg. Gynec. Obstet., 141 :1, 1975. 3. Crickelair, G. F.: Skin suture marks. Am. J. Surg., 96:631,1958. 4. Dettinger, G., and Bowers, W. F.: Tissue response to Orlon and Dacron suture. A comparison with nylon, cotton and silk. Surgery, 42:325, 1957. 5. Edlich, R. F., Panel, P. H., and Rodeheaver, G. T.: Physical and chemical configuration of sutures in the development of surgical infections. Ann. Surg., 177 :679, 1973. 6. Edlich, R. F., Rodeheaver, G. T., Kurtz, L., et al.: Treatise on the contaminated wound. Symposium on Basic Science in Plastic Surgery. St. Louis, C. V. Mosby Co., 1976. 7. Eilert, J. B., Binder, P., McKinney, P. W., et al.: Polyglycolic acid synthetic absorbable suture. Am. J. Surg., 121 :561, May, 1971. 8. Emmett, A. J: J., and Barron, J. N.: Adhesive suture strip closure of wounds in plastic surgery. Br. J. Plast. Surg., 17:175, 1964. 9. Gibson, E. W., and Poate, W. J.: The use of adhesive surgical tape in plastic surgery. Br. J Plast. Surg., 17:265, 1964. 10. Gillies, H.: Technique of good suturing. St. Bartholomew's Hosp. J., 47:170,1943. 11. Gillman, T. P.: Studies on the repair of cutaneous wounds. Med. Proc., 2:Suppl. 121, 1956. 12. Golden, T., Levy, A., and O'Connor, W.: Primary healing of skin wounds and incisions with a threadless suture. Am. J. Surg., 104:603, 1962. 13. Haxton, H. A., Clegg, F. F., and Lord, M. G.: A comparison of catgut and polyglycolic acid sutures in human abdominal wounds. J. Abdom. Surg., 16:239,1974. 14. Horton, C. E., Adamson, J. E ., Mladick, R. A., and Carraway, J. H.: Vicryl synthetic absorbable sutures. Am. Surgeon, 40:729, 1974. 15. Howes, E. L., and Harvey, S. C.: The clinical significance of experimental studies in wound healing. Ann. Surg., 102:941, 1935. 16. Howes, E. K., Harvey, S. C., and Hewitt, C.: Rate of fibroplasia and differentiation in the healing of cutaneous wounds in different species of animals. Arch. Surg., 38:934, 1939. 17. Kazanjian, V. H., and Converse, J. M.: Surgical Treatment of Facial Injuries. Baltimore, Williams & Wilkins Co., 1949. 18. Ketchum, L. D.: Keloids and hypertrophic scars. In Symposium on Basic Science in Plastic Surgery. St. Louis, C. V. Mosby Co., 1976. 19. Kirschner, M.: Allgemeine und spezielle chirurgische Operationslehre, Vol. 3, Part I. Berlin, Julius Springer, 1935. 20. Klein, L.: Collagen structure and metabolism. In Symposium on Basic Science in Plastic Surgery. St. Louis, C. V. Mosby Co., 1976. 21. Lewis, J. R., Jr.: Facial scars resulting from vehicular accidents. CLIN. PLAST. SURG., 2:143,1975. 22. Madsen, E. T.: Experimental and clinical evaluation of surgical suture materials. Surg. Gynec. Obstet., 97:73, 1953. 23. Miller, J. M., Zoll, D. R., Brown, E. 0., and Howard, F.: Clinical observations on the use of an extruded collagen suture. Arch. Surg., 53:167,1934. 24. Nardi, G. L., and Zuidema, G. D.: Wounds and Infections. Boston, Little Brown & Co., 1961. 25. Peacock, E. E., and Van Winkle, W., Jr.: Surgery and Biology of Wound Repair. Philadelphia, W. B. Saunders Co., 1970, p. 154. 26. Postelthwait, R. W., Willigan, D. A., and Ulin, A. W.: Human tissue reactions to sutures. Ann. Surg., 181:144, 1975. 27. Smith, F.: Plastic and Reconstructive Surgery. Philadelphia, W. B. Saunders Co., 1950. 28. Sussman, M.: Effect of increased tissue traction on tensile strength of cutaneous incisionsinrats. Proc. Soc. Exp. Biol. Med., 126:561, 1967. 29. Thacker, J. G., Iachetta, F. A., Allaire, P. E., et al.: Biomedical properties of skin-their influence on planning surgical excisions. In Symposium on Basic Science in Plastic Surgery. St. Louis, C. V. Mosby Co., 1976. 30. Van Winkle, W., Jr.: The epithelium in wound healing. Surg. Gynec. Obstet., 127:1089, 1968.

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31. Van Winkle, W., Jr., and Hastings, J. C.: Consideration in the choice of suture materials for various tissues. Surg. Gynec. Obstet., 135:113, 1972. 32. Van Winkle, W., Jr., Hastings, J. C., Barker, E., et al.: Effect of suture materials on healing skin wounds. Surg. Gynec. Obstet., 140:7, 1975. 33. Van Winkle, W., Jr.: Epithelization and wound contraction. In Symposium on Basic Science in Plastic Surgery. St. Louis, C. V. Mosby Co., 1976. 34. Van Winkle, W., Jr.: Abnormal healing and its control. In Symposium on Basic Science in Plastic Surgery. St. Louis, C. V. Mosby Co., 1976. 35. Van Winkle, W., Jr.: The healing of skin and visceral wounds and the effect of suture materials. In Symposium on Basic Science in Plastic Surgery. St. Louis, C. V. Mosby Co., 1976. 36. Van Winkle, W., Jr., and Salthouse, T. N.: Biological response to sutures and principles of suture selection. Ethicon, Inc., 1976. 2235 Castillo Street Santa Barbara, California 93105