Update on Ultrasound for Truncal Blocks

Abstract

Since our last review, numerous studies have been published, especially for the paravertebral and transversus abdominis plane blocks, and 3 novel US-guided blocks (Pecs, quadratus lumborum, and transversalis fascia blocks) have been described. Although some of these studies support the use of US for performing these blocks, others do not. Additional studies have used US to improve our understanding of the anatomy pertinent to these blocks and evaluated the effect on patient outcomes and risk of complications.

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

“…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.…”

“…We have also included in this iteration analysis of evidence for newer truncal blocks-PECS, quadratus lumborum, and transversalis fascia-all of which have been described in limited case reports or technical descriptions without comparison to alternative techniques or with insufficient subject numbers to adequately ascertain complication rates or major outcomes. 7 Our 2010 review 53 concluded that limited RCT evidence supported USG as the preferred technique for rectus sheath and II/IH blocks, but evidence was insufficient to make recommendations regarding other blocks. The interval 5-year period has produced a number of anatomic (primarily cadaver based), pharmacokinetic, injectate spread, and feasibility studies, but relatively few studies that compared UGRA with other localization techniques or that assessed complications.…”

“…New cadaveric and volunteer studies have better defined relevant anatomy, pharmacology, and analgesic attributes of TAP blocks. 7 The most important of these studies demonstrated that a 2-injection technique was required to block the entire (unilateral) anterolateral abdominal wall in 8 volunteers. 57 Several metaanalyses in the last 5 years have evaluated the role of TAP blocks in various surgeries, including cesarean delivery.…”

“…[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 & ].…”