Discussion
Median sternotomy is the most frequently used incision for pediatric cardiac operation. However,DSWI after cardiac surgery is a severe complication that not only increases mortality and morbidity[9,10], but also prolongs hospital stays and increases treatment costs[11,12]. Risk factors for sternal wound infection in infant include low gestational age,prolonged ICU stay and open chest, cyanotic congenital heart diseases, high complexity of the surgical treatment, quality of the operative field treatment and surgical team experience[13-16].
The principles of treatment for DSWI are adequate debridement,removal of all infected tissue and foreign materials, a well-vascularized tissue transfer to promote wound healing, anterior mediastinal protection, and chest wall stability[3]. If the wound infection is suspected, early wound exploration and drainage are necessary, empirical broad spectrum intravenous antibiotics should be initiated. when culture results are available, targeted antibiotics should be used. once deep sternal infection is definite, surgical debridement should be performed as soon as possible. During debridement, the presence of residual foreign materials and infection involving implants should be carefully examined.In our study, 4 patients were found to have residual pacemaker wires and one patient was found to have infection involving the extracardiac conduit.we removed residual pacemaker wires,replaced the extracardiac conduit.
There is no consensus as to the best specific treatment for close the sternum after thorough surgical debridement.At present,the main treatment methods include sternal rewiring after debridement, Vacuum-assisted closure(VAC) therapy and flap reconstruction. For deep sternal wound infections, part of the sternum is often resected, resulting in unsatisfactory outcomes with the method of sternal rewiring. VAC can improve wound healing by increasing parasternal blood flow, reducing bacterial loads, enhancing formation of granulation tissue [17,18].But, using a vacuum system over an open sternum has raised concerns that the strong negative pressure could cause right ventricle rupture and other bleeding complications[19],and for sternum necrosis and severe infection, the failure rate of VAC is still high[20,21].
Currently, flap reconstruction is regarded as the gold standard in DSWI where there is inadequate sternum following debridement or uncertainty whether the infectious process has been controlled[22]. There has been a variety of flap choices for reconstructing sternal wounds, such as the pectoralis major flap, rectus abdominis flap and omental flap. The pectoralis major is a broad flat muscle that lies close to the sternum, allowing for easy dissection and providing adequate coverage. It has rich blood supply from thoracoacromial artery, segmental pedicles from the internal thoracic artery and some branches of the lateral thoracic and intercostals arteries. Based on the above advantages, pectoralis major muscle flap is the most commonly used flap and has achieved good results in adult patients [23].However, there are only a few reports about these techniques in pediatric patients.In this study, we used the pectoralis major muscle turnover flap technique. This technique preserves the lateral one third of the muscle with its dominant vascular pedicle and motor nerves, and preserves the contour of the chest wall, producing a better cosmetic result[24]. We consider the technique is easy and unilateral flap can completely fill stermal defect in most patients.It may be related to the relatively short sternum in infants. If unilateral flap does not completely close the defect, the residual sternal defect can be filled by splitting the opposite pectoralis major muscle turnover flap. Zahiri demonstrated the turnover flap to be associated with less postoperative complications when compared to the advanced pectoralis major flap[25]. Many studies suggest the use of VAC therapy to bridge definitive primary closure or flap reconstruction. However, we consider that immediate flap reconstruction after debridement may improve outcomes and shorter treatment time. In our study,all patients underwent one-stage debridement and flap reconstruction,and all of the sternal wounds healed successfully.
In pediatric patients, long-term development and limb function should be of special concern. During the follow-up,we found no evidence of any upper limb or upper trunk movements disorder,and chest walls were stable in all patients.Erez and colleagues [3] reported similar results in 5 neonates who were treated with unilateral PMMTF reconstruction. In female patients, the use of pectoralis major flap may have potential impact on breast development, should be long-term follow-up.
The study is subject to the usual limitations of a retrospective, uncontrolled study design. Our experience with pectoralis major turnover flap reconstruction over the past 10 years and have achieved good therapeutic results. Therefore, pectoralis major turnover flap reconstruction is our first choice for the treatment of DSWI. This is one of the reasons we did not have a control group. Another limitation of this study is the number of cases is small, so further large-scale controlled studies are needed.