Mechanism of action of the erector spinae plane block: distribution of dye in a porcine model

Retrospective comparison between low-volume high-concentration and high-volume low-concentration levobupivacaine for bilateral erector spinae plane block in dogs undergoing hemilaminectomy

OBJECTIVE

To compare the analgesic effect of a bilateral ultrasound-guided erector spinae plane block (ESPB) in dogs undergoing hemilaminectomy using either a low-volume high-concentration (LV-HC) or a high-volume low-concentration (HV-LC) local anaesthetic solution.

STUDY DESIGN

Retrospective observational equivalence trial.

ANIMALS

A total of 391 client-owned dogs undergoing hemilaminectomy.

METHODS

Dogs were assigned to group LV-HC or HV-LC depending on whether 0.2-0.25% levobupivacaine (0.4-0.5 mL kg-1) or 0.125-0.15% levobupivacaine (0.8-1 mL kg-1) was used to perform the ESPB, respectively. The number of dogs in which intraoperative rescue fentanyl boluses were administered, the total dose of fentanyl administered, the overall methadone consumption during the first 24 hours postoperatively and anaesthetic complications were recorded. Univariate and multivariate statistical analyses were performed considering p < 0.05 significant.

RESULTS

A total of 248 and 143 dogs were assigned to groups LV-HC and HV-LC, respectively. In group HV-LC, the number of dogs requiring fentanyl intraoperatively (64.3%) was higher (p = 0.0001) than that in group LV-HC (43.5%). The overall intraoperative fentanyl consumption was higher in group HV-LC between the first skin incision and the end of the lamina drilling (p = 0.028). According to the regression analysis, the group allocation was the best variable to predict the intraoperative fentanyl consumption (p < 0.001). Antimuscarinic drugs were administered more frequently in group LV-HC (p < 0.02). However, the prevalence of hypotension and other pharmacological cardiovascular interventions did not differ between groups. No differences in methadone consumption during the first 24 hours postoperatively were found between the groups.

CONCLUSIONSAND CLINICAL RELEVANCE

When performing a bilateral ESPB in dogs undergoing hemilaminectomy, compared with HV-LC, the use of LV-HC local anaesthetic solution reduces the intraoperative fentanyl consumption without affecting the postoperative methadone requirement.

Erector spinae plane block in dogs undergoing hemilaminectomy: A prospective randomized clinical trial

OBJECTIVE

To compare the perioperative cumulative opioid consumption and the incidence of cardiovascular complications in dogs undergoing hemilaminectomy in which either an erector spinae plane (ESP) block or systemic opioids were administered.

STUDY DESIGN

Prospective randomized clinical trial.

ANIMALS

A total of 60 client-owned dogs.

METHODS

Dogs were randomized to one of three groups: an ESP block (group ESP), a constant rate infusion of fentanyl (group FNT, positive control) or a single dose of methadone as premedication (group MTD, negative control). Intraoperative nociceptive response was treated with fentanyl [1 μg kg-1, intravenously (IV)] boli. Before closure of the surgical site, morphine (0.1 mg kg-1) was applied to the dura mater. The cumulative dose of opioids was recorded and compared between groups. The incidence of intraoperative bradycardia and/or hypotension and the time to extubation were compared between groups. The short form of the Glasgow Composite Pain Scale (SF-GCPS) was used to score nociception before anaesthetic induction and 1, 2, 6, 12,18 and 24 hours postoperatively. Methadone 0.2 mg kg-1 was administered IV if the SF-GCPS score was ≥ 5.

RESULTS

Group MTD required more intraoperative rescue analgesia than groups ESP (p = 0.008) and FNT (p = 0.001). The total cumulative intraoperative dose of fentanyl was higher in groups FNT (p < 0.0001) and MTD (p = 0.002) than in group ESP. The incidence of cardiovascular complications was similar between groups. Extubation time was longer in group MTD (p = 0.03). Postoperatively, the time to first rescue analgesia was longer in group ESP than in group MTD (p = 0.03). The cumulative postoperative opioid consumption and pain scores were similar between groups.

CONCLUSIONS AND CLINICAL RELEVANCE

The ESP block resulted in a reduced intraoperative opioid consumption compared with the control positive and negative groups.

Effect of liposomal bupivacaine for preoperative erector spinae plane block on postoperative pain following video-assisted thoracoscopic lung surgery: a protocol for a multicenter, randomized, double-blind, clinical trial

Background

There is still a controversy about the superiority of liposomal bupivacaine (LB) over traditional local anesthetics in postoperative analgesia after thoracic surgery. This study aims to determine the effect of LB versus bupivacaine hydrochloride (HCl) for preoperative ultrasound-guided erector spinae plane block (ESPB) on postoperative acute and chronic pain in patients undergoing video-assisted thoracoscopic lung surgery.

Methods

This multicenter, randomized, double-blind, controlled trial will include 272 adult patients scheduled for elective video-assisted thoracoscopic lung surgery. Patients will be randomly assigned, 1:1 and stratified by site, to the liposomal bupivacaine (LB) group or the bupivacaine (BUPI) HCl group. All patients will receive ultrasound-guided ESPB with either LB or bupivacaine HCl before surgery and patient-controlled intravenous analgesia (PCIA) as rescue analgesia after surgery. The numeric rating scale (NRS) score will be assessed after surgery. The primary outcome is the area under the curve of pain scores at rest for 0-72 h postoperatively. The secondary outcomes include the total amount of opioid rescue analgesics through 0-72 h postoperatively, time to the first press on the PCIA device as rescue analgesia, the area under the curve of pain scores on activity for 0-72 h postoperatively, NRS scores at rest and on activity at different time points during the 0-72 h postoperative period, Quality of Recovery 15 scores at 72 h after surgery, and NRS scores on activity on postsurgical day 14 and postsurgical 3 months. Adverse events after the surgery are followed up to the postsurgical day 7, including postoperative nausea and vomiting, fever, constipation, dizziness, headache, insomnia, itching, prolonged chest tube leakage, new-onset atrial fibrillation, severe ventricular arrhythmia, deep venous thrombosis, pulmonary embolism, pulmonary atelectasis, cardiac arrest, ileus, urinary retention, chylothorax, pneumothorax, and organ failure. Analyzes will be performed first according to the intention to treat principle and second with the per-protocol analysis.

Discussion

We hypothesize that LB for preoperative ultrasound-guided ESPB would be more effective than bupivacaine HCl in reducing postoperative pain in video-assisted thoracoscopic lung surgery. Our results will contribute to the optimization of postoperative analgesia regimens for patients undergoing video-assisted thoracoscopic lung surgery.Clinical trial registration:http://www.chictr.org.cn, identifier ChiCTR2300074852.

Cadaveric study of the ultrasound-guided erector spinae plane block over the transverse process of the twelfth thoracic vertebra in dogs: Transversal vs longitudinal approach

This study describes a transversal (TV) ultrasound-guided erector spinae plane (ESP) block technique over the transverse process of T12. And evaluates the distribution of the dye and affected nerves branches compared to a longitudinal (LNG) approach over the transverse process of T12 in canine cadavers. Secondly, it also compares de anatomy and dimensions of the transverse processes of T12 with T9 and T5. For this double-masked, cadaveric experimental study, 12 adult Beagle cadavers were injected with 0.6 mL/kg of dye/contrast. Spread was evaluated by computed tomography (CT) and dissection. Mean bodyweight was 9.76 (±0.59) kg. The TV and LNG approaches stained a median (range) of four (2-6) and three (1-6) medial branches of the dorsal rami of the spinal nerves, three (2-6) and three (2-5) lateral branches, and one (0-3) and one (0-4) ventral branches, respectively. Dye was detected in the epidural space in 55.6% and 66.7% of cases for the TV and LNG approaches, respectively (P=0.63). And in the ventral paravertebral compartment in 22.2% and lymphatics in 88.8% in both approaches. There were no statistical differences for the spread. The dorsolateral edge of the transverse process (TP) was not visible with CT at T12. The mean (±SD) length of the TP was significantly shorter at T12 [3.34 (±0.22)] mm, compared to T9 [6.08 (±0.47)] mm and T5 [5.93 (±0.62)] mm (P <0.001). This study showed similar distribution whether using a TV or LNG approach and differences in the anatomy and length of the T12 TP.

