Systematic Reviews and Meta-analyses in Regional Anesthesia and Pain Medicine (Part I): Guidelines for Preparing the Review Protocol.

Comprehensive resources exist on how to plan a systematic review and meta-analysis. The objective of this article is to provide guidance to authors preparing their systematic review protocol in the fields of regional anesthesia and pain medicine. The focus is on systematic reviews of health care interventions, with or without an aggregate data meta-analysis. We describe and discuss elements of the systematic review methodology that review authors should prespecify, plan, and document in their protocol before commencing the review. Importantly, authors should explain their rationale for planning their systematic review and describe the PICO framework-participants (P), interventions (I), comparators (C), outcomes (O)-and related elements central to constructing their clinical question, framing an informative review title, determining the scope of the review, designing the search strategy, specifying the eligibility criteria, and identifying potential sources of heterogeneity. We highlight the importance of authors defining and prioritizing the primary outcome, defining eligibility criteria for selecting studies, and documenting sources of information and search strategies. The review protocol should also document methods used to evaluate risk of bias, quality (certainty) of the evidence, and heterogeneity of results. Furthermore, the authors should describe their plans for managing key data elements, the statistical construct used to estimate the intervention effect, methods of evidence synthesis and meta-analysis, and conditions when meta-analysis may not be possible, including the provision of practical solutions. Authors should provide enough detail in their protocol so that the readers could conduct the study themselves.

Systematic Reviews and Meta-analyses in Regional Anesthesia and Pain Medicine (Part II): Guidelines for Performing the Systematic Review.

In Part I of this series, we provide guidance for preparing a systematic review protocol. In this article, we highlight important steps and supplement with exemplars on conducting and reporting the results of a systematic review. We suggest how authors can manage protocol violations, multiplicity of outcomes and analyses, and heterogeneity. The quality (certainty) of the evidence and strength of recommendations should follow the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. It is our goal that Part II of this series provides valid guidance to authors and peer reviewers who conduct systematic reviews to adhere to important constructs of transparency, structure, reproducibility, and accountability. This will likely result in more rigorous systematic reviews being submitted for publication to the journals like Regional Anesthesia & Pain Medicine and Anesthesia & Analgesia .

Quality of Recovery After Breast Surgery: A Multicenter Randomized Clinical Trial Comparing Pectoral Nerves Interfascial Plane (Pectoral Nerves II) Block With Surgical Infiltration.

BACKGROUND: Pectoral nerves (PECS II) block is a popular regional analgesia technique for breast surgery. PECS II block or local infiltration by surgeon may improve outcomes including quality of recovery (QoR). METHODS: In this multicenter randomized clinical trial, 104 female patients undergoing breast surgery received: (1) PECS II block with local anesthetic and surgical infiltration with 0.9% saline (PECS group) or (2) PECS II block with 0.9% saline and surgical infiltration with local anesthetic (infiltration group). Patients, anesthetists, surgeons, nursing staff, and research assistants were blinded to group allocation. Patients received standardized general anesthesia and multimodal analgesia. The primary outcome was the global score (maximum score, 150; good recovery, 118) of the multidimensional (pain, comfort, independence, psychological, emotional) QoR-15 questionnaire measured 24 hours postoperatively. Secondary outcomes were pain, and its functional interference measured 24 hours and 3 months postoperatively using the Brief Pain Inventory (BPI) short form (0, optimal; 120, worst possible). Randomly assigned groups were compared on outcomes using the Wilcoxon rank-sum test, and the results were reported as median difference with 95% confidence interval. RESULTS: One hundred eight patients were recruited from August 17, 2016 to June 8, 2018, and 4 patients were withdrawn. Twelve patients from 104 had mastectomy, with the remainder having less invasive surgery. Baseline QoR-15 global scores reported as median [quartiles] were 135 [129, 143] in the PECS group and 139 [127, 143] in the infiltration group. The 24-hour QoR-15 global score reported as median [quartiles] was 131 [116, 140] in the PECS group and 123 [117, 143] in the infiltration group (P = .60), with median difference (95% confidence interval) of -2 (-9 to 5). The median difference reported as infiltration minus PECS for QoR-15 domains was pain 0 (-2 to 1), physical comfort -1 (-3 to 2), physical independence 0 (-2 to 1), psychological support 0 (0-0), and emotions 0 (-1 to 2) (P > .28). The BPI pain subscale at 24 hours (0-40, lower score indicates less pain), reported as median [quartiles], was 7 [2, 13] in the PECS group and 10 [5, 17] in the infiltration group (P = .15). The BPI global score at 24 hours, reported as median [quartiles], was 20 [7, 36] in the PECS group and 23 [10, 43] in the infiltration group (P = .34) and at 3 months was 0 [0, 14] and 0 [0, 11] (P = .85). CONCLUSIONS: After mostly minor surgery for breast cancer, PECS II block was not superior to local infiltration by the surgeon.

