The stimulating needle group was significantly noninferior to the stimulating catheter group ( difference [ 95 % CI ] in mean verbal response scale pain score [ stimulating needle vs. stimulating catheter ] of -0.16 [ -0.61 to 0.29 ] , P < 0.001 ; percentage difference in mean IV morphine equivalent dose of -5 % [ -25 to 21 % ] , P = 0.002 ) and to ultrasound-only group ( difference in mean verbal response scale pain score of -0.28 [ -0.72 to 0.16 ] , P < 0.001 ; percentage difference in mean IV morphine equivalent dose of -2 % [ -22 to 25 % ] , P = 0.006 ) .