“…Unilateral application can be conducted on one or more vertebral levels, with or without catheter insertion ( 5 , 8 , 10 , 12 , 24 ). Bilateral application is most commonly a single shot technique on two levels, depending on the type of surgery, in order to avoid potential complications (local anaesthetic toxicity and haemodynamic instability) ( 5 , 8 , 10 , 12 , 25 ). Unilateral application is used in breast surgery, thoracic surgery, cardiac pacemaker insertion, rib fractures, open cholecystectomy, liver resections, oesophageal and gastric surgery, partial or complete nephrectomies, inguinal herniorraphy ( 5 , 7 , 8 , 10 , 12 , 13 , 15 - 18 , 23 ).…”