ASRA Pain Medicine Update

Each year, new Regional Anesthesiology and Acute Pain Medicine (RAAPM) fellows join the 87 RAAPM fellowship programs that are currently listed on the ASRA website in the United States and Canada. We reached out to RAAPM fellowship program directors to provide their favorite articles for fellows and senior anesthesiologists to read. In this ASRA News article, we provide a summary of a few program directors’ top selections. A broader, curated list of 50 articles in the Regional Anesthesia and Acute Pain canon can be found here.

Sites BD, Spence BC, Gallagher JD, et al. Characterizing novice behavior associated with learning ultrasound-guided peripheral regional anesthesia. Reg Anesth Pain Med. 2007;32(2):107-15. PMID 17350520. http://doi.org/10.1016/j.rapm.2006.11.006.

Sites BD, Brull R, Chan VWS, et al. Artifacts and pitfall errors associated with ultrasound-guided regional anesthesia. part ii: a pictorial approach to understanding and avoidance. Reg Anesth Pain Med. 2007;32(5):419-33. PMID 17961842. https://doi.org/10.1097/aap.0b013e3181d3535a.

Sites et al. did the regional anesthesia community a great service in categorizing many of the quality compromising behaviors common to ultrasound-guided regional anesthesia procedures. This is essential reading for learners seeking to anticipate and mitigate common deficiencies, as well as advanced learners and educators seeking to anticipate and overcome practical procedural problems.

For every faculty member who mutters “show me the needle” like it is their personal mantra and every fellow or resident who hears the phrase in their sleep, it is validating to know the most common novice behaviors, by far, in ultrasound-guided regional anesthesia are 1) advancing the needle without seeing the tip and 2) unintentional ultrasound probe movement. Also striking (and liberating for trainees) is that the group observed 520 blocks and catalogued almost 400 quality compromising behaviors (sometimes more than one per block). This gives valuable perspective that small errors are common and should not be a source of embarrassment, but a challenge to overcome.

They also demonstrate, through visual examples and essential clinical pearls, the ultrasound artifacts that all aspiring regional anesthesiologists should recognize and understand.  Though both articles in the Artifacts and Pitfall Errors series are excellent, part II explains many of the phenomena seen routinely in ultrasound-guided regional anesthesia.  Reverberation and resolution artifacts, acoustic shadowing and enhancement, the bayonet sign, and many more are categorized and thoroughly explained with exploration of their clinical significance. This has been a part of my essential readings for budding regional anesthesia trainees for over a decade and it still holds up as the most clear and thorough review on the subject.

Take-Home Points:

Advancing the needle without visualizing the tip and unintentional ultrasound movement are common mistakes that influence block performance. Reverberation, shadowing, and other artifacts commonly encountered in ultrasound-based imaging are properties of ultrasound technology and should be expected and understood.

Selected by: Brian F. S. Allen, MD. Dr. Allen is an assistant professor of anesthesiology at Vanderbilt University in Nashville, TN. 

Memtsoudis SG, Cozowicz C, Bekeris J, et al. Anaesthetic care of patients undergoing primary hip and knee arthroplasty: consensus recommendations from the International Consensus on Anaesthesia-Related Outcomes after Surgery group (ICAROS) based on a systematic review and meta-analysis. British Journal of Anesthesia. 2019;123(3):269-287. PMID: 31351590. https://doi.org/10.1016/j.bja.2019.05.042.

Caring for patients undergoing total joint arthroplasty (TJA) is a foundational part of the clinical practice for regional anesthesiologists.  Fellows in regional anesthesia and acute pain medicine provide anesthetic care for these patients on a daily basis and should be a source of expertise on the topic.  Despite a large number of yearly publications that aim to address the potential benefits of neuraxial anesthesia for TJA, many studies have shortcomings of design, lack of power, and a reliance on retrospective data.  Therefore, a well-constructed meta-analysis that systematically examines the available literature and provides evidence-based recommendations is of great educational value and can guide clinical practice.

The authors sought to compile a systematic review and meta-analysis to compare general anesthesia to neuraxial anesthesia in order to formulate a consensus statement for optimal care of patients undergoing hip and knee arthroplasty.  An international multidisciplinary group of 50 individuals with expertise in care of orthopedic surgery patients reviewed 94 studies spanning a 70-year time period.  The authors looked at numerous perioperative outcomes, including overall mortality, and were able to conclude that neuraxial anesthesia is preferred for both knee and hip arthroplasty, with stronger grade evidence for hip arthroplasty.  While neuraxial anesthesia as the primary anesthetic in patients without contraindications was shown to be beneficial, it did not have a significant effect on all outcomes examined.

The ever-changing nature of surgical techniques for TJA as well as changing practice patterns for both general and neuraxial anesthesia provide a significant limitation for interpretation of data collected over a 70-year period.  The authors suggest that large, multicenter randomized control trials would provide more definitive evidence, but the logistical challenges may preclude such trials from ever being completed.

