Force of removal for untunnelled, tunnelled and double-tunnelled peripheral nerve catheters.

We compared the force of extraction for peripheral nerve catheters under three different situations in a porcine model using untunnelled, tunnelled and double-tunnelled catheters. Following insertion of the catheter into the porcine model, the catheters were either left untunnelled or a single or double tunnel was created for the catheter. The force required to displace the catheter by one centimetre was then measured in each of the three groups. The mean (SD) force required for displacement of the catheter was 0.23 (0.06) N for the untunnelled catheters, 1.16 (0.51) N for the single-tunnelled catheters, and 4.00 (1.70) N for the double-tunnelled catheters (p < 0.0001). Tunnelling a peripheral nerve catheter leads to a significant increase in the force required for dislodgement. This is increased further by introducing a second tunnel.