Surgical technique
DSWI is defined as infection involving fascia or deeper with at least one of the following: evidence of infection seen at re-operation or spontaneous dehiscence, positive culture of mediastinal fluid and/or positive blood culture and/or chest pain with sternal instability and temperature higher than 38 degrees Celsius[7]. All patients with DSWI are well prepared preoperatively, including early wound exploration and drainage, antibiotic therapy, nutritional support and cardiopulmonary function.
All patients are anesthetized with tracheal intubation. The infected tissue is resected in full layer along the edge of the incision and all sternal wires are removed. Use a rongeur to remove the infected sternum until healthy solid bone with briskly bleeding margins is found. If the bone is obviously necrotic, the entire sternum is resected. Explore the posterior sternum space to thoroughly remove infected tissue and foreign materials, such as residual pacemaker wires. If infection involves extracardiac conduit and patch, they must also be removed.Mediastinal secretions and infected tissue are sent for culture. The wound is irrigated with hydrogen peroxide and normal saline.
According to the size of the wound defect decide whether unilateral or bilateral pectoralis major flap. If an unilateral pectoralis major flap is used, the right pectoralis major is usually chosen because muscles are more developed on this side. Dissect the overlying skin off the pectoralis major muscle from medial to the anterior axillary line.Cut off the muscle at the junction of medial 2/3 and the lateral 1/3 by using electrotome.Dissect the medial muscle from lateral to medial until the perforating vessels are visible. Flip muscles to fill the mediastinum as a turnover flap. The turnover muscle flap is fixed with double-stranded no.7 silk sutures by methods of relieving tension. The drainage tube is placed in the mediastinum. skin is closed with interrupted silk sutures.Postoperatively,chest wall is pressurized with elastic bandage. The drainage tube is left in place for 4-7 days based on the amount of drained fluid. Postoperative antibiotic therapy was performed for 2-3 weeks according to culture results.
Table 1 Preoperative characteristics of patients