Keloids, Hypertrophic Scar And Scar Revision

Ideal Scar

It must be thin, level, and have a good color match with the surrounding skin. It must also be flat and level with the skin. It should be a straight, unbroken line that is easy to follow with the unaided eye, parallel to relaxed skin tension lines or on the edge of the aesthetic components.

Factors Affecting Final Appearance Of Scar

Outside the surgeon's authority- The way an injury occurs, where the wound is.  The patient's state of health.  Type of skin of patient. Propensity to leave thick scars. In the surgeon's hands -  Adequate repositioning of injuries.  Surgically removing injured tissue with caution.  Careful treatment of the tissue in the first repair. Wherever possible, align scars in an aesthetically pleasing manner.

Hypertrophic Scars And Keloids

Abnormalities in the physiologic wound healing process and damage to the deep dermis result in the formation of excessive scars. Clinically distinguishing between keloids and hypertrophic scars is challenging.

Pathogenesis

There are three main stages of wound healing: inflammation (48–72 hours), proliferation (3 days–3 weeks), and remodeling (3 weeks–several months). 

In normal tissue, the balance between new tissue biosynthesis and degradation mediated by apoptosis is achieved by platelet degradation, which releases and activates powerful cytokines that recruit neutrophils, macrophages, epithelial cells, and fibroblasts. During excessive scar formation, there is a dysfunction of the underlying regulatory mechanism and persistent inflammation, excessive collagen synthesis, or deficient matrix degradation or remodelling.

Platelets must undergo degranulation during the inflammatory phase, which is the initial stage. They will release cytokines upon degranulation. Every inflammatory cell's chemointeraction is mediated by cytokines. These inflammatory cells will recruit fibroblasts, keratinocytes, and endothelial cells to aid in the proliferation of cells. Myofibroblast assistance will cause remodelling as a result, which will produce appropriate scarring. 

When there is severe scarring, more inflammatory mediators such as TGF β1, PDGF, IGF-1, IL-4, and IL-10 are released, which leads to an increase in the synthesis of collagen, fibronectin, glycosaminoglycan, and TIMP I and II. You will have an excessive quantity of scar development as a result of the elevated number of proteoglycans.

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Differences Between Hypertrophic Scars And Keloids

Hypertrophic Scar

It is an enlarged or ugly scar that stays inside the initial wound's bounds.
The incidence ranges from 40-70% after surgery to up to 91% after burns. The shoulder, neck, presternum knees, and ankle are the sites of predilection. There are no claw-like features present.

There's no hereditary tendency.  The duration is typically 4–8 weeks. Regression occurs for a few years.  Although it is itchy, it is not sensitive.  There's no hyperesthesia or pain.  If the causal cause is eliminated, it does not return following excision.

Keloid

It is an unusual scar that spreads outside the bounds of the initial injury location. 6–16% of African populations experience it. The mandibular boundary, upper arm, cheekbones, shoulders, ears, anterior chest, and posterior neck may all be affected. There are processes resembling claws. 

Transmission within families occurs. It develops on the mid-chest spontaneously in the absence of any known injuries, or it happens years after minor accidents. It does not regress over an extended length of time. It is sensitive and itchy. Hyperesthesia and discomfort may be linked to it. Even after excision, it returns.

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Treatment Of Hypertrophic Scars And Keloids

Silicone Sheeting

For an average of six to twelve months, 8 to 12 hours a day are spent using bedding. Silicone sheeting has the ability to reduce evaporation by over 50%, increasing scar hydration. This is thought to result in a decrease in capillary activity and collagen production. It is possible to apply silicon sheeting beneath the skin's epidermis.

Button/ Pressure Therapy

It can support other therapy or be used on its own.  After a state of tissue hypoxia is induced by pressure, fibroblast degeneration and collagen degradation follow.For 4-6 months, wearing these appliances for 18–24 hours a day yields the best outcomes.

Intralesional Steroids

It is the second line of therapy for early hypertrophic scars and the first line of treatment for early keloids. The response rate to treating keloids solely with steroids is 30–100%. Subjective symptoms of pruritis and pain improved along with parameters like size and elevation. The rate of recurrence exceeds 50%.

Triamcinolone acetonide injections (10–40 mg/ml) are usually adequate for two to three times, while they can occasionally be used for up to six months. Steroids can be used alone, in conjunction with cryotherapy or surgery, or following scar revision. Younger keloids can be fully flattened. Older scars and keloids can soften and flatten only to some extent to provide some symptomatic relief.

Side effects of intralesional steroids

Injection site pain; telangiectasia; hyppigmentation; and dermal atrophy

Surgery 

The recurrence rate following surgery alone is 54–93%. The results of laser therapy are inconsistent or subpar. Poor or mixed pump pulse dye laser performance. Results using a pumping pulse dye laser have demonstrated improvements in scar height, erythema, texture, and symptomatology that lasted for a minimum of half a year after treatment.  It's still unclear if lasers are clearly superior than cold scalpels.

Advantage of laser

Capability to evaporate tissue; Blunders in dissection. When utilized as the exclusive treatment, laser and scalpel excision will both produce subpar outcomes.

Surgery+Steroids 

This combination of surgery and post-operative intralesional steroid injections on a regular basis is considered the current standard of therapy by many.  The recommended dosage for treating keloids in the head and neck is 5–15 mg, given every 14–19 days.

Radiation Therapy Alone

It is taken into consideration for individuals whose keloids are severely deforming, impairing their ability to function, and not improving with less aggressive treatments. The range of response rates is 15–94%.  A dose between 200 and 4500 rads is possible.  It serves as an adjuvant therapy after surgery.

Radiation + Surgery

The dose is comparatively modest, at less than 2000 rads;  The response rate ranges from 33 to 100%. There is still a lot of debate over radiation therapy for benign illnesses.  Saved for the most difficult-to-treat and deformable keloids of the head and neck.

Cryotherapy

Generally successful for hypertrophic scars, for keloids in combination with intralesional steroids; contact/spraying freezing with liquid nitrogen employing freeze-thaw cycles of 10 to 20 seconds.  It can only be used to treat minor scars.  Pain and blisters are frequent side effects.   

Scar Revision

Indications for scar revision

Long, linear, and out of alignment with RSTL; Webbed; Pin-cushioned; Widened; Perpendicular to RSTL.
Hypertrophied; Nearby but not located in a favorable location.
Distorting anatomical functions and facial traits.

Available Techniques

Excision: The scar is completely removed, and fresh sutures are put in place.  Expansion: When you remove tissue, the surrounding tissue becomes larger.  Irregularization: Z and W plasty procedures are possible.  Abrasion: It is possible to perform microdermabrasion.  Anabolic

Emerging Therapies

For hypertrophic scars, 5-FU and an interferon injection are options.

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