Pathways of dye spread after injections in the paraspinal spaces-A cadaveric study

Background

The erector spinae plane (ESP) block is the most sought-after block since its inception. However, it is more of dorsal rami block with unpredictable ventral diffusion to the paravertebral area. We injected dye in ESP and other paraspinal spaces to study and compare the dye diffusion pattern along the neuroaxis and paraspinal region in human cadavers.

Methods

In six soft-embalmed cadavers (12 specimens), 20 mL methylene blue dye (erector spinae plane and paravertebral space) or indocyanine green dye (inter-ligament space) was injected bilaterally using an in-plane ultrasound-guided technique at the level of the costotransverse junction of fourth thoracic vertebrae. Dye spread was evaluated bilaterally in the coronal plane in the paravertebral and intercostal spaces from the 1st and the 12th rib. Axial and sagittal sections were performed at the level of the 4th thoracic vertebrae. After cross sections, the extent of dye spread was investigated in ESP, inter-ligament, and paravertebral spaces. The staining of the ventral and dorsal rami and spread into the intercostal spaces was evaluated.

Results

ESP injection was mainly restricted dorsal to the costotransverse foramen and did not spread anteriorly to the paravertebral space. The paravertebral injection involved the origin of the spinal nerve and spread laterally to the intercostal space. The inter-ligament space injection showed an extensive anterior and posterior dye spread involving the ventral and dorsal rami.

Conclusions

Following ESP injection, there was no spread of the dye anteriorly to the paravertebral space and it only involved the dorsal rami. Inter-ligamentous space injection appears to be the most promising block as dye spread both anteriorly to paravertebral space and posteriorly toward ESP.

Differential nerve blockade to explain anterior thoracic analgesia without sensory blockade after an erector spinae plane block may be wishful thinking

Ultrasound-guided erector spinae plane block (ESPB) is currently used as a component of multimodal analgesic regimen in a multitude of indications but the mechanism by which it produces anterior thoracic analgesia remains a subject of controversy. This is primarily the result of ESPB's failure to consistently produce cutaneous sensory blockade (to pinprick and cold sensation) over the anterior hemithorax. Nevertheless, ESPB appears to provide 'clinically meaningful analgesia' in various clinical settings. Lately, it has been proposed that the discrepancy between clinical analgesia and cutaneous sensory blockade could be the result of differential nerve blockade at the level of the dorsal root ganglion. In particular, it is claimed that at a low concentration of local anesthetic, the C nerve fibers would be preferentially blocked than the Aδ nerve fibers. However, the proposal that isolated C fiber mediated analgesia with preserved Aδ fiber mediated cold and pinprick sensation after an ESPB is unlikely, has never been demonstrated and, thus, without sufficient evidence, cannot be attributed to the presumed analgesic effects of an ESPB.

Fascial plane blocks in children-Scientifically supported or not?

Since the introduction of Fascial Plane Blocks in 2007 there has been an enormous interest and application of Fascial Plane Blocks, evidenced by substantially more than 1000 PubMed items. Despite this gigantic number of publications, also including randomized controlled trials and meta-analyses in children, there is still no clear-cut insight into how much of the purported effect is in fact due to the blockade of nerve structures and how much is merely adding the well-known analgesic and anti-inflammatory effects of the plasma levels of local anesthetics that are achieved with these techniques. Furthermore, Fascial Plane Blocks appear useful only if compared to conventional multi-modal analgesia (no block or placebo) and Fascial Plane Blocks lack the potency to provide surgical anesthesia on their own and appear only to be of value when used for minor-moderate surgery. Despite the huge literature, there has so far not emerged any clinical situations where Fascial Plane Blocks have definitively been shown to be the block of choice, being decisively more effective than other established regional blocks. Lastly, Fascial Plane Blocks may appear as virtually free of complications, but case reports are emerging that point to a real risk for causing local anesthetic systemic toxicity when using Fascial Plane Blocks. This text aims to synthesize the current knowledge base regarding the Fascial Plane Blocks that are relevant to use in the pediatric context. In summary, there does currently not exist any convincing scientific evidence for the continued support for the use of Fascial Plane Blocks in children, except for the rectus sheath block and possibly also the transmuscular quadratus lumborum block.

Analgesic efficacy of an opioid-free postoperative pain management strategy versus a conventional opioid-based strategy following open major hepatectomy: an open-label, randomised, controlled, non-inferiority trial

Background

Convincing clinical evidence regarding completely opioid-free postoperative pain management using erector spinae plane block (ESPB) in patients undergoing open major hepatectomy (OMH) is lacking. Herein, we aimed to compare the postoperative analgesic efficacy of the visualised continuous opioid-free ESPB (VC-ESPB) and conventional intravenous opioid-based postoperative pain management in hepatocellular carcinoma (HCC) patients undergoing OMH.

Methods

This open-label, randomised, controlled, non-inferiority trial enrolled patients with HCC undergone open major hepatectomy in Fujian Provincial Hospital and compared the postoperative analgesic efficacy of VC-ESPB (VC-ESPB group) and conventional intravenous opioid-based pain management regimen (conventional group). Patients were randomly assigned (1:1) to VC-ESPB group and conventional group. Patients were not masked to treatment allocation. The VC-ESPB group was treated with intermittent injections of 0.25% ropivacaine (bilateral, 30 mL each side) given every 12 h through catheters placed in the space of erector spinae and an opioid-free intravenous pump (10-mg tropisetron diluted to 100 mL with 0.9% normal saline [NS]) for postoperative pain management. The conventional group did not receive ESPB and was treated with a conventional intravenous opioid-based pump (2.5-μg/kg sufentanil and 10-mg tropisetron diluted to 100 mL with 0.9% NS). Patients in the VC-ESPB group underwent magnetic resonance imaging (MRI) to identify local anaesthetic diffusion after ESPB was performed under ultrasound guidance. The primary outcome was postoperative analgesic efficacy, which was indicated by the cumulative area under the curve (AUC) of the pain visual analogue scale scores (range, 0-10; a higher score indicates more pain) obtained at rest and at movement until 48 h postoperatively after leaving the post-anaesthesia care unit (PACU). Herein, an AUC of 26.5 was set as the noninferiority margin, which needed to be satisfied for both cumulative AUCPACU-48 h at rest and cumulative AUCPACU-48 h at movement. Per protocol participants were included in primary and safety analyses. This trial was registered with ChiCTR.org.cn (ChiCTR1900026583).

Findings

Between October 30, 2019, and May 1, 2023, 106 patients were enrolled and randomly assigned to the VC-ESPB group (n = 53) and the conventional group (n = 53). After the dropout (n = 5), a total of 101 patients (VC-ESPB group, n = 50; conventional group, n = 51) were analysed. Both the level of cumulative AUCPACU-48 h (at rest: 160.08 ± 38.00 vs. 164.94 ± 31.00; difference [90% CI], -4.861 [-16.308, 6.585]) and cumulative AUCPACU-48 h (at movement: 209.64 ± 28.98 vs. 212.59 ± 33.11; difference [90% CI], -2.948 [-13.236, 7.339]) were similar between the VC-ESPB and control groups within the first postoperative 48 h. The upper limit of the 90% CIs for the difference in cumulative ACUPACU-48 h at rest and at movement did not reach the upper inferiority margin (26.5). During the first postoperative 48 h, the rate of nonsteroidal anti-inflammatory drug rescue analgesia was similar between the VC-ESPB group and conventional group (n = 16, 32.0% vs. n = 11, 21.6%; P = 0.236). Treatment-related death was not observed in the VC-ESPB group (n = 0, 0%) and conventional group (n = 0, 0%). In VC-ESPB group, local site paralysis (n = 1, 2.0%) was observed in one patient and rash (n = 1, 2.0%) was observed in another patient. One patient in the conventional group was observed with rash preoperatively (n = 1, 2.0%). The VC-ESPB group had significantly lower rates of postoperative nausea (n = 2, 4.0%, vs. n = 9, 17.6%, P = 0.028), vomiting (n = 1, 2.0% vs. n = 8, 15.7%, P = 0.031) and lower incidence of major complications (n = 4, 8.0% vs. n = 6, 11.8%; P = 0.033).

Interpretation

This study demonstrates the noninferiority of VC-ESPB when compared with the conventional opioid-based approach for postoperative pain management after OMH, suggesting that it is feasible to achieve opioid-free postoperative pain management for OMH.

