Interscalenic brachial plexus block for arthroscopy in shoulder surgery using levobupivacaine 0.5% versus ropivacaine 0.75% plus tramadol and clonidine: quality, onset and duration

摘要

Background: The purpose of this study was to investigate the efficacy of levobupivacaine versus ropivacaine, both with tramadol and clonidine for interscalenic brachial plexus block in shoulder arthroscopy.Methods: A total of 328 patients undergoing shoulder arthroscopy were randomized to receive an anesthetic mix composed of 30 ml of either 0.5% levobupivacaine (150 mg) or 0.75% ropivacaine (225 mg), both containing 100 mg tramadol and 75 μg clonidine. In all cases, the block was performed using a modified Winnie's approach. Twenty-four ml were injected into the interscalene fossa, while 6 ml was used to block the suprascapular nerve. The sensory and motor onset times, and the time required to achieve surgical anesthesia were assessed immediately after the block. Motor block, analgesia and the number of boluses administered by patient-controlled analgesia (PCA) were also evaluated at 2, 6, 12, 18, and 24 h following surgical intervention.Results: The mean sensory and motor onset times as well as the time required to achieve surgical anesthesia in the group treated with levobupivacaine were significantly lower (p < 0.001) than in the group treated with ropivacaine. The quality of the block 24 h after surgery was significantly better in the former group (VAS ≅ 0; p < 0.05; motor scale = 0.65; p < 0.001). Bolus administration by PCA was considerably lower in patients treated with levobupivacaine.