Brief introduction

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  Common etiologies for chest wall defects include tumor resection, deep sternal wound infections, chronic empyemas, osteoradionecrosis (ORN), and trauma.

  
  
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  Mediastinitis occurs in 0.25–5% of patients undergoing median sternotomy.

  
  
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  Historically, mortality approached 50% in these patients.

  
  
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  Sternal wound infections may be classified into three distinct types as described by Pairolero and Arnold ( Table 14.1 ).

  
  
  
  
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    Type 1: wounds that occur in the first several postoperative days and are usually sterile.

    
    
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    Type 2: infections which occur in the first several weeks postoperatively.

    
    
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    Consistent with acute deep sternal wound infection, including sternal dehiscence, positive wound cultures, and cellulitis.

    
    
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    Type 3: infections that present months to years later.

    
    
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    Represent chronic wound infection and uncommonly represent true mediastinitis.

    
    
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    Usually confined to the sternum and overlying skin and may be related to osteonecrosis or persistent foreign body.

  
  
  
  

  Table 14.1

  
  

  Classification of infected sternotomy wounds

  
  

  
  
  
  
  
  
  
  
  
  
  
  

  Type I	Type II	Type III
  Occurs within first few days Serosanguineous drainage Cellulitis absent Mediastinum soft and pliable Osteomyelitis and costochondritis absent Cultures usually negative	Occurs within first few weeks Purulent drainage Cellulitis present Mediastinal suppuration Osteomyelitis frequent, costochondritis rare Cultures positive	Occurs months to years later Chronic draining sinus tract Cellulitis localized Mediastinitis rare Osteomyelitis, costochondritis, or retained foreign body always present Cultures positive

   
  
  
  
  
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  Although each mechanism carries individual nuances, they will all require adequate debridement and, when possible, replacement of like with like.

  
  
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  Fundamentally, the chest wall must be restored for the protection of underlying viscera, maintenance of respiratory mechanics, and base for the upper limb and shoulder.

  
  
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  Chest wall reconstruction can be generalized to include skeletal support and soft tissue cover.

  
  
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  Skeletal support to prevent paradoxic chest wall motion is usually required when the defect exceeds 5 cm in diameter.

  
  
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  Generally, this corresponds to those defects exceeding a two-rib resection ( Table 14.2 ).

  
  
  
  

  Table 14.2

  
  

  Regions of the chest wall

  
  

  
  
  
  
  
  
  
  
  
  
  
  
  

  Anterior	Between anterior axillary lines
  Lateral	Between anterior and posterior axillary lines
  Posterior	Between posterior axillary lines and the spine

   
  
  
  
  
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  Posterior chest wall defects may tolerate up to twice the size of those in the anterior and lateral chest due to scapular coverage and support.

  
  
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  Anecdotally, patients who have undergone radiation and have decreased chest wall compliance will tolerate larger resections without skeletal replacement due to an overall fibrosis of their viscera.

  
  
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  Options for skeletal support include various mesh products including PTFE (Gore-Tex), polypropylene, Mersilene (polyethylene–terephthalate)/methylmethacrylate, and acellular dermal matrix ( Fig. 14.1 ) . Furthermore, use of TFL as both graft and flap reconstruction has been described.

  
  

  
  

  
  

  

  
  

  
  

  

  
  

  
  

  

  
  

  
  

  Implantable mesh products including polypropylene (A) , PTFE (Gore-Tex) (B) and acellular dermal matrix (C) .

  
  
  
  
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  Chest wall reconstruction almost always requires some form of soft tissue coverage, as very few defects will close primarily. Reconstructive goals include wound closure with maintenance of intrathoracic integrity, restoration of aesthetic contours, as well as minimization of donor site deformity.

  
  
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  Recruitment of local muscles with or without overlying skin is often the first line of reconstructive offense, including pectoralis major, latissimus dorsi, serratus anterior, and rectus abdominus. The omentum may also be used.

  
  
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  Commonly, the ipsilateral latissimus muscle is divided during thoracotomy incisions, and the authors encourage early communication between surgeons if there are multiple teams in order to mitigate against routine division. Muscle sparing thoracotomies help to preserve both the latissimus and serratus muscles while providing adequate intrathoracic access ( Fig. 14.2 ) .

  
  

  
  

  
  

  

  
  

  
  

  Muscle sparing tooracotomy: The lateral border of the latissimus muscle is identified (B) and retracted (C) so that the latissimus can be spared.

  
  

  (From Ferguson MK. Thoracic Surgery Atlas . Edinburgh: Elsevier©; 2007.)

  
  

Preoperative considerations

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  The importance of a multidisciplinary approach to chest wall reconstruction cannot be underestimated. These patients, whether suffering from malignancy, infection, or trauma, are often also plagued with cardiac or respiratory insufficiency, diabetes, obesity, malnutrition, and generalized deconditioning.

  
  
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  Acquired chest wall deformities are commonly the result of iatrogenic injury. Usually encountered in conjunction with cardiac or thoracic surgery, wound infections, mediastinitis, ORN, refractory empyema, and bronchopleural fistulas can all necessitate chest wall reconstruction.

  
  
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  Utilizing the workhorse flaps described below, combined with general principles of thorough debridement and skeletal stabilization, the surgeon is generally well prepared to reconstruct any deficit. Common chest wall reconstructive problems are described below.

  
  
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  Preoperative risk factors for the development of mediastinitis include older patients, chronic obstructive pulmonary disease, smoking, end-stage renal disease, diabetes mellitus, chronic steroid or immunosuppressive use, morbid obesity including large, heavy breasts, prolonged ventilator support (>24 h), concurrent infection, and reoperative surgery. Other variables include off midline sternotomies, osteoporosis, use of left internal mammary artery (LIMA) or right internal mammary artery (RIMA), long cardiopulmonary bypass runs (>2 h), and transverse sternal fractures.

  
  
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  Empyema is defined as a deep space infection between the layers of visceral and parietal pleura.

  
  
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  The chest cavity, unlike most other regions in the body, is rigid and non-collapsible. Thus, deep space infections, such as empyemas, are unlikely to heal without collapse of dead space or filling of the cavity.

  
  
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  As adjuvant radiation therapy is becoming increasingly common in the treatment of both breast and lung cancer, ORN of the ribs is becoming an increasing problem for reconstructive surgeons.

  
  
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  Management of ORN of the chest wall consists of surgical excision and reconstruction.

  
  
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  Again, should more than two ribs be resected from the anterior chest wall, skeletal support will traditionally be required.

  
  
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  Radiation damage also affects overlying soft tissues, creating hyperpigmentation, decreased pliability, and even ulceration. Thus, recruitment of healthy tissue in the form of local myocutaneous flaps is recommended.

Operative techniques