You are in: eMedicine Specialties > Plastic Surgery > WOUND HEALING Wound Healing, Widened and Hypertrophic ScarsArticle Last Updated: Jun 26, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Bradon J Wilhelmi, MD, Endowed Leonard Weiner, MD, Professor and Chief of Division of Plastic Surgery, Residency Program Director, University of Louisville School of Medicine Bradon J Wilhelmi is a member of the following medical societies: Alpha Omega Alpha, American Association for Hand Surgery, American Association of Clinical Anatomists, American Association of Plastic Surgeons, American Burn Association, American College of Surgeons, American Society for Reconstructive Microsurgery, American Society for Surgery of the Hand, American Society of Aesthetic Plastic Surgery, American Society of Plastic Surgeons, Association for Surgical Education, Plastic Surgery Research Council, and Wound Healing Society Editors: Christian Paletta, MD, FACS, Professor, Division Chief and Program Director, Department of Plastic and Reconstructive Surgery, St Louis University School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Wayne Stadelmann, MD, Stadelmann Plastic Surgery, PC; Nicolas (Nick) G Slenkovich, MD, Practice Director, Colorado Plastic Surgery Center at Swedish Medical Center; Subhas C Gupta, MD, PhD, CM, FRCS(C), Professor of Surgery, Chair, Department of Plastic Surgery, Director of Plastic Surgery Residency, Director of Comprehensive Wound Service, Department of Plastic Surgery, Loma Linda University School of Medicine Author and Editor Disclosure Synonyms and related keywords: wound healing, hypertrophic scar, scarring, abnormal scars, abnormal wound healing, widened scar, hypertrophied scar, keloid, keloid scar, wound healing problems, wound-healing problems, wound healing complications, wound-healing complications, cicatrix, scar hypertrophy INTRODUCTIONSection 2 of 12
  You were advised his flesh was capable of wounds and scars. —William Shakespeare, Henry IV History of the ProcedureMuch of art and literature depicts violence and wounding as part of the human condition. To wound, and to be wounded, is to be human. Moreover, while many societies perceive prominent scars as disfiguring, some primitive societies use scarification for beautification or ornamentation. For the surgeon, a scar may be the only trademark of the surgical procedure performed, as FitzGibbon has stated, "By your scars you will judged." (FitzGibbon, 1968). In reviewing the origin of the terms cicatrix and scar, the term cicatrix is interesting in itself. Originally, it was the Greek word eschara, meaning a fireplace. These fireplaces were situated in the middle of the house, and, around them, the main domestic activities took place. Because of these activities, and because mischievous children gathered around them, injuries and subsequent scars were so frequent that the name of the cause came to be that of the effect. The use of the word was passed to Italy along the lines of commerce and became cicatrix. From Italy, it moved to France as the word eschare, which now means a crust covering an ulcer. In the British Isles, eschare mingled with the Saxon word scaur, much resembling eschare in pronunciation and meaning. In the Middle Ages, the word cicatrix had wide significance and included any unnatural white mark on the skin; scleroderma, morphea, and "white spot" disease would all fall under the same term. Even white spots, leukonychia, so often seen on toenails, were included under the term cicatrix (Montgomery, 1939). Because abnormal scar formation is unique to humans, animal model research has not contributed much to our understanding and the treatment of keloids and hypertrophic scars. The wide range of suggested etiologies for abnormal wound healing and the wide range of proposed treatments of abnormal scarring indicate that our understanding of these processes is incomplete. For excellent patient education resources, visit eMedicine's Procedures Center and Skin, Hair, and Nails Center. Also, see eMedicine's patient education articles Suture Care, Wound Care, and Removing Stitches. ProblemWhen a wound heals, a scar takes its place. Simple tissues such as fat, connective tissue, and epithelium regenerate, but the skin, being a complex organ derived from 2 germ layers, heals by the formation of a predominantly fibrous tissue, ie, a scar. If the injury sections or destroys the papillary layer of the stratum corneum, a scar will always be formed. Sometimes, this scar is inconspicuous; other times, it may be disfiguring. Examples of disfiguring scars include keloids, widened scars, and hypertrophied scars. Both keloid and hypertrophic scars are wounds that heal overzealously above the skin surface. The difference between a keloid and a hypertrophied scar is that a keloid continues to enlarge beyond the original size and shape of the wound, while a hypertrophied scar enlarges within the