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Central MessagePersistent sternal nonunion in patients presents treatment difficulties because standard fixation methods may fail. Tailoring a surgical plan to each patient's specific needs can enhance outcomes.See Commentary on page XXX. Persistent sternal nonunion in patients presents treatment difficulties because standard fixation methods may fail. Tailoring a surgical plan to each patient's specific needs can enhance outcomes. See Commentary on page XXX. Sternal nonunion is a disabling complication after sternotomy for cardiothoracic exposure. Patients who are obese or have osteoporosis are especially at risk, with standard fixation methods often failing. This case report outlines a management option for persistent sternal nonunion. Institutional review board approval was not required as per institutional policy. The subject provided informed written consent for publication of the study data. A 52-year-old woman with obesity (body mass index, 40), chronic obstructive pulmonary disease, chronic cough, and heart failure (ejection fraction, 40%), presented with sternal instability and chest pain poststernotomy for anomalous right coronary artery reimplantation 5 years prior at an outside facility. The procedure had been complicated by sternal nonunion that was treated with partial sternectomy and pectoralis muscle flaps. A computed tomography scan confirmed persistent sternal nonunion with 1-cm separation between the sternal halves (Figure 1, A). Due to the patient's body habitus, breast reduction to reduce postoperative chest wall weight was performed. This was followed by sternal reconstruction with SternaLock 360 plates (Zimmer Biomet Inc) and circumferential FiberWire (Arthrex Inc). After an aggressive coughing spell on postoperative day 7, severe chest pain, fever, and incisional bleeding occurred. Follow-up computed tomography revealed complete left ribs fracture from the sternum (Figure 1, B). The patient was taken to the operating room, and the left chest wall was seen separated from the sternum at the proximal costal cartilage heads (Figure 1, C). Sternal plating was disrupted and required removal. Chest hematoma was evacuated, and positive gram stain identified therefore washout and vacuum-assisted closure were performed. Cultures were positive for S. epidermidis, requiring a month of intravenous antibiotics and multiple washouts with vacuum-assisted closure changes. The gap between the residual sternum and left ribs widened to 8 cm, with heart and lung parenchyma expanding into the gap (Figure 2, A). Attempts to approximate the left chest wall to the sternum resulted in heart compression and worsened cardiac function. Reconstruction with bridging material was deemed necessary. Five cadaveric fibular bone grafts were utilized to bridge the gap (Figure 2, B and C). All bone graft edges were notched with ¾ cm segments removed, enabling it to inset into the sternum and adjacent rib. Five titanium plates were applied to stabilize the patient's native ribs, grafts, and sternum. One retrosternal Nuss bar, typically used in pectus excavatum repair, was placed for added stabilization (Figure 2, D). Closure of the midline incision was achieved via bilateral pectoralis major advancement flaps. There was subsequent dehiscence of the wound, which required multiple returns to the operating room for revision flaps, including omental flap and advancement abdominal flaps. Cultures obtained grew Klebsiella oxytoca and Corynebacterium tuberculostearicum, and Candida albicans. Exploration noted the lower 2 grafts involved; however, the upper 3 were healed in and without evidence of infection. Multiple debridement and washouts were performed before ultimately removing the 2 lower allografts and plates. At 7 months postoperation, her chest wall remains stable with the remaining grafts and there has been no evidence of recurrent infection. Sterile sternal nonunion is a challenging condition characterized by ≥3 months of sternal nonhealing after sternotomy.1Wu L.C. Renucci J.D. Song D.H. Sternal nonunion: a review of current treatments and a new method of rigid fixation.Ann Plast Surg. 2005; 54: 55-58Crossref PubMed Scopus (46) Google Scholar Signs and symptoms include chest discomfort, sternal instability, drainage, and pain.2Olbrecht V.A. Barreiro C.J. Bonde P.N. et al.Clinical outcomes of noninfectious sternal dehiscence after median sternotomy.Ann Thorac Surg. 2006; 82: 902-907Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar Predisposing factors include old age, smoking, osteoporosis, obesity, severe macromastia, chronic obstructive pulmonary disease, immunosuppression, radiation history, and poor nutritional status.3Robicsek F. Fokin A. Cook J. Bhatia D. Sternal instability after midline sternotomy.Thorac Cardiovasc Surg. 2000; 48: 1-8Crossref Scopus (130) Google Scholar The superior management for sternal dehiscence is debated especially after failed primary repair. Olbrecht and colleagues2Olbrecht V.A. Barreiro C.J. Bonde P.N. et al.Clinical outcomes of noninfectious sternal dehiscence after median sternotomy.Ann Thorac Surg. 2006; 82: 902-907Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar reported that 15% and 13% of patients with sterile sternal nonunion required additional reconstruction and experienced infections, respectively. Management mainly included debridement, rewiring, muscle flaps, and plate fixation. Our initial revision utilized the advanced SternaLock 360 plate fixation, additionally incorporating 3 wide cerclage bands. This system was chosen over SternaLock Blu (Zimmer Biomet Inc), which was successfully utilized by Wu and colleagues1Wu L.C. Renucci J.D. Song D.H. Sternal nonunion: a review of current treatments and a new method of rigid fixation.Ann Plast Surg. 2005; 54: 55-58Crossref PubMed Scopus (46) Google Scholar in 6 cases of sterile sternal nonunion. The SternaLock 360 provides circumferential sternal stability, particularly advantageous in patients with poor bone quality. It can also withstand greater loads, making it preferred in the setting of chronic obstructive pulmonary disease and obesity. Unlike the SternaLock Blu, its screws are not cancellous, which reduces infection risk. The bands were passed through intercostal spaces creating tension for gradual sternal reapproximation. Circumferential FiberWire was added to enhance sternum approximation. Miazza and colleagues4Miazza J. Vasiloi I. Koechlin L. et al.Combined band and plate fixation as a new individual option for patients at risk of sternal complications after cardiac surgery: a single-center experience.Biomedicines. 2023; 11: 1946Crossref Scopus (0) Google Scholar demonstrated favorable outcomes with this technique. The central feature of most repairs involves modifying how stress is applied, focusing on the ribs not just the sternum. This could have caused the complete left rib dehiscence in our patient. Limited literature describes utilizing bone grafts for expansion. However, a successful complex chest reconstruction using carbon fiber printed implants has been reported.5Wang B. Mei X. Liu W. Yu F. Chest wall reconstruction with 3-dimensional custom-made carbon fiber ribs.J Thorac Cardiovasc Surg. 2018; 156: e177-e179Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar Another approach is Omnipore (Matrix Surgical USA); implants manufactured from high-density polyethylene with porous structure that allow tissue ingrowth. With infections, synthetic grafts are discouraged, favoring autografts or allografts. Eradicating infection before graft implantation is also crucial, although certainty is not always achievable. Our patient underwent cadaveric bone grafting after 4 weeks of intravenous antibiotics to attempt infection clearance before reconstruction; however, infection still was an issue with flap coverage breakdown. Sternal nonunion can be challenging in patient populations with multiple predisposing comorbidities. Due to tension of the intrathoracic space, reconstruction with expansion may be required. Developing a surgical plan customized to patients' requirements optimizes outcomes in these complex scenarios.
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