SummaryWe report the occurrence of an accidental pleural puncture by an epidural catheter that happened during the attempted induction of thoracic epidural anaesthesia using a paramedian approach in an awake patient. The incorrect placement of the catheter was recognised while the patient was undergoing thoracoscopic surgery. The possibility of accidental pleural puncture during attempted thoracic epidural catheter placement by either the paramedian or the midline approach should be borne in mind. A misplaced catheter may injure lung tissue and result in a potentially dangerous intra-operative tension pneumothorax.Keywords Anaesthetic techniques, regional; epidural, thoracic. Complications. ...................................................................................... Correspondence to: Dr A. Zollinger Accepted: 23 March 1997 Thoracic epidural anaesthesia is frequently used in combination with general anaesthesia to achieve excellent peri-operative analgesia in patients undergoing upper abdominal and thoracic surgery [1, 2]. The technique may be associated with beneficial respiratory and haemodynamic effects [3][4][5]. However, this procedure is not free from complications, which include dural puncture with high spinal block [6, 7], blood vessel puncture with subsequent formation of an epidural haematoma [8,9], prolonged arterial hypotension, transection and knotting of the catheter [10], infection [11,12] and neurological sequelae [13]. Only a few cases of accidental puncture of the pleural cavity after thoracic epidural anaesthesia have been reported [14][15][16]. We report a case with direct intraoperative visualisation of the thoracic epidural catheter perforating the parietal pleura in a patient undergoing video-assisted thoracoscopic surgery. Case historyA 73-year-old female patient (height: 149 cm, weight: 60 kg) with chronic pneumonia of the right lower lobe was referred for diagnostic thoracoscopic lung biopsy. Her chest X-ray showed an encapsulated pleural effusion in the midzone of the right lung. Pre-operative laboratory data, lung-function tests and electrocardiogram were all normal. The patient had no history of spinal pathology.Routine monitoring was attached to the patient, who was positioned in the right lateral position with her knees bent and her spine flexed. The space between the spinous processes of the sixth and seventh thoracic vertebrae (T 6/7 interspace) was infiltrated with local anaesthetic. A 16G Tuohy needle (Portex Ltd, Hythe, Kent, UK) was inserted into the T 6/7 interspace using a right-sided paramedian approach (2 cm to the right of the midline). The loss-ofresistance technique was used with the aid of a 10-ml saline-filled glass syringe. The needle was advanced perpendicular to the skin until it hit the vertebral lamina on the right side. The tip of the needle was then redirected in the mediocranial direction and the typical loss of resistance was felt 7 cm deep to the skin. The epidural catheter was threaded 3 cm beyond the tip of the needle without any problems...