confines of the original wound. Although both can be red and raised, keloids continue to grow and hypertrophied scars tend to regress over time. Both can recur after surgical excision; however, the recurrence of keloid scars is more common. Widened scars are wounds that separate during the healing process, usually in response to tension perpendicular to the wound edges. FrequencyHypertrophic scars are more common than keloids. Hypertrophic scars may occur in persons of any age or at any site, and they tend to spontaneously regress. In general, hypertrophic scars are more responsive to treatment. While keloids occur most frequently in black persons, they may occur in persons of any race with a proven tendency to keloid formation. Keloids are 5-15 times more common in black persons than in white persons (Alhady, 1969). This predilection for formation in persons of certain races is not observed with hypertrophic scars. Keloids are more prevalent in persons aged 10-30 years, while hypertrophic scars occur in persons of any age. In general, the risk for either type of abnormal scar diminishes with age (Murray, 1981). Furthermore, the propensity for keloid formation can be familial, genetically transmitted as an autosomal dominant or recessive trait (Omo-Dare, 1975; Rao, 1990). Widened scars can occur in persons of any age. Widened scar formation occurs with no predilection to sex or ethnicity. No inheritance pattern is associated with the risk for scar widening. Widened scars are most commonly found to involve the arms, legs, and abdomen. EtiologyAbnormal scar formation is unique to humans, and, as such, animal model research has not produced much significant information to further the understanding and treatment of keloids and hypertrophic scars. Despite numerous studies, no uniformly accepted theory or explanation indicates which factor initiates keloid or hypertrophic scar formation. Several genetic and environmental causes have been implicated in the etiology of keloid and hypertrophic scars. In both keloid and hypertrophic scar formation, an excessive accumulation of collagen from increased collagen synthesis or decreased collagen degradation occurs (Cohen, 1971; Cohen, 1977). Proposed causes for abnormal scar formation include foreign body reaction and bacterial infections. Almost all abnormal scars are associated with tattoos, burns, injections, bites, vaccinations, trauma, surgery, or infection. Skin tension is frequently implicated in hypertrophic scar formation. Abnormal scar healing commonly involves areas of high skin tension, such as the anterior chest, shoulders, and upper back (Grabb, 1967; Rockwell, 1989; Wilhelmi, 1999). Other factors implicated in the etiology of abnormal scar formation include wound infection or anoxia, a prolonged inflammatory response, and wound orientation different from the relaxed skin tension lines. Keloid formation has a genetic basis, as demonstrated by its predilection for persons of certain races and in certain families. Because keloids tend to demonstrate accelerated growth during puberty or pregnancy and tend to resolve with menopause, hormones (both androgen and estrogen) have been implicated in keloid formation. Other hormones linked to keloid formation include thyroid hormone alterations and melanocyte-stimulating hormones (Crikelair, 1977). Immunologic alterations have been demonstrated in abnormal scars. Specifically, irregular immunoglobulin and complement levels, increased transforming growth factor-beta, and mast cells have been found in abnormal scars (Cohen, 1979; Topol 1981; Kischer, 1983; Shah, 1992). Additionally, decreased tumor necrosis factor and interleukin 1 levels have been found in these abnormal scars (McCoy, 1981; Castagnoli, 1993). Widened scars result from excess tension perpendicular to the wound edges during the healing process. Scar widening usually occurs within the first 6 months of injury. PathophysiologyAlthough multiple factors are involved in abnormal scar formation, studies indicate that keloid and hypertrophied scars result from increased collagen production and decreased collagen degradation. Cohen demonstrated that levels of the collagen-related enzyme prolyl hydroxylase are elevated in keloid-affected skin compared with normal skin (Cohen, 1971). Prolyl hydroxylase is required for the hydroxylation of proline during collagen synthesis, suggesting that collagen overproduction occurs with keloids. Collagen production is elevated in keloid biopsy samples and in cultured fibroblasts derived from keloids (McCoy, 1980; McCoy, 1982). Additional studies show that increased collagen production by cultured fibroblasts derived from keloids persists throughout their in vitro life span; they do not revert to normal after transfer of the lesion to culture (Diegelmann, 1977). No significant differences in DNA content or cellularity are found when keloid dermis is compared with normal dermis. This