Thoracic Surgery

Imaging

Chest x-ray, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US) and synchronised CT-positron emission tomography (CT-PET) are the most commonly used modalities. Chest x-ray is useful as a baseline and also for early postprocedure follow-up. Contrast enhanced CT of the chest and upper abdomen provides the best anatomical information and is used for both preoperative planning and follow up. Low radiation-dose protocols are being used successfully in some lung cancer screening projects and there is some evidence suggesting that screening certain groups may lead to longer survival and this may become common practice. CT-PET can be used to identify potential spread to local lymph nodes, as well as distant metastases outside the chest. MRI is most useful to study soft tissues, and in malignancy, in particular, to determine the extent of chest wall and diaphragm invasion, spinal invasion and for distant spread to the liver or brain. US is useful to guide drainage of collections, siting of chest-drains and for guiding biopsy of superficial or pleural-based lesions. In some cases, before placing a nonemergency chest drain, US or CT scanning is performed to minimise the risk of complications.

Lung Function Tests

Lung function tests give a detailed portrait of the physiological effects of individual chest diseases, and can track changes over time or as a result of treatment. When surgery is contemplated, lung function tests help assess the patient’s capacity. Tests include:

• Measurement of air flow into and out of the alveoli, that is, forced expiratory volume in 1 second, forced vital capacity, peak air flow, total lung capacity, alveolar ventilation.

• Measurement of gas diffusion across the alveolar–capillary interface, usually involving measuring rates of carbon monoxide diffusion.

• Assessing the amount of dead space by calculating the residual volume and total lung capacity.

• Assessing exercise capacity, for example, by the 6-minute walk test or by formal cardiopulmonary exercise testing.

• Baseline arterial or capillary blood gases.

Bronchoscopy

Flexible bronchoscopy can be performed with topical local anaesthesia and minimal or no sedation. It is possible to examine down to segmental bronchi, obtain small biopsies and clear secretions.

For cancer staging, transbronchial US (endobronchial US, EBUS) allows biopsy of lymph nodes close to the airway to the level of the lobar bronchi. This can be combined with transoesophageal US (EUS) to allow more lymph node stations and the left adrenal gland to be biopsied.

Rigid bronchoscopy is performed under general anaesthesia and allows passage of larger instruments, including a flexible bronchoscope, for removal of foreign bodies, obtaining large biopsies, opening of the airway and control of bleeding.

Pleural Aspiration and Percutaneous Biopsy

Aspiration of pleural effusions for cytological examination can be performed using a standard wide-bore needle and syringe. Blind pleural biopsy is now discouraged because of its relatively low yield and high complication rate. Many thoracic masses are amenable to percutaneous biopsy under US or CT guidance, although thoracoscopy or direct surgical cut-down to the lesion (or a procedure that combines both) has the best yield.

Video-Mediastinoscopy

A mediastinoscope is used to biopsy paratracheal and subcarinal lymph nodes. The instrument is a rigid tube incorporating fibreoptic light guides; it is inserted via a skin incision above the suprasternal notch and passed caudally along the plane of the pretracheal fascia ( Fig. 31.1A and B ). The route passes close to the azygos vein, superior vena cava, innominate artery, arch of the aorta, pulmonary artery and the recurrent laryngeal nerves posterolaterally on each side. These structures and the oesophagus are at risk of damage and, although rare, this must be explained to the patient. Mediastinoscopy gives access to the mediastinum except for the subaortic fossa (below the aortic arch and often containing lymph nodes). Access to this area is obtained by anterior mediastinotomy or video-assisted thoracic surgery.

The number of mediastinoscopies has fallen because of the yield from CT-PET scanning and Endoscopic US (EBUS and EUS).

Thoracoscopy

This is more commonly known as video-assisted thoracoscopic surgery or VATS . It is usually performed under general anaesthesia but basic procedures may use local anaesthesia with sedation. In addition, some units perform VATS under deep sedation with spontaneous ventilation, even for major resections. Instruments for viewing and operating are inserted through small incisions in the chest wall.

Thoracoscopy is the preferred technique for pleural biopsy, pneumothorax treatment and evacuation of early empyema and is also used to sample mediastinal lymph nodes and perform cervical (thoracodorsal) sympathectomy. In the United Kingdom, VATS is also becoming increasingly common for a range of more complex procedures, for example, lobectomy. In some units, the rate of VATS lobectomy is more than 60% overall and >90% for stage 1 lung cancer.

VATS procedures may be performed via a multiportal or uniportal approach. In both, there is a nonrib-spreading ‘utility’ incision of about 2 to 8 cm. In the uniportal approach, all instruments and the camera are passed through the single utility port and this incision can also be used for the drain at the end of the procedure. In the multiportal approach, one to three further port incisions are made for a video-telescope and surgical instruments. In this approach, drains can be placed in suitable ports. Any resected specimen is placed in an extraction bag so it can be removed intact via the utility incision. The position of the ports depends on the procedure being performed and surgeon preference. The most performed VATS is via lateral chest wall incisions but a subxiphoid incision is used by some surgeons for selected procedures, for example, thymectomy, lung volume reduction surgery or lobectomy.

Anterior Mediastinotomy

Anterior mediastinotomy (see Fig. 31.1C ), a form of minithoracotomy, may be used to obtain biopsies from anterior mediastinal lesions, for example, thymic tumours. The approach can be left or right of the sternum, either intercostally or with costal cartilage resection. Left anterior mediastinotomy affords good access for biopsy of subaortic fossa masses. VATS is increasingly replacing anterior mediastinotomy as the preferred method of accessing these sites.

Thoracotomy

Thoracotomy, described later, gives full access to the paratracheal, subcarinal and hilar lymph node groups, the great vessels, oesophagus, lung and pericardium and is used when less invasive procedures are inappropriate or have failed.

Tracheostomy

Principles of Tracheostomy

A tracheostomy ( Figs 31.2 and 31.3 ) is an artificial opening into the trachea to provide a secure airway when the pharyngeal airway or larynx needs to be bypassed. With time, an epithelialised fistula develops between the skin and trachea, which allows tracheostomy tubes to be changed and the airways cleaned with ease. In many units ‘percutaneous tracheostomy’ is performed using a ‘Seldinger-type’ technique. However, the technique of ‘open’ tracheostomy should be familiar to most surgeons.

Indications for tracheostomy include:

• Permanent functional obstruction of the upper airway, for example, carcinoma of larynx.

• Temporary or potential upper airway obstruction, for example, facial fractures, major head and neck operations or injuries.

• Long-term ventilatory support, when prolonged endotracheal intubation would otherwise be likely to cause permanent significant tracheal damage. Tracheostomy also provides continuous access to the lower airways for bronchial aspiration and toilet.

Tracheostomy should be a planned procedure performed in the operating room under general anaesthesia. It is not an emergency procedure for patients with upper airway obstruction. For these, endotracheal intubation or cricothyroidotomy ( Fig. 31.4 ) should be used.

Thoracotomy

Most thoracotomies are now devised to spare at least some muscles from being divided.