الفهرس 
The Healing CascadeOnly 14 pages are availabe for public view
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Abstract
Scars are one of the big challenges that face plastic surgeons. The consequence of wound healing process raises concern; that may have a psychological effect on the patient. Scars especially in exposed areas such as the face presents a big problem. Patient’s even males may try to camouflage such scars by the use of extreme make up.
Wound is described as disruption of tissue integrity. the normal healing cascade begins with an orderly process of homeostasis and fibrin deposition, which leads to an inflammatory cell cascade, characterized by neutrophils, macrophages and lymphocytes within the tissue. This is followed by attraction and proliferation of fibroblasts and collagen deposition, and finally remodeling by collagen cross-linking and scar maturation, Despite this orderly sequence of events responsible for normal wound healing, pathologic responses leading to fibrosis or chronic ulcers may occur if any part of the healing sequence is altered.
Although the phases of wound healing are relatively fixed in an orderly progression of events, the rate of healing in any of the phases can be regulated by many factors. Healing is affected by the local and general condition of the patient. The presence of infection, foreign bodies, or blood clots and other local factors could delay healing. Other systemic factors as age, nutritional status, and metabolic condition will also affect the healing process.
The best prognosis for successful wound healing is found with smooth, closely adjusted wound edges, without substantial tissue loss or presence of foreign bodies, in a well vascularized area, all this lead to healing by what is called first intention. In some instances, when the edges of the wound are widely separated as in cases with sever tissue loss healing occur by secondary intention that lead to scar formation.
stages of wound healing proceeds in a cascade. When healing deviates from its orderly pattern, scarring results. Changes that may occur in the normal organization of collagen, collagenase activity, amount and density of the fibroblasts, all lead to different types of scars. Decrease in collagenase results in a hypertrophic scar. While increase in the hyaluronidase causes keloid formation, on the other hand collagen destruction leads to atrophic scars. Although contraction is an active biological process occurs during wound healing, yet it may lead to contracture deformity when there is inadequate skin.
There are different ways in management of scars. This could be surgical and non surgical. Surgical methods include: excisional surgery with closure which have high incidence of recurrence, cryosurgery, and collagen and fat injection. Non surgical methods include: chemical peeling, pressure dressing, and silicon sheets. But none of these methods had proved to give good satisfactory results.
Laser was introduced by Theodor Miaman in the early sixties. Laser light has certain properties that make it useful armamentarium in the field of medicine. The first laser used in the treatment of scars was a continuous wave argon laser. Results, however, were transient and scar recurrences were common. Similar recurrences were observed when hypertrophic scar and keloids were treated with continuous-wave carbon dioxide laser. Scars universally recurred within one year after continuous-wave carbon dioxide.
By the early 1990s, the first series on the successful use of the 585-nm pulsed dye laser (PDL) in the treatment of keloids and hypertrophic scars had been published. In 1994, Alster reported clinical and textural improvement in the long-standing erythematous and hypertrophic scars following PDL treatment.
Hypertrophic scars and keloids showed improvement up to 80%, after 2 PDL treatments. Keloid sometimes needs more treatment to give desired results. Intralesional steroid injection in combination of PDL, showed successful results in resistant scars. Neodymium: Yttruim-Aluminum-Garnet laser (Nd: YAG) results in softening, flattening, and reduction in size of keloid.
In 2003, Nouri and colleagues showed that the 585-nm PDL can improve surgical scars when used on the day of suture removal. Laser induces tissue hypoxia through selective photothermolysis of the capillaries, subsequent collagen realignment by its thermal effect.
Atrophic facial scars treated with carbon dioxid and Er: YAG laser have been popular in the recent years. Er: YAG lasers are 10 times more selective for water than carbon dioxid. It also showed decreased postoperative erythema, soften the transition between the atrophic skin and the intact skin surrounding it, and stimulate collagen production within the atrophic area. Each type of laser should be properly chosen for the proper type of scar.
Treatment of scars will remain a problem regarding the choice of the best line of management to achieve the satisfying desired results for both; doctor and patient.