suggests that each fibroblast is producing more collagen rather than an increase occurring in the number of fibroblasts producing a normal amount of collagen. In keloid formation, excessive collagen production by fibroblasts may be due to the wound environment. Contrary to the increased collagen production theory, keloids and hypertrophic scars may also result from a decrease in collagen degradation. Levels of the collagenase inhibitor alpha-2 macroglobulin have been shown to be decreased in keloid lesions (Langer, 1978). Widened scar formation is thought to result from wound edge separation with tension perpendicular to the healing skin wound. A state of tension exists naturally in skin; wounded skin gapes and becomes elliptical rather than round. Although Dupuytren first noted this property of skin, Langer received most of the credit (Wilhelmi, 1999). Langer studied the direction of these ellipses by stabbing a round-tipped awl into hundreds of cadavers. When a wound is closed opposite to the lines of tension, the chance of widened scar formation is increased. ClinicalUpon clinical examination, keloids and hypertrophic scars are raised above the skin level. Hypertrophic scars are self-limited; they hypertrophy within the confines of the wound. Initially, hypertrophied scars can be raised, red, pruritic, and even painful; however, over time, they become pale and flat. Hypertrophied scars appear worst at 2 weeks to 2 months. Keloid scars can be differentiated from hypertrophic scars by their spread beyond the original wound. Keloid scars tend to remain red, pruritic, and painful for many months to years until menopause. Patients usually have a personal or familial history of keloid formation. Different from hypertrophic and keloid scars, widened scars are flat and sometimes depressed. With adequate wound maturation, these wounds fade to the pigment of the surrounding uninjured skin. Widened scars are not usually red or pruritic. INDICATIONSSection 3 of 12
The most common presenting concern of patients with abnormal scars is disfigurement. However, some patients experience other symptoms in association with their abnormal scar, such as pain, pruritus, and loss of motion from contracture. These other symptoms can be indications for surgical correction of the scar. Determining what type of abnormal scar the patient has is important for treatment planning. RELEVANT ANATOMYSection 4 of 12
Widened scar formation is thought to result from wound edge separation with tension perpendicular to the healing skin wound. The risks of widened and hypertrophic scarring are increased in the areas of the body where tension across the skin is greater. A state of tension exists naturally in skin; wounded skin gapes and becomes elliptical instead of round. While an anatomy professor in Vienna, Austria at Saint Joseph's Academy, Langer wrote about the structure of joints, blood vessels, and lymphatics. However, he is best remembered for his lines (ie, Langer lines). Langer showed that the ellipses, which he called spaltbarkeit, meaning cleavage, occurred along the lines of tension. He used an ingenious technique to demonstrate this concept. He incised around a circular template and noted that the outer skin retracted in varying degrees in different areas of the body. The direction of the wound retraction coincided with his cleavage lines. The Langer diagrams were developed from cadavers in a uniform position, with their extremities in extension. Langer discovered that his lines changed depending on the position of the cadaver. For instance, the longitudinal orientation of a wound in the antecubital fossa changes to transverse when the elbow is relaxed versus when it is in a semiflexed position. Furthermore, Langer found that wound tension was greater in certain areas, such as the sternum, abdomen, and extremities (Langer, 1978). Later, Kocher recognized the surgical importance of the Langer tension lines and advised that surgical incisions follow these lines (Conway, 1938). However, Langer, an anatomy professor, did not intend for his lines to be used as guidelines for incisions. Later, Borges argued that the Langer lines represented lines of cleavage in cadavers and not lines of relaxed tension (Borges, 1984). Furthermore, the facial musculature of a cadaver is often not relaxed; some display a wide-eyed stare or wide-open mouth. Accordingly, Langer lines are quite different from the relaxed skin tension lines of the face. These lines were described by Borges in 1962, and they are probably the most well-accepted guideline for incisions of the face (Borges, 1973). The relaxed skin tension lines follow furrows formed when the skin is relaxed. Unlike wrinkles, they are not visible features of the skin. They are merely derived from the furrows produced by pinching on the skin. These furrows are produced most easily with pinching perpendicular to the lines. When the skin is pinched oblique to the relaxed skin tension lines, an S-shaped pattern is created. Fewer and higher furrows are created if skin is pinched parallel to the lines (Borges, 1973). Closing incisions opposite to the relaxed skin tension lines can increase the risk of widened or hypertrophic scar formation. CONTRAINDICATIONSSection 5 of 12
