Silicone gel sheeting (SGS) has been an effective reduction and preventive scar therapy since 1980. [1] It was first discovered to be used in treating scars by Perkins in Australia and New Zealand, and first discussed in the thesis of Karen Quinn, a British biomedical engineering student, in 1985. [2]
It is now considered the first-line prevention and treatment for hypertrophic and keloid scars by occlusion and then hydration of the scar tissue. [3] Silicone gel is made of medical-grade silicone polymers. [4] Silicone gel sheet consists of a soft, semi-occlusive sheet and a membrane that increases the durability of the sheet. [3] The sheet has a solid rubber-like appearance.
Although the mechanism of action of silicone gel sheeting remains partially unknown, its efficacy is confirmed by many clinical trials, [5] and is similar to silicone gel. [6]
Silicone gel sheeting is the gold-standard and non-invasive treatment for hypertrophic and keloid scars. During skin injury repair, dermal cells proliferate and migrate from the skin tissue to the wound, producing collagen and causing contraction of the placement dermis. [5] These scars are proliferative due to chronic inflammation and overproduction of abnormal collagen. [7] Common clinical presentations of these scars are raised, thickened, red, or dark-colored. [4] Patients may also experience pain and itching. [8]
Hypertrophic scars are elevated scars that remain in the region of the original lesion [9] following mechanical traumas, burns, and necrotizing infections. [10] These scars typically develop in locations under tension, such as shoulders, ankles, knees, and the neck. [8] Hypertrophic scars are generally confined to the boundaries of the original wound and tend to diminish over time. [11]
Keloids grow extensively beyond the wound margins and tend to persist or even worsen over time. [11] They are relatively difficult to treat due to their high risk of recurrence. [9] Keloids are more common in people with darker skin tones [12] and often occur in individuals with a genetic predisposition. [13] Keloids are the most extreme type of scarring since minor wounds such as insect bites or piercings can all lead to an elevated tissue area. Patients may experience psychological trauma if their scars are not well-controlled. [8] Therefore, the prevention of wound formation is crucial to them. They should avoid undergoing any unnecessary invasive procedures or cosmetic surgeries. [14]
The beneficial effects of silicone gel sheeting on the treatment and prevention of these two scars have been confirmed. [10] Since most patients develop hypertrophic and keloid scars within 3 months after surgery or injury, the silicone gel sheeting therapy should be started in the early repair phase to achieve an optimal therapeutic effect. The maturity of scars takes over a year; therefore, silicone treatment is also effective in scars aged over 12 months. [15] The therapy usually requires 6 to 12 months of constant wear to achieve optimum results. Recent data suggest that the combination of silicone gel sheeting and pressure therapy can improve post-traumatic scar healing. [4]
The sheet should not be used on open wounds. [16] [17] The sheet is reusable with proper cleaning though it should be replaced when it starts to deteriorate. [16]
The exact mechanism of action of silicone gel sheeting has not been fully studied. Currently, many proposed mechanisms explain the efficacy of such treatment, including the occlusion and hydration effect, increased body surface temperature, polarized electric charge, immunological effects, etc. [9] The occlusion and hydration effect is the most studied mechanism of action.
