The chest wall

Tumours of the chest wall

These can be tumours of any component of the chest wall, i.e. bone, cartilage and soft tissue. They are treated similarly to those that occur in other sites and only require specialist input if major resection and chest wall’ reconstruction are contemplated. The most common tumour is that of the rib (chondroma or osteoma) and presentation is as a hard swelling over the rib. Malignant tumours are painful and destructive and require wide resection. Even so, there is a tendency for tumours to recur and histological classification is difficult. Tumours of the sternum are usually malignant. Lung and pleural tumours may involve ribs and destroy them.

Most lesions may be seen on a chest radiograph but occasionally CT or isotope bone scanning is required. Excision biopsy is often the best way to deal with a rib neoplasm because the differentiation between benign and malignant growths may be difficult. This avoids the risk of ‘spillage’ and tumour seeding in the wound of an incision biopsy. If a major resection is to be planned, it may be preferable to know the nature of the lesion before surgery. The principle of surgery .s to remove the rib along with the rib immediately above and below, and a length well past the margins of the tumour. Reconstruction is possible using a prosthetic material Marlex or acrylic plates) to provide some stability to the :hest wall. Myocutaneous flaps are occasionally employed to over extensive tissue defects and therefore prior discussion with a plastic and reconstructive surgeon may be useful.

For lesions that are not amenable to resection, chemotherapy or radiotherapy, although unlikely to be curative, may provide symptomatic relief.

Other diseases of the chest wall

Congenital abnormalities are often incidental findings on chest radiography (bifid rib) but there are some important exceptions.

Cervical rib

This rib is usually represented by a fibrous band originating from the seventh cervical vertebra and inserting on to the first thoracic rib. It may be asymptomatic but because the axillary artery and brachial plexus course over it a variety of symptoms may occur. The lower trunk of the plexus (mainly T1) is compressed, leading to wasting of the interossei and altered sensation in the T1 distribution. Compression of the axillary artery may result in a post stenotic dilatation with thrombus and embolus formation. Treatment is by division or removal of the rib by a supraclavicular or an axillary approach.

Pectus excavatum

The sternum is depressed, with a dish-shaped deformity of the anterior portions of the ribs on one or both sides. It is probably never a cause of respiratory problems but may coexist with asthma, which is a common condition of children and young people. It may come to light during the growth spurt at adolescence when, of course, the teenager is particularly sensitive about appearance. Most patients are asymptomatic and the only justification for treatment is on cosmetic grounds. Some surgeons, and their referring doctors, make a very good case for this but the risk of morbidity and of a less than perfect result must be clearly spelt out to the patients and their parents.

The operation involves mobilising the sternum with the costal cartilages and holding this central panel anteriorly with a steel bar. Surgery is best left until the late ‘teens when further growth of the chest wall is unlikely. It is worth recommending some body-building exercises because muscle development not only masks the skeletal deformity but boosts confidence.

Pectus carinatum (pigeon chest)

In this condition the sternum is elevated above the level of the ribs and treatment is offered for cosmetic reasons. The sternum is mobilised and allowed to fall back into place.

Pulmonary sepsis

Infections of the chest wall

These are unusual but may occur following osteomyelitis of the underlying rib. An empyema of the underlying thoracic cavity may discharge through the chest wall (empyema necessitans) leaving a chronic sinus. Sterile pus should alert the clinician that tuberculosis is present. Treatment of the chest wall infection depends on adequate treatment of the underlying condition.

Empyema

This is the end point of a number of conditions that result in the presence of pus in the pleural space, pleural thickening surrounding the walled-off infection and finally restricted lung movement on the affected side as a result of fibrosis. The presence of white cells and organisms is not sufficient to make the diagnosis of empyema.

The classic aetiology and still probably the most common is postpneumonic. A ‘syn-pneumonic effusion’ becomes colonised by bacteria and, at this stage, there is turbid but thin fluid, minimal pleural thickening and a mobile underlying lung. This is nor properly called an empyema, an important point because the old-fashioned methods of rib resection would be fatal if applied to this condition and simpler treatments are effective. Untreated, this infected effusion develops into an empyema with thick pus in the pleural space surrounded by inflamed pleura thickened by deposition of fibrin. Finally, the cortex organises to form dense scar tissue or a ‘fibrothorax’. Any cause of fluid collec­tion, once contaminated, can evolve to reach this same end point (Table 47.6). Once established, any contaminated collection in the chest can result in empyema.

