A Dose-Ranging Study of 0.5% Bupivacaine or Ropivacaine on the Success and Duration of the Ultrasound-Guided, Nerve-Stimulator–Assisted Sciatic Nerve Block: A Double-Blind, Randomized Clinical Trial

A phase 3 active-controlled trial of liposomal bupivacaine via sciatic nerve block in the popliteal fossa after bunionectomy

STUDY OBJECTIVE

To investigate the efficacy, safety, pharmacodynamics, and pharmacokinetics of liposomal bupivacaine (LB) administered via ultrasound-guided sciatic nerve block in the popliteal fossa in participants undergoing bunionectomy.

DESIGN

Two-part, randomized, double-blind, active-controlled trial (NCT05157841).

SETTING

Operating room, postanesthesia care unit, and health care facility (6 sites).

PATIENTS

Adults with American Society of Anesthesiologists physical status classification ≤3 and body mass index ≥18 to <40 kg/m2 undergoing elective distal metaphyseal osteotomy.

INTERVENTIONS

Part A participants were randomized 1:1:1 to LB 266 mg, LB 133 mg, or bupivacaine hydrochloride 50 mg (BUPI). Part B participants were randomized 1:1 to LB (at the dose established by part A) or BUPI.

MEASUREMENTS

The primary endpoint was area under the curve (AUC) of numerical rating scale (NRS) pain intensity scores 0-96 h after surgery. Secondary endpoints included total postsurgical opioid consumption, opioid-free status 0-96 h after surgery, and pharmacokinetic endpoints.

MAIN RESULTS

Part A enrolled 22 participants per group. In part B, additional participants were randomized to LB 133 mg (n = 59) and BUPI (n = 60) (185 total). LB 133 mg had significant reductions versus BUPI in the AUC of NRS pain intensity score (least squares mean [LSM], 207.4 vs 371.4; P < 0.00001) and total opioid consumption 0-96 h after surgery (LSM, 17.7 [95% confidence interval (CI), 13.7, 22.8] morphine milligram equivalents [MMEs] vs 45.3 [95% CI, 35.1, 58.5] MMEs; P < 0.00001) and an increased proportion of opioid-free participants (24.4% vs 6%; odds ratio, 5.04 [95% CI, 2.01, 12.62]; P = 0.0003) in parts A + B. Adverse events were similar across groups.

CONCLUSIONS

LB 133 mg administered via sciatic nerve block in the popliteal fossa after bunionectomy demonstrated superior and long-lasting postsurgical pain control versus BUPI. The clinical relevance of these findings is supported by concurrent reductions in pain and opioid consumption over 4 days after surgery and a significantly greater percentage of participants remaining opioid-free.

Minimum effective concentration of ropivacaine for ultrasound-guided transmuscular quadratus lumborum block in total hip arthroplasty: a randomized clinical trial

OBJECTIVE

This trial aimed to identify the Minimum Effective Concentration (MEC90, defined as the concentration which can provide successful block in 90% of patients) of 30 mL ropivacaine for single-shot ultrasound-guided transmuscular Quadratus Lumborum Block (QLB) in patients undergoing Total Hip Arthroplasty (THA).

METHODS

A double-blind, randomized dose-finding study using the biased coin design up-and-down sequential method, where the concentration of local anesthetic administered to each patient depended on the response from the previous one. Block success was defined as a Numeric Rating Scale (NRS) score during motion ≤ 3 at 6 hours after arrival in the ward. If the block was successful, the next subject received either a 0.025% smaller dose (probability of 0.11) or the same dose (probability of 0.89); otherwise, the next subject received a 0.025% higher ropivacaine concentration. MEC90, MEC95 and MEC99 were estimated by isotonic regression, and the corresponding 95% Confidence Intervals (95% CIs) were calculated by the bootstrapping method.

RESULTS

Based on the analysis of 52 patients, MEC90, MEC95, and MEC99 of ropivacaine for QLB were estimated to be 0.352% (95% CI 0.334-0.372%), 0.363% (95% CI 0.351-0.383%), and 0.373% (95% CI 0.363-0.386%). The concentration of ropivacaine at 0.352% in a volume of 30 ml can provide a successful block in 90% of patients.

