Evidence Basis for Ultrasound Guidance for Lower-Extremity Peripheral Nerve Block

Abstract

This article reviews and summarizes randomized controlled studies that have investigated ultrasound guidance (USG) for lower-extremity peripheral nerve blocks in comparison with other peripheral nerve localization techniques and those that compared different ultrasound-guided techniques investigating optimal perineural local anesthetic distribution patterns.Thirty-four studies met the inclusion criteria (minimum Jadad score 3), and 10 additional studies directly compared USG with peripheral nerve stimulation, and 5 additional studies directly compared USG with landmark-based field blocks. Fourteen studies compared different local anesthetic distribution parameters.Analysis of the literature supports the use of USG for decreased block performance time, decreased block onset time, increased rate of complete sensory block, and increased analgesic efficacy. Ultrasound was never inferior to peripheral nerve stimulation. The research focus has evolved during the last 5 years into investigating optimal ultrasound-guided techniques.

The Second American Society of Regional Anesthesia and Pain Medicine Evidence-Based Medicine Assessment of Ultrasound-Guided Regional Anesthesia

“…49,50 With regard to the sciatic popliteal approach, recent investigations consistently demonstrate improved block characteristics (onset time and/or performance time) when the local anesthetic is deposited within the subparaneural compartment (the paraneurium is a sheath deep to the epimysium that surrounds muscle tissue and superficial to the nerve's epineurium). 8,51,52 In summary, an abundance of new lower-extremity studies (mostly level Ib evidence) has served to reinforce our previous grade A recommendation that US improves block characteristics (onset time, performance time, and rate of complete sensory blockade) as compared with PNS techniques. Importantly, US was never found to be inferior to the comparator technique, regardless of the primary outcome studied.…”

“…Specific methodologies for the various components of this project are detailed in the accompanying individual articles. [2][3][4][5][6][7][8][9] In brief, putative evidence was gathered using a variety of standard electronic search engines to identify relevant literature, concentrating on the period from 2009 through spring 2015. The specific search engines used, language limitations, and MeSH (medical subject headings) are described in the individual articles.…”

“…I indicates insufficient or conflicting evidence not allowing a recommendation for or against intervention (eg, optimal perineural local anesthetic distribution or continuous catheter placement). 8 Evidence for US affecting positively the characteristics of all lower-extremity blocks and techniques (eg, femoral, sciatic, single injection, catheter) is somewhat stronger than that for upper-extremity block. Lower-extremity studies were considered positive for US if any outcome was superior to the comparator technique.…”

“…[2][3][4][5][6][7][8][9] Clinicians are encouraged to read these supporting articles for a more complete understanding of the evidence basis for UGRA.…”

Regional anesthesia in pain management

“…Multiple recently published systematic reviews found ultrasound guidance to improve the performance of the blocks and different patient outcomes [11][12][13][14]. Importantly, the expectation that direct visualization of the neural structures would reduce the incidence of neurologic complications has not been confirmed, but ultrasound guidance has been found to reduce the risk of local anesthetic systemic toxicity and possibly pneumothorax [15 & ].…”