Comparison of Interscalene brachial plexus blockade by eliciting multiple point paresthesia and electrical nerve stimulation techniques: a prospective, randomized trial

Abstract

Background: Despite worldwide use of regional blocks, interscalene block has failed to gain widespread acceptance in routine anesthesia practice owing to a higher risk of failure and untoward events. We intend to review its clinical applicability and compare the blockade features using two different techniques.Methods: We evaluated 110 patients of ASA physical status I-III at two centers over 2 years, receiving interscalene brachial plexus block and compared the blockade features of two techniques viz. eliciting paresthesia on multiple points and injecting local anesthetic (group MP, n=55) or injecting total dose of local anesthetic with needle immobilized on a single point after confirming muscular twitches using electrical stimulation at current amplitude of 0.3-0.6 mV (group ES, n=55).Results: Complete success, inadequate block and complete failure of block was observed in [92.7%; 5.45%; 0.9%] cases in MP group and [87.2%; 9%; 1.8%] cases in ES group respectively. The procedural time and time for readiness to surgery was 13±3.5min and 11.4±4.0min in MP group; 6.2±3.0 min and 15±5.6min in ES group p(<0.05). The number of needle pricks and passes was [2.1(1-3); 12 (9-21)] in MP group and [1.2(1-2); 7(5-12)] in ES group (p<0.01). Post-operative neurological dysfunction occurred in 4 cases MP/ES group: 3/1Conclusion: We conclude that either of the techniques is associated with minimal risk of complications and recommend their use in interscalene block depending on choice and experience of attending anesthesiologist.