Here we report the case of a 53-year old male patient, who underwent mitral valve replacement and coronary artery bypass surgery(LIMA to LADA) on April 16, 2019. He was a known case of diabetes and chronic obstructive pulmonary disease (COPD). Five weeks after surgery, the patient was referred to our center with a 1-week history of abundant discharge accompanied by fever(39.5℃),painful sternal instability, and shortness of breath. He had a purulent wound in the upper part of his sternotomy incision, with a fistula approximately 4cm long(Fig. 1A). A computed tomography (CT) scan of the thorax conducted in response showed sternal non-union up to 7 mm wide(Fig. 1B). Inflammatory markers were significant with a white blood cell count of 19.5×109/L and an erythrocyte sedimentation rate(ESR) of 77 mm/H. A C-reactive protein(CRP) level was 105.9 mg/L. Serum albumin and hemoglobin were 28 g/L and 85 g/L, respectively. The wound culture examination revealed vancomycin-sensitive enterococcus cloacae. DSWI with sternal dehiscence was the diagnosis. An operation was scheduled immediately because of severe infection symptoms on May 28, 2019. General anesthesia was administered to this patient prior to surgery. The surgical technique was divided in two stages. Stage I: 1) aggressive debridement was performed on this patient. All abnormally proliferated granulation tissue and residual foreign bodies were removed. Then, the wound was rinsed repeatedly with hydrogen peroxide, iodophor, and normal saline(Fig. 1C). 2) Antibiotic impregnated cement (PALACOS MV®+G bone cement༌Heraeus, Heraeus Medical GmbH, Wehrheim, Germany ) was prepared by combining a 40 g bag of cement with 2 g of vancomycin. The sternal defect was filled with an appropriate amount of ALBC༌which provided a reliable bone coverage(Fig. 1D). Aslo, the holes were made on the surface of ALBC for drainage. 4) Next, bilateral pectoralis major muscle flaps and subcutaneous tissue were raised off, from the chest wall to adistance of about 4 cm from incision margin (Fig. 1E). Furthermore, the drainage tube was placed between ALBC and the subcutaneous layer. And then, the skin was relaxedly sutured without significant tension(Fig. 1F). Finally, the skin around the wound was cleaned with 75% alcohol and a semipermeable membrane was used to seal the wound and the VSD dressing(Fig. 1G), the negative pressure is -75 mmHg to -100 mmHg. One week postoperatively, VSD device was removed. The drainage-fluid culture (tested twice), ESR, and CRP were normal after 10 days of intravenous vancomycin antibiotics therapy. The thoracic cage was stable and he was symptom-free(Fig. 1H).
Two months after the stage I surgery procedure,our final step was removing the previous ALBC(Fig. 2A), and extensive debridement in stageII. The second re-exploration revealed a clean, red, granulating wound bed was achieved(Fig. 2B). Subsequently, the bilateral pectoralis major muscle flap were mobilized from the thorax wall again(Fig. 2C-2D). The subcutaneous tissue and bilateral pectoralis major muscle flap were intermittently sutured to cover sternum defect by methods of relieving tension and no residual foreign bodies(Fig. 2E). Furthermore, two drain tubes were placed: one under the muscle flap and the other under the subcutaneous layer(Fig. 2F). Sutures were removed 14 days after the operation and this patient was discharged in good local and general condition on August 17, 2019, 20 days after the stage II surgery. Drainage tubes were removed when output was less than 5 ml/d for 3 days. Three months postoperatively, the skin healed nicely(Fig. 2I), and three-dimensional rib reconstruction revealed sternal dehiscence as before(Fig. 2G). A final CT scan documented scar tissue covering the mediastinum(Fig. 2H). More than 1 years after this surgery, the patient did not relapse.