Magnesium and Esophageal Pain After Peroral Endoscopic Myotomy of the Esophagus: A Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND: Postoperative esophageal pain occurs in 67% of patients after peroral endoscopic esophageal myotomy (POEM). Magnesium can act as a smooth muscle relaxant. This study investigated whether intraoperative magnesium can reduce postoperative esophageal pain in patients undergoing POEM. METHODS: In this double-blind, placebo-controlled trial, 92 patients were randomized to receive either magnesium sulfate as a 50 mg.kg-1 (total body weight) bolus followed by an infusion at 25 mg.kg-1.hr-1, or 0.9% saline. Intraoperative analgesia was standardized in all patients. The primary outcome was the score from a validated, modified Esophageal Symptoms Questionnaire (ESQ) in the postanesthesia care unit (PACU). Pain scores, opioid requirements, and questionnaire scores were collected through postoperative day 1. RESULTS: ESQ scores were significantly lower in the magnesium group in the PACU (median [25th-75th], 24 [18-31] vs 35 [28-42]; median difference [95% confidence interval, CI], 10 [6-13]; P < .0001) and on postoperative day 1 (16 [14-23] vs 30 [24-35]; P < .0001). Less opioids were needed in the magnesium group in the PACU (mean ± standard deviation [SD] [99% CI], 4.7 ± 10 [1-9] mg vs 29 ± 21 [21-37] mg; P < .0001) and on postoperative day 1 (1 ± 3.7 [0-2.5] mg vs 13 ± 23 [4-23] mg; P = .0009). Pain scores were lower in the magnesium group in the PACU (0 [0-3] vs 5 [5-7]; P < .0001) and on postoperative day 1 (0 [0-2] vs 4 [3-5]; P < .0001). CONCLUSIONS: Patients undergoing POEM randomized to receive intraoperative magnesium had sustained reductions in esophageal discomfort severity and opioid requirements 24 hours after surgery.

Clinical Outcomes of Erector Spinae Plane Block for Midline Sternotomy in Cardiac Surgery: A Systematic Review and Meta-Analysis.

OBJECTIVES: To evaluate the benefit of single-shot erector spinae plane block (ESPB) on pain at postoperative hours 4 and 12, duration of mechanical ventilation, hospital length of stay, intensive care unit (ICU) length of stay, cumulative postoperative opioid usage, and incidence of postoperative nausea and vomiting (PONV) after cardiac surgery via sternotomy DESIGN: A systematic review and meta-analysis of randomized controlled trials and prospective clinical trials. SETTING: Studies were identified through the search of PubMed and EMBASE on July 19, 2023. PARTICIPANTS: Adults and children undergoing cardiac surgery via sternotomy. INTERVENTIONS: Single-shot ESPB versus standard-of-care analgesia. MEASUREMENTS AND MAIN RESULTS: A systematic review and meta-analysis of 10 studies (N = 695 patients). The single-shot ESPB arm exhibited statistically significant reductions in pain score at postoperative hour 4 (standardized mean difference [SMD] -2.95, 95% CI -5.86 to -0.04, p = 0.0466), duration of mechanical ventilation (SMD -1.23, 95% CI -2.21 to -0.24, p = 0.0145), cumulative postoperative opioid usage (SMD -1.48, 95% CI -2.46 to -0.49, p = 0.0033), and PONV incidence (risk ratio 0.4358, 95% CI 0.2105-0.9021, p = 0.0252). The single-shot ESPB arm did not exhibit a statistically significant reduction in pain score at postoperative hour 12, length of hospital stay, and length of ICU stay. CONCLUSIONS: Single-shot ESPB improves near-term clinical outcomes in patients undergoing cardiac surgery via sternotomy. More randomized controlled trials are needed to validate these findings.

Characterization of Epidural Analgesia Interruption and Associated Outcomes After Esophagectomy.