Silicone gel sheets occlude and hydrate the stratum corneum of the treated skin area. The stratum corneum normally conserves water and acts as a barrier to microbial infection. Its function can be disrupted by wound formation. The stratum corneum of hypertrophic scars and keloids absorbs more water than normal skin, depleting the water supply from the stratum corneum. Excessive dehydration of keratinocytes stimulates cytokine production, leading to increased collagen production. [18] [5] After applying the sheet, the rate of water loss via evaporation of the treated skin area is half of the untreated area. Therefore, the sheet prevents the drying up of stratum corneum, and thus further collagen production. Collagen production exacerbates the growth of hypertrophic scars and keloids and thus should be avoided. [9] [5] Hydrating a scar over a prolonged period can also relieve symptoms such as itching and pain. Such an effect is likely due to decreased capillary activity and thus local collagen deposition. [9]
Applying silicone gel sheeting causes a slight increase in surface temperature. Increased temperature intensifies the activity of collagenase, an enzyme that breaks down collagen. Since excessive collagen production leads to scar formation, increased levels of collagenase may help reduce the risk of scar formation. [9]
Silicone-related products can reduce the growth factor production of fibroblasts in hypertrophic scars and keloids. [19] However, the relevance is unclear as silicone products do not have direct contact with dermal fibroblasts but with the epidermis only. Possible relevance may be due to the initiation of a signaling cascade by the epidermis. Through the signaling cascade, the epidermis regulates dermal fibroblast extracellular matrix production. Delayed epithelialization, which raises the risk of hypertrophic scar formation, is less likely to happen. [18]
A negative static electric charge is formed by friction between the silicone gel sheet and the skin. The charge induces collagen realignment, aiding the elimination of the scar. [18] Moreover, the negative electric field leads to the polarization of scar tissues and thus scar shrinkage. [9]
Silicone gel sheeting has remained the first-line therapy stated by international clinical recommendations on scar management. [5]
Scar measurements studied in most clinical trials include color (vascularisation and pigmentation), thickness (height: clinical and histological), relief (surface irregularities), pliability (tissue elasticity), and surface area (scar contraction or expansion). [20]
Scar elevation index is commonly used to indicate scar improvement. It measures the height of scar tissue compared to the normal surrounding skin. [21] Studies show the effectiveness of silicone gel sheeting in minimizing scar elevation index. [22] Another physical measure is the pliability of the scar tissue, which is also improved by silicone gel sheeting. [23] Scar improvement is generally measured by size reduction, appearance, and calming effect. Silicone gel sheeting addresses the 3 requirements well among scar treatments. [5] Several randomized controlled trials were carried out to assess the effectiveness. Silicone gel sheeting produces a statistically significant reduction in scar thickness and color amelioration. Therefore, it is an evidence-based non-invasive preventive treatment. [24]
Results of comparative studies on the effectiveness of silicone gel sheeting and silicone gel do not show significant differences between the two. [25]
Another non-invasive treatment is compression therapy, in which patients wear pressure garments to control the growth of scars. Pressure garments apply mechanical pressure to the surface of the scar, reducing the supply of blood and oxygen to the scar tissue. Formation of excessive scar tissue is thus prevented. The combination of silicone gel sheeting and compression therapy has been proven to be more effective than using the sheet alone. [26]
Patients who find the non-invasive treatments ineffective may choose to undergo invasive treatments such as intralesional injections of corticosteroids, surgical excision of the scars, and radiotherapy. [26] [27]
Common side effects of silicone gel sheets include itchiness, rash, maceration of the skin, and malodor. [28] These symptoms are generally well-tolerated and can be minimized by rinsing the area properly daily. Patients who suffer from these side effects should wash the treated area and the silicone gel sheets with mild soap since the dirt or bacteria on the sheets may irritate the scar. [16] In tropical climates with high humidity, excessive moisture underneath the gel may lead to heat rash and uncomfortable sensations in patients. [2]
Silicone gel sheets are usually made of medical silicone polymers such as polysiloxane and polydimethylsiloxane, along with silicon dioxide and volatile components. The long-chain silicone polymers form cross-linking with silicon dioxide and spread as a thin sheet. [8]
They are either flesh color (most common) or clear and come as either a single large rectangle sheet or a roll. Available size varies with brands.
A scar is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in some degree of scarring. An exception to this are animals with complete regeneration, which regrow tissue without scar formation.
Keloid, also known as keloid disorder and keloidal scar, is the formation of a type of scar which, depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen. It is a result of an overgrowth of granulation tissue at the site of a healed skin injury which is then slowly replaced by collagen type I. Keloids are firm, rubbery lesions or shiny, fibrous nodules, and can vary from pink to the color of the person's skin or red to dark brown in color. A keloid scar is benign and not contagious, but sometimes accompanied by severe itchiness, pain, and changes in texture. In severe cases, it can affect movement of skin. In the United States, keloid scars are seen 15 times more frequently in people of sub-Saharan African descent than in people of European descent. There is a higher tendency to develop a keloid among those with a family history of keloids and people between the ages of 10 and 30 years.
