The lungs

The two lungs are basically very similar (Figure 9.2). The right lung is made up of three lobes and the left of two lobes. The lingular segment of the left lung corresponds to the middle lobe on the right. Each lobe is divided into segments.

The thoracic cage is lined by the pleura. There are two layers, the parietal and visceral, which are continuous with each other and enclose the pleural space. The parietal pleura is the outer layer and lines the thoracic cavity. The visceral pleura covers the surface of the lung, entering into the fissures and covering the interlobar surfaces. The two layers are lubricated by a thin layer of pleural fluid lying within the pleural space, which, in healthy individuals, contains no other structure.

The oesophagus

The oesophagus is a muscular tube stretching from the pharynx to the stomach. It is composed of mucosa and circular and longitudinal muscle layers. The oesophagus enters the stomach below the diaphragm at approximately the level of the eleventh thoracic vertebra.

The most common reason for pulmonary and oesophageal resection is a malignant tumour (carcinoma). A small percentage of tumours can be benign.

Lung cancers are classified into two main categories (NICE 2005):

Non-small-cell tumours are treated by resection if possible, if the tumour can be safely removed with clear margins and if metastatic disease is not in evidence. Small-cell cancer is virtually always widespread at diagnosis, so surgery is usually not an option.

Malignant tumours of the oesophagus are generally adenocarcinoma, especially in the lower end. They may have arisen in the cardia of the stomach and spread proximally. In the middle and upper oesophagus, squamous carcinomas predominate.

Benign tumours of the oesophagus and lungs are rare.

Pre-operative investigations

Patients are assessed pre-operatively in order to establish the nature of the lesion and whether they are fit for surgery. The following investigations are commonly done.

This incision is most commonly used for operations on the lung (Figure 9.3). It is a curved incision that starts at the level of the third thoracic vertebra and follows the vertebral border of the scapula and the line of the rib extending forward to the anterior angle or costal margin. An incision through the bed of the fifth or sixth rib is used for pneumonectomy or lobectomy.

The muscles involved are the trapezius, latissimus dorsi, rhomboids, serratus anterior and the corresponding intercostal. A small piece of rib, approximately 1 cm, may be removed to allow easier retraction and avoid a painful fracture.

Anterolateral thoracotomy

This incision is used primarily for cardiac surgery but can be used to perform pleurectomy.

The incision starts at the level of the fifth costal cartilage. At the sternal edge it follows the rib line below the breast to the posterior axillary line. The muscles cut are pectoralis major and minor, serratus anterior and the corresponding intercostal (Figure 9.4).

Pneumonectomy

Extrapericardial pneumonectomy is carried out for tumours involving a main bronchus. The whole lung is removed and the resulting cavity will fill with protein-rich fluid and fibrin over a period of weeks.

Lateral shift of the mediastinum, upward shift of the diaphragm and reduction of the intercostal spacing on the operated side reduce the size of the cavity.

Intrapericardial pneumonectomy is a more radical procedure involving the removal of part of the pericardium. This is required when the tumour growth involves the pericardium.

Lobectomy

This means removal of a complete lobe with its lobar bronchus. On the right side, two lobes can be removed together – the upper and middle or middle and lower. Removal of the upper lobe on the right, known as a ‘sleeve resection’ can sometimes include a section of right main bronchus.

Segmental resection

A segment of a lobe along with its segmental artery and bronchus are removed.

Wedge resection

This is a small local resection of lung tissue.

Lung volume-reduction surgery

Lung volume-reduction surgery is a procedure designed to improve respiratory function in patients with severe bullous emphysema. These patients present with hyperinflated lungs and a flattened diaphragm. By excising the bullous tissue and shaping the remaining lung, expansion of the healthy lung and doming of the diaphragm can be achieved. This will result in improved respiratory mechanics and symptomatic relief of dyspnoea (breathlessness). Patients should undergo a period of pulmonary rehabilitation pre-operatively to maximise their respiratory function.

Complications of pulmonary surgery

The major complications of pulmonary surgery are listed in Table 9.1.