**7. Reconstruction of sternal bone defect after DSWI in cardiac surgery**

Wire re-cerclage was a commonly used method for addressing sternal approximation in patients with sternal dehiscence after DSWI [72,86,102]. The quality of residual sternal bone or its loss makes re-cerclage troublesome or even risky for achieving sternal stability. The occurrence of extensive adhesions below the sternum in DSWI patients increases the risk of damage to the right ventricle and bypass grafts when peri-, trans- and parasternal wiring techniques are used [72,99,100]. Today, stable osteosynthesis of the sternum, particularly using transverse plates, has become a method of treatment of post-DSWI sternal dehiscence [76]. Voss at el reported an institutional experience with Titanium Sternal Fixation system™ plates for sternal non-union in 15 patients, in which four patients had more than two previous attempts to stabilize the chest with some modification of wire re-cerclage, and four patients were treated for DSWI with NPWT prior to plating. All patients were successfully stabilized and healed, with one patient from the DSWI group experiencing a late infection recurrence and one dying from a complication not related to plating [152]. Larger experience with the same plate system has been reported by Baillot et al in a group of 92 patients after DSWI [46]. They achieved chest stabilization in all cases, with 9 patients (9.8%) undergoing further procedure for late infection recurrence including removal of the plate with no impact on sternal stability [153]. Chest stability after a healed DSWI improves respiratory function, augments wound healing processes, shortens in-hospital stay, and improves patient quality [46,72,80]. Plating seems to be an effective method of chest wall stabilization, but may fail in cases of massive loss of chest bone tissue. In these cases, the bone residue does not allow sufficient anchoring for the plates or there is a large bone tissue gap. Shear forces may loosen screws and threaten stability. Persistent pain and respiratory discomfort were also reported in this case [154]. A conventional surgical approach to manage the large residual bone defect leaves the sternotomy wound unstable and employs the greater omentum or a muscle flap to fulfill any dead spaces [93,95,99,103]. This approach resulted in sternal instability and flap-related morbidity even when wounds were well-healed [154]. Some case reports have included the use of an autologous bone iliac crest graft or allogenous fibula graft to supply residual bone defects after DSWI [155,156]. Marulli reported the first use of an allogenous sternocostal bone graft for sternal reconstruction after chondrosarcoma removal [157]. Consequently, Dell'amore et al described four patients who were managed with the same technique with no wound healing complications and preserved chest wall stability [158]. The same authors proposed this technique for major post-DSWI defects, and [159] Kalab et al described the possibility of using an allogenous calva bone graft to address this issue. Allogenous bony grafts being fixed with transverse plates in mentioned cases [158-160]. Bone allograft usage for transplantation is under law restriction of local governments and European Association of Tissue Banks [161,162].

of recurrence; its low virulence, ability to create biofilm on metallic materials and inherent low sensitivity against prophylactically administrated antibiotics limit its eradication [41,143].

With the rise in use of NPWT came an increased number of reported serious bleeding com‐ plications [144,145]. The risk of heart injury, particularly the right ventricle, bypass grafts or great vessels is well known from conventionally treated patients. Infectious erosion, displace‐ ment of heart structures towards sternal margins, or tractions of fibrosis adhesion were identified as potential mechanism of injury [146]. The incidence of these complications by conventional therapy was found to be between 2-14.8% [147-149], with data from a larger group of NPWT treated patients showing 2 to 5%, thus NPWT does not seem to increase the incidence of serious complications [116,118,127,130,146,150]. Mortality from these complica‐ tions varies between 25 to 70%, with emergency surgery as well as proper covering of mediastinal structures with interface dressing being crucial for management [146-148,150]. Several layers of paraffin gauze or silicone mesh are usually put below sternal margins on the heart and grafts. Development towards more suitable material, particularly rigid barrier for mediastinal protection is in progress, including mediastinal protection and preserved drainage

**7. Reconstruction of sternal bone defect after DSWI in cardiac surgery**

Wire re-cerclage was a commonly used method for addressing sternal approximation in patients with sternal dehiscence after DSWI [72,86,102]. The quality of residual sternal bone or its loss makes re-cerclage troublesome or even risky for achieving sternal stability. The occurrence of extensive adhesions below the sternum in DSWI patients increases the risk of damage to the right ventricle and bypass grafts when peri-, trans- and parasternal wiring techniques are used [72,99,100]. Today, stable osteosynthesis of the sternum, particularly using transverse plates, has become a method of treatment of post-DSWI sternal dehiscence [76]. Voss at el reported an institutional experience with Titanium Sternal Fixation system™ plates for sternal non-union in 15 patients, in which four patients had more than two previous attempts to stabilize the chest with some modification of wire re-cerclage, and four patients were treated for DSWI with NPWT prior to plating. All patients were successfully stabilized and healed, with one patient from the DSWI group experiencing a late infection recurrence and one dying from a complication not related to plating [152]. Larger experience with the same plate system has been reported by Baillot et al in a group of 92 patients after DSWI [46]. They achieved chest stabilization in all cases, with 9 patients (9.8%) undergoing further procedure for late infection recurrence including removal of the plate with no impact on sternal stability [153]. Chest stability after a healed DSWI improves respiratory function, augments wound healing processes, shortens in-hospital stay, and improves patient quality [46,72,80]. Plating seems to be an effective method of chest wall stabilization, but may fail in cases of massive loss of chest bone tissue. In these cases, the bone residue does not allow sufficient anchoring for the plates or there is a large bone tissue gap. Shear forces may loosen screws and threaten stability. Persistent pain and respiratory discomfort were also reported in this case [154]. A conventional surgical approach to manage the large residual bone defect leaves the

ability of therapy [151].

506 Artery Bypass