A plantar wart is a wart occurring on the bottom of the foot or toes. Its color is typically similar to that of the skin. Small black dots often occur on the surface. One or more may occur in an area. They may result in pain with pressure such that walking is difficult.
Wound healing refers to a living organism's replacement of destroyed or damaged tissue by newly produced tissue.
Breast augmentation and augmentation mammoplasty is a cosmetic surgery technique using breast-implants and fat-graft mammoplasty techniques to increase the size, change the shape, and alter the texture of the breasts. Although in some cases augmentation mammoplasty is applied to correct congenital defects of the breasts and the chest wall in other cases it is used purely as a cosmetic surgery, primary breast augmentation changes the aesthetics – of size, shape, and texture – of healthy breasts.
Fibrosis, also known as fibrotic scarring, is a pathological wound healing in which connective tissue replaces normal parenchymal tissue to the extent that it goes unchecked, leading to considerable tissue remodelling and the formation of permanent scar tissue.
A hypertrophic scar is a cutaneous condition characterized by deposits of excessive amounts of collagen which gives rise to a raised scar, but not to the degree observed with keloids. Like keloids, they form most often at the sites of pimples, body piercings, cuts and burns. They often contain nerves and blood vessels. They generally develop after thermal or traumatic injury that involves the deep layers of the dermis and express high levels of TGF-β.
A dressing or compress is piece of material such as a pad applied to a wound to promote healing and protect the wound from further harm. A dressing is designed to be in direct contact with the wound, as distinguished from a bandage, which is most often used to hold a dressing in place. Modern dressings are sterile.
A breast implant is a prosthesis used to change the size, shape, and contour of a person's breast. In reconstructive plastic surgery, breast implants can be placed to restore a natural looking breast following a mastectomy, to correct congenital defects and deformities of the chest wall or, cosmetically, to enlarge the appearance of the breast through breast augmentation surgery.
In pathology, a contracture is a shortening of muscles, tendons, skin, and nearby soft tissues that causes the joints to shorten and become very stiff, preventing normal movement. A contracture is usually permanent, but less commonly can be temporary, or resolve over time but reoccur later in life.
A myofibroblast is a cell phenotype that was first described as being in a state between a fibroblast and a smooth muscle cell.
Artificial skin is a collagen scaffold that induces regeneration of skin in mammals such as humans. The term was used in the late 1970s and early 1980s to describe a new treatment for massive burns. It was later discovered that treatment of deep skin wounds in adult animals and humans with this scaffold induces regeneration of the dermis. It has been developed commercially under the name Integra and is used in massively burned patients, during plastic surgery of the skin, and in treatment of chronic skin wounds.
Burn scar contracture is the tightening of the skin after a second or third degree burn. When skin is burned, the surrounding skin begins to pull together, resulting in a contracture. It needs to be treated as soon as possible because the scar can result in restriction of movement around the injured area. This is mediated by myofibroblasts.
Non-surgical rhinoplasty is a medical aesthetic procedure in which injectable fillers, most commonly hyaluronic acid ones like Restylane and Juvederm or calcium hydroxyapatite (Radiesse), are used to alter and shape a person's nose without a surgery. The procedure fills in depressed areas on the nose, lifting the angle of the tip or smoothing the appearance of bumps on the bridge. Non surgical rhinoplasty is an augmentation procedure, so it cannot reduce the size of someone's nose. The cosmetic procedure carries the risk of causing serious skin damage or distant complications like blindness. If the filler product is injected into an artery, filler can travel in the arteries and blocks smaller size arteries like ophthalmic artery and cause blindness. If blood vessels of the skin is blocked, skin necrosis can develop. Hyaluronic acid based fillers can be reversed even if injected into a blood vessel with an enzyme called hyaluronidase, which can be also injected like fillers.
