Subcutaneous tunnelling of epidural catheters for postoperative analgesia to prevent accidental dislodgement: a randomized controlled trial.

The use of subcutaneous tunnelling to prevent movement of epidural catheters was examined in a prospective controlled trial. There were 113 patients in the standard group and 100 in the tunnelled group. The groups were similar with respect to age, sex and weight. There were 176 thoracic catheters, and 37 lumbar catheters. Mean duration of catheterization in the tunnelled group was 3.5 +/- 1.3 days and in the standard group, 3.1 +/- 1.5 days. In total, 60 catheters moved significantly from their initial position: 17 (28%) moved inwards and 43 (72%) moved outwards. 159 catheters were still functioning at the time of their removal, 76 standard and 83 tunnelled. This represents 67 and 83% of the two groups respectively. Subcutaneous tunnelling was shown to prevent clinically significant inwards (P = 0.043) and outwards (P = 0.0005) movement of epidural catheters and is more likely to result in a functional epidural blockade at the time of catheter removal (P = 0.0084).