Symptoms. There are symptoms of pus at any site, namely swinging pyrexia with general malaise. Finger clubbing and weight loss are signs of chronicity. Progressive dyspnoea occurs as the hemithorax becomes more rigid. There may also be signs and symptoms of various predisposing conditions (see above). Pus may discharge into the overlying skin (empyema necessitans). Since the introduction of antibiotics, chronic empyema is not often seen but it is still a serious problem when it occurs.

Treatment. The management depends on the stage of the empyema.

 

Early empyema (thin pus, mobile lung and thin pleura). At this stage a brief period of pleural drainage, with underwater seal and adequate dosage of appropriate antibiotics, should result in resolution but inadequate treatment or no treatment will lead to a chronic empyema — a much more serious problem. Complete drainage and re-expansion of the lung should be achieved before the drains are removed. This need not take more than 2—3 days. Pus should be sent for microscopy and culture before antibiotic therapy.

Established empyema (adherent lung caused by inflamed and thickened pleura with thick pus in the empyema space). At this stage the old treatment of rib resection with open drainage is safe in that the lung is tethered. However, it is inelegant, protracted and incomplete in its results. It is better to insert drains, through a small thoracotomy (with resection of rib) if practical. This is best done under a general anaesthetic, except in desperate circumstances, and all the loculi are broken down, ensuring free drainage and the siring of one or two carefully situated tubes. The drains should span the cavity, have the last side hole just within the ribs, and be tracked to lie anterior to the midaxillary line so that they are comfortable and do not kink as the patient lies back.

Video-assisted thoracoscopic placement of drains is an increasingly appropriate alternative approach. Suction drainage is employed on chest closure and this is continued until the patient is ready for mobilisation. Provided there is no air leak (and there is usually none) portable vacuum drains, which the patient is able to manage at home, are inserted. Appropriate antibiotics are also given. A daily record of the amount drained is kept by the patient and, once the drainage is less than 25—5 0 ml/24 hours of serous fluid (it never becomes zero), the drain is removed.

Chronic empyema. If progression to a chronic fibrothorax has occurred, aspiration or drainage of pus will not lead to expansion of the lung because there is considerable fibrosis constricting the lung parenchyma.

Thoracotomy and decortication. A formal thoracotomy is performed and the thickened parietal pleura and the fibrin peel overlying the lung are painstakingly removed, piecemeal if necessary. This allows the lung to expand but theme is often considerable blood loss from the raw surfaces. Wide bore drains are inserted and connected to an underwater drainage system. Protracted air leak is common. When the leak has stopped (often up to 10 days later), the drains are removed. Antibiotics are given to cover organisms grown from the pus.

Postpneumonectomy empyema

This is discussed in the section concerning lung resections.

Lung abscess

Abscesses in the lung do not occur unless the underlying infection has caused thrombosis of the segmental artery and vein leading to infection with tissue necrosis. The most common causes are secondary to a chronic upper respiratory tract infection (sinusitis, dental abscess) or following bronchial obstruction from a neoplasm (Table 47.7).

Diagnosis and treatment. The chest radiograph usually demonstrates a cavitating shadow which is similar in appear­ance to a necrotic bronchial carcinoma or less commonly a fungal infection. The diagnosis is confirmed with a combina­tion of sputum culture, bronchoscopy and radiography. Most acute abscesses resolve with appropriate antibiotic therapy and postural drainage. The course of antibiotics is usually the highest permitted dose for a prolonged period. The virulent organism may change with such a prolonged antibiotic assault and the sputum must therefore be regularly monitored. Surgery is not usually part of the treatment. It is better for a lung abscess to drain via the bronchus and the contents are coughed up. Inserting a percutaneous drain creates a particularly difficult form of bronchopleural fistula.