The Requisites of Needle-to-Nerve Proximity for Ultrasound-Guided Regional Anesthesia

Self Cite

135

Scientific evidence from the past 5 years has clarified and strengthened our understanding of ultrasound-guided regional anesthesia as a nerve localization tool. High-level evidence supports ultrasound guidance contributing to superior characteristics with selected blocks, although absolute differences with the comparator technique are often relatively small (especially for upper-extremity blocks). The clinical meaningfulness of these differences is likely of variable importance to individual practitioners. The use of ultrasound significantly reduces the risk of local anesthetic systemic toxicity as well as the incidence and intensity of hemidiaphragmatic paresis, but has no significant effect on the incidence of postoperative neurologic symptoms. WHAT'S NEW IN THIS UPDATE?: This evidence-based assessment of ultrasound-guided regional anesthesia reviews findings from our 2010 publication and focuses on new meta-analyses, randomized controlled trials, and large case series published since 2009. New to this exercise is an in-depth analysis of the accuracy and reliability of ultrasound guidance for identifying needle-to-nerve relationships. This version no longer addresses ultrasound for interventional pain medicine procedures, because the growth of that field demands separate consideration. Since our 2010 publication, new information has either supported or strengthened our original conclusions. There is no evidence that ultrasound is inferior to alternative nerve localization methods.

Section: Methodsmentioning

confidence: 99%

“…[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.…”

mentioning

confidence: 99%

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

Neal

Brull

Horn

et al. 2016

Self Cite

135

“…Ultrasound guidance allows real-time visualization of the needle-to-nerve relationship, yet, as noted in 2010 and further elucidated in the interim, 93 practitioners must be aware of the technical limitations of US. For instance, US facilitates the early detection of a 0.5-mL intraneural injection into cadaveric sciatic nerve or supraclavicular plexus, as manifested by cross-sectional expansion of the nerve and echogenic changes.…”

Section: Indirect Effects Of Ugra On Patient Safetymentioning

confidence: 99%

Ultrasound-Guided Regional Anesthesia and Patient Safety

Neal¹

2016

226

103

Since the original 2010 publication of this analysis, evidence has continued to support the concept that ultrasound (US) guidance does not meaningfully affect the incidence of peripheral nerve injury (PNI) associated with regional anesthesia. Similar confirmatory evidence attests to US guidance reducing the incidence and intensity of hemidiaphragmatic paresis (HDP) but not eliminating it. Literature published since late 2009 reports the effective role of US guidance in reducing the incidence of local anesthetic systemic toxicity and allows calculation of a lower predicted frequency of pneumothorax associated with US-guided supraclavicular blocks.

“…15 From a technological standpoint, the decreased US visibility associated with deep neural structures constitutes a challenge. For example, Karmakar et al 16 could identify the lumbar plexus in only two-thirds of cases even when using a high-resolution US machine.…”

Section: Limitations Of Ultrasound Guidancementioning

confidence: 99%

Beyond Ultrasound Guidance for Regional Anesthesiology

Tran

Boezaart

Neal

2017

Despite its popularity, ultrasound (US)-guided regional anesthesiology is associated with significant limitations. The latter can be attributed to either the US machine (ie, decreased ability to insonate deep neural structures, as well as the thoracic spine) or the operator. Shortcomings associated with the operator can be explained by errors in perception (ie, ambiguous criteria for needle/catheter tip-to-nerve proximity and subparaneural local anesthetic injection) or interpretation. Perhaps the greatest confusion afflicting US-guided regional anesthesiology originates from an intellectual misconception pertaining to its application. Increasingly, authors are using US to identify interfascial planes where local anesthetic can be injected thereby "discovering" new truncal blocks. Often these novel blocks suffer from a lack of proper randomized, comparative validation.Fortunately, solutions have been proposed to remedy many shortcomings associated with US guidance. The inability of US to reliably insonate deep neural structures can be circumvented with adjunctive neurostimulation. Fluoroscopy and waveform analysis have been proven to increase the success rate of thoracic epidural blocks. For continuous nerve blocks, combined US-neurostimulation may provide an objective end point (ie, an evoked motor response) for neural proximity and subparaneural positioning of the catheter tip. Finally, the solution to the plethora of nonvalidated US-guided blocks is both elegant and simple. New nerve blocks should answer a specific clinical need, and their first descriptions should take the form of an adequately powered, observer-blinded, randomized comparison against the established standard of care or, at the very least, a large case series (eg, a Brief Technical Report).