Intraneural Ultrasound-guided Sciatic Nerve Block: Minimum Effective Volume and Electrophysiologic Effects.

What We Already Know About This Topic: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Both extra- and intraneural sciatic injection resulted in significant axonal nerve damage. This study aimed to establish the minimum effective volume of intraneural ropivacaine 1% for complete sensory-motor sciatic nerve block in 90% of patients, and related electrophysiologic variations.

Methods: Forty-seven consecutive American Society of Anesthesiologists physical status I-II patients received an ultrasound-guided popliteal intraneural nerve block following the up-and-down biased coin design.

Effects of the Intraneural and Subparaneural Ultrasound-Guided Popliteal Sciatic Nerve Block: A Prospective, Randomized, Double-Blind Clinical and Electrophysiological Comparison.

Background And Objectives: This prospective, randomized, double-blind study compared the effects of the ultrasound-guided popliteal sciatic nerve block performed by either intraneural or subparaneural approach followed by an electrophysiological evaluation. We hypothesized that intraneural injection provides a faster onset with a better success rate compared with the subparaneural approach.

Methods: Eighty-eight patients were enrolled and randomized to receive an ultrasound-guided popliteal sciatic nerve block injecting 15 mL ropivacaine 1% according to an intraneural injection (group INTRA = 44) or a subparaneural injection (group SUBPARA = 44).