INTRODUCTION: Interruption of thoracic epidural analgesia may impact the postoperative course following esophagectomy. This study investigates the incidence and causes of epidural interruption in esophagectomy patients along with associated postoperative outcomes. METHODS: This single-institution retrospective analysis examined patients undergoing esophagectomy who received a thoracic epidural catheter from 2016 to 2020. Patients were stratified according to whether epidural catheter infusion was interrupted or not postoperatively. Outcomes were compared between the two groups, and predictors of epidural interruption and postoperative complications were estimated using multivariable logistic regression. RESULTS: Of the 168 patients who received a thoracic epidural before esophagectomy, 60 (35.7%) required epidural interruption and 108 (64.3%) did not. Interruption commonly occurred on postoperative day 1 and was due to hypotension 80% of the time. Heart failure (10.0% versus 0.9%, P = 0.009), atrial fibrillation (20.0% versus 3.7%, P = 0.002), preoperative opioid use (30.0% versus 16.7%, P = 0.043), and higher American Society of Anesthesiology classification (88.4% versus 70.4%, P = 0.008) were more prevalent in the epidural interruption cohort. The female gender was associated with epidural interruption on multivariable logistic regression (adjusted odds ratio [AOR] 2.45, P = 0.039). Patients in the epidural interruption cohort had a higher incidence of delirium (30.5% versus 13.9%, P = 0.010), sepsis (13.6% versus 3.7%, P = 0.028), and severe anastomotic leak (18.3% versus 7.4%, P = 0.032). On adjusted analysis, heart disease (AOR 4.26, P = 0.027), BMI <18.5 (AOR 9.83, P = 0.031), and epidural interruption due to hypotension (AOR 3.51, P = 0.037) were associated with severe anastomotic leak. CONCLUSIONS: Early epidural interruption secondary to hypotension in esophagectomy patients may be a harbinger of postoperative complications such as sepsis and severe anastomotic leak. Patients requiring epidural interruption due to hypotension should have a low threshold for additional workup and early intervention.

Neuromodulation using a hybrid technique of combined perineural local anesthetic and nerve stimulation in six challenging clinical scenarios.

PURPOSE: Postamputation pain is challenging because of complex mechanisms involving a multitude of pain pathways and psychological factors. This patient population also tends to have extensive comorbidities with or without a background of chronic pain. Electrical neuromodulation such as peripheral nerve stimulation has gained traction in the realm of chronic pain. Recently, the off-label use of hybrid perineural nerve stimulation in combination with locoregional block via the stimulating nerve block catheter has been described in single-center case reports. CLINICAL FEATURES: Herein, we present a case series of six patients from two different Canadian hospitals using such a hybrid technique in three different clinical scenarios. These scenarios were (1) local anesthetic dose minimization in the presence of multiple nerve block catheters, (2) analgesia augmentation when local anesthetic alone is insufficient, and (3) provision of an analgesic adjunct as part of a multimodal regimen. A stimulating sciatic nerve block catheter was inserted under ultrasound and nerve stimulation guidance for these cases. Patients tended to experience pain on the subsequent postoperative days whereby the off-label use of nerve stimulation successfully reduced their pain score and stabilized or decreased their opioid consumption or minimized the need to increase the local anesthetic dose when doing so could have precipitated local anesthetic toxicity. CONCLUSION: Our case series supports the feasibility of using a combination of low-frequency perineural stimulation and local anesthetic infusion via a single perineural nerve block catheter to manage challenging postamputation pain.

RéSUMé: OBJECTIF: La douleur post-amputation est difficile à soulager en raison de mécanismes complexes impliquant une multitude de voies de la douleur et de facteurs psychologiques. Cette population de patients a également tendance à présenter de nombreuses comorbidités, avec ou sans antécédents de douleur chronique. Les techniques de neuromodulation électrique, telle que la stimulation nerveuse périphérique, sont de plus en plus populaires dans le domaine de la douleur chronique. Récemment, des présentations de cas monocentriques ont décrit l'utilisation hors indication d'une modalité hybride de stimulation nerveuse périneurale en combinaison avec un bloc locorégional via un cathéter de bloc nerveux stimulant. CARACTéRISTIQUES CLINIQUES: Nous présentons ici une série de cas de six patients de deux hôpitaux canadiens différents utilisant une telle technique hybride dans trois cas cliniques différents. Ces cas étaient (1) la minimisation de la dose d'anesthésique local en présence de plusieurs cathéters de blocs nerveux, (2) l'augmentation de l'analgésie lorsque l'anesthésique local seul était insuffisant, et (3) la fourniture d'un adjuvant analgésique dans le cadre d'un régime multimodal. Un cathéter stimulant pour l'administration d'un bloc du nerf sciatique a été inséré sous échoguidage et guide de stimulation nerveuse pour ces cas. Les patients ont eu tendance à ressentir de la douleur les jours postopératoires suivants, et l'utilisation hors indication de la stimulation nerveuse a alors réussi à réduire leur score de douleur, à stabiliser ou diminuer leur consommation d'opioïdes, ou à réduire la nécessité d'augmenter la dose d'anesthésique local alors que cela aurait pu précipiter une toxicité anesthésique locale. CONCLUSION: Notre série de cas soutient la faisabilité de l'utilisation d'une technique combinée de stimulation périnerveuse à basse fréquence et de perfusion d'anesthésique local via un seul cathéter de bloc nerveux périneural pour prendre en charge la douleur post-amputation.

