Indications and Results of Sternal Allograft Transplantation: Learning From a Worldwide Experience.

BACKGROUND: Reconstruction of the anterior chest wall defect after sternectomy is a challenge for cardiothoracic surgeons. In 2010, the Padua group published the first case of cadaveric sternum transplantation after sternectomy. This multicenter study reports the clinical indications and early and long-term results of sternal chondral allograft transplantation. METHODS: This is a retrospective multicenter study from 7 academic centers. We collected demographic data, surgical indications, technical details, and early postoperative results. The complications, long-term stability, and tolerance of the allografts were also analyzed. RESULTS: Between January 2008 and December 2019, 58 patients underwent sternectomy followed by reconstruction using cadaveric-cryopreserved sternochondral allografts. Thirty-two patients were male, median age 63.5 years (interquartile range, 50-72 years). Indications for sternectomy were secondary sternal tumors (n = 13), primary sternal tumors (n = 15), and nonneoplastic disease (n = 30). Thirty patients underwent total sternectomy, 16 lower-body sternectomy, and 12 upper-body manubrium resection. The 30-day mortality was 5%; overall morbidity was 31%. Six early reoperations were necessary because of bleeding (n = 1), titanium plate dislocation (n = 1), and resuture of the skin in the lower part of the incision (n = 4). Overall, 5-year survival was 74%. In all the survived patients, the reconstructions were stable and free from mechanical or infective complications. CONCLUSIONS: The main indications for sternal allograft implantation were complex poststernotomy dehiscence followed by primary or secondary tumor involvement of the sternum. The collected results demonstrate that sternochondral allograft transplantation is a safe and effective method in reconstructing the anterior chest wall after sternectomy. Further studies to demonstrate the integration of the bone grafts into the patients' sternal wall will be made.

Failure of sternal wires depends on the number of turns and plastic deformation: combined experimental and computational approach.

OBJECTIVES: The number of turns at the end of a wire closure is not described or discussed in any cardiosurgical guidelines. The hands-on experience of the surgeon plays a significant role. The aim of this work was to clarify the relationship between the number of turns of the suture and the resulting strength of the sternal fixation. METHODS: The study was performed in 2 independent steps. The first step was a finite element simulation, where the stress and strain distribution of the sternal fixation was observed. The second step included the experimental set-up and the statistical evaluation of the results. RESULTS: Our study showed that the failure force rose linearly as the number of turns increased. The lowest average measured force was 370 N (3 turns); the highest was 430 N (7 turns). The failure modes were either untwisting of the wires or rupture of the closure, which is controlled by the number of turns. As the number of turns increases, superficial cracks can occur. CONCLUSIONS: Based on our results, the 5-turn option is the best solution for the closure. The failure force is still double the value reported in the literature, so there is a high safety margin for failure. The failure mode is untwisting; hence, no unexpected fracture can occur, and there is still an elastic core in the cross-section of the wire.

Reconstruction of massive post-sternotomy defects with allogeneic bone graft: four-year results and experience using the method.

OBJECTIVES: Deep sternal wound infection poses a serious problem in cardiac surgery, with an up to 40% risk of mortality. Massive loss of sternum bone tissue and adjacent ribs results in major chest wall instability causing respiratory insufficiency and defects of soft tissue healing. Proposals for managing the situation have been published but the complexity of the issue precludes unequivocal resolution. Capitalizing on orthopaedic experience, we used allogeneic bone graft of sternum as a viable option. METHODS: We performed the transplantation of allogeneic bone graft in 10 patients. In 9 cases, an allograft of sternum was used and in 1 case an allograft of calva bone. After the primary cardiac surgery, a massive post-sternotomy defect of the chest wall had developed in all 10 patients. Vacuum wound drainage was applied in the treatment of all patients. To stabilize the transverse, titanium plates were used. Bone allograft was prepared by the official Tissue Centre. Crushed allogeneic spongy bone was applied to reinforce the line of contact of the graft and the edges of residual skeleton. In 9 cases, the soft tissue was closed by direct suture of mobilized pectoral flaps. In 1 case, V-Y transposition of pectoral flap was performed. RESULTS: In 6 cases, healing of the reconstructed chest wall occurred without further complications. In 3 cases, additional re-suture of the soft tissues and skin in the lower pole of the wound was necessary. Excellent chest wall stability along with the adjustment of respiratory insufficiency and good cosmetic effect was achieved in all cases. In 1 case, severe concomitant complications and no healing of the wound resulted in death within 6 months after the reconstruction. Median follow-up of all patients in the series was 14.1 months (1-36 months). In 4 patients, scintigraphy of the chest wall was performed. CONCLUSIONS: Our existing results show that allogeneic bone graft transplantation is a promising and easily applied method in the management of serious tissue loss in sternal dehiscence with favourable functional and cosmetic effects. The relatively small number of patients with such severe healing complications of sternotomy however puts critical limits to a more detailed comparison with other practices and evaluation of long-term results.

