Continuous Popliteal-Sciatic Blocks for Postoperative Analgesia: Traditional Proximal Catheter Insertion Superficial to the Paraneural Sheath Versus a New Distal Insertion Site Deep to the Paraneural Sheath

We tested the hypothesis that during a continuous popliteal-sciatic nerve block, postoperative analgesia is improved with the catheter insertion point "deep" to the paraneural sheath immediately distal to the bifurcation between the tibial and common peroneal branches, compared with the traditional approach "superficial" to the paraneural sheath proximal to the bifurcation. The needle tip location was determined to be accurately located with a fluid bolus visualized with ultrasound; however, catheters were subsequently inserted without a similar fluid injection and visualization protocol (visualized air injection was permitted and usually implemented, but not required per protocol). The average pain (0–10 scale) the morning after surgery for subjects with a catheter inserted at the proximal subparaneural location (n = 31) was a median (interquartile) of 1.5 (0.0–3.5) vs 1.5 (0.0–4.0) for subjects with a catheter inserted at the distal supraparaneural location (n = 32; P = .927). Secondary outcomes were similarly negative. Accepted for publication July 2, 2018. Funding: This work was supported by the Department of Anesthesiology, University California San Diego (San Diego, CA). The authors declare no conflicts of interest. Institutional review board: University of California, San Diego (UCSD) Human Research Protections Program at 9500 Gilman Dr, Mail Code 0052, La Jolla, CA 92093–0052; (858) 657–5100. E-mail: tnelson@ucsd.edu. This report describes human research. This study was conducted with written informed consent from the study subjects. This report describes a prospective randomized clinical trial. The authors state that the report includes every item in the Consolidated Standards of Reporting Trials (CONSORT) checklist for a prospective randomized clinical trial. The study was registered before patient enrollment. This was not an observational clinical study. Registry URL: clinicaltrials.gov NCT02523235. Plain Language Summary: We found no evidence that during a "continuous" popliteal nerve block, postoperative analgesia is improved with the perineural catheter tip deep to the paraneural sheath immediately distal to the sciatic bifurcation, compared with a traditional approach with the catheter tip superficial to the paraneural sheath proximal to the bifurcation. The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the funding entity. Reprints will not be available from the authors. Address correspondence to Brian M. Ilfeld, MD, MS (Clinical Investigation), Department of Anesthesiology, University California, San Diego, 200 W Arbor Dr, MC 8770, San Diego, CA, 92103. Address e-mail to bilfeld@ucsd.edu. © 2018 International Anesthesia Research Society

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