Funding

The Joint Funds for the Innovation of Science and Technology, Fujian Province, China; the Youth Scientific Research Project of Fujian Provincial Health Commission; the Fujian Research and Training Grants for Young and Middle-aged Leaders in Healthcare; and the Key Clinical Specialty Discipline Construction Program of Fujian, China.

Erector spinae plane block for postoperative analgesia in robotically-assisted coronary artery bypass surgery: Results of a randomized placebo-controlled trial

STUDY OBJECTIVE

To investigate if an erector spinae plane (ESP) block decreases postoperative opioid consumption, pain and postoperative nausea and vomiting in patients undergoing robotically-assisted minimally invasive direct coronary artery bypass surgery (RAMIDCAB).

DESIGN

A single-center, double-blind, prospective, randomized, placebo-controlled trial.

SETTING

Postoperative period; operating room, post-anesthesia care unit (PACU) and hospital ward in a university hospital.

PATIENTS

Sixty-four patients undergoing RAMIDCAB surgery via left-sided mini-thoracotomy and enrolled in the institutional enhanced recovery after cardiac surgery program.

INTERVENTIONS

At the end of surgery, patients received an ESP catheter at vertebra T5 under ultrasound guidance and were randomized to the administration of either ropivacaine 0.5% (loading dose of 30 ml and three additional doses of 20 ml each, interspersed with a 6 h interval) or normal saline 0.9% (with an identical administration scheme). In addition, patients received multimodal analgesia including acetaminophen, dexamethasone and patient-controlled analgesia with morphine. Following the final ESP bolus and before catheter removal, the position of the catheter was re-evaluated by ultrasound. Patients, investigators and medical personnel were blinded for the group allocation during the entire trial.

MEASUREMENTS

Primary outcome was cumulative morphine consumption during the first 24 h after extubation. Secondary outcomes included location and severity of pain, presence/extent of sensory block, duration of postoperative ventilation and hospital length of stay. Safety outcomes comprised the incidence of adverse events.

MAIN RESULTS

Median (IQR) 24-h morphine consumption was not different between the intervention- and control-groups, 67 mg (35-84) versus 71 mg (52-90) (p = 0.25), respectively. Likewise, no differences were detected in secondary and safety endpoints.

CONCLUSIONS

Following RAMIDCAB surgery, adding an ESP block to a standard multimodal analgesia regimen did not reduce opioid consumption and pain scores.

Efficacy of erector spinae plane block for minimally invasive mitral valve surgery: Results of a double-blind, prospective randomized placebo-controlled trial

STUDY OBJECTIVE

To investigate if an erector spinae plane (ESP) block decreases postoperative opioid consumption, pain and postoperative nausea and vomiting in patients undergoing minimally invasive mitral valve surgery (MIMVS).

DESIGN

A single-center, double-blind, prospective, randomized, placebo-controlled trial.

SETTING

Postoperative period; operating room, post-anesthesia care unit (PACU) and hospital ward in a university hospital.

PATIENTS

Seventy-two patients undergoing video-assisted thoracoscopic MIMVS via right-sided mini-thoracotomy and enrolled in the institutional enhanced recovery after cardiac surgery program.

INTERVENTIONS

At the end of surgery, all patients received an ESP catheter at vertebra T5 under ultrasound guidance and were randomized to the administration of either ropivacaine 0.5% (loading of dose 30 ml and three additional doses of 20 ml with a 6 h interval) or normal saline 0.9% (with an identical administration scheme). In addition, patients received multimodal postoperative analgesia including dexamethasone, acetaminophen and patient-controlled intravenous analgesia with morphine. Following the final ESP bolus and before catheter removal, the position of the catheter was re-evaluated by ultrasound. Patients, investigators and medical personnel were blinded for the group allocation during the entire trial.

MEASUREMENTS

Primary outcome was cumulative morphine consumption during the first 24 h after extubation. Secondary outcomes included severity of pain, presence/extent of sensory block, duration of postoperative ventilation and hospital length of stay. Safety outcomes comprised the incidence of adverse events.

MAIN RESULTS

Median (IQR) 24-h morphine consumption was not different between the intervention- and control-group, 41 mg (30-55) versus 37 mg (29-50) (p = 0.70), respectively. Likewise, no differences were detected for secondary and safety endpoints.

CONCLUSIONS

Following MIMVS, adding an ESP block to a standard multimodal analgesia regimen did not reduce opioid consumption and pain scores.

Management of thoracic trauma

Managing major thoracic trauma begins with identifying and anticipating injuries associated with the mechanism of injury. The key aims are to reduce early mortality and the impact of associated complications to expedite recovery and restore the patient to their pre-injury state. While imaging is imperative to identify the extent of thoracic trauma, some pathology may require immediate treatment. The majority can be managed with adequate pleural drainage, but respiratory failure and poor gas exchange may require either non-invasive or invasive ventilation. Ventilation strategies to protect from complications such as barotrauma, volutrauma and ventilator-induced lung injury are important to consider. The management of pain is vital in reducing respiratory complications. A multimodal strategy using local, regional and systemic analgesia may mitigate respiratory side effects of opioid use. With optimal pain management, physiotherapy can be fully utilised to reduce respiratory complications and enhance early recovery. Thoracic surgeons should be consulted early for consideration of surgical management of specific injuries. With a greater understanding of the mechanisms of injury and the appropriate use of available resources, favourable outcomes can be reached in this cohort of patients. Overall, a multidisciplinary and holistic approach results in the best patient outcomes.

Bilateral ultrasound-guided erector spinae plane block versus wound infiltration for postoperative analgesia in lumbar spinal fusion surgery: a randomized controlled trial

PURPOSE

Both erector spinae plane block and wound infiltration are used to improve analgesia following spinal fusion surgery. Herein, we compared the analgesic effect of bilateral erector spinae plane block with wound infiltration in this patient population.

METHODS

In this randomized trial, 60 patients scheduled for elective open posterior lumbar interbody fusion surgery were randomized to receive either ultrasound-guided bilateral erector spinae plane block before incision (n = 30) or wound infiltration at the end of surgery (n = 30). Both groups received standardized general anesthesia and postoperative analgesia, including patient-controlled analgesia with sufentanil and no background infusion. Opioid consumption and pain intensity were assessed at 2, 6, 12, 24, and 48 h after surgery. The primary outcome was cumulative opioid consumption within 24 h after surgery.

RESULTS

All 60 patients were included in the intention-to-treat analysis. The equivalent dose of sufentanil consumption within 24 h was significantly lower in patients given erector spinae plane block (median 11 μg, interquartile range 5-16) than in those given wound infiltration (20 μg, 10 to 43; median difference - 10 μg, 95% CI - 18 to - 3, P = 0.007). The cumulative number of demanded PCA boluses was significantly lower with erector spinae plane block at 6 h (median difference - 2, 95% CI - 3 to 0, P = 0.006), 12 h (- 3, 95% CI - 6 to - 1, P = 0.002), and 24 h (- 5, 95% CI - 8 to - 2, P = 0.005) postoperatively. The proportion given rescue analgesia was also significantly lower in patients given erector spinae plane block group within 48 h (relative risk 0.27, 95% CI 0.07 to 0.96, P = 0.037). There were no statistical differences in pain intensity at any timepoints between groups. No procedure-related adverse events occurred.

CONCLUSIONS

Compared with wound infiltration, bilateral ultrasound-guided erector spinae plane block decreases short-term opioid consumption while providing similar analgesia in patients following lumbar spinal fusion surgery. Chinese Clinical Trial Registry: ChiCTR2100053008.

Analgesic efficacy of a bilateral erector spinae plane block versus a fentanyl constant rate infusion in dogs undergoing hemilaminectomy: a retrospective cohort study

BACKGROUND

Erector spinae plane block (ESPB) is an ultrasound-guided interfascial plane block used to provide analgesia in dogs undergoing hemilaminectomy. The aim of this study is to compare the analgesic efficacy of a bilateral ESPB with a fentanyl constant rate infusion (CRI) in dogs undergoing hemilaminectomy.

METHODS

This is a retrospective cohort study. Anaesthetic records of client-owned dogs undergoing hemilaminectomy (June 2019-August 2020), and in which a bilateral ESPB was performed (group ESPB), were retrieved and compared to a cohort of 39 dogs that underwent hemilaminectomy (September 2014 - June 2017) and in which a fentanyl CRI (2 μg/kg bolus followed by 5 μg/kg/hour) was used as a primary intraoperative analgesia (group CRI). The prevalence of dogs in which intraoperative rescue fentanyl boluses were administered, the total dose of rescue fentanyl boluses administered, the postoperative methadone requirement and anaesthetic complications during the first 24 postoperative hours were evaluated. Univariate statistical analysis was used.

