Patient-controlled interscalene analgesia with ropivacaine 0.2% versus bupivacaine 0.15% after major open shoulder surgery: The effects on hand motorfunction

We compared the effects of patient-controlled interscalene analgesia with r opivacaine 0.2% and patient-controlled interscalene analgesia (PCIA) with b upivacaine 0.15% on hand grip strength after major open shoulder surgery. S ixty patients scheduled for elective major shoulder surgery were prospectiv ely randomized to receive in a double-blinded fashion either ropivacaine or bupivacaine through an interscalene catheter. Before surgery, all patients received an interscalene block (ISB) with either 40 mt of 0.6% ropivacaine or 40 mt of 0.5% bupivacaine. Six h after ISB, the patients received a con tinuous infusion of either 0.2% ropivacaine or 0.15% bupivacaine for 48 h. In both groups, the PCIA infusion rate was 5 mL/h plus a bolus of 4 mt with a lockout time of 20 min. Strength in the hand was assessed preoperatively , 24 h, and 48 h after ISB and 6 h after stopping the infusion of local ane sthetic. The presence of paresthesia in the fingers was checked. Pain relie f was assessed using a visual analog scale; side effects were noted, and th e patients rated their satisfaction 54 h after the block. A significant dec rease of strength in the hand was observed in the Bupivacaine group 24, 48, and 54h after ISB (P < 0.05). Paresthesia was more frequently reported in the Bupivacaine group for the second and third fingers 48 h after ISB (P < 0.05) and in the first three fingers 6 h after discontinuation of the local anesthetic infusion (P < 0.05). The pain score was similar in the two grou ps at all times, and patient satisfaction was comparable between the two gr oups. We conclude that the use of the PCIA technique with ropivacaine 0.2% or bupivacaine 0.15% provides a similar pain relief after major shoulder su rgery. However, ropivacaine 0.2% is associated with better preservation of strength in the hand and less paresthesia in the fingers.