Background and Aims Selective supraclavicular nerve and superior trunk blocks are described for clavicle surgeries.1 This series objective was to observe feasibility of selective middle, inferior trunk (MT/IT) and musculocutaneous nerve (MCN) block towards a site specific regional strategy for distal forearm surgery.
Methods After informed consent, 10 patients undergoing distal forearm surgeries underwentselective MT (3 ml), IT (4 ml) and MCN (3 ml) blocks with equal mixture of local anaesthetics (2% Lidocaine and 0.5% Bupivacaine). MT and IT were identified with systematic sign based scanning.2MT was blocked distal to C7 transverse-process where C7 ventral-ramus (VR) appeared multifascicular as hyperechoic honey coomb (Figure 1). The IT was blocked where C8 and T1-VR combined over first rib (Figure 2A&B). Subsequently arm was abducted and MCN blocked at the distal axillary crease (Figure 2C & D). Sensory-motor mapping at 30 minutes, strategy success, requirement of rescue measure, analgesic duration and complications were noted (Table 1).
Results In all patients MT and IT were identified and blocked. At 30 minutes all patients exhibited complete conduction blockade (CCB) in median, ulnar and musculocutaneous nerve. Radial nerve had sensory-motor sparing in 30% patients, however only one patient required rescue block of radial nerve at the elbow, for surgery completion. At the end of surgery 50% of patients had CCB of the axillary nerve as well.
Conclusions Selective MT/IT with MCN block is feasible for surgery proximal to the wrist as well as the medial aspect of hand. Detailed sensory-motor mapping of individual nerves requires further examination to establish site specificity.