RESULTS

Group ESPB comprised of 93 dogs. The bilateral ESPB was performed using a median (range) levobupivacaine volume of 1 (0.5-1.7) mL/kg per side, at a concentration of 0.125% (0.12-0.25). At least one rescue fentanyl bolus was administered in 54.8% and in 56.4% of dogs in group ESPB and CRI, respectively (p > 0.99). The number of rescue fentanyl boluses was higher in group CRI (p = 0.006), especially during lumbar hemilaminectomy. Rescue fentanyl boluses were more frequently administered from skin incision to end of vertebral lamina drilling in group CRI (p = 0.001), and from end of vertebral lamina drilling to end of surgery in group ESPB (p = 0.0002). During the first 6 (p = 0.0035) and 6-12 (p = 0.0005) postoperative hours, the number of dogs that required at least one dose of methadone was higher in group CRI. In group ESPB, dogs were more likely to become hypothermic (p = 0.04). One dog, not included in the study, developed sinus arrest after performing a caudal thoracic ESPB.

CONCLUSIONS

Under the conditions of this study, a bilateral ESPB was associated with a lower number of rescue fentanyl boluses administered in dogs undergoing hemilaminectomy, especially between skin incision to end of vertebral lamina drilling. Despite ESPB being associated with a reduced opioid consumption during the first 12 hours postoperatively, differences in the postoperative management precluded any firm conclusion regarding its postoperative effect.

Description of an Ultrasound-Guided Erector Spinae Plane Block and Comparison to a Blind Proximal Paravertebral Nerve Block in Cows: A Cadaveric Study

Simple Summary

One of the most common surgical procedures performed in cattle is abdominal surgery, and this procedure is routinely performed in the standing adult animal. This procedure is performed using local anaesthetic techniques in order to eliminate pain and reduce the need for chemical and physical restraints. One of the most common locoregional anaesthetic techniques is the proximal paravertebral nerve block, in which a local anaesthetic is used to desensitize the nerves providing sensation to the flank region. The use of ultrasound-guided techniques has been demonstrated in multiple species, including humans, to be more accurate, safe and efficacious than traditional blind techniques. The aim of this paper was to develop an ultrasound-guided block that would target the nerves desensitized in the paravertebral nerve block of the flank. Additionally, our study aimed to evaluate the two techniques (blind and ultrasound-guided) in cow cadavers. The use of ultrasound guidance resulted in an apparent improvement in accuracy, and the blind technique remains a reliable approach. Further studies are warranted to develop and to evaluate the ultrasound-guided technique in live animals.

Abstract

The proximal paravertebral nerve block is commonly used to provide anaesthesia to the flank during standing surgical procedures in adult cattle. It has been reported that additional anaesthetic infiltration may be necessary to provide complete anaesthesia. In humans as well as animal species, another technique—the ultrasound (US)-guided erector spinae plane block (ESPB)—has been described. The goal of the present study was to develop and investigate an US-guided ESPB in comparison to a blind proximal paravertebral nerve block (PPNB) in cow cadavers. In 10 cadaver specimens, injections of methylene blue-lidocaine (1:1) were performed at the level of T13, L1 and L2 vertebras, on one side doing an ESPB block and, on the other side, a PPNB. Five cadavers were injected with high (40 mL per injection for PPNB and 20 mL for ESPB) and five with low (20 and 15 mL, respectively) volumes of injectate. For the ESPB, the ultrasound probe was oriented craniocaudally, and the ventral-cranial aspect of the articular processes (T13, L1 and L2) was targeted for injection. The dye spreading was evaluated by dissection. The landmarks for US-guided injection were easily visualized; however, injections were accidentally performed at T12, T13 and L1. Nevertheless, L2 was stained in 60% of ESPBs. Epidural spreading was observed with both techniques and all volumes. Viscera puncture was reported in two PPNBs. The ESPB resulted in similar nerve staining compared to the PPNB while using a lower volume of injectate. Even better staining is expected with a T13-L2 instead of a T12-L1 ESPB approach. Further studies are warranted to evaluate the clinical efficacy.

Ultrasound-guided bilateral erector spinae plane block in dogs undergoing sternotomies anaesthetised with propofol-dexmedetomidine continuous infusion

BACKGROUND

To describe the use of a bilateral thoracic (T5 - T9) ultrasound-guided erector spinae plane block (UG-ESPB) in dogs undergoing sternotomy anaesthetised with propofol and dexmedetomidine continuous infusions.

METHODS

Demographic information, perioperative anaesthetic and analgesic drugs, the prevalence of hypotension and nociceptive events, and their treatment, were recorded and analysed. Local anaesthetic injection point, volume and concentration were reported for each dog. In attempt to differentiate somatic nociception from visceral nociception, the surgery was divided into three timeframes: from the skin incision to the thoracic cavity opening; from the latter to the beginning of its closure; from thoracic cavity closure to the end of surgery.

RESULTS

Overall, 10 dogs were included and four experienced nociception: somatic nociception was recorded in one dog, whereas visceral nociception was recorded in four dogs. The overall fentanyl consumption to control nociception was 0.3 µg/kg/h. No adverse events associated with the UG-ESPB were reported.

CONCLUSION

The bilateral UG-ESPB could be used as a part of a multimodal analgesic technique in dogs undergoing sternotomies. However, more clinical studies are warranted to assess its safety and effects.

Local and Regional Anaesthetic Techniques in Canine Ovariectomy: A Review of the Literature and Technique Description

Simple Summary

This review stems from a general trend of increasing attention toward surgical nociception in the veterinary field. Indeed, veterinarian anaesthetists are becoming more careful in relieving perioperative nociception, improving the analgesic protocols and therefore optimising surgical outcomes. Canine ovariectomy is a common surgical procedure with a moderate level of pain. Therefore, intraoperative analgesia is very important because pain causes various systemic inflammatory effects that slow patient recovery. This review aims to collect all recent information about local and regional anaesthetic/analgesic techniques in a review of the literature describing the technique utilised. In addition, the present review aims to provide practical guidelines for veterinary practitioners to improve the anaesthetic techniques in canine neutering through an overview of the available literature. In fact, the methods described, considering the relative simplicity of execution, can be used in daily routine practice.

Abstract

Canine ovariectomy is an elective surgery with a moderate level of pain. Despite its relative simplicity, it requires surgical pain management. This study aimed to collect all recent information about local and regional anaesthetic/analgesic techniques in a review of the literature describing the technique utilised. The various procedures described in this review use local anaesthetics to improve analgesia in the routine systemic anaesthetic protocol. The approach described in this paper is called multimodal analgesia and is used in addition to the normal standard anaesthetic protocol. These techniques proved effective in minimising responses to the surgical stimulus and ensured adequate intraoperative and postoperative analgesia. The routine use of multimodal analgesia is considered a useful alternative for pain management in canine ovariectomy, in that it minimises patient suffering, improves the recovery of rescue analgesia, increases drug savings, and improves animal outcomes. In addition, the use of these local and regional techniques ensures satisfactory analgesic coverage that lasts for the first hours postoperatively.

Ultrasound-guided erector spinae plane block for postoperative analgesia in patients after liver surgery: A systematic review and meta-analysis on randomized comparative studies

OBJECTIVE

To compare the analgesic efficacy and feasibility of erector spinae plane block (ESPB) with non-block care or other blocks in patients undergoing liver surgery.

METHOD

A meta-analysis of randomized controlled trials (RCTs) that compared ESPB to non-block care or local infiltration analgesia (LIA), intrathecal morphine (ITM) and quadratus lumborum block (QLB) for postoperative analgesia in liver surgery patients.

