Fig. 1From: Reduction of leakage from insertion site during continuous femoral nerve block with catheter-through-needle versus catheter-over-needle technique for postoperative analgesia after total knee arthroplasty: a randomized controlled trialCatheter insertion site 48 h after the start of continuous femoral nerve block. A: No leakage. White filter paper was not dyed at all. B: The filter paper was completely dyed blue and the soaked paper was torn. The leakage could be identified easily by adding indigo carmine to local anestheticsBack to article page