Take-Home Points:

Neuraxial anesthesia is endorsed by experts for lower extremity TJA based on a systematic review of literature over the last 70 years.

Selected by: Michael Kushelev MD. Dr. Kushelev is an assistant professor of anesthesiology at The Ohio State University Wexner Medical Center in Columbus.

Stiegler MP, Patel N, Vadi MG. Local Anesthetic Systemic Toxicity after Combined Psoas Compartment–Sciatic Nerve Block: Analysis of Decision Factors and Diagnostic Delay. Anesthesiology. 2014; 120, 987-996. PMID: 24694849. https://pubs.asahq.org/anesthesiology/article/120/4/987/11850/Local-Anesthetic-Systemic-Toxicity-after-Combined.

The authors detail a case of local anesthetic systemic toxicity after a combined psoas compartment and sciatic nerve block in an elderly patient with multiple comorbidities undergoing hip fracture repair surgery.  This article is an excellent journal club topic because it is a springboard for discussion with medical students, residents, and fellows about a complex patient with a fatal outcome. It is an opportunity to discuss preoperative workup and planned intraoperative management of a high-risk patient. It brings to light a critical patient safety issue in regional anesthesia and acute pain medicine – local anesthetic systemic toxicity (LAST).  Beyond reviewing the diagnosis and treatment of LAST, the article outlines decision-making variables in challenging situations and provides a framework for diagnostic decisions. Other important topics covered include the use of cognitive aids, crisis resource management and the necessity of situational awareness.

In the discussion section of the article, the authors are to be commended for being willing to publish and discuss a case with a difficult outcome with the goal to better educate the reader. As the authors state, “Confronting diagnostic errors, openly discussing adverse events, and formulating recommendations for quality improvement are all critical to limiting future errors and improving overall patient safety.”  This article offers a space for each learner to critically think, “What would I/we do?” “How would we manage this patient?” and “Would the outcome have been different if LAST has been identified sooner?”  These are questions that help everyone grow as a learner and as a team.

Take-Home Points:

Selected by: Danielle B. Ludwin, MD. Dr. Ludwin is an associate professor of anesthesiology at Columbia University Irving Medical Center in New York, NY.

Rigg JR, Jamrozik K,  Myles PS, et al. Epidural anaesthesia and analgesia and outcome of major surgery. Lancet. 2002;359:1276-82. PMID: 11965272. https://doi.org/10.1016/s0140-6736(02)08266-1 

Park WY, Thompson JS, Lee KK. Effect of epidural anesthesia and analgesia on perioperative outcome. Annals of Surgery. 2001;234:560-569. PMID: 11573049. https://doi.org/10.1097/00000658-200110000-00015

Dr. Rigg and the international MASTER trial, along with Dr. Park and his trial of epidural analgesia at Veterans Affairs hospitals in the United States, provide randomized evidence on the impact of epidural analgesia on postoperative outcomes. They help address the larger question of: What does the evidence show with regard to the effect of epidural anesthesia and analgesia on postoperative morbidity and mortality? Do we place epidurals for pain management only or do they help patients avoid major complications? These two classic articles provide a great background for this important discussion, as the evidence is complex. Rigg and the MASTER trial found a decreased incidence of respiratory failure (23% vs 30%, number needed to treat = 15) in the group randomized to an epidural compared to those without neuraxial anesthesia. Park and colleagues found a benefit with regard to major morbidity and duration of mechanical ventilation in open aortic surgery patients with an epidural, but only opioids were infused via the epidural postoperatively. These two articles lay the framework for a great journal club on both why we use epidurals and how their use can and should be studied.

Take-Home Points:

What does it mean to place an epidural and are they all created equal? Superior pain control and a decrease in respiratory failure in some randomized trials are helpful for teaching, as are a critical evaluation of RA vs GA study design.

Selected by: Steven B. Porter, MD. Dr. Porter is an assistant professor of anesthesiology at Mayo Clinic Florida in Jacksonville.

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Tran DQ, Salinas FV, Benzon HT, Neal JM. Lower extremity regional anesthesia: essentials of our current understanding. Reg Anesth Pain Med. 2019;44:143-180. https://doi.org/10.1136/rapm-2018-000019.

An in-depth understanding of anatomy is crucial to performing safe and effective regional anesthesia.  In their article, DQ Tran and colleagues meticulously describe the anatomy of the lumbar and lumbosacral plexus, pointing out clinically salient facts in order to assist the proceduralist in better understanding the trajectories and surrounding structures of the nerves innervating the lower extremity, the sensory and motor distributions of these nerves, and the microstructure of these nerves.

This comprehensive (and updated) review of regional anesthesia for the lower extremity is written by leaders in our field and is a concise, poignant review of the terminal nerves (femoral nerve, obturator nerve, lateral femoral cutaneous nerve, posterior tibial, common peroneal, posterior femoral cutaneous nerves) and the adductor canal. By better understanding the locations of the nerves and their terminal branches, perhaps the proceduralist will better recognize the optimal target location for deposition of local anesthetic and the extent to which a specific nerve block will cover.