A pilot randomized-controlled trial evaluating the erector spinae plane block in thoracic and breast surgery.

PURPOSE: This pilot study evaluated the feasibility of investigating the effect of the erector spinae plane (ESP) block on the patient-centred outcomes of quality of recovery-15 (QoR-15), and brief pain inventory (BPI) in thoracic and breast surgery patients. METHODS: In this randomized-controlled pilot trial, 82 patients undergoing video-assisted thoracoscopic surgery (n = 77) and mastectomy (n = 5) received either continuous ESP block with ropivacaine (ropivacaine group) or the same procedure with 0.9% saline (saline group). All patients received surgical intercostal block (thoracic surgery) or local anesthetic infiltration (breast surgery). Feasibility as the primary outcome was evaluated on recruitment (three patients per week), catheter retention (above 90% at 24 hr), and patient attrition (less than 10%). Secondary outcomes comprised of QoR-15, BPI, and opioid consumption. RESULTS: Recruitment rate was 1.8 patients per week. Catheters were retained in 77 patients (94%) at 24 hr. At three months, five patients were lost to follow-up (6%). At 24 hr compared with baseline, the ropivacaine group had a smaller decline in QoR-15 score (median difference, 14; 95% confidence interval [CI], 2 to 26; P = 0.02) and a smaller increase in BPI global score (median difference, 14; 95% CI, 0 to 24; P = 0.048). There was no difference in opioid consumption (P = 0.08). CONCLUSIONS: In this pilot study, the target recruitment rate was not met, but catheter retention and patient attrition rates were both satisfactory. A definitive trial with QoR-15 as the primary outcome would require 300 study participants. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ID12618000701224); registered 30 April 2018.

RéSUMé: OBJECTIF: Cette étude pilote a évalué la faisabilité d'explorer l'effet d'un bloc du plan des muscles érecteurs du rachis sur des résultats centrés sur le patient, soit la qualité de récupération (QoR-15) et le Questionnaire concis de la douleur (QCD ou BPI 'Brief Pain Inventory'), chez les patients de chirurgie thoracique et mammaire. MéTHODE: Dans cette étude pilote randomisée contrôlée, 82 patients subissant une chirurgie thoracoscopique (n = 77) ou une mastectomie (n = 5) ont reçu soit un bloc continu du plan des muscles érecteurs du rachis avec de la ropivacaïne (groupe ropivacaïne), ou la même intervention avec une solution saline à 0,9 % (groupe salin). Tous les patients ont reçu un bloc intercostal chirurgical (chirurgie thoracique) ou une infiltration d'anesthésique local (chirurgie mammaire). La faisabilité a été évaluée par les critères de recrutement (trois patients par semaine), de la rétention du cathéter (plus de 90 % à 24 h), et du taux d'attrition des patients (moins de 10 %). Les critères d'évaluation secondaires comportaient la QoR-15, le QCD et la consommation d'opioïdes. RéSULTATS: Le taux de recrutement était de 1,8 patients par semaine. Les cathéters sont restés en place chez 77 patients (94 %) à 24 h. À trois mois, cinq patients ont été perdus au suivi (6 %). Après 24 h, par rapport aux valeurs de base, le groupe ropivacaïne présentait un déclin plus léger du score de QoR-15 (différence médiane, 14; intervalle de confiance [IC] 95 %, 2 à 26; P = 0,02) ainsi qu'une augmentation moindre du score global de QCD (différence médiane, 14; IC 95 %, 0 à 24; P = 0,048). Aucune différence n'a été observée en matière de consommation d'opioïdes (P = 0,08). CONCLUSION: Dans cette étude pilote, le taux de recrutement cible n'a pas été atteint, mais les taux de rétention des cathéters et d'attrition des patients étaient tous deux satisfaisants. Une étude définitive de la QoR-15 en tant que critère d'évaluation principal nécessiterait le recrutement de 300 participants. ENREGISTREMENT DE L'éTUDE: Australian New Zealand Clinical Trials Registry (ID12618000701224); enregistrée le 30 avril 2018.

