Needle tip visualization is fundamental to the safety and efficacy of ultrasound-guided regional anesthesia (UGRA). It can be extremely challenging especially at steep insertion angles. We assessed whether an echogenic needle improved tip visibility during UGRA by anesthesiologists performing their normal in-plane technique. The visibility of the Pajunk Sonoplex (echogenic) and the Pajunk Uniplex (control) needle were compared during 60 nerve blocks (30 femoral, 30 sciatic) in this randomized controlled trial. All ultrasound imaging was recorded for analysis. The anesthesiologist subjectively estimated the percentage time they had visualized the needle tip (5-point scale: 1 [0%-20%], 2 [20%-40%], 3 [40%-60%], 4 [60%-80%], 5 [80%-100%]). The actual time the tip was in view, angle of needle insertion, target depth, and procedure time were subsequently measured objectively by a single investigator. The Sonoplex group had both subjectively and objectively better tip visibility (P=0.002), despite having larger mean body mass index (29.0 vs 25.0 kg/m(2), P=0.01) and steeper mean insertion angle (31 vs 22 degrees, P=0.03). Objective percentage tip visibility, during in-plane UGRA, reduced by 12% for every 10-degree increase in insertion angle with the control. Tip visibility with the Sonoplex was independent of insertion angle over the range studied (0-57 degrees, P=0.95). This finding occurred when nonexpert anesthesiologists performed their standard UGRA technique. A needle that is visible for a greater percentage of time has potential safety and efficacy implications.
Copyright © 2011 by American Society of Regional Anesthesia and Pain Medicine