Evaluation of an insulated Tuohy needle system for the placement of interscalene brachial plexus catheters

Major shoulder surgery can be extremely painful. Interscalene brachial plexus catheters provide excellent postoperative analgesia but are technically difficult to place. A new insulated Tuohy needle system for plexus catheterisation is now available. This prospective study examined its ease of use and the postoperative analgesia produced by patient-controlled interscalene analgesia with ropivacaine 0.2%. Nineteen patients undergoing major shoulder surgery were studied. Interscalene brachial plexus blocks were performed using a modified Winnie technique with the insulated Tuohy needle and a nerve stimulator. After injection of ropivacaine 0.75% 30-40 ml into the plexus, a catheter was inserted. Block and catheter insertion times were recorded. All 19 patients had successful blocks and had catheters successfully threaded. Catheter infusions provided successful analgesia (visual analogue pain score <5/10) in 18 patients, with one failure, giving a 95% success rate. Mean [range] catheter insertion time was 3.6 [1-10] min. Decreased block and catheter insertion times were associated with experience with the equipment when comparing the mean (SD) times for the first seven catheters and the last seven catheters inserted (12.1 (4.2) min vs. 7.9 (2.4) min), p<0.05). It is concluded that the insulated Tuohy needle system for interscalene catheterisation proved easy to use in the hands of someone who had not used it before, and can be recommended.