Ultrasound-guided blocks for cardiovascular surgery: which block for which patient?

PURPOSE OF REVIEW: Regional anesthesia blocks may benefit patients undergoing cardiovascular surgery. This review coincides with the evolution of ultrasound-guided fascial plane blocks, societal concerns regarding opioid misuse and changing expectations regarding surgical recovery. RECENT FINDINGS: Paravertebral block and thoracic epidural analgesia have comparable postoperative analgesic profiles following thoracotomy; however, the former has a more favorable complication profile. Limited trials have compared these modalities in cardiac surgery. The mechanism of action of continuous paravertebral blockade may be systemic. Bilateral continuous paravertebral (and other continuous peripheral nerve blocks) should be used with caution in adult patients having cardiac surgery because of the risk of systemic local anesthetic toxicity and bleeding. Novel ultrasound-guided blocks: erector spinae, serratus anterior, pectoral, transversus thoracic muscle and pecto-intercostal fascial plane blocks potentially reduce postoperative opioid requirements; however, they require further investigation before their routine use can be recommended in adult cardiovascular surgical practice. The mechanism of action of erector spinae block is not fully elucidated. SUMMARY: Ultrasound-guided fascial plane blocks may reduce postoperative opioid requirements. Investigation into the safety and efficacy of bilateral continuous ultrasound-guided blockade for cardiac surgery is required. Trial protocols should be embedded into enhanced recovery after surgery programs. Patient-reported and long-term outcomes are recommended.

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.

BACKGROUND: Evidence-based international expert consensus regarding anaesthetic practice in hip/knee arthroplasty surgery is needed for improved healthcare outcomes. METHODS: The International Consensus on Anaesthesia-Related Outcomes after Surgery group (ICAROS) systematic review, including randomised controlled and observational studies comparing neuraxial to general anaesthesia regarding major complications, including mortality, cardiac, pulmonary, gastrointestinal, renal, genitourinary, thromboembolic, neurological, infectious, and bleeding complications. Medline, PubMed, Embase, and Cochrane Library including Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, NHS Economic Evaluation Database, from 1946 to May 17, 2018 were queried. Meta-analysis and Grading of Recommendations Assessment, Development and Evaluation approach was utilised to assess evidence quality and to develop recommendations. RESULTS: The analysis of 94 studies revealed that neuraxial anaesthesia was associated with lower odds or no difference in virtually all reported complications, except for urinary retention. Excerpt of complications for neuraxial vs general anaesthesia in hip/knee arthroplasty, respectively: mortality odds ratio (OR): 0.67, 95% confidence interval (CI): 0.57-0.80/OR: 0.83, 95% CI: 0.60-1.15; pulmonary OR: 0.65, 95% CI: 0.52-0.80/OR: 0.69, 95% CI: 0.58-0.81; acute renal failure OR: 0.69, 95% CI: 0.59-0.81/OR: 0.73, 95% CI: 0.65-0.82; deep venous thrombosis OR: 0.52, 95% CI: 0.42-0.65/OR: 0.77, 95% CI: 0.64-0.93; infections OR: 0.73, 95% CI: 0.67-0.79/OR: 0.80, 95% CI: 0.76-0.85; and blood transfusion OR: 0.85, 95% CI: 0.82-0.89/OR: 0.84, 95% CI: 0.82-0.87. CONCLUSIONS: Recommendation: primary neuraxial anaesthesia is preferred for knee arthroplasty, given several positive postoperative outcome benefits; evidence level: low, weak recommendation. RECOMMENDATION: neuraxial anaesthesia is recommended for hip arthroplasty given associated outcome benefits; evidence level: moderate-low, strong recommendation. Based on current evidence, the consensus group recommends neuraxial over general anaesthesia for hip/knee arthroplasty. TRIAL REGISTRY NUMBER: PROSPERO CRD42018099935.