A potential relative contraindication to scar revision surgery exists when the scar is a keloid because of the risk of worsening the scar. Sometimes, when keloids recur, they become larger than the original. This risk may not be worth the potential benefit for scars in certain anatomic locations. WORKUPSection 6 of 12
Diagnostic Procedures
Histologic FindingsRegarding the histology of abnormal scars, the collagen in both keloids and hypertrophic scars is organized in discrete nodules, frequently obliterating the rete pegs in the papillary dermis of the lesions. While collagen in normal dermis is arranged in discrete fascicles separated by considerable interstitial space, collagen nodules in keloids and in hypertrophic scars appear avascular and unidirectional and are aligned in a highly stressed configuration (Delaunay, 1964; Stewart, 1981). TREATMENTSection 7 of 12
Medical therapySeveral different nonsurgical options have been described to treat abnormal scars. Pressure is thought to decrease tissue metabolism and increase collagen breakdown within the wound (Ahn, 1991). The different methods of applying pressure include the use of elastic bandages (ACE wraps), thromboembolic disease stockings, or Isotoner-type gloves on extremities. Alternatively, custom-fitted compression garments can be used to apply pressure to the more difficult areas, including the neck and torso. Obviously, compression ACE wraps or stockings are not useful for areas such as the head and neck. Because these devices are uncomfortable, patient compliance varies. Unfortunately, for optimal results, these devices must be used for 6-12 months during the maturation of the wound. Silicone gel can be used to treat abnormal scars. Silicone gel has been shown to significantly decrease scar volume when used over time. Studies have demonstrated 80-100% improvement in hypertrophic scar formation (Sawada, 1990; Ahn, 1991; Dockery 1994). The effect of the silicone gel on the scar is believed to be due to wound hydration. The silicone gel is applied to the wound for at least 12 h/d. Patients find it more appealing to apply the silicone to their wounds at night. Silicone gel is gaining popularity because it can be applied to a smaller area for 12 h/d, usually at night. However, skin breakdown, rashes, and difficulty with wound adherence can lead to disuse. Also, certain areas, such as the face, do not lend themselves to the easy use of such devices. Accordingly, steroid injections have become a common nonsurgical option in the treatment of problem scars. The steroid used for intralesional injection is triamcinolone (Kenalog). Triamcinolone injections have been the standard treatment to induce flattening, fading, and decreased symptomatology of hypertrophied scars (Ketchum, 1966; Vallis, 1967; Griffith, 1970; Kiil, 1977). These injections can be administered as soon as a problem scar is identified. The dose of the injection can vary from 10-120 mg, depending on the size of the scar (Ketchum, 1966). An algorithm has been described that recommends the use of a triamcinolone injection for thin-to-wide hypertrophied scars and silicone for very wide hypertrophied scars (Nicolai, 1987). Some patients prefer triamcinolone injections to avoid applying and wearing the silicone every day for 6-12 months, especially on body areas where adherence is poor, such as the face, palms, and soles of the feet. Some patients also prefer triamcinolone injections when compression therapy may not be an option because of the location of the wound (eg, on the face). Minor adverse effects of triamcinolone injections include hypopigmentation and subcutaneous atrophy (Darzi, 1992). No time constraints exist regarding when the steroid can be administered. Some inject steroids at the time of the wound repair or scar revision. Several studies describe early use of steroid injections to treat hypertrophic scars. In general more favorable response to steroid injections is seen in the treatment of hypertrophic scars over keloids. Other nonsurgical options that have been described include vitamin E therapy, zinc oxide therapy, antineoplastic agents, and immunotherapy. Surgical therapyIf nonoperative measures are unsuccessful in the treatment of abnormal scars, operative intervention can be considered. Certainly, the best treatment of abnormal scars is prevention. Closing wounds to orient the wound along the relaxed skin tension lines is important. A standard practice often used rather subconsciously after excision of a lesion involves assessing the direction of least tension based on the configuration of the