We have reviewed several published literature search engine sites in an effort to gain insights and glean objective evaluations of the global impact of scars, and found few, if any, referenced texts or studies. This deficiency is similarly noted by others.14 We found this rather difficult to appreciate at first given its incidence, and yet perhaps not so surprising given how challenging the problem is to define. The most commonly available reviews on the topic involve pathologic scar development after burn injury. This is intuitive, as pathologic scarring is a more frequent complication after burns as compared with other types of injury or surgery.
The constellation of complaints surrounding scar formation may vary somewhat depending in part on its origin. For example, postsurgical scars often are subjectively described utilizing the parameters of pain, itching, and fragility, whereas burn scars tend to have more impact on the quality of life owing to contractures, ulcerations, and other aspects.15 In 2003, Bombaro et al.16 attempted to review the prevalence of HTS in their burn patient population. Whereas their initial review documented no cases of HTS in 30 Caucasian patients, a retrospective analysis of 110 patients established a prevalence of 67%. The authors then concluded that an accurate understanding of the prevalence of HTS was not known, and iterated the need for accurate studies to better define this
critical data.
A recent publication from Germany by Mirastschijski et al.17 in 2013 reviewed burn care costs associated with acute as well as subsequent early rehabilitative and reconstructive care from their largest regional health care insurance provider. In their review, the total cost of reconstructive and rehabilitative care was estimated to be 4.4 times the cost of the acute care. Of note, 96% of their costs were not hospital related but rather reflected costs for related sequelae including physical and occupational therapy, treatment adjuncts such as pressure therapy, silicone, splints, and prescriptions (see Chapter 19). Extrapolated globally using 2006 data, this cost would have amounted to 245 billion Euros, a staggering financial figure. One can only wonder what these financial costs would approximate if psychiatric care, lost productivity, and other pertinent social and societal costs were factored in (see Chapter 24).
Deitch reported on 59 children and 41 adults with injuries resulting from burns. Overall, he found 26% of the burn areas developed HTS. More importantly, burn wounds that healed within 14 to 21 days had a 33% chance of HTS, whereas the rate was 78% if the burn wound took greater than 21 days to heal.18 In 1990, Spurr published a retrospective study looking at the incidence of HTS in children up to 5 years old, comparing outcomes in 1968 and 1984 at their burn center. He found a 50% chance of developing a HTS in both of his study groups.19 Risk factors delineated included women, young age, burns of the neck and upper limbs, >1 surgical operation, meshed grafts, burn severity, and greater time to heal.20 Comparison of pediatric burn survivors with a matched nonburn study group looking at body image measures demonstrated no differences in body image between the two cohorts.21 An analysis of 703 patients with burn injuries by Gangemi et al.22 revealed 540 (77%) developed scarring. Of these, 310 (44%) had HTS, 198 (28%) contractures with scarring, and 34 (5%) contractures without scarring. HTS induction was initially seen 23 days post-reepithelialization and lasted 15 months. Multivariate analysis revealed the following risk factors: sex (female gender), age (younger), anatomic burn site (face, neck, anterior torso, and upper extremities), number of surgical procedures, and the type of skin graft utilized (meshed). Full thickness burns were a risk factor for the development of hypertrophic contractures. Of these scars, 38% became normotrophic within 2 years, and 24% remained active for many years.
The incidence of HTS after burn injury ranges from 32% to 94%. In the United States, the cost estimate for treatment of these scars exceeded 4 billion dollars (2005).23 A total of 1,798 patients admitted to three Dutch burn centers were followed for a 10- year period; 13% required reconstructive procedures; predictors of reconstructive surgery were burns to the arms, fire and flame burns, number of surgical interventions in the acute phase, and a larger burn size. The majority had more than one reconstruction, most often within 2 years postburn. Frequently reconstructed locations were hands, head, and neck. The most important indications for surgery were scar contractures (72%) and other scar problems such as scar instability, hypertrophy, pigmentation, contour relief, and other issues (28%). The most frequently used techniques were release/excision plus skin grafting. The mean medical cost of reconstructive surgery per
patient was 8,342 Euros; the mean cost (in US dollars) was $9,273 (2014).24
As noted earlier, the true burden of burn injuries globally has not yet been fully realized. In 2004, there were an estimated 11 million burns severe enough to require medical attention; 300,000 of these patients died; 90% of these occurred in low-income countries where timely access to medical and surgical care is difficult.25 As a result, prolonged inflammation and conservative management of deep partial thickness and full thickness burns often eventuates in patholog scarring. Burn injuries amounted to 17% of the disability-adjusted life years (DALYs, the loss of the equivalent of 1 year of good health) lost in adults (15 to 59 years old).
