Scientific Studies

Alster T, Tanzi E. The Washington Institute of Dermatologic Laser Surgery, Washington, USA.

Keloid and hypertrophic scars have affected patients and frustrated physicians for centuries. Keloid and hypertrophic scars result from excessive collagen deposition, the cause of which remains elusive. Clinically, these scars can be disfiguring functionally, aesthetically, or both. A thorough understanding of the pathophysiology and clinical nature of the scar can help define the most appropriate treatment strategy. Although many articles have been published on the management of hypertrophic and keloid scars, there is no universally accepted treatment protocol. Prevention of keloid and hypertrophic scars remains the best strategy; therefore, those patients with a predisposition to develop excessive scar formation should avoid nonessential surgery. Once a scar is present, there are many treatments from which to choose. Hypertrophic scars and keloids have been shown to respond to radiation, pressure therapy, cryotherapy, intralesional injections of corticosteroid, interferon and fluorouracil, topical silicone or other dressings, and pulsed-dye laser treatment. Simple surgical excision is usually followed by recurrence unless adjunct therapies are employed. Biologic agents that are directed towards the aberrant collagen proliferation that characterizes keloid and hypertrophic scars might be an important addition to the current armamentarium of modalities in the near future.

Am J Clin Dermatol. 2003;4(4):235-43.

Ahn ST, Monafo WW, Mustoe TA.
Department of Surgery, Washington University School of Medicine, St Louis, Mo 63110.

We studied the effects of a silicone gel bandage that was worn for at least 12 hours daily on the resolution of hypertrophic burn scar. In a second cohort, the prevention of hypertrophic scar formation in fresh surgical incisions by this bandage was also evaluated. In 19 patients with hypertrophic burn scars, elasticity of the scars was quantitated serially with the use of an elastometer. An adjacent or mirror-image hypertrophic burn scar served as a control. Scar elasticity was increased after both 1 and 2 months compared with that in controls. There was corresponding improvement clinically that persisted for at least 6 months. In the other cohort, scar volume changes in 21 surgical incisions were measured before and after 1 and 2 months. Gel-treated incisions gained less volume than control incisions after both intervals. Clinical assessment corroborated this quantitative demonstration of a decrement in scar volume. We concluded that topical silicone gel is efficacious, both in the prevention and in the treatment of hypertrophic scar.

Arch Surg. 1991 Apr;126(4):499-504..

Gold MH, Foster TD, Adair MA, Burlison K, Lewis T.

Gold Skin Care Center, Nashville, Tennessee 37215, USA.

BACKGROUND: Topical silicone gel sheeting has been used for more than 20 years to help reduce the size of hypertrophic scars and keloids. Its clinical efficacy and safety is well established. OBJECTIVE: To determine whether topical silicone gel sheeting can be used to prevent hypertrophic scars and keloids from forming following dermatologic skin surgery. METHODS: Patients undergoing skin surgery were stratified into two groups: those with no history of abnormal scarring (low-risk group) and those with a history of abnormal scarring (high-risk group). Following the procedure, patients within each group were randomized to receive either routine postoperative care or topical silicone gel sheeting (48 hours after surgery). Patients were followed for 6 months. RESULTS: In the low-risk group, there were no statistical differences between individuals using routine postoperative care or using topical silicone gel sheets. In the high-risk group, there was a statistical difference (39% versus 71%) between patients who did not develop abnormal scars and used topical silicone gel sheeting and patients who developed abnormal scars after routine postoperative treatment. Those individuals having a scar revision procedure also showed a statistical difference if topical silicone gel sheeting was used following surgery. CONCLUSION: Topical silicone gel sheeting, with a 20-year history of satisfaction in dermatology, now appears to be useful in the prevention of hypertrophic scars and keloids in patients undergoing scar revision.

Dermatol Surg. 2001 Jul;27(7):641-4.

Fulton JE Jr. Institute for Skin Research, Newport Beach, California 92660, USA.