CONCLUSIONS

For ultrasound-guided transmuscular QLB in patients undergoing THA, 0.352% ropivacaine in a volume of 30 ml can provide a successful block in 90% of patients. Further dose-finding studies and large sample size are required to verify the concentration.

Ultrasound-guided sciatic nerve block in Wistar rat cadavers: Relevant anatomy and injection distribution

OBJECTIVE

To investigate the feasibility of an ultrasound-guided sciatic nerve block by describing the sonoanatomy and comparing the distribution of two volumes of bupivacaine dye solution for nerve staining.

STUDY DESIGN

Randomized, experimental, assessor-blinded cadaveric study.

ANIMALS

A total of 40 adult female Wistar rat cadavers.

METHODS

After studying the sonoanatomy of the sciatic nerve and adjacent structures using a high-resolution linear transducer (19-5 MHz), rat cadavers were randomly divided into two groups that were administered either 0.1 mL (group 0.1) or 0.2 mL (group 0.2) of bupivacaine dye solution per nerve, delivered via an in-plane technique. The extent of nerve staining was subsequently evaluated following dissection. Statistical analysis consisted of assessing data distribution using the Shapiro-Wilk test, followed by paired t-tests for continuous data, Mann-Whitney U test and McNemar's test for categorical data. Statistical significance was defined as p < 0.05.

RESULTS

The sciatic nerve was identified bilaterally as a double ellipsoid-shaped image, surrounded by a hyperechoic fascia separating the biceps femoris from the adductor muscle. The hypoechoic structure formed by the bupivacaine dye solution around the nerve was effectively visualized using ultrasound imaging. Sciatic nerve staining was successfully achieved in all pelvic limbs, with dye spread of 4.82 ± 1.55 mm and 5.47 ± 2.18 mm in groups 0.1 and 0.2, respectively (p = 0.128).

CONCLUSIONS AND CLINICAL RELEVANCE

This study achieved a detailed understanding of the sonoanatomy of the sciatic nerve and its adjacent structures, highlighting the feasibility of the ultrasound-guided technique for injection in Wistar rats. Furthermore, the results show a comparable distribution of dye solution in both groups. Use of the ultrasound-guided sciatic nerve block technique in rats not only exhibits substantial potential for regional anesthesia but also opens avenues for translational studies.

Analgesic efficacy of anterior iliopsoas muscle space block combined with local infiltration analgesia after total hip arthroplasty: A prospective, double-blind, placebo-controlled study

BACKGROUND

The present study aimed to evaluate the efficacy of ultrasound-guided anterior iliopsoas muscle space block (AIMSB) combined with local infiltration analgesia (LIA) for pain management and recovery in patients who have undergone total hip arthroplasty (THA) via a posterolateral approach.

METHODS

In this prospective, double-blind, placebo-controlled study, 80 patients undergoing primary THA under general anesthesia were included in the final analysis between March 22, 2022, and June 1, 2022. All patients were randomly assigned to receive AIMSB combined with LIA (AIMSB group, n = 40) or sham AIMSB and LIA (Sham group, n = 40). The primary outcome was cumulative morphine consumption (mg) within 24 h after surgery. Secondary outcomes were pain scores on a visual analog scale (VAS) at rest or during motion after surgery, time to first rescue analgesia, cumulative morphine consumption during hospitalization, intraoperative consumption of opioids, postoperative recovery, and postoperative adverse effects.

RESULTS

Patients in the AIMSB group consumed significantly less morphine than the Sham group within the first 24 h and throughout hospitalization, as well as smaller amounts of intraoperative opioids. Also, significantly lower pain scores were recorded at rest or during motion within 24 h after surgery in AIMSB patients. Patients in the AIMSB group recovered more quickly than Sham patients. No significant difference was observed in quadriceps strength and postoperative complications between the two groups.

CONCLUSIONS

Compared to treatment with LIA alone, ultrasound-guided AIMSB combined with LIA can provide better postoperative pain relief, decrease opioid consumption, promote motor sparing, and enhance the recovery of THA patients.

