Sternal Reconstruction & Stabilization

Deep sternal wound infection (DSWI) — also called post-sternotomy mediastinitis — is one of the most feared complications of cardiac surgery. It occurs in approximately 1–3% of patients after open heart surgery and carries a reported mortality rate of 10–47% without aggressive treatment.^1,2 Flap-based reconstruction, combined with sternal stabilization and antibiotic therapy, is the cornerstone of modern management and has dramatically improved survival compared to earlier approaches.

Understanding the Problem: Sternal Wounds After Cardiac Surgery

The sternum is divided down the midline (median sternotomy) to access the heart during most cardiac operations — including coronary artery bypass grafting (CABG), valve replacement, aortic surgery, and heart transplantation. At the end of the operation, the sternum is wired closed and the overlying tissue is sutured shut. In most patients, this heals uneventfully. But in a significant minority, wound complications develop:

• Superficial wound dehiscence: Separation of the skin and subcutaneous layers without involvement of the sternum itself; typically managed with local wound care or secondary closure
• Sternal dehiscence: Separation of the sternal wires, allowing the two halves of the sternum to move independently; this causes pain, instability, and clicking with breathing — and creates the conditions for deep infection
• Deep sternal wound infection (DSWI) / Mediastinitis: Infection extending into the mediastinum (the space behind the sternum containing the heart and great vessels). This is the most dangerous form — DSWI is associated with high mortality and requires urgent surgical debridement and flap reconstruction^1,2

Who Is at Risk?

Certain patient factors significantly increase the risk of DSWI after cardiac surgery:³

• Diabetes mellitus — particularly poorly controlled diabetes or insulin dependence
• Obesity
• Use of both internal mammary arteries (bilateral IMA harvest) for coronary bypass, which devascularizes the sternum
• Chronic obstructive pulmonary disease (COPD)
• Reoperation or prolonged bypass time
• Immunosuppression (transplant patients, corticosteroid use)
• Renal failure
• Smoking

VAC Therapy: Bridging to Reconstruction

In the initial management of DSWI, the wound is opened, debrided of infected and necrotic tissue, and all non-viable material — including infected sternal bone — is removed. Negative-pressure wound therapy (VAC/NPWT) is then applied to the mediastinal cavity. VAC therapy reduces bacterial load, promotes granulation tissue, and manages the high volume of wound exudate while the patient is optimized for definitive reconstruction.⁴ Preoperative VAC use before pectoralis flap reconstruction has been associated with reduced flap complications in some series. VAC is a bridge — not a definitive treatment — in DSWI; patients should proceed to flap closure as soon as they are medically stable.

Flap Reconstruction: The Mainstay of Treatment

Vascularized flap reconstruction is the definitive treatment for DSWI. Flaps bring in a new blood supply to a devitalized field, fill the dead space of the mediastinal cavity, and provide durable soft tissue coverage over the reconstructed sternum.^1,2

Pectoralis Major Advancement Flaps

The pectoralis major muscle is the workhorse flap for sternal wound reconstruction, used in the vast majority of cases. The muscle can be used in two configurations:

• Advancement (turnover) flap: The pectoralis is detached from the humerus and advanced medially to fill the sternal wound. The dominant blood supply — the thoracoacromial artery — remains intact, ensuring reliable perfusion
• Turnover flap: The muscle is detached from its lateral insertion and "turned over" into the mediastinum like the page of a book, based on the perforating branches of the internal mammary artery (when available)

Bilateral pectoralis major flaps are used when the sternal defect is wide or when unilateral coverage is insufficient. Multiple studies confirm that pectoralis major flaps achieve reliable wound closure with low rates of flap failure.^5,6 A cadaveric study confirmed the anatomical reliability of this approach for providing full sternal coverage.³

Rectus Abdominis Flap

The vertical rectus abdominis musculocutaneous (VRAM) flap is the preferred alternative when both pectoralis muscles are not available — as occurs when both internal mammary arteries were harvested for bypass grafting (eliminating the perforating branches that would supply a turnover pectoralis flap) or when the pectoralis muscles are atrophic, damaged, or previously used. Based on the superior epigastric artery, the VRAM flap provides reliable muscle bulk for filling the inferior mediastinum and lower sternal wound. It is particularly valuable for DSWI extending into the sub-xiphoid region.⁷

Omental Flap

The omentum — the intra-abdominal fatty apron — has exceptional antibacterial and angiogenic properties. It can be brought into the chest through a laparotomy incision to fill the mediastinal dead space, particularly in cases with deep infection extending behind the heart or when pectoralis coverage alone is insufficient. Omental flaps are often combined with pectoralis flaps in the most severe DSWI cases with infection extending into the deep mediastinum.^2,8 A systematic review and meta-analysis by Cancelli et al. demonstrated that pectoralis major and omental flaps provide comparable mortality benefits when used appropriately, with the omental flap favored for deeper infections.¹

Hardware Management: Remove or Retain?

A key decision in DSWI management is what to do with the sternal wires and any other hardware (pacemaker leads, surgical clips). In most cases, infected wires must be removed as part of debridement — leaving infected hardware in place perpetuates the infection and prevents healing. However, sternal stability must then be addressed:

• Re-wiring: In cases with minimal contamination and viable sternal bone, the sternum can be re-approximated with new wires or plates after debridement
• Sternal plating (rigid fixation): Titanium sternal plating systems can provide superior stability compared to wires alone, particularly in patients with sternal necrosis or poor bone quality. Rigid fixation prevents paradoxical sternal motion, improves respiratory mechanics, and may reduce postoperative pain. Some evidence suggests plating reduces hospital stay and mechanical ventilation duration
• No sternal re-approximation: When sternal bone is extensively infected or necrotic and must be widely excised (sternectomy), no re-approximation is possible. Flap bulk fills the resultant cavity and provides stability

Collaboration with Cardiac Surgery

DSWI management is a collaborative undertaking between plastic surgery and cardiac surgery. Dr. Lakhiani works directly with cardiac surgeons to plan the timing of debridement, hardware decisions, and flap reconstruction — often performing the reconstructive portion of the procedure at the same sitting as the cardiac surgery debridement. Infectious disease consultation is essential to guide antibiotic selection, duration, and suppressive therapy in complex cases.