BACKGROUND. Hypertrophic scars and keloids remain a problem for surgeons. Topical and intralesional corticosteroids, positive pressure dressings, cryotherapy, and laser therapy are helpful but not uniformly successful. OBJECTIVE. To document the effectiveness of silicone gel sheeting in the prevention and/or reduction of evolving hypertrophic scars and keloids. METHODS. Silicone gel sheeting was placed over evolving scars in 20 cases. The dressing was worn for at least 12 hours a day. Biopsies were examined for the presence of silica in the tissue. RESULTS. Lesions improved during the treatment period in 85% of the cases. The mechanisms of action are unknown. Positive pressure was not necessary. No silica from the dressing was found at the wound site. CONCLUSION. Daily treatments with silicone gel sheeting should begin as soon as an itchy red streak develops in a maturing wound. The dressing is effective in reducing the bulk of these lesions.

Dermatol Surg 1995 Nov;21(11):947-51.

Kuhn MA, Moffit MR, Smith PD, Lyle WG, Ko F, Meltzer DD, Robson MC.

Institute for Tissue Regeneration, Repair and Rehabilitation, Department of Veterans Affairs Medical Center, Bay Pines, FL 33744, USA.

BACKGROUND: Fibroproliferative disorders, which include hypertrophic scars and keloids, represent deviations from the normal process of wound healing. The fibrogenic cytokines have been associated with excessive scarring. It has been proposed that placing silicone in contact with hypertrophic scars may prove to be an effective form of treatment. This may be a result of downregulating fibroblasts and/or decreasing the fibrogenic cytokines. An in vitro model to study wound contraction is a fibroblast populated collagen lattice (FPCL). This study used FPCL as a method to study the effect of silicone sheeting on hypertrophic scar fibroblasts. METHODS: Fibroblast cultures were obtained and collagen lattices were prepared. Silicone sheeting was placed over the collagen matrix versus Saran wrap used as a treatment control. The amount of gel contraction was measured every 24 hours for five days. The supernatant obtained from the culture medium following completion of the FPCL portion of the experiment was then used in an immunoassay for TGFbeta2. RESULTS: A statistically significant decrease in amount of FPCL contraction occurred between three of the four brands of silicone sheets used compared to untreated control or Saran wrap treated FPCL. The immunoassay for TGFbeta2 showed a statistically significant decrease with all four types of silicone sheeting. CONCLUSION: FPCLs populated with burn hypertrophic scar fibroblasts exposed to silicone sheeting have decreased contraction compared to an unexposed control and Saran wrap treated control. In addition, TGFbeta2 is downregulated in the silicone exposed group. It appears that silicone sheeting may act by downregulating fibroblasts and decreasing fibrogenic cytokines.

Int J Surg Investig. 2001;2(6):467-74.

R. James Koch, MD

Wound Healing and Tissue Engineering Laboratory, Division of Otolaryngology/Head and Neck Surgery, Stanford University Medical Center, Stanford, California

Abstract

Topical silicone gel has shown promise in the treatment of hypertrophic and keloid scars. Fibroblast specimens were cultured in serum-free media and exposed to silicone gel. Serial cell counts were performed and supernatants were collected for bFGF quantification by enzyme-linked immunosorbant assay (ELISA) at 24, 72, and 120 hours.

Statistically significant differences were observed in bFGF levels between treated and untreated normal fibroblasts were observed at 24, 72, and 120 hours after cell culture initiation.

These results suggest that silicone gel is responsible for increased bFGF levels in dermal fibroblasts. We postulate that silicone gel treats and prevents hypertrophic scar tissue, which contains histologically normal fibroblasts by modulating expression of growth factors such as bFGF.