RESULTS

Six RCTs containing 392 patients were included. This meta-analysis found that ESPB did not significantly reduce postoperative 8 h [mean standard (MD) 0.20; 95% (confidence interval) CI: -1.62, 2.01; P = 0.83; I² = 99%] and 24 h [MD 0.10; 95% CI: -0.91, 1.11; P = 0.84; I² = 97%] resting pain scores in patients undergoing liver surgery compared to control groups. Furthermore, ESPB had no effect on postoperative 24 h cumulative opioid consumption [MD 1.74; 95% CI: 3.43, 6.91; P = 0.51; I² = 95%] or sleep quality [OR 1.00; 95% CI: 0.43, 2.35; P 0.99; I² = 0%]. In contrast, ESPB reduced postoperative 48 h resting pain score [MD -0.77; 95% CI -1.56, 0.02; P = 0.05; I² = 96%], the incidence of postoperative nausea and vomiting (PONV) [OR 0.29; 95% CI 0.18, 0.48; P = 0.001; I² = 0%]. Interestingly, in two RCTs, ESPB showed a higher incidence of shoulder pain compared to ITM [OR 2.89; 95%CI 1.03 to 8.09; P = 0.04; I² = 0%]. There have been no reports of complications from ESPB or other blocks.

CONCLUSION

Current literature supported that ESPB had no significant difference in analgesic efficacy in liver surgery patients compared to LIA, ITM, and QLB. More evidences, preferably from high quality RCTs are required to confirm these finding.

Erector Spinae Plane Block: A Novel Anesthetic Approach for Pleuroscopy

BACKGROUND

Anesthesia and analgesia for thoracic procedures, specifically pleuroscopy, present unique challenges given the spectrum of underlying pulmonary disease and susceptibility to respiratory complications. This study describes efforts to reduce postoperative pain and minimize opioid analgesia after thoracoscopic procedures through the use of erector spinae plane block (ESPB).

METHODS

This is a single center, retrospective case series of all patients who underwent rigid pleuroscopy with ESPB plus monitored anesthesia care (MAC) from November 2018 through September 2020. The primary outcome measures were postoperative pain scores and analgesic medication requirements.

RESULTS

Twenty-six patients underwent pleuroscopy with ESPB plus MAC. Average intraoperative and postoperative opioid consumption in oral morphine equivalents were 18.4±15.8 and 11.2±19.6 mg, respectively. There was no significant difference between average preoperative and postoperative subjective numerical pain scores (P=0.221). There were no complications associated with ESPB.

CONCLUSION

This case series demonstrates the feasibility of utilizing single shot ESPB in combination with MAC as the primary anesthetic for thoracoscopic procedures.

Opioid-sparing effects of ultrasound-guided erector spinae plane block for adult patients undergoing surgery: A systematic review and meta-analysis

BACKGROUND

Erector spinae plane block (ESPB) is a new method of administering analgesics to patients perioperatively. The aim of this meta-analysis was to evaluate the opioid-sparing effects of erector spinae plane block in patients during the perioperative period compared to conventional analgesia and identify its role in the development of opioid-free anesthesia.

METHODS

Relevant study articles were retrieved from PubMed, the Web of Science, Medline via Ovid, Embase via Ovid, and the Cochrane Central Register of Controlled Trials (CENTRAL) on June 11, 2020. We included randomized controlled trials (RCTs) comparing the use of ESPB with control (no/sham block). The primary outcome was opioid consumption at 24 h after surgery and intraoperative opioid consumption. A random-effects model was used to calculate the standardized mean difference (SMD) and odds ratio (OR) with 95% confidence interval (CI) if there was significant heterogeneity in the data; otherwise, the fixed-effect model was used.

RESULTS

A total of 25 randomized controlled trials involving 1461 patients were included. The use of ultrasound-guided ESPB was associated with reduced opioid consumption at 24 h after surgery [SMD: -2.14, 95% CI: -2.61 to -1.67, p < 0.001] and during the intraoperative period [SMD: -2.30, 95% CI: -3.21 to -1.40, p < 0.001]. In addition, it took a longer time to administer the first rescue analgesia in the ESPB group [SMD: 3.60, 95% CI: 2.23-4.97, p < 0.001] and the group was associated with lower incidences of postoperative nausea or vomiting (PONV) [OR: 0.50, 95% CI: 0.34-0.72, p < 0.001].

CONCLUSIONS

Ultrasound-guided ESPB could provide an opioid-sparing effect and effective analgesia in adults undergoing surgeries with general anesthesia, and then promote opioid-free anesthesia development.

Ultrasound-guided erector spinae interfascial plane block for spinal surgery in three cats

Case series summary

The erector spinae plane (ESP) block consists of an interfascial injection of local anaesthetic between the erector spinae muscle group and the transverse processes of the thoracic vertebrae. This block targets the dorsal rami of the thoracic spinal nerves to desensitise the cutaneous area near the dorsal midline, the paraspinal muscles, the dorsal vertebral laminae and the facet joints. The purpose of this case series is to describe the perioperative analgesic effect and complications of ultrasound-guided ESP block with bupivacaine in three cats undergoing spinal surgery. Only one cardiovascular response was recorded in this case series. Just one cat received intraoperative rescue analgesia. Cats 1 and 2 recorded just one high pain score in the first 24 h postoperatively, and cat 3 recorded three high pain scores. The total amount of methadone given in the 24 h postoperatively was 0.6 mg/kg in cat 1, 0.9 mg/kg in cat 2 and 0.8 mg/kg in cat 3. All three cats suffered mild and transient intraoperative complications, which were easily addressed. There were no postoperative complications.

Relevance and novel information

This case series documents a novel locoregional anaesthesia technique as an alternative to traditional systemic analgesia. The technique is part of a multimodal analgesia approach for spinal surgery in cats. Perioperative analgesic effect and complications presented in this case series are evaluated and discussed.

Axillary ultrasound-guided approach for the brachial plexus in pig cadavers: A descriptive study

Effective multimodal analgesia techniques are required when pigs are used as models in orthopedic human research. Regional anesthesia is a widely used technique to provide perioperative analgesia in animals undergoing orthopedic surgery. The brachial plexus (BP) block is indicated to desensitize the forelimb in many species but has not been yet described in pigs. The main aims of this study were to develop an ultrasound-guided axillary approach for the BP and to evaluate injectate spread and nerve staining in pig cadavers. Eight fresh F1 cross breed German Large White and German Landrace male pig cadavers were enrolled. Two cadavers were used for anatomical dissection of the axillary space and to determine the disposition of the BP. Six cadavers were used to perform a bilateral axillary ultrasound-guided approach for the BP, and after injecting 0.3 ml/kg of a solution of 2% lidocaine and new methylene blue (L-NMB), these were dissected to determine injectate spread and nerve staining. Upon dissection, the BP was observed in all the cases surrounded by the axillary sheath and in close proximity to the axillary artery. Ultrasonographic scanning and guidance for the approach to the BP was feasible in all cadavers and upon dissection, all the nerves forming the BP were stained in all their quadrants and in all the cases. In conclusion, the injection of 0.3 ml/kg of L-NMB through an ultrasound-guided axillary approach to the BP was feasible and adequate to entirely stain the BP in all pig cadavers. Further clinical studies are required to evaluate the effectiveness of this technique in live animals.

Postoperative pain: a review of emerging therapeutic options

INTRODUCTION

Postoperative pain is often managed by opioid medications, even though they carry a risk of adverse effects such as vomiting, constipation, sedation, respiratory depression and physical dependence. Furthermore, opioid use in the healthcare setting has likely contributed to the epidemic. However, the mismanagement of postoperative pain can result in delayed recovery time, impaired physical function, increased risk of morbidity and mortality, chronic pain, and higher healthcare costs.

AREAS COVERED

This review explores emerging therapeutic options and strategies in the management of acute postoperative pain and focuses on opioid-sparing, multimodal analgesia. This includes regional anesthetic techniques, non opioid pharmacotherapy, novel opioids and non-pharmacologic therapy. We have also discussed examples of novel analgesics and formulations which have potential benefits in reducing postoperative pain and opioid use after surgery.

EXPERT OPINION

The development of novel regional anesthesia techniques allows for opioid minimization in increasing number of surgical procedures. This synergizes with the availability of novel non-opioid analgesic adjucts. In addition, several novel opioid drugs have been developed which may be pathway selective and associated with less adverse effect than conventional opioids.

High Thoracic Erector Spinae Plane Block for Arthroscopic Shoulder Surgery: A Randomized Prospective Double-Blind Study

OBJECTIVE

Moderate to severe pain may occur following arthroscopic shoulder surgery. An erector spinae plane block (ESPB) may be used for painful conditions of the shoulder. The primary hypothesis of this trial is that ultrasound-guided ESPB would provide effective analgesia by reducing opioid consumption. The secondary hypothesis is that ESPB would result in low pain scores and reduce the use of rescue analgesia.