Impact of Local Infiltration Analgesia on the Quality of Recovery After Anterior Total Hip Arthroplasty: A Randomized, Triple-Blind, Placebo-Controlled Trial.

BACKGROUND: Local infiltration analgesia (LIA) is commonly used in anterior total hip arthroplasty (THA) surgery; however, evidence for its efficacy is lacking. We hypothesized that LIA with 0.2% ropivacaine when compared with injection of placebo (0.9% saline) would improve patient quality of recovery on postoperative day (POD) 1, as measured by the Quality of Recovery-15 (QoR-15) score. METHODS: Patients scheduled to have a primary unilateral anterior THA with a single surgeon in a tertiary level metropolitan hospital were randomized to receive LIA with either 2.5 mL/kg of 0.2% ropivacaine or 0.9% saline as placebo. Patients and clinical and study personnel were blinded to group allocation. Perioperative care was standardized and this included spinal anesthesia and oral multimodal analgesia. The primary outcome was a multidimensional (pain, physical comfort, physical independence, emotions, and psychological support) patient-reported quality of recovery scale, QoR-15, measured on POD 1. RESULTS: One hundred sixty patients were randomized; 6 patients were withdrawn after randomization and 2 patients had incomplete outcome data. The intention-to-treat analysis included 152 patients. The median (interquartile range [IQR]) QoR-15 score on POD 1 of the ropivacaine group was 119.5 (102-124), compared with the placebo group which had a median (IQR) of 115 (98-126). The median difference of 2 (95% confidence interval [CI], -4 to 7; P = .56) was not statistically or clinically significant. An as-per-protocol sensitivity analysis of 146 patients who received spinal anesthesia without general anesthesia, and the allocated intervention, also showed no evidence of a significant difference between groups. Secondary outcomes (worst pain numerical rating scale at rest and with movement on POD 1, opioid consumption on PODs 1 and 2, mobilization on POD 1, Brief Pain Inventory severity and interference on POD 90, and length of stay) were similar in both groups. CONCLUSIONS: LIA with 0.2% ropivacaine when compared with 0.9% saline as placebo did not improve quality of recovery 1 day after anterior THA.

Did ultrasound fulfill the promise of safety in regional anesthesia?

PURPOSE OF REVIEW: Ultrasound guidance has become the accepted standard of practice for peripheral regional anesthesia. Despite evidence supporting the efficacy of ultrasound-guided regional anesthesia, its impact on patient safety has been less clear. RECENT FINDINGS: Evidence has been consistent that ultrasound guidance reduces the incidence of vascular injury, local anesthetic systemic toxicity, pneumothorax and phrenic nerve block. Within the limited global scope of the epidemiology and etiologic complexity of perioperative (including block-related) peripheral nerve injury, there has not been consistent evidence that ultrasound guidance is associated with a reduced incidence of nerve injury. However, a recently published retrospective cohort study has demonstrated that the incidence of short-term nerve injury was decreased with ultrasound guidance compared with nerve stimulation. Ultrasound has led to development of novel blocks, approaches and refinement of existing ones, which may contribute to patient safety. SUMMARY: Ultrasound has revolutionized the way we approach regional anesthesia and contributed to patient safety. It is important to note that patient safety does not hinge on one single technology. Patient safety in regional anesthesia relies on a well trained practitioner to pay meticulous attention to indication, block and patient selection, anatomy, pharmacology, equipment and technique.

Neuraxial and Combined Neuraxial/General Anesthesia Compared to General Anesthesia for Major Truncal and Lower Limb Surgery: A Systematic Review and Meta-analysis.

