Tibial nerve block: Supramalleolar or retromalleolar approach? a randomized trial in 110 participants

Abstract

Of the five nerves that innervate the foot, the one in which anesthetic blocking presents the greatest difficulty is the tibial nerve. The aim of this clinical trial was to establish a protocol for two tibial nerve block anesthetic techniques to later compare the anesthetic efficiency of retromalleolar blocking and supramalleolar blocking in order to ascertain whether the supramalleolar approach achieved a higher effective blocking rate. A total of 110 tibial nerve blocks were performed. Location of the injection site was based on a prior ultrasound assessment of the tibial nerve. The block administered was 3 mL of 2% mepivacaine. The two anesthetic techniques under study provided very similar clinical results. The tibial nerve success rate was 81.8% for the retromalleolar technique and 78.2% for the supramalleolar technique. No significant differences in absolute latency time (p = 0.287), percentage of effective nerve blocks (p = 0.634), anesthetic block duration (p = 0.895), or pain level during puncture (p = 0.847) were found between the two techniques. The greater ease in locating the tibial nerve at the retromalleolar approach could suggest that this is the technique of choice for tibial nerve blocking, especially in the case of professionals new to the field. The supramalleolar technique could be worth considering for those more experienced professionals.