DESIGN

Randomized prospective double-blind study.

SETTING

Academic university hospital.

SUBJECTS

Sixty patients aged between 18 and 65 years designated as American Society of Anesthesiologists (ASA) class I or II who underwent unilateral arthroscopic shoulder surgery under general anesthesia were included in the study.

METHODS

Patients were equally divided into two groups-either the ESPB group (n=30) or the sham block group (n=30). ESPB was performed with 30 mL 0.25% bupivacaine at the T2 level in the ESPB group and sham block with 30 mL saline at the T2 level in the sham block group. Twenty minutes before the end of the operation, 100 mg tramadol was administered intravenously to the patients. Intravenous ibuprofen 400 mg 3 × 1 was ordered for the patients during the postoperative period. A patient control analgesia device including a dose of 10 µg/mL fentanyl was connected to the patients.

RESULTS

There were no statistical differences between groups in terms of demographical data. Postoperative fentanyl consumption was significantly lower in the ESPB group than in the sham block group (96.66 µg ±105.57 µg and 230 µg ±247.17 µg, respectively) (P=0.009). The need for rescue analgesia was significantly lower in the ESPB group than in the sham block group (26.66 mg ±35.43 mg and 48.5 mg ±35.45 mg, respectively) (P=0.020). Overall, the visual analog scale scores were significantly lower in the ESPB group than in the sham block group.

CONCLUSIONS

ESPB may provide effective analgesia treatment following arthroscopic shoulder surgery.

Ultrasound-guided erector spinae plane block for postoperative analgesia in patients undergoing open radical prostatectomy: A randomized, placebo-controlled trial

STUDY OBJECTIVE

The aim of this study was to evaluate the effect of ultrasound-guided erector spinae plane (ESP) block on postoperative pain in radical prostatectomy, which leads to both visceral and somatic pain.

DESIGN

Prospective, randomized, placebo controlled, double-blinded.

SETTING

University hospital.

PATIENTS

A total of ASA I-III, 50 patients aged 18-65 who were scheduled for elective open radical prostatectomy surgery.

INTERVENTIONS

Patients were randomly allocated to receive an ultrasound-guided ESP block, with either local anesthetic (10 mL of 1% lidocaine +10 mL of 0.5% bupivacaine) or placebo bilaterally.

MEASUREMENTS

The primary outcome was morphine consumption in the first 24 h after surgery. The secondary outcomes were NRS pain scores at rest and coughing, intraoperative remifentanil consumption and need for rescue analgesic during the first 24 h after surgery.

MAIN RESULTS

Both NRS scores for post-anesthesia care unit and NRS_rest scores for 1st hours were lower in Group ESPB (p < 0.001 and p = 0.033, respectively). Cumulative morphine consumption at 24 h post-surgery was similar between the groups (p = 0.447). Rescue analgesic requirement was higher in the placebo injection group than in the ESPB group at the 1st postoperative hour (p = 0.002).

CONCLUSIONS

In open radical prostatectomies, except for the first hour, ESP block is ineffective for pain scores and on morphine consumption compared to the placebo injection group in the postoperative period.

Blunt Chest Trauma and Regional Anesthesia for Analgesia of Multitrauma Patients in French Intensive Care Units: A National Survey

BACKGROUND

Chest injuries are associated with mortality among patients admitted to the intensive care unit (ICU) and require multimodal pain management strategies, including regional anesthesia (RA). We conducted a survey to determine the current practices of physicians working in ICUs regarding RA for the management of chest trauma in patients with multiple traumas.

METHODS

An online questionnaire was sent to medical doctors (n = 1230) working in French ICUs, using the Société Française d'Anesthésie Réanimation (SFAR) mailing list of its members. The questionnaire addressed 3 categories: general characteristics, practical aspects of RA, and indications and contraindications.

RESULTS

Among the 333 respondents (response rate = 27%), 78% and 40% of 156 respondents declared that they would consider using thoracic epidural analgesia (TEA) and thoracic paravertebral blockade (TPB), respectively. The main benefits declared for performing RA were the ability to have effective analgesia, a more effective cough, and early rehabilitation. For 70% of the respondents, trauma patients with a theoretical indication of RA did not receive TEA or TPB for the following reasons: the ICU had no experience of RA (62%), no anesthesiologist-intensivist working in the ICU (46%), contraindications (27%), ignorance of the SFAR guidelines (19%), and no RA protocol available (13%). In this survey, 95% of the respondents thought the prognosis of trauma patients could be influenced by the use of RA.

CONCLUSIONS

While TEA and TPB are underused because of several limitations related to the patterns of injuries in multitrauma patients, lack of both experience and confidence in combination with the absence of available protocols appear to be the major restraining factors, even if physicians are aware that patients' outcomes could be improved by RA. These results suggest the need to strengthen initial training and provide continuing education about RA in the ICU.

Ultrasound-guided erector spinae plane block in horses: a cadaver study

OBJECTIVES

To describe dye distribution and spinal nerve involvement after a simulated erector spinae plane (ESP) block performed on fresh equine cadavers.

STUDY DESIGN

Experimental cadaver study.

ANIMALS

A group of 11 adult equine cadavers.

METHODS

The spinal region surrounding the sixteenth thoracic vertebra (Th16) of one cadaver was removed and underwent magnetic resonance imaging. In 10 adult equine cadavers [body weight, 549 ± 58 kg (mean ± standard deviation)], 0.2 mL kg^-1 of a 50:1 2% lidocaine/dye solution was injected bilaterally (n = 20 injections) into the fascial plane between the transverse process of Th16 and the erector spinae muscles. An in-plane ultrasound-guided technique with a convex transducer was used to guide injection. Dissection was performed immediately following injection. The craniocaudal and lateral extent of dye distribution was measured (cm) and the number of vertebral bodies involved were counted (n = 20). Abdominal and thoracic cavities as well as the epidural space were also examined for presence of dye (yes/no) (n = 20). Further dissection was performed to evaluate if staining of the dorsal and ventral rami of the spinal nerves and sympathetic chain occurred (n = 14).

RESULTS

The thoracolumbar fascia was stained in 17/20 (85%) injections and three injections terminated intramuscularly. Multisegmental staining of the dorsal rami was observed in the 14 injections in which staining was evaluated. Ventral rami staining was observed in 3/14 injections where staining was evaluated. Epidural migration was observed in 4/20 (20%) injections. No evidence of dye was found in the thoracic and abdominal cavities or on the sympathetic chain.

CONCLUSIONS AND CLINICAL RELEVANCE

The ESP block may prove beneficial to desensitize structures innervated by the dorsal rami of the thoracic spinal nerves. Further investigation is necessary to evaluate complications caused by epidural contamination.

Transversus abdominis plane block in cat cadavers: anatomical description and comparison of injectate spread using two- and three-point approaches

OBJECTIVE

To describe the sonoanatomy of the abdominal wall in live cats and to compare the distribution pattern of two versus three ultrasound-guided transversus abdominis plane (TAP) injections using clinically applicable volumes of lidocaine-dye solution in cat cadavers.

STUDY DESIGN

Prospective anatomical study.

ANIMALS

A total of eight client-owned healthy cats and eight cat cadavers.

METHODS

Ultrasound anatomy of the abdominal wall, landmarks and sites for needle access were determined in live cats. Ultrasound-guided TAP injections were performed in eight thawed cat cadavers. Volumes of 0.25 or 0.16 mL kg^-1 per point of a lidocaine-dye solution were injected using either two [subcostal and preiliac (SP)] or three [subcostal, retrocostal and preiliac (SRP)] injection points, respectively. Each cadaver was then dissected to determine the injectate distribution and the number of thoracolumbar nerves stained with each approach. The target nerves were defined as the ventromedial branches of the thoracic nerves 10 (T10), T11, T12, T13 and lumbar nerves 1 (L1) and L2.

RESULTS

Sonoanatomy was consistent with anatomy upon dissection and the TAP was identified in all cadavers. A total of 16 subcostal, 16 preiliac and nine retrocostal TAP injections were performed. The overall staining success rate of the target nerves was 66.7% and 92.6% for the SP and SPR approaches, respectively (p = 0.02). The ventromedial branches of T10, T11, T12, T13, L1 and L2 were stained in 57.1%, 100.0%, 85.7%, 28.6%, 42.9% and 85.7%, and in 66.7%, 100.0%, 100.0%, 100.0%, 88.9% and 100.0% of the cases with the SP and SRP approaches, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

The SRP approach allowed a broader distribution around the target nerves, whereas a staining gap was observed at T13 and L1 with the SP approach. Further studies are necessary to investigate the analgesic effect of these approaches in a clinical setting.