Continuous interscalene versus phrenic nerve-sparing high-thoracic erector spinae plane block for total shoulder arthroplasty: a randomized controlled trial.

PURPOSE: The high-thoracic erector spinae plane block (HT-ESPB) has been reported as an effective analgesic modality for the shoulder region without phrenic nerve palsy. The goal of this study was to compare the HT-ESPB as a phrenic nerve-sparing alternative to an interscalene block for total shoulder arthroplasty. METHODS: Thirty patients undergoing total shoulder arthroplasty at Stanford Health Care (Palo Alto, CA, USA) were enrolled in a double-blind randomized controlled trial. We randomized 28 patients to receive either an interscalene or HT-ESPB perineural catheter preoperatively; 26 patients were included in the final analysis. The study was powered for the primary outcome of incidence of hemidiaphragmatic paralysis in the postanesthesia care unit (PACU). Other outcome measures included incentive spirometry volume, brachial plexus motor and sensory exams, adverse events, pain scores, and opioid consumption. RESULTS: The incidence of hemidiaphragmatic paralysis in the HT-ESPB catheter group was significantly lower than in the interscalene catheter group (0/12, 0% vs 14/14, 100%; P < 0.001). No statistically significant differences were found in pain scores and opioid consumption (in oral morphine equivalents) between the interscalene and HT-ESPB groups through postoperative day (POD) 2. Nevertheless, the mean (standard deviation) point estimates for opioid consumption for the HT-ESPB group were higher than for the interscalene group in the PACU (HT-ESPB: 24.8 [26.7] mg; interscalene: 10.7 [21.7] mg) and for POD 0 (HT-ESPB: 20.5 [25.0] mg; interscalene: 6.7 [12.0] mg). In addition, cumulative postoperative opioid consumption was significantly higher at POD 0 (PACU through POD 0) in the HT-ESPB group (45.3 [39.9] mg) than in the interscalene group (16.6 [21.9] mg; P = 0.04). CONCLUSIONS: This study suggests that continuous HT-ESPB can be a phrenic nerve-sparing alternative to continuous interscalene brachial plexus blockade, although the latter provided superior opioid-sparing in the immediate postoperative period. This was a small sample size study, and further investigations powered to detect differences in analgesic and quality of recovery score endpoints are needed. STUDY REGISTRATION: www. CLINICALTRIALS: gov (NCT03807505); registered 17 January 2019.

