Ultrasonographic Evaluation of Needle Electromyography Insertion Into the Tibialis Posterior Using a Posterior Approach

Abstract Won SJ, Kim JY, Yoon JS, Kim SJ. Ultrasonographic evaluation of needle electromyography insertion into the tibialis posterior using a posterior approach. Objective To estimate the safety window for needle insertion in the posterior approach to the tibialis posterior by ultrasonography, particularly in a clinical setting. Design Cross-sectional study. Setting University hospital. Participants Healthy volunteers (108 legs, from 22 men and 32 women). Interventions Not applicable. Main Outcome Measures Distance between the tibia and neurovascular bundles in the posterior aspect of the tibia on a transverse ultrasonographic scan. Results The safety window at the midpoint was significantly larger than the upper third (0.62–2.16cm, average 1.47±0.38cm vs 0.51–1.62cm, average 1.16±0.31cm). The depth at the midpoint was significantly more shallow than the upper third (1.57–3.16cm, average 2.31±0.34cm vs 1.76–3.66cm, average 2.52±0.38cm). Body weight, height, tibial length, and leg circumference showed positive correlation with the safety window at both points. Conclusions The midpoint may be more favorable than the upper third for needle insertion to the tibialis posterior with a posterior approach.