Distribution of the T12 erector spinal muscle plane block in the dorsal region guided by ultrasound

Background

This study aimed to explore the distribution of the erector spinal muscle plane block of the thoracic 12 vertebral body (T12) in the dorsal region guided by ultrasound.

Methods

A total of 28 patients, who underwent elective lumbar surgery, were enrolled in the present study. These patients were aged between 18 and 65 years, and the American Society of Anesthesiologists (ASA) grade was 1 or 2. The block of the T12 transverse process erector spinal muscle was performed under the guidance of ultrasound, and each side was injected with 25 ml of 0.4% ropivacaine hydrochloride + 2 mg of dexamethasone. The back areas were measured using the cold-warm method (the back area was divided into 11 areas [T7–S1] with the body surface marker). At 10, 20, 30, 40, 50, and 60 min after the drug injection, the effectiveness of the regional block was recorded. The presence of puncture hematoma, local anesthesia drug poisoning, nausea, vomiting, headache, and dizziness after the block was recorded.

Results

The range of the T12 transverse process block was basically fixed at 30 min after the single injection. No pneumothorax, hematoma, or local anesthetic poisoning occurred in any of the patients.

Conclusion

The effective longitudinal plane of the T12 transverse process erector spinal muscle block was mainly distributed in the T9–L5 dorsal cutaneous branches, and the distribution of the block area was safe and stable.

The Role of Interfascial Plane Blocks in Paediatric Regional Anaesthesia: A Narrative Review of Current Perspectives and Updates

Regional anaesthesia has been increasingly used for analgesia in the perioperative period in paediatric anaesthesia for better pain control and improved patient outcomes. Interfascial plane blocks are considered as a subgroup of peripheral nerve blocks. The advent of ultrasound in modern regional anaesthesia practice has led to the evolution of various interfascial plane blocks. The ease of their performance and the low complication rates, compared with neuraxial anaesthesia, have led to their increased use in the perioperative period. Interfascial plane blocks are often incorporated in the multimodal analgesia regimen in the early recovery and ambulation after surgery protocols for various chest wall and abdominal surgeries. This achieves better pain control and decreases the requirements of opioids in the perioperative period, thereby facilitating early mobilization and discharge. This narrative review focuses on the relevant anatomic considerations, technique for the performance of each block along with its current applications and limitations, and includes a review of the current literature on various interfascial plane blocks in paediatric regional anaesthesia.

Anatomical basis of erector spinae plane block: a dissection and histotopographic pilot study

Purpose

Erector spinae plane (ESP) block is an interfascial blockade used in different clinical scenarios. This study investigated the ventral extent of dye diffusion in ESP block.

Methods

The ultrasound-guided ESP block was bilaterally performed with an injection at the T5 vertebral level (21-Gauge, 50 mm needle), using diluted black tissue marking dye (20 mL; 1:4 ratio with standard saline solution) instead of local anesthetic on two fresh-frozen corpses within the body donation program of the University of Padova. Subsequently, the gross anatomical dissection was performed by a combined posterior plus anterior approach, and the histotopographic examination completed.

Results

Macroscopically by gross anatomical dissection, the dye spreading ranged on the dorsal side of the chest from T2/3 to T10/11 with an extension up to 10 cm laterally, and on the ventral side of the chest from T2/3–T9/10. Microscopically by histotopographic examination, the dye diffused ventrally to the intercostal spaces (2–3 and 5–6 spaces on the right and left, respectively) by following the blood vessels coupled to the dorsal nerve passing through the costotransverse foramen.

Conclusions

The anterior pathway of dye diffusion from the site of injection within the erector spinae muscle group during an ESP block seems to follow the blood vessels and dorsal rami of spinal nerves, suggesting the passing through the costotransverse foramen to reach the anterior paravertebral space and the intercostal nerves. These findings display an anterior histotopographic diffusion of dye resembling a paravertebral block.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00540-020-02881-w.

Postoperative Thoracic Pain Treatment: Serratus Anterior or Erector Spinae Plane Block?

BACKGROUND

 Thoracic surgery is one of the most painful surgeries. Effective analgesia is important in postoperative pain management. In this study, we aimed to compare the two new fascial block techniques.

METHODS

 A total of 107 patients who underwent thoracic surgery between October 2018 and November 2019 were retrospectively evaluated. The study included 59 patients in the serratus anterior plane block (SAPB) group and 48 patients in the erector spinae plane block (ESPB) group. Both groups were administered 30 mL of 0.25% bupivacaine and their morphine consumption was evaluated by a patient-controlled analgesia (PCA) method during the 2nd, 6th, 12th, 24th, and 48th postoperative hours. Pain was measured with the visual analog scale (VAS). Intraoperative mean arterial pressure (MAP) and heart rate (HR) were recorded.

RESULTS

 During the first 24 hours, VAS values were significantly lower in the ESPB group (p < 0.05). Moreover, morphine consumption was significantly lower in the ESPB group in the 24th and 48th hours (p < 0.05). Intraoperative remifentanil consumption was also significantly lower in the ESPB group (p < 0.05). Intraoperative MAP in the ESPB group was found to be significantly lower after the 4th hour. HR was similar in both groups.

CONCLUSION

 ESPB was more effective compared with SAPB in postoperative thoracic pain management.

Bilateral ultrasound-guided erector spinae plane block in patients undergoing lumbar spinal fusion: A randomized controlled trial

STUDY OBJECTIVE

Spinal fusion surgery is associated with severe postoperative pain. We examined whether bilateral ultrasound-guided erector spinae plane block could alleviate postoperative pain in patients undergoing lumbar spinal fusion.

DESIGN

Blinded, randomized, controlled study.

SETTING

Tertiary university hospital, operating room, postoperative recovery room and ward.

PATIENTS

Sixty patients with American Society of Anesthesiologists grade I or II scheduled for lumbar spinal fusion surgery were randomized into the erector spinae plane block group (ESPB group) and the control group in a 1:1 ratio.

INTERVENTIONS

Pre-operative ultrasound-guided bilateral erector spinae plane block was performed in the ESPB group, while sham subcutaneous infiltration was performed in the control group.

MEASUREMENTS

The primary outcome was pain intensity at rest within 12 h postoperatively using the Numeric Rating Scale (NRS). Secondary outcomes included NRS pain scores at rest and on movement, postoperative opioid consumption and proportions of patients requiring opioid during the first 48 h after surgery.

MAIN RESULTS

The ESPB group (n = 30) showed significantly lower pain scores at rest at 4 h after surgery (estimated mean difference - 1.6, 95% confidence interval [CI] -2.4 to -0.8, p < 0.001), at 8 h (-1.3, 95% CI -1.9 to -0.6, p < 0.001), and at 12 h (-0.7, 95% CI -1.3 to -0.1, p = 0.023). The two groups showed similar pain scores at rest at 24 h after surgery (estimated mean difference - 0.2, 95% CI -0.8 to 0.5) and 48 h (-0.3, 95% CI -0.8 to 0.2). The ESPB group also showed significantly lower pain score on movement at 4 h after surgery (-1.5, 95% CI -2.5 to -0.6). The ESPB group showed a significantly smaller proportion of patients requiring sufentanil within 12 h after surgery (p = 0.020), and the group consumed significantly less sufentanil during that period (p = 0.042).

CONCLUSIONS

Bilateral ultrasound-guided erector spinae plane block improves postoperative analgesia in patients undergoing lumbar spinal fusion.

Erector Spinae Plane Block and Paravertebral Block for Breast Surgery: A Retrospective Propensity-Matched Noninferiority Trial

Purpose

Thoracic paravertebral block (TPVB) is an established analgesic technique for breast surgery although it is technically challenging. Erector spinae plane block (ESPB) requires less technical expertise and may be an alternative to TPVB. However, whether ESPB has similar analgesic effects to TPVB for breast surgery is still inconclusive. Moreover, information on sensory blockade of ESPB is scarce. Accordingly, we conducted this retrospective propensity-matched study to see if ESPB could provide comparable analgesic effects to TPVB in patients undergoing breast surgery. We also compared cutaneous sensory block levels after the two techniques.