Emulsion-induced polymersomes taming tetrodotoxin for prolonged duration local anesthesia

Injectable local anesthetics that can provide a continuous nerve block approximating the duration of a pain state would be a life-changing solution for patients experiencing post-operative pain or chronic pain. Tetrodotoxin (TTX) is a site 1 sodium channel blocker that is extremely potent compared to clinically used local anesthetics. Challengingly, TTX doses are limited by its associated systemic toxicity, thus shortening the achievable duration of nerve blocks. Here, we explore emulsion-induced polymersomes (EIP) as a drug delivery system to safely use TTX for local anesthesia. By emulsifying hyperbranched polyglycerol-poly (propylene glycol)-hyperbranched polyglycerol (HPG-PPG-HPG) in TTX aqueous solution, HPG-PPG-HPG self-assembled into micrometer-sized polymersomes within seconds. The formed polymersomes have microscopically visible internal aqueous pockets that encapsulate TTX with an encapsulation efficiency of up to 94%. Moreover, the polymersomes are structurally stable, enabling sustained TTX release. In vivo, the freshly prepared EIP/TTX formulation can be directly injected and increased the tolerated dose of TTX in Sprague-Dawley rats to 11.5 μg without causing any TTX-related systemic toxicity. In the presence of the chemical penetration enhancer (CPE) sodium octyl sulfate (SOS), a single perineural injection of EIP/TTX/SOS formulation produced a reliable sciatic nerve block for 22 days with minimal local toxicity.

Efficacy of Ultrasound-Guided Pericapsular Nerve Group (PENG) Block Combined With Local Infiltration Analgesia on Postoperative Pain After Total Hip Arthroplasty: A Prospective, Double-Blind, Randomized Controlled Trial

BACKGROUND

This study examined whether pericapsular nerve group (PENG) block combined with local infiltration analgesia (LIA) could improve pain management and functional recovery after total hip arthroplasty.

METHODS

All patients were randomly assigned to receive PENG block combined with LIA (PENG group) or sham PENG block and LIA (Sham group). The primary outcome was cumulative morphine consumption within 24 hours after surgery. Secondary outcomes were pain scores on a visual analog scale (VAS); time to first rescue analgesia; cumulative morphine consumption during hospitalization; intraoperative consumption of opioids; postoperative recovery; and postoperative complications.

RESULTS

PENG patients consumed significantly less morphine within the first 24 hours and throughout hospitalization and smaller amounts of intraoperative opioids. There were significantly lower pain scores at rest and during motion within 24 hours in PENG patients. PENG patients took significantly longer until the first rescue analgesia and showed significantly better postoperative rehabilitation. However, the absolute change in morphine consumption and VAS scores did not exceed the reported minimal clinically important differences (morphine consumption: 10 mg; VAS scores: 1.5 at rest and 1.8 during movement). The two groups showed no difference in quadriceps muscle strength and postoperative complications.

CONCLUSION

PENG block combined with LIA could improve postoperative pain relief, reduce opioid use, and enhance recovery in total hip arthroplasty patients, without weakening the quadriceps muscle strength. This work justifies further trials to examine the safety and efficacy of this block and to explore maximal effective volume of local anesthetic for motor-sparing PENG block.

Effect of suprainguinal fascia iliaca compartment block on postoperative opioid consumption and functional recovery in posterolateral-approached total hip arthroplasty: a single-blind randomized controlled trial

INTRODUCTION

Posterolateral-approached total hip arthroplasty (PLTHA) is followed by moderate to severe postoperative pain. Suprainguinal fascia iliaca compartment block (SFICB) has been proposed as a promising analgesia technique.

METHODS

Data from 86 patients scheduled for PLTHA with spinal anesthesia were analyzed in this prospective randomized controlled trial. Patients were randomly divided into two groups of 43 patients each. As opposed to the control group (group C), ropivacaine group (group R) received additional SFICB using 40 mL of 0.375% ropivacaine. As primary endpoint, blind observers noted total morphine consumption at postoperative 48 hours. Secondary endpoints were pain at rest and mobilization on 0-10 Numeric Rating Scale (rest and dynamic NRS) at fixed time points (1 hour and 6 hours after surgery, and at day 1 and day 2 at 8:00, 13:00 and 18:00 hours), walking performance at day 1 and day 2; postoperative complications including morphine-related side effects or orthostatic intolerance symptoms such as dizziness, nausea, blurred vision or vasovagal syncope.