RéSUMé: OBJECTIF: Le bloc des muscles érecteurs du rachis du haut thorax (BMER-HT) a été rapporté comme une modalité analgésique efficace pour la région de l'épaule et ce, sans paralysie du nerf phrénique. L'objectif de cette étude était de comparer ce bloc en tant qu'alternative épargnant le nerf phrénique à un bloc interscalénique pour l'arthroplastie totale de l'épaule. MéTHODE: Trente patients bénéficiant d'une arthroplastie totale de l'épaule au centre de soins Stanford Health Care (Palo Alto, CA, États-Unis) ont été recrutés dans une étude randomisée contrôlée à double insu. Nous avons randomisé 28 patients à recevoir un cathéter périneural interscalénique ou un BMER-HT en préopératoire; 26 patients ont été inclus dans l'analyse finale. Le calcul de puissance de l'étude a été effectué pour répondre au critère d'évaluation principal, qui était l'incidence de paralysie hémidiaphragmatique en salle de réveil. Les autres issues mesurées comprenaient les volumes de spirométrie, les examens moteurs et sensoriels du plexus brachial, les événements indésirables, les scores de douleur et la consommation d'opioïdes. RéSULTATS: L'incidence de paralysie hémidiaphragmatique dans le groupe cathéter BMER-HT était significativement plus faible que dans le groupe cathéter interscalénique (0/12, 0 % vs 14/14, 100 %; P < 0,001). Aucune différence statistiquement significative n'a été observée dans les scores de douleur et la consommation d'opioïdes (en équivalents morphine par voie orale) entre les groupes interscalénique et BMER-HT jusqu'au jour postopératoire (JPO) 2. Néanmoins, en salle de réveil, les estimations ponctuelles moyennes (écart type) de la consommation d'opioïdes pour le groupe BMER-HT étaient plus élevées que pour le groupe interscalénique (BMER-HT : 24,8 [26,7] mg; interscalénique : 10,7 [21,7] mg), ainsi qu'au JPO 0 (BMER-HT : 20,5 [25,0] mg; interscalénique: 6,7 [12,0] mg). De plus, la consommation cumulative d'opioïdes postopératoires était significativement plus élevée au JPO 0 (salle de réveil jusqu'au JPO 0) dans le groupe BMER-HT (45,3 [39,9] mg) que dans le groupe interscalénique (16,6 [21,9] mg; P = 0,04). CONCLUSION: Cette étude suggère que le BMER-HT continu peut être une alternative au bloc interscalénique continu du plexus brachial pour épargner le nerf phrénique, bien que le bloc interscalénique ait fourni une épargne d'opioïdes supérieure en période postopératoire immédiate. Il s'agissait d'une étude de petite taille d'échantillon, et d'autres études visant à détecter les différences dans les scores des critères d'évaluation en matière d'analgésie et de qualité de la récupération sont nécessaires. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT03807505); enregistrée le 17 janvier 2019.

Preemptive and Preventive Pain Psychoeducation and Its Potential Application as a Multimodal Perioperative Pain Control Option: A Systematic Review.

The common treatment for postoperative pain is prescription opioids. Yet, these drugs have limited effect in preventing chronic pain from surgical intervention and have in part contributed to the opioid epidemic. Recently, preemptive analgesia and multimodal analgesia have been proposed with widely gained acceptance in addressing the pain issues. However, both analgesic approaches have been focused on pharmacological means while completely neglecting the psychological aspect. To address this epidemic, we have conducted a systematic review of preoperative educational methods to explore its application as both a preemptive and a preventive psychological approach to decrease postsurgical pain and improve outcome. Preemptive psychoeducation occurs before surgery and would include information about regional or neuraxial analgesia, while preventive psychoeducation occurs throughout the perioperative period. The content and presentation of preemptive psychoeducation can help patients form accurate expectations and address their concerns of surgical outcome, leading to a significant decrease in patients' anxiety levels. By addressing the psychological needs of patients through preoperative education, one can decrease postoperative recovery time and postsurgical acute pain. Reduced postsurgical acute pain results in fewer opioid prescriptions, which theoretically lowers the patient's risk of developing chronic postsurgical pain (CPSP), and potentially offers a novel concept using preemptive pain psychoeducation as a part of multimodal pain management solution to the opioid epidemic.

Programmed Intermittent Bolus Regimen for Erector Spinae Plane Blocks in Children: A Retrospective Review of a Single-Institution Experience.

With few published reports on erector spinae plane block use in children, limited guidance on perioperative local anesthetic dosing exists. We present a series of 22 patients who received erector spinae plane catheters with programmed intermittent bolus for various surgeries. Median loading dose of 0.4 mL/kg (interquartile range [IQR], 0.1 mL/kg) ropivacaine 0.5%, intraoperative bolus of 0.3 mL/kg/h (IQR, 0.1 mL/kg) ropivacaine 0.2%, and a postoperative programmed intermittent bolus regimen of maximum 0.6 mg/kg/h resulted in highest pain scores on postoperative day 1 with a median score of 1.7 of 10 (IQR, 1.8) and highest morphine equivalents consumed on postoperative day 2 with a median score of 0.16 mg/kg up to 120 hours after surgery.

Speeding the Detection of Vessel Cannulation: An In-Vitro Stimulation Study.

