Multi-injection vs. single injection technique with localization of the medial nerve for infraclavicular block for upper limb surgery

Introduction. The purpose of this, randomized, controlled, observer-blind clinical trial, was to compare the efficacy of the neurostimulator-guided infraclavicular block of the brachial plexus, using two different techniques: multiple injection with localization of three different cords and the single injection technique with localization of the medial cord. Methods. Two hundred and sixty (260) patients scheduled for upper limb surgery under regional anesthesia were randomly distributed into two groups: multiple injection (MI) (129) or single injection (SI) (128). The primary outcome assessed was the efficacy of the block, meaning the absence of sedation beyond some established margins or the need to administer general anesthesia. Other outcomes measured were patient satisfaction and the presence of side effects. Results. Both groups had comparable baseline characteristics. The time for administering the block was 9,6 minutes (±5,9) for SI vs. 10,4 minutes (±3,8) for MI, which was not clinically different. The primary outcome showed 7 failures in 129 MI patients (5,43 %) and 27 (21,09 %) of the SI 128 patients studied. This difference between the two techniques results in a RR of 3,89 with a CI (1,76 - 8,6) and p< 0,0002. Conclusions. In a significant sample of patients and within a controlled environment, the effectiveness of the brachial plexus block using the conventional multiple injections technique with peripheral nerve stimulator was superior to stimulator-guided peripheral nerve single injection technique with localization of the medial cord.