RESULTS

A 48-hour morphine consumption (mg; median (IQR)) was significantly lower in group R than in group C (11 (8.5-15.5)) vs 26 (21-33.5), p<0001), as well as incidence of morphine-related side effects such as nausea at day 1 (p=0.04) and day 2 (p<0.01). Rest and dynamic NRS were globally significantly lower in group R than in group C (p<0.01). Group R showed less orthostatic intolerance at day 1 (p<0.001) and day 2 (p<0.01) and better functional walking performance at day 1 (<0.001) and day 2 (<0.001).

DISCUSSION

In PLTHA, SFICB provides opioid sparing, improved postoperative pain control, and enhanced functional recovery.

TRIAL REGISTRATION NUMBER

NCT04574479.

Dexmedetomidine as an adjunct to peripheral nerve blocks in pediatric patients

BACKGROUND

Combining local anesthetics with dexmedetomidine (DEX) for nerve blocks has been tested and confirmed as an alternative technique to strengthen analgesia in adults, but the evidence supported this proposal in pediatrics was not convincing enough. Thus, we intend to conduct a meta-analysis to make an appraisal of the effects of DEX as a local anesthetic adjuvant on peripheral nerve blocks in children.

METHODS

The analysis has been registered on https://www.crd.york.ac.uk/prospero/ with the registration number CRD42021254029 on June 10th, 2021. PubMed, Ovid MEDLINE, Embase and Cochrane central register were searched for the randomized controlled trials (RCTs) that are relevant to child/pain/DEX or block up to April 30, 2021.

RESULTS

Eight RCTs were included for data analysis. The pooled results showed a significantly reduced number of patients who required postoperative analgesics within DEX groups [odds ratio = 0.1, 95% confidence interval (CI) 0.03-0.32, P < 0.001]. And DEX significantly prolonged the duration of analgesia of local anesthetics in the meantime [standardized mean difference (SMD) = 4.93, 95% CI 3.02-6.83, P < 0.001]. Nevertheless, adding DEX as an adjunct to local anesthetics would significantly decrease heart rate (SMD = - 0.95, 95% CI - 1.45 to - 0.45, P < 0.001) and increase sedation score (SMD = 1.6, 95% CI 0.53-2.66, P = 0.003) simultaneously.

CONCLUSIONS

Adding DEX as an adjunct to peripheral nerve blocks can prolong analgesia until postoperative 8 hours in pediatric patients. However, the benefits should be weighed against the increasing risk of bradycardia and sedation in critical children.

The impact of ultrasound-guided transmuscular quadratus lumborum block combined with local infiltration analgesia for arthroplasty on postoperative pain relief

STUDY OBJECTIVE

This study aimed to evaluate the efficacy of ultrasound-guided transmuscular quadratus lumborum block (QLB) combined with local infiltration analgesia (LIA) for pain management and recovery in patients who have undergone total hip arthroplasty (THA) via a posterolateral approach.

DESIGN

This was a prospective, randomized controlled trial.

SETTING

We collected data in the preoperative area, operating room, and bed ward.

PATIENTS

A total of 80 patients with American Society of Anesthesiology functional status scores of II-III were included and assigned to two groups, and all 80 patients were included in the final analysis.

INTERVENTIONS

All included patients were randomly assigned to the nerve block (group N) or the control group (group C). Patients in the group N received transmuscular QLB combined with LIA, while patients in the group C received only LIA.

MEASUREMENTS

The primary outcome was postoperative pain during the first active motion: it was measured at six hours after surgery and assessed using a visual analog scale (VAS). Secondary outcomes were the resting VAS scores in the post-anesthesia care unit (PACU) and at 2, 6, 12, 24, 48, and 72 h after surgery; VAS scores during motion at 12, 24, 48, and 72 h after surgery; intraoperative consumption of opioids; postoperative consumption of morphine hydrochloride; frequency of sleep interruption due to pain on the night of surgery; time until the first "walk out of the bed" after surgery; muscle strength of the quadriceps femoris; and postoperative adverse effects.

MAIN RESULTS

Compared to the group C, patients in the group N had significantly lower VAS scores during motion at 6, 12, and 24 h after surgery, as well as lower resting VAS scores in the PACU and at 2, 6, 12, and 24 h after surgery. Patients in the group N also consumed significantly smaller amounts of intraoperative opioids and morphine after surgery. Patients in the group N reported significantly fewer interruptions in sleep due to pain on the night of surgery and were able to "walk out of the bed" significantly earlier than those in the group C. There was no significant difference between the two groups in muscle strength of the quadriceps femoris or incidence of postoperative adverse effects.