Plasma needling is a minimally invasive aesthetic medical procedure purported to rejuvenate skin, minimize the appearance of hypertrophic and hypotrophic scars and stretchmarks, and reduce pattern hair loss through multimodal physical and biochemical cellular stimulation. It is a combination of classical medical micro-needling by Dermaroller or DermaPen. Both are used in Collagen induction therapy and PRP. The latter is used in Prolotherapy as well as in the Vampire facelift. The effects on fibroblasts, cells, and micro-needling stem cells are published in scientific publications regarding micro-needling, and the injection of PRP, has also been tested as a combined treatment.
Scar free healing is the process by which significant injuries can heal without permanent damage to the tissue the injury has affected. In most healing, scars form due to the fibrosis and wound contraction, however in scar free healing, tissue is completely regenerated. During the 1990s, published research on the subject increased; it is a relatively recent term in the literature. Scar free healing occurs in foetal life but the ability progressively diminishes into adulthood. In other animals such as amphibians, however, tissue regeneration occurs, for example as skin regeneration in the adult axolotl.
Hydrogels are three-dimensional networks consisting of chemically or physically cross-linked hydrophilic polymers. The insoluble hydrophilic structures absorb polar wound exudates and allow oxygen diffusion at the wound bed to accelerate healing. Hydrogel dressings can be designed to prevent bacterial infection, retain moisture, promote optimum adhesion to tissues, and satisfy the basic requirements of biocompatibility. Hydrogel dressings can also be designed to respond to changes in the microenvironment at the wound bed. Hydrogel dressings should promote an appropriate microenvironment for angiogenesis, recruitment of fibroblasts, and cellular proliferation.
Topical cream formulation is an emulsion semisolid dosage form that is used for skin external application. Most of the topical cream formulations contain more than 20 per cent of water and volatiles and/or less than 50 per cent of hydrocarbons, waxes, or polyethylene glycols as the vehicle for external skin application. In a topical cream formulation, ingredients are dissolved or dispersed in either a water-in-oil (W/O) emulsion or an oil-in-water (O/W) emulsion. The topical cream formulation has a higher content of oily substance than gel, but a lower content of oily ingredient than ointment. Therefore, the viscosity of topical cream formulation lies between gel and ointment. The pharmacological effect of the topical cream formulation is confined to the skin surface or within the skin. Topical cream formulation penetrates through the skin by transcellular route, intercellular route, or trans-appendageal route. Topical cream formulation is used for a wide range of diseases and conditions, including atopic dermatitis (eczema), psoriasis, skin infection, acne, and wart. Excipients found in a topical cream formulation include thickeners, emulsifying agents, preservatives, antioxidants, and buffer agents. Steps required to manufacture a topical cream formulation include excipient dissolution, phase mixing, introduction of active substances, and homogenization of the product mixture.
Laser-assisted drug delivery (LADD) is a drug delivery technique commonly used in the dermatology field that involves lasers. As skin acts as a protective barrier to the environment, the absorption of topical products through the epidermis is limited; thus, different drug delivery modalities have been employed to improve the efficacy of these treatments. The use of lasers in LADD has been shown to enhance the penetration of drugs transdermal, leading to a higher absorption rate, limited systemic effects, and reduced duration of treatment. Although this technique has evolved in the past decade due to its efficacy through scientific research and clinical practice, there remain some limitations regarding the safety aspect that needs to be taken into consideration.
Microneedles (MNs) are medical tools used for microneedling, primarily in drug delivery, disease diagnosis, and collagen induction therapy. Known for their minimally invasive and precise nature, MNs consist of arrays of micro-sized needles ranging from 25μm to 2000μm. Although the concept of microneedling was first introduced in the 1970s, its popularity has surged due to its effectiveness in drug delivery and its cosmetic benefits.