BACKGROUND: Some practitioners "prime" small IV angiocatheter needles with 0.9% sodium chloride-claiming this modification speeds visual detection of blood in the angiocatheter flash chamber on vessel cannulation. METHODS: We compared the time required for human blood to travel the length of saline-primed and saline-unprimed 24- and 22-gauge angiocatheter needles (Introcan Safety IV Catheter; B. Braun, Bethlehem, PA). A syringe pump (Medfusion 4000, Cary, NC) advanced each angiocatheter needle through the silicone membrane of an IV tubing "t-piece" (Microbore Extension Set, 5 Inch; Hospira, Lake Forest, IL) filled with freshly donated human blood. When the angiocatheter needle contacted the blood, an electrical circuit was completed, illuminating a light-emitting diode. We determined the time from light-emitting diode illumination to visual detection of blood in the flash chamber by video review. We tested 105 saline-primed angiocatheters and 105 unprimed angiocatheters in the 24- and 22-gauge angiocatheter sizes (420 catheters total). We analyzed the median time to visualize the flash using the nonparametric Wilcoxon rank sum test in R (http://www.R-project.org/). The Stanford University Administrative Panel on Human Subjects in Medical Research determined that this project did not meet the definition of human subjects research and did not require institutional review board oversight. RESULTS: In the 24-gauge angiocatheter group, the median (and interquartile range) time for blood to travel the length of the unprimed angiocatheter needle was 1.14 (0.61-1.47) seconds compared with 0.76 (0.41-1.20) seconds in the saline-primed group (P = 0.006). In the 22-gauge catheter group, the median (interquartile range) time for blood to travel the length of the unprimed angiocatheter needle was 1.80 (1.23-2.95) seconds compared with 1.46 (1.03-2.54) seconds in the saline-primed group (P = .046). CONCLUSIONS: These results support the notion that priming small angiocatheter needles, in particular 24-gauge catheters, with 0.9% sodium chloride may provide earlier detection of vessel cannulation than with the unprimed angiocatheter.

Systemic Absorption of Lidocaine from Continuous Erector Spinae Plane Catheters After Congenital Cardiac Surgery: A Retrospective Study.

OBJECTIVES: To examine postoperative serum lidocaine levels in patients with intermittent lidocaine bolus erector spinae plane block (ESPB) catheters after cardiac surgery with or without cardiopulmonary bypass (CPB). DESIGN: A retrospective study. SETTING: Single-center pediatric quaternary teaching hospital. PARTICIPANTS: Patients who received ESPB catheters after congenital cardiac surgery from April 2018 to March 2019. INTERVENTIONS: Postoperative serum lidocaine levels were extracted from the record. MEASUREMENTS AND MAIN RESULTS: Twenty-seven of 40 patients were included in the final analyses (19 with CPB and 8 with no CPB, age 1-47 years, undergoing congenital heart repair). Patients who received ropivacaine or were missing data were excluded. The initial intraoperative bolus of lidocaine ranged from 0- to- 3.72 mg/kg, and the range of postoperative intermittent lidocaine boluses ranged from 0.35- to- 0.83 mg/kg, which were administered every hour. Serum lidocaine levels were measured by the hospital laboratory and ranged from <0.05- to- 3.0 µg/mL in the CPB group and from <0.05- to- 3.2 µg/mL in the no- CPB group. CPB was not associated with differences in lidocaine levels when controlling for time (P = 0.529). Lidocaine concentrations ranged from 0.50- to- 1.68 µg/mL in the CPB group and 0.86- to- 2.07 µg/mL in the no- CPB group. There was a normally distributed overall mean peak level of 1.818 ± standard deviation of 0.624 µg/mL, with 95% confidence interval of 0.57- to- 3.06 µg/mL. No patients had clinical signs of toxicity. CONCLUSION: Postoperative serum lidocaine concentrations did not appreciably differ due to CPB. Serum lidocaine concentrations did not reach near- toxic doses despite the presence of additional lidocaine in the cardioplegia. The results suggested that lidocaine for ESPBs after cardiac surgery is below systemic toxic range at the doses described.

Practice advisory on the bleeding risks for peripheral nerve and interfascial plane blockade: evidence review and expert consensus.