CONCLUSIONS

Compared to treatment with LIA alone, ultrasound-guided transmuscular QLB combined with LIA can provide better postoperative pain relief and enhance the recovery of THA patients, since it does not cause quadriceps femoris muscle weakness and is associated with significantly lower need for intraoperative opioids.

Volume of ropivacaine 0.2% and sciatic nerve block duration: A randomized, blinded trial in healthy volunteers

BACKGROUND

Sciatic nerve blocks are used for many orthopaedic procedures on the knee, lower leg, foot and ankle. However, as nerve block durations vary considerably, the timing of supplemental analgesia is challenging. Therefore, knowledge on the effect of local anaesthetic (LA) dose on block duration is important to outweigh the benefits of increasing LA dose against the risk of LA systemic toxicity. In this randomized, double-blind trial, we aimed to explore the relationship between the volume of ropivacaine 0.2% and sciatic nerve block duration. We hypothesized that increasing LA volume would prolong block duration.

METHODS

We randomized 60 healthy volunteers to receive one of five volumes of ropivacaine 0.2%: 5, 10, 15, 20, or 30 mL. We used an ultrasound-guided, catheter-based technique targeting the sciatic nerve in the infragluteal region. The primary outcome was sensory block duration defined as the time of insensitivity to a cold stimulus. Intergroup differences were tested using one-way ANOVA.

RESULTS

Mean (SD) sensory block durations for the tibial nerve (TN) with increasing volume were: 9.3 hours (1.7), 10.4 hours (1.6), 9.7 hours (2.9), 10.7 hours (2.8) and 9.9 hours (2.6). Mean (SD) sensory block durations for the common peroneal nerve (CPN) were: 10.6 hours (2.7), 11.9 hours (1.5), 11.0 hours (3.3), 13.2 hours (3.7), and 13.5 hours (6.1). There were no intergroup differences (P = .67 [TN]; P = .25 [CPN]).

CONCLUSION

We found no effect of increasing the volume of ropivacaine 0.2% from 5 to 30 mL on sensory sciatic nerve block duration.

A Retrospective Study Evaluating the Effect of Low Doses of Perineural Dexamethasone on Ropivacaine Brachial Plexus Peripheral Nerve Block Analgesic Duration

Objective

Examination of the effectiveness of perineural dexamethasone administered in very low and low doses on ropivacaine brachial plexus block duration.

Design

Retrospective evaluation of brachial plexus block duration in a large cohort of patients receiving peripheral nerve blocks with and without perineural dexamethasone in a prospectively collected quality assurance database.

Setting

A single academic medical center.

Methods

A total of 1,942 brachial plexus blocks placed over a 16-month period were reviewed. Demographics, nerve block location, and perineural dexamethasone utilization and dose were examined in relation to block duration. Perineural dexamethasone was examined as none (0 mg), very low dose (2 mg or less), and low dose (greater than 2 mg to 4 mg). Continuous catheter techniques, local anesthetics other than ropivacaine, and block locations with fewer than 15 subjects were excluded. Associations between block duration and predictors of interest were examined using multivariable regression models. A subgroup analysis of the impact of receiving dexamethasone on block duration within each block type was also conducted using a univariate linear regression approach.

Results

A total of 1,027 subjects were evaluated. More than 90% of brachial plexus blocks contained perineural dexamethasone (≤4 mg), with a median dose of 2 mg. Increased block duration was associated with receiving any dose of perineural dexamethasone (P < 0.0001), female gender (P = 0.022), increased age (P = 0.048), and increased local anesthetic dose (P = 0.01). In a multivariable model, block duration did not differ with very low- or low-dose perineural dexamethasone after controlling for other factors (P = 0.420).

Conclusion

Perineural dexamethasone prolonged block duration compared with ropivacaine alone; however, duration was not greater with low-dose compared with very low-dose perineural dexamethasone.

