Background: Hypertrophic scar development after median sternotomy wound in cardiac surgery patients is quite common in surgical practice and becomes a major concern nowadays.
Objective: To compare cosmetic outcome between different suture materials and different suture techniques for skin closure in median sternotomy wound.
Material and Method: A randomized clinical trial was conducted in 80 patients who underwent cardiac surgery in Thammasat University Hospital, Thailand. In respect of the materials and the techniques used to suture the skin, the patients were randomly allocated to four groups. In group 1, the skin was closed with subcuticular running 4-0 Poliglecaprone 25 (Monocryl). In group 2, the skin was closed with subcuticular running 4-0 Polydioxanone (PDS). In group 3, the skin was closed with subcuticular running 4-0 Poliglecaprone 25 (Monocryl) and running horizontal mattress 6-0 Nylon. In group 4, the skin was closed with subcuticular running 4-0 Polydioxanone (PDS) and running horizontal mattress 6-0 Nylon. Postoperative evaluation was performed at 2 and 6 weeks, 3 and 6 months follow-up visits. The scar was analyzed in three parts: upper, middle and lower one third of the sternal wound. The outcome measures for surgical wound were width, height and overall appearance of the scar using the Vancouver scar scale (VSS). A linear visual analogue score (VAS) was preformed to assess pain and itch.
Results: At 6 months, there were no significant differences between 4 groups of patients in every parameters (width, height, VSS, pain score and itch score) at three different wound sites (upper, middle and lower). There was a statistically significant and progressive increase in scar stretching, height and total VSS from top to bottom of the sternum with the same pattern in all groups of patients (p<0.05). At 6 months, scar showed a statistically significant difference in width when compares to 6 weeks and 3 months (p<0.001).Female had a statistically significant difference of scar stretching at upper two third of the sternum (p<0.05). Female scar width was approximately 2 folds greater than male patient. During follow-up in group 3, two patients died postoperatively due to multi-organ failure and one patient developed wound infection.
Conclusion: There were no significant differences in cosmetic outcomes between different suture materials and different suture techniques.

Keywords: Polydioxanone, Poligiecaprone 25, Running horizontal mattress, Hypertrophic scar development, Median
sternotomy wound