Neuraxial anesthesia may improve perioperative outcomes when compared to general anesthesia; however, this is controversial. We performed a systematic review and meta-analysis using randomized controlled trials and population-based observational studies identified in MEDLINE, PubMed, and EMBASE from 2010 to May 31, 2016. Studies were included for adult patients undergoing major surgery of the trunk and lower extremity that reported: 30-day mortality (primary outcome), cardiopulmonary morbidity, surgical site infection, thromboembolic events, blood transfusion, and resource use. Perioperative outcomes were compared with general anesthesia for the following subgroups: combined neuraxial-general anesthesia and neuraxial anesthesia alone. Odds ratios (ORs) and 99% confidence intervals (CIs) were calculated to identify the impact of anesthetic technique on outcomes. Twenty-seven observational studies and 11 randomized control trials were identified. This analysis comprises 1,082,965 records from observational studies or databases and 1134 patients from randomized controlled trials. There was no difference in 30-day mortality identified when combined neuraxial-general anesthesia was compared with general anesthesia (OR 0.88; 99% CI, 0.77-1.01), or when neuraxial anesthesia was compared with general anesthesia (OR 0.98; 99% CI, 0.92-1.04). When combined neuraxial-general anesthesia was compared with general anesthesia, combined neuraxial-general anesthesia was associated with a reduced odds of pulmonary complication (OR 0.84; 99% CI, 0.79-0.88), surgical site infection (OR 0.93; 99% CI, 0.88-0.98), blood transfusion (OR 0.90; 99% CI, 0.87-0.93), thromboembolic events (OR 0.84; 99% CI, 0.73-0.98), length of stay (mean difference -0.16 days; 99% CI, -0.17 to -0.15), and intensive care unit admission (OR 0.77; 99% CI, 0.73-0.81). For the combined neuraxial-general anesthesia subgroup, there were increased odds of myocardial infarction (OR 1.18; 99% CI, 1.01-1.37). There was no difference identified in the odds of pneumonia (OR 0.94; 99% CI, 0.87-1.02) or cardiac complications (OR 1.04; 99% CI, 1.00-1.09) for the combined neuraxial-general anesthesia subgroup. When neuraxial anesthesia was compared to general anesthesia, there was a decreased odds of any pulmonary complication (OR 0.38; 99% CI, 0.36-0.40), surgical site infection (OR 0.76; 99% CI, 0.71-0.82), blood transfusion (OR 0.85; 99% CI, 0.82-0.88), thromboembolic events (OR 0.79; 99% CI, 0.68-0.91), length of stay (mean difference -0.29 days; 99% CI, -0.29 to -0.28), and intensive care unit admission (OR 0.50; 99% CI, 0.48-0.53). There was no difference in the odds of cardiac complications (OR 0.99; 99% CI, 0.94-1.03), myocardial infarction (OR 0.91; 99% CI, 0.81-1.02), or pneumonia (OR 0.92; 99% CI, 0.84-1.01). Randomized control trials revealed no difference in requirement for blood transfusion (RR 1.05; 99% CI, 0.65-1.71) and a decreased length of stay (mean difference -0.15 days; 99% CI, -0.27 to -0.04). Neuraxial anesthesia when combined with general anesthesia or when used alone was not associated with decreased 30-day mortality. Neuraxial anesthesia may improve pulmonary outcomes and reduce resource use when compared with general anesthesia. However, because observational studies were included in this analysis, there is a risk of residual confounding and therefore these results should be interpreted with caution.

Wrong-site regional anesthesia: review and recommendations for prevention?

PURPOSE OF REVIEW: Wrong-site regional anesthetic procedures are considered never events. The purpose of this review is to describe the phenomenon of wrong-site regional anesthetic blocks and identify preventive strategies. RECENT FINDINGS: The incidence of wrong-site block may be as frequent as 7.5 per 10,000 procedures. Factors contributing to wrong-site block include physician distraction, patient position change, scheduling changes, inadequate documentation, poor communication, lack of surgical consent, site marking not visible, inadequate supervision, reduced situational awareness, fatigue, cognitive overload, perceived time pressure, delay from World Health sign-in to block performance and omission of block time-out or block time-out occurring before final patient positioning. The American Society of Regional Anesthesia and Pain Medicine have created a 9-point checklist for regional anesthesia procedures. SUMMARY: Preoperative site verification and surgical site marking are mandatory. A time-out should occur immediately before any invasive procedure. Confirming the correct patient and block site with a time-out should occur immediately before all regional anesthetic procedures. If more than one block is performed on one patient, it is recommended that time-out be repeated each time the patient position is changed or separated in time or performed by a different team. The anesthetic team should uniformly implement robust guidelines and checklists to reduce the occurrence of wrong-site regional anesthetic procedures.

Systematic reviews and meta-analyses in regional anesthesia and pain medicine (Part II): guidelines for performing the systematic review.

