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Updated: Feb 14, 2026

Simulator Training for Endovascular Neurosurgery
Published on: May 6, 2020
Assessment of the Optimal Distal End Length of Echogenic Perineural Catheters to Facilitate Successful Coiling: A
Maria Riga1, Eleni Poulogiannopoulou1, Konstantina Panagouli1
1Second Department of Anesthesiology, National and Kapodistrian University of Athens School of Medicine, Athens, GRC.
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In 80 20G perineural echogenic catheters, the integral stylet was retracted at various lengths (from 3 cm to 10 cm) so that the optimal catheter's flexible length that enables the catheter's flexible end portion (3-10 cm) to coil could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:
Overall, 64 of the 80 perineural catheters were coiled. Analysis showed that withdrawing the integral stylet of a perineural catheter by 7 (6.1-9.4) cm and 8.1 (6.9-11.3) cm resulted in an optimal successful coiling with 90% and 95% probability (p<0.001). Injection of normal saline through the 60 unobstructed catheters contacted with the sciatic nerve in 55 cases (92%).
Conclusion:
Retracting the integral stylet of a perineural catheter by specific lengths facilitates the coiling of its flexible distal end with high probability. This configuration could provide a functional buffer of catheter length, mitigating the risk of tip dislocation from its intended position.
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