The authors also describe where the articular branches to the hip and knee joint are derived from, outcomes of different techniques and approaches for lower joint replacement surgery and for hip fractures, different effects of adjuvants to local anesthetics, local anesthetic dosing, as well as complications and side effect profiles specific to regional anesthesia of the lower extremity.

Take-Home Points:

This excellent primer on lower extremity neuroanatomy explores multiple techniques, including efficacy and outcomes. This article can also serve as a point of reference for additional ‘deep dives’ as the fellow progresses in knowledge and experience.

Selected by: Linda Le-Wendling, MD. Dr. Le-Wendling is an associate professor of anesthesiology at the University of Florida in Gainesville.

Støving K, Rothe C, Rosenstock CV, Aasvang EK, Lundstrøm LH, Lange KHW. Cutaneous Sensory Block Area, Muscle-Relaxing Effect, and Block Duration of the Transversus Abdominis Plane Block: A Randomized, Blinded, and Placebo-Controlled Study in Healthy Volunteers. Reg Anesth Pain Med. 2015;40(4):355-62. PMID: 25923818. https://doi.org/10.1097/aap.0000000000000252.

Chen Y, Shi K, Xia Y, Zhang X, Papadimos TJ, Xu X, Wang Q. Sensory Assessment and Regression Rate of Bilateral Oblique Subcostal Transversus Abdominis Plane Block in Volunteers. Reg Anesth Pain Med. 2018;43(2):174-179. PMID: 29278604. https://doi.org/10.1097/aap.0000000000000715.

These two studies used healthy volunteers to determine various characteristics of the transversus abdominis plane (TAP) block. One study measured these characteristics after performing a TAP block with a traditional needle approach, where the needle target lies superior to the iliac crest. The other study measured characteristics after performing the TAP block with a subcostal approach, where the needle target lies inferior to the costal margin.

Important data points included sensory block duration, muscle relaxation effect, dermatomal distribution of sensory change, and visual drawings outlining the areas of sensory changes on the abdomen. As expected, most healthy volunteers reported a sensory change within the T7-L1 dermatomal distribution, and this change lasted between 8-12 hours. Interestingly, the precise areas of sensory change along the surface area of the abdomen were highly variable between participants. The visual drawings demonstrated more consistent and centralized sensory change in those who received the TAP block via a subcostal approach.

Take-Home Points:

The subcostal approach to the TAP block produces a more reliable sensory change than the traditional TAP approach.

Selected by: Bryant W. Tran, MD. Dr. Tran is  an assistant professor of anesthesiology at Virginia Commonwealth University in Richmond.

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Feigl GC, Litz RJ, Marhofer P. Anatomy of the brachial plexus and its implications for daily clinical practice: regional anesthesia is applied anatomy. Reg Anesth Pain Med. 2020 Aug; 45(8):620-627.  PMID: 32471922. https://doi.org/10.1136/rapm-2020-101435.

Karmakar MK, Pakpirom J, Songthamwat B, et al. High definition ultrasound imaging of the individual elements of the brachial plexus above the clavicle. Reg Anesth Pain Med. 2020 May; 45(5):344-350.  PMID: 32102798. https://doi.org/10.1136/rapm-2019-101089.

The effectiveness and safety of regional anesthesia are contingent on our detailed understanding of topographical, anatomical, and sonographic applied anatomy.  These articles are meant to be reviewed as a series.  Together, they expand our contemporary understanding of the brachial plexus.  These authors introduce novel nomenclature such as the interscalene gap space, organization of the ventral rami units, and various fascial anatomy in this region.  They also clarify misnomers such as the  “brachial plexus sheath.”  Feighl et al discuss several nerves, vessels, and elements that are not traditionally elucidated in textbooks.  These include prevertebral fascia, cervical plexus nerves, long thoracic nerve, dorsal scapular nerve, supraclavicular nerve, dorsal scapular artery, subclavius muscle, and pectoral nerves.  In addition, the Marhofer group propose that there are costopleurovertebral ligaments that might prevent local anesthetic spread to the inferior trunk in a classical “corner pocket” supraclavicular nerve block approach.  To reinforce these functional landmark and architecture, the Karmakar group takes us on a high-definition ultrasound imaging adventure that begins inferiorly at the supraclavicular fossa and ends superiorly at the interscalene groove in 5 healthy volunteers.  Some of the pictures depicted in their work provide incredible features and unique insights into applied anatomy in this area.   

Take-Home Points:

As in the DQ Tran et al. paper discussed above, anyone approaching regional anesthesia of the upper extremity can use these papers as a jump-off point for advancing knowledge of critical anatomy of upper extremity peripheral nerves. In the future, high definition ultrasound may allow us to more readily discern needle-nerve interactions.

Selected by: Yan Lai, MD. Dr. Lai is an assistant professor of anesthesiology at Mt. Sinai Medical Center in New York, NY.

Mary Hargett is the director of Education and Clinical Initiatives at the Hospital for Special Surgery in New York, NY.