Successful three-year outcome in a patient with allogenous sternal bone graft in the treatment of massive post-sternotomy defects.

INTRODUCTION: Deep sternal wound infection is a life-threatening complication of longitudinal median sternotomy with extensive loss of sternal bone tissue and adjacent ribs. Wound dehiscence cases with no loss of bone tissue can be resolved via osteosynthesis using titanium plates. Unfortunately, this cannot be used in cases of massive bone tissue loss defects due to insufficient support for fixing the plate material caused by missing bone surface which increasing the risk of osteosynthesis failure. We describe the treatment outcome of sternal dehiscence with massive bone tissue loss defects using an allogenous sternal bone graft. CASE PRESENTATION: A 62 year old diabetic female was operated for serious sternotomy dehiscence after surgery for aortic valve replacement. There was bone tissue loss and complications. We used allogenous sternal bone graft to close the wound. To monitor the healing of the graft, we performed SPECT/CT examinations of anterior chest wall. We describe the successful healing of the graft with the reduction of defects in osteoblastic activity by 42% 21 months after the graft implantation. The wound was found to be healed on all examinations, The chest wall is stable and the patient reports a good life quality. DISCUSSION: An allogenous bone transplant contains no vital bone marrow cells, which eliminates immuno-genetic graft rejection by the patient. Significant osteoblastic activity was thus registered, especially in places where crushed spongy bone had been applied. CONCLUSIONS: Transplantation of allogenous bone graft sternum in our experience is the best option for treating extensive post-sternotomy defects.

Pectoral muscle flap with V-Y skin paddle for covering sternal defects.

Deep sternal wound infection (DSWI) after a cardiac operation is a rare but serious complication associated with significant morbidity and mortality. It can lead to wound dehiscence with sternal osteomyelitis and both bony and soft tissue residual defects. When the infection is eradicated, reconstruction of the thoracic wall remains the main challenge. Tissue used for covering the defect must be well nourished and sutures must be tension free. We present our unique modification of the method using the pectoral muscle axial flap with a V-Y skin paddle.

Use of allogenous bone graft and osteosynthetic stabilization in treatment of massive post-sternotomy defects.

Thoracic stabilization using transverse plate fixation represents a modern and safe method of sternal dehiscence treatment. However, it still remains difficult to apply in cases of massive loss of bone tissue of the chest wall. An unsatisfactory stability of thorax often results in severe respiratory insufficiency, and also affects healing of soft tissue closure while increasing the risk of development of chronic fistulas and other dehiscences. In the reported case, we opted for a unique treatment of massive post-sternotomy defect using an allogenous bone graft of calva. Transverse titanium plates were applied to achieve stabilization of bone grafts and chest wall.

Vacuum-assisted closure in the treatment of sternal wound infection after cardiac surgery.

AIM: Vacuum-assisted closure (VAC) was primarily designed for the treatment of pressure ulcers or chronic, debilitating wounds. Recently, VAC has become an encouraging treatment modality for sternal wound infection after cardiac surgery, providing superior results to conventional treatment strategies. METHODS: From November 2004 to September 2006, 34 patients, undergoing VAC therapy for sternal wound infection following cardiac surgery, were prospectively evaluated. Ten patients (29 %) were treated for superficial sternal wound infection and 24 (71 %) for deep sternal wound infection. The median age was 69.9 years (range 48 to 82) and the median BMI was 33.4 kg/m(2) (range 28 to 41). Twenty patients (59 %) were women and 19 patients (59 %) were diabetics. Owing to sternal wound infection complications, 16 patients (47 %) were readmitted to the department. VAC was used following the previous failure of the conventional treatment strategy in 7 patients (21 %). RESULTS: Thirty-three patients (97 %) were treated successfully. One patient (3 %) died of multiple organ failure. The overall length of hospitalization was 34.6 days (range 9 to 62). The median number of dressing changes was 4.6 (range 3 to 10). The median VAC treatment time until surgical closure was 9.2 days (range 6 to 21 days). VAC therapy was solely used as a bridge to definite wound closure. Three patients (9 %) with chronic fistula were re-admitted 1 to 6 months after VAC therapy. CONCLUSIONS: VAC therapy is a safe and reliable option in the treatment of sternal wound infection in cardiac surgery. VAC therapy should be considered an effective adjunct to conventional treatment modalities for the treatment of extensive and life-threatening wound infections following cardiac surgery, particularly in the presence of risk factors.