The risk of bleeding complications during regional anesthesia procedures is a significant patient safety consideration. Nevertheless, existing literature provides limited guidance on the stratification of bleeding risk for peripheral nerve and newly described interfascial plane blocks. Our objective was to produce an evidence-based consensus advisory that classifies bleeding risks in patients undergoing regional peripheral nerve and interfascial plane block procedures. This advisory is intended to facilitate clinical decision-making in conjunction with national or local guidelines and to guide consideration for appropriate alterations to anticoagulation regimens before specific regional anesthesia procedures. In pursuit of this goal, the Regional Anesthesia and Acute Pain Section of the Canadian Anesthesiologists Society (CAS) assembled a panel of seven Canadian experts to classify the risk of bleeding complications associated with regional peripheral nerve and interfascial plane blocks. At the 75th annual meeting of the CAS in June 2018, the panel's expert opinion was finalized and the published literature was quantified within an organized framework. All common peripheral nerve and interfascial plane blocks were categorized into "low risk", "intermediate risk", and "high risk" based on the literature evidence, bleeding risk scores, and consensus opinion (in that order of priority). Clinical data is often limited, so readers of this consensus report should be reminded that these recommendations are mostly based on expert consensus. Hence, this advisory should not to be defined as a standard of care but rather serve as a resource for clinicians assessing the risk and benefits of regional anesthesia in management of their patients.

Regional anesthesia for cardiac surgery.

PURPOSE OF REVIEW: Anesthesia for cardiac surgery has traditionally utilized high-dose opioids to blunt the sympathetic response to surgery. However, recent data suggest that opioids prolong postoperative intubation, leading to increased morbidity. Given the increased risk of opioid dependency after in-hospital exposure to opioids, coupled with an increase in morbidity, regional techniques offer an adjunct for perioperative analgesia. The aim of this review is to describe conventional and emerging regional techniques for cardiac surgery. RECENT FINDINGS: Well-studied techniques such as thoracic epidurals and paravertebral blocks are relatively low risk despite lack of widespread adoption. Benefits include reduced opioid exposure after paravertebral blocks and reduced risk of perioperative myocardial infarction after epidurals. To further lower the risk of epidural hematoma and pneumothorax, new regional techniques have been studied, including parasternal, pectoral, and erector spinae plane blocks. Because these are superficial compared with paravertebral and epidural blocks, they may have even lower risks of hematoma formation, whereas patients are anticoagulated on cardiopulmonary bypass. Efficacy data have been promising, although large and generalizable studies are lacking. SUMMARY: New regional techniques for cardiac surgery may be potent perioperative analgesic adjuncts, but well-designed studies are needed to quantify the effectiveness and safety of these blocks.

Ultrasound-guided lateral-medial transmuscular quadratus lumborum block for analgesia following anterior iliac crest bone graft harvesting: a clinical and anatomical study.

BACKGROUND: The anterior iliac crest (AIC) is one of the most common sites for harvesting autologous bone, but the associated postoperative pain can result in significant morbidity. Recently, the transmuscular quadratus lumborum block (TQL) has been described to anesthetize the thoraco-lumbar nerves. This study utilizes a combination of cadaveric models and clinical case studies to evaluate the dermatomal coverage and analgesic utility of TQL for AIC bone graft donor site analgesia. METHODS: Ten ultrasound-guided TQL injections were performed in five cadaver specimens using a lateral-to-medial transmuscular approach. Twenty mL of 0.5% methylcellulose was injected on each side after ultrasound confirmation of the needle tip ventral to the quadratus lumborum muscle (QLM). Cranio-caudal and medial-lateral extent of the dye spread in relation to musculoskeletal anatomy and direct staining of the thoraco-lumbar nerves were recorded. Following the anatomical findings, continuous catheter TQL blocks were performed in four patients undergoing ankle surgery with autologous AIC bone graft. The dermatomal anesthesia and postoperative analgesic consumption were recorded. RESULTS: In the anatomical component of the study, 9/10 specimens showed a lateral spread anterior to the transversalis fascia and medially between the QLM and psoas major muscle. Direct staining of the branches of the T12, L1, and L2 nerves was noted ventral to the QLM, while variable staining of the T9-T11 nerves was seen laterally in the transversus abdominis plane and the transversalis fascia. The vertical spread of injectate anterior to the QLM was T12 to the iliac crest (n = 5/10) and L1 to the iliac crest (n = 4/10). In the four patients who received TQL, the T9-L2 dermatomal anesthesia correlated with the injectate spread seen in the cadavers and provided effective analgesia at the bone graft donor site. CONCLUSION: Ultrasound-guided TQL injections consistently cover the thoraco-lumbar innervation relevant to the AIC graft donor site. The injectate spread seen in anatomical dissections correlated with the dermatomal anesthesia clinically. The TQL has the potential to provide reliable analgesia for patients undergoing AIC bone graft harvesting.

