Assessment of the Optimal Distal End Length of Echogenic Perineural Catheters to Facilitate Successful Coiling: A Regional Anesthesia Simulator-Based Technical Study

INTRODUCTION: We investigated the optimal length of a flexible end-portion of an echogenic-straight perineural catheter that would facilitate a catheter's flexible distal portion to coil behind the sciatic nerve in a Blue Phantom nerve block simulator (Elevate Healthcare, Sarasota, Florida, United States). METHODS: In 80 20G perineural echogenic catheters, the integral stylet was retracted at various lengths (from 3 cm to 10 cm) so that the optimal catheter's flexible length that enables the catheter's flexible end portion (3-10 cm) to coil could be evaluated. Ten perineural catheters were allocated per cm of retraction. In our binary format, two variables were included: the first was the length of the catheter's distal flexible end, and the second was whether the catheter's distal end was coiled or not coiled. Optimal probabilities (90% and 95%) predicting the catheter's optimal flexible distal length that facilitates successful coiling or not were evaluated by probit regression. RESULTS: