Objective: To study the efficacy of 10% onion extract in silicone derivative gel for the prevention of hypertrophic scar and keloid in median sternotomy wound from open heart surgery in pediatric patients.

Material and Method: Thirty-nine pediatric patients who had median sternotomy were recruited in this prospective randomized, double-blinded, placebo-controlled split-scar experimental study. The wound in each patient was divided into upper and lower parts, and the treatment with, either onion extract gel or placebo was randomly applied by block randomization onto each part of the wound twice daily after the seventh day postoperatively for six months. The incidence of scars, serial photographs of the wound, Vancouver Scar Scale (VSS), and adverse effect were assessed at each visit.

Results: Thirty patients with the mean age of 4.3 years completed the 6-month study period. Six patients (20%) in onion extract gel group had no scar compared to one patient (3.3%) in placebo group (p = 0.04). Of the 27 patients with hypertrophic scar, nine were from onion extract gel group and 18 from the placebo group (p = 0.02). Keloid was not statistically significant different in both groups (p = 0.29). VSS was not statistically significant different in all visits. One case had a pustule on the part of the onion extract in silicone derivative application at the sixth month.

Conclusion: Onion extract in silicone derivative gel can significantly decreased the incidence of hypertrophic scar from median sternotomy wound in pediatric patients. Keloid did not show statistically significant differences in both groups.

Keywords: Onion extract, Hypertrophic scar, Median sternotomy wound, Pediatric patients