[Transthoracic lung punctures].

Transcutaneous needle aspiration (PTT) is a diagnostic technique which consists of biopsying pathological lung tissue using a needle (which in general is specifically designed for the purpose) which is introduced into the thorax transcutaneously. The target is lined up, either radioscopically or using a CT scanner and this enables the needle to be positioned in the centre of the lesion radiologically where one or more biopsies can be taken. According to the type and diameter of the needle these biopsies will enable a histological examination to be performed in addition to a cytological and bacteriological examination. This performance is particularly indicated in the final assessment of a periphery pulmonary nodule which is suspected of being neoplastic where bronchofibroscopy has been non contributory and where an immediate thoracotomy (diagnostic or therapeutic) is not recommended for one or other reason. When performed for this indication the technique often achieves a sensitivity of 90% with an average specificity of 98%. The diagnostic yield for benign tumours is less. It is always necessary to maintain a degree of vigilance in view of the risk of false negative or "benign" results. The complications exist above all of pneumothoraces which occur in 20-30% of cases and which will require a drain in 5-10% of cases. Haemorrhage and haemoptysis are less frequent but potentially fatal even in the absence of any coagulation disturbance.