Botulinum Toxin Type a Injection to Prevent Keloid Recurrence

After the whole surgical procedures of keloid revision are done, the participants will receive Botulinum Toxin type A (BTA) injection. The investigators split the scar into the right side and the left side. BTA and 0.9% saline, respectively, are used for the two arms of the study. Vials containing 100 units of BTA (BotoxⓇ, Allergan) are mixed with 2mL 0.9% injectable saline. The injection depth will be the intradermal layer. Injections will be performed with a 30-gauge needle and 1 mL syringe. Just before skin closure, the entire scar was treated, with sides randomized to receive treatment with either BTA or 0.9% normal saline. The dosage is 8 units / cm based on aforementioned studies. The maximal dose won't exceed 100 units.

After the whole surgical procedures of keloid revision are done, the participants will receive 0.9% saline injection. The investigators split the scar into the right side and the left side. BTA and 0.9% saline, respectively, are used for the two arms of the study. Only 0.9% saline is injected on the control side. The injection depth will be the intradermal layer. Injections will be performed with a 30-gauge needle and 1 mL syringe. Just before skin closure, the entire scar was injected, with sides randomized to receive treatment with either BTA or 0.9% normal saline. The dosage is 0.16 mL / cm.