Kin Yoong Chan, M.R. C.S. Ed., Chee Lan Lu, B. Sc. Pharm., Syed Mohd Adeeb, MS, Sathappan Somsaundaram, F.R.C.S., and Mohd Nasari-Zahari, F.R.C.S. Kuala Lumpur, Malaysia

Background: Hypertrophic scarring caused by sternotomy is prevalent among Asians. The effectiveness of silicone gel in scar prevention pay influence the decision of surgeons and patients regarding its routine use during the postoperative period.

Methods: The authors conducted a randomized, placebo-controlled, double-blind, prospective clinical trial. The susceptibility to scar development varied among patient; therefore, sternal would were divided into the upper half and lower half. Two types of coded gel prepared by an independent pharmacist were used on either half. Thus, selection and assessment biases and confounders were eliminated. Results: One hundred wounds in 50 patients were randomized into two arms, patients control and 50 silicone gels. The median age was 61 years and there were 35 men and 16 women. Ethnic distribution was 28 Malays, 18 Chinese and four Indians. No side effect caused by the silicone gel was noted. Ninety-eight percent of patients had moderate to good compliance. The incidence of sternotomy scar was 94 percent. At the third month postoperatively, the silicone gel wounds were scored lower when compared with the control wounds. The differences were statistically significant in all parameters, including pigmentation (p= 0.20), vascularity (p= 0.001), pliability (p= 0.001), height (p= 0.001), pain (p= 0.001), and itchiness (p= 0.02). Conclusions: The effect of silicone gel in prevention of hypertrophic scar development in sternotomy wounds is promising. There are no side effects and patients’ compliance is satisfactory. This study may popularize the use of silicone gel in all types of surgery to minimize the formation of hypertrophic scars in the early postoperative period. (Plast. Reconstr. Surg. 116: 1013, 2005.)

Massimo Sinorini, M.D., and Matteo Tretti Clementoni, M.D.

Instituto Dermatologico Europeo, Milano, Italy

Abstract: Topical silicone gel sheeting and intralesional steroids are the only evidence-based recommendable forms of treatment to control the quality of a scar.  The advantages and disadvantages of both are well known.  This study was undertaken to verify the efficacy of a new topical silicone treatment:  a self-drying spreadable gel that needs no means of fixation and cannot be seen because of complete transparency.  Fresh surgical scars treated with the tested product showed significantly better outcomes than those untreated in a prospective trial involving a group of 160 patients.  Patient compliance was particularly good, especially for scars on exposed areas such as the face, where the traditional gel sheeting is frequently discontinued at an early stage by patients who object to its visibility.  The results of the self-drying silicone gel have indeed been satisfactory.  Considering the effective results obtained and the good patient compliance, the authors currently rate this concept of treatment as the first choice for preventing hypertrophy of recent scars.

Aesth. Plast. Surg. 31:183-187, 2007

Berman B, Perez OA, Konda S, Kohut BE, Viera MH, Delgado S, Zell D, Li Q.

Source

Department of Dermatology and Cutaneous Surgery, University of Miami, Miller School of Medicine, Miami, Florida, USA.

Abstract

Silicone elastomer sheeting is a medical device used to prevent the development of and improve the appearance and feel of hypertrophic and keloid scars. The precise mechanism of action of silicone elastomer sheeting has not been defined, but clinical trials report that this device is safe and effective for the treatment and prevention of hypertrophic and keloid scars if worn over the scar for 12 to 24 hours per day for at least 2 to 3 months. Some of the silicone elastomer sheeting products currently on the market are durable and adhere well to the skin. These products are an attractive treatment option because of their ease of use and low risk of adverse effects compared to other treatments, such as surgical excision, intralesional corticosteroid injections, pressure therapy, radiation, laser treatment, and cryotherapy. Additional controlled clinical trials with large patient populations may provide further evidence for the efficacy of silicone elastomer sheeting in the treatment and prevention of hypertrophic and keloid scars. The purpose of this article is to review the literature on silicone elastomer sheeting products and to discuss their clinical application in the treatment and prevention of hypertrophic and keloid scars.