Local Anesthetic Injection Speed and Common Peroneal Nerve Block Duration: A Randomized Controlled Trial in Healthy Volunteers

BACKGROUND AND OBJECTIVES

The speed of local anesthetic (LA) injections in peripheral regional anesthesia ranges from slow continuous infusions (3-12 mL/h) to rapid manual injections (>7500 mL/h). Optimizing injection speed could augment the spread of LA toward the targeted nerves and influence nerve block characteristics. The objective of this study was to investigate whether injection speed of a single dose of LA affects peripheral nerve block duration.

METHODS

After approval from the Danish Regional Scientific Ethics Committee, we enrolled 60 healthy adult volunteers. We used an ultrasound-guided catheter-based technique to perform a common peroneal nerve block. Participants were randomized to receive 4.0 mL of ropivacaine 0.2% with 1 of 5 injection speeds: 12, 60, 300, 600, or 1800 mL/h. Investigators and participants were blinded to group assignment and intervention. Primary outcome was duration of sensory nerve block defined by insensitivity toward cold. Secondary outcomes were duration of motor nerve block, time to onset of sensory nerve block, and grades of sensory and motor nerve block.Intergroup differences were tested by one-way analysis of variance.

RESULTS

We found no differences in sensory block duration between the 5 groups. Durations were median [range]: 11 [6-14], 12 [9-14], 10.5 [2-15], 11 [8-17], and 12 [9-18] hours, respectively (P = 0.294). In addition, we found no differences in secondary outcomes.

CONCLUSIONS

Injection speed of LA in the range of 12 to 1800 mL/h did not affect common peroneal nerve block duration.

CLINICAL TRIAL REGISTRATION

This study was registered at ClinicalTrials.gov, identifier NCT02801799.

Ultrasound-guided therapeutic injections for neural pathology about the foot and ankle: a 4 year retrospective review

OBJECTIVE

To describe a 4-year clinical experience with ultrasound-guided therapeutic perineural injections of peripheral nerves about the foot and ankle.

MATERIALS AND METHODS

Retrospective analysis of foot and ankle perineural injections performed between January 2012 and August 2016. Demographics, clinical indications, presence of structural pathology, immediate and interval pain relief, as well as complications were recorded.

RESULTS

Fifty-nine therapeutic injections were performed among 46 patients, accounting for multiple injections in a single visit or multiple visits [mean age = 43 years (range 18-75), 31 female (67%) and 15 male (33%)]. Most commonly, perineural injections involved the hallux branch of the medial plantar nerve (n = 17, 22%). Least commonly, perineural injections involved the saphenous nerve (n = 3, 4%). Other injections in our series include sural (10), superficial (11) and deep (7) peroneal, medial (5) and lateral (3) plantar nerves, and the posterior tibial nerve (3). Ultrasound evaluation revealed structural abnormality associated with the nerve in 30 cases (51%)-most commonly thickening with perineural scarring (n = 14). Of 45 injections with complete documentation, immediate relief of symptoms was reported in 43 (96%) cases. Interval symptom relief was achieved in 23 injections [short term (n = 12), intermediate (n = 6), and long term (n = 5)] out of 38 for which follow-up was available (61%). Complications are rare, occurring in only one case.

CONCLUSION

Ultrasound-guided perineural injections about the foot and ankle are safe and provide lasting symptomatic relief for many indications. Concomitant sonographic evaluation identifies structural abnormalities that may contribute to neuropathic symptoms, allowing targeting of injection or clinical therapy.

Use of Peripheral Nerve Blocks with Sedation for Total Knee Arthroplasty in a Patient with Contraindication for General Anesthesia

Although peripheral nerve blocks are commonly used to provide postoperative analgesia after total knee arthroplasty (TKA) and other lower extremity procedures, these blocks are rarely used for intraoperative anesthesia. Most TKAs are performed under general anesthesia (GA) or neuraxial anesthesia (NA). The knee has a complex sensory innervation that makes surgical anesthesia difficult with peripheral nerve blocks alone. Rarely are both GA and NA relatively contraindicated and alternatives are considered. We present a patient who underwent TKA performed under peripheral nerve block and sedation alone.

Noteworthy literature in regional anesthesia 2013

The regional anesthesia literature was quite active in the calendar year 2013. In typical fashion, the literature was composed of articles representing neuraxial analgesia, peripheral nerve blocks, patient outcomes, regional anesthesia adjuvant medications, and patient safety. The goal of this article is to summarize and present the most relevant articles from each of these arenas.