PMC2911615_01
Oblique view of the needle at the posterior cord.
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fig1
Arrow Tuohy needle (Arrow International; Reading, PA) connected to a nerve stimulator (standard for our institution set at pulse duration 0.3 ms, current 1.5 mA, frequency 2 Hz) was advanced in a saggittel plane toward the nerves with 3D US visualization (Figure 1). After correct positioning was corroborated by appropriate distal motor nerve response of the posterior cord, a 19-gauge stimulating catheter (Stimcath, Arrow International; Reading, PA) was advanced 5 cm past the needle tip under continuous stimulation.
Oblique view of the nerve catheter inferior to the posterior cord.
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fig2
After injection of 30 cc of local anesthetic (ropivacaine 0.5%), the catheter was visualized lying across the nerve bundle (Figure 2).