Patients and Methods

In this retrospective cohort study, we analyzed data saved in our database and compared the two techniques using a propensity matching method. The data of patients who underwent unilateral breast surgery under general anesthesia with the addition of either TPVB or ESPB were identified. We considered that the analgesic efficacy of ESPB was noninferior to TPVB if both postoperative fentanyl consumption and area under the curve (AUC) for pain scores within 24 h were within 50 µg and 240 mm･h margins, respectively. Cutaneous sensory block levels, additional analgesic requirements, and complications were also compared between the two groups.

Results

Among 93 patients, 30 patients for each group were matched. Both postoperative fentanyl consumption and AUC for pain scores after ESPB were noninferior to those after TPVB. ESPB did not produce sensory blockade consistently, and the number of dermatomes was smaller after ESPB [1 (0–3)] [median (interquartile range)] than after TPVB [4 (2–5)] (P=0.002). No serious complications related to blocks were observed.

Conclusion

ESPB and TPVB provided comparable postoperative analgesia for 24 h in patients undergoing breast surgery. Dermatomal sensory blockade was, however, less apparent and narrower after ESPB than after TPVB.

Comparison between two approaches for the transversus abdominis plane block in canine cadavers

OBJECTIVE

To compare the dye distribution following either two lateral abdominal or one lateral abdominal and one subcostal ultrasound-guided transversus abdominis plane (TAP) injections of a clinically relevant volume of dye solution in dogs.

STUDY DESIGN

Randomized cadaveric study.

ANIMALS

A total of eight canine cadavers.

METHODS

On one side of each cadaver, two TAP injections were performed on the lateral aspect of the abdomen (approach LL), caudal to the last rib and cranial to the iliac crest. On the contralateral hemiabdomen, one subcostal (caudal to the costal arch) and one lateral abdominal injection (between last rib and iliac crest), were performed (approach SL). Side allocation was randomly determined. A spinal needle was introduced in-plane to the transducer for each injection of methylene blue (0.25 mL kg^-1). All cadavers were dissected to assess dye distribution and number of stained target nerves.

RESULTS

All injections were performed in the TAP. The proportion of target nerve staining was 53.5% versus 80.4% with approaches LL and SL, respectively (p = 0.005). Approach LL stained the first lumbar (L1) spinal nerve in 100% of injections and ninth thoracic (T9), T10, T11, T12, T13 and L2 were stained in 0%, 0%, 37.5%, 62.5%, 87.5% and 87.5% of injections, respectively. Approach SL stained T11, L1 and L2 in 100% of injections and T9, T10, T12 and T13 were stained in 37.5%, 87.5%, 75% and 62.5% of injections, respectively. Approach SL resulted in greater staining of nerves cranial to T12 compared with approach LL. The two approaches were equivalent in staining nerves caudal to T12.

CONCLUSIONS AND CLINICAL RELEVANCE

Approach SL provided a broader distribution of the injected solution than approach LL, which may result in a larger blocked area in live animals undergoing celiotomy.

A novel ultrasound-guided lateral quadratus lumborum block in dogs: a comparative cadaveric study of two approaches

OBJECTIVE

To describe an ultrasound-guided lateral quadratus lumborum (LQL) block technique and the spread characteristics of lidocaine-dye injected in the LQL plane using a transversal (LQL-T) or a longitudinal (LQL-L) approach.

STUDY DESIGN

Experimental anatomic study.

ANIMALS

A total of eight canine cadavers.

METHODS

Bilateral ultrasound-guided injections in the fascial plane lateral to the quadratus lumborum muscle and medial to the thoracolumbar fascia (LQL plane) with the needle directed at the first lumbar (L1) transverse process were performed using lidocaine-dye (0.3 mL kg^-1). Anatomical dissection determined the dye distribution, sympathetic trunk staining and number of spinal nerves stained circumferentially >1 cm.

RESULTS

The LQL fascial plane was ultrasonographically recognized in all cadavers and filled with lidocaine-dye in all eight cadavers with the LQL-T approach and in six with LQL-L. The injectate spread ventral to the lumbar transverse processes, around the quadratus lumborum muscle and dorsal to the transversalis fascia, affecting the ventral branches of the spinal nerves and the sympathetic trunk. A median (range) of 4 (3-5) and 3 (0-4) ventral branches of the thoracolumbar nerves were dyed with LQL-T and LQL-L approaches, respectively (p = 0.04). The most cranial nerve stained was the twelfth thoracic (T12) with the LQL-T approach and T13 with LQL-L, and the most caudal was L3 with both approaches. The incidence of sympathetic trunk staining was significantly higher using LQL-T (six injections) compared with LQL-L (one injection; p = 0.04). Dye was not observed in the lumbar plexus, epidural space or abdominal cavity.

CONCLUSIONS AND CLINICAL RELEVANCE

Ultrasound-guided LQL-T approach resulted in a more consistent spread toward the spinal nerves and sympathetic trunk compared with LQL-L approach. Further studies are necessary to assess the LQL block effectiveness and success rate in live dogs.

Development of a lateral ultrasound-guided approach for the proximal radial, ulnar, median and musculocutaneous (RUMM) nerve block in cats

OBJECTIVE

To describe a lateral ultrasound (US)-guided approach to the radial, ulnar, median and musculocutaneous (RUMM) nerves through a single proximal in-plane insertion in cats and to determine whether one or two injection points are required to successfully stain all the target nerves.

STUDY DESIGN

Prospective study.

ANIMALS

A total of eight client-owned healthy cats and 12 cat cadavers.

METHODS

In live cats, the US anatomy of the brachium, the landmarks and the site for needle accesses were determined. Then, 12 thawed feline cadavers were used to assess the spread of dye solution and nerve staining following the US-guided proximal-lateral-humeral RUMM injection using one and two injection points. Each cadaver was injected with 0.15 mL kg^-1 of a 0.25% new methylene blue solution in either a single injection aimed for the radial nerve of one limb (G1) or via two sites delivering 0.1 mL kg^-1 and 0.05 mL kg^-1 aimed for the radial and musculocutaneous nerves of the opposite limb, respectively (G2). Upon dissection, staining of the target nerves around their circumference for length of >1 cm was considered successful.

RESULTS

Sonoanatomy was consistent with anatomy upon dissection and target nerves were identified in all cadavers. Staining was 100% successful for the radial, median and ulnar nerves in both groups, and 41.7% and 100% for the musculocutaneous nerve in G1 and G2, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

This novel lateral US-guided approach for the proximal RUMM nerve block allowed a good identification of the nerves and related structures, and it provided a consistent muscular structure through which the needle could be easily guided. An injection performed in two aliquots (within the caudal and cranial compartments of the neurovascular sheath) appeared to be necessary to successfully stain all the target nerves.

The erector spinae plane block causes only cutaneous sensory loss on ipsilateral posterior thorax: a prospective observational volunteer study

BACKGROUND

Ultrasound-guided erector spine plane (ESP) block is widely used in perioperative analgesia for back, chest and abdominal surgery. The extent and distribution of this block remain controversial. This study was performed to assess the analgesia range of an ultrasound-guided ESP block.

METHODS

This prospective observational volunteer study consisted of 12 healthy volunteers. All volunteers received an erector spinae plane block at the left T5 transverse process using real-time ultrasound guidance. Measured the cutaneous sensory loss area (CSLA) and cutaneous sensory declination area (CSDA) using cold stimulation at different time points after blockade until its disappearance. The CSLA and CSDA were mapped and then calculated. The block range was described by spinous process level and lateral extension. The effective block duration for each volunteer was determined and recorded.

RESULTS

The cold sensory loss concentrates at T6-T9. The decline concentrates primarily at T4-T11. The lateral diffusion of block to the left side did not cross the posterior axillary line, and reached the posterior median line on the right. The area of cutaneous sensory loss was (172 ± 57) cm², and the area of cutaneous sensory decline was (414 ± 143) cm². The duration of cutaneous sensory decline was (586 ± 28) minutes.

CONCLUSION

Ultrasound-guided erector spine plane block with 20 mL of 0. 5% ropivacaine provided a widespread cutaneous sensory block in the posterior thorax, but did not reach the anterior chest, lateral chest, or abdominal walls. The range of the blockade suggested that the dorsal branch of spinal nerve was blocked.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, CHiCTR1800014438. Registered 13 January 2018.