Factors Associated With Risk of Neurologic Complications After Peripheral Nerve Blocks: A Systematic Review.

The onset of neurologic complications after regional anesthesia is a complex process and may result from an interaction of host, agent, and environmental risk factors. The purpose of this systematic review was examine the qualitative evidence relating to various risk factors implicated in neurologic dysfunction after peripheral nerve block (PNB). The MEDLINE, OVID, and EMBASE databases were primary sources for literature. Cochrane, LILACS, DARE, IndMed, ERIC, NHS, and HTA via Centre for Reviews and Dissemination (CRD; York University) databases were searched for additional unique results. Randomized controlled studies, case-control studies, cohort studies, retrospective reviews, and case reports/case series reporting neurologic outcomes after PNB were included. Relevant, good-quality systematic reviews were also eligible. Human and animal studies evaluating factors important for neurologic outcomes were assessed separately. Information on study design, outcomes, and quality was extracted and reviewed independently by the 2 review authors. An overall rating of the quality of evidence was assigned using GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. Relevant full-text articles were separated based on type (prospective, retrospective, and nonhuman studies). Strengths of association were defined as high, moderate, inconclusive, or inadequate based on study quality and direction of association. The evidence from 77 human studies was reviewed to assess various host, agent, and environmental factors that have been implicated as possible risks. Most of the available evidence regarding the injurious effects of the 3 cardinal agents of mechanical insult, pressure, and neurotoxicity was extracted from animal studies (42 studies). Among the risk factors investigated in humans, block type had a strong association with neurologic outcome. Intraneural injection, which seems to occur commonly with PNBs, showed an inconsistent direction of association. Measures meant to increase precision and ostensibly reduce the occurrence of complications such as currently available guidance techniques showed little effect on the incidence of neurologic complications. Recovery from neurologic injury appears to be worse in patients with pre-existing risk factors. Categorization and definition of neurologic complication varied among studies, making synthesis of evidence difficult. Also, a significant portion of the evidence surrounding neurologic injury associated with PNB comes from animal or laboratory studies, the results of which are difficult to translate to clinical scenarios. Of the human studies, few had an a priori design to test associations between a specific risk factor exposure and resultant neurologic sequelae. A few risk factor associations were identified in human studies, but overall quality of evidence was low. Much of the evidence for risk factors comes from animal models and case reports. The final neurologic outcome seems to represent the complex interaction of the host, agent, and the environment.

The effect of an increased pulse width on the pattern of motor response (unilateral versus bilateral) during the Tsui test in labouring parturients: a randomized crossover trial.

BACKGROUND AND OBJECTIVES: The typical response to the Tsui test performed via an epidural catheter placed in the lumbar area is the unilateral motor response of the lower limbs. Studies show that longer pulse widths can stimulate peripheral nerves at a lower threshold current from a farther distance. Therefore, we designed a study to test the hypothesis that epidural catheter stimulation with a 1.0-msec pulse width would increase the incidence of bilateral motor response in parturients when compared with stimulation with a 0.1-msec pulse width. METHODS: Parturients requesting epidural analgesia were recruited into this randomized crossover study. The Tsui test was performed at both pulse widths before and five minutes after an epidural test dose of 2% lidocaine 3 mL. The primary outcome was the motor response pattern (either unilateral or bilateral) to the epidural catheter stimulation at baseline. RESULTS: Twenty women were recruited for the study, which was stopped early due to futility. The rates of unilateral motor response in the 0.1-msec (18/20) and the 1-msec (18/20) group were both 90% (rate difference, 0%; 95% confidence interval [CI], -0.3 to 0.3; P = 1.0). The mean (SD) current required to elicit a motor response at baseline was 4.2 (2.6) mA in the 0.1-msec group and 1.7 (1.1) mA in the 1-msec group (mean difference, 2.5; 95% CI, 1.2 to 2.3; P < 0.001). CONCLUSIONS: The motor response pattern following the stimulation of a lumbar epidural catheter with pulse widths of 0.1 msec or 1 msec is similar and typically unilateral. The threshold current is lower with the 1-msec pulse width stimulus. TRIAL REGISTRATION: www.clinicaltrials.gov, NCT02762149. Registered 2 May 2016.