edges of the wound or by pinching the wound. The first-line procedure used for scar revision is fusiform excision. In general, fusiform excision does not require lengthening the scar. In order to avoid canine auricles, ensure the wound has a length-to-width ratio of 4:1. Fusiform excision is most applicable to short wounds oriented along relaxed skin tension lines. The Millard flap procedure is similar to fusiform excision, but it involves preserving the scar and its connection to the underlying fat (see Image 1). The skin is incised in a fusiform fashion around the scar to the subcutaneous level (see Image 2). The scar is then deepithelialized, and the skin edges are approximated over the deepithelialized scar. The Millard flap technique is most suitable for widened, depressed scars. Scars not oriented along the relaxed skin tension lines can be modified with a Z-plasty procedure. Limbs of equal length are created for the Z plasty. The angle of the Z dictates the length of scar tension distribution and elongation (eg, 30° for 25%, 45° for 50%, 60° for 75%, 75° for 100%, 90° for 120%). The W-plasty technique for scar revision is similar to Z plasty because of the result of breaking up a straight-line scar into a pattern that is less conspicuous. Similar to a fusiform excision, W plasty involves the removal of skin; therefore, avoid this method if significant tension is present across the wound edges. The technique of W plasty is time consuming and challenging; therefore, it is less popular. W-plasty scar revision is most suitable for scars along relaxed skin tension lines; scars with a bowstring contracture; short, depressed scars; and facial scars (see Image 3). Tissue expansion and serial excision can be considered for larger scar revisions when excess wound tension is predicted (Wilhelmi, 1998). If more than 2 serial excisions are expected, tissue expansion is preferred. Finally, other procedures that have been described to treat scars include dermabrasion, cryosurgery, and laser therapy. Widened scars are treated differently than hypertrophied scars. Widened scars can be flat or even depressed. Therefore, the administration of intralesional steroids is not recommended; these agents could worsen the depression. Widened scars are best treated with the Millard 2-flap technique over a deepithelialized scar. This technique provides soft tissue fill under the approximated wound edges (see Image 2). Furthermore, if the widened scar recurs, the risk for another recurrence can be minimized by reorienting the wound tension along the lines of relaxed skin tension. Other adjuncts described in the treatment of widened scars include the injection of fat grafts or other tissue substitutes. However, these materials are known to resorb with time. When oriented close to the relaxed skin tension lines, hypertrophic scars can be excised in a fusiform fashion. If the hypertrophic scar developed because of excessive tension across the wound as a result of unfavorable wound orientation, Z plasty can sometimes help reorient the wound to distribute tension in a different direction to minimize the risk of recurrence. Postoperatively, compression garments and silicone gel are encouraged for 4-6 months to optimize the result and decrease the risk of recurrence. Patients are encouraged to refrain from strenuous activities for at least 6 weeks, until which time the wound achieves approximately 80% original wound tensile strength. Patients are monitored for 6 months postoperatively to detect and potentially circumvent recurrences early. COMPLICATIONSSection 8 of 12
Postoperatively, patients are at risk for hypertrophic scar and widened scar recurrence. Other risks are similar to any procedure and include infection, hematoma, seroma, and painful or unattractive scarring. OUTCOME AND PROGNOSISSection 9 of 12
The risk of recurrence is significant for both hypertrophic and widened scars, and it is increased with repeat operations. The overall risk rate for a recurrence of hypertrophic scars after excision is approximately 50-100% (Berman, 1998). FUTURE AND CONTROVERSIESSection 10 of 12
In conclusion, wound healing requires 1 year, during which time the surgeon and patient should observe for and expect improvement. Once the scar has had an opportunity to mature, scar revision can be considered. However, because the recurrence rate associated with abnormal scars is high, the surgeon and patient must have realistic expectations regarding the outcome of this revision. Webster states "The great ignominy of the plastic surgeon is his inability to remove a scar without leaving another one. The best we can do is occasionally improve on another surgeon's scar while indeed he may be improving on several of ours." (Gillies, 1957). MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Wound Healing, Widened and Hypertrophic Scars excerpt Article Last Updated: Jun 26, 2006 | |||||||||||||||||||||