In Part I of this series, we provide guidance for preparing a systematic review protocol. In this article, we highlight important steps and supplement with exemplars on conducting and reporting the results of a systematic review. We suggest how authors can manage protocol violations, multiplicity of outcomes and analyses, and heterogeneity. The quality (certainty) of the evidence and strength of recommendations should follow the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. It is our goal that Part II of this series provides valid guidance to authors and peer reviewers who conduct systematic reviews to adhere to important constructs of transparency, structure, reproducibility, and accountability. This will likely result in more rigorous systematic reviews being submitted for publication to the journals like Regional Anesthesia & Pain Medicine and Anesthesia & Analgesia.

Systematic reviews and meta-analyses in regional anesthesia and pain medicine (Part I): guidelines for preparing the review protocol.

Comprehensive resources exist on how to plan a systematic review and meta-analysis. The objective of this article is to provide guidance to authors preparing their systematic review protocol in the fields of regional anesthesia and pain medicine. The focus is on systematic reviews of healthcare interventions, with or without an aggregate data meta-analysis. We describe and discuss elements of the systematic review methodology that review authors should prespecify, plan, and document in their protocol before commencing the review. Importantly, authors should explain their rationale for planning their systematic review and describe the PICO framework-participants (P), interventions (I),comparators (C), outcomes (O)-and related elements central to constructing their clinical question, framing an informative review title, determining the scope of the review, designing the search strategy, specifying the eligibility criteria, and identifying potential sources of heterogeneity. We highlight the importance of authors defining and prioritizing the primary outcome, defining eligibility criteria for selecting studies, and documenting sources of information and search strategies. The review protocol should also document methods used to evaluate risk of bias, quality (certainty) of the evidence, and heterogeneity of results. Furthermore, the authors should describe their plans for managing key data elements, the statistical construct used to estimate the intervention effect, methods of evidence synthesis and meta-analysis, and conditions when meta-analysis may not be possible, including the provision of practical solutions. Authors should provide enough detail in their protocol so that the readers could conduct the study themselves.

Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of upper and lower limb nerve blocks.

BACKGROUND: Inconsistent nomenclature and anatomical descriptions of regional anesthetic techniques hinder scientific communication and engender confusion; this in turn has implications for research, education and clinical implementation of regional anesthesia. Having produced standardized nomenclature for abdominal wall, paraspinal and chest wall regional anesthetic techniques, we aimed to similarly do so for upper and lower limb peripheral nerve blocks. METHODS: We performed a three-round Delphi international consensus study to generate standardized names and anatomical descriptions of upper and lower limb regional anesthetic techniques. A long list of names and anatomical description of blocks of upper and lower extremities was produced by the members of the steering committee. Subsequently, two rounds of anonymized voting and commenting were followed by a third virtual round table to secure consensus for items that remained outstanding after the first and second rounds. As with previous methodology, strong consensus was defined as ≥75% agreement and weak consensus as 50%-74% agreement. RESULTS: A total of 94, 91 and 65 collaborators participated in the first, second and third rounds, respectively. We achieved strong consensus for 38 names and 33 anatomical descriptions, and weak consensus for five anatomical descriptions. We agreed on a template for naming peripheral nerve blocks based on the name of the nerve and the anatomical location of the blockade and identified several areas for future research. CONCLUSIONS: We achieved consensus on nomenclature and anatomical descriptions of regional anesthetic techniques for upper and lower limb nerve blocks, and recommend using this framework in clinical and academic practice. This should improve research, teaching and learning of regional anesthesia to eventually improve patient care.

Neurologic complications of regional anesthesia.

PURPOSE OF REVIEW: Regional anesthesia is evolving rapidly and increasing in popularity as evidenced by the large number of publications on the topic. In this healthcare environment, continual assessment of the safety and efficacy of clinical practice is critical. Neurologic complications of regional anesthesia can result in disability and are feared by patients and clinicians. Ultrasound guidance is unique as a nerve localizing technique in terms of being able to image needle-nerve proximity and potentially prevent direct trauma to nerves. This article reviews the recent literature relevant to neurologic complications of regional anesthesia. RECENT FINDINGS: The incidence of intraneural injection during regional anesthesia is higher than previously appreciated. Defining intraneural injection and its significance are the subject of current debate. Clinical studies with small sample sizes suggest that intraneural injection may not necessarily be responsible for nerve injury. Inflammatory mechanisms may contribute to perioperative nerve injury. Ultrasound guidance has not been proven to reduce the incidence of nerve injury due to peripheral nerve blockade (PNB). Increased utilization of PNB is not associated with an increase in perioperative nerve injury. SUMMARY: The pathogenesis of perioperative nerve injury is complex with multiple potential etiologies and mechanisms. The role of intraneural injections as a modifiable risk factor for neurologic complications due to regional anesthesia remains topical. Relevant publications include studies on the morphology of peripheral nerves and risk of perioperative nerve injury in the context of both neuraxial anesthesia and PNB.

Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of abdominal wall, paraspinal, and chest wall blocks.

BACKGROUND: There is heterogeneity in the names and anatomical descriptions of regional anesthetic techniques. This may have adverse consequences on education, research, and implementation into clinical practice. We aimed to produce standardized nomenclature for abdominal wall, paraspinal, and chest wall regional anesthetic techniques. METHODS: We conducted an international consensus study involving experts using a three-round Delphi method to produce a list of names and corresponding descriptions of anatomical targets. After long-list formulation by a Steering Committee, the first and second rounds involved anonymous electronic voting and commenting, with the third round involving a virtual round table discussion aiming to achieve consensus on items that had yet to achieve it. Novel names were presented where required for anatomical clarity and harmonization. Strong consensus was defined as ≥75% agreement and weak consensus as 50% to 74% agreement. RESULTS: Sixty expert Collaborators participated in this study. After three rounds and clarification, harmonization, and introduction of novel nomenclature, strong consensus was achieved for the names of 16 block names and weak consensus for four names. For anatomical descriptions, strong consensus was achieved for 19 blocks and weak consensus was achieved for one approach. Several areas requiring further research were identified. CONCLUSIONS: Harmonization and standardization of nomenclature may improve education, research, and ultimately patient care. We present the first international consensus on nomenclature and anatomical descriptions of blocks of the abdominal wall, chest wall, and paraspinal blocks. We recommend using the consensus results in academic and clinical practice.

Ultrasound-guided thoracic paravertebral blockade: a cadaveric study.

BACKGROUND: Multiple approaches to the paravertebral space have been described to produce analgesia after thoracic surgery. Ultrasound-guided regional anesthesia has the potential to improve efficacy and reduce complications via real-time visualization of the paravertebral space, surrounding structures, and the approaching needle. We compared a single- versus dual-injection technique for ultrasound-guided paravertebral blockade in a cadaver model, evaluating the spread of contrast dye and location of a catheter. METHODS: Thirty paravertebral injections and 20 catheter placements were performed on 10 fresh cadavers. The paravertebral space was identified using an ultrasound probe in the transverse plane using a linear transducer. An in-plane needle approach was used. Using analine contrast dye, a single 20-mL injection at T6-7 on one side and a dual-injection technique of 10 mL at T3-4 and T7-8 on the contralateral side were performed on each cadaver, followed by insertion of a catheter through the needle. The cadaver was then dissected to evaluate spread of contrast dye and catheter location. RESULTS: The paravertebral space was easily identified with ultrasound on each cadaver. Contrast dye was seen to surround somatic and sympathetic nerves in the paravertebral, intercostal, and epidural spaces. Contrast dye was present in 19 of 20 paravertebral spaces over 3 to 4 segments (range, 0-10) with no significant differences between single- and dual-injection techniques. Contrast dye spread more extensively across intercostal segments with 4.5 spaces (range, 2-10) covered with a single injection and 6 spaces (range, 2-8) covered with a dual-injection technique (P = 0.03). There was epidural spread of contrast in 40% of paravertebral injections in both single- and dual-injection techniques. Catheters were located in the paravertebral space (60%), prevertebral space (20%), and epidural space (5%). CONCLUSIONS: Transverse in-plane ultrasound-guided needle insertion into the thoracic paravertebral space is both feasible and reliable. However, paravertebral spread of contrast is highly variable with intercostal and epidural spread likely contributing significantly to the analgesic efficacy. A dual-injection technique at separate levels seems to cover more thoracic dermatomes because of greater segmental intercostal spread (rather than paravertebral spread) than a single-injection approach. Catheters are located in nonideal positions in 40% of cases using this in-plane technique.