Children under 5 years of age make up 52% of the burn injuries in developing countries.26 The etiology is similar to that in developed countries, unintentional scalding being the leading mechanism of injury. Children aged 1 to 4 were admitted to the hospital at a greater rate than older children and adults. Intentional burn injury accounts for 5% of burn admissions in the United States.27 In India, self-immolation or burn assault accounted for 65% of the fire-related deaths in women in 2001.28
HTS are very dynamic in nature, further complicating the challenge of characterizing them. They are thought to undergo several stages of development and maturation, beginning with a proliferative or active growth phase, an intermediate stage where contractures may complicate the clinical presentation, and finally an involutional phase. These stages progress at different rates and extents depending upon multiple factors such as age, sex, etiology, and area of involvement. It is often quoted that pathologic scars seem to manifest with the same prevalence in both sexes, and yet (depending on which paper you review) the incidence of HTS development appears to complicate healing in women more commonly than in men. Similarly, a higher incidence of keloid presentation has been reported in women. Whether these discrepancies reflect pathophysiology or simply the increased likelihood of one seeking medical attention remains difficult to distinguish. The average age at onset of keloids is 10 to 30 years; it is often noted that individuals at the extremes of age rarely develop them. Borsini et al.29 found that HTS occur more commonly in young patients, and that their scars evolve over longer periods of time as compared with adults. On the contrary, scarring often evolves more rapidly in elderly patients. Hypertrophy appears to be directly correlated with burn extension, infection, and delays in healing. Interestingly, HTS occur more frequently when the burn is caused by flame as compared with electrical or scald injury.
Burn injuries are only one etiologic contributor to the overall challenge of pathologic scars. Individuals of all genetic and racial backgrounds appear to have the propensity to develop them. It is, however, important to note that genetics, familial propensity, and race have long been demonstrated to be risk factors for the development of pathologic scarring. Individuals with darker pigmentation are generally considered to be at most risk for developing keloids. The incidence of keloids in persons with highly pigmented skin is often quoted as being 15 times higher than in persons with less pigmented skin.30 Furthermore, black patients have been noted to have a twofold increase in risk for keloid development as compared with Hispanic and Asian patients.31,32 Interestingly, a random sampling of black individuals revealed that as many
as 16% had reported developing keloid scars. Caucasians and albinos are reportedly least likely to be affected.33 Chinese individuals were noted to be more likely to develop keloids as compared with Indian or Malaysian individuals.30
Lim et al.34 report that 200 million skin incisions are performed annually worldwide, and approximately 170,000 surgical scar revisions are performed in the United States alone. It has also been reported that in Hong Kong alone, 350,000 surgical procedures are performed each year for problematic scars, with more than 40% of patients suffering from pruritus and pain.35,36 In a study by Li-Tsang et al.35 in 2005, patients admitted to the Department of Orthopaedics and Traumatology were screened for HTS formation 30 days after nonburn-related orthopedic surgery conducted from May 2003 to December 2003.36 In their review, the authors reported an incidence of HTS formation of 70%. The incidence of problem scar development in their burn population was felt to well exceed this value. In contradistinction to other published studies that found that the likelihood of developing HTS was very low in the elderly patient population (generally attributed to the slower metabolic rates and diminished skin tensile strength found in the mature patient37), Li-Tsang et al. observed a relatively high prevalence rate among their older patients. This not only implies an increased incidence, but also suggests that the problem may be more severe in the younger Chinese population. It is important to note that although the study was objectively performed and evidence based, it was undertaken rather early in the postoperative period. Longer-term follow-ups would be very helpful in elucidating the overall impact and long-term effects in this study population, as certainly the number of patients with postsurgical wounds far exceeds the number of thermally injured patients. Keloids, although not the intended study subject, can develop from 6 months to 2 years after an inciting cause. This highlights the fact that follow-up periods in most studies are inadequate.38
The incidence of HTS formation following cleft lip repair, although perhaps not often reported, appears to range somewhere between 1% and 50%. Cleft lip is one of the most common congenital anomalies requiring surgical correction, occurring at a rate of 79.1 per 100,000 live births.39 A review of 186 charts of patients who underwent primary cleft lip repair by a single surgeon at Children’s Hospital Los Angeles from June 1990 to June 2005 identified HTS in 25%. The incidence was elevated in patients with darker pigmentation, although no gender differences were noted.40
Patients who have suffered facial trauma and scarring have been noted to experience significant negative social and functional impact. A retrospective study performed at Yale included healthy 8- to 45-year-old individuals who experienced a facial laceration of 3 cm or greater and/or a fractured facial bone requiring operative intervention within 6 months to 2 years of presentation. Patients experienced a statistically significant lower satisfaction with life, more negative perceptions of body image, a higher incidence of PTSD, higher incidences of alcoholism, and an increase in depression. The authors also noted a significantly higher incidence of unemployment, marital problems, binge drinking, jail, and lower attractiveness scores.41 These findings are, unfortunately, not unique and complement the clinical experiences of psychologist, psychiatrists, and other investigators in the field.42–45 Interestingly, patient-rated facial scar severity was not
necessarily predictive for self-esteem and depressive symptoms in patients. This observation was also noted by Hoogewerf et al.46 in their study of thermally injured patients. The authors concluded that routine psychological screening should be performed during hospitalization in order to identify patients at risk and to optimize their treatment.
Demographically, the incidence of injuries occurring in high-income countries has been noted to be decreasing in recent years, albeit at a slower rate than the incidence of illness. This is in contradistinction to low- and middle-income countries, where both death and disability from injuries are increasing very rapidly. In this latter group, in men aged 15 to 44 years in the Americas, Europe, and the Eastern Mediterranean, more than 30% of DALYs caused either by death or disability were from injury.47