To treat the depressed scars by injecting nanofat and investigate its therapeutic effect.

Autologous fat was harvested from abdomen or thigh using low-pressure suction. The lipoaspirate was mechanically emulsified after rinsing. Emulsification of the fat was achieved by shifting the fat between two 5 ml syringes connected to each other by a three direct connector. After this emulsification process, the fatty liquid was again filtered over the sterile nylon cloth. Nanofat was injected into the dermis of depressed scars using a 26-gauge needle and the injection volume was 1-2 ml/cm². After three months, another injection would be performed if the depressed scar remained obvious.

From January 2016 to October 2017, eighteen patients and thirty-three depressed scars were treated. There was a temporary erythema of the injected area that lasted two to three weeks. The clinical result gradually improved over time and were maximal from three months postoperatively for most cases. Three months after nanofat injecting, the cavity of scars was significantly decreased; The color of scars were significantly improved and more close to the adjacent skin; The stiffness of scars was also obvious decreased. The follow-up ranged 4 months to 18 months and the average was 11.0±4.6 months. Seventeen patients were satisfied with the result, one patients was not satisfied and the satisfaction rate was 94%. No infections, fat cysts, granulomas, or other unwanted side effects were observed.

Nanofat injecting is a definite and effective treatment for depressed scars with fewer complications.

Nanofat; Autograft; Depressed scar; Fat granule injection grafting