Back to Topics<<<<

Mediastinum

Mediastinal Emphysema
Accumulation of air in the mediastinum must be defined as mediastinal emphysema. The main cause is the penetrating air through bronchus/oesopahagus into the mediastinal space which in turn may be due to the perforation of oesopahgus due to sharp or blunt trauma or as a result of pathologic changes (ulcer malignancy, abrupt rupture etc.). The main clinical signs of the mediastinal emphysema include:
  • Acute substernal pain
  • Crepitation nearby sternal notch
If the venous return is impaired, oedema may be expressed on head, neck and upper extremities and in most severe cases when the superior vena caval obstruction symptoms occur where distension of the superficial venous network of head, neck and upper extremities is evident. Oedema and swelling of the brain is fatal. Superior vena cava obstruction may result not only due to some mechanical obstruction but also due to malignant processes especially when the malignancy of the upper dome of lungs occurs.

Mediastinitis
The inflammatory process of the mediastinum is referred to as mediastinitis. Main causes are:
  • Surgical intervention
  • Trauma
    • Some other factors which itself are the causes of mediastinal emphysema
The latter factor bears only the historical value because of the modern era of the antibiotics provides the prompt control of mediastinitis. From surgical point of view, we have to pay more attention to septic or purulent mediastinitis for which the main cause is sternostosmy for cardiac surgery. Purulent mediastinitis is complication of cardiac surgery and accounts for 2%. Various types of flora can be found in the cause of suppurative or purulent mediastinitis especially Staphylococcus Epidermidis, Pseudomonas Aeroginosa, E. Coli etc. suppurative mediastinitis occurs within 2 weeks after the operation; but some authors describe that suppurative mediastinitis may occur in 4 to 5 months after the cardiac surgery. Coronary bypass procedure is much complicated with suppurative mediastinitis than surgical intervention. The main suppurative mediastinitis is compromised vascularity during the closer of sternal wounds where we use metallic clasps for tightening (wires), which affect on the blood supply of the sternum.

Signs and Symptoms:
The first sign of the suppurative mediastinitis is the drainage of the exudative and suppurative components. Fever, chest pain, high leucocytosis is also characteristic for suppurative mediastinitis.

Treatment:
This includes:
  • Drainage
  • Debridement (removal) of all necrotic tissues and
  • Plumbing of the dead space with muscular aponeurotic grafting
The thorough opening of the thoracic cavity and removal of necrotic tissue is not carried only from the juxtsternal regions but also from the pericardium and pleural spaces is important. The use of pectoral major muscles for plumbing of dead space is reasonable but care must be taken to keep internal mammary artery (and its branches) intact. Those defects on the lower most portion of mediastinum may be plumbed with rectal muscle graft.

Back to Topics<<<<                            Top of this page^^^^
This article has been written by Dr. M. Javed Abbas.
If you have any comments please do not hesitate to sign my Guest Book.
21:06 21/12/2002